What is a deadweight tester used for?

• A. Measures temperature with a fixed resistor.
• B. Calibrates flow meters using a flow loop.
• C. Detects leaks via pressure decay.
• D. Uses known traceable weights to apply pressure to a fluid for checking the accuracy of pressure gauge readings.

Answer: (D)

A deadweight tester works on the principle of balancing known weights against fluid pressure to establish an accurate, known pressure. It uses a piston with a precisely known cross‑sectional area inside a sealed chamber. By placing calibrated, traceable weights on a force mechanism, you generate a pressure equal to the total weight (force) divided by the piston area (P = F/A). The gauge or pressure sensor under test is connected to the fluid side, so it reads this exact pressure. Because the weights are traceable to standard references, the pressure generated is well defined and can be used to verify or adjust the gauge’s accuracy across a calibration range. This is a static, direct-pressure calibration method, not tied to temperature sensors, flow loops, or leak-detection techniques.

Other methods described involve different principles: measuring temperature with a fixed resistor relates to temperature sensors like RTDs; calibrating flow meters uses a flow loop; and detecting leaks via pressure decay uses how quickly pressure falls, not a known static pressure applied with weights.