A dead weight tester apparatus uses weights to apply pressure to a fluid for checking the accuracy of readings from a pressure gauge. A dead weight tester (DWT) is a calibration standard method that uses a piston cylinder on which a load is placed to make an equilibrium with an applied pressure underneath the piston. Deadweight testers are secondary standards which means that the pressure measured by a deadweight tester is defined through other quantities: length, mass and time. Typically deadweight testers are used in to calibrate pressure measuring devices.
Formula
The formula on which the design of a DWT is based basically is expressed as follows :
| p | = | F / A | [Pa] |
where :
| p | : | reference pressure | [Pa] |
| F | : | force applied on piston | [N] |
| A | : | effective area PCU | [m2] |
Piston cylinder design
In general there are three different kind of DWT's divided by the medium which is measured and the lubricant which is used for its measuring element :
- gas operated gas lubricated PCU's
- gas operated oil lubricated PCU's
- oil operated oil lubricated PCU's
See also
Wikimedia Commons has media related to Deadweight testers.- Blaise Pascal
- Calibration
- Force gauge
- Piezometer
- Pressure measurement
- Pressure sensor
- Vacuum engineering
References
Fluke Corporation. "Pressurements PressCal Deadweight Tester Software" (PDF). Retrieved 21 November 2019. https://dam-assets.fluke.com/s3fs-public/PressCalumeng0000.pdf ↩