Modular stub shaft assembly for a centrifugal pump

Abstract

An assembly is provided for interconnecting a drive shaft of a motor to an impeller of a pump. The assembly includes a stub shaft having an end with a fastener for connecting the stub shaft to an impeller and an opposite end in the form of a sleeve having an inner diameter defining a cavity. The assembly also includes a motor shaft sleeve having an end received within the cavity of the stub shaft and an opposite end in the form of a sleeve having an inner diameter defining a cavity therein for receiving, engaging and being secured to the drive shaft of the motor. The inner diameter of the sleeve of the motor shaft sleeve is smaller than the inner diameter of the sleeve of the stub shaft. A pump and a method of interconnecting a drive shaft of a motor to an impeller are also provided.

We claim: 
     
         1 . An assembly for interconnecting a drive shaft of a motor to an impeller of a centrifugal pump, comprising:
 a stub shaft having an end with a fastener for connecting the stub shaft to an impeller and an opposite end in the form of a sleeve having an inner diameter defining a cavity therein; and   a motor shaft sleeve having an end inserted and received within said cavity of said sleeve of said stub shaft and secured thereto and an opposite end in the form of a sleeve having an inner diameter defining a cavity therein for receiving, engaging and being secured to a drive shaft of a motor, said inner diameter of said sleeve of the said motor shaft sleeve being smaller than said inner diameter of said sleeve of said stub shaft.   
     
     
         2 . The assembly according to  claim 1 , wherein said sleeve of said stub shaft includes a keyway formed in the inner diameter of the sleeve of the stub shaft, wherein said end of the motor shaft sleeve inserted within said sleeve of said stub shaft includes a keyway formed in an outer diameter thereof such that the keyways of the stub shaft and motor shaft sleeve are aligned, and wherein a separate feather key is contained within said aligned keyways thereby preventing relative rotation between the stub shaft and the motor shaft sleeve. 
     
     
         3 . The assembly according to  claim 2 , wherein said keyways extend longitudinally on said stub shaft and aid motor shaft sleeve, and wherein said feather key is an elongate metal bar. 
     
     
         4 . The assembly according to  claim 2 , wherein said sleeve of said stub shaft includes a bore extending radially through the sleeve of the stub shaft, wherein said end of the motor shaft sleeve inserted within said sleeve of said stub shaft includes a bore formed in an outer diameter thereof, and wherein said bores of said stub shaft and said motor shaft sleeve are aligned and contain therein a fastener for securing said motor shaft sleeve to said stub shaft. 
     
     
         5 . The assembly according to  claim 4 , wherein said bore extending through said sleeve of said stub shaft is a threaded bore and said fastener within said bore is a dog point set screw or other fastener type. 
     
     
         6 . The assembly according to  claim 4 , wherein said sleeve of said motor shaft sleeve has at least one longitudinally-extending open slot formed therein. 
     
     
         7 . The assembly according to  claim 6 , further comprising a fastener that extends through said sleeve of said motor shaft sleeve and said slot for tightly securing said sleeve of said motor shaft sleeve to the drive shaft of the motor. 
     
     
         8 . The assembly according to  claim 4 , wherein said sleeve of said motor shaft sleeve has multiple longitudinally-extending slots thereby forming a bifurcated sleeve and wherein said bifurcated sleeve of said motor shaft sleeve includes multiple fasteners for compressing bifurcated sections of said motor shaft sleeve into tight engagement with the drive shaft of the motor. 
     
     
         9 . The assembly according to  claim 1 , wherein said sleeve of said stub shaft includes a bore extending radially through the sleeve of the stub shaft, wherein said end of the motor shaft sleeve inserted within said sleeve of said stub shaft includes a bore formed in an outer diameter thereof, and wherein said bores of said stub shaft and said motor shaft sleeve are aligned and contain therein a fastener for securing said motor shaft sleeve to said stub shaft. 
     
     
         10 . The assembly according to  claim 1 , wherein said sleeve of said motor shaft sleeve has at least one longitudinally-extending open slot formed therein and a fastener that extends through said sleeve of said motor shaft sleeve and said slot for tightly securing said sleeve of said motor shaft sleeve to the drive shaft of the motor. 
     
     
         11 . The assembly according to  claim 1 , wherein said sleeve of said motor shaft sleeve has multiple longitudinally-extending slots thereby forming a bifurcated sleeve and wherein said bifurcated sleeve of said motor shaft sleeve includes multiple fasteners for compressing bifurcated sections of said motor shaft sleeve into tight engagement with the drive shaft of the motor. 
     
     
         12 . The assembly according to  claim 1 , wherein said stub shaft and said motor shaft sleeve are made of stainless steel. 
     
     
         13 . The assembly according to  claim 1 , wherein a plurality of motor shaft sleeves are provided each having a different inner diameter defining a different-sized cavity for receiving, engaging and being secured to the drive shaft of the motor such that an appropriately-sized one of said plurality of motor shaft sleeves is selected for interconnecting the drive shaft with said stub shaft. 
     
     
         14 . A pump, comprising:
 a motor having a drive shaft;   a volute chamber (casing) having an impeller;   a stub shaft having an end with a fastener connecting the stub shaft to said impeller and an opposite end in the form of a sleeve having an inner diameter defining a cavity therein; and   a motor shaft sleeve having an end inserted and received within said cavity of said sleeve of said stub shaft and secured thereto and an opposite end in the form of a sleeve having an inner diameter defining a cavity therein for receiving, engaging and being secured to the drive shaft of the motor, said inner diameter of said sleeve of the said motor shaft sleeve being smaller than said inner diameter of said sleeve of said stub shaft.   
     
     
         15 . The pump according to  claim 14 , wherein said sleeve of said stub shaft includes a keyway formed in the inner diameter of the sleeve of the stub shaft and said end of the motor shaft sleeve inserted within said sleeve of said stub shaft includes a keyway formed in an outer diameter thereof such that the keyways of the stub shaft and motor shaft sleeve are aligned and contain therein a feather key which prevents relative rotation between the stub shaft and the motor shaft sleeve. 
     
     
         16 . The pump according to  claim 15 , wherein said sleeve of said stub shaft includes a bore extending radially through the sleeve of the stub shaft and said end of the motor shaft sleeve inserted within said sleeve of said stub shaft having a bore formed in an outer diameter thereof such that the bores of the stub shaft and motor shaft sleeve are aligned and contain therein a fastener for securing the motor shaft sleeve to the stub shaft. 
     
     
         17 . The pump according to  claim 16 , wherein the sleeve of the motor shaft sleeve has multiple longitudinally-extending slots thereby forming a bifurcated sleeve and wherein said bifurcated sleeve of the motor shaft sleeve includes multiple fasteners for compressing bifurcated sections of the motor shaft sleeve into tight engagement with the drive shaft of the motor. 
     
     
         18 . A method of interconnecting a drive shaft of a motor to an impeller of a pump, comprising the steps of:
 selecting a motor shaft sleeve from a set of motor shaft sleeves in which motor shaft sleeves having different inner diameters are provided such that a motor shaft sleeve having an inner diameter that is able to receive and closely matches an outer diameter of the drive shaft of the motor is selected;   inserting an end of the motor shaft sleeve within a cavity of a sleeve of a stub shaft that is secured to the impeller of the pump within a sealed volute chamber;   securing the motor shaft sleeve to the stub shaft; and   securing an opposite end of the motor shaft sleeve to the drive shaft of the motor.   
     
     
         19 . The method according to  claim 18 , wherein said step of inserting the end of the motor shaft sleeve within the cavity of the sleeve of the stub shaft includes positioning a feather key in a keyway formed in an outer diameter of the end of the motor shaft sleeve to be inserted within the stub shaft and aligning the keyway of the motor shaft sleeve with a keyway formed in an inner diameter of the sleeve of the stub shaft such that the feather key is contained within the keyways and prevents relative rotation between the stub shaft and the motor shaft sleeve, and wherein said step of securing the motor shaft sleeve to the stub shaft includes securing a fastener in a bore extending radially through the sleeve of the stub shaft and a bore formed in an outer diameter of the end of the motor shaft sleeve. 
     
     
         20 . The method according to  claim 19 , wherein the sleeve of the motor shaft sleeve has multiple longitudinally-extending slots thereby forming a bifurcated sleeve, and wherein said step of securing an opposite end of the motor shaft sleeve to the drive shaft of the motor includes tightening at least one fastener to compress bifurcated sections of the motor shaft sleeve into tight engagement with the drive shaft of the motor.