Condensate Return Pumps 2016 by Watson McDaniel

More catalogs by Watson McDaniel | Condensate Return Pumps 2016 | 69 pages | 2016-05-24

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Page 27 of Condensate Return Pumps 2016

pump trap combinations why use a pump-trap heat exchanger system with steam trap problem condensate backs up into heat exchanger temperature controller steam control valve pumping traps 50 psig condensate return steam temp sensor hot water outlet inlet pressure the diagram shows a temperature control valve delivering steam to a heat exchanger that is using steam to heat water condensate formed in the heat exchanger is being discharged through the steam trap into the condensate return line this particular application demonstrates what happens when the return line is elevated and/or pressurized the plant steam pressure on the inlet side of the control valve would be adequate to purge push the condensate through the trap and into the return line however the steam pressure in the heat exchanger is controlled by the valve and is dependent on the demand of the system when the demand for hot water is low the steam pressure in the heat exchanger falls below the back pressure and the system backs up with condensate creating unstable temperature control and waterhammer this undesirable condition referred to as stall occurs when the steam pressure in the heat exchanger falls to or below the system back pressure due to a decrease in the demand flow rate of hot water condensate return line pressure steam pressure of 10 psig in heat exchanger cannot overcome total back pressure causing condensate to back up condensate backs up into heat exchanger total back pressure 15 psig f&t trap cold water inlet if inlet pressure is not higher than back pressure condensate will back up back pressure heat exchanger system with pumping trap solution use a pump-trap to avoid condensate back-up improve temperature control to eliminate condensate backing up stall the standard float trap is replaced with a pump-trap when steam pressure in the heat exchanger is greater than the back pressure the steam pressure will push the condensate through the pump-trap and it functions like a standard float-operated trap when the steam pressure to the heat exchanger drops below the back pressure the condensate backs up inside the pump-trap raising the float when the trip point of the mechanism is reached the high-pressure steam valve will open to drive the condensate out steam control valve condensate return line pressure 50 psig temperature controller steam pressure 50 psig condensate return steam temp sensor balancing line hot water outlet higher pressure steam used to pump condensate can overcome back pressure pump exhaust cold water inlet total back pressure 15 psig condensate drains by gravity into pump tank solution steam trap is replaced with pump-trap combination inlet check valve pump trap outlet check valve tel 610-495-5131 • pottstown pa • usa •• www.watsonmcdaniel.com 155