Patent Application
20150104337
This invention relates generally to the field of industrial pumping systems, and more particularly to pump systems used in high-pressure applications.
High pressure pumping systems typically include a pump assembly that is driven by an electric motor. In many designs, the pump assembly is configured as a multi-stage centrifugal pump that includes a number of impellers and diffuses stacked within a tubular housing. When energized, the motor rotates a shaft that is directly or indirectly connected to the impellers and other moving parts within the pump assembly. The rotation of the impellers imparts kinetic energy to the pumped fluid, a portion of which is converted to pressure-head as the fluid passes through the diffusers.
As shown in the PRIOR ART drawing of
Like other prior art designs, the housing 14 is connected to the head 16 and base 18 with a threaded engagement. Significantly, the engagement is created through the use of threads on the inner diameter (“ID”) of the housing 14 with the threads on the outer diameter (“OD”) of the head 16 and base 18. In this configuration, the head 16 and base 18 can be made to be flush with outer diameter of the housing 14. To contain the pumped fluid, o-ring seals 20 have been used in positions external to the threaded connections between the housing 14 and the head 16 and base 18.
While generally effective for lower-pressure applications, the prior art approach for connecting the pump housing to the head and base can be unsatisfactory in high-pressure installations. As the pressure of the fluid within the housing 14 increases, the housing 14 may expand, thereby decreasing the extent of engagement between housing 14 and the head 16 and base 18. If the threaded connections between the housing 14 and the head 16 and base 18 are compromised, the pump assembly 10 may operate at decreased efficiency or fail entirely and allow the head 16 and base 18 to separate from the housing 14. Accordingly, there is a need for an improved pump design that provides for increased resistance to failure at elevated working pressures.
In preferred embodiments, the present invention includes a pump assembly for use within a high pressure pumping system. In a first preferred embodiment, the pump assembly includes a housing, a head and a base. The housing contains at least one centrifugal pump stage. The head and base are attached to the housing with corresponding internal threaded connections. The head and base are further connected to the housing with corresponding external flanged connections. The external flanged connections provide redundant connections that reduce the risk of failure between the housing and the head and base.
In a second preferred embodiment, the invention includes a modular pump assembly that includes a first pump module connected to a second pump module. The first pump module includes a first housing that has a first pair of external flanges located at opposing ends of the first housing. The first pump module further includes a head enclosed within the first housing and a base enclosed within the first housing. Similarly, the second pump module includes a second housing that has a second pair of external flanges located at opposing ends of the second housing. The second pump module includes a head enclosed within the second housing and a base enclosed within the second housing. The second pump module is connected to the first pump module by securing one of the second pair of external flanges is connected to one of the first pair of external flanges.
Thus, the preferred embodiments include pump assemblies that include the use of external flanged connections to back-up the internal threaded connections between the pump head, base and housing.
In accordance with a preferred embodiment of the present invention,
Turning now also to
The pumping system 100 of
In a preferred embodiment, the motor 106 is an electrical motor that receives its power from a surface-based source. Generally, the motor 106 converts electrical energy into mechanical energy, which is transmitted to the pump assembly 108 through one or more shafts (not shown in
Turning to
The head 128 includes exterior head threads 138 that mate with interior head threads 140 on the inside of the housing 124. Similarly, the base 126 includes exterior base threads 142 that mate with interior base threads 144 on the interior of the housing 124. In this way, the head 128 and base 126 can be screwed into the housing 124 to place a compressive load on the diffuser 134 portion of turbomachinery stages 130. The compressive load prevents the diffuser 134 from spinning within the housing 124. The head 128 and base 126 each further include one or more o-ring seals 146 to prevent the passage of fluid through the threaded connection.
The pump assembly 108 further includes a base flange 148 on the base 126, an upstream flange 150 on the housing 124, a downstream flange 152 on the housing 124 and a head flange 154 on the head 128 (collectively, “exterior flanges 148, 150, 152 and 156”). The base flange 148 is preferably slip-fit up to the load shoulder on the exterior surface of the base 126. The upstream flange 150 and downstream flange 152 are preferably shrink-fit then welded to the exterior surface of opposing upstream and downstream ends of the housing 124. Alternatively, the upstream flange 150 and downstream flange 152 can be formed with the housing 124 in unitary construction from a single piece of material. The head flange 154 is preferably welded to the outside of the head 128. Each of the base flange 148, upstream flange 150, downstream flange 152 and head flange 154 are preferably configured as circular flanges that each contain a series of aligned bolt holes 156. Bolts 158 or other suitable fasteners can be placed through the bolts holes 156 to provide back-up retaining force between the base 126 and housing 124 and between the housing 124 and head 128.
In this way, the pump assembly 108 includes both exterior flanged and interior threaded connections between the housing 124 and the each of the base 126 and head 128. The use of interior threaded connections and exterior flanged connections provides a robust pump assembly 108 that is capable of performing at pressures of up to about 10,000 psi.
Turning to
As illustrated in
It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and functions of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. It will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other systems without departing from the scope and spirit of the present invention.
