Submersible pump

Abstract

A submersible pump includes a housing having first and second compartments. A first flow passage is between the first and second compartments. A drive unit includes a drive shaft connected to a drive end of a pump shaft to drive rotation of the pump shaft, and an electric rotates the drive shaft about the axial direction. The electric motor is arranged inside the first compartment and a hydraulic unit is arranged inside the second compartment, The pump is a seal-less pump without a mechanical seal at the pump shaft and the drive shaft. A dosing unit receives environmental fluid, and a dosing unit provides a dosing fluid from the environmental fluid. The dosing unit is for dosing a presettable amount of the dosing fluid into the first compartment and through a first flow passage into the second compartment.

What is claimed is: 
     
         1 . A submersible pump for conveying a process fluid and configured to be completely immersed in an environmental fluid, the pump comprising:
 a common housing having a first compartment configured to be filled with a dosing fluid, and a second compartment configured to be filled with the process fluid, a first flow passage is disposed between the first compartment and the second compartment;   a pump unit arranged in the common housing;   a drive unit arranged in the common housing,   the common housing comprising an inlet and an outlet for the process fluid, the pump unit comprising a pump shaft extending from a drive end to a non-drive end of the pump shaft and configured to rotate about an axial direction, and a hydraulic unit having at least one impeller fixedly mounted on the pump shaft to convey the process fluid from the inlet to the outlet, the drive unit comprising a drive shaft connected to the drive end of the pump shaft to drive rotation of the pump shaft, and an electric motor configured to rotate the drive shaft about the axial direction, the electric motor arranged inside the first compartment and the hydraulic unit arranged inside the second compartment, and the pump is a seal-less pump without a mechanical seal at the pump shaft and the drive shaft; and   a dosing unit configured to receive the environmental fluid, and provide the dosing fluid from the environmental fluid, and the dosing unit configured to dose a presettable amount of the dosing fluid into the first compartment and through the first flow passage into the second compartment.   
     
     
         2 . The submersible pump in accordance with  claim 1 , wherein the first compartment is arranged adjacent to the second compartment with respect to the axial direction, a first partition wall is disposed between the first compartment and the second compartment, the first flow passage is arranged in the first partition wall, and the pump shaft or the drive shaft extends through the first flow passage. 
     
     
         3 . The submersible pump in accordance with  claim 1 , further comprising a balance drum fixedly connected to the pump shaft between the hydraulic unit and the drive end of the pump shaft, a relief passage is disposed between the balance drum and a stationary part configured to be stationary with respect to the common housing, and a balance line is configured to return the process fluid passing through the relief passage to a low pressure location of the pump unit. 
     
     
         4 . The submersible pump in accordance with  claim 1 , further comprising a first pump bearing unit and a second pump bearing unit to support the pump shaft, and a first motor bearing unit and an second motor bearing unit to support the drive shaft, the first pump bearing unit is arranged between the hydraulic unit and the drive end of the pump shaft, the second pump bearing unit is arranged between the hydraulic unit and the non-drive end of the pump shaft, and the electric motor is arranged between the first motor bearing unit and the second motor bearing unit regarding the axial direction. 
     
     
         5 . The submersible pump in accordance with  claim 4 , wherein the first pump bearing unit, the second pump bearing unit, the first motor bearing unit and the second motor bearing unit are each configured to be lubricated by the process fluid or by the dosing fluid. 
     
     
         6 . The submersible pump in accordance with  claim 4 , wherein the first pump bearing unit and the second pump bearing unit are arranged in the second compartment. 
     
     
         7 . The submersible pump in accordance with  claim 4 , wherein the first motor bearing unit and the second motor bearing unit are arranged in the first compartment. 
     
     
         8 . The submersible pump in accordance with  claim 4 , wherein the first pump bearing unit, the first motor bearing unit and the second motor bearing unit are arranged in the first compartment. 
     
     
         9 . The submersible pump in accordance with  claim 4 , wherein the common housing comprises a third compartment configured to be filled with the dosing fluid, the second compartment is arranged regarding the axial direction between the first compartment and the third compartment, a second flow passage is disposed between the third compartment and the second compartment, the dosing unit is configured to dose an amount of the dosing fluid into the third compartment and through the second flow passage into the second compartment, and the second pump bearing unit is arranged in the third compartment. 
     
     
         10 . The submersible pump in accordance with  claim 9 , wherein a second partition wall is disposed between the third compartment and the second compartment, the second flow passage is arranged in the second partition wall, and the pump shaft extends through the second flow passage. 
     
     
         11 . The submersible pump in accordance with  claim 1 , further comprising an external cooling loop configured to cool and lubricate the drive unit by the dosing fluid, the external cooling loop comprising a heat exchanger to cool the dosing fluid, the heat exchanger arranged outside the common housing and configured to receive the dosing fluid from the first compartment and to recirculate the dosing fluid to the first compartment. 
     
     
         12 . The submersible pump in accordance with  claim 1 , wherein the pump is a vertical pump with the pump shaft extending in the direction of gravity. 
     
     
         13 . The submersible pump in accordance with  claim 12 , wherein the drive unit is arranged on top of the pump unit. 
     
     
         14 . The submersible pump in accordance with  claim 1 , wherein the pump is a subsea pump. 
     
     
         15 . The submersible pump in accordance with  claim 1 , wherein the pump is a water injection pump configured to inject the process fluid. 
     
     
         16 . The submersible pump in accordance with  claim 1 , wherein the pump is a subsea pump configured to be installed on a sea ground. 
     
     
         17 . The submersible pump in accordance with  claim 1 , wherein the process fluid is seawater, and the pump is a water injection pump configured to inject the seawater into a subterranean region.