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Industrial Air Controls
Industrial Air Controls
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Industrial Air Controls

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Basic training covering industrial pneumatics and pneumatic drawings

Basic training covering industrial pneumatics and pneumatic drawings

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  • Page Industrial Pneumatic Fundamentals Physical State Change – Elements (ex. O 2 , H 2 ) and Compounds (ex. H 2 O) undergo physical state change (gas, liquid, solid) by changing internal energy level (temperature). Characteristics of the element or compound stay the same Chemical State Change – Compound undergoes chemical state change by adding or subtracting another atom or compound. By adding O 2 atom to water [H 2 O], the compound becomes Hydrogen Peroxide [H 2 O 2 ]) Characteristics of the compound change.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals Assume free air is being compressed on a hot muggy day (95°F) muggy (95% humidity) day. 100 ft3 of air at 14.7-psia and 95°F will hold about 2-lbs. of water but if cooled to 70°F, will only hold about 1-lb. of water. So, if compressed air from this hot, muggy room flows into an air conditioned area, where it is cooled to 70°F, 1-1b. of water is going to condense out of the air, inside the air line.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals Standard Temperature Pressure (STP) – in pneumatics the term “normal air” is used. Normal air – air at STP (14.7-psia, 68°F, & 36% relative humidity). Free air – refers to atmospheric air at whatever temperature, pressure, and relative humidity conditions exist in the area. Standard Cubic Feet per Minute (SCFM) – term used with various air systems, blowers, fans, and compressors to indicate the volume of air (or gas) at STP that the equipment can move. Relative Humidity – the ratio of the amount of water vapor in air to the maximum amount of water vapor that could be present if the vapor were at its saturation conditions. Dew Point – the temperature to which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water.
  • Page Industrial Pneumatic Fundamentals Desiccant – a hygroscopic (taking up and retaining moisture) substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately well-sealed container. Commonly encountered pre-packaged desiccants are solids and work through absorption or adsorption of water, or a combination of the two. Normal air – air at STP (14.7-psia, 68°F, & 36% relative humidity). Adsorption – a process that occurs when a gas or liquid solute accumulates on the surface of a solid or, more rarely, a liquid (adsorbent), forming a molecular or atomic film (the adsorbate). It is different from absorption, in which a substance diffuses into a liquid or solid to form a solution. Absorption – a physical or chemical phenomenon or a process in which atoms, molecules, or ions enter some bulk phase – gas, liquid, or solid material. This is a different process from adsorption since the molecules are taken up by the volume, not by the surface. Relative Humidity – the ratio of the amount of water vapor in air to the maximum amount of water vapor that could be present if the vapor were at its saturation conditions.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Hydraulic fluid in a working system contains energy in two forms: Kinetic energy by virtue of the fluid’s weight and velocity Potential energy in the form of pressure. Daniel Bernoulli, a Swiss scientist, demonstrated that in a system with a constant flow rate, energy is transformed from one form to the other each time the pipe cross-section size changes. As shown in the illustration, when the cross-sectional area of a flow path increases, the velocity (kinetic energy) of the fluid decreases. Bernoulli’s principle says that if the flow rate is constant, the sums of the kinetic energy and the pressure energy at various points in a system must be constant. Therefore, if the kinetic energy decreases, it results in an increase in the pressure energy. This transformation of energy from one kind to the other keeps the sum of the two energies constant. Likewise, when the cross-sectional area of a flow path decreases, the increase of kinetic energy (velocity) produces a corresponding decrease in the pressure energy. The use of a venturi in an automobile engine carburetor is a familiar example of Bernoulli’s principle. Air flowing through the carburetor barrel is reduced in pressure as it passes through a reduced cross section of the throat. The decrease in pressure permits gasoline to flow, vaporize, and mix with the air stream. Bernoulli’s principle is an important factor in the design of spool-type hydraulic valves. In such valves, changes in fluid velocity are common. If the maximum flow rate of the valve is exceeded, the pressure changes as a result of Bernoulli’s principle can produce unbalanced axial forces within the valve. These forces may become great enough to overpower the valve’s actuator and cause the valve to malfunction.
  • In the 1700's a number of people investigated gas behavior in the laboratory. Robert Boyle investigated the relationship between the volume of a dry ideal gas and its pressure. Since there are four variables that can be altered in a gas sample, in order to investigate how one variable will affect another, all other variables must be held constant or fixed. Boyle fixed the amount of gas and its temperature during his investigation. He found that when he manipulated the pressure, the volume responded in the opposite direction. For example, when Boyle increased the pressure on a gas sample, the volume would decrease. Mathematically, PV = constant value if the gas is behaving as an Ideal Gas. Boyles’ Law, states: “if the temperature of a confined body of gas is maintained constant, the absolute pressure is inversely proportional to the volume.” This simply means that when the volume of a confined gas is reduced by some amount, its absolute pressure will increase by the same amount. (It is important to note that this law is in terms of absolute” pressure, not “gage pressure.” Absolute pressure is 14.7 psi more than the reading of a pressure gage. The reason for this is that a pressure gage shows zero pounds pressure when it is open to the atmosphere, although 14.7 pounds is actually being exerted upon it.) Boyles law means, as illustrated, P1 X V1 = P2 X V2 = P3 X V3 = constant where P = pressure and V= volume. A practical application illustrating Boyle’s Law would be the action of a syringe. When we draw fluids into a syringe, we increase the volume inside the syringe, this correspondingly decreases the pressure on the inside where the pressure on the outside of the syringe is greater and forces fluid into the syringe. If we reverse the action and push the plunger in on the syringe we are decreasing the volume on the inside which will increase the pressure inside making the pressure greater than on the outside and fluids are forced out.
  • Page Industrial Pneumatic Fundamentals Boyle’s law states: the product of absolute pressure and volume of a given mass of gas remains constant if the temperature of the gas remains constant. This process is called isothermal (constant temperature). It must be slow enough for heat to flow out of and into the air as it is compressed and expanded. The following slides illustrate this affect. Basically what is being shown here by way of example is that the Pressure times Volume on one side of the cylinder is the same as the pressure and volume on the other side of the cylinder. If the volume is less, then the pressure is increased and if the volume is greater the pressure is decreased.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Jacques Charles investigated the relationship between the volume of a gas and how it changes with temperature. He noted that the volume of a gas increased with the temperature. Charles' Law states that the volume of a given amount of dry ideal gas is directly proportional to the Kelvin Temperature provided the amount of gas and the pressure remain fixed. When we plot the volume of a gas against the Kelvin temperature, it forms a straight line. The mathematical statement is that the V / T = a constant. An example of Charles' Law would be what happens when a hot air balloon has air heated. The air expands and fills the balloon. Of course, other physical principles cause the balloon to rise against the gravitational force. As the air inside the balloon expands, the balloon gets bigger and displaces more air. The displaced air produces a buoyant force that counters the gravitational force and causes the balloon to rise.
  • Page Industrial Pneumatic Fundamentals Charles’ Law states: For a given mass of gas at constant pressure, the volume is proportional to the absolute temperature. Assuming no friction, a volume will change to maintain constant pressure. From an ambient of 20°C a change of 73.25°C will produce a 25% change of volume. 0° Celsius = 273°K The following slides illustrate this affect.
  • Page Industrial Pneumatic Fundamentals If the pressure is constant and the temperature increases on one side of the cylinder, then the volume will increase on the heated side of the cylinder.
  • Page Industrial Pneumatic Fundamentals If the pressure is constant and the temperature decreases on one side of the cylinder, then the volume will decrease on the cooled side of the cylinder.
  • Page Industrial Pneumatic Fundamentals If the temperature increases on both sides of the cylinder and the pressure is constant, then there is no change in volume.
  • Page Industrial Pneumatic Fundamentals With Boyle’s and Charles ’, there are only two variables that are allowed to change. The other two variables were held fixed or constant. This is rather unrealistic since, in most cases, a sample of gas will be under the influence of all three of the other variables changing. When this happens, we are dealing with the Combined Gas Law.
  • Page Industrial Pneumatic Fundamentals In English: The volume of a dry gas varies inversely with its pressure provided the temperature remains constant. Note: V= Volume, P = Pressure absolute, k=constant
  • Page Industrial Pneumatic Fundamentals In English: The volume of a dry gas varies directly with its temperature provided the pressure remains constant. Note: T = Temperature absolute (°K)
  • Page Industrial Pneumatic Fundamentals In English: The product of the initial pressure, initial volume, and new temperature (°K) of an enclosed gas is equal to the product of the new pressure, new volume, and initial temperature. Note: T = Temperature absolute (°K)
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals Pressure in pneumatic systems is measured in one of three scales: absolute (psia) gauge (psig) vacuum ("Hg). On the Gauge pressure scale, “zero psig” occurs at current atmospheric pressure (a flat tire is at 0-psig). On the Vacuum pressure scale, “zero "Hg” occurs at sea level and a perfect vacuum is at 29.92 "Hg (many gauges read 0 to 30 "Hg, but 30" of vacuum can never actually be reached. On the Absolute pressure scale, “zero psia” occurs in a perfect vacuum (outer space), and sea level pressure is 14.7-psia.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals PSI (pounds per square inch) of pressure. PSIG = pounds per square inch gauge PSIA = pounds per square inch atmospheric
  • Page Industrial Pneumatic Fundamentals Either of two pressure scales are used to measure pressure in a fluid power system — an absolute scale or a gage scale.
  • The gage pressure scale measures pressure relative to the ambient atmosphere and thus begins at the point of atmospheric pressure. The unit of measure used for pneumatic fluid power is psi (bar). An ordinary pressure gage used in a fluid power system operates on this scale. The gage scale indicates fluid pressure exerted by the gas in the system. To measure the total pressure of the gas in the system including atmospheric pressure, the absolute pressure scale is used. A pressure gage is a device which measures the intensity of a force applied to a fluid. Two types of pressure gages are most commonly used in a pneumatic system — the bourdon tube gage and the plunger gage.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals A plunger pressure gage consists of a plunger connected to system pressure, a bias spring, pointer, and a scale calibrated in pressure units of psi (bar). An example would be auto tire gages. How a plunger gage works A plunger gauge works much like a single direction cylinder. As pressure in a system rises, the plunger is moved by the pressure acting against the force of the bias spring. This movement causes the pointer attached to the plunger to indicate the appropriate pressure on the scale. Plunger gages are commonly found in hydraulic fluid power systems.
  • Page Industrial Pneumatic Fundamentals A bourdon tube gage basically consists of a dial face calibrated in the desired pressure units and a needle pointer attached through a linkage to flexible metal curved tube, called a bourdon tube. The bourdon tube is connected to system pressure. As pressure in a system rises, the bourdon tube tends to straighten out. This action causes the pointer to move and indicate the appropriate pressure on the dial face. Bourdon tube gages are relatively precise instruments. They are frequently used for laboratory purposes and on systems where pressure determination is relatively important. Their accuracies range from ±3% to ±.1% of full scale reading, depending on the accuracy level of the gage. Pressure gages usually measure system pressure which is above atmospheric. The units are in psi (bar) and the scale is gage pressure or PSIG. To determine an absolute pressure from a gage reading, add the atmospheric pressure to the gage reading. For example, if a machine were operating under normal conditions at sea level and system pressure were 122 PSIG, the absolute pressure would be 136.7 PSIA (122 PSIG + 14.7 psi (9.4 bar).
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals A vacuum gage is a bourdon tube gage which measures pressures below atmospheric. A vacuum gage is generally calibrated from 0-30. Each division typically represents the pressure exerted by one inch of mercury. At sea level, to determine an absolute pressure from a vacuum gage reading, subtract the vacuum in inches of mercury from 29.92. For example, a vacuum reading of 7 in. Hg. at sea level is actually an absolute pressure of 22.92 in. Hg. or approximately 23 in. Hg.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals When force or pressure is applied to a solid, the force is in the direction of the force.
  • Page Industrial Pneumatic Fundamentals When force or pressure is applied to a liquid, the force is in all directions. Note: Liquid is not compressible. Hydraulic systems use a incompressible fluid such as oil or water, to transmit forces from one location to another within the fluid. Most aircraft use hydraulics in the braking systems and landing gear.
  • Page Industrial Pneumatic Fundamentals When force or pressure is applied to a gas, the force is in all directions. Note: Gas is compressible. Pneumatic systems use compressible fluid such as air, in their operation. Some aircraft utilize pneumatic systems for their brakes, landing gear, and movement of flaps.
  • A physical law that applies to fluid flow is known as Pascal’s Law. Pascal’s Law simply stated says: “Pressure applied on a confined fluid is transmitted undiminished in all directions, and acts with equal force on equal areas, and at right angles to the surface.” For example, a pressurized fluid confined in a pipe, as shown in the illustration, will act equally in all directions and at right angles to the inside surface of the pipe.
  • Page Industrial Pneumatic Fundamentals Force transmission is also called Pascal's Principle Pascal's law. It was developed by French mathematician Blaise Pascal who stated that when there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container. The fluid pressure at all points in a connected body of an incompressible fluid (liquid) at rest, which are at the same absolute height, are the same, even if additional pressure is applied on the fluid at some place. Can be interpreted as saying that any change in pressure applied at any given point of the fluid (liquid or gas) is transmitted undiminished throughout the fluid. A device is needed (an air compressor) to supply compressed air at a desired pressure.
  • Page Industrial Pneumatic Fundamentals This basic representation of Pascal’s law illustrates the basic principle of how cylinders work.
  • Using the information from the previous slide, calculate the pressure if the Force equals 1000 pounds and the area is a 100 square inches. The answer is 100 psi. The force triangle is a simplified method of quickly converting the formula F= P x A
  • Page Industrial Pneumatic Fundamentals Primary air treatment – conditioning of air before, during, and after compression; but before distribution. Secondary air treatment – conditioning of air at or near the point of usage. Conditioning equipment: Intake air filters Intercoolers After coolers Separators Refrigerators Oil scrubbers Absorption or Deliquescent Units
  • A compressed air system in normally comprised of a primary mover, compressor, a tank or receiver. Depending on the operational requirements, compressors are driven either by a primary mover such as an electric motor or by an internal combustion engine In factories, compressors are usually driven by electric motors.
  • The purpose of a regulator is to keep the operating pressure (secondary pressure) constant regardless of fluctuations in either the line pressure (primary pressure) or air consumption. The inlet pressure must always be higher than the outlet pressure. The pressure is regulated by a diaphragm. The outlet pressure acts on one side of the diaphragm, and a spring acts on the other side. The spring force can be adjusted by means of an adjusting screw. When the outlet pressure increases, the diaphragm moves against the spring force causing the valve seat to be partially or fully closed. Thus, the pressure is regulated by the flow volume. When air is used, the operating pressure drops and the spring opens the valve. Regulation of the preset outlet pressure is by a continual opening and closing of the valve. To prevent flutter, spring damping is used above the valve disc The operating pressure is shown on a gauge. If the pressure on the outlet increases beyond the preset pressure, the diaphragm is pressed against the spring. The centerpiece of the diaphragm then opens and compressed air can flow to the atmosphere through the vent holes in the housing.
  • Most point-of-use filters claim to remove condensed water, typically via a form of cyclone separator at their inlet end. These filters must be matched to the intended airflow, rather than acceptable pressure drop. If the filter is intended to remove moisture, an integral automatic float-type drain should be provided to periodically remove accumulated liquids from the filter bowl. Basic Operation: The compressed air filter removes contaminants, as well as water which has already condensed, from the compressed air flowing through it. As the compressed air enters the filter bowl, it must flow through guide slots in the baffle plate. This causes the compressed air to rotate. Liquid particles and large particles of dirt are centrifuged out of the air and collect in the lower part of the filter bowl. The filter with an average mesh width of 40 microns removes additional dirt particles. The filter should be cleaned or replaced periodically. Clean compressed air flows via the pressure regulator to the oil, and from there to the connected equipment. The condensate which has collected in the lower part of the filter bowl must be drained via drain when the maximum condensate level is reached. The filter unit could be fitted with an automatic water separator if greater amounts of condensate are generated.
  • The purpose of a compressed air lubricator is to provide the components with sufficient lubricant. Lubricants are used to reduce the wear of the moving parts, keep friction low, and protect the equipment from corrosion. The compressed air flows through the lubricator from inlet to outlet. The size contraction at the valve generates a pressure gradient. A vacuum is created in the duct and drip chamber as a result of suction. This vacuum causes drops of oil to be drawn in through the duct and oil passage. These oil drops flow through the drip chamber and the drip duct and are atomized by the air. The lubricated air exits the lubricator through the outlet. The flow cross section changes according to the amount of air flow, thus changing the pressure gradient. The rate of oil flow is also changed. This flow rate can be subsequently adjusted at an adjustment screw located at the upper end of the oil passage.
  • The Venturi Principle or Effect is actually an example of Bernoulli's Principle. The air flow through the restriction causes decrease in pressure, is called differential pressure. This simply means that the pressure at one point is different from the pressure at another point. For this reason, the principle is sometimes called Bernoulli's Law of Pressure Differential. When the air passing through the tube reaches the restriction, it speeds up. According to Bernoulli's Principle, it then should exert less pressure. This actually causes a vacuum like affect. This same principle is used to generate vacuum in air vacuum cups and valves.
  • FRL stands for filter-regulator-lubricator. An FRL unit combines the three components into a pre-piped package for easy installation. Branches of a pneumatic system are generally equipped with FRL’s so that individual actuators and work stations receive filtered, regulated, and lubricated air meeting their specific requirements. FRL design considerations: The following is a set of definite rules that should be followed when designing systems protected with FRLs. Make sure they are sized for the maximum flow rate in the portion of the circuit they service. Placement of these devices should be as close as practical to the component being serviced. Their placement should also be in an area of easy accessibility. This is especially true for units requiring regular maintenance, such as filling, adjusting or cleaning. Install a shut off valve (possibly a lockout type, shutoff exhaust) ahead of the unit to
  • The type of compressor used depends on the operational demands, working pressure, and delivery volume. There are two basic types of compressors The first group operates on the displacement principle. Air is compressed by containing ft in a chamber and then reducing the volume of this chamber. This type is called a piston compressor. The second group operates on the air-flow principle. They draw air in on one side and compress it by mass acceleration.
  • The reciprocating piston compressor is the most widely used compressor. It can be used not only for compressing to low and medium pressures, but also for compressing to high pressure. The pressure range extends from atmospheric (15 psi / 1 bar) to several thousand times that. Multistage compressors are required for compressing from lower to higher pressure. The drawn-in air is compressed by the first stage, cooled, and then further compressed by the next stage. The volume of the second stage is smaller than the first. Heat arises during compression and must be removed by a cooling system. Reciprocating piston compressors are made as air-cooled designs and also as water- cooled designs.
  • This type of compressor belongs to the piston compressor group. The piston is separated from the suction chamber by a diaphragm so the air does not come in contact with the reciprocating parts. Thus, the air is kept free of oil. For this reason, it is preferred in the food preparation, pharmaceutical and chemical industries.
  • An eccentrically-mounted rotor rotates in a cylindrical housing having an inlet and outlet. The advantages of this compressor are its compact dimensions, quiet running, and smooth, steady air delivery. Sliding vanes are contained in slots in the rotor and form chambers with the housing wall. When rotating, the centrifugal energy forces the vanes against the wall and because of the shape of the housing, the chambers are increased or reduced in size.
  • This type of compressor has two intermeshing rotors; one having a convex profile and the other a concave profile. The air enters at one end of the rotor and is displaced along the axis of the rotors.
  • In these compressors, the air is conveyed from one side to the other without any change in volume. The piston edges seal on the pressure side.
  • These work on the air-flow principle and are especially suitable for large delivery volumes. Flow compressors are made as axial, as shown above, and radial types. The air-flow is converted by one or more turbine wheels to flow velocity. This kinetic energy is converted to pressure energy.
  • A radial flow compressor may also be termed a Centrifugal compressor. Air is accelerated radially and outward from chamber to chamber. At the most outward position, it reverses its flow and returns to the inside (shaft) area. From there, it accelerates outward again, progressing from chamber to chamber until it reaches maximum pressure at the compressed air outlet.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals
  • An operator is the mechanism that causes a valve to change state They are classified as manual, mechanical and electrical
  • Page Industrial Pneumatic Fundamentals 27
  • Page Industrial Pneumatic Fundamentals 27
  • Page Industrial Pneumatic Fundamentals 27
  • Page Industrial Pneumatic Fundamentals The first figure is the number of main ports. Inlets, outlets, and exhausts excluding signal and external pilot supplies The second figure is the number of states the valve has. A 3/2 valve has 3 ports, and 2 states, normal and operated. The symbols illustrate these functions: can you identify the symbols based on function
  • This slide and the following one illustrates the operation of a 5 ported, 2 position valve. This valve’s position is changed by compressed air from alternate sides and maintains its momentary position until it receives a counter-impulse. When compressed air is applied, the pilot spool is shifted. A disc with a sealing ring in the center of the pilot spool connects or disconnects the working lines ‘A’ (2) or ‘B’ (4) with the supply connection ‘P’ (1). Exhaust air flows through ‘R’ (3) or ‘S’ (5). Input air is applied through ‘Y’ (12) or ‘Z’ (14).
  • Page Industrial Pneumatic Fundamentals For similarly designed valves the amount of air flow through the valve usually increases with the port size. Port size alone however cannot be relied upon to give a standard value of flow as this is dependent on the design of the valve internals.
  • Page Industrial Pneumatic Fundamentals
  • Shut off valves are used to shutoff air flow, much like a water faucet in principle.
  • Page Industrial Pneumatic Fundamentals Provide valve operation from a low operating force In the normal position the lever arm is holding the bleed orifice closed The differential piston has supply pressure acting on the small end, also the large end through a restrictor in the piston A light operating force will lift the bleed seal allowing air to escape Flow through the piston is slower than the bleed orifice so the pressure is lost and the piston changes state Releasing the lever causes the piston to reset
  • Page Industrial Pneumatic Fundamentals Selector switch valves allow manual control of air supply In the left position in the above example pressure supplied at port 1 is supplied to outlet port 2 and exhaust at port 3 is connected to port 4. In the right position in the above example pressure supplied at port 1 is supplied to outlet port 4 and exhaust at port 3 is connected to port 2. A spring operator indicates that the switch is momentary and a detented operator indicates a maintained switch.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals Main pressure applied at the input port 1 which acts to hold the spool to the left. A weak or slowly rising pressure of a input signal that is applied to port 12 needs only to reach about 50% of the pressure at port 1 to operate the valve Port 1 is then connected to port 2 Removing the signal from port 12 allows the differential force to reset the valve.
  • Page Industrial Pneumatic Fundamentals
  • Page Industrial Pneumatic Fundamentals Uni-directional, line mounted adjustable flow regulator. Free flow in one direction, adjustable restricted flow in the other direction. This is accomplish by incorporating a check valve into the flow regulator. In one direction the check valve opens bypassing the flow regulator and in the other direction it closes allowing the regulator to function. The following slide illustrates the basic application of flow regulators to a cylinder.
  • Page Industrial Pneumatic Fundamentals By the use of flow regulators the outstroke speed and in stroke speed of a piston rod can be independently adjusted. Speed is regulated by controlling the flow of air to the exhaust of the cylinder. A secondary purpose of using the exhaust to control the speed is also to allow the exhaust air to act as a simple shock absorber to the cylinder. The front port regulator controls the outstroke speed and the rear port regulator controls the in stroke speed. The basic reason or application of this is to prevent the cylinder operation from mechanically slamming the equipment it is attached to against mechanical stops thereby decreasing wear and tear to the equipment.
  • Page Industrial Pneumatic Fundamentals In some applications cylinder speed can be increased by 50% when using a quick exhaust valve When operated, air from the front of the cylinder exhausts directly through the quick exhaust valve The faster exhaust gives a lower back pressure in the cylinder therefore a higher pressure differential to drive out the piston rod Port 2 is connected directly to the end cover of a cylinder Port 1 receives air from the control valve Air flows past the lips of the seal to drive the cylinder When the control valve is exhausted, the seal flips to the right opening the large direct flow path Air is exhausted very rapidly from the cylinder for increased speed
  • In the age of microchips and programmable controllers, air logic can still provide an effective, efficient, and inexpensive means of control for certain pneumatic machines. Electrical and electronic devices control most fluid power circuits. Relay logic circuits, programmable controllers, or computers are common control methods. But another way to control pneumatic systems is with air logic. Air logic controls can perform any function normally handled by relays, pressure or vacuum switches, time delays, limit switches, and counters. The circuitry is similar, but compressed air is the control medium instead of electrical current. Environments with high levels of moisture or dust are excellent places for air logic controls. No danger from explosion or electrical shock is presented by the air-logic system. Water can splash on the controls without affecting their operation. If there is an external explosion, the control media - clean compressed air - cannot ignite. Two basic roadblocks to using air-logic control are a lack of understanding of how the components work and an inability to read the special schematic drawings. The components used for air logic controls are basically miniaturized 3- and 4-way air valves. The actions of these valves turn functions on or off, just as relays or switches do, then exhaust the spent signal. The symbols that were developed for air logic are similar to electronic symbols. In fact, some manufacturers use modified electrical symbols and ladder diagrams to show circuitry. The following slides illustrate a few of these logic elements.
  • Page Industrial Pneumatic Fundamentals The OR valve has two inlets and one outlet. If compressed air is applied to an inlet a ball will seal off the opposite inlet and air flows from that inlet to the outlet. When air flow is reversed (if a cylinder or valve is exhausted) back to the outlet, the ball remains in its previously assumed position because of the exhaust pressure.
  • Page Industrial Pneumatic Fundamentals The AND valve has two inlets and one outlet. Compressed air flows from the outlet only if air is applied to both inlets. Only one input to an inlet blocks the flow because of the force differential across the spool. The output signal “3” is present only when signals “1” AND “2” are present simultaneously.
  • An anti-tie down logic element requires both inputs to be present almost simultaneously to allow and output. The main use is for air circuits that requires an operator to press switches with both hands to allow the output to function. If either input or hand is dropped than the circuit drops.
  • Positive Timer: A positive timer is sometimes referred to as normally closed or on-delay. Logically it can be looked at as a normally closed relay contact (for air) that is timed to open. When the input is applied the output will be turned on after the adjusted time period. Internally a small air reservoir will fill until the switching point is reached. The adjustment to the timer is a flow control that adjusts how fast the reservoir. The input must be removed to allow the reservoir to exhaust at which time the delay cycle can be repeated. Negative Timer: Sometimes referred to as normally open or off delay. Logically it can be looked at as a normally open relay contact (for air) that is timed to close. When the input is applied the output will be turned off after the adjusted time period. Internally a small air reservoir will fill until the switching point is reached. The adjustment is a flow control that adjusts how fast the reservoir fills. The input must be removed to allow the reservoir to exhaust at which time the delay cycle can be repeated. Note: the symbol is the same as the positive symbol with the addition of a circle (sometimes referred to as the not circle).
  • A one shot is sometimes called an impulse time. A one shot timer takes a signal and passes it on to the circuit. At the same time the input signal is going through an orifice to an accumulator chamber. The setting of the orifice and size of the accumulator gives a certain time delay before the normally open 3-way valve closes. After a ONE SHOT times out and closes, it remains closed as long as it has an input signal. The input will need to be cycled off then on again in order to repeat the pulse.
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  • The typical cylinder consists of a barrel, base cap, bearing cap, piston with seal, piston rod, bushing, wiper; in addition, there are the connecting parts and seals. The cylinder barrel is usually made of seamless drawn tube. To increase the life of the sealing components, the bore of the cylinder barrel is precision-machined (honed). For special applications, the cylinder barrel is made of aluminum, brass, or steel tube with a hard-chrome bearing surface. These special designs are used where operation is infrequent, or where there are corrosive influences. The base cap and the bearing cap are usually made of cast metal. The two caps can be fastened to the cylinder barrel by tie rods, threads, or flanges. The piston rod is usually made from heat treated steel. A certain percentage of chrome in the steel protects against rusting. Frequently, the threads are rolled to reduce the possibility of fracture due to stress cracks. The rod may be hardened and the surface is usually polished. For hydraulic applications, a hard-chromed or hardened piston rod must be used. A packing ring is fitted into the bearing cap to seal the piston rod. The bushing guides the piston rod, and may be made of sintered bronze or plastic-coated metal. The wiper prevents dust and dirt particles from entering the cylinder space. The seal provides a dynamic seal between the piston and barrel. Various materials are used; selection depends on the operating temperature range expected.
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  • Cylinder force is dependant upon the air pressure applied to the cylinder piston and frictional resistance of the sealing components. Piston force is force is calculated by the useful piston area times the operational pressure. In the case of the rod end of a cylinder the area of the piston rod must be subtracted from the area of the piston when the force exerted is on the rod end of the cylinder. In the formula Force = Area X Pressure Force is in pounds (lbs) Area is in square inches (in²) Pressure is in pounds per square inch (psi).
  • Area = 113 sq in. Area of rod end = 7 sq in. If a chain pull has been determined to be 2225 pounds what should the air pressure be? Because the pressure must push against the pull force then the area of the rod must subtracted from the area of the piston. Therefore the air pressure to pull 2225 pounds will equal 21 pounds per square inch. Pressure = 2225 / (113 – 7) = 21 psi.
  • Cylinder speed is difficult to predict due to the compressibility of air. Speed depends also on the supply pressure and the load on the cylinder. If, for example if we put a large hole in the side of an air tank the air will flow out quickly whereas if the hole is very small it will flow out slowly. This principle is used by flow control valves to control the speed of cylinders. If we put a large weight or load on a cylinder the cylinder will also move or extend much slower because the resistance of the load will cause the air to compress. The flow rate into a cylinder is based on the amount of air needed to move the piston load at a specified speed. First volume of the cylinder must be determined using the formula V=A x S where A is area of the piston and S is the cylinder stroke. For U.S. units use inches. Second the compression ratio must be calculated. This is the absolute pressure entering the cylinder divided by the atmospheric pressure. Finally the flow rate needed for the pneumatic system, which is measured in CFM or cubic feet per minute, will need to be calculated. For example calculate the CFM of a 4 inch bore cylinder with a 42 inch stroke that extends in 2 seconds. Find the flow rate if the load is 628 pounds. Using the force calculation we find pressure (P=F/A) which when calculated is 50 psi. Then we calculate cylinder volume (V= A x S) which equals 528 cubic inches. Then the compression ratio (50+14.7 divided by 14.7) which equals 4.4 Finally, now that we know the volume, compression ratio and time we can calculate the CFM needed by the system which when calculated equals 40.3.
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  • In single-acting cylinders compressed air is applied to only one side. These cylinders can produce work in only one direction. The return movement of the piston is effected by a built-in spring or by an external force. Air is used for only one direction of movement. In single-acting cylinders with built-in spring, the stroke is limited by the length of the spring. Most single-acting cylinders are built with stroke lengths of up to approx. 4 in. / 100 mm. Application: These working elements are used mainly for operations that involve clamping, ejecting, pressing in, lifting, or feeding.
  • In a double-acting cylinder, the force exerted by the compressed air moves the piston in two directions. The pneumatic force is applied on both advance and return movements. Double-acting cylinders are used when the piston is required to perform a work function on both the advance and return movements. In principle, the stroke length of the cylinder is unlimited, although buckling and bending of the extended piston rod must be considered. Here, too, the type of seal is a double cup packing.
  • This cylinder has a piston rod protruding from both ends. The piston rod passes right through the cylinder. Guidance of the piston rod is better because there are two bearing positions. With this design small lateral loads can also be applied. Applications: A signal sending unit can be attached to the free side of the piston rod. The force is the same in both directions of motion because the piston area is the same.
  • Trouble-free use of fluid power cylinders and their ability to serve and remain leak-free depends, in large part, on properly mounting the component for the particular application. The designer must determine the loading the cylinder will experience and mount it accordingly. The National Fluid Power Association, NFPA, has standardized on a number of dimensions for square-headed tie rod cylinders to promote cylinder interchangeability between manufacturers. Part of this standardization program includes cylinder mounting styles, which generally provide: Straight-line force transfer with fixed mounts that absorb force on the centerline of the cylinder. Straight-line force transfer with fixed mounts that do not absorb force on the centerline of the cylinder. Pivot force transfer with pivot mounts which absorb force on the centerline of the cylinder and allow the cylinder to change alignment in one plane.
  • Air motors are used to produce continuous rotary power from a compressed air system. They boast a number of advantages over electric motors: Because they do not require electrical power, air motors can be used in volatile atmospheres. They generally have a higher power density, so a smaller air motor can deliver the same power as its electric counterpart. Unlike electric motors, many air motors can operate without the need for auxiliary speed reducers. Overloads that exceed stall torque generally cause no harm to air motors. With electric motors, overloads can trip circuit breakers, so an operator must reset them before restarting equipment. Air motor speed can be regulated through simple flow-control valves instead of expensive and complicated electronic speed controls. Air motor torque can be varied simply by regulating pressure. Air motors do not need magnetic starters, overload protection, or the host of other support components required by electric motors, and Air motors generate far less heat than electric motors.
  • As one would expect, electric motors do possess some advantages over air motors: If no convenient source of compressed air exists for an application, the cost of an air motor and its associated support equipment (motor-driven compressor, controls, filters, valves, etc.) will exceed that of an electric motor and its support equipment. Air motors consume relatively expensive compressed air, so the cost of operating them will probably be greater than that of operating electric motors. Even though electronic speed controls escalate the cost of electric motor drives, they control speed more accurately (within ±1% of desired speed) than air motor controls do. Air motors operated directly from a plant air system are susceptible to speed and torque variations if system flow and pressure fluctuate.
  • Piston air motors are used in applications requiring high power, high starting torque, and accurate speed control at low speeds. They have either two, three, four, five, or six cylinders arranged either axially or radially within a housing. Output torque is developed by pressure acting on pistons that reciprocate within the cylinders. Motors with four or more cylinders provide relatively smooth torque at a given operating speed because power pulses overlap: two or more pistons undergo a power stroke at any time within a revolution. Motors designed with overlapping power strokes and accurate balancing are vibration-free at all speeds. Power developed by a piston motor depends on the inlet pressure, the number of pistons, and piston area, stroke, and speed. At any given inlet pressure, more power can be obtained from a motor that runs at a higher speed, has a larger piston diameter, more pistons, or longer stroke. Speed-limiting factors are the inertia of the moving parts (which has a greater effect in radial- than in axial-piston motors) and the design of the valve that controls inlet and exhaust to the pistons.
  • Because of their simple construction and low weight, pneumatic motors are usually built as sliding vane rotary motors. The principle of operation is the opposite of the sliding-vane compressor. An eccentric rotor is contained in a cylindrical chamber. Slots are arranged in the rotor. Vanes are guided by the slots of the rotor and are forced outward against the inner wall of the cylinder by centrifugal force. This ensures that the individual chambers are sealed. Small amounts of compressed air in the bottom of the slots cause the vanes to partially press against the inner wall of the cylinder even before the motor starts to move. In other designs, the vanes are forced against the inner wall by springs. In general, motors of this type have between three and ten vanes. The vanes form working chambers in the motor. The air enters in the smallest chamber and expands as the chamber enlarges. The effect of the air in these working chambers depends on the effective areas of the vanes.
  • Vacuum equipment uses vacuum pressure either from a vacuum generator or from its own venturi principle device built in.
  • The suction nozzle is used as a transport device in conjunction with a suction cup to move a variety of different components. It operates on the venturi principle (vacuum). Supply air is applied at inlet (P). The contraction in the diameter of the line increases the velocity of the air flowing toward (R), and a vacuum is generated at suction cup connection (A) (suction effect). In this manner, parts can be held and transported. A clean surface yields the best suction effect.
  • Page Industrial Pneumatic Fundamentals These shapes and lines in the relative proportions shown, make up a set of basic symbols from which fluid power symbols and circuits are constructed
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  • The dotted line represents the feedback, this opposes the spring and can vary the flow through the valve from full flow, through shut off, to exhaust. The symbol is usually drawn in only this one state. The flow path can be imagined to hinge at the right hand end to first shut off the supply then connect to the exhaust.
  • The dotted line represents feed-forward, this opposes the spring and can be imagined to lift the flow path. When the pressure reaches an excess value the flow path will line up with the ports and flow air to relief.
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  • The following circuit is an actual circuit being used to control a die to form a part of an automobile body. The intent of showing this circuit is as an example of how the air logic functions in the valves and how they must be visualized to trouble shoot a circuit. The notes in the following slides will provide a sequence of the operation of the circuit. Where would this descriptive sequence usually be found?
  • The blue lines indicate active air that is being applied, while exhaust air shown as normal circuit lines. There are air operated indicators located on the valve enclosure and they will be shown in their active state, either red or green. This slide is the beginning of the operation cycle. Note the current state of the valve logic blocks. As we proceed to the following slides the logic blocks will be shifted to show the active states of the valves. To begin the sequence remote switch operators will be selected OPEN or CLOSE to run the sequence. Note the two inputs of those operators at the top of the diagram.
  • To start the operational sequence air is applied to the “open” connection. Initially the air will pass through the Quick exhaust valve and through PV1, 2 and 3 to retract all cylinders. If the Limit valves LV1 and LV3 are in the correct position then the valves RV1, 2 and 4 will be shifted.
  • After RV1, 2 and 4 Shift then air is applied through RV1 to shift PV1. Cam A and B cylinders will extend. The green indicator will come on.
  • When Cam A and B cylinders begin to extend they will operate LV1 and LV3
  • As the Cam B cylinder continues its extension until it operates LV31.
  • When LV31 is operated by Cam B cylinder air is supplied to shift PV2. When PV2 is operated Cam C cylinder begins to extend. The green indicator will come on.
  • When all three cylinders Cam A, B and C are extended the three limit valves LV2, 4 and 6 will be operated. With limit valves LV2, 4 and 6 operated valves RV3 and PV3 will be operated. Cam C cylinder also will operate to open the limit valve LV5.
  • When PV3 operates the three Lifter cylinders will extend. The green indicator will come on.
  • When the Open sequence is done the remote input OPEN is turned off removing air from the circuit,
  • To start the close sequence air is applied to the CLOSE input. Initially the air applied will cause the green indicators to pop back on and the cylinders to remain extended. The quick exhaust valve will shift to prevent air from entering the OPEN line.
  • Air is applied through RV3 to operate the valves RV1, 2 and 4
  • With RV2 and RV1 operated air is applied to operate PV2 and PV3
  • With PV2 and PV3 operated air is applied to retract Cam C cylinder and the Lifter cylinders. The red indicators are on. When Cam C cylinder retracts LV5 is no longer operated and air is applied to operate PV1 through RV4.
  • With PV1 operated Cam A and Cam b cylinders are retracted.
  • With the close sequence completed air is removed from the CLOSE input. The limit valves should now be set to begin the OPEN sequence.
  • Transcript

    • 1. Industrial Pneumatic Fundamentals Pneumatic Fundamentals
    • 2. Objectives
      • Define States of Matter (with emphasis on liquids & gases and their effects on pneumatic equipment)
      • Define Fundamental Pneumatic Terms and concepts and constituents of air
      • Define Gas Laws
      • Define Force
      • Review Air Preparation
    • 3. Physical vs. Chemical State Change
      • Physical State Change
      • Chemical State Change
      Physical Change Of Water Into Ice Chemical Change Of Water Into Hydrogen Peroxide
    • 4. Physical States of Matter (See notes for definitions of each state) Gas, Liquid, Solid, Plasma, and Bose-Einsten Condensate (BEC) Cool or compress Cool Heat or reduce pressure Heat Total disorder; much empty space; particles have complete freedom of motion; particles far apart. Disorder; particles or clusters of particles are free to move relative to each other; particles close together. Ordered arrangement; particles are essentially in fixed positions; particles close together. Gas Liquid Crystalline solid
    • 5. Water – Changes of State A B C D F E 75 100 125 50 25 0 -25 Temperature ( ° C) Heat added (each division corresponds to 4kJ) Ice Ice and liquid water (melting) Liquid water Ice and liquid and vapor (vaporization) Water vapor
    • 6. Relative Humidity and Dew Point
      • What does this have to do with a pneumatic system?
      Temperature (degrees C) Water in Air (grams H 2 O per Kilogram of Air) Amount of Water in Air at 100% Relative Humidity Across a Range of Temperatures 100 = 100% Relative Humidity (Dew Point) = 50% Relative 10 90 80 60 70 30 40 50 0 10 20 40 50 0 -10 -20 20 30
    • 7. Pressure Fundamentals
      • Pressure – the force exerted by a fluid at rest per unit area on which the force acts.
      • Units – pound-force per square inch or psi (European unit is the bar; 1 bar = 14.5-psi).
      • Differential pressure – difference in pressure between two regions
    • 8. Pneumatic Terms
      • Standard Temperature Pressure (STP)
      • Normal air
      • Free air
      • Standard Cubic Feet per Minute (SCFM)
      • Relative Humidity
      • Dew Point
    • 9. Pneumatic Terms
      • Desiccant
      • Adsorption
      • Absorption
    • 10. Advantages / Disadvantages of Pneumatics
      • Advantages:
        • The working fluid (air) is abundant, readily available, inexpensive, cleaner, and safer to use than oil-based hydraulic fluids, and is less environmentally hazardous.
        • Return lines are unnecessary.
        • Due to the compressibility of air, pneumatic equipment is less likely to be damaged by overpressure conditions.
      • Disadvantages
        • Energy density is lower than hydraulics. Higher pressures are used in hydraulics, therefore the energy to move loads is available.
        • Pneumatic systems require bleeding pressure off to release a load, whereas in hydraulics a slight movement of the load releases the pressure.
    • 11. Constituents of (Free) Air
      • 78.084% Nitrogen (inert, and as a result, slows combustion of Oxygen)
        • 20.946% Oxygen (readily supports combustion)
        • 0.934% Argon
        • 0.038% Carbon Dioxide
        • 1% water Vapor
        • 0.002% other (Neon, Helium, Methane, Krypton, Hydrogen, Nitrous Oxide, Xenon, Ozone, Nitrogen Dioxide, Iodine, and trace amounts of Carbon Monoxide and Ammonia)
      • Total = 100.004 (due to rounding and does not include water vapor, which is contained in the air, not part of it)
    • 12. Characteristics of Gases vs. Liquids Gases expand to fill all of the available space, liquids do not.
    • 13. The Gas Laws
      • Bernoulli’s Principle
      • Boyle’s Law
      • Charles’ Law (principle)
      • General Gas Laws
    • 14. Gas Law Concepts
      • Assuming one of the three variables to be held at a constant value, we can look at the relationship between the other two for each case:
        • Constant temperature
        • Constant pressure
        • Constant volume
      For any given mass of air, the variable properties are pressure, volume and temperature. = P T constant V T = constant PV = constant
    • 15. Bernoulli’s Principle PSI PSI PSI PUMP In the small section pipe, velocity is maximum. More energy is in the form of motion, so pressure is lower. “in a system with a constant flow rate, energy is transformed from one form to the other each time the pipe cross-section size changes” Velocity decreases in the larger pipe. The kinetic energy loss is made up by an increase in pressure. Ignoring friction losses, the pressure again becomes the same as at “A” when the flow velocity becomes the same as at “A.” A B C
    • 16. Boyle’s Law
      • “if the temperature of a confined body of gas is maintained constant, the absolute pressure is inversely proportional to the volume.”
      P1 X V1 = P2 X V2 = P3 X V3 = constant where P = pressure and V= volume F1 F2 F3 V1 P1 V2 P2 V3 P3
    • 17. Constant Temperature 0 2 4 6 8 16 0 2 4 6 8 10 12 Volume V Pressure P bar absolute P1 · V1 = P2 · V2 = constant 10 12 14 14 16
    • 18. Constant Temperature 0 2 4 6 8 16 0 2 4 6 8 10 12 10 12 14 14 16 Volume V Pressure P bar absolute P1 · V1 = P2 · V2 = constant
    • 19. Constant Temperature 0 2 4 6 8 16 0 2 4 6 8 10 12 10 12 14 14 16 Volume V Pressure P bar absolute P1 · V1 = P2 · V2 = constant
    • 20. Constant Temperature 0 2 4 6 8 16 0 2 4 6 8 10 12 10 12 14 14 16 Volume V Pressure P bar absolute P1 · V1 = P2 · V2 = constant
    • 21. Charles’ Law
      • If heated by 1 K degree at constant pressure, air expands by 1/273 of its volume.
      • This is shown by Charles’ Law where:
    • 22. Constant Pressure 0 0.25 0.5 0.75 1 2 -60 -40 -20 0 20 40 60 Volume Temperature Celsius 1.25 1.5 1.75 80 100 293K V1 V2 T1 (K) T2 (K) = c =
    • 23. Constant Pressure 0 0.25 0.5 0.75 1 2 -60 -40 -20 0 20 40 60 Volume Temperature Celsius 1.25 1.5 1.75 80 100 366.25K V1 V2 T1 (K) T2 (K) = c =
    • 24. Constant Pressure 0 0.25 0.5 0.75 1 2 -60 -40 -20 0 20 40 60 Volume Temperature Celsius 1.25 1.5 1.75 80 100 219.75K V1 V2 T1 (K) T2 (K) = c =
    • 25. Constant Pressure 0 0.25 0.5 0.75 1 2 -60 -40 -20 0 20 40 60 Volume Temperature Celsius 1.25 1.5 1.75 80 100 366.25K 219.75K 293K V1 V2 T1 (K) T2 (K) = c =
    • 26. The Combined Gas Law The combined or general gas law is where pressure, volume and temperature may all vary between states of a given mass of gas but their relationship results in a constant value. = constant P 1 .V 1 T 1 P 2 .V 2 T 2 =
    • 27. Compressibility Review of Boyle’s Law For a fixed mass of ideal gas at fixed temperature, the product of pressure and volume is a constant.
      • VP = k
      • V 1 P 1 = V 2 P 2
    • 28. Compressibility – Charles Law
      • V/T = k
      • V 1 T 2 = V 2 T 1
      Review of Charles’ Law At constant pressure, the volume of a given mass of an ideal gas increases or decreases by the same factor as its temperature (in Kelvin) increases or decreases. -65 °C 250 °C
    • 29. Compressibility
      • pV = nRT (or for most conditions) V 1 T 2 = V 2 T 1
      • P 1 V 1 T 2 = P 2 V 2 T 1 or P 1 V 1 /T 1 = P 2 V 2 /T 2
      Review of General or Ideal Gas Laws The state of an amount of gas is determined by its pressure, volume, and temperature according to the equation:
    • 30. Compressibility
      • Conclusion – gases are easily compressible, liquids are not.
        • Gases – compressible roughly 1700 to 1
        • As gas pressure increases, temperature increases and volume decreases.
        • Liquids – roughly 1 to 1 (considered non-compressible)
    • 31. Pressure Scales Pressure in pneumatic systems is measured in one of three scales: absolute (psia), gauge (psig), and vacuum ("Hg). Gauge Pressure Vacuum-negative gauge Pressure Absolute Pressure Atmospheric Pressure Absolute Zero Absolute Pressure Pressure
    • 32. Measuring Atmospheric Pressure
      • Average sea level pressure = 101.325-kPa (kilopascals)1-kPa = 1-millibar
      • US reports atmospheric pressure in inches (hundredths of inches) of Mercury (& in mbar)
      • 101.32-mbar is reported as 132
      Atmospheric pressure facts: 29.92” Sea Level Atmospheric Pressure Barometer
    • 33. Atmospheric Pressure Atmospheric pressure values are displayed on weather maps.
      • Lines (called isobars) show contours of pressure in millibars.
      • Lines help predict wind direction and force.
      LOW 101.5 mb 101.2 mb 100.8 mb 100.0 mb 996.0 mb
    • 34. Pressure at Various Altitudes 10.0 20.4 10000 10.4 21.2 9000 10.8 22.1 8000 11.2 22.9 7000 11.7 23.8 6000 12.1 24.7 5000 12.6 25.7 4000 13.1 26.7 3000 13.6 27.7 2000 14.2 28.8 1000 14.7 29.92 0 Approx. Atmospheric Pressure in pounds per square inch (PSI) Barometer Reading in Inches of Mercury Altitude above sea level in Feet
    • 35. ″Hg / PSI Conversions
      • Example : ″Hg to PSI
      • 10 ″Hg x 0.491 = 4.91-psia
      • 29.92 ″Hg x 0.491 = 14.69-psia
      • Example: PSI to ″Hg
      • 14.7-psia / 0.491 = 29.93 ″Hg
      • 10-psia / 0.491 = 20.36 ″Hg
      • Remember:
      • PSIA = PSIG + 14.7
      • PSIG = PSIA – 14.7
      PSIG Vacuum 5” 10” 15” 20” 25” 29.92” Sea Level Atmospheric Pressure 5 3 1 Mercury Column Height X 0.491 = P.S.I.
    • 36. Comparing ″Hg Vacuum to ″Hg Absolute ″ Hg absolute measures atmospheric pressure (determined by how high a column of mercury the pressure will cause) ″ Hg vacuum measures pressure below atmospheric pressure Absolute Pressure Scale 0 5 10 15 20 25 30(29.92) Vacuum Pressure Scale 30(29.92) 25 20 15 10 5 0 In. Hg. Abs. Pressure In. Hg. Vacuum
    • 37. Pressure Scales
      • Either of two pressure scales are used to measure pressure — an absolute scale or a gage scale.
      Absolute Pressure Scale 29.7 Gauge Pressure Scale 24.7 19.7 14.7 11.0 7.35 3.67 0 0 7.5 14.9 22.4 29.92 0 5 10 15 PSIA In. Hg. Abs. Press. PSIG
    • 38. Pressure Ranges
    • 39. Gage Operation (Plunger Gage) 0 5000 3000 4000 2000 1000 psig Pivot Pointer Fluid In Plunger Bias Spring Plunger Gage
    • 40. Gage Operation (Bourdon Tube) Bourdon tube Fluid in Linkage Needle Pointer Bourdon Tube 0 5000 1000 1500 2000 2500 3000 Absolute Pressure + 14.7 P.S.I. Gage Reading =
    • 41. Gage Reading Basics
      • Reading accuracy – gages may be read to one-half of the smallest increment.
      • Make sure equipment is depressurized before opening system or performing maintenance .
    • 42. Vacuum Gage 0 15 25 20 30 5 10 Vacuum Gage Vacuum in Hg. Absolute Pressure = 30 - Vacuum Reading
    • 43. Pneumatic Transmission of Energy
      • Pneumatics energy is used to perform work.
      • Energy is stored in the form of compressed air and the energy is released when the air is allowed to expand.
      • A device is needed (an air compressor) to supply compressed air at a desired pressure.
      • A cylinder is one type of device that can be used to convert the stored energy into work.
    • 44. Force Transmission Through a Solid Solid Movable Piston
    • 45. Force Transmission Through a Liquid
    • 46. Force Transmission Through a Gas
    • 47. Measuring Fluid Performance
      • Pascal’s Law simply stated says: “Pressure applied on a confined fluid is transmitted undiminished in all directions, and acts with equal force on equal areas, and at right angles to the surface.”
      Pressure exerted by fluid equal in all directions
    • 48. Force Transmission Through a Fluid – Pascal’s Law Pascal’ s Law (principle) LBS
    • 49. Force Transmission Through a Fluid 1000 lbs. Object of resistance 100 psi. 100 psi. 100 psi. 1500 lbs. Piston area 10 sq. in. Piston area 15 sq. in.
    • 50. Definition of Pressure
      • Definition of pressure: If F is the magnitude of the normal force on a piston and A is the surface area of a piston, then the fluid pressure, P, is the ratio of the force to area.
      Pressure in PSI (pounds per square inch) if Force in in pounds (lbs) and area is in square inches. F P A
    • 51. Primary/Secondary Air Treatment
      • Secondary air treatment – conditioning of air at or near the point of usage.
      • Conditioning equipment :
        • Filters
        • Lubricators
        • Regulators
      Primary air treatment – conditioning of air before, during, and after compression; but before distribution.
    • 52. Compressed Air System Tank Motor Compressor Gauge
    • 53. Regulator Drawing Symbol Diaphragm Spring Adjusting Screw Valve Seat Damping spring Valve disc Vent hole
    • 54. Air Filter
      • An in-line air filter collects and retains contaminants.
      Drawing Symbol Air In Air Out Filter bowl Baffle plate Filter Drain
    • 55. Lubricators Inlet Outlet Valve Drip Duct Check Valve Drip Chamber Duct Oil passage Drawing Symbol
    • 56. Venturi Principle
      • The pressure difference Δp (pressure gradient) between the pressure in front of the air nozzle and the pressure at the smallest section of the nozzle is used to draw liquid (oil) from a container and to mix it with the air.
      Δp
    • 57. FRL Drawing Symbol Filter Regulator and Gauge Lubricator
    • 58. Types of Compressors Piston Compressor Diaphragm Compressor Types of Compressors Reciprocating piston Compressors Rotary piston Compressors Flow Compressors Radial flow Compressor Axial flow Compressor Sliding vane rotary Compressor Two axle Compressor Lobe type Compressors
    • 59. Reciprocating Piston Compressor
    • 60. Diaphragm Compressor
    • 61. Sliding Vane Rotary Compressor
    • 62. Screw Compressor
    • 63. Lobe Compressor
    • 64. Axial-Flow Compressor
    • 65. Radial Flow Compressor
    • 66. Summary
      • Review Objectives
      • Question and Answer Session
    • 67. Industrial Pneumatic Fundamentals Pneumatic Controls and Devices
    • 68. Objectives
      • Define types of pneumatic valves and symbols
      • Define types of logic valves and symbols
      • Define pneumatic actuators and symbols
      • Define piston force
      • Define pneumatic motors and symbols
    • 69. Pneumatic Valves
      • The basic function of valves is to switch air flow
      • The range of pneumatic valves is vast
      • To help select a valve they are placed in a variety of categories:
        • style
        • type
        • design principle
        • type of operator
        • function
        • size
        • application
    • 70. Style
      • Style reflects the look of a valve range as well as the underlying design principle
    • 71.
      • Type refers to the valves installation arrangement for example sub-base, manifold, in line, and valve island
      Type
    • 72.
      • Design refers to the principle of operation around which the valve has been designed, for example, spool valve, poppet valve and switch or plate valves.
      Design
    • 73. Valve Operators Shrouded Button Mushroom Button Twist Push Button Key Operated Switch Key Released Solenoid Pilot Roller Air Pilot Plunger Emergency Stop
    • 74. Operator Symbols - Manual General manual Push button Pull button Push/pull button Lever Pedal Treadle Manual Rotary knob
    • 75. Operator Symbols - Mechanical Mechanical Plunger Spring normally as a return Roller Uni-direction or one way trip Pressure Pilot pressure Differential pressure Detent in 3 positions
    • 76. Operator Symbols - Electrical Solenoid direct Solenoid pilot Solenoid pilot with manual override and integral pilot supply Solenoid pilot with manual override and external pilot supply Electrical When no integral or external pilot supply is shown it is assumed to be integral
    • 77. Valve Function
      • Function is the switching complexity of a valve
      • This function is shown by two figures 2/2, 3/2, 4/2, 5/2, 3/3, 4/3 & 5/3
    • 78. Valve functions 5/3
      • Three position valves have a normal central position that is set by springs or with a manual control such as a lever
      • The flow pattern in the centre position varies with the type. Three types will be considered
      • 1, All ports sealed
      • 2, Outlets to exhaust, supply sealed
      • 3, Supply to both outlets, exhausts sealed
    • 79. 2 Position, 5 Port Valve Control Input to Valve Input 14 14 4 2 12 5 1 3 1 4 2 12 3 5 14
    • 80. 2 Position, 5 Port Valve 1 4 2 12 3 5 14 Control Input to Valve Input 12 14 4 2 12 5 1 3
    • 81. Valve Size
      • Size refers to a valve’s port thread.
      • The port size progression M5, R 1 / 8 , R 1 / 4 , R 3 / 8 , R 1 / 2 , R 3 / 4 , R1.
      M5 R 1 / 8 R 1 / 4 R 3 / 8 R 1 / 2 R 3 / 4 R1
    • 82. Application
      • Application is a category for valves described by their function or task
      • Examples of specialist valves are quick exhaust valve, soft start valve and monitored dump valve
      • Examples of standard valves are power valves, logic valves, signal processing valves and fail safe valves
      • A standard valve could be in any category depending on the function it has been selected for in a system
    • 83. Other Valve Designs
      • Shut off Valves
      • Limit Switches
      • Selector Switches
      • Pressure Switches
      • Flow Regulators/Control
      • Quick Exhaust
      • AND / OR Valves
    • 84. Shutoff Valves Drawing Symbol
    • 85. Limit Switch Valves 1 2 12 10 1 3 1 2 3 1 3 2
    • 86. Selector Switch Valves 1 2 3 4 2 4 1 2 4 3 1 3 1 2 3 4
    • 87. Pressure Switch (pneumatic)
      • Relay to boost weak signals
      • Relay for a pneumatic time delay
      • When the signal at port 12 reaches about 50% of the supply pressure at port 1, the pressure switch operates to give a strong output signal at 2
      • For time delays at any pressure only the linear part of the curve will be used giving smooth adjustment
      1 3 12 10 1 2 3 12 10 1 2 3 12 10
    • 88. Pressure Switches Off Actuated 1 2 3 12 1 2 3 12 10 1 2 3 12 1 2 3 12 10
    • 89.
      • This example uses a built in single acting cylinder to operate a standard changeover microswitch
      • The operating pressure needs to overcome the combined force of the cylinder and microswitch springs
      • Adjustable pressure switches are also available allow adjustment to the operating pressure
      Pressure Switch - Electrical Fixed Adjustable
    • 90. Flow Regulator
    • 91. Flow Regulation for Speed
    • 92. Quick Exhaust Valve Symbol Circuit example 1 2 2
    • 93. Air Logic
      • In the age of microchips and personal computers, air logic can still provide an effective, efficient, and inexpensive means of control for certain pneumatic machines.
      • Air logic controls can perform any function normally handled by relays, pressure or vacuum switches, time delays, limit switches, and counters. The circuitry is similar, but compressed air is the control medium instead of electrical current.
    • 94. Logic “OR” Shuttle Valve 1 3 2 1 3 3 1 2 3 ≥ 1 1 2 3
    • 95. Logic “AND” Shuttle Valve 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 Popular old symbol 1 2 3 ISO symbol & 1 2 3
    • 96. Two Hand Anti-tie Down 1 2 3 SYMBOL Timing Chamber OR gate – 1 or 2 passes to timing 2 enables 1 to pass to 3 or output When timing done will block input air from output if not present already
    • 97. Timers INPUT OUTPUT Positive Timer Symbol Positive Timer Example Negative Timer Symbol ON INPUT OFF ON OUTPUT OFF TIME DELAY
    • 98. One Shot Timer A A Logic symbol ANSI symbol
    • 99.
      • Pneumatic actuators include linear cylinders and rotary actuators.
      • They are devices providing power and motion to automated systems, machines and processes.
      • A pneumatic cylinder is a simple, low cost, easy to install device that is ideal for producing powerful linear movement.
      • Speed can be adjusted over a wide range.
      • A cylinder can be stalled without damage.
      Actuators
    • 100.
      • Adverse conditions can be easily tolerated such as high humidity, dry and dusty environments and cleaning down with a hose.
      • The bore of a cylinder determines the maximum force that it can exert.
      • The stroke of a cylinder determines the maximum linear movement that it can produce.
      • The maximum working pressure depends on the cylinder design. Thrust is controllable through a pressure regulator.
      Actuators
    • 101. Basic Construction Cylinder Barrel Base Cap Bearing Cap Piston Rod Packing ring Bushing Wiper Construction of a pneumatic cylinder with end position cushioning Seals Piston
    • 102.
      • Pneumatic actuators are made in a wide variety of sizes, styles and types including the following
      • Single acting with and without spring return
      • Double acting
        • Non cushioned and fixed cushioned
        • Adjustable cushioned
        • Magnetic
      • Rodless
      • Rotary
      • Clamping
      • Bellows
      Some Fundamental Designs
    • 103. Piston Force Cylinder Piston Piston Rod Cylinder Piston Piston Rod D D D
    • 104. Example of Cylinder Force
      • A cylinder with a 4 inch diameter and 1.5 inch cylinder rod diameter with air pressure of 80 psi (pounds per square inch).
        • Area = 12.6 sq in.
        • Area of rod end = 1.8 sq in.
        • Force = 80 X (12.6 – 1.8) = 864 lbs on retract of cylinder.
        • Force = 80 X 12.6 = 1008 lbs on extend of cylinder.
    • 105.
      • An air take up is used to keep a chain conveyor from becoming slack due to load changes. This is a common application to production chains a mile long in automobile plants.
      • If a take-up cylinder has a 12 inch diameter and 3 inch cylinder rod diameter and the chain pull has been determined to be 2225 pounds then what should the air pressure be set to.
      • The pull is at the rod end.
      • Use Pressure = Force ÷ Area
      Force Of A Take-up Air Cylinder
    • 106. Cylinder Force Table 2,827 2,545 2,262 1,696 1,414 1,131 848.1 565.4 282.7 28.27 6 1,963 1,767 1,571 1,178 982 785 588.9 392.6 196.3 19.63 5 1,257 1,131 1,005 754 628 503 377.1 251.4 125.7 12.57 4 830 747 664 498 415 332 249 166 83 8.3 3.25 491 442 393 295 245 196 147.3 98.2 49.1 4.91 2.5 314 283 251 188 157 126 94.2 62.8 31.4 3.14 2 177 159 141 106 88 71 53.7 35.4 17.7 1.77 1.5 79 71.1 63.2 47.4 17.4 31.6 23.7 15.8 7.9 0.79 1 44 39.6 35.2 26.4 22 17.6 12 8.8 4.4 0.44 0.75 100 90 80 60 50 40 30 20 10 PRESSURE (PSI) Piston Area (in) Bore (in) CYLINDER FORCE TABLE (Pounds)
    • 107. Cylinder Rod Force Deduction Chart 706.8 636.12 565.44 424.08 353.4 282.72 212.04 141.36 70.68 7.068 3 148.5 133.65 118.8 89.7 74.25 59.4 44.55 29.7 14.85 1.485 1.375 78.5 70.65 62.8 47.1 39.25 31.4 23.55 15.7 7.85 0.785 1 44.1 39.69 26.46 26.46 22.05 17.64 13.23 8.82 4.41 0.441 0.75 30.7 27.63 24.56 18.42 15.35 12.28 9.27 6.14 3.07 0.307 0.625 19.6 17.64 15.68 11.76 9.8 7.84 5.88 3.92 1.96 0.196 0.5 4.9 4.41 3.92 2.94 2.45 1.96 1.47 0.98 0.49 0.049 0.25 100 90 80 60 50 40 30 20 10 PRESSURE (PSI) Rod Area (in) Rod (in) Cylinder Rod Force Deduction Chart
    • 108. Cylinder Speed
      • Finally calculate the flow rate CFM (cubic feet per minute) needed to move the load
      • Volume is V = A x S
      • Compression Ratio
    • 109. Actuators
      • Cylinders symbols can be any length.
      • The piston and rod can be shown in the retracted, extended or any intermediate position
    • 110. Single Acting
      • Normally in
      • Normally out
    • 111. Double Acting Piston Piston Rod
    • 112. Double Ended
    • 113. Cylinder Mounting Foot Mounted Thread Mounted Front Flange Rear Flange Swivel Flange Front Swivel Flange Center Swivel Flange Rear
    • 114. Air Motors Advantages
      • Advantages
        • Do not require electric power
        • Smaller than electric motors
        • Do not need reducers
        • Simple regulation using flow controls
        • Torque varied by regulating pressure
        • Do not need relays or motor controllers
        • Do not generate much heat
    • 115. Air Motor Disadvantages
      • Disadvantages
        • Cost can exceed an electric motor
        • Cost of operating can be greater
        • Speed control not as accurate
        • Plant air variations cause speed and torque fluctuations
    • 116. Piston Air Motors Motor Single Direction Symbol Motor Bi-directional Symbol
    • 117. Vane Motors Motor Single Direction Symbol Motor Bi-directional Symbol
    • 118.
      • Vacuum generator
      Vacuum Equipment Vacuum cups Vacuum switch pneumatic NO NC Vacuum filter Vacuum silencer Vacuum gauge 1 2 3 2 1 3
    • 119. Vacuum Cup P R A Orifice that generates vacuum or suction via the venturi principle
    • 120. Summary
      • Review Objectives
      • Question and Answer Session
    • 121. Industrial Pneumatic Fundamentals Pneumatic Symbols and Drawings
    • 122. Objectives
      • Define Industry Standards used for Industrial Electrical Drawings.
      • Define Pneumatic Diagrams or Drawings and how they are structured.
      • Define Pneumatic Symbols and logic applied to pneumatic drawings.
    • 123. Standards
      • STANDARDS ARE IMPORTANT FOR THE FOLLOWING REASONS.
        • · Components must be interchangeable and must perform to known standards. This includes actuators, valves and pipe fittings.
        • · Symbols must be interpreted the same way by any competent person so that they can follow a circuit diagram and install them correctly.
        • · Drawings layouts and drawing symbols must be interpreted the same way by any competent person and this involves both circuit and layout drawings.
        • · There are many other standards concerning things such as health and safety, hydraulic fluids and filters.
        • There are various organizations devoted to producing standards in the field of fluid power.
    • 124. Shapes
      • Shapes and lines that are used to construct symbols and circuits:
    • 125. Basic Symbols (shapes) Circles energy conversion units measuring instrument mechanical link roller
    • 126. Basic Symbols (shapes) Square at 45 o conditioning apparatus connections to corners Square control component connections perpendicular to sides Rectangle cylinders and valves
    • 127. Basic Symbols (shapes) certain control methods Rectangles cushion piston
    • 128. Basic Symbols rotary actuator, motor or pump with limited angle of rotation Semi-circle mechanical connection piston rod, lever, shaft Double line Capsule pressurised reservoir air receiver, auxiliary gas bottle
    • 129. Basic Symbols Line Working line, pilot supply, return, electrical Chain Enclosure of two or more functions in one unit Dashed Pilot control, bleed, filter Line Electrical line 1 2 3 12 10
    • 130. Functional Elements Long sloping indicates adjustability Arrow Spring Triangle Direction and nature of fluid, open pneumatic or filled hydraulic
    • 131. Functional Elements Straight or sloping path and flow direction, or motion Arrows Restriction Tee Closed path or port
    • 132. Functional Elements 90 o angle Seating rotary motion Curved arrows clockwise from right hand end Shaft rotation anti-clockwise from right hand end both
    • 133. Functional Elements Indication or control size to suit Temperature Operator Opposed solenoid windings Prime mover M Electric motor M
    • 134. Flowlines not connected Crossing Junction Single Hose usually connecting parts with relative movement Flexible line Junction Four way junction
    • 135. Connections Continuous Air bleed Air exhaust No means of connection Temporary by probe With means of connection
    • 136. Connections Both to exhaust Coupling quick release Coupling quick release self sealing Source sealed Coupling quick release self sealing Both sealed
    • 137. Connections Rotary connection one line Rotary connection two lines Rotary connection three lines
    • 138. Function components Silencer Pressure to electric switch preset Pressure to electric switch adjustable
    • 139. Function components Uni-directional flow regulator Rotating joint Pressure indicator Pressure drop indicator
    • 140. Plant Air receiver Isolating valve Air inlet filter Compressor and electric motor M
    • 141. Combination units
      • FRL with shut off valve and pressure gauge
      Lubro-control unit Filter and lubricator FRL Combined unit Filter regulator with gauge
    • 142. Filters
      • Filter with manual drain
      Filter with automatic drain Filter with automatic drain and pressure drop indicator
    • 143. Pressure regulators
      • A pressure regulator symbol represents a normal state with the spring holding the regulator valve open to connect the supply to the outlet.
      Adjustable Regulator with pressure gauge simplified Adjustable Regulator simplified
    • 144. Pressure relief valves
      • A pressure relief valve symbol represents a normal state with the spring holding the valve closed.
      Adjustable relief valve simplified Preset relief valve simplified
    • 145. Pressure regulators
      • Pre-set relieving
      Adjustable relieving Adjustable relieving with pressure gauge Pre-set relieving with pressure gauge
    • 146. Valve symbol structure
      • The function of a valve is given by a pair of numerals separated by a stroke, e.g. 3/2..
      • The first numeral indicates the number of main ports. These are inlets, outlets and exhausts but excludes signal ports and external pilot feeds.
      • The second numeral indicates the number of states the valve can achieve.
    • 147. Valve symbol structure
      • A 3/2 valve therefore has 3 ports (normally these are inlet, outlet and exhaust) and 2 states (the normal state and the operated state)
      • The boxes are two pictures of the same valve
      normal operated
    • 148.
      • Valve switching positions are illustrated with squares on a schematic.
      • The number of squares is used to illustrate the quantity of switching positions.
      • Lines within the boxes will indicate flow paths with arrows showing the flow direction.
      • Shut off positions are illustrated by lines drawn at right angles to the flow path.
      • Junctions within the valve are connected by a dot.
      • Inlet and outlet ports to the valve are shown by lines drawn to the outside of the box that represents the normal or initial position of the valve
      Basic Valve Symbology
    • 149. Valve symbol structure
      • A valve symbol shows the pictures for each of the valve states joined end to end
      normal operated
    • 150. Valve symbol structure
      • A valve symbol shows the pictures for each of the valve states joined end to end
      normal operated
    • 151. Valve symbol structure
      • The port connections are shown to only one of the diagrams to indicate the prevailing state
      normal
    • 152. Valve symbol structure
      • The operator for a particular state is illustrated against that state
      Operated state produced by pushing a button
    • 153. Valve symbol structure
      • The operator for a particular state is illustrated against that state
      Operated state produced by pushing a button Normal state produced by a spring
    • 154. Valve symbol structure
      • The operator for a particular state is illustrated against that state
      Operated state produced by pushing a button Normal state produced by a spring
    • 155. Valve symbol structure
      • The valve symbol can be visualised as moving to align one state or another with the port connections
    • 156. Valve symbol structure
      • The valve symbol can be visualised as moving to align one state or another with the port connections
    • 157. Valve symbol structure
      • The valve symbol can be visualised as moving to align one state or another with the port connections
    • 158. Valve symbol structure
      • A 5/2 valve symbol is constructed in a similar way. A picture of the valve flow paths for each of the two states is shown by the two boxes. The 5 ports are normally an inlet, 2 outlets and 2 exhausts
    • 159. Valve symbol structure
      • The full symbol is then made by joining the two boxes and adding operators. The connections are shown against only the prevailing state
    • 160. Valve symbol structure
      • The full symbol is then made by joining the two boxes and adding operators. The connections are shown against only the prevailing state
    • 161. Valve symbol structure
      • The full symbol is then made by joining the two boxes and adding operators. The connections are shown against only the prevailing state
    • 162. Valve symbol structure
      • The boxes can be joined at either end but the operator must be drawn against the state that it produces. The boxes can also be flipped
      • A variety of symbol patterns are possible
      normally closed normally open
    • 163. Valve functions 5/3
      • Three position valves have a normal central position that is set by springs or with a manual control such as a lever
      • The flow pattern in the centre position varies with the type. Three types will be considered
      • 1, All ports sealed
      • 2, Outlets to exhaust, supply sealed
      • 3, Supply to both outlets, exhausts sealed
    • 164. Valves 5/3 All valves types shown in the normal position Type 1. All ports sealed Type 2. Outlets to exhaust Type 3. Supply to outlets
    • 165. Valves 5/3 All valves types shown in the first operated position Type 1. All ports sealed Type 2. Outlets to exhaust Type 3. Supply to outlets
    • 166. Valves 5/3 All valves types shown in the second operated position Type 1. All ports sealed Type 2. Outlets to exhaust Type 3. Supply to outlets
    • 167. Operators General manual Push button Pull button Push/pull button Lever Pedal Treadle Manual Rotary knob
    • 168. Operators Mechanical Plunger Spring normally as a return Roller Uni-direction or one way trip Pressure Pilot pressure Differential pressure Detent in 3 positions
    • 169. Operators Solenoid direct Solenoid pilot Solenoid pilot with manual override and integral pilot supply Solenoid pilot with manual override and external pilot supply Electrical When no integral or external pilot supply is shown it is assumed to be integral
    • 170. Port markings The valve connections can be labelled with capital letters or numbers as follows: 12, 14, 16, 18… Z, Y, X ………………….. Pilot Lines 3, 5, 7 …… R, S, T ………………..W Exhaust 1 P ………………………… Supply Air 9 L ………………………… Leakage Fluid 2, 4, 6 . . . . A, B, C …….. O (excludes L) Working Lines Numerical Designations Alphabetical Designations
    • 171. Port Markings 1 2 12 10 1 2 4 5 3 14 12 1 2 4 3 14 12 1 2 3 12 10
    • 172. Port Markings 1 2 12 10 1 2 4 5 3 14 12 1 2 4 3 14 12 1 2 3 12 10
    • 173. Actuators
      • Cylinders symbols can be any length.
      • The piston and rod can be shown in the retracted, extended or any intermediate position
      “ l”
    • 174. Rotary actuators
      • Semi rotary double acting
      Rotary motor single direction of rotation Rotary motor bi-directional
    • 175. Simplified cylinder symbols
      • Single acting load returns
      Single acting spring returns Double acting non cushioned Double acting adjustable cushions Double acting through rod
    • 176. Sample Pneumatic Drawing ITEM DESCRIPTION QTY . I.D. SPECIFICATION 1 2 3 4 5 6 7 8 DWG. NO. Drawn: Checked Scale Installation Air Cylinder Flow Control A1 1 REX C23-7600 2/5 DC Valve Safety Shut Off Shut Off Valve Silencer Regulator and Gauge Filter 1 2 1 3 2 1 1 V1 FV1,2 V2 S1,2 R1 F1 SV1,2,3 NG-7124/3/8 NG-7128/3/8 NGS-7126/3/8 NG-7129/3/8 S-407/3/8 R-88/3/8 F-88/3/8 Cyl. A1 V1 FV1 FV2 V2 S2 S1 R1 F1 SV3 SV1 SV2 1 2 3 3 4 5 5 5 8 7 6 6 Track Switch AD003 T. Smith Jones None
    • 177. Summary
      • Review Objectives
      • Question and Answer Session
    • 178. Example Pneumatic Circuit Industrial Pneumatic Fundamentals
    • 179. Objective
      • To demonstrate and explain the reading of pneumatic drawings by way of example.
    • 180. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN AIR APPLIED TO OPEN INPUT START OF DIE OPEN SEQENCE – LV1 , LV3 AND LV5 ARE CLOSED – LV31, LV2, LV4, LV6 ARE OPEN SHUTTLE BALL BLOCKS CLOSE INPUT LINES
    • 181. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN RV1, RV2 and RV44 SHIFT WITH L1 AND L3 CLOSED
    • 182. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN PV1 SHIFTS WITH L1 AND L3 CLOSED AND RV1 SHIFTED ‘ A’ and ‘B’ CYLINDERS BEGIN EXTENDING
    • 183. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN LV1 AND LV3 OPEN WHEN A AND B CYLINDERS BEGIN MOVEMENT
    • 184. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN LV31 CLOSES OPEN WHEN AS B CYLINDER CONTINUES MOVEMENT
    • 185. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN PV2 SHIFTS WITH L31 CLOSED ‘ C’ CYLINDER EXTENDS
    • 186. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN LV2, LV4, LV6 CLOSE WHEN ALL THREE CYLINDERS ARE EXTENDED AND LV5 OPENS
    • 187. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN RV3 AND PV3 SHIFTS WITH L2, L4 AND L6 CLOSED LIFTER CYLINDERS EXTEND
    • 188. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN END OF DIE OPEN SEQENCE – OPEN AIR INPUT OFF – LV 2, LV4, LV6, LV31 ARE CLOSED AND LV1, LV3 AND LV5 ARE OPEN
    • 189. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN START OF CLOSE DIE SEQENCE – AIR INPUT TO CLOSE PORT AIR IS APPLIED TO CLOSE INPUT – SHUTTLE BALL SHIFTS TO BLOCK AIR FROM OPEN LINES
    • 190. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN RV1, RV2 AND RV4 ARE OPERATED
    • 191. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN PV1 AND PV3 ARE OPERATED
    • 192. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN LV5 CLOSES WHEN ‘C’ CYLINDER RETRACTED RV3 AND PV1 OPERATE
    • 193. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN ‘ A’ AND ‘B’ CYLINDERS RETRACT ALL CYLINDERS RETRACTED: LV 1 AND LV3 ARE CLOSED; LV2, LV4, LV6 AND LV31 ARE OPEN
    • 194. R G R G R G PV1B INITIAL CAMS CLOSED PV1A INITIAL CAMS OPEN PV2B SECONDARY CAMS CLOSED PV2A SECONDARY CAMS OPEN CAM A CYLINDER CAM B CYLINDER CAM C CYLINDER LIFTER CYLINDERS PV3B LIFTERS DOWN PV3A LIFTERS UP PV1 PV2 PV3 RV1 RV3 RV2 RV4 LV3 LV1 LV31 LV2 LV4 LV6 LV5 CAM C CAM A CAM B CAM C CAM B CAM A CAM B BH3 BH1 BH5 AIR CLOSE BH4 CONSTANT AIR CLOSE OPEN END OF CLOSE DIE SEQENCE AIR REMOVE FROM CLOSE INPUT– RETURN TO START OF OPEN SEQUENCE
    • 195. Summary
      • Review Objectives
      • Question and Answer Session

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