SlideShare a Scribd company logo
1 of 42
Pressure
measurementMITESH KUMAR
Rall no-10300513026
Applied Electronics & Instrumentation Engg.
Haldia Institute Of Technology
Density
D=M⁄V
So for greater density mass will more in the
substance in unit volume. And greater density
will give more hydrostatic(head) pressure than
lower density.
Density always define in given temperature
because density of a liquid decreases as
temperature increases.
This temperature is here reference temp.
Specific gravity
• Some time density can define in terms of Specific
gravity.
• Specific gravity is the ratio of the density of a
particular liquid to the density of water at a
reference temperature.
problem:
Water has a density of 1,000 kg/m3 at 50 °F. The
density of gasoline is 660 kg/m3 at 50 °F.
calculate Specific gravity of gasoline?
• Ullage Pressure is pressure that is exerted on the surface of a
liquid.
• In an open tank, atmospheric pressure (the pressure exerted by
the Earth’s atmosphere) is the pressure on the surface.
• A gauge pressure measurement is sufficient for level
measurement.
• In a closed tank, it is common practice to fill the vapor space with
buffer gas. This is done in order to protect the products inside the
tank or to prevent them from evaporating into atmosphere.
• This buffer gas will exert a pressure on the column of liquid that
must be subtracted from the measurement of the height of the
liquid column otherwise error will occur.
• Differential pressure measurement, where the low side reference
leg is connected to the vapor space will allow the head pressure to
be subtracted out.
Ullage Pressure
Factors for gas
• Factors for gas’s exert pressure
⇨ Gas container volume
⇨ Gas temperature.
There is ideal gas law relating it’s pressure
temperature and volume.
PV= nRT
Relations between
gas pressure and volume
Boyel’s law : It is stated that that the pressure and volume
of a gas have an inverse relationship, when temperature is
held constant.
P1V1= P2V2
A fixed amount of gas is transferred to a larger container,
the pressure will decrease in proportion to the increase in
container volume.
So we can conclude that gas can be compressed, the
pressure of a gas increases proportionately as the volume
of the container in which it is held decreases.
Need of pressure measurement
• There are four common need
⇨ Safety
⇨ Process efficiency
⇨ Cost savings
⇨ Measurement of other process variables
Safety
• Pipes, tanks, valves, and other equipment used with pressurized
fluids in process industries are designed to withstand the stress of a
specific range of pressures.
• Accurate pressure measurement and precise control help prevent
pipes and vessels from bursting.
• In addition, pressure measurement and control help minimize
equipment damage, reduce the risk of personal injury, and prevent
leaks of potentially harmful process materials into the environment.
• Pressure measurement used to control the level and flow of
process materials helps to prevent backups, spills, and overflows.
• By monitoring the pressure in the process, actions can be taken to
prevent (or minimize) an environmental release or personal injury/
exposure.
Cost saving
• The equipment used to create pressure or vacuum in
process industries (e.g., pumps and compressors) uses
considerable energy.
• Because energy costs money, a precise pressure
measurement can save money by preventing the
unnecessary expense of creating more pressure or
vacuum than is required to produce required result.
Process efficiency
Most common example making paper from paper bulb.
The piece of paper on which these words are written
was created from a pulp solution gone through a paper
machine at a specific pressure , If the pressure had
gone above or below the set point (required range),
the result would have been scrap instead of a usable
sheet of paper.
So, The efficiency of a process is directly related to the
quality of the product being produced.
Measurement of other variables
Pressure transmitters are frequently used to measure..
⇨ Temperature measurement
⇨ Level of fluid in a tank
⇨ Flow rate measurement through a pipe
⇨ Density of a substance
⇨ Liquid interface measurement
Types of pressure measuring sensors
• Mechanical type Instruments
⇨ Manometers- Comparing the unknown to
known pressure.
⇨ Metal diaphragm or bellows or capsules
⇨ Bourdon tubes.
• Electro-mechanical type Instruments
• Vacuum sensors.
U-Tube Manometer
Explanation
• Let the density of the fluid whose pressure being measured be ρf
and that of the manometer liquid be ρm.
• Equilibrium of the manometer liquid requires that there be the
same force in the two limbs across the plane AA.
• We can write : P+ ρfgh= Pa + ρmgh
• Finally ,
P-Pa =(ρm- ρf )gh
for manometer liquid most commonly used liquid is mercury(Hg)
and basically used for high pressure measurement
2nd common liquid is water and basically used for low pressure.
Contd..
• When measuring pressures close to the atmospheric
pressure in gases, the fluid density may be quite
negligible in comparison
with the manometer liquid density.
• Rewriting : P – Pa≈ ρm gh
for mercury manometer :
ρm=13600kg/m3
ρf=1kg/m3
Contd..
Advantages :
• Manometers include simple and time proven construction.
• High accuracy.
• Good repeatability.
• Wide range of filling fluids and use as primary standard or as
working device.
Disadvantages :
• Include lack of portability.
• Need of leveling, the hazardous condition existing when
mercury is used as the filling fluid and exposed to the atmosphere
and the reading error due to the meniscus on small diameter tubes.
Well type Manometer
• Sometimes a well type manometer is used and it operates in
the same manner as the U-tube manometer, except that
construction.
• In the well type manometer, one of the legs of the U-tube is
substituted by a large well such that the variation in the level
in the well will be negligible and instead of measuring a
differential height, a single height in the remaining column is
measured.
• The advantage of the well type design is that relatively large
pressure differences may be measured with enough
manometer liquid being available for doing so.
Contd..
Well type inclined manometer
In case the measured pressure difference is small one may use
an inclined well type manometer
Summary
Advantages :
• Very simple
• No calibration required.
Disadvantages :
• slow response – for fluctuating pressures not useful, useful only for
slow varying pressures.
• For the "U" tube manometer two measurements must be taken
simultaneously to get the h value. This may be avoided by using a tube
with a much larger cross-sectional area on one side of the manometer
than the other.
• For very accurate work the temperature and relationship between
temperature and density of the manometric liquid must be known.
Elastic type pressure sensors
Elastic members are also used for measurement of
pressure up to 700 MPa.
⇨ Bourdon tube or pressure spring.
⇨ Bellows elements
⇨ Diaphragms.
Bellows and Diaphragms can be useable up to 3-6
Mpa but bourdon tubes for very high range.
Bourdon tube
• Bourdon tube pressure gages are extensively used for
local indication and signal transmission to remote
location.
• There are three types of bourbon elements
⇨ c-Type
⇨ spiral
⇨ Helical
C-type
• Bourdon gages are purely mechanical devices utilizing the
mechanical deformation of a flattened but bent tube.
• The motion is against a spring torque such that a needle
attached to the shaft indicates directly the pressure
difference.
C- Type working
The Bourdon tube is a metal tube of
elliptic cross section having a bent
shape.
• The inside of the tube is exposed to the
pressure to be measured. The outside of
the Bourdon tube is exposed to a second
pressure, usually the atmospheric.
• The Bourdon tube is held fixed at one
end (the end connected to the pressure
source) and the other end is connected
by linkages to a spring restrained shaft.
• A pointer is mounted on the shaft. The
needle moves over a circular scale that
indicates the pressure.
The position of the needle is determined
by a balance between the Bourdon tube
developed torque acting on the shaft and
the torque due to the shaft mounted
spring that opposes its movement.
Note
• The commercial Bourdon pressure gauges have near elliptical
cross section and tube generally bend into a C- shape or arc
length of about 27 degrees.
• The materials used are commonly Phosphor Bronze, Brass and
Beryllium Copper
Parts of Bourdon tube
Contd..
Mounting position
sensitivity
Spiral type
The spiral bourdon element is used when the free-end movement
of the C-type is not great enough to provide the needed motion.
• Since greater movement of the free end is attained with the
spiral element, it is not necessary, in most cases, for mechanical
amplification, so better accuracy is obtained.
• Spiral tubes are made by winding the tube with its flattened
cross section in a spiral form of several turns.
• As pressure is applied to the spiral, it tends to uncoil, producing
the relatively long movement of the tip end whose motion can be
used for indication or transmission.
Contd..
Helical type
The helical bourdon element is similar to the spiral element,
except it is wound in the form of a helix.
• It increases the tip travel considerably, producing even greater
amplification than the spiral element.
• Usually a central shaft is installed within the helical element,
and the pointer is driven from this shaft is installed within the
helical element, and the pointer is driven from this shaft by
connecting links.
• This system transmits only the circular motion of the tip to the
pointer and hence, is directly proportional to the changes in the
pressure
Contd..
Need for various type
• The types are varied for specific uses and space
accomodations,for better linearity and larger
sensitivity.
• How ?
The displacement of the tip varies inversely as the
wall thickness and depends upon cross-sectional
form of the tube. But importantly length of the
arc.
Therefore displacement of the of the tip may be
increased by increasing the length of the arc of
the tube without changing the wall thickness.
Factors need to consider
• Nonlinearity
• Hysteresis
• Static error
• Elevation error
Non linearity
• Because of the compound stresses developed in the tube, actual
tip travel is nonlinear in nature.
• However for a small travel of this can be considered to be linear and
parallel to the axis of the link.
• The small linear tip movement is matched with a rotational pointer
movement.
• This is known as multiplication, which can be adjusted by adjusting
the length of the lever. A shorter lever gives larger rotation for the
same amount of tip travel.
• The approximately linear motion of the tip when converted to a
circular motion with a link-lever and pinion attachment, a one-to one
correspondence between them may not occur and a distortion
results. This is known as angularity which can be minimized by
adjusting the length of the link
Hysteresis , Static error and Elevation
error
•Hysteresis:
• Like all elastic elements Bourdon tube element also has some
hysteresis in a given pressure cycle. By proper choice of
material and its heat treatment, this may be kept low.
• Static error:
• It generally appears because of the change in elasticity due to
change in temperature. With temperature rising, elasticity
decreases and hence, indication would increase.
• Materials like Ni-span C, which consists of highest amount of Ni.
Lowest amount of carbon is virtually free from this change and
hence is suitable for low static error.
• Elevation error occurs if the tubing connecting the pressure
measuring element and the pressure point is partially filled
Advantages and Disadvantages
• Simple construction
• Very low cost
• Improved design at high pressure for maximum
safety
⇨ Disadvantages :
• They are susceptible to shock and vibration due
to their large overhang.
• They are subjected to hysteresis
Dead Wight tester
working
• A Bourdon pressure gage may be calibrated by the use of a dead
weight tester, a schematic of which is shown in Figure.
• The dead weight tester consists of an arrangement by which a
piston may be allowed to float over a liquid (usually oil) under
internal pressure and a force in the opposite direction imposed
on the piston by weights placed as indicated in the figure.
• The oil pressure is changed by the pumping piston. The pressure
is calculated as the weight placed on the piston divided by the
cross section area of the piston (the piston is to be oriented
with its axis vertical).
• The gage under test experiences the same pressure by being
connected to a side tube communicating with the oil.
limitations
• The fiction between the cylinder and the
priston.
• The uncertainty in the area of the priston
Typical dead weight tester supplied by
WIKA, Australia

More Related Content

What's hot (20)

Pressure measuring instruments
Pressure measuring instrumentsPressure measuring instruments
Pressure measuring instruments
 
Pressure measurement
Pressure measurementPressure measurement
Pressure measurement
 
PRESSURE INSTRUMENTATION
PRESSURE INSTRUMENTATIONPRESSURE INSTRUMENTATION
PRESSURE INSTRUMENTATION
 
Pressure measurement wiki lesker pumping 3_6_09 (2)
Pressure measurement wiki lesker pumping 3_6_09 (2)Pressure measurement wiki lesker pumping 3_6_09 (2)
Pressure measurement wiki lesker pumping 3_6_09 (2)
 
Flow meter
Flow meterFlow meter
Flow meter
 
Level measurement
Level measurementLevel measurement
Level measurement
 
Pressure measuring devices
Pressure measuring devicesPressure measuring devices
Pressure measuring devices
 
Flowmeter - Brief
Flowmeter   - BriefFlowmeter   - Brief
Flowmeter - Brief
 
About Pressure Gauge & Pressure Transmitter ppt
About Pressure Gauge & Pressure Transmitter pptAbout Pressure Gauge & Pressure Transmitter ppt
About Pressure Gauge & Pressure Transmitter ppt
 
Bourdon pressure gauge
Bourdon pressure gaugeBourdon pressure gauge
Bourdon pressure gauge
 
Pressure measurement
Pressure measurementPressure measurement
Pressure measurement
 
Mechanical pressure gauges
Mechanical pressure gaugesMechanical pressure gauges
Mechanical pressure gauges
 
pressure measuring device
pressure measuring devicepressure measuring device
pressure measuring device
 
Pressure measuring Devices
Pressure measuring DevicesPressure measuring Devices
Pressure measuring Devices
 
Manometer
ManometerManometer
Manometer
 
Flow measurement
Flow measurementFlow measurement
Flow measurement
 
various flow meter
various flow metervarious flow meter
various flow meter
 
Pressure measurement - Manometers
Pressure measurement - ManometersPressure measurement - Manometers
Pressure measurement - Manometers
 
Flow measurement
Flow measurementFlow measurement
Flow measurement
 
Level measurement
Level measurementLevel measurement
Level measurement
 

Viewers also liked

Pressure measurement
Pressure measurementPressure measurement
Pressure measurementSrinivasa Rao
 
fluid mechanics- pressure measurement
fluid mechanics- pressure measurementfluid mechanics- pressure measurement
fluid mechanics- pressure measurementAnkitendran Mishra
 
Pressure Measurement
Pressure MeasurementPressure Measurement
Pressure MeasurementMohammad Atif
 
Work Experience @ Kemblefield.(Thomas Heath)
Work Experience @ Kemblefield.(Thomas Heath)Work Experience @ Kemblefield.(Thomas Heath)
Work Experience @ Kemblefield.(Thomas Heath)EIT
 
Modeling of Propellant Tank Pressurization
Modeling of Propellant Tank PressurizationModeling of Propellant Tank Pressurization
Modeling of Propellant Tank PressurizationAmr Darwish
 
GUIDELINES FOR IMPORTING PRODUCT INTO NIGERIA
GUIDELINES FOR IMPORTING PRODUCT INTO NIGERIAGUIDELINES FOR IMPORTING PRODUCT INTO NIGERIA
GUIDELINES FOR IMPORTING PRODUCT INTO NIGERIADivine Greatman
 
TankerCalc for Bunker Surveyors
TankerCalc for Bunker SurveyorsTankerCalc for Bunker Surveyors
TankerCalc for Bunker SurveyorsMd. Moynul Islam
 
V Agrawal A Sarmad Stoc Expo Presentation Updated2
V Agrawal A Sarmad Stoc Expo Presentation Updated2V Agrawal A Sarmad Stoc Expo Presentation Updated2
V Agrawal A Sarmad Stoc Expo Presentation Updated2Vijay Agrawal
 
Compressed hydrogen2011 11_chato
Compressed hydrogen2011 11_chatoCompressed hydrogen2011 11_chato
Compressed hydrogen2011 11_chatoDavid Chato
 
CargoSurveyor: toolbox for marine cargo surveyors
CargoSurveyor: toolbox for marine cargo surveyorsCargoSurveyor: toolbox for marine cargo surveyors
CargoSurveyor: toolbox for marine cargo surveyorsRon Mooring
 
Oil Terminals And Custody Transfer
Oil Terminals And Custody TransferOil Terminals And Custody Transfer
Oil Terminals And Custody Transferhaesah
 
Preparation of the Cargo Plan
Preparation of the Cargo PlanPreparation of the Cargo Plan
Preparation of the Cargo PlanDivine Greatman
 
pengukuran perhitungan volume minyak standard di tangki darat
pengukuran perhitungan volume minyak standard di tangki daratpengukuran perhitungan volume minyak standard di tangki darat
pengukuran perhitungan volume minyak standard di tangki daratHelmi Wijaya
 
3 prismaflex basic setup operation
3   prismaflex basic setup operation3   prismaflex basic setup operation
3 prismaflex basic setup operationSteven Marshall
 
Efflunt treatment plant ppt
Efflunt treatment plant pptEfflunt treatment plant ppt
Efflunt treatment plant pptRajat Thapliyal
 
Root Canal Treatment
Root Canal TreatmentRoot Canal Treatment
Root Canal Treatmentendodontics
 

Viewers also liked (20)

Pressure measurement
Pressure measurementPressure measurement
Pressure measurement
 
fluid mechanics- pressure measurement
fluid mechanics- pressure measurementfluid mechanics- pressure measurement
fluid mechanics- pressure measurement
 
Pressure Measurement
Pressure MeasurementPressure Measurement
Pressure Measurement
 
Work Experience @ Kemblefield.(Thomas Heath)
Work Experience @ Kemblefield.(Thomas Heath)Work Experience @ Kemblefield.(Thomas Heath)
Work Experience @ Kemblefield.(Thomas Heath)
 
Modeling of Propellant Tank Pressurization
Modeling of Propellant Tank PressurizationModeling of Propellant Tank Pressurization
Modeling of Propellant Tank Pressurization
 
GUIDELINES FOR IMPORTING PRODUCT INTO NIGERIA
GUIDELINES FOR IMPORTING PRODUCT INTO NIGERIAGUIDELINES FOR IMPORTING PRODUCT INTO NIGERIA
GUIDELINES FOR IMPORTING PRODUCT INTO NIGERIA
 
Waster water treatment
Waster water treatmentWaster water treatment
Waster water treatment
 
Waste Water Treatment
Waste Water TreatmentWaste Water Treatment
Waste Water Treatment
 
TankerCalc for Bunker Surveyors
TankerCalc for Bunker SurveyorsTankerCalc for Bunker Surveyors
TankerCalc for Bunker Surveyors
 
V Agrawal A Sarmad Stoc Expo Presentation Updated2
V Agrawal A Sarmad Stoc Expo Presentation Updated2V Agrawal A Sarmad Stoc Expo Presentation Updated2
V Agrawal A Sarmad Stoc Expo Presentation Updated2
 
20100022074
2010002207420100022074
20100022074
 
Compressed hydrogen2011 11_chato
Compressed hydrogen2011 11_chatoCompressed hydrogen2011 11_chato
Compressed hydrogen2011 11_chato
 
Duti 254 D
Duti 254 DDuti 254 D
Duti 254 D
 
CargoSurveyor: toolbox for marine cargo surveyors
CargoSurveyor: toolbox for marine cargo surveyorsCargoSurveyor: toolbox for marine cargo surveyors
CargoSurveyor: toolbox for marine cargo surveyors
 
Oil Terminals And Custody Transfer
Oil Terminals And Custody TransferOil Terminals And Custody Transfer
Oil Terminals And Custody Transfer
 
Preparation of the Cargo Plan
Preparation of the Cargo PlanPreparation of the Cargo Plan
Preparation of the Cargo Plan
 
pengukuran perhitungan volume minyak standard di tangki darat
pengukuran perhitungan volume minyak standard di tangki daratpengukuran perhitungan volume minyak standard di tangki darat
pengukuran perhitungan volume minyak standard di tangki darat
 
3 prismaflex basic setup operation
3   prismaflex basic setup operation3   prismaflex basic setup operation
3 prismaflex basic setup operation
 
Efflunt treatment plant ppt
Efflunt treatment plant pptEfflunt treatment plant ppt
Efflunt treatment plant ppt
 
Root Canal Treatment
Root Canal TreatmentRoot Canal Treatment
Root Canal Treatment
 

Similar to Pressure measurement id Mitesh Kuamr

Pressure measurement
Pressure measurementPressure measurement
Pressure measurementBRIJ10PATEL
 
Pressure measuring devices
Pressure measuring devicesPressure measuring devices
Pressure measuring devicesSALONI AGARWAL
 
Module_5_PPT_MHM.pptx
Module_5_PPT_MHM.pptxModule_5_PPT_MHM.pptx
Module_5_PPT_MHM.pptxssuser4c0ac0
 
Pressure Measurement Instruments 1.pptx
Pressure Measurement Instruments 1.pptxPressure Measurement Instruments 1.pptx
Pressure Measurement Instruments 1.pptxHanif61
 
Basic Instrument Presentation ( Flow )
Basic Instrument Presentation ( Flow )Basic Instrument Presentation ( Flow )
Basic Instrument Presentation ( Flow )Aziz u rehman Jamali
 
PRESSURE Measurement
 PRESSURE Measurement  PRESSURE Measurement
PRESSURE Measurement marcoReud
 
Flow measurement in industries
Flow measurement in industriesFlow measurement in industries
Flow measurement in industriesMohsin Mulla
 
Basic Instrument Presentation ( pressure )
Basic Instrument Presentation ( pressure  ) Basic Instrument Presentation ( pressure  )
Basic Instrument Presentation ( pressure ) Aziz u rehman Jamali
 
Basic Instrument Presentation ( Level )
Basic Instrument Presentation ( Level )Basic Instrument Presentation ( Level )
Basic Instrument Presentation ( Level )Aziz u rehman Jamali
 
Pressure Measurement Devices MMM
Pressure Measurement Devices MMM Pressure Measurement Devices MMM
Pressure Measurement Devices MMM NishitSanghvi3
 
Flow Measurnment
Flow MeasurnmentFlow Measurnment
Flow MeasurnmentParth Patel
 
UNIT 1 SCTN_Vacuum Fundamentals_011.pptx
UNIT 1 SCTN_Vacuum Fundamentals_011.pptxUNIT 1 SCTN_Vacuum Fundamentals_011.pptx
UNIT 1 SCTN_Vacuum Fundamentals_011.pptxAwnishTripathi4
 
Measurement of flowing Fluid.pdf
Measurement of flowing Fluid.pdfMeasurement of flowing Fluid.pdf
Measurement of flowing Fluid.pdfDHRUVGHAG1
 
Ch6_Flow Measurements.pdf
Ch6_Flow Measurements.pdfCh6_Flow Measurements.pdf
Ch6_Flow Measurements.pdfVamshi962726
 
Ch. no. 4 flow measurement
Ch. no. 4 flow measurementCh. no. 4 flow measurement
Ch. no. 4 flow measurementAmol Kokare
 

Similar to Pressure measurement id Mitesh Kuamr (20)

Pressure measurement
Pressure measurementPressure measurement
Pressure measurement
 
Presentation10-9.ppt
Presentation10-9.pptPresentation10-9.ppt
Presentation10-9.ppt
 
Pressure measuring devices
Pressure measuring devicesPressure measuring devices
Pressure measuring devices
 
5661874.ppt
5661874.ppt5661874.ppt
5661874.ppt
 
Module_5_PPT_MHM.pptx
Module_5_PPT_MHM.pptxModule_5_PPT_MHM.pptx
Module_5_PPT_MHM.pptx
 
Pressure Measurement Instruments 1.pptx
Pressure Measurement Instruments 1.pptxPressure Measurement Instruments 1.pptx
Pressure Measurement Instruments 1.pptx
 
Basic Instrument Presentation ( Flow )
Basic Instrument Presentation ( Flow )Basic Instrument Presentation ( Flow )
Basic Instrument Presentation ( Flow )
 
PRESSURE Measurement
 PRESSURE Measurement  PRESSURE Measurement
PRESSURE Measurement
 
Flow measurement in industries
Flow measurement in industriesFlow measurement in industries
Flow measurement in industries
 
Basic Instrument Presentation ( pressure )
Basic Instrument Presentation ( pressure  ) Basic Instrument Presentation ( pressure  )
Basic Instrument Presentation ( pressure )
 
Basic Instrument Presentation ( Level )
Basic Instrument Presentation ( Level )Basic Instrument Presentation ( Level )
Basic Instrument Presentation ( Level )
 
Pressure Measurement Devices MMM
Pressure Measurement Devices MMM Pressure Measurement Devices MMM
Pressure Measurement Devices MMM
 
I&C Technical Note
I&C Technical NoteI&C Technical Note
I&C Technical Note
 
Flow sensors
Flow sensorsFlow sensors
Flow sensors
 
Flow Measurnment
Flow MeasurnmentFlow Measurnment
Flow Measurnment
 
UNIT 1 SCTN_Vacuum Fundamentals_011.pptx
UNIT 1 SCTN_Vacuum Fundamentals_011.pptxUNIT 1 SCTN_Vacuum Fundamentals_011.pptx
UNIT 1 SCTN_Vacuum Fundamentals_011.pptx
 
Measurement of flowing Fluid.pdf
Measurement of flowing Fluid.pdfMeasurement of flowing Fluid.pdf
Measurement of flowing Fluid.pdf
 
Ch6_Flow Measurements.pdf
Ch6_Flow Measurements.pdfCh6_Flow Measurements.pdf
Ch6_Flow Measurements.pdf
 
Ch. no. 4 flow measurement
Ch. no. 4 flow measurementCh. no. 4 flow measurement
Ch. no. 4 flow measurement
 
Manometers.pptx
Manometers.pptxManometers.pptx
Manometers.pptx
 

More from Mitesh Kumar

Embeded system by Mitesh Kumar
Embeded system by Mitesh KumarEmbeded system by Mitesh Kumar
Embeded system by Mitesh KumarMitesh Kumar
 
Fiber optics measurement Technique by mitesh kumar
Fiber optics measurement Technique by mitesh kumarFiber optics measurement Technique by mitesh kumar
Fiber optics measurement Technique by mitesh kumarMitesh Kumar
 
Microcontroller 8051 By Mitesh kumar
Microcontroller 8051 By Mitesh kumarMicrocontroller 8051 By Mitesh kumar
Microcontroller 8051 By Mitesh kumarMitesh Kumar
 
Temperature measurement By Mitesh Kumar
Temperature  measurement By Mitesh KumarTemperature  measurement By Mitesh Kumar
Temperature measurement By Mitesh KumarMitesh Kumar
 
Synchronous machine by Mitesh Kumar
Synchronous machine by Mitesh KumarSynchronous machine by Mitesh Kumar
Synchronous machine by Mitesh KumarMitesh Kumar
 
Three phase induction motor By Mitesh Kumar
Three phase induction motor By Mitesh KumarThree phase induction motor By Mitesh Kumar
Three phase induction motor By Mitesh KumarMitesh Kumar
 
Transmitter By MItesh Kumar
Transmitter By MItesh KumarTransmitter By MItesh Kumar
Transmitter By MItesh KumarMitesh Kumar
 
Temperature measurement By Mitesh Kumar
Temperature  measurement By Mitesh KumarTemperature  measurement By Mitesh Kumar
Temperature measurement By Mitesh KumarMitesh Kumar
 
Resistance Temperature Detector By Mitesh Kumar
Resistance Temperature Detector By Mitesh KumarResistance Temperature Detector By Mitesh Kumar
Resistance Temperature Detector By Mitesh KumarMitesh Kumar
 
Synchronous machine Mitesh Kumar
Synchronous machine Mitesh KumarSynchronous machine Mitesh Kumar
Synchronous machine Mitesh KumarMitesh Kumar
 
Piezoelectric pressure sensor Mitesh Kumar
Piezoelectric pressure sensor Mitesh KumarPiezoelectric pressure sensor Mitesh Kumar
Piezoelectric pressure sensor Mitesh KumarMitesh Kumar
 
Optical measurent Mitesh kumar
Optical measurent Mitesh kumarOptical measurent Mitesh kumar
Optical measurent Mitesh kumarMitesh Kumar
 
Net neutrality by Mitesh Kumar
Net neutrality by Mitesh KumarNet neutrality by Mitesh Kumar
Net neutrality by Mitesh KumarMitesh Kumar
 
Dc to Ac inverter By Mitesh Kumar
Dc to Ac inverter By Mitesh KumarDc to Ac inverter By Mitesh Kumar
Dc to Ac inverter By Mitesh KumarMitesh Kumar
 
Pid controller by Mitesh Kumar
Pid controller by Mitesh KumarPid controller by Mitesh Kumar
Pid controller by Mitesh KumarMitesh Kumar
 
Network problem cpm and pert BY MITESH KUMAR
Network problem cpm and pert BY MITESH KUMARNetwork problem cpm and pert BY MITESH KUMAR
Network problem cpm and pert BY MITESH KUMARMitesh Kumar
 
Water pollution treatment BY Mitesh Kumar
Water pollution treatment BY Mitesh KumarWater pollution treatment BY Mitesh Kumar
Water pollution treatment BY Mitesh KumarMitesh Kumar
 
Biomass ppt By Mitesh Kumar
Biomass ppt By Mitesh KumarBiomass ppt By Mitesh Kumar
Biomass ppt By Mitesh KumarMitesh Kumar
 
Humanoid robot by mitesh kumar
Humanoid robot by mitesh kumarHumanoid robot by mitesh kumar
Humanoid robot by mitesh kumarMitesh Kumar
 
Humanoid robot by Mitesh kumar
Humanoid robot by Mitesh kumar Humanoid robot by Mitesh kumar
Humanoid robot by Mitesh kumar Mitesh Kumar
 

More from Mitesh Kumar (20)

Embeded system by Mitesh Kumar
Embeded system by Mitesh KumarEmbeded system by Mitesh Kumar
Embeded system by Mitesh Kumar
 
Fiber optics measurement Technique by mitesh kumar
Fiber optics measurement Technique by mitesh kumarFiber optics measurement Technique by mitesh kumar
Fiber optics measurement Technique by mitesh kumar
 
Microcontroller 8051 By Mitesh kumar
Microcontroller 8051 By Mitesh kumarMicrocontroller 8051 By Mitesh kumar
Microcontroller 8051 By Mitesh kumar
 
Temperature measurement By Mitesh Kumar
Temperature  measurement By Mitesh KumarTemperature  measurement By Mitesh Kumar
Temperature measurement By Mitesh Kumar
 
Synchronous machine by Mitesh Kumar
Synchronous machine by Mitesh KumarSynchronous machine by Mitesh Kumar
Synchronous machine by Mitesh Kumar
 
Three phase induction motor By Mitesh Kumar
Three phase induction motor By Mitesh KumarThree phase induction motor By Mitesh Kumar
Three phase induction motor By Mitesh Kumar
 
Transmitter By MItesh Kumar
Transmitter By MItesh KumarTransmitter By MItesh Kumar
Transmitter By MItesh Kumar
 
Temperature measurement By Mitesh Kumar
Temperature  measurement By Mitesh KumarTemperature  measurement By Mitesh Kumar
Temperature measurement By Mitesh Kumar
 
Resistance Temperature Detector By Mitesh Kumar
Resistance Temperature Detector By Mitesh KumarResistance Temperature Detector By Mitesh Kumar
Resistance Temperature Detector By Mitesh Kumar
 
Synchronous machine Mitesh Kumar
Synchronous machine Mitesh KumarSynchronous machine Mitesh Kumar
Synchronous machine Mitesh Kumar
 
Piezoelectric pressure sensor Mitesh Kumar
Piezoelectric pressure sensor Mitesh KumarPiezoelectric pressure sensor Mitesh Kumar
Piezoelectric pressure sensor Mitesh Kumar
 
Optical measurent Mitesh kumar
Optical measurent Mitesh kumarOptical measurent Mitesh kumar
Optical measurent Mitesh kumar
 
Net neutrality by Mitesh Kumar
Net neutrality by Mitesh KumarNet neutrality by Mitesh Kumar
Net neutrality by Mitesh Kumar
 
Dc to Ac inverter By Mitesh Kumar
Dc to Ac inverter By Mitesh KumarDc to Ac inverter By Mitesh Kumar
Dc to Ac inverter By Mitesh Kumar
 
Pid controller by Mitesh Kumar
Pid controller by Mitesh KumarPid controller by Mitesh Kumar
Pid controller by Mitesh Kumar
 
Network problem cpm and pert BY MITESH KUMAR
Network problem cpm and pert BY MITESH KUMARNetwork problem cpm and pert BY MITESH KUMAR
Network problem cpm and pert BY MITESH KUMAR
 
Water pollution treatment BY Mitesh Kumar
Water pollution treatment BY Mitesh KumarWater pollution treatment BY Mitesh Kumar
Water pollution treatment BY Mitesh Kumar
 
Biomass ppt By Mitesh Kumar
Biomass ppt By Mitesh KumarBiomass ppt By Mitesh Kumar
Biomass ppt By Mitesh Kumar
 
Humanoid robot by mitesh kumar
Humanoid robot by mitesh kumarHumanoid robot by mitesh kumar
Humanoid robot by mitesh kumar
 
Humanoid robot by Mitesh kumar
Humanoid robot by Mitesh kumar Humanoid robot by Mitesh kumar
Humanoid robot by Mitesh kumar
 

Recently uploaded

signals in triangulation .. ...Surveying
signals in triangulation .. ...Surveyingsignals in triangulation .. ...Surveying
signals in triangulation .. ...Surveyingsapna80328
 
Paper Tube : Shigeru Ban projects and Case Study of Cardboard Cathedral .pdf
Paper Tube : Shigeru Ban projects and Case Study of Cardboard Cathedral .pdfPaper Tube : Shigeru Ban projects and Case Study of Cardboard Cathedral .pdf
Paper Tube : Shigeru Ban projects and Case Study of Cardboard Cathedral .pdfNainaShrivastava14
 
Gravity concentration_MI20612MI_________
Gravity concentration_MI20612MI_________Gravity concentration_MI20612MI_________
Gravity concentration_MI20612MI_________Romil Mishra
 
Katarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School CourseKatarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School Coursebim.edu.pl
 
Python Programming for basic beginners.pptx
Python Programming for basic beginners.pptxPython Programming for basic beginners.pptx
Python Programming for basic beginners.pptxmohitesoham12
 
DEVICE DRIVERS AND INTERRUPTS SERVICE MECHANISM.pdf
DEVICE DRIVERS AND INTERRUPTS  SERVICE MECHANISM.pdfDEVICE DRIVERS AND INTERRUPTS  SERVICE MECHANISM.pdf
DEVICE DRIVERS AND INTERRUPTS SERVICE MECHANISM.pdfAkritiPradhan2
 
Earthing details of Electrical Substation
Earthing details of Electrical SubstationEarthing details of Electrical Substation
Earthing details of Electrical Substationstephanwindworld
 
CS 3251 Programming in c all unit notes pdf
CS 3251 Programming in c all unit notes pdfCS 3251 Programming in c all unit notes pdf
CS 3251 Programming in c all unit notes pdfBalamuruganV28
 
"Exploring the Essential Functions and Design Considerations of Spillways in ...
"Exploring the Essential Functions and Design Considerations of Spillways in ..."Exploring the Essential Functions and Design Considerations of Spillways in ...
"Exploring the Essential Functions and Design Considerations of Spillways in ...Erbil Polytechnic University
 
11. Properties of Liquid Fuels in Energy Engineering.pdf
11. Properties of Liquid Fuels in Energy Engineering.pdf11. Properties of Liquid Fuels in Energy Engineering.pdf
11. Properties of Liquid Fuels in Energy Engineering.pdfHafizMudaserAhmad
 
Novel 3D-Printed Soft Linear and Bending Actuators
Novel 3D-Printed Soft Linear and Bending ActuatorsNovel 3D-Printed Soft Linear and Bending Actuators
Novel 3D-Printed Soft Linear and Bending ActuatorsResearcher Researcher
 
Industrial Applications of Centrifugal Compressors
Industrial Applications of Centrifugal CompressorsIndustrial Applications of Centrifugal Compressors
Industrial Applications of Centrifugal CompressorsAlirezaBagherian3
 
SOFTWARE ESTIMATION COCOMO AND FP CALCULATION
SOFTWARE ESTIMATION COCOMO AND FP CALCULATIONSOFTWARE ESTIMATION COCOMO AND FP CALCULATION
SOFTWARE ESTIMATION COCOMO AND FP CALCULATIONSneha Padhiar
 
CME 397 - SURFACE ENGINEERING - UNIT 1 FULL NOTES
CME 397 - SURFACE ENGINEERING - UNIT 1 FULL NOTESCME 397 - SURFACE ENGINEERING - UNIT 1 FULL NOTES
CME 397 - SURFACE ENGINEERING - UNIT 1 FULL NOTESkarthi keyan
 
US Department of Education FAFSA Week of Action
US Department of Education FAFSA Week of ActionUS Department of Education FAFSA Week of Action
US Department of Education FAFSA Week of ActionMebane Rash
 
TechTAC® CFD Report Summary: A Comparison of Two Types of Tubing Anchor Catchers
TechTAC® CFD Report Summary: A Comparison of Two Types of Tubing Anchor CatchersTechTAC® CFD Report Summary: A Comparison of Two Types of Tubing Anchor Catchers
TechTAC® CFD Report Summary: A Comparison of Two Types of Tubing Anchor Catcherssdickerson1
 
THE SENDAI FRAMEWORK FOR DISASTER RISK REDUCTION
THE SENDAI FRAMEWORK FOR DISASTER RISK REDUCTIONTHE SENDAI FRAMEWORK FOR DISASTER RISK REDUCTION
THE SENDAI FRAMEWORK FOR DISASTER RISK REDUCTIONjhunlian
 
Main Memory Management in Operating System
Main Memory Management in Operating SystemMain Memory Management in Operating System
Main Memory Management in Operating SystemRashmi Bhat
 
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.elesangwon
 
Energy Awareness training ppt for manufacturing process.pptx
Energy Awareness training ppt for manufacturing process.pptxEnergy Awareness training ppt for manufacturing process.pptx
Energy Awareness training ppt for manufacturing process.pptxsiddharthjain2303
 

Recently uploaded (20)

signals in triangulation .. ...Surveying
signals in triangulation .. ...Surveyingsignals in triangulation .. ...Surveying
signals in triangulation .. ...Surveying
 
Paper Tube : Shigeru Ban projects and Case Study of Cardboard Cathedral .pdf
Paper Tube : Shigeru Ban projects and Case Study of Cardboard Cathedral .pdfPaper Tube : Shigeru Ban projects and Case Study of Cardboard Cathedral .pdf
Paper Tube : Shigeru Ban projects and Case Study of Cardboard Cathedral .pdf
 
Gravity concentration_MI20612MI_________
Gravity concentration_MI20612MI_________Gravity concentration_MI20612MI_________
Gravity concentration_MI20612MI_________
 
Katarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School CourseKatarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School Course
 
Python Programming for basic beginners.pptx
Python Programming for basic beginners.pptxPython Programming for basic beginners.pptx
Python Programming for basic beginners.pptx
 
DEVICE DRIVERS AND INTERRUPTS SERVICE MECHANISM.pdf
DEVICE DRIVERS AND INTERRUPTS  SERVICE MECHANISM.pdfDEVICE DRIVERS AND INTERRUPTS  SERVICE MECHANISM.pdf
DEVICE DRIVERS AND INTERRUPTS SERVICE MECHANISM.pdf
 
Earthing details of Electrical Substation
Earthing details of Electrical SubstationEarthing details of Electrical Substation
Earthing details of Electrical Substation
 
CS 3251 Programming in c all unit notes pdf
CS 3251 Programming in c all unit notes pdfCS 3251 Programming in c all unit notes pdf
CS 3251 Programming in c all unit notes pdf
 
"Exploring the Essential Functions and Design Considerations of Spillways in ...
"Exploring the Essential Functions and Design Considerations of Spillways in ..."Exploring the Essential Functions and Design Considerations of Spillways in ...
"Exploring the Essential Functions and Design Considerations of Spillways in ...
 
11. Properties of Liquid Fuels in Energy Engineering.pdf
11. Properties of Liquid Fuels in Energy Engineering.pdf11. Properties of Liquid Fuels in Energy Engineering.pdf
11. Properties of Liquid Fuels in Energy Engineering.pdf
 
Novel 3D-Printed Soft Linear and Bending Actuators
Novel 3D-Printed Soft Linear and Bending ActuatorsNovel 3D-Printed Soft Linear and Bending Actuators
Novel 3D-Printed Soft Linear and Bending Actuators
 
Industrial Applications of Centrifugal Compressors
Industrial Applications of Centrifugal CompressorsIndustrial Applications of Centrifugal Compressors
Industrial Applications of Centrifugal Compressors
 
SOFTWARE ESTIMATION COCOMO AND FP CALCULATION
SOFTWARE ESTIMATION COCOMO AND FP CALCULATIONSOFTWARE ESTIMATION COCOMO AND FP CALCULATION
SOFTWARE ESTIMATION COCOMO AND FP CALCULATION
 
CME 397 - SURFACE ENGINEERING - UNIT 1 FULL NOTES
CME 397 - SURFACE ENGINEERING - UNIT 1 FULL NOTESCME 397 - SURFACE ENGINEERING - UNIT 1 FULL NOTES
CME 397 - SURFACE ENGINEERING - UNIT 1 FULL NOTES
 
US Department of Education FAFSA Week of Action
US Department of Education FAFSA Week of ActionUS Department of Education FAFSA Week of Action
US Department of Education FAFSA Week of Action
 
TechTAC® CFD Report Summary: A Comparison of Two Types of Tubing Anchor Catchers
TechTAC® CFD Report Summary: A Comparison of Two Types of Tubing Anchor CatchersTechTAC® CFD Report Summary: A Comparison of Two Types of Tubing Anchor Catchers
TechTAC® CFD Report Summary: A Comparison of Two Types of Tubing Anchor Catchers
 
THE SENDAI FRAMEWORK FOR DISASTER RISK REDUCTION
THE SENDAI FRAMEWORK FOR DISASTER RISK REDUCTIONTHE SENDAI FRAMEWORK FOR DISASTER RISK REDUCTION
THE SENDAI FRAMEWORK FOR DISASTER RISK REDUCTION
 
Main Memory Management in Operating System
Main Memory Management in Operating SystemMain Memory Management in Operating System
Main Memory Management in Operating System
 
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
 
Energy Awareness training ppt for manufacturing process.pptx
Energy Awareness training ppt for manufacturing process.pptxEnergy Awareness training ppt for manufacturing process.pptx
Energy Awareness training ppt for manufacturing process.pptx
 

Pressure measurement id Mitesh Kuamr

  • 1. Pressure measurementMITESH KUMAR Rall no-10300513026 Applied Electronics & Instrumentation Engg. Haldia Institute Of Technology
  • 2. Density D=M⁄V So for greater density mass will more in the substance in unit volume. And greater density will give more hydrostatic(head) pressure than lower density. Density always define in given temperature because density of a liquid decreases as temperature increases. This temperature is here reference temp.
  • 3. Specific gravity • Some time density can define in terms of Specific gravity. • Specific gravity is the ratio of the density of a particular liquid to the density of water at a reference temperature. problem: Water has a density of 1,000 kg/m3 at 50 °F. The density of gasoline is 660 kg/m3 at 50 °F. calculate Specific gravity of gasoline?
  • 4. • Ullage Pressure is pressure that is exerted on the surface of a liquid. • In an open tank, atmospheric pressure (the pressure exerted by the Earth’s atmosphere) is the pressure on the surface. • A gauge pressure measurement is sufficient for level measurement. • In a closed tank, it is common practice to fill the vapor space with buffer gas. This is done in order to protect the products inside the tank or to prevent them from evaporating into atmosphere. • This buffer gas will exert a pressure on the column of liquid that must be subtracted from the measurement of the height of the liquid column otherwise error will occur. • Differential pressure measurement, where the low side reference leg is connected to the vapor space will allow the head pressure to be subtracted out. Ullage Pressure
  • 5. Factors for gas • Factors for gas’s exert pressure ⇨ Gas container volume ⇨ Gas temperature. There is ideal gas law relating it’s pressure temperature and volume. PV= nRT
  • 6. Relations between gas pressure and volume Boyel’s law : It is stated that that the pressure and volume of a gas have an inverse relationship, when temperature is held constant. P1V1= P2V2 A fixed amount of gas is transferred to a larger container, the pressure will decrease in proportion to the increase in container volume. So we can conclude that gas can be compressed, the pressure of a gas increases proportionately as the volume of the container in which it is held decreases.
  • 7. Need of pressure measurement • There are four common need ⇨ Safety ⇨ Process efficiency ⇨ Cost savings ⇨ Measurement of other process variables
  • 8. Safety • Pipes, tanks, valves, and other equipment used with pressurized fluids in process industries are designed to withstand the stress of a specific range of pressures. • Accurate pressure measurement and precise control help prevent pipes and vessels from bursting. • In addition, pressure measurement and control help minimize equipment damage, reduce the risk of personal injury, and prevent leaks of potentially harmful process materials into the environment. • Pressure measurement used to control the level and flow of process materials helps to prevent backups, spills, and overflows. • By monitoring the pressure in the process, actions can be taken to prevent (or minimize) an environmental release or personal injury/ exposure.
  • 9. Cost saving • The equipment used to create pressure or vacuum in process industries (e.g., pumps and compressors) uses considerable energy. • Because energy costs money, a precise pressure measurement can save money by preventing the unnecessary expense of creating more pressure or vacuum than is required to produce required result.
  • 10. Process efficiency Most common example making paper from paper bulb. The piece of paper on which these words are written was created from a pulp solution gone through a paper machine at a specific pressure , If the pressure had gone above or below the set point (required range), the result would have been scrap instead of a usable sheet of paper. So, The efficiency of a process is directly related to the quality of the product being produced.
  • 11. Measurement of other variables Pressure transmitters are frequently used to measure.. ⇨ Temperature measurement ⇨ Level of fluid in a tank ⇨ Flow rate measurement through a pipe ⇨ Density of a substance ⇨ Liquid interface measurement
  • 12. Types of pressure measuring sensors • Mechanical type Instruments ⇨ Manometers- Comparing the unknown to known pressure. ⇨ Metal diaphragm or bellows or capsules ⇨ Bourdon tubes. • Electro-mechanical type Instruments • Vacuum sensors.
  • 14. Explanation • Let the density of the fluid whose pressure being measured be ρf and that of the manometer liquid be ρm. • Equilibrium of the manometer liquid requires that there be the same force in the two limbs across the plane AA. • We can write : P+ ρfgh= Pa + ρmgh • Finally , P-Pa =(ρm- ρf )gh for manometer liquid most commonly used liquid is mercury(Hg) and basically used for high pressure measurement 2nd common liquid is water and basically used for low pressure.
  • 15. Contd.. • When measuring pressures close to the atmospheric pressure in gases, the fluid density may be quite negligible in comparison with the manometer liquid density. • Rewriting : P – Pa≈ ρm gh for mercury manometer : ρm=13600kg/m3 ρf=1kg/m3
  • 16. Contd.. Advantages : • Manometers include simple and time proven construction. • High accuracy. • Good repeatability. • Wide range of filling fluids and use as primary standard or as working device. Disadvantages : • Include lack of portability. • Need of leveling, the hazardous condition existing when mercury is used as the filling fluid and exposed to the atmosphere and the reading error due to the meniscus on small diameter tubes.
  • 17. Well type Manometer • Sometimes a well type manometer is used and it operates in the same manner as the U-tube manometer, except that construction. • In the well type manometer, one of the legs of the U-tube is substituted by a large well such that the variation in the level in the well will be negligible and instead of measuring a differential height, a single height in the remaining column is measured. • The advantage of the well type design is that relatively large pressure differences may be measured with enough manometer liquid being available for doing so.
  • 19. Well type inclined manometer In case the measured pressure difference is small one may use an inclined well type manometer
  • 20. Summary Advantages : • Very simple • No calibration required. Disadvantages : • slow response – for fluctuating pressures not useful, useful only for slow varying pressures. • For the "U" tube manometer two measurements must be taken simultaneously to get the h value. This may be avoided by using a tube with a much larger cross-sectional area on one side of the manometer than the other. • For very accurate work the temperature and relationship between temperature and density of the manometric liquid must be known.
  • 21. Elastic type pressure sensors Elastic members are also used for measurement of pressure up to 700 MPa. ⇨ Bourdon tube or pressure spring. ⇨ Bellows elements ⇨ Diaphragms. Bellows and Diaphragms can be useable up to 3-6 Mpa but bourdon tubes for very high range.
  • 22. Bourdon tube • Bourdon tube pressure gages are extensively used for local indication and signal transmission to remote location. • There are three types of bourbon elements ⇨ c-Type ⇨ spiral ⇨ Helical
  • 23. C-type • Bourdon gages are purely mechanical devices utilizing the mechanical deformation of a flattened but bent tube. • The motion is against a spring torque such that a needle attached to the shaft indicates directly the pressure difference.
  • 24. C- Type working The Bourdon tube is a metal tube of elliptic cross section having a bent shape. • The inside of the tube is exposed to the pressure to be measured. The outside of the Bourdon tube is exposed to a second pressure, usually the atmospheric. • The Bourdon tube is held fixed at one end (the end connected to the pressure source) and the other end is connected by linkages to a spring restrained shaft. • A pointer is mounted on the shaft. The needle moves over a circular scale that indicates the pressure. The position of the needle is determined by a balance between the Bourdon tube developed torque acting on the shaft and the torque due to the shaft mounted spring that opposes its movement.
  • 25. Note • The commercial Bourdon pressure gauges have near elliptical cross section and tube generally bend into a C- shape or arc length of about 27 degrees. • The materials used are commonly Phosphor Bronze, Brass and Beryllium Copper
  • 30. Spiral type The spiral bourdon element is used when the free-end movement of the C-type is not great enough to provide the needed motion. • Since greater movement of the free end is attained with the spiral element, it is not necessary, in most cases, for mechanical amplification, so better accuracy is obtained. • Spiral tubes are made by winding the tube with its flattened cross section in a spiral form of several turns. • As pressure is applied to the spiral, it tends to uncoil, producing the relatively long movement of the tip end whose motion can be used for indication or transmission.
  • 32. Helical type The helical bourdon element is similar to the spiral element, except it is wound in the form of a helix. • It increases the tip travel considerably, producing even greater amplification than the spiral element. • Usually a central shaft is installed within the helical element, and the pointer is driven from this shaft is installed within the helical element, and the pointer is driven from this shaft by connecting links. • This system transmits only the circular motion of the tip to the pointer and hence, is directly proportional to the changes in the pressure
  • 34. Need for various type • The types are varied for specific uses and space accomodations,for better linearity and larger sensitivity. • How ? The displacement of the tip varies inversely as the wall thickness and depends upon cross-sectional form of the tube. But importantly length of the arc. Therefore displacement of the of the tip may be increased by increasing the length of the arc of the tube without changing the wall thickness.
  • 35. Factors need to consider • Nonlinearity • Hysteresis • Static error • Elevation error
  • 36. Non linearity • Because of the compound stresses developed in the tube, actual tip travel is nonlinear in nature. • However for a small travel of this can be considered to be linear and parallel to the axis of the link. • The small linear tip movement is matched with a rotational pointer movement. • This is known as multiplication, which can be adjusted by adjusting the length of the lever. A shorter lever gives larger rotation for the same amount of tip travel. • The approximately linear motion of the tip when converted to a circular motion with a link-lever and pinion attachment, a one-to one correspondence between them may not occur and a distortion results. This is known as angularity which can be minimized by adjusting the length of the link
  • 37. Hysteresis , Static error and Elevation error •Hysteresis: • Like all elastic elements Bourdon tube element also has some hysteresis in a given pressure cycle. By proper choice of material and its heat treatment, this may be kept low. • Static error: • It generally appears because of the change in elasticity due to change in temperature. With temperature rising, elasticity decreases and hence, indication would increase. • Materials like Ni-span C, which consists of highest amount of Ni. Lowest amount of carbon is virtually free from this change and hence is suitable for low static error. • Elevation error occurs if the tubing connecting the pressure measuring element and the pressure point is partially filled
  • 38. Advantages and Disadvantages • Simple construction • Very low cost • Improved design at high pressure for maximum safety ⇨ Disadvantages : • They are susceptible to shock and vibration due to their large overhang. • They are subjected to hysteresis
  • 40. working • A Bourdon pressure gage may be calibrated by the use of a dead weight tester, a schematic of which is shown in Figure. • The dead weight tester consists of an arrangement by which a piston may be allowed to float over a liquid (usually oil) under internal pressure and a force in the opposite direction imposed on the piston by weights placed as indicated in the figure. • The oil pressure is changed by the pumping piston. The pressure is calculated as the weight placed on the piston divided by the cross section area of the piston (the piston is to be oriented with its axis vertical). • The gage under test experiences the same pressure by being connected to a side tube communicating with the oil.
  • 41. limitations • The fiction between the cylinder and the priston. • The uncertainty in the area of the priston
  • 42. Typical dead weight tester supplied by WIKA, Australia