Pressure Indicator range 3

[techman81]

Hi guys,

I need to specify the pressure range for indicator after the glycol pump with PSV set pressure 30,5 barg and normal discharge pressure 12,5 barg.

I thought that 60% of the set pressure would be ok as a maximum,but I am not sure.

Could you please guide me how should I set up range for this PI?

thanks,

thechman81

 

[JLSeagull]

You could calibrate a pressure transmitter for a range limited to 60% of the PSV set pressure but not a mechanical gauge. With a transmitter I would normally cover the maximum. If the operating pressure is less than 10% of the maximum I might suppress the range. However, the gear and sprocket on a pressure gauge are physically limited to about 125% of the full scale reading. The pointer would essentially fail if you selected a range near 60% of the PSV setting and such pressure occured.

In your example you should specify the pressure range for a mechanical gauge after the glycol pump to exceed the PSV set pressure 30,5 if practical. See if a common range in a compound gauge is suitable. 35 barg and 41 barg correspond to common psig ranges. I would recommend the 35 bar scale if available. Consider a liquid filled gauge downstream of a pump.

Devices called gauge savers limit the pressure that the gauge sees. I have know people who applied these in your situation. I would exclude devices that show a different pressure than actually exists.

 

[BenThayer]

the general rules of thumb is that you should operate at no more than 2/3rd's of your range or put another way, you want to have normal operation within the middle third of your gauge.

but absolutely, have the max range above the PSV setting. otherwise you might be flying blind some of the time.

 

[Ashereng]

Yup, I agree with Ben.

For both gauge and transmitter, set the range to cover the PSV. Your operating point is roughly in the middle third anyway.

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Albert Einstein
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