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Deadweight tester

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Dead weight tester, Type PD23, Nagano Keiki Co., Ltd.

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

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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

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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

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References

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