Deadweight tester

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]

[1]

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 :

  1. gas operated gas lubricated PCU's
  2. gas operated oil lubricated PCU's
  3. oil operated oil lubricated PCU's

See also
Wikimedia Commons has media related to Deadweight testers.

References
  1. Fluke Corporation. "Pressurements PressCal Deadweight Tester Software" (PDF). Retrieved 21 November 2019.
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