What are the Steps Involved in Calibrating Pressure Gauge?

Today, a variety of transmitters are being used to measure parameters, such as temperature, pressure, flow, level, etc. An instrument, which is used to measure the pressure of a fluid is referred as a pressure gauge. These gauges are used in several industries. However, for an accurate reading of the fluid pressure, these instruments require proper calibration. Now, you can calibrate the instrument by using diverse tools, or methods. Yet, the most widely used method is by using the dead weight tester. What is this tester? How these pressure gauges are calibrated using dead weight testers? Are you eager to find out? Please read the following post, which explains the calibration process, in steps.

What is a Dead Weight Tester?

First things first. To understand the calibration process, you first need to know what a dead weight tester actually is. In simple words, it is basically an apparatus, which uses calibrated weights. These weights help check whether the readings shown by the pressure gauges are accurate or not. Fluid, connection port, and a weight and piston are the main components of these testers. The reference pressure of these testers is calculated by the formula –

p = F / A

Where,

• p: Reference Pressure (Pa)
• F: Force applied to the Piston (N)
• A: Area PCU (m²)

How is Pressure Gauge Calibrated Using Dead Weight Tester?

To calibrate a pressure gauge using dead weight tester assembly requires one to follow certain steps for a precise calibration. The steps involved in the calibration process are as follows:

• Step 1: Making the Arrangements

  This is the very first step of the entire process. Before you start the calibration of pressure gauges, make sure that the device is placed at a uniform level. The workbench should be stable for proper operation. Once you ensure this, attach the pressure gauge to the test port.

• Step 2: Fixing the Zero Error

  You do not want zero error to peek in while calibrating the gauge. Thus, it is advisable to confirm zero reading on the pressure gauge. Adjust the gauge, so that it is reading zero. If this is not done, then the gauge might get calibrated with some zero error still present.

• Step 3: Placement of the Weight

  This is the step, from which the actual calibration begins. Select a reference weight, and keep it on the vertical piston of the dead weight tester assembly.

• Step 4: Moving the Piston

  Other than the vertical piston, there is one more piston – a horizontal one. Turn the handle attached to this piston. Do this, until a point is reached, where the piston and the weight are freely supported by oil. Now, turn the vertical piston, so that it starts floating freely.

• Step 5: Recording the Readings

  Let the system stabilize for some time. Now, once the system gets properly stabilized, it is the right time to record the reading of the gauge and weight.

• Step 6: The Final Step

  This is the final step of calibration. Follow the steps 3 through step 5, and go on applying pressure. Do not stop until maximum pressure is reached. Now, go on reducing the weights one by one till the point the gauge pressure reads zero. Check whether there is an error in the gauge pressure reading. If the error is within the accuracy limits, then there is no need to worry. Your gauge is calibrated successfully.

A wide range of pressure measuring devices can be calibrated using these dead weight testers. You can easily calibrate industrial pressure gauges, and pressure transmitters with these testers. To know more about pressure gauges, and their calibration, you can get in touch with the experts. The Transmitter Shop is one such experienced player, which can help you calibrate your pressure gauges with great accuracy.