2. PUMPS
The pump is a mechanical device which conveys liquid from one place to another
place.
It can be defined as a hydraulic machines which converts mechanical energy into
hydraulic energy.
The pump is power absorbing machine.
Pumps are used for various applications in various fields as follow :
1. Thermal engineering
2. Agriculture & irrigation
3. Chemical industries
4. Muncipal water works and drainage system
5. Hydraulic control system
4. RECIPROCATING PUMP
Single Acting Reciprocating Pump :
In this pump liquid acts on one side
of the piston only. Suction as well as delivery takes place at
alternate stroke on the same side of the cylinder.
5. Double Acting Reciprocating Pump :
In this pump liquid acts on
both the sides of the piston. Suction and delivery strokes occur
simultaneously on the opposite sides of piston.
6. CENTRIFUGAL PUMP
If mechanical energy is converted into pressure energy by means
of centrifugal force acting on the fluid, for conveying liquids from
one place to other such device is called centrifugal pump.
7. TYPES OF CENTRIFUGAL PUMP
VOLUTE OR SPIRAL CASING TYPE PUMP
VORTEX OR WHIRLPOOL CHAMBER TYPE PUMP
DIFFUSER TYPE (casing with guide blades) PUMP
8. VOLUTE TYPE PUMP
In this type of centrifugal pump, impeller is surrounded by the
spiral casing known as volute chamber. Volute chanber provides a
gradual increase in area to the discharge pipe.
9. VORTEX TYPE PUMP
This vortex type of pump is modified type of volute casing. In this
casing, circular chamber is inserted between the impeller and
volute chamber and is formed a combination of spiral and circular
chamber. This chamber is known as vortex or whirlpool chamber
10. DIFFUSER TYPE PUMP
In this pump, the impeller is surrounded by a series of guide
blades mounted on a ring which is known as diffuser. The liquid
leaving the impeller flows through diffuser. The diffuser type pump
has higher efficiency. These pumps are also called turbine pumps.
11. PRIMING OF A CENTRIFUGAL PUMP
The priming is an operation of filling passage ways (suction pipe,
casing and delivery pipe upto delivery valve) from outside source
with the liquid to be raised before starting the pump.
12. The priming is positive displacement pumps (reciprocating pump)
is required only at the time of first starting. In this case priming
means filling liquid in casing and aim to diminish the clearance
volume. After first priming, it creates necessary vacuum for a total
lift without further priming. It can be removed the air by their own
pumping action. This is called Self priming.
13. ROTARY PUMPS
Rotary pump are positive displacement pumps. It consist of a
fixed casing with a rotor which may be in the form of gears, vanes,
lobes, screws, cams etc. Although both the centrifugal and rotary
pumps work by circular motion of rotor, but they work on different
principles. The centrifugal pump operates on principle of
centrifugal action of rotation, the pressure is developed by the
centrifugal action of liquid while rotary pumps operates similar to
reciprocating pump, the pressure is developed by positive
displacement of the liquid. Rotary pump is suitable for pumping
viscous fluids like vegetable oil, lubricating oil, alcohol, grease,
tar etc
15. GEAR PUMPS
Gear pump consists of two or more gears which mesh each other.
The rotation of these gears provides pumping action. Spur, helical,
herringbone type or gear may be used for the purpose but the spur
gear are most commonly used.
16. VANE PUMPS
The vane pumps consists of stationary casing and a cylindrical
rotor. The cylindrical rotor contains the sliding vanes which fitted
to the radial grooves of rotor. The rotor is mounted eccentrically
in relation to cylinder casing.
17. SCREW PUMPS
Screw pumps are special type of rotary positive displacement
pumps. It consists of pair of screws, one of the screw rotor drives
other screw rotor in the stationary casing. The liquid is carried
between screw threads in pair of screw mwsh and is displaced
axially as the screws rotates.