Centrifugal Pump Capability in Closed Loop
Centrifugal Pump Capability in Closed Loop
(OP)
I have a diesel engine-generator which has its own engine-driven 390 gpm centrifugal coolant pump with about 10 psi external restriction capability.
The problem is that this application requires the radiator to be 15 feet below the engine's pump. There will be a surge/expansion tank mounted above the engine with fill and vent lines(highest point in the system). The expansion tank will have a 14 psi pressure relief cap. The 50/50 water/glycol mix exits the engine at 200 Deg F, goes through 6" pipes (2 psi loss)passes through the radiator (about 4 psi loss) - now at 175 Deg F -and, hopefully returns to the engine. This is a closed loop system. The restrctions do not exceed the capability of the pump. But, it is 15' and it is a hot liquid.
Will the mixture flash to steam when the engine's centrifugal pump pulls on the liquid? Will it work without an additional pump in series with the engine's pump? Any suggestions?
The problem is that this application requires the radiator to be 15 feet below the engine's pump. There will be a surge/expansion tank mounted above the engine with fill and vent lines(highest point in the system). The expansion tank will have a 14 psi pressure relief cap. The 50/50 water/glycol mix exits the engine at 200 Deg F, goes through 6" pipes (2 psi loss)passes through the radiator (about 4 psi loss) - now at 175 Deg F -and, hopefully returns to the engine. This is a closed loop system. The restrctions do not exceed the capability of the pump. But, it is 15' and it is a hot liquid.
Will the mixture flash to steam when the engine's centrifugal pump pulls on the liquid? Will it work without an additional pump in series with the engine's pump? Any suggestions?





RE: Centrifugal Pump Capability in Closed Loop
I'm not sure about this particular application, or your whereabouts, but in most jurisdictions that subscribe to ASME, you can have 30 PSIG relief valves on hot water heating systems without falling under various act and code requirements.
Also remember to have the glycol checked annually. It can degrade and turn acidic. There are cases of neglected glycol eating expensive things like hot water boilers, and heavy truck diesel engines.