01. How to ensure proper alignment of the compressor nozzle and piping?


	Applies To

	Product(s):	AutoPIPE
	Version(s):	2004, XM, V8i
	Environment:	N/A
	Area:
	Subarea:
	Original Author:	Bentley Technical Support Group
	Date Logged & Current Version	Feb. 2015 09.06.01.10

Problem:

I have a basic question regarding modeling piping in a compressor station.

Typically, the compressor is installed first and properly leveled and grouted. The pipe (discharge and suction) is installed next and all adjustments to the piping are performed until the mating faces of the pipes and the compressor nozzles are accurately aligned. At this point all the gravity load from the empty pipe is carried by the supports on the pipes and no load is transferred to compressor nozzle. After assuring that the pipe and the nozzles are accurately aligned, the pipe is connected to the compressor nozzles. At this instant no load from the pipe is carried by the compressor nozzle. When the system is in operation the compressor nozzle will be subjected to all the loads (temperature, pressure, gas in the pipe) that occur in the system subsequent to the initial connection between the pipe and the nozzle. How is this scenario correctly modeled so that when the reactions are printed, it will show zero reactions at the compressor nozzle?

Answer:

This has already been replied to in Be Communities:

http://communities.bentley.com/products/pipe_stress_analysis/f/275801/t/61397.aspx

The adjustments that you mention before connecting to the pump may need to be modeled to insure no displacement under gravity load. Imposed support displacements or cut-short or similar adjustments needs to be added in your model to probably predict what will happen when adding the thermal load. If a physical anchor is added on suction and discharge then the pump will not get the loads.