FLUID COOLING TECHNIQUE FOR HIGH GVF PUMPING

Description

BACKGROUND

Downhole or surface systems that process fluids with a lower density tend to incur higher fluid temperatures as the fluid is pressurized. In oil and gas production pumping operations, fluids with different densities and Gas Volume Fractions (GVF) are pressurized as they are lifted to surface tanks or production lines for further processing. The GVF is the ratio of gas volumetric flow rate to the total volumetric flow rate of all fluids, at a specific temperature and pressure. Due to the increased pressure in the high GVF flows, the internal temperature of components that interact with the high GVF flow increases as well. These higher component temperatures can eventually lead to equipment failure and incurring expenses in remedial operations. Thus, it is desirable to control and reduce the temperature of a high GVF fluid within a pumping assembly in order to prevent premature wear and component failure.

SUMMARY

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

In one aspect, embodiments disclosed herein relate to a multi-stage pumping assembly that includes a pump housing, a shaft, a motor, a bearing, a pump stage, and an insert. The pump housing includes a fluid inlet that transports fluid into the pump housing and a fluid outlet that transports the fluid out of the pump housing. The shaft primarily extends in an axial direction through the pump housing and is rotated by the motor within the pump housing. The bearing is disposed between the shaft and the pump housing and mechanically decouples the rotation of the shaft from the pump housing. The pump stage surrounds the shaft and includes an impeller and a diffuser that impart a force upon the fluid. The insert also surrounds the shaft and includes an orifice that the fluid is transported through within the pump housing. The orifice has a varying diameter in the axial direction where a first axial end of the orifice has a different diameter than a second axial end of the orifice.

Embodiments described herein further relate to a method for reducing a temperature of a fluid. The method includes transporting the fluid through a fluid inlet into a pump housing and rotating, with a motor that is fixed to the pump housing, a shaft that extends in an axial direction through the pump housing. The method further includes imparting a force on the fluid with a pump stage, including an impeller and receiver that surrounds the shaft and transports the fluid through the pump housing. The fluid is then transported through an orifice of an insert that surrounds the shaft and through a fluid outlet out of the pump housing. In addition, the orifice has a varying diameter in the axial direction such that a first axial end of the orifice has a different diameter than a second axial end of the orifice. Finally, the rotation of the shaft is mechanically decoupled from the pump housing with a bearing.

Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.

FIG. 1 depicts a multi-stage pumping assembly in accordance with one or more embodiments of the invention.

FIG. 2 depicts a multi-stage pumping assembly in accordance with one or more embodiments of the invention.

FIG. 3 depicts a multi-stage pumping assembly in accordance with one or more embodiments of the invention.

FIG. 4 depicts a multi-stage pumping assembly in accordance with one or more embodiments of the invention.

FIGS. 5A and 5B depict alternate views of an insert in accordance with one or more embodiments of the invention.

FIGS. 6A and 6B depict alternate views of an insert in accordance with one or more embodiments of the invention.

FIGS. 7A and 7B depict alternate views of an insert in accordance with one or more embodiments of the invention.

FIG. 8 depicts a flowchart of a method in accordance with one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure is practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

Throughout the application, ordinal numbers, e.g., first, second, third, etc. is used as an adjective for an element i.e., any noun in the application. The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.

In addition, throughout the application, the terms “upper” and “lower” are used to describe the position of an element. In this respect, the term “upper” denotes an element disposed physically above a corresponding “lower” element, while the term “lower” conversely describes an element disposed physically below a corresponding “upper” element in relation to a pump assembly. Likewise, the term “axial” refers to an orientation substantially parallel to a primary axis of extension of an element, while the term “radial” refers to an orientation orthogonal the primary axis of extension.

While embodiments disclosed herein are described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments may be devised which do not depart from the spirit of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

In general, embodiments of the invention are directed towards an insert that restricts or expands a fluid flow path within a pumping assembly or other fluid transmission equipment. During operation, the mixture enters an inlet of the pumping assembly and flows through pump stages, including an impeller and/or a diffuser, which results in an increased fluid temperature due to the energy imbued in the fluid from the impeller. Once passing by at least one pump stage, fluid is passed through the insert. The insert is passive in nature and does not perform work on the fluid, which causes excess heat to be removed from the fluid as the fluid passes through the insert. Thus, when the fluid flows through the insert, its temperature at the exit of the insert decreases. The same process is repeated as the fluid flows through subsequent pump stages and inserts, until the fluid reaches a fluid outlet. As a result of the inserts, the mixture temperature is relatively cooled by the reduced flow path of the pump.

FIG. 1 depicts one embodiment of a multi-stage pumping assembly 11 in accordance with one or more embodiments of the invention. As shown in FIG. 1, a multi-stage pumping assembly 11 includes a motor 13 that is fixed to a pump housing 15. The motor 13 may be an electrical motor, such as an Alternating Current (AC) motor, a Direct Current (DC) motor, or a combustion reaction powered motor, such as a gasoline or diesel engine. The power source of the motor 13 is not considered to be limiting in this regard, and other forms of power such as hydrogen power, solar power, or wind power may be substituted as the power source for the motor 13 without departing from the nature of the invention.

The motor 13 is rigidly fixed to a shaft 17 that extends through the entirety of the pump housing 15 in an axial direction. When power is supplied to the motor 13, the motor 13 rotates the shaft 17 within the pump housing 15. To facilitate the rotation of the shaft 17, the pump housing 15 is equipped with a base shaft bearing 19 and a head shaft bearing 21. The base shaft bearing 19 and the head shaft bearing 21 may be embodied as a roller bearing, a ball bearing, a needle bearing, or equivalent bearings as is commonly known in the art. The base shaft bearing 19 and the head shaft bearing 21 serve to decouple the rotational motion of the shaft 17 from the pump housing 15, while also retaining the shaft 17 in a radial direction relative to the multi-stage pumping assembly 11. Either of the base shaft bearing 19 or the head shaft bearing 21 may be considered a first bearing or a second bearing without departing from the nature of this specification. The base shaft bearing 19 and the head shaft bearing 21 are disposed in and rigidly fixed to a base shaft bearing holder 33 and a head shaft bearing holder 35. The base shaft bearing holder 33 and the head shaft bearing holder 35 are cutouts of the pump housing 15 that retain the bearings in an axial and radial direction, respectively. A thrust handling unit (not shown), which may be, for example, a telescopic thrust handling unit or a rotary thrust handling unit, may also be installed between the motor 13 and the multi-stage pumping assembly 11 without departing from the nature of the invention.

During operation, fluid enters through a fluid inlet 25 of the pump housing 15, which is a borehole or similar orifice disposed in the pump housing 15 to receive fluid from an external source, such as a reservoir or fluid tank (not shown). After passing through the pump housing 15, fluid exits the multi-stage pumping assembly 11 by passing through a fluid outlet 37 to an external environment. For example, fluid that is disposed in a fluid reservoir within a gas well enters the multi-stage pumping assembly 11 through the fluid inlet 25, and exits the multi-stage pumping assembly 11 through the fluid outlet 37 at a high velocity and/or pressure, which lifts the fluid out of the well to a storage container located at the surface of the earth. Alternatively, if the pumping system is at surface, the fluid may flow into a storage tank or processing facility.

As noted above, the fluid passing through the pump housing 15 has a high Gas Volume Fraction (GVF), and may include gases and liquids such as, but not limited to, crude oil, water, steam, hydrogen, natural gas, methane (and similar hydrocarbons), and/or hydrogen sulfide, for example. As used herein, the term fluid may refer to a mixture of gases and liquids, or refer solely to gas or liquid without departing from the nature of the specification. The surface coating process aids in reducing corrosion from the high GVF fluid, which reduces maintenance costs due to premature rusting, pitting, or other forms of abrasive and erosive wear.

Once fluid has passed from the fluid inlet 25 into the pump housing 15, the fluid passes through a plurality of pump stages 23. As the multi-stage pumping assembly 11 includes multiple pump stages 23, the multi-stage pumping assembly 11 functions as a multi-stage pumping assembly. Alternatively, although not depicted, embodiments of the invention may be utilized in a single stage pump assembly that includes a single pump stage 23. Each pump stage 23 of the multi-stage pumping assembly 11 includes an impeller 27 and a diffuser 29. The impeller 27 is rigidly fixed with a collar, a set screw, a brazing or welding procedure, or equivalent process to the shaft 17, while the diffuser 29 is not fixed to the shaft 17. Any of the pump stages 23 may be considered to be a first, second, or third pump stage 23 without departing from the nature of this specification. The impeller 27 serves to increase the velocity and/or pressure of the fluid by transferring rotational force from the shaft 17 to the fluid. To do such, the impeller 27 includes a series of blades or vanes that strike the fluid and imparts a force to the fluid. Similarly, the diffuser 29 reduces the velocity of the fluid after leaving the impeller 27 using a plurality of vanes, which results in an increased pressure of the fluid. As shown in FIG. 1, the diffuser 29 is positioned adjacent to impeller 27 such that fluid passes directly from the impeller 27 to the diffuser 29. The impeller 27 and the diffuser 29 may be formed of metal such as cast iron, bronze, zinc, or steel, or an equivalent metal or metal alloy, or a plastic or thermoplastic such as polycarbonate (PC), polyvinyl chloride (PVC), acrylic, polystyrene, nylon, Teflon, or equivalent polymer known to a person of ordinary skill in the art.

After passing through a pump stage 23, the fluid is transferred to an insert 31. The insert 31 may be formed of metal such as cast iron, bronze, zinc, or steel, or an equivalent metal or metal alloy, or a plastic or thermoplastic such as polycarbonate (PC), polyvinyl chloride (PVC), acrylic, polystyrene, nylon, Teflon, or equivalent polymer known to a person of ordinary skill in the art. Additionally, the insert 31 may be formed of a same material as the impeller 27 and the diffuser 29, or a different material. In order to withstand the heat of the fluid, the insert 31 is coated with a surface coating process that covers the exterior of the insert 31. The surface coating process may be, for example, a thermal spraying process, an electrochemical process (i.e., electroplating), a hot-dip galvanizing process, or equivalent. The surface metal coating itself may be embodied as a zinc, aluminum, iron, an alloy comprising the same metals, or equivalent. Additionally, the insert 31 may be formed by a reaming, lathing, drilling, milling, or equivalent process where the insert 31 is carved from a single block of material. Alternatively, the insert 31 may be formed of a casting process or an additive manufacturing process, which allows the insert 31 to be precisely formed to the desired dimensions for a cooling effect within the multi-stage pumping assembly 11.

As shown in FIG. 1, the insert 31 has a trapezoidal cross section, where each non-sloped face (i.e., base) of the insert 31 is flush with a pump stage 23. The smaller of the two bases that form the trapezoid shape abuts and is disposed to face the fluid inlet 25, while the larger of the two bases is disposed to face a fluid outlet 37. The sloped surface that interconnects the two bases of the insert 31 forms an orifice 39 between the insert 31 and the pump housing 15. Due to the fact that the insert 31 has a trapezoidal cross section, the orifice 39 formed by the insert 31 has a varying diameter in the axial direction. That is, the diameter of the insert 31 at the base of the insert 31 nearest the fluid inlet 25 has a relatively large diameter compared to the smaller diameter of the orifice 39 at the base surface of the insert 31 nearest the fluid outlet 37. The base of the trapezoidal shaped insert 31 closest to the fluid inlet 25 of the multi-stage pumping assembly 11 may be referred to herein as an “inlet” side of the insert 31, while the base of the insert 31 disposed closest to the fluid outlet 37 of the multi-stage pumping assembly 11 may be referred to herein as an “outlet” side of the insert 31 without departing from the nature of the invention.

The dimensions of the insert 31 are determined according to the desired cooling effect. That is, the diameter of the inlet side of the insert 31 may be adjusted according to the diameter of an adjacent pump stage 23, such that the insert 31 has a diameter that is the same or smaller as that of the pump stage 23. Similarly, the vertical distance between the outlet side of the insert 31 and the pump housing 15 may vary according to the desired fluid velocity and a required temperature difference. Thus, the outlet side of the insert 31 may have a diameter that is a same or larger diameter than that of a pump stage 23. The length of the insert 31 similarly corresponds to the desired cooling effect as well, where a longer insert 31 will produce a larger cooling effect than a relatively short insert 31. By way of example, the dimension of the orifice 39 in a radial direction may vary from a tenth of an inch to two inches, inclusive. Similarly, an insert may extend in a radial direction from two inches (or less) to ten inches (or more), and extend in an axial direction from two inches (or less) to six inches (or more). The aforementioned measurements are exemplary only, and the insert 31 may vary in size according to the use case thereof without departing from the nature of the invention.

The gradual change in diameter from the inlet side of the insert 31 to the outlet side of the insert 31 restricts fluid flow within the multi-stage pumping assembly 11. This constriction causes the velocity of the fluid to increase as the fluid moves through the multi-stage pumping assembly 11. The increased fluid velocity causes the temperature of the fluid to decrease as excess heat is transferred to the insert 31 and pump housing 15. Such is derived from the fact that the composition of the fluid does not change within the multi-stage pumping assembly 11, and no internal or external work is done on the fluid by the insert 31 itself. Thus, as the fluid is passing through the insert 31, the velocity of the fluid increases from the constriction. As is commonly known in the art, an increase in fluid velocity causes a decrease in temperature and/or pressure, which is derived from the “energy conservation principle.” Thus, the increased fluid velocity due to the constriction of the fluid flow path causes a decrease in fluid pressure and a decrease in temperature that is translated directly into waste heat energy being removed from the fluid.

Additionally, the inner diameter of the insert 31 is matched to the outer diameter of the shaft 17, such that the multi-stage pumping assembly 11 is assembled by sliding the shaft 17 through the one or more inserts 31 or vice-versa. For its part, the insert 31 is rotationally decoupled from the shaft 17, in that the insert 31 is not fixed to the shaft 17 and does not rotate, similar to the diffuser(s) 29. To retain the insert 31 in an axial direction, the insert 31 is sandwiched between two pump stages 23 whose impellers 27 are fixed to the shaft 17 as described above. To retain the inserts 31 in an axial and radial direction, the inserts 31 may be assembled such that the insert 31 abuts against or is fixed to the diffuser 29, which is stationary as described above. To fix the insert 31 to the diffuser 29, the insert 31 may include retention mechanisms such as a shaft and keyhole or locking tabs (not shown) that retain the insert 31 to the diffuser 29. Thus, during pumping operations, the shaft 17 and each impeller 27 of the pump stages 23 will rotate according to power received from the motor 13, while the inserts 31 remain stationary and instead react to motion from the fluid itself.

After passing through the first insert 31, the fluid passes to a second pump stage 23 where the fluid is imbued with additional force, causing an increase in the fluid's velocity. The fluid subsequently flows from a second pump stage 23 to a second insert 31, which offsets the additional fluid temperature increase from the second pump stage 23 to the second insert 31. This continues over any number of pump stage 23 and insert 31 combinations until the fluid reaches the fluid outlet 37. Thus, as fluid is flowing through the multi-stage pumping assembly 11, the temperature of the fluid rises as the fluid passes through a pump stage 23, and is subsequently lowered as the fluid passes through an insert 31. Overall, the successive decreases in temperature facilitated by the plurality of inserts 31 ensure that fluid that exits a multi-stage pumping assembly 11 having the inserts 31 is cooler than fluid that is processed through a multi-stage pumping assembly 11 without one or more inserts 31.

FIG. 2 depicts an alternate embodiment of a multi-stage pumping assembly 11, where inserts 31 are disposed after every second pump stage 23, rather than being positioned between each pump stage 23 as shown in FIG. 1. Due to the excess energy being lost from the fluid by the insert 31, a multi-stage pumping assembly 11 that is equipped with inserts 31 will require more power than a pump without the inserts 31 to produce an equivalent fluid exit pressure out of the fluid outlet 37. Thus, the multi-stage pumping assembly 11 depicted in FIG. 2 has the advantage of requiring less power overall to produce an equivalent fluid pressure compared to FIG. 1. However, the reduced number of inserts 31 of the multi-stage pumping assembly 11 of FIG. 2 has a relatively higher temperature fluid at its fluid outlet 37 than the multi-stage pumping assembly 11 of FIG. 1, while still maintaining a lower overall fluid temperature when compared to a pump without inserts 31. Accordingly, the overall number of inserts 31, as well as their location(s), depends on the economic and thermal constraints of the contemplated use case of the multi-stage pumping assembly 11 itself.

Turning to FIG. 3, FIG. 3 depicts an alternative embodiment of an insert 31 where fluid flows through an orifice 39 that is disposed internal to the multi-stage pumping assembly 11. That is, while the orifice 39 of FIGS. 1 and 2 is disposed between an insert 31 and the pump housing 15 itself, FIG. 3 presents an alternative embodiment of the insert 31 where the orifice 39 runs through the insert 31. To create the orifice 39, the insert 31 depicted in FIG. 3 includes an outer insert piece 41 and an inner insert piece 43, where the orifice 39 is disposed between the outer insert piece 41 and the inner insert piece 43. The outer insert piece 41 has a triangular cross section, while the inner insert piece 43 has a rectangular cross section. The triangular cross section of the outer insert piece 41, when coupled with the rectangular cross section of the inner insert piece 43, forms an orifice 39 with a trapezoidal cross section, similar to the orifice 39 depicted in FIGS. 1 and 2. Similar to FIGS. 1 and 2, the larger base side of the trapezoidal shaped orifice 39 is considered to be the inlet side of the insert 31 and orifice 39, while the smaller base side of the orifice 39 is considered to be an outlet side of the insert 31 and the orifice 39.

To allow the orifice 39 to extend continuously around the perimeter of the outer insert piece 41, the inner insert piece 43 and the outer insert piece 41 are not coupled to each other, but may be formed from the same body of material. While the shaft 17 extends through the inner insert piece 43, the inner insert piece 43 is rotationally decoupled from the shaft 17. The outer insert piece 41 is rigidly fixed to the pump housing 15, using a brazing or welding process, adhesives, or a retention mechanism such as a shaft and keyhole (not shown), for example, and is also stationary. Alternatively, the outer insert piece 41 may be fixed to a diffuser 29 using a similar process or mechanism, in which case the outer insert piece 41 remains stationary with the diffuser 29. Thus, regardless of whether the insert 31 is formed of one piece or multiple pieces, the piece(s) remain stationary in an axial direction during operation of the multi-stage pumping assembly 11. Similar to the embodiments described in FIGS. 1 and 2, the outer insert piece 41 and the inner insert piece 43 may be formed using a lathing, drilling, milling, or equivalent procedure, or formed by a casting process.

As shown in FIG. 3, the insert 31 is disposed after every second pump stage 23, such that the fluid passes over two impellers 27 and two diffusers 29 prior to being cooled by the insert 31. However, the insert 31 may be disposed before or after any number of intermediary pump stages 23, such that two inserts 31 may be separated by a subset of pump stages 23 that includes as many as one, two, or three or more pump stages 23. Additionally, and although not depicted in FIG. 3, the number of pump stages 23 may not be constant for the entirety of the multi-stage pumping assembly 11. That is, a first insert 31 may be separated from a second insert 31 by a single pump stage 23, while the second insert 31 may be separated from a third insert 31 by two or more pump stages 23. The number of intermediary pump stages 23 can, accordingly, include patterns of pump stage 23 placement, or have any suitable distribution of inserts 31 according to the contemplated use case of the multi-stage pumping assembly 11.

In general, the diameter of the inner insert piece 43 is matched to the overall diameter of the pump stage 23, which prevents eddy currents from forming in the fluid flow path due to a mismatch in diameters between the inner insert piece 43 and the pump stage 23. On the other hand, the dimensions of the outer insert piece 41 depend on the required fluid cooling effect. That is, if the outer insert piece 41 has a large outer diameter on its outlet side, then the dimensions of the orifice 39 will be relatively small and the insert 31 will produce a relatively large cooling effect. On the other hand, if the outer insert piece 41 has a shallow slope, then the cooling effect produced by the insert 31 will decrease. Thus, the overall diameter of the outer insert piece 41 may vary according to the use case of the multi-stage pumping assembly 11 and desired cooling effect.

FIG. 4 depicts an alternative embodiment of a multi-stage pumping assembly 11 where the insert 31 is disposed within a pump stage 23. As shown in FIG. 4, each insert 31 is disposed between an impeller 27 and a diffuser 29. In this arrangement, high velocity fluid leaving the impeller 27 is transferred directly to the insert 31, where the fluid is subsequently cooled while passing through the orifice 39. The cooled fluid proceeds to flow directly into the diffuser 29, where the high velocity of the fluid is exchanged for a higher pressure and lower velocity. After leaving the diffuser 29, fluid is passed to the next impeller 27, and to a subsequent insert 31. This process continues until fluid passes through the last diffuser 29 and exits out of the fluid outlet 37.

The embodiment depicted in FIG. 4 has the added benefit of increasing the fluid velocity with the insert 31 directly after an initial force is imbued into the fluid by the impeller 27. Specifically, because the fluid velocity is increased from the insert 31, but decreased by the diffuser 29, fluid disposed in the orifice 39 depicted in FIG. 4 would have a higher fluid velocity than fluid disposed in an orifice 39 of the embodiment of FIGS. 1-3, which receive fluid directly from a diffuser 29. As described above, the inserts 31 may include retention mechanisms (not shown) such as locking tabs, a shaft and keyhole, that retain the inserts 31 to the diffusers 29 or the pump housing 15. Accordingly, multiple different positions of the insert 31 are contemplated to correspond to the varying use cases of a multi-stage pumping assembly 11.

FIGS. 5A and 5B depict a side view and a front view, respectively, of an insert 31 according to one or more embodiments of the invention. As shown in FIG. 5A, the insert 31 is formed similar to the embodiment depicted in FIG. 4, where the insert 31 is formed of an outer insert piece 41 and an inner insert piece 43. The outer insert piece 41 is formed as a triangular shaped cross section that is revolved around a central axis 45 that extends in the axial direction of the multi-stage pumping assembly 11. Thus, the outer insert piece 41 has an inner diameter that decreases in an axial direction from an inlet side of the outer insert piece 41 to an outlet side of the outer insert piece 41 such that the distance between the surface of the outer insert piece 41 and the shaft 17 decreases in the axial direction. On the other hand, the inner insert piece 43 is formed as a metal annulus that surrounds the shaft 17. As noted above, the outer insert piece 41 and the inner insert piece 43 may be formed of metal such as cast iron, bronze, zinc, or steel, or an equivalent metal or metal alloy, or a plastic or thermoplastic such as polycarbonate (PC), polyvinyl chloride (PVC), acrylic, polystyrene, nylon, Teflon, or equivalent polymer known to a person of ordinary skill in the art, and may be made of a single body of material or formed of separate pieces of material.

Collectively, the outer insert piece 41 and the inner insert piece 43 form a conically shaped orifice 39, where the inner insert piece 43 is disposed interior to the orifice 39 and the outer insert piece 41 surrounds the orifice 39. Due to the gradual constriction of the fluid flow path through the orifice 39, the fluid flow velocity increases as fluid moves through the insert 31, which causes a corresponding decrease in operating temperature.

The insert 31 is retained in a radial direction by the pump housing 15 and is locked into an adjacent diffuser 29. Specifically, the outer insert piece 41 is fixed to the pump housing 15, which keeps the inner insert piece 43 and the outer insert piece 41 aligned with each other in an axial direction. As shown in FIG. 5B, the shaft 17 is disposed in a shaft opening 47, which is a bore in the inner insert piece 43 that has a slightly larger diameter than the outer diameter of the shaft 17. The inner insert piece 43 is not fixed to the shaft 17, and is instead rotationally coupled to an adjacent diffuser 29 during operation. The inner insert piece 43 is also retained in a radial direction relative to the diffuser 29. Thus, as shown in the embodiment depicted in FIG. 5B, the inner insert piece 43 is prevented from contacting the outer insert piece 41.

Turning to FIGS. 6A and 6B, FIGS. 6A and 6B depict alternative embodiments of an insert 31 where an orifice 39 is disposed on the interior of the insert 31. As shown in FIG. 6A, the insert 31 includes four orifices 39, which are delimited by equidistant stiffening spines 49. The number of orifices 39 is not limited to four, and an insert 31 may include any number of stiffening spines 49 that are spaced apart so as to form one or more orifices 39. Additionally, any of the orifices 39 may be considered a first orifice, a second orifice, etc. without departing from the nature of the specification. As described above, the insert 31 may be formed by an additive manufacturing process, or by cutting the orifice(s) 39 out of a single block of material that forms the insert 31. The stiffening spines 49 also enable the insert 31 to remain in contact with the pump housing 15 without being fixed thereto, as the inserts 31 of FIGS. 6A and 6B are not coupled to the shaft 17 and remain stationary during operation.

FIGS. 6A and 6B differ in that the stiffening spines 49 of the insert 31 of FIG. 6A are straight and rectangular in nature, while the stiffening spines 49 of FIG. 6B have a hyperbolic shape. The straight edges of the stiffening spines 49 depicted in FIG. 6A provide additional material that strengthens the insert 31 and prevents the stiffening spines 49 from shearing or otherwise failing. The straight edges of the stiffening spines 49 depicted in FIG. 6A are also advantageous in that the additional material acts as an abrasion and corrosion barrier to the central portion of the insert 31. That is, the stiffening spines 49 of FIG. 6A are capable of retaining the structural integrity of the insert 31 even after losing a portion of the stiffening spines 49 to abrasion, corrosion, or pitting.

On the other hand, the insert 31 depicted in FIG. 6B is shaped to provide a better fluid flow than the embodiment depicted in FIG. 6A. Specifically, because the orifices 39 depicted in FIG. 6B are oblong in nature, the insert 31 does not exhibit corners that fluid flows through. The reduced number of corners of the insert 31 of FIG. 6B causes the fluid to flow in a smooth or less disturbed/interrupted fashion compared to FIG. 6A, as eddy currents do not develop in the corner regions caused by the straight stiffening spines 49 of FIG. 6A.

FIGS. 7A and 7B depict a side view and a front view of an insert 31, respectively, according to one or more embodiments of the invention. The insert 31 of FIG. 7A is similar in structure and function to the insert 31 depicted in FIGS. 1 and 2 such that the insert 31 has a trapezoidal cross section in a two dimensional side view as shown in FIG. 7A, and the three dimensional form of a cone when viewed from an isometric perspective (not shown). Thus, as shown in FIG. 7B, the insert 31 is solid with the exception of a shaft opening 47 that is formed as a bore disposed along a central axis 45 of the insert 31. During operation, fluid is forced to move through the pump housing 15 and an orifice 39 that is constricted by the insert 31. That is, fluid is forced away from the shaft 17 and towards the pump housing 15 as fluid moves from an inlet side of the multi-stage pumping assembly 11 to an outlet side of the multi-stage pumping assembly 11. The abutment of the fluid against the pump housing 15 facilitates heat transfer from the high GVF fluid to the pump housing 15, which dissipates to an external environment of the multi-stage pumping assembly 11. Thus, overall, the insert 31 depicted in FIGS. 7A and 7B has a better fluid heat dissipation than the heat dissipation provided by the inserts 31 depicted in FIGS. 5B, 6A, and 6B, where heat must transfer through an outer insert piece 41 of the insert 31 in order to exit the pump housing 15.

FIG. 8 depicts a method for reducing the temperature of a fluid flowing through a pump. While the various flowchart blocks in FIG. 8 are presented and described sequentially, one of ordinary skill in the art will appreciate that some or all of the blocks may be executed in different orders, may be combined or omitted, and some or all of the blocks may be executed in parallel. Furthermore, the blocks may be performed actively or passively.

The method of FIG. 8 initiates with step 810, where fluid is transported through a fluid inlet 25 into a pump housing 15 of a multi-stage pumping assembly 11. As discussed above, the fluid is a high GVF fluid that contains a gas portion and a liquid portion. The high GVF fluid may have a homogenous mixture of gas and liquid, where fluid is entirely composed of hydrogen, methane, or any other single element or compound. Alternatively, the high GVF fluid may be a heterogeneous mixture such as liquid water mixed with gaseous oxygen. The high GVF fluid may be openly stored in a reservoir, for example, or securely kept in a storage tank. Regardless of how the high GVF fluid is stored, the fluid is transported into the pump housing 15 through a fluid inlet 25, which is a quick connect, coupler, or equivalent structure that passes fluid from an external environment of the multi-stage pumping assembly 11 into the pump housing 15 of the multi-stage pumping assembly 11.

In step 820, a shaft 17 of the multi-stage pumping assembly 11 is rotated. The shaft 17 primarily extends in an axial direction through the pump housing 15 and is rotated by a motor 13. The motor 13 may be powered by electric power received from an outlet or derived from wind or solar energy, or powered by a combustion reaction such as gasoline or diesel combustion. The motor 13 is mechanically fixed to the pump housing 15 with bolts and nuts, screws, adhesives, or a procedure such as brazing or welding. The rotation of the shaft 17 is mechanically decoupled from the diffusers 29 of the multi-stage pumping assembly 11 and the pump housing 15 through the use of a base shaft bearing 19 and a head shaft bearing 21, which are disposed at axial ends of the pump housing 15. During operation, the interiors of the base shaft bearing 19 and the head shaft bearing 21 rotate with the shaft 17, while the exterior surfaces of the base shaft bearing 19 and the head shaft bearing 21 remain stationary. Thus, the shaft 17 is able to rotate within the pump housing 15 with the assistance of the motor 13, the base shaft bearing 19, and the head shaft bearing 21.

In step 830, a force is imparted on the fluid by a pump stage 23 that is disposed in the pump housing 15. Specifically, the pump stage 23 is formed by an impeller 27 and a diffuser 29. The impeller 27 surrounds and is fixed to the shaft 17, while the diffuser 29 surrounds the shaft 17 but is not fixed thereto. Thus, when the shaft 17 rotates from the motor 13, the impeller 27 of the pump stage 23 rotates therewith. The rotation of the impeller 27 of the pump stage 23 causes vanes of the impeller 27 to strike the fluid, and converts the rotational motion of the impeller 27 into axial motion of the fluid through the pump housing 15. After passing through the impeller 27, the fluid passes over a diffuser 29 that reduces the velocity of the fluid in exchange for a corresponding fluid pressure increase. The force generated by the pump stage 23 causes the fluid to be transported through the multi-stage pumping assembly 11, and increases the overall amount of energy stored in the fluid. After passing through a pump stage 23, the fluid is forced through an orifice 39 of an insert 31 in step 840.

In step 840, the fluid is forced by the pump stage 23 through an insert 31 that has an orifice 39. The orifice 39 has a diameter that shrinks in the axial direction, such that the fluid flow path is constricted as fluid flows through the multi-stage pumping assembly 11. This constriction increases the velocity of the fluid, as the fluid is required to flow through the constricted area. The increased fluid velocity causes a corresponding reduction in fluid temperature, as fluid is dissipated to the pump housing 15 and the insert 31.

In step 850, the fluid is transported through a fluid outlet 37 disposed at the axial end of the multi-stage pumping assembly 11. As the fluid has now been cooled by one or more inserts 31, the fluid exiting the fluid outlet 37 has a lower temperature than if the fluid was only acted upon by pump stages 23 within the multi-stage pumping assembly 11. Once the fluid has exited the fluid outlet 37, the fluid may be transmitted to any number of components that operate with the fluid, or the fluid may be passed to a device for further processing. For example, if a multi-stage pumping assembly 11 with inserts 31 is disposed in a wellbore, fluids may be passed from the fluid outlet 37 to dedicated fluid lines that carry the fluid to the surface of the earth.

Accordingly, the aforementioned embodiments of the invention as disclosed relate to devices, methods, and procedures useful for reducing the temperature of a fluid that is transmitted through a pump. Embodiments of the invention are advantageously simple to manufacture, and can be scaled to fit within multiple different sizes of pumps with ease. Furthermore, the number of inserts within a pump can be varied to produce different cooling effects, which presents an easy way to balance an overall pump manufacturing cost and fluid power output from the pump.

Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. For example, the inserts described herein may alternatively be formed from a rigid polymer such as plastic, or any number of similar materials without departing from the nature of the specification. Similarly, the orifices described herein may take numerous different forms, and have different shaped cross sections than those described herein in order to better suit a particular use case. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and further include equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112(f) for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.