PI
A pressure indicator is also known as a pressure gauge. A pressure indicator is a field instrument that requires little to no maintenance.
How it Works
Process Pressure Gauges function when the process fluid enters a Bourdon Tube or similar enclosure. The pressure causes the Bourdon Tube to deflect in a known way. The bourdon tube may directly affect the needle to show the pressure or it may connect to a gear box to relay the pressure.
Specifying
When choosing a PI, it is most important to select the correct materials that are in contact with the process. In steam applications special options may need to be selected.
Sometimes, when the pressure indicator is installed downstream of a pump or in a service where there is high vibration, it may be necessary to have the case filled with fluid such as glycol or other oil. Glycol helps dampen the movement of the needle.
Common pressure ranges are listed below. When selecting a pressure gauge, it is good practice to select a gauge where the operating pressure is halfway between the indicated range. For example, when operating pressures are 60 psi, a 0-100 psi range is appropriate.
Pressure Ranges
| PSI |
|---|
| 0-15 |
| 0-30 |
| 0-60 |
| 0-100 |
| 0-160 |
| 0-200 |
| 0-300 |
| 0-400 |
| 0-600 |
| 0-800 |
| 0-1000 |
| 0-1500 |
| 0-2000 |
| 0-3000 |
| 0-5000 |
| 0-10,000 |
| 0-20,000 |
| 0-30,000 |
| 0-50,000 |
| 0-80,000 |
| 0-100,000 |
