Propane Refrigeration Circuit 1

[gwanju]

I have a refrigeration circuit with three stage compressorThere is an orifice in the bypass line. The line is the feed to the comressor suction KOD. I would like to know the purpose of the orifice.

 

[MortenA]

I would say its a pressure equlisation line - so that you can open the main block valve with a high dP, thats also why there is a dP across the valve. The orifice is to limit the flow across the by-pass when the dP is high.

Best regards

Morten

 

[dcasto]

Since the line is used to purge and prussure up the system you need to control the flowrate. Most people use an expensive globe valve sized with a proper orifice to obtain a specified flowrate. Using a properly sized restrictive orifice downstream of a gate vale or ball vale saves money and allows for resizing if the flowrateneeds to be changed in the future.

As a side note, our engineering standards didn't allow purging or pressuring up ethylene systems any faster than 25,000 pounds per hour. A 1/2" orifice in the 2" or 3" lines worked fine.