Multistage centrifugal pump with compression bulkheads

1. A multistage centrifugal pump comprising:

an upstream housing, wherein the upstream housing comprises:

a first end;

a second end; and

an external diameter;

a plurality of turbomachinery stages within the upstream housing, wherein each of the plurality of turbomachinery stages within the upstream housing includes a diffuser and an impeller;

a downstream housing, wherein the downstream housing comprises;

a first end; and

a second end;

a plurality of turbomachinery stages within the downstream housing, wherein each of the plurality of turbomachinery stages within the downstream housing includes a diffuser and an impeller; and

a compression bulkhead connected between the second end of the upstream housing and the first end of the downstream housing, wherein the compression bulkhead is in direct contact with the diffusers within the upstream housing and wherein the compression bulkhead comprises a raised shoulder that limits the extent of engagement between the compression bulkhead and both the upstream housing and the downstream housing.

2. The multistage centrifugal pump of claim 1 , further comprising a pump head connected to the second end of the downstream housing, wherein the pump head applies a compressive force to the diffusers within the downstream housing.

3. The multistage centrifugal pump of claim 1 , wherein the upstream housing and compression bulkhead are configured for threaded engagement.

4. The multistage centrifugal pump of claim 1 , wherein the downstream housing and compression bulkhead are configured for threaded engagement.

5. The multistage centrifugal pump of claim 1 , wherein the compression bulkhead further comprises:

one or more ring seals between the compression bulkhead and the upstream housing; and

one or more ring seals between the compression bulkhead and the downstream housing.

6. The multistage centrifugal pump of claim 1 , wherein the compression bulkhead further comprises a shaft bearing assembly, wherein the shaft bearing assembly comprises:

a central bearing; and

a plurality of flow through passages.

7. An electric submersible pumping system for use in pumping fluids from a wellbore, the electric submersible pumping system comprising:

a motor; and

a multistage centrifugal pump driven by the motor, wherein the multistage centrifugal pump comprises:

a shaft;

an upstream housing, wherein the upstream housing comprises:

a first end;

a second end; and

an external diameter;

a plurality of turbomachinery stages within the upstream housing, wherein each of the plurality of turbomachinery stages within the upstream housing includes a diffuser and an impeller;

a downstream housing, wherein the downstream housing comprises:

a first end;

a second end; and

an external diameter;

a plurality of turbomachinery stages within the downstream housing, wherein each of the plurality of turbomachinery stages within the downstream housing includes a diffuser and an impeller; and

a compression bulkhead connected between the second end of the upstream housing and the first end of the downstream housing, wherein the diffuser within the turbomachinery stage at the first end of the downstream housing is in direct contact with the compression bulkhead and wherein the compression bulkhead comprises a raised shoulder having an external diameter substantially the same as the external diameter of the upstream housing and the external diameter of the downstream housing, and wherein the raised shoulder limits the extent of engagement between the compression bulkhead and both the upstream housing and the downstream housing.

8. The electric submersible pumping system of claim 7 , further comprising a pump head connected to the second end of the downstream housing, wherein the pump head applies a compressive force to the diffusers within the downstream housing.

9. The electric submersible pumping system of claim 7 , wherein the upstream housing and compression bulkhead are configured for threaded engagement and wherein the downstream housing and compression bulkhead are configured for threaded engagement.

10. The electric submersible pumping system of claim 7 , wherein the compression bulkhead further comprises:

one or more ring seals between the compression bulkhead and the upstream housing; and

one or more ring seals between the compression bulkhead and the downstream housing.

11. The electric submersible pumping system of claim 7 , wherein the compression bulkhead further comprises a shaft bearing assembly, wherein the shaft bearing assembly comprises:

a central bearing that supports the shaft; and

a plurality of flow through passages.

12. A method for assembling a multistage centrifugal pump, the method comprising the steps of:

providing an upstream housing that includes a first end and a second end;

providing a downstream housing that includes a first end and a second end;

providing a compression bulkhead that includes an external raised shoulder;

loading a plurality of impellers and diffusers into the upstream housing; and

threading a first end of the compression bulkhead into the second end of the upstream housing such that the compression bulkhead is in direct contact with the plurality of diffusers loaded into the upstream housing, wherein the extent of engagement between the upstream housing and the compression bulkhead is limited by contact between the upstream housing and the external raised shoulder of the compression bulkhead;

threading a first end of the downstream housing onto a second end the compression bulkhead, wherein the extent of engagement between the downstream housing and the compression bulkhead is limited by contact between the downstream housing and the external raised shoulder of the compression bulkhead;

loading a plurality of impellers and diffusers into the downstream housing; and

threading a pump head into the second end of the downstream housing, wherein the step of threading a pump head into the second end of the downstream housing further comprises engaging the pump head within the downstream housing to an extent sufficient to compress the diffusers within the downstream housing to a desired stage compression.

13. The method of claim 12 , further comprising the step of passing a shaft through the impellers in the downstream housing, a shaft bearing assembly in the compression bulkhead and through the impellers in the upstream housing.

14. A method for assembling a multistage centrifugal pump, the method comprising the steps of:

providing a base;

connecting an upstream housing to the base, wherein the upstream housing includes a first end and a second end;

loading a plurality of impellers and diffusers into the upstream housing;

threading a first end of a compression bulkhead into the second end of the upstream housing such that the compression bulkhead applies a compressive force to the plurality of diffusers loaded into the upstream housing;

providing a downstream housing that includes a first end and a second end;

threading a first end of the downstream housing into a second end the compression bulkhead, wherein the downstream housing is separated from the upstream housing by the compression bulkhead;

loading a plurality of impellers and diffusers into the downstream housing;

threading a head into the downstream housing such that the head applies compressive force to the plurality of diffusers loaded into the downstream housing, wherein the plurality of diffusers within the downstream housing are in direct contact with the compression bulkhead; and

passing a shaft through the impellers in the downstream housing, a shaft bearing assembly in the compression bulkhead and through the impellers in the upstream housing.