In chemical plants and refinery service normally two pumps are installed, one running and the other stand-by. In the discharge of each centrifugal pump an isolation valve and non-return are provided. Sometimes the isolation valve is installed before the NRV, and sometimes the other way. Please indicate the correct arrangement considering maintenance safety. Please also indicate whether the NRV is to be installed in horizontal or vertical part of the piping.
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Ross Mackay Forum Moderator 93 Posts
Re: Correct arrangement for isolation and NRV valves2 August 2006 at 1:29pmNormal piping practice would place the non-return check valve upstream of and closer to the pump than the isolating valve. It doesnt matter whether its in a horizontal or vertical arrangement. Prior to both valves, a concentric pipe increaser should be installed.