Vertical suspended centrifugal pump

Abstract

The present invention comprises a vertical suspended centrifugal pump. It is particularly useful to pump process liquids having high purity requirements or for outdoor applications in cold environments. The invention comprises a column that is an outer housing, an internal column that is an inner housing, and a shaft assembly that is partially located inside the inner housing. The outer housing encloses some part of the shaft assembly and at least partially encloses the inner housing. A wet end assembly is positioned to receive liquid through an inlet and to discharge liquid through an outlet. The present invention may be configured to include an internal barrier or buffer liquid reservoir without expensive external piping and reservoirs for pumps having two seals.

We claim: 
     
         1 . A vertical suspended centrifugal pump comprising:
 an outer housing defining an outer housing cavity,   an inner housing defining an inner housing cavity,   a rotatable shaft,   a wet end seal,   the shaft being enclosed partially within the inner housing, the inner housing being at least partially enclosed within the outer housing, the inner housing cavity and the outer housing cavity being isolated from each other, wherein a portion of the shaft communicates with the outer housing cavity below the inner housing cavity and above the wet end seal, and   at least one sensor, the at least one sensor being capable of detecting the presence or absence of a liquid within the outer housing cavity.   
     
     
         2 . A vertical suspended centrifugal pump comprising:
 an outer housing, the outer housing being a column, the column being formed of at least one section, the outer housing having an upper end and a lower end,   a pump casing assembly being formed of at least one section, the pump casing assembly being positioned at the lower end of the outer housing,   a pump lower end cap defining a void that is isolated from the outer housing cavity, the pump lower end cap further defining an inlet and an outlet,   a shaft having an upper end, a lower end, and a vertical axis, the shaft being rotatable about its vertical axis,   an inner housing, the inner housing being a column, the column being formed of at least one section, the inner housing defining an inner housing cavity, the inner housing having an upper end and a lower end,   wherein the outer housing, the inner housing, and the pump casing assembly are mated and define the boundaries of an outer housing cavity,   wherein the inner housing is enclosed within the outer housing cavity,   at least two bearings radially surrounding the shaft, the shaft and the at least two bearings being rotatable with respect to one another, the at least two bearings being within the inner housing,   at least one impeller, the impeller being fixedly attached to the lower end of the shaft and positioned within the void of the pump lower end cap, the impeller being rotatable, and wherein the rotation produces force to drive fluid from the inlet and to the outlet, and   at least one sensor, the at least one sensor being capable of detecting the presence or absence of a liquid within the outer housing cavity.   
     
     
         3 . The vertical suspended centrifugal pump of  claim 2  wherein the outer housing is sealed. 
     
     
         4 . The vertical suspended centrifugal pump of  claim 2  wherein the shaft has a top shaft seal, the top shaft seal being positioned at the upper end of the shaft, an outer seal, the outer seal being positioned at the lower end of the shaft, and a wet end seal, the wet end seal being positioned at the lower end of the shaft assembly and vertically below the outer seal, wherein the top shaft seal, the outer seal, the wet end seal serve to isolate the inner housing cavity, the outer housing cavity, and the void of the pump lower end cap, and wherein at least portion of the shaft that lies between the wet end seal and outer seal, is exposed to the outer housing cavity. 
     
     
         5 . The vertical suspended centrifugal pump of  claim 2  further comprising a mount, defining a mount cavity, and having an upper section and a lower section, wherein the mount is fixedly attached to a base plate and wherein the base plate is fixedly attached to the outer housing. 
     
     
         6 . The vertical suspended centrifugal pump of  claim 2  wherein the outer housing, the inner housing, the pump casing assembly, and the base plate are mated and define the outer housing cavity. 
     
     
         7 . The vertical suspended centrifugal pump of  claim 2  further comprising a motor assembly wherein the motor assembly is attached to the shaft by a coupling means in order to transfer force axially in order to rotate the shaft about its vertical axis. 
     
     
         8 . The vertical suspended centrifugal pump of  claim 2  further comprising a base plate to which the outer housing is fixedly attached. 
     
     
         9 . The vertical suspended centrifugal pump of  claim 2  further comprising a discharge pipe having a discharge pipe inlet, the discharge pipe inlet being connected to the outlet of the pump lower end cap, and a discharge port for pumped liquid to exit. 
     
     
         10 . A vertical suspended centrifugal pump comprising:
 an outer housing, the outer housing being a column, the column being formed of at least one section, the outer housing having an upper end and a lower end,   a pump casing assembly being formed of at least one section, the pump casing assembly being positioned at the lower end of the outer housing,   a pump lower end cap defining a void that is isolated from the outer housing cavity, the pump lower end cap further defining an inlet and an outlet,   a shaft having an upper end, a lower end, and a vertical axis, the shaft being rotatable about its vertical axis,   an inner housing, the inner housing being a column, the column being formed of at least one section, the inner housing defining an inner housing cavity, the inner housing having an upper end and a lower end, wherein the shaft is at least partially enclosed within the inner housing,   wherein the outer housing, the inner housing, and the pump casing assembly are mated and define the boundaries of an outer housing cavity,   wherein the inner housing is partially enclosed within the outer housing cavity and the outer housing is fixedly attached to the inner housing,   at least two bearings radially surrounding the shaft, the shaft and the at least two bearings being rotatable with respect to one another, the at least two bearings being within the inner housing,   at least one impeller, the impeller being fixedly attached to the lower end of the shaft and positioned within the void of the lower end cap, the impeller being rotatable, and wherein the rotation produces force to drive fluid from the inlet to the outlet,   a top shaft seal, the top shaft seal being positioned at the upper end of the shaft, an outer seal, the outer seal being positioned at the lower end of the shaft, and a wet end seal, the wet end seal being positioned at the lower end of the shaft assembly and vertically below the outer seal, wherein the top shaft seal, the outer seal, and the wet end seal serve to isolate the voids of the inner housing cavity, the outer housing cavity, and the void of the end cap, wherein at least portion of the shaft that lies between the wet end seal and outer seal, is exposed to the outer housing cavity,   and   at least one sensor, the at least one sensor being capable of detecting the presence or absence of a liquid within the outer housing cavity.   
     
     
         11 . The vertical suspended centrifugal pump of  claim 10  further comprising a base plate to which the inner housing is fixedly attached. 
     
     
         12 . The vertical suspended centrifugal pump of  claim 10  further comprising a mount, defining a mount cavity, and having an upper section and a lower section, wherein the mount is fixedly attached to a base plate and wherein the base plate is fixedly attached-to the inner housing. 
     
     
         13 . The vertical suspended centrifugal pump of  claim 10  further comprising a motor assembly wherein the motor assembly is attached to the shaft by a coupling means in order to transfer force axially to rotate the shaft about its vertical axis. 
     
     
         14 . The vertical suspended centrifugal pump of  claim 10  further comprising a discharge pipe having an inlet, the inlet connected to the outlet of the pump lower end cap, and a discharge port for pumped liquid to exit. 
     
     
         15 . A vertical suspended centrifugal pump comprising:
 an outer housing, the outer housing being a column, the column being formed of at least one section, the outer housing having an upper end and a lower end,   a pump casing assembly being formed of at least one section, the pump casing assembly being positioned at the lower end of the outer housing,   a pump lower end cap defining a void that is isolated from the outer housing cavity, the pump lower end cap further defining an inlet and an outlet,   a shaft having an upper end, a lower end, and a vertical axis, the shaft being rotatable about its vertical axis,   an inner housing, the inner housing being a column, the column being formed of at least one section, the inner housing defining an inner housing cavity, the inner housing having an upper end and a lower end,   wherein the outer housing, the inner housing, and the pump casing assembly are mated and define the boundaries of an outer housing cavity,   wherein the inner housing is at least partially is enclosed within the outer housing cavity,   at least two bearings radially surrounding the shaft, the shaft and the at least two bearings being rotatable with respect to one another, the at least two bearings being within the inner housing,   at least one impeller, the impeller being fixedly attached to the lower end of the shaft and positioned within the void of the pump lower end cap, the impeller being rotatable, and wherein the rotation produces force to drive fluid from the inlet to the outlet,   a top shaft seal, the top shaft seal being positioned at the upper end of the shaft, an outer seal, the outer seal being positioned at the lower end of the shaft, and a wet end seal, the wet end seal being positioned at the lower end of the shaft assembly and vertically below the outer seal, wherein the top shaft seal, the outer seal, and the wet end seal serve to isolate the voids of the inner housing cavity, the outer housing cavity, and the void of the end cap, wherein at least portion of the shaft that lies between the wet end seal and outer seal, is exposed to the outer housing cavity, and   a desired liquid, wherein the desired liquid at least partially fills the outer housing cavity and serves as an internal barrier in order to provide a barrier or buffer liquid, and the outer housing cavity is a liquid reservoir.   
     
     
         16 . The vertical suspended centrifugal pump of  claim 15  wherein the outer housing cavity further comprises at least one liquid port to facilitate the addition, removal, or circulation of the desired liquid. 
     
     
         17 . The vertical suspended centrifugal pump of  claim 15  further comprising at least one sensor to monitor the desired liquid. 
     
     
         18 . The vertical suspended centrifugal pump of  claim 15  wherein the desired liquid is circulated by an internal or external circulation device. 
     
     
         19 . The vertical suspended centrifugal pump of  claim 15  wherein the outer housing cavity is pressurized in order to provide a seal barrier liquid between the wet end seal and the outer seal. 
     
     
         20 . The vertical suspended centrifugal pump of  claim 15  wherein the outer housing cavity is not pressurized. 
     
     
         21 . The vertical suspended centrifugal pump of  claim 15  further comprising a base plate on which the outer housing is fixedly attached. 
     
     
         22 . The vertical suspended centrifugal pump of  claim 15  further comprising a mount, defining a mount cavity, and having an upper section and a lower section, wherein the mount is fixedly attached to a base plate and wherein the base plate is fixedly attached-to the outer housing. 
     
     
         23 . The vertical suspended centrifugal pump of  claim 15  further comprising a motor assembly wherein the motor assembly is attached to the shaft by a coupling means in order to transfer force axially in order to rotate the shaft about its vertical axis. 
     
     
         24 . The vertical suspended centrifugal pump of  claim 15  further comprising a discharge pipe having an inlet, the inlet connected to the outlet of the pump lower end cap and a discharge port for pumped liquid to exit.