Position Pressure Transmitter

The pressure is the same regardless of whether the transmitter/gauge is upside down, right side up, or sideways.

It's much easier to read right side up.

The pressure transducer itself will not care where it is placed. It will report the pressure at that location. Knowing the pressure at multiple locations can inform what is happening in the system.

The PT should be located at approximately the same elevation as the tapping point.

Then, no correction would be needed to account for pressure loss or gain, due to fluid/specific gravity weight and elevation.

It probably doesn't really matter.

Friend,

Maybe the fluid when the transmitter is in the top tapping point is Gas, this is a possibility....

How sure are you if in that case the fluid was liquid?

Best regards
JP

The conventions for mounting pressure instruments are based on the high probability of
- entrained gas or air in a liquid line or
- liquid/condensate in a gas line

Liquid in a gas line can collect in the impulse line when the instrument is mounted below the process line, and its presence adds error to the gas pressure measurement.
Air or gas entrapped in liquid-sensing lines can cause false pressure readings, sluggish response, and extraneous noise as a result of acoustic resonances. Air in a liquid line tends to collect at a high elevation point in impulse piping/tubing connected to an instrument mounted above the liquid process line.

I've seen an error of 30cm due to air trapped in a liquid impulse line on a hydrostatic level indicator on a 2.5m tall tank. I liken the error to when air gets into a vehicle's hydraulic brake line and the brake pedal gets 'squishy'. The amount of work needed to compress the air and produce braking action is considerably more than than that required when only liquid is in the line.

As to why instruments are located above process liquid lines it's because it was done that way. The percentage of error from an entrained air cushion in a liquid line decreases as the line pressure increases. The error is much less significant on a pipeline at 10 bar pressure than on a 0.25 bar bellows gauge indicating level of a 2.5m water tank.

Position, location doesn't matter for either gases or liquids. In a closed pressurized system they are both at the same pressure. Read one under the liquid/gas level or above in the gas section and they will give you the same readings.

Good Luck, Old Saltl

Dear All,

I'm sorry very too late response, it turns out the liquid is hydrocarbon liquid, that's ehy position of pressure transmitter on above tapping point. Thanks for all you are response.

Best Regards,

Andra. S