Submersible linear motor with pressure balancer

Abstract

The utility model discloses a submersible linear motor with a pressure balancer, which comprises a stator arranged in an inner cavity of the stator and a rotor doing linear motion along the stator, and is characterized in that the inner cavity of the stator is provided with the pressure balancer, and the pressure balancer comprises a balancing capsule, an oil guide groove and a pressure balancer cavity; the balancing capsule divides the pressure balancer cavity into a pressure balancer inner cavity and a pressure balancer outer cavity, the pressure balancer inner cavity is communicated with the oil guide groove, and the pressure balancer outer cavity is communicated with the external environment; according to the utility model, the submersible linear motor is provided with the pressure balancer, and the outer cavity of the pressure balancer is communicated with the external environment, so that the influence of the pressure generated by the reciprocating motion of the rotor on the balance capsule is avoided, and the problem that under the condition of full-rigid sealing of the existing submersible linear motor, the sealing performance of the submersible linear motor is influenced is solved. The internal and external pressure difference of the motor is large; and the structure is easy to generate microcrack leakage.

Description

Technical Field

[0001] This utility model relates to the field of submersible linear motors, and more specifically, to a submersible linear motor with a pressure balancer. Background Technology

[0002] A submersible linear motor is a power unit for artificial lift equipment in oil and gas wells. Submerged in the oil layer, it directly drives a plunger pump by reciprocating in a straight line, thus lifting the well fluid. The operating environment of a submersible linear motor is within the oil layer of an oil well, often thousands of meters below the surface. The environment is under immense pressure, and the well fluid composition is complex, containing oil, water, gas, and various corrosive substances, posing significant challenges to the motor's protection.

[0003] Existing technologies, to avoid damage to the stator sealing structure caused by the large internal and external pressure difference, utilize the incompressibility of liquids by filling the stator cavity with insulating fluid. However, this does not solve the problem of unequal pressures between the internal and external environments of the motor. Considering that the insulating fluid has a larger coefficient of thermal expansion than the rigid structure of the motor, to prevent the insulating fluid from expanding due to motor heating and downhole ambient temperature, thus damaging the sealing structure, the insulating fluid injection must be carried out under the expected maximum operating temperature of the motor, ultimately creating a negative pressure inside the motor cavity and maintaining a partial vacuum environment. However, in actual operation, the motor temperature will not reach the expected maximum temperature, and even if it does briefly reach it, it cannot remain stable at the expected maximum temperature for a long time. Therefore, the motor cavity is always under a negative pressure state. Consequently, the motor's sealing structure is always under a large internal and external pressure difference. Under long-term vibration and impact, microcracks are prone to appear. Under the large pressure difference, well fluid seeps into the motor from the outside through these microcracks, contaminating the internal insulation environment and ultimately causing insulation failure.

[0004] Utility model CN208416890U discloses a submersible linear motor-driven reciprocating oil pumping device with oil chamber pressure balancing. The device includes a discharge valve, an inlet valve, an inlet connector, a pump barrel, a plunger, a cable-connected motor head, an isolation sleeve, an isolation pipe, a motor mover, a motor stator, a protective tube, a motor outer tube, a motor lower connector, and a balancing capsule. The protective tube has balancing holes, and the balancing capsule is fitted over the protective tube, with both ends of the balancing capsule sealed to the protective tube. The balancing capsule covers the balancing holes, forming a balancing chamber between the balancing capsule and the protective tube. This ensures that the pressure of the motor oil in the upper and lower annular cavities is equal to the pressure in the motor lower connector. In this design, the pressure adjustment within the motor is automatically controlled by connecting the balancing capsule through the gap between the mover and stator. However, due to the small gap between the mover and stator, well fluid may be squeezed into or out of the gap in the section containing the balancing chamber during operation, causing very frequent pressure fluctuations. This makes the balancing capsule highly susceptible to fatigue damage, ultimately leading to a significant reduction in the lifespan of the submersible linear motor. Utility Model Content

[0005] To address the problems of the prior art, this invention provides a submersible linear motor with a pressure balancer.

[0006] The technical solution adopted in this utility model is:

[0007] A submersible linear motor with a pressure balancer includes a stator disposed in the inner cavity of the stator and a mover that moves linearly along the stator. The submersible linear motor is further provided with a pressure balancer, which includes a balance capsule, an oil guide groove, and a pressure balancer cavity. The balance capsule divides the pressure balancer cavity into an inner pressure balancer cavity and an outer pressure balancer cavity. The inner pressure balancer cavity is connected to the oil guide groove, and the outer pressure balancer cavity is connected to the external environment. The balance capsule is sealed and fixed inside the submersible motor at both ends.

[0008] Furthermore, the stator inner cavity is formed by a stator inner cylinder, a stator outer cylinder, a motor upper connector, and a motor lower connector, all sealed together. The stator includes a stator core disposed within the stator inner cavity.

[0009] Furthermore, the mover includes a magnetic shaft, and a mover magnetic ring and a mover magnet sleeved on the magnetic shaft.

[0010] Furthermore, the stator outer cylinder is provided with a connecting hole that communicates with the outer cavity of the pressure balancer.

[0011] Furthermore, the inner cavity of the stator is filled with insulating oil.

[0012] Furthermore, the oil guide groove is connected to the stator inner cavity.

[0013] Furthermore, the balancing capsule is made of highly weather-resistant rubber.

[0014] Furthermore, the pressure balancer is installed at the lower motor connector of the submersible motor.

[0015] Furthermore, the pressure balancer is installed on the motor connector of the submersible motor.

[0016] Furthermore, the pressure balancer is located inside the stator of the submersible motor.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] This invention incorporates a pressure balancer into the submersible linear motor. The pressure balancer's outer cavity is connected to the external environment, preventing the pressure generated by the reciprocating motion of the rotor from affecting the balance capsule, thus extending the lifespan of the pressure balancer. It achieves pressure balance between the internal and external spaces of the motor, preventing damage to other rigid structures due to large internal and external pressure differences. Even if microcracks appear in the motor structure due to vibration or impact, the balance capsule can expand or contract to transfer the pressure from the outer cavity of the pressure balancer to the inner cavity of the stator, eliminating the pressure difference between the two ends of the microcrack. This reduces the probability of well fluid seepage or leakage, improves the reliability of the submersible linear motor, and extends the equipment's lifespan. Attached Figure Description

[0019] Figure 1 This refers to a submersible linear motor with a pressure balancer, as described in Example 1.

[0020] Figure 2 This refers to a submersible linear motor with a pressure balancer, as shown in Example 2.

[0021] Figure 3 This is a submersible linear motor with a pressure balancer, as shown in Example 3.

[0022] The components include: 1. Stator; 2. Mover; 3. Motor tailpipe; 4. Motor upper connecting pipe; 11. Stator inner cylinder; 12. Stator core; 13. Stator outer cylinder; 14. Stator inner centralizer; 15. Motor lower connector with pressure balancer; 151. Lower connector inner limit stop; 152. Lower connector oil guide groove; 153. Lower connector pressure balancer outer cylinder; 154. Lower connector balance capsule; 155. Lower connector sealing hose clamp; 156. Lower connector pressure balancer outer cavity; 157. Lower connector pressure balancer inner cavity; 158. Lower connector connecting hole; 16. Motor lead wire; 17. Motor upper connector with pressure balancer; 171. Upper connector inner centralizer; 172. Upper connector oil guide groove; 173. Upper connector... 174. Upper joint pressure balancer outer cylinder; 175. Upper joint balance capsule; 176. Upper joint sealing hose clamp; 177. Upper joint pressure balancer outer cavity; 178. Upper joint pressure balancer inner cavity; 18. Upper joint connecting hole; 19. Stator inner pressure balance stub; 10. Pressure balance stub inner centralizer; 10. Pressure balance stub oil guide groove; 11. Pressure balance stub outer cylinder; 12. Pressure balance stub balance capsule; 13. Pressure balance stub sealing hose clamp; 14. Pressure balance stub outer cavity; 15. Pressure balance stub inner cavity; 16. Pressure balance stub connecting hole; 177. Mover base; 28. Mover magnetic ring; 29. ​​Mover magnet; 20. Mover limit stop. Detailed Implementation

[0023] To clearly illustrate the technical features of this solution, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application; however, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below. Furthermore, it should be understood in the description of this application that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified. In this application, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In this application, unless otherwise explicitly specified and limited, "on" or "below" a second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0024] Example 1

[0025] Please see Figure 1 This embodiment provides a submersible linear motor with a pressure balancer, wherein the pressure balancer is installed at the lower connector of the submersible linear motor.

[0026] A submersible linear motor with a pressure balancer includes a stator 1 disposed in the inner cavity of the stator and a mover 2 that moves linearly along the stator. The submersible linear motor is provided with a lower connector 15 with a pressure balancer. The pressure balancer includes a lower connector balancing capsule 154, a lower connector oil guide groove 152, and a pressure balancer cavity. The lower connector balancing capsule 154 divides the pressure balancer cavity into a lower connector pressure balancer inner cavity 157 and a lower connector pressure balancer outer cavity 156. The lower connector pressure balancer inner cavity 157 is connected to the lower connector oil guide groove 152, and the lower connector pressure balancer outer cavity 156 is connected to the external environment. The lower connector balancing capsule 154 is sealed and fixed at both ends inside the submersible motor.

[0027] The stator cavity is formed by a stator inner cylinder 11, a stator outer cylinder 13, a motor upper connector, and a motor lower connector, all sealed together. The stator 1 includes a stator core 12 located in the stator cavity. The mover 2 includes a magnetic shaft, a mover magnetic ring 23 and a mover magnet 22 sleeved on the magnetic shaft, and the stator cavity is filled with insulating oil.

[0028] The outer cylinder 153 of the lower connector pressure balancer is provided with a lower connector connecting hole 158, which is connected to the outer cavity 156 of the lower connector pressure balancer; the lower connector oil guide groove 152 is connected to the inner cavity of the stator; the lower connector balance capsule 154 is fixed inside the submersible motor by the lower connector sealing hose clamp 155; the balance capsule is made of fluororubber.

[0029] After adding the inner limit stop 151 to the lower connector, the stator inner cavity is connected to the lower connector pressure balancer inner cavity 157 via the lower connector oil guide groove 152. It is separated from the lower connector pressure balancer outer cavity 156 via the lower connector balance capsule 154 and the lower connector sealing hose clamp 155. The lower connector pressure balancer outer cavity 156 is connected to the surrounding environment downhole via the lower connector connecting hole 158. When the pressure inside and outside the pressure balancer is unbalanced, the lower connector balance capsule 154 expands or contracts to achieve equal pressure inside and outside. Friction easily occurs between the mover base 21 and the inner wall of the motor lower connector 15 with pressure balancer. A wear-resistant alloy layer is metallurgically bonded to the surface of the mover base 21 boss, and the inner wall of the motor lower connector 15 with pressure balancer is reinforced with chrome plating to improve equipment lifespan.

[0030] Example 2

[0031] Please see Figure 2 This embodiment provides a submersible linear motor with a pressure balancer, wherein the pressure balancer is installed on the motor connector of the submersible linear motor.

[0032] A submersible linear motor with a pressure balancer includes a stator 1 disposed in the inner cavity of the stator and a mover 2 that moves linearly along the stator. The submersible linear motor is provided with an upper connector 17 with a pressure balancer. The pressure balancer includes an upper connector balancing capsule 174, an upper connector oil guide groove 172, and a pressure balancer cavity. The upper connector balancing capsule 174 divides the pressure balancer cavity into an upper connector pressure balancer inner cavity 177 and an upper connector pressure balancer outer cavity 176. The upper connector pressure balancer inner cavity 177 is connected to the upper connector oil guide groove 172, and the upper connector pressure balancer outer cavity 176 is connected to the external environment. The upper connector balancing capsule 174 is sealed and fixed at both ends inside the submersible motor.

[0033] The stator cavity is formed by a stator inner cylinder 11, a stator outer cylinder 13, a motor upper connector, and a motor lower connector, all sealed together. The stator 1 includes a stator core 12 located in the stator cavity. The mover 2 includes a magnetic shaft, a mover magnetic ring 23 and a mover magnet 22 sleeved on the magnetic shaft, and the stator cavity is filled with insulating oil.

[0034] The outer cylinder 173 of the upper connector pressure balancer is provided with an upper connector communication hole 178, which is connected to the outer cavity 176 of the upper connector pressure balancer; the upper connector oil guide groove 172 is connected to the inner cavity of the stator; the upper connector balance capsule 174 is fixed inside the submersible motor by the upper connector sealing hose clamp 175; the balance capsule is made of fluororubber.

[0035] The advantage of placing the pressure balancer on the upper connector of the submersible linear motor is that an internal stabilizer 171 is added inside the upper connector 17 with the pressure balancer, which can effectively straighten the mover 2 and prevent the mover 2 from rubbing against the inner wall of the upper connector 17 with the pressure balancer, thus avoiding damage. However, the upper connector needs to lead out multiple motor leads 16. For a commonly used three-phase motor, at least three motor leads 16 need to be led out, making the structure relatively more complex. In addition, the upper connector needs to be connected to the upper connecting pipe 4 of the motor and needs to bear the entire load when the motor is running, thus placing high demands on the structural strength.

[0036] Example 3

[0037] Please see Figure 3 This embodiment provides a submersible linear motor with a pressure balancer, wherein the pressure balancer is installed inside the stator of the submersible linear motor.

[0038] A submersible linear motor with a pressure balancer includes a stator 1 disposed in the inner cavity of the stator and a mover 2 that moves linearly along the stator. The submersible linear motor is provided with an internal pressure balancing section 18, which includes a pressure balancing section balancing capsule 184, a pressure balancing section oil guide groove 182, and a pressure balancer cavity. The pressure balancing section balancing capsule 184 divides the pressure balancer cavity into an inner pressure balancing section cavity 187 and an outer pressure balancing section cavity 186. The inner pressure balancing section cavity 187 is connected to the pressure balancing section oil guide groove 182, and the outer pressure balancing section cavity 186 is connected to the external environment. The pressure balancing section balancing capsule 184 is sealed and fixed at both ends inside the submersible motor.

[0039] The stator cavity is formed by a stator inner cylinder 11, a stator outer cylinder 13, a motor upper connector, and a motor lower connector, all sealed together. The stator 1 includes a stator core 12 located in the stator cavity. The mover 2 includes a magnetic shaft, a mover magnetic ring 23 and a mover magnet 22 sleeved on the magnetic shaft, and the stator cavity is filled with insulating oil.

[0040] The outer cylinder 183 of the pressure balancing short section is provided with a pressure balancing short section connecting hole 188, which is connected to the outer cavity 186 of the pressure balancing short section; the oil guide groove 182 of the pressure balancing short section is connected to the inner cavity of the stator; the balancing capsule 184 of the pressure balancing short section is fixed inside the submersible motor by a pressure balancing short section sealing hose clamp 185; the balancing capsule is made of AFLAS rubber.

[0041] The advantage of placing the pressure balancer on the upper connector of the submersible linear motor is that an internal stabilizer 171 is added inside the upper connector 17 with the pressure balancer, which can effectively straighten the mover 2 and prevent the mover 2 from rubbing against the inner wall of the upper connector 17 with the pressure balancer, thus avoiding damage. However, the upper connector needs to lead out multiple motor leads 16. For a commonly used three-phase motor, at least three motor leads 16 need to be led out, making the structure relatively more complex. In addition, the upper connector needs to be connected to the upper connecting pipe 4 of the motor and needs to bear the entire load when the motor is running, thus placing high demands on the structural strength.

[0042] When the pressure balancer is installed inside the stator of the submersible linear motor, multiple pressure balance short sections 18 need to be opened in the stator, which are used not only for guiding oil but also for connecting the stator cores 12 on both sides. When the pressure balance short section 18 is placed inside the stator, in order to ensure that the pitch of the moving and stator is consistent and to ensure the thrust of the motor during operation, the length of the pressure balance short section 18 must be strictly adjusted according to the pitch of the motor.

[0043] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A submersible linear motor with a pressure balancer, comprising a stator disposed in the inner cavity of the stator and a mover that moves linearly along the stator, characterized in that: The submersible linear motor is also equipped with a pressure balancer, which includes a balance capsule, an oil guide groove, and a pressure balancer cavity. The balance capsule divides the pressure balancer cavity into an inner pressure balancer cavity and an outer pressure balancer cavity. The inner pressure balancer cavity is connected to the oil guide groove, and the outer pressure balancer cavity is connected to the external environment. The balance capsule is sealed and fixed inside the submersible motor at both ends.

2. The submersible linear motor with a pressure balancer according to claim 1, characterized in that: The stator cavity is formed by a sealed connection of an inner stator cylinder, an outer stator cylinder, an upper motor connector, and a lower motor connector. The stator includes a stator core disposed within the stator cavity.

3. A submersible linear motor with a pressure balancer according to claim 2, characterized in that: The stator outer cylinder is provided with a connecting hole that connects to the outer cavity of the pressure balancer.

4. A submersible linear motor with a pressure balancer according to claim 1, characterized in that: The stator cavity is filled with insulating oil.

5. A submersible linear motor with a pressure balancer according to claim 1, characterized in that: The mover includes a magnetic shaft, a mover magnetic ring and a mover magnet fitted onto the magnetic shaft.

6. A submersible linear motor with a pressure balancer according to claim 1, characterized in that: The oil guide groove is connected to the inner cavity of the stator.

7. A submersible linear motor with a pressure balancer according to claim 1, characterized in that: The balancing capsule is made of highly weather-resistant rubber.

8. A submersible linear motor with a pressure balancer according to claim 1, characterized in that: The pressure balancer is installed at the lower connector of the submersible motor.

9. A submersible linear motor with a pressure balancer according to claim 1, characterized in that: The pressure balancer is installed on the motor connector of the submersible motor.

10. A submersible linear motor with a pressure balancer according to claim 1, characterized in that: The pressure balancer is installed inside the stator of the submersible motor.

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