This guide provides an overview of measuring vacuum pressure including suggested vacuum measurement products and question & answers relating to using and selecting vacuum measurement sensors & instrumentation.
Vacuum is the range of pressure which lies between zero absolute pressure (perfect vacuum) and atmospheric pressure.
DMP331P Hygienic Flush Pressure Transmitter - Sanitary pressure sensor wth exposed diaphragm with no crevices for high temperatures up to 300 Degrees Celsius in ranges from 100mb up to 40 bar gauge or absolute
DM01 Multi-Range High Accuracy Pressure Gauge - High precision digital pressure gauge with 0.1% full scale accuracy, exchangeable pressure range modules from 100 mbar (1.5 psi) up to 400 bar (6000 psi).
IMP Low Cost Pressure Sensor - Versatile low price pressure sensor with a wide selection of electrical and mechanical options for customisation.
DMK457 Marine Approved Pressure Transmitter - Marine approved pressure transmitter with 4-20mA current loop output for shipbuilding with optional CuNiFe housing for sea-water compatibility
DPS300 User Switchable Pressure Range, Volts or Current Output Low DP Sensor - The DPS 300 is a low range HVAC differential pressure sensor. The lowest possible pressure range is 0...100 pascals. 2 or 3 switchable pressure ranges, plus volts or current output are included with most standard configurations.- DL01 Leak Testing Pressure Data Logger - The DL 01 leak testing pressure logger series delivers elite performance for the most demanding calibration, test technology, leak testing, and pipeline monitoring tasks.
- ATEX approved negative 10 mbar vacuum pressure transmitter
- Portable vacuum sensor tester for industrial control loop set-point validation
- 400 mbar absolute (not relative) battery supplied vacuum sensing display
- -100 mbar digital vacuum gauge
- Vacuum gauge for minus 150 mbar range with a 0.1 mbar display resolution
- Digital vacuum/pressure recorder to replace circular paper chart
Vacuum Pressure Transmitters - Choose vacuum pressure transmitters for measurements over the low vacuum range of 25 to 760 Torr, using a absolute or negative gauge reference vacuum range.
Vacuum, Suction Pressure Data Loggers, Recorders - Select vacuum data loggers for precise recording of negative suction and absolute pressures. Ideal for process analysis, test reports, and system validation in industrial and research settings.
Vacuum, Suction, Negative Pressure Gauges - Explore digital gauges using piezoresistive & capacitance sensors for low to partial vacuum, suction, and negative pressure. Ideal for industrial & lab applications.
Vacuum Pressure Transducers - Explore vacuum pressure transducers with voltage outputs (0-5V, 0-10V, 0.5-4.5V). Select absolute or gauge references for partial/full vacuum ranges.
Vacuum Range Calibration Equipment - Maintain the accuracy of your vacuum sensors, gauges, and switches with high-quality vacuum calibration equipment.
Find out more about Vacuum to determine which product options and capabilities will best meet your application requirements.
Vacuum pressures in the range of a few millibars up to atmospheric pressure are easily measured by diaphragm based pressure measurement instrumentation. In this range of partial vacuum pressures it is common to measure the vacuum using either a negative gauge reference or an absolute reference pressure sensing device. The choice of a negative gauge or an absolute reference will depend on whether you are interested in measuring the pressure compared to atmospheric pressure or to a perfect vacuum.
High vacuum pressures are very close to zero absolute pressure and much harder to measure with diaphragm type instrumentation. At high vacuum pressures it is necessary to use different sensor technology which is based on ionisation or thermal conductivity measurement principles.
Vacuum measurement is critical across diverse industries and research fields. Users often include design engineers developing new equipment, installation engineers setting up vacuum systems, control and instrumentation engineers integrating sensors into automated processes, and maintenance engineers ensuring continued optimal performance. These professionals work in sectors like semiconductor manufacturing, where precise vacuum control is vital for fabrication processes; aerospace, where vacuum is used in altitude simulation and component testing; and pharmaceutical production, where vacuum is essential for sterilization and drying. Research laboratories also rely heavily on vacuum technology for experiments in physics, chemistry, and materials science. Geographically, these applications span the globe, wherever advanced manufacturing, research, or specialized processes requiring vacuum are conducted.
Questions & Answers
0 bar absolute = -1 bar gauge
Is zero bar absolute the same as minus 1 bar gauge?
No, only when atmospheric pressure happens to correspond exactly to 1 bar absolute which rarely happens.
Does 1 bar cover the vacuum range
Is a minus 1 bar range adequate for measuring over the vacuum range?
For most applications yes, especially if measuring low suction pressures. If measuring a very high vacuum to some degree of accuracy, it is best to measure with a positive absolute range, since a negative gauge device will give different readings due to the changes in atmospheric pressure.
Technology used to measure over vacuum range
What type of sensing technology is used for measuring in the vacuum range?
For vacuum ranges 0-100 mbar up to 0-1000 mbar absolute it is usual to use a lower cost strain gauge diaphragm type. For ranges from 0-1 mbar up to 0-1000 mbar absolute, capacitive or inductive sensing techniques are the typical methods for measuring higher vacuums more precisely and with less drift. For ultra high vacuum ranges below 0-1 mbar it is not possible to measure this low a pressure with electromechanical devices and it is necessary to use less direct methods such as thermal conductivity and ionisation techniques.
Vacuum units
What pressure units are used for measuring vacuum pressures?
Vacuum level variations in a pumped chamber
Will the vacuum level be the same at the opposite end to the suction end of a chamber where a vacuum pump is connected?
If there is flow of gas, then you should expect there to be some difference in pressure, but it will depend on flow rate, size of volume and any restrictions between pump and end of chamber. If the suction pressure is static with no flow, then the vacuum pressure will equalise it all points.
Vacuum Gauge vs Vacuum Absolute
What is difference between reading pressure in vacuum gauge and vacuum absolute?
Vacuum gauge is measured from ambient air pressure in the negative direction. So for example at ambient air pressure the vacuum reading is 0 bar gauge and if a suction pressure of 0.25 bar is applied, the vacuum reading will be -0.25 bar gauge.
Vacuum absolute is measured from a perfect vacuum in the positive direction. At ambient air pressure the vacuum reading will be the barometric air pressure, let’s use 1.015 bar absolute as an example. If a suction pressure of 0.25 bar is applied the vacuum reading will be 0.765 bar absolute.
Related Help Guides
- Measuring vacuum with negative gauge or absolute ranges
- What is the difference between vacuum and absolute pressure
- What does negative and positive gauge pressure mean
- Measuring negative pressure using a positive differential pressure range
- Measuring vacuum as a negative gauge pressure using a dp sensor
- Can you measure vacuum using a gauge pressure range
Related Product and Application Guides
Related Technical Terms
Related Online Tools
Related Product Types
- Vacuum Pressure Transmitters
- Vacuum, Suction Pressure Data Loggers, Recorders
- Suction Pressure Transmitters
- Vacuum, Suction, Negative Pressure Gauges
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