Apparatus and method to provide run-dry protection to semi-positive and positive displacement pumps

Abstract

Apparatus and method to provide run-dry protection to semi-positive and positive displacement pumps is disclosed, including a resettable fuse placed in line with the motor of said pump to interrupt the supply of electrical power to the pump in response to sensing a run-dry condition. The resettable fuse prohibits pump operation until manual resetting, which occurs only upon interrooting and re-applying electrical power to the resettable fuse.

What is claimed is:  
     
         1 . A protector device to protect a motor-pump assembly having a pump to pump fluids and a motor to drive said pump, said protector device comprising: 
 a resettable fuse device placed in line with a power source supplying electrical power to said fuse and said motor-pump assembly, said fuse adapted to interrupt supply of electrical power to said motor-pump assembly in response to sensing a run-dry condition and reset only upon interruption and re-application of the supply of electrical power to said fuse.    
     
     
         2 . The device of  claim 1 , said fuse device further comprising: 
 a plurality of resettable fuses connected to each other in a parallel circuit configuration.    
     
     
         3 . The device of  claim 1 , wherein said run-dry condition comprises an increase in current level within said fuse.  
     
     
         4 . The device of  claim 1 , wherein said fuse is disposed within the housing of the motor pump assembly.  
     
     
         5 . A method for protecting a motor-pump assembly having a pump to pump fluids and a motor to drive said pump, said method comprising: 
 interrupting the supply of electrical power to said motor-pump assembly in response to sensing the occurrence of a run-dry condition; and    manually resetting said fuse from a remote location by interrupting and then reinitiating electrical power to said fuse.    
     
     
         6 . In a positive and/or semi-positive displacement pump having a motor and pump disposed within a housing, the improvement comprising: 
 a resettable fuse disposed within said housing and placed in line with said motor;    said resettable fuse providing an automatic shut-off for said motor upon encountering a run-dry pump condition, which fuse remains open until electrical power is discontinued and subsequently re-initiated to said fuse.