A dead weight tester is an instrument that calibrates pressure by determining the weight of force divided by the area the force is applied. The formula for dead weight testers is pressure equals force divided by area of where force is applied.
A dead weight tester works by using a piston cylinder which a load is placed to create an equilibrium with applied pressure. Dead weight testers are usually used in calibration laboratories to calibrate pressure transfer standards. Dead weight testers, also referred to as primary standards, generally express accuracy as a percent of the indicated reading. Many testers are available. To select the proper tester, consider the tester's accuracy, the type of test fluid used, the task being performed and the pressure ranges of the instruments tested.
Before using a dead weight tester, consider the following:
- Users should be familiar with the device and the pressures should not exceed their ratings.
- Fittings used to connect the tester to the device being tested must exceed the pressure rating of the tester.
- Do not connect to a pressure source such as a well or pressurized tank.
- Test fluid should be compatible with process fluid.
- Weights exceeding maximum pressure should be stacked on the weight carrier prior to applying pressure.