Cooling Tower Pumping and Piping Guide
Correctly piping the suction and discharge of your cooling tower/condenser water pump is critical. Some fairly catastrophic events can occur if either is improperly installed.
Starting with the suction piping, it is important to take precaution to avoid air pockets – which can destroy a pump in pretty short order. Remember, cooling tower water is full of air, so air in the piping is a given. You just have to make sure to avoid any sudden pressure drops between the tower and the pump suction, otherwise the air could “pop out” of the water, enter the pump, and destroy a pump shaft. Another potential problem, depending on the temperature of the water, is the possibility of cavitation, should the pressure drop be so great that some amount of water flashes to steam upon entering the pump.
Tower pumping does not present great difficulty in terms of good pump application. This is because of a normally high order of application safety factor. Troubles do occur occasionally, however, and these troubles can be classified as caused by:
- Incorrect pump head estimation.
- Pump cavitation and loss of pumping ability, as caused by inadequate pump suction pressure.
- Air in pump suction; as caused by tower pan vortex, pan drain down or faulty bypass.
- Unstable pump operational points as caused by:
a. Improper application of tower bypass controls.
b. High pressure drop tower spray nozzles in combination with tower bypass.
- Inadequate maintenance procedures causing:
a. Plugged suction strainer.
b. Lack of tower treatment with consequent fouling of the condenser.
It is intended that each potential trouble source be evaluated so that the necessary design safeguards can be erected against operational problems.
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