CA2356718A1 - Progressing cavity pump with constant liner thickness - Google Patents
Progressing cavity pump with constant liner thickness Download PDFInfo
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- CA2356718A1 CA2356718A1 CA 2356718 CA2356718A CA2356718A1 CA 2356718 A1 CA2356718 A1 CA 2356718A1 CA 2356718 CA2356718 CA 2356718 CA 2356718 A CA2356718 A CA 2356718A CA 2356718 A1 CA2356718 A1 CA 2356718A1
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Abstract
The progressing cavity pump or motor stator has a generally constant liner thickness, by contrast with prior art pumps having very large liner thickness variations.
The pump or motor stator is made by first coating a helicoidal mandrel with at least one liner material to define a liner of generally constant thickness; then placing the liner-coated mandrel in a housing; then placing a liquid (or liquid containing solids) intermediate material between the liner and the housing, the intermediate material being of a type which can then be solidified; then so solidifying the intermediate material to bond it to the liner and the housing; and then retracting the mandrel, leaving the liner in place bonded to the intermediate material. The liner adheres strongly to the intermediate material, but only weakly to the mandrel, such that out-rotating the mandrel readily separates it from the liner, leaving the liner in place.
The pump or motor stator is made by first coating a helicoidal mandrel with at least one liner material to define a liner of generally constant thickness; then placing the liner-coated mandrel in a housing; then placing a liquid (or liquid containing solids) intermediate material between the liner and the housing, the intermediate material being of a type which can then be solidified; then so solidifying the intermediate material to bond it to the liner and the housing; and then retracting the mandrel, leaving the liner in place bonded to the intermediate material. The liner adheres strongly to the intermediate material, but only weakly to the mandrel, such that out-rotating the mandrel readily separates it from the liner, leaving the liner in place.
Description
This invention relates to the construction of progressing cavity pumps or motors, and in particular provides a progressing cavity pump or motor with a generally constant liner thickness.
Through this specification and in the claims, the expression "generally constant thickness" is intended to be by contrast with those prior art pumps having very large liner thickness differences. It is not intended to indicate that the liner in the invention is truly of constant thickness although this would usually be the case. In fact, in one embodiment, as explained below, there will be variations in thickness to accommodate differential thermal expansion of the pump materials.
Progressing cavity pump and motor stators have been made for many years by injecting an elastomeric liner between a tubular housing and a helicoidal mandrel. This is the primary manufacturing method by all or virtually all of the manufacturers who presently produce stators, including Moyno (USA), Tarby (USA), Roper (USA), Mono (UK), Netzsch (Germany), Artemis (Germany), Kachelle (Germany), Geremia (Brazil), PCM
(France) and many more. This method is illustrated in Figure 1 (prior art), which shows a tubular housing 1, a mandrel 2 and an elastomeric liner 3. The elastomeric liner is injected between the tube and the mandrel to form the helicoidal internal shape of the stator. The elastomeric liner is then cured with heat to vulcanize it.
However, it has been recognized for some years that a constant liner thickness has advantages for certain applications. In some applications it has been advantageous to eliminate the liner entirely, usually due to the limitations imposed by the elastomer.
In order to make constant rubber thickness stators or eliminate the rubber entirely, manufacturers have machined, cast or formed a helicoidal shape into the housing.
Figure 2 (prior art) shows a housing 1 with a helicoidal shaped inner and outer surface formed by casting or forming, as disclosed by in United States patent no.
5,143,343 (Belcher). The elastomeric liner 3 is then injected between the helicoidal shaped housing and the helicoidal shaped mandrel 2. In the case where the helicoidal shape is machined into the housing 1, the external shape of the housing is round rather than helicoidal. After injection, the elastomeric liner is cured with heat to vulcanize it.
Figure 3 (prior art) illustrates a stator manufactured by fitting an intermediate metallic component 4 into a round tubular housing 1. The elastomeric liner 3 is injected between the helicoidal shaped intermediate and the helicoidal shaped mandrel 2. This method has been used by Geremia (Brazil) in their "CTR" and "Metallic Stator" product lines.
Figure 4 (prior art) illustrates a new method of achieving a constant thickness stator, as disclosed in United States patent no. 5,759,019 (Wood). An elastomeric liner 3 is placed over a helicoidal mandrel 2 and a rigid supportive structure 5 is formed by means such as wet filament winding composite material over the liner, or is machined from steel or molded from ceramics. A further supportive structure 6, of a composite material for example, is positioned between the supportive structure 5 and the outer housing 1.
This invention provides an improved method for constructing a progressing cavity pump or motor stator with a generally constant liner thickness. As explained above "generally constant thickness" does not mean constant thickness; it is intended to contrast the invention with those prior art pumps having very large liner thickness variations.
In the invention, the liner thickness would usually be constant since this generally gives optimum pump performance but in special circumstances such as applications with wide temperature differences the liner thickness will be deliberately varied to compensate for differential thermal expansion of the liner and intermediate materials as explained further below.
In the invention, a progressing cavity pump or motor stator having a generally constant liner thickness is made by first coating a helicoidal mandrel with at least one liner material to define a liner of generally constant thickness; then placing the liner-coated mandrel in a housing; then placing a liquid (or liquid containing solids) intermediate material between the liner and the housing, the intermediate material being of a type which can then be solidified; then so solidifying the intermediate material to bond it to the liner and the housing; and then retracting the mandrel, leaving the liner in place bonded to the intermediate material. The liner adheres strongly to the intermediate material, but only weakly to the mandrel, such that out-rotating the mandrel readily separates it from the liner, leaving the liner in place. The mandrel could be made from polished steel and coated with Teflon (trademark), for example, to prevent sticking.
The invention will now be described in detail with reference to the accompanying drawings of the preferred and alternative embodiments, by way of examples only. In the drawings:
Figure 1 (prior art) is a sectional view of a typical progressing cavity pump or motor stator;
Figure 2 (prior art) is a sectional view of a constant thickness stator made by forming, machining or casting a helicoidal shape into the housing;
Figure 3 (prior art) is a sectional view of a constant thickness stator made by forming, machining or casting a helicoidal shape into an intermediate material;
Figure 4 (prior art) is a sectional view of a stator made by filament winding a composite material over a liner-covered mandrel;
Figure 5 is a sectional view of a stator made by introducing an intermediate material between a tubular housing and a liner-covered mandrel which is then solidified;
Figure 6 is a sectional view of a stator made by introducing an intermediate material between a tubular housing and a mandrel covered by a two-layer laminate which is then solidified; and Figure 7 is a sectional view of an alternative embodiment made in the same manner as Figure 5, showing the liner thickness being somewhat less along the sides of the cavity than around the ends of the cavity.
Referring to Figure 5, the stator in the present invention is made as follows.
First a helicoidal mandrel 2 is coated with a one-layer or two-layer liner 3, as explained in greater detail below. The mandrel would usually be machined from steel which is then polished. Usually the mandrel is chrome plated and polished to provide mechanical protection of the surface finish. Prior to coating the mandrel with the liner material, a mold release agent is generally applied to the mandrel to prevent the liner material from sticking to the mandrel. Then an intermediate material 4 is placed between the liner and a tubular housing 1. The intermediate material (a liquid or liquid containing solids) is essentially any material which can be introduced between the liner and the housing and then solidified and bonded to the liner and the housing. The intermediate material can be introduced by pumping, pouring, displacing, extruding or any other method for transferring liquids.
Once the intermediate material 4 is in place, end caps are placed on each end of the tubular housing 1. These end caps support the mandrel 2 and seal around the tubular housing 1 and the mandrel 2 to prevent loss of liner material 3 and intermediate material 4 until the stator is cured.
Drawings of the end caps and mandrel are not provided since these are common items in the manufacture of conventional progressing cavity pump and motor stators and are well known to those skilled in the art of stator manufacturing.
Once the end caps are in place as described above, the intermediate material 4 is solidified and bonded to the tubular housing 1 and the liner material 3. Then the end caps can be removed and the mandrel can be rotated to screw it out of the stator, thus leaving the stator hollow and ready to be fitted with a matching rotor to form a progressing cavity pump:
The embodiments that follow illustrate the material combinations that can be most readily applied to make stators using the principles of the invention.
However, these embodiments are not intended to be limited to the materials mentioned. For example, concrete or cement, would be suitable as intermediate materials since they can be placed in liquid form and then cured to solidify. They might be used in embodiment A
instead of the thermosetting resin intermediate. In this case heat would preferably be applied to the mandrel to cure the liner to the cement or concrete which has previously been solidified.
Several different preferred embodiments are described below, each citing preferred materials and employing the principle of the invention.
Embodiment A
In this embodiment the material of the liner 3 is thermosetting elastomer that is placed over the mandrel 2 by wrapping (as is done in the roll covering industry) or extruding (as is done in the wire and hose industry). The intermediate material 4 is a composite consisting of a thermosetting resin that can be pumped, poured, injected or displaced into the space between the liner and the housing 1. The thermosetting resin contains curative that solidifies the resin by cross-linking. A bond is formed between the resin and the housing 1 and also between the resin and the liner when the resin cures upon heating. Depending on the resin and the elastomer, a bonding agent might be required between the resin 4 and the elastomer 3, or between the resin 4 and the housing 1, to form a strong bond.
A reinforcing material would normally be used with the thermosetting resin to reinforce and strengthen it. Unlike the reinforcement disclosed by Wood in United States patent no. 5,759,019, long fibers suitable for filament winding are not employed since these require placing in particular patterns. Placing fibers in patterns necessitates a filament-winding step, which the invention eliminates. Suitable fine-grained reinforcing materials include sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof because these can be placed by pouring or pumping with the liquid resin. These shapes can be made from materials such as glass, silica, minerals, carbon, graphite, carbon black, sand, metals, polymers, ceramics, clay, talc and other constituents which are well known to the composite materials industry.
The uncured elastomeric liner 3 would be placed over the mandrel 2, the thermosetting resin 4 then placed between the liner 3 and the housing 1. Then the elastomer and thermosetting resin would be heat cured together by heating the housing and/or the mandrel. Alternatively the elastomer could be placed on the mandrel and cured first.
Then the mandrel and cured elastomer would be placed in a tube and a room temperature curing thermosetting resin would be used as the intermediate material.
Thermosetting elastomers are generally used for progressing cavity pump stators due to ease of use and variety of properties. Commonly known thermosetting elastomers are shown in List A.
Another aspect of the present invention is that the intermediate material can be introduced in two steps. The dry reinforcing material can be placed prior to the resin by pouring or vibrating it into place between the mandrel and the housing with the housing held vertically. The resin could then be pumped or displaced into the reinforcing material thus avoiding the need to handle the reinforcing material through the pump. By pumping the resin in from the bottom, air is easily purged from the reinforcing material. Once the liquid resin reaches the top of the housing, pumping can be stopped. After sealing off the ends between the mandrel and the housing, the resin can be solidified to bond it to the reinforcing material, the housing and the liner.
Embodiment B
In this embodiment, the material of the liner 3 is a thermoplastic resin that is placed over the helicoidal mandrel by dipping, spraying, extruding or other methods of placing thermoplastics. A thermoplastic resin might be used instead of a thermosetting elastomer because of its high temperature capability or its chemical resistance. For instance PEEK or other high temperature thermoplastic resin might enable operating a progressing cavity pump or motor to 600F, which is not possible with any known thermosetting elastomer.
In some cases the liner material would be a thermoplastic elastomer selected for its elastomeric properties and ease of application to the mandrel or other criteria. The intermediate material 4 preferably is a thermosetting resin as described in Embodiment A.
Thermoplastic resins are generally referred to as plastics because of their physical properties. They soften when heated and solidify when cooled. Thermoplastic resins in common use are listed in List B.
Thermoplastic elastomers are special thermoplastic materials with elastomeric properties. Thermoplastic elastomers in common use are listed in List C.
Embodiment C
In this embodiment, the liner 3 is made of two layers of liner material 3 and 3', as shown in Figure 6. A thermoplastic resin 3 with flexibility and chemical resistance such as reinforced Teflon or PEEK is placed first on the mandrel by methods as described in Embodiment B. A thermosetting or thermoplastic elastomer 3' is then placed over that by methods as described in embodiment A and B. The intermediate material 4 is then placed as described in Embodiment A. The advantage of this arrangement is that the thermoplastic protects the elastomer from chemical attack and the elastomer provides a soft resilient support for the stiffer thermoplastic resin. The benefit is improved sealing and less requirement for dimensional control of the meshing rotor to stator fit. The two layers may consist of elastomers, thermoplastic resin, or combinations thereof.
Embodiment D
In this embodiment the liner 3 is a hard material such as metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers and refractory metals which ideally can be placed over the helicoidal mandrel by spraying or dipping. To assist retention of the liner or improve its adhesion to the intermediate material, a polymer such as thermosetting resin, thermoplastic resin, or an elastomer might be added to the hard material.
The intermediate material 4 is preferably a thermosetting resin as described in Embodiment A.
The thermosetting resins as described in all of the above embodiments are solidified chemically by heat and/or catalysts. Thermosetting resins in common use are listed in List D. Generally epoxies are the most advantageous due to cost and ease of use.
With the tremendous growth in the variety and types of thermoplastic resins, some are suitable as the intermediate material 4 in the above embodiments rather than a thermosetting resin.
The advantages of making stators by the method described herein include some or all of the following:
1. When making stators by the method illustrated in Figure 2 (prior art), the housing must be made with a helicoidal internal shape. This is expensive and difficult to create, especially on long stators. The present invention uses a round tubular housing.
2. When making stators by the method illustrated in Figure 2 (prior art), the elastomeric liner becomes progressively more difficult to inject as the liner cross section becomes smaller and the length of the pump or motor increases. This can severely limit the stator length or the minimum thickness of the elastomeric liner. The present invention allows the elastomeric liner to be wrapped onto the mandrel or extruded through a cross-feed die (very short extrusion distance) rather than down the long passage between the housing and the mandrel. The liner thickness can be as thin as 1/16 inch if desired. Stator length is limited only by available mandrel and tube lengths.
_g_ 3. When making stators by the method illustrated in Figures 1 or 2 (both prior art), the elastomer must be extruded between the mandrel and the housing, in many cases over a substantial distance. This places limits on the type of elastomer that can be used. Alternatively, the length and the minimum cross section of the liner elastomer must be compromised. The present invention allows much more viscous elastomers to be used since they can be placed by wrapping or by extruding for only relatively short distances through a cross-feed die.
4. When making stators by the method illustrated in Figure 4 (prior art), long continuous fibers must be used. These fibers must be wound over the helicoidal mandrel by a filament winding procedure. The method generally described in Embodiment A eliminates the filament winding. Rather the resin is pumped, poured, injected or displaced into the space between the liner and the housing.
Unlike the method illustrated in Figure 4 (prior art), a tube is required to support the hoop stresses on the composite, but that is a reasonable compromise to eliminate the filament winding and its attendant restrictions to the manufacturing process. Reinforcing materials can be added into the thermosetting resin and the mixture can be placed between the liner and the housing by pumping, pouring, injecting, displacing or other fluid transfer methods, to reduce cost of materials and labor. Also because the process can be done much faster than a filament winding process, the choice of resin and cure systems is not nearly as restricted.
The cost of the fillers can also be reduced relative to long continuous fibers.
5. Embodiment B allows using a thermoplastic resin as the liner, which cannot be done with conventional stator manufacturing methods due to the difficulty in extruding stiff plastics long distances.
6. Embodiment C allows the combination of a chemically resistant thermoplastic resin barrier and a resilient elastomeric support for improved ability to resist swelling or chemical attack of the elastomer while providing a resilient seal to the rotor surface.
_g_ 7. Embodiment D eliminates the elastomer or thermoplastic resin entirely from the inside surface of the stator. This is an economical, more accurate alternative to the machining method presently used to make metallic stators and allows longer stators to be produced. It also allows much harder materials to be used than machinable metals.
Through this specification and in the claims, the expression "generally constant thickness" is intended to be by contrast with those prior art pumps having very large liner thickness differences. It is not intended to indicate that the liner in the invention is truly of constant thickness although this would usually be the case. In fact, in one embodiment, as explained below, there will be variations in thickness to accommodate differential thermal expansion of the pump materials.
Progressing cavity pump and motor stators have been made for many years by injecting an elastomeric liner between a tubular housing and a helicoidal mandrel. This is the primary manufacturing method by all or virtually all of the manufacturers who presently produce stators, including Moyno (USA), Tarby (USA), Roper (USA), Mono (UK), Netzsch (Germany), Artemis (Germany), Kachelle (Germany), Geremia (Brazil), PCM
(France) and many more. This method is illustrated in Figure 1 (prior art), which shows a tubular housing 1, a mandrel 2 and an elastomeric liner 3. The elastomeric liner is injected between the tube and the mandrel to form the helicoidal internal shape of the stator. The elastomeric liner is then cured with heat to vulcanize it.
However, it has been recognized for some years that a constant liner thickness has advantages for certain applications. In some applications it has been advantageous to eliminate the liner entirely, usually due to the limitations imposed by the elastomer.
In order to make constant rubber thickness stators or eliminate the rubber entirely, manufacturers have machined, cast or formed a helicoidal shape into the housing.
Figure 2 (prior art) shows a housing 1 with a helicoidal shaped inner and outer surface formed by casting or forming, as disclosed by in United States patent no.
5,143,343 (Belcher). The elastomeric liner 3 is then injected between the helicoidal shaped housing and the helicoidal shaped mandrel 2. In the case where the helicoidal shape is machined into the housing 1, the external shape of the housing is round rather than helicoidal. After injection, the elastomeric liner is cured with heat to vulcanize it.
Figure 3 (prior art) illustrates a stator manufactured by fitting an intermediate metallic component 4 into a round tubular housing 1. The elastomeric liner 3 is injected between the helicoidal shaped intermediate and the helicoidal shaped mandrel 2. This method has been used by Geremia (Brazil) in their "CTR" and "Metallic Stator" product lines.
Figure 4 (prior art) illustrates a new method of achieving a constant thickness stator, as disclosed in United States patent no. 5,759,019 (Wood). An elastomeric liner 3 is placed over a helicoidal mandrel 2 and a rigid supportive structure 5 is formed by means such as wet filament winding composite material over the liner, or is machined from steel or molded from ceramics. A further supportive structure 6, of a composite material for example, is positioned between the supportive structure 5 and the outer housing 1.
This invention provides an improved method for constructing a progressing cavity pump or motor stator with a generally constant liner thickness. As explained above "generally constant thickness" does not mean constant thickness; it is intended to contrast the invention with those prior art pumps having very large liner thickness variations.
In the invention, the liner thickness would usually be constant since this generally gives optimum pump performance but in special circumstances such as applications with wide temperature differences the liner thickness will be deliberately varied to compensate for differential thermal expansion of the liner and intermediate materials as explained further below.
In the invention, a progressing cavity pump or motor stator having a generally constant liner thickness is made by first coating a helicoidal mandrel with at least one liner material to define a liner of generally constant thickness; then placing the liner-coated mandrel in a housing; then placing a liquid (or liquid containing solids) intermediate material between the liner and the housing, the intermediate material being of a type which can then be solidified; then so solidifying the intermediate material to bond it to the liner and the housing; and then retracting the mandrel, leaving the liner in place bonded to the intermediate material. The liner adheres strongly to the intermediate material, but only weakly to the mandrel, such that out-rotating the mandrel readily separates it from the liner, leaving the liner in place. The mandrel could be made from polished steel and coated with Teflon (trademark), for example, to prevent sticking.
The invention will now be described in detail with reference to the accompanying drawings of the preferred and alternative embodiments, by way of examples only. In the drawings:
Figure 1 (prior art) is a sectional view of a typical progressing cavity pump or motor stator;
Figure 2 (prior art) is a sectional view of a constant thickness stator made by forming, machining or casting a helicoidal shape into the housing;
Figure 3 (prior art) is a sectional view of a constant thickness stator made by forming, machining or casting a helicoidal shape into an intermediate material;
Figure 4 (prior art) is a sectional view of a stator made by filament winding a composite material over a liner-covered mandrel;
Figure 5 is a sectional view of a stator made by introducing an intermediate material between a tubular housing and a liner-covered mandrel which is then solidified;
Figure 6 is a sectional view of a stator made by introducing an intermediate material between a tubular housing and a mandrel covered by a two-layer laminate which is then solidified; and Figure 7 is a sectional view of an alternative embodiment made in the same manner as Figure 5, showing the liner thickness being somewhat less along the sides of the cavity than around the ends of the cavity.
Referring to Figure 5, the stator in the present invention is made as follows.
First a helicoidal mandrel 2 is coated with a one-layer or two-layer liner 3, as explained in greater detail below. The mandrel would usually be machined from steel which is then polished. Usually the mandrel is chrome plated and polished to provide mechanical protection of the surface finish. Prior to coating the mandrel with the liner material, a mold release agent is generally applied to the mandrel to prevent the liner material from sticking to the mandrel. Then an intermediate material 4 is placed between the liner and a tubular housing 1. The intermediate material (a liquid or liquid containing solids) is essentially any material which can be introduced between the liner and the housing and then solidified and bonded to the liner and the housing. The intermediate material can be introduced by pumping, pouring, displacing, extruding or any other method for transferring liquids.
Once the intermediate material 4 is in place, end caps are placed on each end of the tubular housing 1. These end caps support the mandrel 2 and seal around the tubular housing 1 and the mandrel 2 to prevent loss of liner material 3 and intermediate material 4 until the stator is cured.
Drawings of the end caps and mandrel are not provided since these are common items in the manufacture of conventional progressing cavity pump and motor stators and are well known to those skilled in the art of stator manufacturing.
Once the end caps are in place as described above, the intermediate material 4 is solidified and bonded to the tubular housing 1 and the liner material 3. Then the end caps can be removed and the mandrel can be rotated to screw it out of the stator, thus leaving the stator hollow and ready to be fitted with a matching rotor to form a progressing cavity pump:
The embodiments that follow illustrate the material combinations that can be most readily applied to make stators using the principles of the invention.
However, these embodiments are not intended to be limited to the materials mentioned. For example, concrete or cement, would be suitable as intermediate materials since they can be placed in liquid form and then cured to solidify. They might be used in embodiment A
instead of the thermosetting resin intermediate. In this case heat would preferably be applied to the mandrel to cure the liner to the cement or concrete which has previously been solidified.
Several different preferred embodiments are described below, each citing preferred materials and employing the principle of the invention.
Embodiment A
In this embodiment the material of the liner 3 is thermosetting elastomer that is placed over the mandrel 2 by wrapping (as is done in the roll covering industry) or extruding (as is done in the wire and hose industry). The intermediate material 4 is a composite consisting of a thermosetting resin that can be pumped, poured, injected or displaced into the space between the liner and the housing 1. The thermosetting resin contains curative that solidifies the resin by cross-linking. A bond is formed between the resin and the housing 1 and also between the resin and the liner when the resin cures upon heating. Depending on the resin and the elastomer, a bonding agent might be required between the resin 4 and the elastomer 3, or between the resin 4 and the housing 1, to form a strong bond.
A reinforcing material would normally be used with the thermosetting resin to reinforce and strengthen it. Unlike the reinforcement disclosed by Wood in United States patent no. 5,759,019, long fibers suitable for filament winding are not employed since these require placing in particular patterns. Placing fibers in patterns necessitates a filament-winding step, which the invention eliminates. Suitable fine-grained reinforcing materials include sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof because these can be placed by pouring or pumping with the liquid resin. These shapes can be made from materials such as glass, silica, minerals, carbon, graphite, carbon black, sand, metals, polymers, ceramics, clay, talc and other constituents which are well known to the composite materials industry.
The uncured elastomeric liner 3 would be placed over the mandrel 2, the thermosetting resin 4 then placed between the liner 3 and the housing 1. Then the elastomer and thermosetting resin would be heat cured together by heating the housing and/or the mandrel. Alternatively the elastomer could be placed on the mandrel and cured first.
Then the mandrel and cured elastomer would be placed in a tube and a room temperature curing thermosetting resin would be used as the intermediate material.
Thermosetting elastomers are generally used for progressing cavity pump stators due to ease of use and variety of properties. Commonly known thermosetting elastomers are shown in List A.
Another aspect of the present invention is that the intermediate material can be introduced in two steps. The dry reinforcing material can be placed prior to the resin by pouring or vibrating it into place between the mandrel and the housing with the housing held vertically. The resin could then be pumped or displaced into the reinforcing material thus avoiding the need to handle the reinforcing material through the pump. By pumping the resin in from the bottom, air is easily purged from the reinforcing material. Once the liquid resin reaches the top of the housing, pumping can be stopped. After sealing off the ends between the mandrel and the housing, the resin can be solidified to bond it to the reinforcing material, the housing and the liner.
Embodiment B
In this embodiment, the material of the liner 3 is a thermoplastic resin that is placed over the helicoidal mandrel by dipping, spraying, extruding or other methods of placing thermoplastics. A thermoplastic resin might be used instead of a thermosetting elastomer because of its high temperature capability or its chemical resistance. For instance PEEK or other high temperature thermoplastic resin might enable operating a progressing cavity pump or motor to 600F, which is not possible with any known thermosetting elastomer.
In some cases the liner material would be a thermoplastic elastomer selected for its elastomeric properties and ease of application to the mandrel or other criteria. The intermediate material 4 preferably is a thermosetting resin as described in Embodiment A.
Thermoplastic resins are generally referred to as plastics because of their physical properties. They soften when heated and solidify when cooled. Thermoplastic resins in common use are listed in List B.
Thermoplastic elastomers are special thermoplastic materials with elastomeric properties. Thermoplastic elastomers in common use are listed in List C.
Embodiment C
In this embodiment, the liner 3 is made of two layers of liner material 3 and 3', as shown in Figure 6. A thermoplastic resin 3 with flexibility and chemical resistance such as reinforced Teflon or PEEK is placed first on the mandrel by methods as described in Embodiment B. A thermosetting or thermoplastic elastomer 3' is then placed over that by methods as described in embodiment A and B. The intermediate material 4 is then placed as described in Embodiment A. The advantage of this arrangement is that the thermoplastic protects the elastomer from chemical attack and the elastomer provides a soft resilient support for the stiffer thermoplastic resin. The benefit is improved sealing and less requirement for dimensional control of the meshing rotor to stator fit. The two layers may consist of elastomers, thermoplastic resin, or combinations thereof.
Embodiment D
In this embodiment the liner 3 is a hard material such as metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers and refractory metals which ideally can be placed over the helicoidal mandrel by spraying or dipping. To assist retention of the liner or improve its adhesion to the intermediate material, a polymer such as thermosetting resin, thermoplastic resin, or an elastomer might be added to the hard material.
The intermediate material 4 is preferably a thermosetting resin as described in Embodiment A.
The thermosetting resins as described in all of the above embodiments are solidified chemically by heat and/or catalysts. Thermosetting resins in common use are listed in List D. Generally epoxies are the most advantageous due to cost and ease of use.
With the tremendous growth in the variety and types of thermoplastic resins, some are suitable as the intermediate material 4 in the above embodiments rather than a thermosetting resin.
The advantages of making stators by the method described herein include some or all of the following:
1. When making stators by the method illustrated in Figure 2 (prior art), the housing must be made with a helicoidal internal shape. This is expensive and difficult to create, especially on long stators. The present invention uses a round tubular housing.
2. When making stators by the method illustrated in Figure 2 (prior art), the elastomeric liner becomes progressively more difficult to inject as the liner cross section becomes smaller and the length of the pump or motor increases. This can severely limit the stator length or the minimum thickness of the elastomeric liner. The present invention allows the elastomeric liner to be wrapped onto the mandrel or extruded through a cross-feed die (very short extrusion distance) rather than down the long passage between the housing and the mandrel. The liner thickness can be as thin as 1/16 inch if desired. Stator length is limited only by available mandrel and tube lengths.
_g_ 3. When making stators by the method illustrated in Figures 1 or 2 (both prior art), the elastomer must be extruded between the mandrel and the housing, in many cases over a substantial distance. This places limits on the type of elastomer that can be used. Alternatively, the length and the minimum cross section of the liner elastomer must be compromised. The present invention allows much more viscous elastomers to be used since they can be placed by wrapping or by extruding for only relatively short distances through a cross-feed die.
4. When making stators by the method illustrated in Figure 4 (prior art), long continuous fibers must be used. These fibers must be wound over the helicoidal mandrel by a filament winding procedure. The method generally described in Embodiment A eliminates the filament winding. Rather the resin is pumped, poured, injected or displaced into the space between the liner and the housing.
Unlike the method illustrated in Figure 4 (prior art), a tube is required to support the hoop stresses on the composite, but that is a reasonable compromise to eliminate the filament winding and its attendant restrictions to the manufacturing process. Reinforcing materials can be added into the thermosetting resin and the mixture can be placed between the liner and the housing by pumping, pouring, injecting, displacing or other fluid transfer methods, to reduce cost of materials and labor. Also because the process can be done much faster than a filament winding process, the choice of resin and cure systems is not nearly as restricted.
The cost of the fillers can also be reduced relative to long continuous fibers.
5. Embodiment B allows using a thermoplastic resin as the liner, which cannot be done with conventional stator manufacturing methods due to the difficulty in extruding stiff plastics long distances.
6. Embodiment C allows the combination of a chemically resistant thermoplastic resin barrier and a resilient elastomeric support for improved ability to resist swelling or chemical attack of the elastomer while providing a resilient seal to the rotor surface.
_g_ 7. Embodiment D eliminates the elastomer or thermoplastic resin entirely from the inside surface of the stator. This is an economical, more accurate alternative to the machining method presently used to make metallic stators and allows longer stators to be produced. It also allows much harder materials to be used than machinable metals.
8. Using the method described in Embodiment A, the reinforcing material can be placed prior to the resin thus avoiding the need to handle solids through the pump. This method is applicable to pumps made per Embodiments A, B, C or D.
Another aspect of the invention relates to the fact that long pumps or motors can experience high contact forces between the rotor and the stator due to torsional windup of the rotor. This is particularly a problem with slender rotors and long stators that are common in pump stators used on producing oil wells. Conventional stators are not much affected because the rubber is quite thick at the minor diameter. However, pumps that are made with a relatively thin, constant thickness elastomer or thermoplastic or without any resilient materials at all (as in embodiment D) are susceptible to very high contact stresses. These high contact stresses cause premature wear or failure of the stator. In order to reduce the contact stresses caused by rotor wind up, the rotor or stator pitch can be varied. The rotor windup can be represented as a change in pitch. The rotor or stator can then be made with a varying pitch so that when the rotor winds up in normal service, the pitch of the deflected rotor matches the pitch of the stator.
Thus in this aspect of the invention, the pitch of the rotor is slightly reduced from the pitch of the stator, to account for this "windup" such that the pitch of the rotor and stator are matched at the average operating torque.
Yet another aspect of the invention is that the liner thickness can be varied to compensate for differential thermal expansion of the stator materials for applications where the stator must operate over a wide temperature range. Due to the varying thickness of the intermediate material, which generally has an order of magnitude higher coefficient of thermal expansion than a steel housing, the internal cavity becomes distorted when the stator temperature increases. For example, the ideal internal shape of the two lobed stator (used with the single lobed rotor) at any given cross-section is a parallel-sided slot with half-round ends. However, the straight sides of the slot become somewhat concave due to the greater expansion of the thick sections of the intermediate material.
Generally the liner is an elastomer that has a coefficient of thermal expansion several times higher than a composite liner material. By varying the thickness of the elastomeric liner to compensate for the expansion of the intermediate material the ideal shape can be maintained (depending on geometric sizes and coefficients of thermal expansion) as the stator temperature changes. Thus in this aspect of the invention, the liner has a varying thickness such that the shape of the internal cavity remains a slot with straight parallel sides and half-circular ends when the temperature of the stator increases, in the case of a stator with a two lobe helix, for example. The same principle can be applied to stators that use multi-lobe rotors. The thickness of the liner is made less at the minor diameter than at the major diameter to compensate for the thermal expansion of the intermediate material, which is thicker at the minor diameter.
In order that all stator dimensions decrease by the same amount as the stator temperature increases, the dimensions must be varied according to the formula below:
BxC+DxE=BmxC+DmxE
where: B is thickness of intermediate material at any point C is coefficient of thermal expansion of intermediate material D is thickness of liner material at any point E is coefficient of thermal expansion of liner material Bm is thickness of intermediate at the minor diameter of the stator Dm is thickness of liner material at the minor diameter of the stator Depending on the dimensions and the relative rates of thermal expansion of the liner and intermediate, complete compensation may not be possible but reducing the liner thickness as much as practical at the minor diameter and increasing the liner thickness as much as possible at the major diameter and the flanks can still gain some improvement. Using this approach, the liner thickness could be two to three times as thick at the major diameter than at the minor diameter. The same principle can be applied whether the pump uses a single-lobed rotor or a multi-lobed rotor.
In the claims which follow, the expression "substantially liquid" with reference to the intermediate material is intended to cover materials which are either liquids or liquids containing solids and thus having the general properties of a liquid at the processing temperature. Viscosity may vary according to the materials. Obviously, less viscous materials will be easier to put in place, but higher viscosity materials may nevertheless be desirable for other properties.
List A - Thermosettinp Elastomers Acrylate-butadiene rubber (ABR) Broom-isobutene-isoprene Acrylonitrile-butadiene rubber (NBR) Carboxylated Acrylonitrile-butadiene rubber (XNBR) Bromobutyl rubber (BIIR) Butadiene rubber (BR) Butyl para-methylstyrene rubber (BIM) Butyl rubber(IIR, BIIR) Chlorobutyl rubber (CIR) Chlorinated Polyethylene Elastomers (CM, CPE) Chlorosulfonylpolyethylene (CSM) Epichlorohydrins (CO, ECO, ETER) Ethylene/Acrylic Elastomers (EACM) Ethylene octene rubber (EOM) Ethylene-Propylene Copolymers (EPM) Ethylene-Propylene-Diene-methylene Terpolymers (EPDM) Ethylene-vinyl acetate (EVM) Fluoroelastomers (FKM) Hexafluoropropylene-vinylidene fluoride copolymer Vinylidene fluoride copolymer/terpolymer FPM (VF2/HFP, VF2/TFE/P, VF2/PVME/TFE, VF2/HFP/TFE) Fluorosilicone rubbers (VMQ, FVMQ, PVMQ) Haloisobutylene rubber (XIIR) Hydrogenated acrylonitrile-butadiene rubber (HNBR) Isobutylene-Isoprene rubber (IIR) Isobutylene-Paramethylstyrene Elastomers Isoprene-Acrylonitrile Elastomers Isobutene-isoprene rubber (Butyl) (IIR) Natural rubber (NR) Perfluoroelastomer (FFKM) Tetrafluoroethylene perfluoro elastomer Polybutadiene rubber (BR) Polychloroprene (CR) Polychlorotrifluoroethylene (CFM) Polyisobutene (IM) Polyisobutylene Polyisoprene (synthetic natural rubber) (IR) Polyolefin elastomers Polynorbornene Polysulfide rubbers (T) Polyester urethanes (AU) Polyether Urethanes (EU) Polyvinyl acetate Silicone rubber (Q) (VMQ) (FVMQ) (PVMQ) Styrene-butadiene rubber (SBR) Tetrafluorethylene-propylene copolymer (TFP) Acrylic Elastomers (ACM, BA, EA, MEA) Acrylate-butadiene rubber (ABR) Bromo-isobutene-isoprene Acrylonitrile-butadiene rubber (NBR) Carboxylated Acrylonitrile-butadiene rubber (XNBR) Bromobutyl rubber (BIIR) Butadiene rubber (BR) Butyl para-methylstyrene rubber (BIM) Butyl rubber(IIR, BIIR) Chlorobutyl rubber (CIR) Chlorinated Polyethylene Elastomers (CM, CPE) Chlorosulfonylpolyethylene (CSM) Epichlorohydrins (CO, ECO, ETER) Ethylene/Acrylic Elastomers (EACM) Ethylene octene rubber (EOM) Ethylene-Propylene Copolymers (EPM) Ethylene-Propylene-Diene-methylene Terpolymers (EPDM) Ethylene-vinyl acetate (EVM) Fluoroelastomers (FKM) Hexafluoropropylene-vinylidene fluoride copolymer Vinylidene fluoride copolymer/terpolymer FPM (VF2/HFP, VF2/TFE/P, VF2/PVME/TFE, VF2/HFP/TFE) Fluorosilicone rubbers (VMQ, FVMQ, PVMQ) Haloisobutylene rubber (XIIR) Hydrogenated acrylonitrile-butadiene rubber (HNBR) Isobutylene-Isoprene rubber (IIR) Isobutylene-Paramethylstyrene Elastomers Isoprene-Acrylonitrile Elastomers Isobutene-isoprene rubber (Butyl) (IIR) Natural rubber (NR) Perfluoroelastomer (FFKM) Tetrafluoroethylene perfluoro elastomer Polybutadiene rubber (BR) Polychloroprene (CR) Polychlorotrifluoroethylene (CFM) Polyisobutene (IM) Polyisobutylene Polyisoprene (synthetic natural rubber) (IR) Polyolefin elastomers Polynorbornene Polysulfide rubbers (T) Polyester urethanes (AU) Polyether Urethanes (EU) Polyvinyl acetate Silicone rubber (Q) (VMQ) (FVMQ) (PVMQ) Styrene-butadiene rubber (SBR) Tetrafluorethylene-propylene copolymer (TFP) List B - Thermoplastic Resins acetal acrylics Acrylic styrene acrylonitrile (ASA) Acrylonitrile butadiene styrene (ABS) Allylic resins Butyl LM
cellulosics Chlorotrifluoroethylene (CTFE) Depolymerized rubber Ethylene-tetra-fluoro-ethylene (ETFE) Ethylene-chlorotrifluoroethylene (E-CTFE) flouropolymers Fluorinated ethylene propylene (FEP) lonomers nitrites Parylene Perfluoroalkoxy (PFA) Polyamide (PA,nylon) Polyvinyl chloride plastiols Polyallomers polyamide-imide (PAI) polyacrylates Polyaryl ether Polyaryl imides Polyaryl ketone (PAK) Polyaryl sulfone polybutylene Polycarbonate (PC) Polyether-imide (PEI) Polyetherketone (PEK) Polyetheretherketone (PEEK) Polyetherketoneketone (PEKK) Poly(EKEKK) (PEKEKK) polyethylene Polyimides (PI) Polyamide-imide (PAI) polyarylimide Polymethyl pentene Polyolefins polyphenylene oxides polyphenylene sulfides (PPS) Polypropylene (PP) polystyrene Polyphthalamide (PPA) Polytetrafluoroethylene (PTFE) polyurethanes polyvinyl chloride (PVC) silicones styrene acrylonitrile styrene butadiene styrene copolymers Styrene polyester Polyarylene sulfide (PAS) Tetrafluoroethylene (TFE) Polysulfones (PSF) Polyaryl sulfones (PASF) Polyether sulfones (PESV) Polyimide sulfones (PIS02) polyesters polyVinylidene fluoride (PVF) vinyls Vinylidene fluoride (PVF2) List C - Thermoplastic Elastomers Polyester thermoplastic elastomer (COP) Thermoplastic polyester (Y) Copolyether ester thermoplastic elastomer (CPE TPE) Styrenic block copolymers Styrene butadiene styrene (SBS) Styrene ethylene butylene styrene (SEBS) Styrene isoprene styrene (SIS) Thermoplastic block copolymers/styrene-butadiene (YSBR) and styrene-isoprene (YSIR) Thermoplastic elastomeric olefins (TEO) Thermoplastic polyolefins/ethylene-propylene (YEPM) PVC/Nitrile blend (PNBR) EPDM/PP
NR/PP
NR/PE
Alcryn ( Chloro-olefin by Dupont) Geolast (NBR/PP by Advanced Elastomer Systems) Thermoplastic vulcanates PP/EPDM
PP/NBR
PP/Butyl PP/halobutyl PP/NR
PP/EVA/EPDM
Elastomeric polyamides (PEBA) Polyester amide thermoplastic elastomer (PEA TPE) Polyether amide thermoplastic elastomer Thermoplastic polyester urethane(YAU or TPAU) Thermoplastic polyether urethane(YEA or TPEA) Transoctenamer List D - Thermosetting Resins Acrylics esters alkyds allyls polybutadienes melamines silicones ureas polyesters vinyl esters epoxies phenolics cyanates (triazines) bismaleimides Ethylene propylene polysulfides polyimides
Another aspect of the invention relates to the fact that long pumps or motors can experience high contact forces between the rotor and the stator due to torsional windup of the rotor. This is particularly a problem with slender rotors and long stators that are common in pump stators used on producing oil wells. Conventional stators are not much affected because the rubber is quite thick at the minor diameter. However, pumps that are made with a relatively thin, constant thickness elastomer or thermoplastic or without any resilient materials at all (as in embodiment D) are susceptible to very high contact stresses. These high contact stresses cause premature wear or failure of the stator. In order to reduce the contact stresses caused by rotor wind up, the rotor or stator pitch can be varied. The rotor windup can be represented as a change in pitch. The rotor or stator can then be made with a varying pitch so that when the rotor winds up in normal service, the pitch of the deflected rotor matches the pitch of the stator.
Thus in this aspect of the invention, the pitch of the rotor is slightly reduced from the pitch of the stator, to account for this "windup" such that the pitch of the rotor and stator are matched at the average operating torque.
Yet another aspect of the invention is that the liner thickness can be varied to compensate for differential thermal expansion of the stator materials for applications where the stator must operate over a wide temperature range. Due to the varying thickness of the intermediate material, which generally has an order of magnitude higher coefficient of thermal expansion than a steel housing, the internal cavity becomes distorted when the stator temperature increases. For example, the ideal internal shape of the two lobed stator (used with the single lobed rotor) at any given cross-section is a parallel-sided slot with half-round ends. However, the straight sides of the slot become somewhat concave due to the greater expansion of the thick sections of the intermediate material.
Generally the liner is an elastomer that has a coefficient of thermal expansion several times higher than a composite liner material. By varying the thickness of the elastomeric liner to compensate for the expansion of the intermediate material the ideal shape can be maintained (depending on geometric sizes and coefficients of thermal expansion) as the stator temperature changes. Thus in this aspect of the invention, the liner has a varying thickness such that the shape of the internal cavity remains a slot with straight parallel sides and half-circular ends when the temperature of the stator increases, in the case of a stator with a two lobe helix, for example. The same principle can be applied to stators that use multi-lobe rotors. The thickness of the liner is made less at the minor diameter than at the major diameter to compensate for the thermal expansion of the intermediate material, which is thicker at the minor diameter.
In order that all stator dimensions decrease by the same amount as the stator temperature increases, the dimensions must be varied according to the formula below:
BxC+DxE=BmxC+DmxE
where: B is thickness of intermediate material at any point C is coefficient of thermal expansion of intermediate material D is thickness of liner material at any point E is coefficient of thermal expansion of liner material Bm is thickness of intermediate at the minor diameter of the stator Dm is thickness of liner material at the minor diameter of the stator Depending on the dimensions and the relative rates of thermal expansion of the liner and intermediate, complete compensation may not be possible but reducing the liner thickness as much as practical at the minor diameter and increasing the liner thickness as much as possible at the major diameter and the flanks can still gain some improvement. Using this approach, the liner thickness could be two to three times as thick at the major diameter than at the minor diameter. The same principle can be applied whether the pump uses a single-lobed rotor or a multi-lobed rotor.
In the claims which follow, the expression "substantially liquid" with reference to the intermediate material is intended to cover materials which are either liquids or liquids containing solids and thus having the general properties of a liquid at the processing temperature. Viscosity may vary according to the materials. Obviously, less viscous materials will be easier to put in place, but higher viscosity materials may nevertheless be desirable for other properties.
List A - Thermosettinp Elastomers Acrylate-butadiene rubber (ABR) Broom-isobutene-isoprene Acrylonitrile-butadiene rubber (NBR) Carboxylated Acrylonitrile-butadiene rubber (XNBR) Bromobutyl rubber (BIIR) Butadiene rubber (BR) Butyl para-methylstyrene rubber (BIM) Butyl rubber(IIR, BIIR) Chlorobutyl rubber (CIR) Chlorinated Polyethylene Elastomers (CM, CPE) Chlorosulfonylpolyethylene (CSM) Epichlorohydrins (CO, ECO, ETER) Ethylene/Acrylic Elastomers (EACM) Ethylene octene rubber (EOM) Ethylene-Propylene Copolymers (EPM) Ethylene-Propylene-Diene-methylene Terpolymers (EPDM) Ethylene-vinyl acetate (EVM) Fluoroelastomers (FKM) Hexafluoropropylene-vinylidene fluoride copolymer Vinylidene fluoride copolymer/terpolymer FPM (VF2/HFP, VF2/TFE/P, VF2/PVME/TFE, VF2/HFP/TFE) Fluorosilicone rubbers (VMQ, FVMQ, PVMQ) Haloisobutylene rubber (XIIR) Hydrogenated acrylonitrile-butadiene rubber (HNBR) Isobutylene-Isoprene rubber (IIR) Isobutylene-Paramethylstyrene Elastomers Isoprene-Acrylonitrile Elastomers Isobutene-isoprene rubber (Butyl) (IIR) Natural rubber (NR) Perfluoroelastomer (FFKM) Tetrafluoroethylene perfluoro elastomer Polybutadiene rubber (BR) Polychloroprene (CR) Polychlorotrifluoroethylene (CFM) Polyisobutene (IM) Polyisobutylene Polyisoprene (synthetic natural rubber) (IR) Polyolefin elastomers Polynorbornene Polysulfide rubbers (T) Polyester urethanes (AU) Polyether Urethanes (EU) Polyvinyl acetate Silicone rubber (Q) (VMQ) (FVMQ) (PVMQ) Styrene-butadiene rubber (SBR) Tetrafluorethylene-propylene copolymer (TFP) Acrylic Elastomers (ACM, BA, EA, MEA) Acrylate-butadiene rubber (ABR) Bromo-isobutene-isoprene Acrylonitrile-butadiene rubber (NBR) Carboxylated Acrylonitrile-butadiene rubber (XNBR) Bromobutyl rubber (BIIR) Butadiene rubber (BR) Butyl para-methylstyrene rubber (BIM) Butyl rubber(IIR, BIIR) Chlorobutyl rubber (CIR) Chlorinated Polyethylene Elastomers (CM, CPE) Chlorosulfonylpolyethylene (CSM) Epichlorohydrins (CO, ECO, ETER) Ethylene/Acrylic Elastomers (EACM) Ethylene octene rubber (EOM) Ethylene-Propylene Copolymers (EPM) Ethylene-Propylene-Diene-methylene Terpolymers (EPDM) Ethylene-vinyl acetate (EVM) Fluoroelastomers (FKM) Hexafluoropropylene-vinylidene fluoride copolymer Vinylidene fluoride copolymer/terpolymer FPM (VF2/HFP, VF2/TFE/P, VF2/PVME/TFE, VF2/HFP/TFE) Fluorosilicone rubbers (VMQ, FVMQ, PVMQ) Haloisobutylene rubber (XIIR) Hydrogenated acrylonitrile-butadiene rubber (HNBR) Isobutylene-Isoprene rubber (IIR) Isobutylene-Paramethylstyrene Elastomers Isoprene-Acrylonitrile Elastomers Isobutene-isoprene rubber (Butyl) (IIR) Natural rubber (NR) Perfluoroelastomer (FFKM) Tetrafluoroethylene perfluoro elastomer Polybutadiene rubber (BR) Polychloroprene (CR) Polychlorotrifluoroethylene (CFM) Polyisobutene (IM) Polyisobutylene Polyisoprene (synthetic natural rubber) (IR) Polyolefin elastomers Polynorbornene Polysulfide rubbers (T) Polyester urethanes (AU) Polyether Urethanes (EU) Polyvinyl acetate Silicone rubber (Q) (VMQ) (FVMQ) (PVMQ) Styrene-butadiene rubber (SBR) Tetrafluorethylene-propylene copolymer (TFP) List B - Thermoplastic Resins acetal acrylics Acrylic styrene acrylonitrile (ASA) Acrylonitrile butadiene styrene (ABS) Allylic resins Butyl LM
cellulosics Chlorotrifluoroethylene (CTFE) Depolymerized rubber Ethylene-tetra-fluoro-ethylene (ETFE) Ethylene-chlorotrifluoroethylene (E-CTFE) flouropolymers Fluorinated ethylene propylene (FEP) lonomers nitrites Parylene Perfluoroalkoxy (PFA) Polyamide (PA,nylon) Polyvinyl chloride plastiols Polyallomers polyamide-imide (PAI) polyacrylates Polyaryl ether Polyaryl imides Polyaryl ketone (PAK) Polyaryl sulfone polybutylene Polycarbonate (PC) Polyether-imide (PEI) Polyetherketone (PEK) Polyetheretherketone (PEEK) Polyetherketoneketone (PEKK) Poly(EKEKK) (PEKEKK) polyethylene Polyimides (PI) Polyamide-imide (PAI) polyarylimide Polymethyl pentene Polyolefins polyphenylene oxides polyphenylene sulfides (PPS) Polypropylene (PP) polystyrene Polyphthalamide (PPA) Polytetrafluoroethylene (PTFE) polyurethanes polyvinyl chloride (PVC) silicones styrene acrylonitrile styrene butadiene styrene copolymers Styrene polyester Polyarylene sulfide (PAS) Tetrafluoroethylene (TFE) Polysulfones (PSF) Polyaryl sulfones (PASF) Polyether sulfones (PESV) Polyimide sulfones (PIS02) polyesters polyVinylidene fluoride (PVF) vinyls Vinylidene fluoride (PVF2) List C - Thermoplastic Elastomers Polyester thermoplastic elastomer (COP) Thermoplastic polyester (Y) Copolyether ester thermoplastic elastomer (CPE TPE) Styrenic block copolymers Styrene butadiene styrene (SBS) Styrene ethylene butylene styrene (SEBS) Styrene isoprene styrene (SIS) Thermoplastic block copolymers/styrene-butadiene (YSBR) and styrene-isoprene (YSIR) Thermoplastic elastomeric olefins (TEO) Thermoplastic polyolefins/ethylene-propylene (YEPM) PVC/Nitrile blend (PNBR) EPDM/PP
NR/PP
NR/PE
Alcryn ( Chloro-olefin by Dupont) Geolast (NBR/PP by Advanced Elastomer Systems) Thermoplastic vulcanates PP/EPDM
PP/NBR
PP/Butyl PP/halobutyl PP/NR
PP/EVA/EPDM
Elastomeric polyamides (PEBA) Polyester amide thermoplastic elastomer (PEA TPE) Polyether amide thermoplastic elastomer Thermoplastic polyester urethane(YAU or TPAU) Thermoplastic polyether urethane(YEA or TPEA) Transoctenamer List D - Thermosetting Resins Acrylics esters alkyds allyls polybutadienes melamines silicones ureas polyesters vinyl esters epoxies phenolics cyanates (triazines) bismaleimides Ethylene propylene polysulfides polyimides
Claims (57)
1. A method of constructing a progressing cavity pump or motor stator having a liner of generally constant thickness within a housing, comprising the steps of:
a. coating a helicoidal mandrel with at least one liner material to define said liner of generally constant thickness;
b. placing the liner-coated mandrel in the housing;
c. introducing an intermediate material in a substantially liquid state between the liner and the housing;
d. solidifying said intermediate material to bond to said liner and said housing; and e. retracting said mandrel, leaving said liner in place bonded to said intermediate material.
a. coating a helicoidal mandrel with at least one liner material to define said liner of generally constant thickness;
b. placing the liner-coated mandrel in the housing;
c. introducing an intermediate material in a substantially liquid state between the liner and the housing;
d. solidifying said intermediate material to bond to said liner and said housing; and e. retracting said mandrel, leaving said liner in place bonded to said intermediate material.
2. A method as defined in claim 1 wherein said introducing of intermediate material includes introducing by pumping, pouring, displacing, extruding or any other method for transferring liquids.
3. A method as defined in claim 1, said coating a mandrel including coating by spraying, wrapping, dipping, or extruding said liner material on said mandrel.
4. A method as defined in claim 1, said solidifying including solidifying chemically, assisted by heat or catalysts as required.
5. A method as recited in claim 1 or 2, said intermediate material being selected from the group consisting of thermosetting resin, thermoplastic resin, cement, thermosetting resin containing fine grained reinforcing materials, thermoplastic resin containing fine grained reinforcing materials and cement containing fine grained reinforcing materials.
6. A method as recited in claims 5, said fine-grained reinforcing materials being selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof.
7. A method as recited in claim 5, said thermosetting resin being selected from the group consisting of thermosetting resins listed in List D and combinations thereof and said thermoplastic resins being selected from the group consisting of thermoplastic resins listed in List B and combinations thereof.
8. A method as recited in claim 1, said liner material being selected from the group consisting of thermosetting elastomers, thermoplastic elastomers, and thermoplastic resins.
9. A method as recited in claim 8, said thermosetting elastomer being selected from the group consisting of thermosetting elastomers listed in List A and combinations thereof, said thermoplastic elastomers being selected from the group consisting of thermoplastic elastomers listed in List C and combinations thereof, and said thermoplastic resins being selected from the group consisting of thermoplastic resins listed in List B and combinations thereof.
10. A method as recited in claim 3, wherein said liner material is a hard material capable of withstanding wear or abrasion.
11. A method as recited in claim 10, wherein said hard material is selected from the group consisting of metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers, refractory metals and combinations thereof.
12. A method as recited in claims 10 or 11 wherein said hard material is mixed with a polymer selected from the group consisting of thermosetting resin, thermoplastic resin, thermosetting elastomer, thermoplastic elastomer and combinations thereof.
13. A method of constructing a progressing cavity pump or motor stator having a liner of generally constant thickness within a housing, comprising the steps of:
a. coating a helicoidal mandrel with a liner material to define said liner of generally constant thickness, said liner material being a thermosetting elastomer selected from the group consisting of thermosetting elastomers listed in List A and combinations thereof, placing the liner-coated mandrel in the housing;
b. introducing an intermediate material in a substantially liquid state between the liner and the housing, said intermediate material consisting of thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof;
c. solidifying said intermediate material by the application of heat to bond to said liner and said housing and to cure said thermosetting elastomer; and d. retracting said mandrel, leaving said liner in place bonded to said intermediate material.
a. coating a helicoidal mandrel with a liner material to define said liner of generally constant thickness, said liner material being a thermosetting elastomer selected from the group consisting of thermosetting elastomers listed in List A and combinations thereof, placing the liner-coated mandrel in the housing;
b. introducing an intermediate material in a substantially liquid state between the liner and the housing, said intermediate material consisting of thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof;
c. solidifying said intermediate material by the application of heat to bond to said liner and said housing and to cure said thermosetting elastomer; and d. retracting said mandrel, leaving said liner in place bonded to said intermediate material.
14. A method as defined in claim 13 wherein said introducing of intermediate material includes introducing by pumping, pouring, displacing, extruding or any other method for transferring liquids.
15. A method as defined in claim 13 or 14, said coating a mandrel including coating by spraying, wrapping, dipping, or extruding said liner material on said mandrel.
16. A method of constructing a progressing cavity pump or motor stator having a liner of generally constant thickness within a housing, comprising the steps of:
a. coating a helicoidal mandrel with two layers of liner material to define said liner of generally constant thickness, said liner material consisting of a thermoplastic resin selected from the group consisting of thermoplastic resins listed in List B
and combinations thereof with resilience and chemical resistance placed first on the mandrel, and a thermosetting elastomer selected from the group consisting of thermosetting elastomers listed in List A and combinations thereof or thermoplastic elastomer selected from the group consisting of thermoplastic elastomers listed in List C and combinations thereof then placed over that and then placing the liner-coated mandrel in the housing;
b. introducing an intermediate material in a substantially liquid state between the liner and the housing, said intermediate material consisting of thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof;
c. solidifying said intermediate material by the application of heat to bond to said liner and said housing and to cure said thermosetting elastomer; and d. retracting said mandrel, leaving said liner in place bonded to said intermediate material.
a. coating a helicoidal mandrel with two layers of liner material to define said liner of generally constant thickness, said liner material consisting of a thermoplastic resin selected from the group consisting of thermoplastic resins listed in List B
and combinations thereof with resilience and chemical resistance placed first on the mandrel, and a thermosetting elastomer selected from the group consisting of thermosetting elastomers listed in List A and combinations thereof or thermoplastic elastomer selected from the group consisting of thermoplastic elastomers listed in List C and combinations thereof then placed over that and then placing the liner-coated mandrel in the housing;
b. introducing an intermediate material in a substantially liquid state between the liner and the housing, said intermediate material consisting of thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof;
c. solidifying said intermediate material by the application of heat to bond to said liner and said housing and to cure said thermosetting elastomer; and d. retracting said mandrel, leaving said liner in place bonded to said intermediate material.
17. A method as defined in claim 16 wherein said introducing of intermediate material includes introducing by pumping, pouring, displacing, extruding or any other method for transferring liquids.
18. A method as defined in claim 16 or 17, said coating a mandrel including coating by spraying, wrapping, dipping, or extruding said liner material on said mandrel.
19. A method of constructing a progressing cavity pump or motor stator having a liner of generally constant thickness within a housing, comprising the steps of:
a. coating a helicoidal mandrel with a hard material selected from the group consisting of metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers, refractory metals and combinations thereof, said coating being done by spraying a mixture of said hard material in a matrix of thermosetting resin or thermoplastic resin, and;
b. introducing an intermediate material in a substantially liquid state between the liner and the housing, said intermediate material consisting of thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof;
c. solidifying said intermediate material and said matrix material by the application of heat to bond said intermediate material to said liner and said housing; and d. retracting said mandrel, leaving said liner in place bonded to said intermediate material.
a. coating a helicoidal mandrel with a hard material selected from the group consisting of metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers, refractory metals and combinations thereof, said coating being done by spraying a mixture of said hard material in a matrix of thermosetting resin or thermoplastic resin, and;
b. introducing an intermediate material in a substantially liquid state between the liner and the housing, said intermediate material consisting of thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof;
c. solidifying said intermediate material and said matrix material by the application of heat to bond said intermediate material to said liner and said housing; and d. retracting said mandrel, leaving said liner in place bonded to said intermediate material.
20. A method as defined in claim 19 wherein said introducing of intermediate material includes introducing by pumping, pouring, displacing, extruding or any other method for transferring liquids.
21. A method as recited in claim 1, wherein said liner comprises two layers of said liner material, comprising a thermoplastic resin with resilience and chemical resistance placed first on the mandrel, and a thermosetting elastomer or thermoplastic elastomer then placed over that.
22. A method as defined in claim 21, wherein said introducing of intermediate material includes introducing by pumping, pouring, displacing, extruding or any other method for transferring liquids.
23. A method as defined in claim 21, said coating a mandrel including coating by spraying, wrapping, dipping, or extruding said liner material on said mandrel.
24. A method as defined in claim 21, said solidifying including solidifying chemically, assisted by heat or catalysts as required.
25. A method as recited in claim 21 or 22, said intermediate material being selected from the group consisting of thermosetting resin, thermoplastic resin, cement, thermosetting resin containing fine grained reinforcing materials, thermoplastic resin containing fine grained reinforcing materials and cement containing fine grained reinforcing materials.
26. A method as recited in claim 25, said fine-grained reinforcing materials being selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof.
27. A method as recited in claim 25, said thermosetting resin being selected from the group consisting of thermosetting resins listed in List D and combinations thereof and said thermoplastic resins being selected from the group consisting of thermoplastic resins listed in List B and combinations thereof.
28. A method as recited in claim 1 or 3, further comprising varying the thickness of said liner such that said liner thickness is less where the intermediate material is thickest and the liner thickness is more where the intermediate material is thinner, thereby tending to better maintain the geometric shape of the stator cavity when the temperature of the stator increases.
29. A method as defined in claim 1 or 3, said coating step including forming the liner so that the sum of the product of the thickness of the intermediate material at a given point and the coefficient of thermal expansion of the intermediate material and the product the thickness of the liner material at the given point and the coefficient of thermal expansion of the liner material is substantially equal to the sum of product of the thickness of intermediate material at a minor diameter of the stator and the coefficient of thermal expansion of the intermediate material and the product of the coefficient of thermal expansion of the liner material and the thickness of liner material at the minor diameter of the stator.
30. A stator for a progressing cavity pump or motor, comprising:
a liner having a generally constant thickness;
a housing; and an intermediate material between said liner and said housing, said intermediate material being any material which was introduced between the liner and the housing in substantially liquid form and then solidified and bonded to the liner and the housing substantially liquid material which can be introduced between the liner and the housing and then solidified and bonded to the liner and the housing.
a liner having a generally constant thickness;
a housing; and an intermediate material between said liner and said housing, said intermediate material being any material which was introduced between the liner and the housing in substantially liquid form and then solidified and bonded to the liner and the housing substantially liquid material which can be introduced between the liner and the housing and then solidified and bonded to the liner and the housing.
31. A stator for a progressing cavity pump or motor as recited in claim 30, said intermediate material being selected from the group consisting of thermosetting resin, thermoplastic resin, cement, thermosetting resin containing fine grained reinforcing materials, thermoplastic resin containing fine grained reinforcing materials and cement containing fine grained reinforcing materials.
32. A progressing cavity pump or motor as recited in claim 31, said fine-grained reinforcing materials being selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof.
33. A stator for a progressing cavity pump or motor as recited in claim 31 or 32, said thermosetting resin being selected from the group consisting of thermosetting resins listed in List D and combinations thereof and said thermoplastic resins being selected from the group consisting of thermoplastic resins listed in List B and combinations thereof.
34. A stator for a progressing cavity pump or motor as recited in claim 30, wherein said liner comprises two layers of said liner material, comprising a thermoplastic resin selected from the group consisting of thermoplastic resins listed in List B
and combinations thereof with resilience and chemical resistance placed first on the mandrel, and a thermosetting elastomer selected from the group of thermosetting elastomers listed in List A or combinations thereof or thermoplastic elastomer selected from the list of thermoplastic elastomers listed in List C and combinations thereof then placed over that.
and combinations thereof with resilience and chemical resistance placed first on the mandrel, and a thermosetting elastomer selected from the group of thermosetting elastomers listed in List A or combinations thereof or thermoplastic elastomer selected from the list of thermoplastic elastomers listed in List C and combinations thereof then placed over that.
35. A stator for a progressing cavity pump or motor as recited in claim 34, said intermediate material being selected from the group consisting of thermosetting resin, thermoplastic resin, cement, thermosetting resin containing fine grained reinforcing materials, thermoplastic resin containing fine grained reinforcing materials and cement containing fine grained reinforcing materials.
36. A stator for a progressing cavity pump or motor as recited in claim 35, said fine-grained reinforcing materials being selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof.
37. A stator for a progressing cavity pump or motor as recited in claim 35 said thermosetting resin being selected from the group consisting of thermosetting resins listed in List D and combinations thereof and said thermoplastic resins being selected from the group consisting of thermoplastic resins listed in List B and combinations thereof.
38. A stator for a progressing cavity pump or motor as recited in claim 36 said thermosetting resin being selected from the group consisting of thermosetting resins listed in List D and combinations thereof and said thermoplastic resins being selected from the group consisting of thermoplastic resins listed in List B and combinations thereof.
39. A stator for a progressing cavity pump or motor as recited in claim 30, further comprising varying the thickness of said liner such that said liner thickness is less where the intermediate material is thickest and the liner thickness is more where the intermediate material is thinner, thereby tending to better maintain the geometric shape of the stator cavity when the temperature of the stator increases.
40. A progressing cavity pump or motor comprising:
a stator having a helicoidal recess of a predetermined pitch; and a helicoidal rotor engageable with said recess in said stator, said rotor having a pitch slightly less than that of said stator such that torque-induced windup of said rotor during operation is accommodated.
a stator having a helicoidal recess of a predetermined pitch; and a helicoidal rotor engageable with said recess in said stator, said rotor having a pitch slightly less than that of said stator such that torque-induced windup of said rotor during operation is accommodated.
41. A stator for a progressing cavity pump or motor as recited in claim 30, wherein said liner material is a hard material capable of withstanding wear and abrasion.
42. A stator for a progressing cavity pump or motor as recited in claim 30 or wherein said hard material is selected from the group consisting of metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers, refractory metals and combinations thereof.
43. A stator for a progressing cavity pump or motor as recited in claim 42 wherein said hard material is mixed with a polymer selected from the group consisting of thermosetting resin, thermoplastic resin, thermosetting elastomer, thermoplastic elastomer and combinations thereof.
44. A stator for a progressing cavity pump or motor, comprising:
a liner having a generally constant thickness, said liner material being a thermosetting elastomer selected from the group consisting of thermosetting elastomers listed in List A and combinations thereof;
a housing; and an intermediate material between said liner and said housing, said intermediate material consisting of a thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof, which has been solidified and bonded to the liner and the housing.
a liner having a generally constant thickness, said liner material being a thermosetting elastomer selected from the group consisting of thermosetting elastomers listed in List A and combinations thereof;
a housing; and an intermediate material between said liner and said housing, said intermediate material consisting of a thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof, which has been solidified and bonded to the liner and the housing.
45. A stator for a progressing cavity pump or motor, comprising:
a liner having a generally constant thickness, wherein said liner comprises two layers of said liner material, consisting of a thermoplastic resin with resilience and chemical resistance on the inside of the stator and a thermosetting elastomer or thermoplastic elastomer placed next;
a housing; and an intermediate material between said liner and said housing, said intermediate material consisting of a thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof, which has been solidified and bonded to the liner and the housing.
a liner having a generally constant thickness, wherein said liner comprises two layers of said liner material, consisting of a thermoplastic resin with resilience and chemical resistance on the inside of the stator and a thermosetting elastomer or thermoplastic elastomer placed next;
a housing; and an intermediate material between said liner and said housing, said intermediate material consisting of a thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof, which has been solidified and bonded to the liner and the housing.
46. A stator for a progressing cavity pump or motor, comprising:
a liner having a generally constant thickness, said liner material being a hard material capable of withstanding wear or abrasion selected from the group consisting of metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers, refractory metals and combinations thereof wherein said hard material is mixed with a polymer selected from the group consisting of thermosetting resin, thermoplastic resin, thermosetting elastomer, thermoplastic elastomer and combinations thereof;
a housing; and an intermediate material between said liner and said housing, said intermediate material consisting of a thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof, which has been solidified and bonded to the liner and the housing.
a liner having a generally constant thickness, said liner material being a hard material capable of withstanding wear or abrasion selected from the group consisting of metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers, refractory metals and combinations thereof wherein said hard material is mixed with a polymer selected from the group consisting of thermosetting resin, thermoplastic resin, thermosetting elastomer, thermoplastic elastomer and combinations thereof;
a housing; and an intermediate material between said liner and said housing, said intermediate material consisting of a thermosetting epoxy and a fined grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof, which has been solidified and bonded to the liner and the housing.
47. A method of constructing a progressing cavity pump or motor stator having a liner of generally constant thickness within a housing, comprising the steps of:
a. coating a helicoidal mandrel with at least one liner material to define said liner of generally constant thickness;
b. placing the liner-coated mandrel in the housing and standing said housing housing vertical;
c. introducing fine-grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof between the liner and the housing;
d. introducing a liquid material into said fine grained reinforcing material;
e. solidifying said liquid material to bond to said fine-grained reinforcing material, said liner and said housing; and f. retracting said mandrel, leaving said liner in place.
a. coating a helicoidal mandrel with at least one liner material to define said liner of generally constant thickness;
b. placing the liner-coated mandrel in the housing and standing said housing housing vertical;
c. introducing fine-grained reinforcing material selected from the group consisting of sand, glass microspheres, thermoplastic microspheres, discontinuous fibers, whiskers, powders, granular materials, flakes, and combinations thereof between the liner and the housing;
d. introducing a liquid material into said fine grained reinforcing material;
e. solidifying said liquid material to bond to said fine-grained reinforcing material, said liner and said housing; and f. retracting said mandrel, leaving said liner in place.
48. A method as defined in claim 47, said coating a mandrel including coating by spraying, wrapping, dipping, or extruding said liner material on said mandrel.
49. A method as defined in claim 47, said solidifying including solidifying chemically, assisted by heat or catalysts as required.
50. A method as recited in claim 47, said liquid material being selected from the group consisting of thermosetting resin, thermoplastic resin, cement or combinations thereof.
51. A method as recited in claim 50, said thermosetting resin being selected from the group consisting of thermosetting resins listed in List D and combinations thereof and said thermoplastic resins being selected from the group consisting of thermoplastic resins listed in List B and combinations thereof.
52. A method as recited in claim 49, said liner material being selected from the group consisting of thermosetting elastomers, thermoplastic elastomers, and thermoplastic resins.
53. A method as recited in claim 52, said thermosetting elastomer being selected from the group consisting of thermosetting elastomers listed in List A and combinations thereof, said thermoplastic elastomers being selected from the group consisting of thermoplastic elastomers listed in List C and combinations thereof, and said thermoplastic resins being selected from the group consisting of thermoplastic resins listed in List B and combinations thereof.
54. A method as recited in claim 47, wherein said liner material is a hard material capable of withstanding wear or abrasion.
55. A method as recited in claim 54, wherein said hard material is selected from the group consisting of metal oxide ceramics, carbides, metal nitrides, powdered metals, metal fibers, refractory metals and combinations thereof.
56. A method as recited in claims 55 wherein said hard material is mixed with a polymer selected from the group consisting of thermosetting resin, thermoplastic resin, thermosetting elastomer, thermoplastic elastomer and combinations thereof.
57. A method as recited in claims 56 wherein said hard material is mixed with a polymer selected from the group consisting of thermosetting resin, thermoplastic resin, thermosetting elastomer, thermoplastic elastomer and combinations thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65761200A | 2000-09-08 | 2000-09-08 | |
| US09/657612 | 2000-09-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2356718A1 true CA2356718A1 (en) | 2002-03-08 |
Family
ID=24637924
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2356718 Abandoned CA2356718A1 (en) | 2000-09-08 | 2001-08-30 | Progressing cavity pump with constant liner thickness |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2356718A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013171630A1 (en) * | 2012-05-15 | 2013-11-21 | Sabic Innovative Plastics Ip B.V. | Polyetherimide pump |
-
2001
- 2001-08-30 CA CA 2356718 patent/CA2356718A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013171630A1 (en) * | 2012-05-15 | 2013-11-21 | Sabic Innovative Plastics Ip B.V. | Polyetherimide pump |
| CN104271952A (en) * | 2012-05-15 | 2015-01-07 | 沙特基础创新塑料Ip私人有限责任公司 | Polyetherimide pump |
| US9429149B2 (en) | 2012-05-15 | 2016-08-30 | Sabic Global Technologies B.V. | Polyetherimide pump |
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