Modular, multi-stage, integral sealed motor pump with integrally-cooled motors and independently controlled rotor speeds

Abstract

An integral motor pump module directs at least 90% of its rotor discharge over at least 50% of its motor housing surface, thereby cooling the motor with little or no need for a separate flow path. The discharge can flow through an annulus formed between the motor and pump housings, and can extend over substantially all of the sides and rear of the motor housing. The rotor can be fixed to a rotating shaft, or rotate about a fixed shaft, which can be threaded into the motor and/or module housing. A plurality of the modules can be combined into a multi-stage pump, with rotor speeds independently controlled by corresponding variable frequency drives. The motor can be a radial or axial permanent magnet or induction motor. A separate cooling flow can provide additional cooling e.g. when pumping heated process fluids. Embodiments include guide vanes and/or diffusers.

I claim: 
     
         1 . A pump module having an integral motor, the pump module comprising:
 a module housing;   a rotor suspended within the module housing, a front face of the rotor being oriented toward a proximal end of the pump module;   a motor within the module housing, the motor being configured to drive a rotation of the rotor, the motor comprising:
 a motor housing located within the module housing; 
 a stator within the motor housing, the stator comprising an electromagnet directed toward the rotor; and 
 a magnetic device fixed to the rotor and configured to pass in proximity to the electromagnet as the rotor rotates; and 
   a process flow path extending between the module housing and the motor housing over a length of the motor housing, and over at least 20% of a surface of the motor housing, the process flow path being configured such that at least 80% of the process fluid that flows through the pump module from a module inlet to a module outlet is caused by the rotor to flow through the process flow path in direct physical contact with the motor housing.   
     
     
         2 . The pump module of  claim 1 , wherein the rotor is a centrifugal rotor configured to drive the process fluid from a central region thereof to a periphery thereof. 
     
     
         3 . The pump module of  claim 1 , wherein the rotor is suspended by a rotatable shaft, and the rotor is fixed to the shaft. 
     
     
         4 . The pump module of  claim 1 , wherein the rotor is suspended by a fixed shaft, and the rotor is configured to rotate about the shaft. 
     
     
         5 . The pump module of  claim 4 , wherein the rotor is supported on the fixed shaft by a pair of bearings, one of which maintains an axial position of the rotor while the other of which provides radial support of the rotor. 
     
     
         6 . The pump module of  claim 4 , wherein the rotor is supported on the fixed shaft by a single, one-way thrust bearing. 
     
     
         7 . The pump module of  claim 4 , wherein the rotor is supported on the fixed shaft by at least one bearing that is lubricated by the process fluid. 
     
     
         8 . The pump module of  claim 4 , wherein the fixed shaft is fixed to at least one of the motor housing and the module housing. 
     
     
         9 . The pump module of  claim 4 , wherein the fixed shaft is fixed to at least one of the motor housing and the module housing by threaded attachment. 
     
     
         10 . The pump module of  claim 1 , wherein the magnetic device fixed to the rotor is a permanent magnet. 
     
     
         11 . The pump module of  claim 1 , wherein the magnetic device fixed to the rotor is a squirrel cage coil. 
     
     
         12 . The pump module of  claim 1 , wherein the process flow path extends over at least 50% of a surface of the motor housing, and at least 90% of the process fluid that flows through the pump module from the module inlet to the module outlet is caused to flow through the process flow path in direct physical contact with the motor housing. 
     
     
         13 . The pump module of  claim 1 , wherein the process flow path extends over at least 90% of an entire circumference of the motor housing. 
     
     
         14 . The pump module of  claim 1 , wherein the process flow path is the only flow path within the pump module through which the process fluid flows from the module inlet to the module outlet. 
     
     
         15 . The pump module of  claim 1 , further comprising a cooling flow path distinct from the process flow path, the cooling flow path being configured to enable an exchange of heat between the motor housing and a cooling fluid that is lower in temperature than the process fluid flowing in the process flow path. 
     
     
         16 . The pump module of  claim 1 , further comprising guide vanes within the process flow path that are configured to direct flow of the process fluid through the flow path. 
     
     
         17 . The pump module of  claim 1 , wherein the stator is configured to rotate independently of the rotor and in a direction that is opposite to a rotation of direction of the rotor. 
     
     
         18 . The pump module of  claim 1 , further comprising a diffuser that is cooperative with the rotor but is driven by a separate diffuser motor and is thereby able to rotate independently of the rotor. 
     
     
         19 . The pump module of  claim 1 , wherein the motor is a radial motor, whereby the electromagnet is directed toward a radial periphery of the rotor; and the magnetic device is fixed near the radial periphery of the rotor. 
     
     
         20 . The pump module of  claim 1 , wherein the motor is an axial motor, whereby the electromagnet is directed toward a distal side of the rotor; and the magnetic device is fixed to the distal side of the rotor. 
     
     
         21 . A pump comprising a plurality of interconnected pump modules according to  claim 1 . 
     
     
         22 . The pump of  claim 21 , wherein at least two of the motors of the pump modules can be independently controlled so as to cause the corresponding rotors to rotate at different rates. 
     
     
         23 . The pump of  claim 22 , wherein the two, independently controlled pump modules are controlled by separate variable frequency drives. 
     
     
         24 . The pump of  claim 22 , wherein all of the pump modules can be independently controlled. 
     
     
         25 . The pump of  claim 24 , wherein each of the pump modules is controlled by a corresponding variable frequency drive. 
     
     
         26 . The pump of  claim 21 , wherein all of the pump modules are substantially identical to each other. 
     
     
         27 . The pump of  claim 21 , wherein at least two of the rotors of the pump modules are supported by a common shaft. 
     
     
         28 . The pump of  claim 27 , wherein the shaft is a rotatable shaft.