This document discusses various methods and instruments used to measure pressure. It describes different types of pressure measurements including absolute pressure, gauge pressure, and differential pressure. It then explains several common pressure measurement instruments such as manometers, piston gauges, bourdon gauges, and diaphragm gauges. The document also discusses thermal conductivity gauges like Pirani gauges, as well as ionization gauges and how they work. Finally, it provides an overview of various vacuum pump technologies including rotary vane pumps, scroll pumps, diffusion pumps, turbomolecular pumps, and cryopumps.
You'll find a wonderful explanation of the following topics:-
Sensing Elements,Bellows ,Bourdon tube,Impact of Operating Environment ,Diaphragm,Differen,capacitance,tial Pressure Transmitters,strain gauge
You'll find a wonderful explanation of the following topics:-
Sensing Elements,Bellows ,Bourdon tube,Impact of Operating Environment ,Diaphragm,Differen,capacitance,tial Pressure Transmitters,strain gauge
Level Measurement
one can go through this ppt to learn about level measurement
you will be learning following points through it.
1.meaning of level measurement
2.Need of level measurement
3.selection of level measurement devices.
4.types of level measurements
5.types of direct measurements
6.types of indirect level measurements.
7. capacitance level measurement
8. materials used and their working ranges
9. advantages , Disadvantages of it.
10. Practical applications with videos.
11. proper explanation about working of all methods,easy to understand.
one will thoroughly learn the principle of level measurement after going through this ppt , it will help u in clearing some concepts about measurement principle.
Liquid Level Measurement By Indirect MethodJaydeep Vakil
This ppt contains Differential Method for measuring of liquid level of storage tanks and vessels. Differential method is one of the indirect method for liquid level measurement..
Gives a brief introduction about temperature measurement and its unit. it also enumerates the different techniques employed in temperature measurement.
various types of flow meter
1. rotameter
2. venturimeter
3. electromagnetic flow meter
4. positive displacement flow meter
with their working advantage and disadvantages
Generalized Measurement System is a measuring system exists to provide information about the physical value of some variable being measured. In this presentation, generalized measurement system, its elements, classification of instruments, classification of measurement methods, difference between mechanical and electrical measurement systems, input output characteristics are described.
Level Measurement
one can go through this ppt to learn about level measurement
you will be learning following points through it.
1.meaning of level measurement
2.Need of level measurement
3.selection of level measurement devices.
4.types of level measurements
5.types of direct measurements
6.types of indirect level measurements.
7. capacitance level measurement
8. materials used and their working ranges
9. advantages , Disadvantages of it.
10. Practical applications with videos.
11. proper explanation about working of all methods,easy to understand.
one will thoroughly learn the principle of level measurement after going through this ppt , it will help u in clearing some concepts about measurement principle.
Liquid Level Measurement By Indirect MethodJaydeep Vakil
This ppt contains Differential Method for measuring of liquid level of storage tanks and vessels. Differential method is one of the indirect method for liquid level measurement..
Gives a brief introduction about temperature measurement and its unit. it also enumerates the different techniques employed in temperature measurement.
various types of flow meter
1. rotameter
2. venturimeter
3. electromagnetic flow meter
4. positive displacement flow meter
with their working advantage and disadvantages
Generalized Measurement System is a measuring system exists to provide information about the physical value of some variable being measured. In this presentation, generalized measurement system, its elements, classification of instruments, classification of measurement methods, difference between mechanical and electrical measurement systems, input output characteristics are described.
Conventional and non-conventional energy sources, Hydro-electric, Thermal, Nuclear, Wind, Solar(with block diagram)
Boiler- Water tube and Fire tube, Internal Combustion Engines–Two stroke and four stroke (spark ignition and compression ignition), Turbines– Impulse & Reaction
This presentation gives the information about Force, Pressure and Torque measurements of the subject: Mechanical measurement and Metrology (10ME32/42) of VTU Syllabus covering unit-6.
Following Devices are described. All the best !!!
Bourdon Gauge Tube
Diaphragms
Bellow Gauge
Piezoelectric Pressure Sensors
INDUCTIVE TRANSDUCERS
Pirani Gauge (One Wire)
Ionization gauge
The presentation discusses a general introduction to fluids and solids; fluid properties; Hydrostatics of fluids; pressure measurement and measurement systems; application of hydrostatics principle; Some concepts on mement of area, second moment of Area, Area centroid, object center of gravity; Hydr...
ALL EYES ON RAFAH BUT WHY Explain more.pdf46adnanshahzad
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How to Obtain Permanent Residency in the NetherlandsBridgeWest.eu
You can rely on our assistance if you are ready to apply for permanent residency. Find out more at: https://immigration-netherlands.com/obtain-a-permanent-residence-permit-in-the-netherlands/.
In 2020, the Ministry of Home Affairs established a committee led by Prof. (Dr.) Ranbir Singh, former Vice Chancellor of National Law University (NLU), Delhi. This committee was tasked with reviewing the three codes of criminal law. The primary objective of the committee was to propose comprehensive reforms to the country’s criminal laws in a manner that is both principled and effective.
The committee’s focus was on ensuring the safety and security of individuals, communities, and the nation as a whole. Throughout its deliberations, the committee aimed to uphold constitutional values such as justice, dignity, and the intrinsic value of each individual. Their goal was to recommend amendments to the criminal laws that align with these values and priorities.
Subsequently, in February, the committee successfully submitted its recommendations regarding amendments to the criminal law. These recommendations are intended to serve as a foundation for enhancing the current legal framework, promoting safety and security, and upholding the constitutional principles of justice, dignity, and the inherent worth of every individual.
Synopsis On Annual General Meeting/Extra Ordinary General Meeting With Ordinary And Special Businesses And Ordinary And Special Resolutions with Companies (Postal Ballot) Regulations, 2018
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Military Commissions details LtCol Thomas Jasper as Detailed Defense Counsel
Pressure measurement wiki lesker pumping 3_6_09 (2)
1. Pressure measurement
From Wikipedia, the free encyclopedia
•Manometer: a pressure
measuring instrument, usually limited to
measuring pressures near to atmospheric.
The term manometer is often used to refer
specifically to liquid column hydrostatic
instruments.
2. Zero reference
• Absolute pressure is zero referenced against a
“perfect vacuum” (it-the value-is equal to gauge
pressure plus atmospheric pressure).
• Gauge pressure is zero referenced against
ambient air pressure; it-the value-is equal to
absolute pressure minus atmospheric pressure.
Negative signs are usually omitted; often
expressed as “inches of vacuum” or some such.
Examples?
• Differential pressure is the difference in
pressure between two points. Examples of uses?
3. Zero reference
• Absolute pressure
• Gauge pressure
• Differential pressure
• Are these distinctions:
– Meaningful?
– Accurate?
– Useful?
– Explain and discuss
5. Error? In Wikipedia???
• “In American and Canadian engineering,
stress is often measured in kip. Note that
stress is not a true pressure since it is not
scalar. “
• Really! “kip” stands for kilopounds. Is this
a unit of stress or pressure?
6. Is pressure related to stress?
• Pressure is a property of fluids, which, by
definition cannot support a shear.
• Stress comes in three forms:
– Tensile/compressive stresses are related to forces
normal to a surface
– Shear stresses are in the plane of the surface
– The bulk modulus is related to hydrostatic forces
(pressure)
• Except for the fact that the bulk modulus is
measured by applying hydrostatic pressure,
stress relates to properties of solids
• Stress is not relevant to discussions of pressure
7. Hydrostatic Gauges
• Hydrostatic gauges (such as the mercury
column manometer) compare pressure to the
hydrostatic force per unit area at the base of a
column of fluid. Hydrostatic gauge
measurements are independent of the type of
gas being measured, and can be designed to
have a very linear calibration. They have poor
dynamic response.
• Why?
8. Piston
• Piston-type gauges counterbalance the
pressure of a fluid with a solid weight or a
spring. For example dead-weight testers
used for calibration and
Tire-pressure gauges.
• How do you get from spring displacement
to pressure?
• How do you “calibrate” a tire gauge?
10. Bourdon Gauge (Mechanical)
Key concept: pressure
difference across different
areas of inner and outer
surfaces causes crescent to flex
11. Diaphragm (Ancient, mechanical)
If each element is sealed
with a known, fixed internal
pressure, flex will depend
on pressure change on
outside. Stacking amplifies
effect!
12. Diaphragm (modern, capacitance)
• resistive (strain gauge)
• inductive
• capacitive - The deflection of the piston is often one half
of a capacitor, so that when the piston moves, the
capacitance of the device changes. This is a common
way (with proper calibrations) to get a very precise,
electronic reading from a manometer, and this
configuration is called a capacitive manometer vacuum
gauge.
• “This is also called a capacitance manometer, in which
the diaphragm makes up a part of a capacitor. A change
in pressure leads to the flexure of the diaphragm, which
results in a change in capacitance. These gauges are
effective from 10−3
Torr to 10−4
Torr.” [Nonsense! MKS
sells capacitance gages over the range 0.01 – 155,000
Torr!]
• piezoelectric/piezoresistive
13. Capacitance Manometer
• A = Annular electrode
• D = Disk electrode
• S = Substrate
• G = Getter (in vacuum
space)
• Differential capacitance
between annulus and
disk depends on
pressure difference
between Test Chamber
and “Getter”.
14. Thermal conductivity gauges
• Thermal conductivity of gases depends on density
• Gas density is directly proportional to pressure at a given
temperature.
• A thermocouple or Resistance Temperature Detector
(RTD) can then be used to measure the temperature of
the filament.
• This temperature is dependent on the rate at which the
filament loses heat to the surrounding gas, and therefore
on the thermal conductivity.
• Common variant: Pirani gauge
– uses a single platinum filament as both the heated element and
RTD. These gauges are accurate from 10 Torr to 10−3
Torr, but
they are sensitive to the chemical composition of the gases
being measured.
15. Heat Transfer of Gases
• Conductivity is
linear in
pressure over
about 2 orders
of magnitude.
• Viscous flow
regime
• Pirani and
thermocouple
gauges
16. Ionization gauge
• Most sensitive gauges for very low
pressures (high vacuums, AKA "hard"
vacuums).
• Sense pressure indirectly by measuring
the electrical ion current produced when
the gas is bombarded with electrons.
• Ion density will be proportional to gas
density.
• The calibration of an ion gauge is unstable
and dependent on the nature of the gases
being measured, which is not always
known.
17. Ionization gauges
• Useful range: 10-10
- 10-3
Torr (roughly 10-8
- 10-1
Pa)
• Hot cathode version: an electrically heated
filament produces an electron beam. The
electrons ionize residual gas molecules. Ion
current current depends on the number of ions,
which depends on the pressure in the gauge.
• Cold cathode version: the same, except that ions
are produced by electrons from a high voltage
electrical discharge.
18. Making vacuum: pumps
• Two kinds:
– Displacement
• Remove gas from system by putting it somewhere
else
• Works like a water pump
– Entrapment
• Remove gas molecules from vapor
• “Gas” remains in the system
• Works like a garbage can? Better example?
19. Rotary vane pump
Exhaust Intake
Note that the vanes
are spring-loaded,
so the expand and
contract while traversing
the eccentric hole.
The workhorse of
physics labs for the
last…70?... years!
It was invented
by Charles C. Barnes
of Sackville, New Brunswick
who patented it on
June 16, 1874.[1]
20. Scroll Pump
Intake
Exhaust port in center
Blue area rotates
counterclockwise
with silver area sprung
against it. Volume
between parts decreases.
21. Oil Diffusion Pump
Text
Vapor jet entrains residual
gas molecules.
Molecular flow required.
Hence must be backed.
“It’s all about momentum
transfer!”
Te
xt
Boiler
Water
cooling