Centrifugal pump for de-watering

Abstract

A method of de-watering during intermittent dry running periods with a self-priming centrifugal pump is presented. Centrifugal pumps, as opposed to diaphragm pumps, are advantageous because they are less expensive and can provide greater capacity. The shaft seals are sensitive, however, to frictional heating when water flow is interrupted. In some situations, this fractional heating may desiccate self-priming. The inventive concept provides a continuous stream of pressurized water moving through the pump to cool the seal and sustain priming capability without substantially impairing the ability of the pump to resume wet operation.

1 . A method of dewatering an intermittently dry pool, comprising the steps of:
 providing a self-priming centrifugal pump having inlet and discharge ports and an impeller;   connecting the impeller to an engine through a shaft fitted with a seal providing water-tight isolation, the impeller creating head manifest as suction in the inlet port;   establishing fluid communication between the inlet port and the pool; and   introducing a means for continuously cooling the shaft seal without occluding the suction, whereby degradation of the seal by heat of friction is averted.   
     
     
         2 . The method of dewatering of  claim 1 , wherein the means for continuously cooling is provided by a pressurized source of liquid introduced to the inlet port at a fraction of the pump capacity, the liquid streaming continuously regardless of dry operation. 
     
     
         3 . The method of dewatering of  claim 2 , wherein the liquid is water under line pressure. 
     
     
         4 . The method of dewatering of  claim 2 , wherein the fraction of the pump capacity is defined by the pressurized source delivering 3-10 gpm to a centrifugal pump operating at 100-150 gpm. 
     
     
         5 . A method of dewatering an intermittently dry pool, comprising the steps of:
 providing a self-priming centrifugal pump having inlet and discharge ports and an impeller;   connecting the impeller to an engine through a shaft fitted with a seal providing water-tight isolation, the impeller creating head manifest as suction in the inlet port;   establishing fluid communication between the inlet port and the pool; and   introducing a pressurized source of liquid to the inlet port at a fraction of the pump capacity, whereby a continuous stream of fresh liquid is provided through the pump to prevent the seal from overheating and degrading.   
     
     
         6 . The method of dewatering of  claim 5 , wherein the liquid is water under line pressure.