Fuel Oil Return Valves

[MinnesotaSlinger]

I'm working on the design of a fuel oil piping system with multiple emergency generators and multiple tanks. I'm wondering about valves in the return and overflow lines back to the tanks. I understand that there should be no valves in the return and overflow paths. However, if no valves are installed in the individual lines to each tank (that is, not the common return and overflow lines), how can I isolate a tank due to tank maintenance, removal, or failure? It would seem that each tank should have an isolation valve to prevent oil from the return or overflow line from returning to the affected tank. But if each tank has an isolation valve, someone could shut all of these isolation valves, block the returning oil, and possibly damage the system. It might not be as likely as if there were one valve in the common line, but it's still possible. Also, one of our tanks will not be initially installed, so it would seem to me valves must necessarily be placed in the capped return and overflow lines to the future tank. If someone could shed some light on the appropriate way to ensure proper return of fuel oil while allowing a tank to be isolated, I'd appreciate it. Thanks.

 

[vpl]

Make the maintenance valves manual ones and put a lock on them. Then the only way for all of them to be closed is sabotage. If you've got sabotage going on, you have much bigger problems than can be solved here.

Patricia Lougheed

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[BigInch]

Spec blinds.

"We have a leadership style that is too directive and doesn't listen sufficiently well. The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward CEO BP
"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.liv

 

[TheBlacksmith]

We always used suction and return valves ganged together. Either they were both open and you had fuel supply and return or they were both closed. Another dnager is drawing from one tank and returning to another until it overflows.