Shielding pump stator sealing system and shielding pump

Abstract

The utility model relates to the technical field of shielded pump discloses a shielded pump and its stator sealing system, be applicable to the conveyance low temperature liquid medium. The shielded pump includes the pump shell, sets up in the stator system and rotor system of pump shell, wherein the stator system contains electrical unit and sealing assembly, and sealing assembly is composed of outer support cylinder, inner shielded sleeve and the end plate of both ends, the annular hole is formed annular support in the middle of end plate, bearing support ring is arranged in end plate annular support, and inner shielded sleeve end part inserts the clearance between end plate and bearing support ring, and end plate is fixed in outer support cylinder through welding, and bearing support ring is fixed with end plate through welding, forms the annular cavity of sealing to accommodate stator electrical unit. This sealing system can keep the minimum air gap of rotor and stator at the same time, realizes reliable liquid isolation to stator electrical unit, improves the stability and sealing property of welding operation, guarantees the safe operation of pump under low temperature environment and the ability of high -efficient conveyance liquid medium.

Description

Technical Field

[0001] This utility model relates to the field of canned motor pump technology, specifically to a canned motor pump stator sealing system and a canned motor pump. Background Technology

[0002] A canned motor pump is a type of pump used to transport liquid media. Its overall structure mainly includes a pump casing, a stator system, and a rotor system. Both the stator and rotor are housed within the pump casing; the stator has a cylindrical structure, and the rotor is installed inside the stator. During pump operation, the liquid media flows through the pump body, therefore the stator system is immersed in the liquid media during operation.

[0003] The stator houses electrical units that must be completely isolated from the liquid medium during pump operation; otherwise, liquid infiltration can damage the components or even cause pump failure. Therefore, the stator system requires a sealing assembly to achieve liquid isolation, protecting the electrical units without affecting the air gap between the rotor and stator.

[0004] To ensure pump efficiency, the air gap between the rotor and stator needs to be as small as possible. This requires the stator sealing assembly (corresponding to the rotor position) to be designed with a thin-walled structure, allowing the rotor to rotate freely within the small air gap. However, in existing technologies, the installation and fixing of such thin-walled sealing assemblies present significant challenges: regardless of whether welding or mechanical connection methods are used, the thin-walled assembly is prone to deformation or uneven stress, leading to unstable seals or difficulty in reliably securing it. This problem is even more pronounced in cryogenic liquid environments (liquid nitrogen, liquid oxygen, liquid hydrogen, etc.), significantly increasing the installation difficulty and leakage risk of the sealing assembly, thus limiting the long-term stable operation of the canned motor pump under cryogenic conditions. Utility Model Content

[0005] In view of the above-mentioned deficiencies or defects in the prior art, the present invention provides a canned pump stator sealing system and a canned pump. The sealing system can be designed with a thinner inner shielding sleeve (2b), reducing the air gap between the stator and the rotor, improving the pump body working efficiency, and ensuring the sealing stability of the stator in low temperature environment.

[0006] To achieve the above objectives, this utility model provides a shielded pump stator sealing system, comprising: External support cylinder; The inner shielding sleeve is fitted inside the outer support cylinder, forming an annular cavity between the inner shielding sleeve and the outer support cylinder; End plates are located at both ends of the annular cavity. The end plates are annular in shape, with an annular hole in the middle to form an annular support for accommodating the bearing support ring. The bearing support ring is located within the annular support of the end plate; The end plate is fixed to the end of the outer support cylinder by welding to form a ring weld, which seals the gap between the end plate and the outer support cylinder. The end of the inner shielding sleeve is inserted into the gap between the annular support of the end plate and the outer circumference of the bearing support ring. The end plate and the bearing support ring are fixed by welding, and the weld seals the gap between the end plate and the bearing support ring. The outer support cylinder, inner shielding sleeve, and end plates on both sides form a sealed annular cavity to accommodate the stator electrical unit.

[0007] Preferably, the end plate and the outer end face of the bearing support ring together define a stepped surface, and the weld is formed at the junction of the stepped surface, forming an annular weld after welding to achieve a seal.

[0008] Preferably, the bearing support ring protrudes outward relative to the outer end face of the end plate, so that a stepped surface is formed between the outer peripheral surface of the bearing support ring and the outer end face of the end plate. The weld is arranged in a ring at the junction of the stepped surface to achieve a sealed weld between the end plate and the bearing support ring.

[0009] Preferably, the annular hole in the middle of the end plate is a stepped hole structure, and the end face of the bearing support ring is flush with the outer end face of the end plate; The stepped annular surface of the stepped hole and the outer circumferential surface of the bearing support ring form a stepped surface, and the weld is formed at the junction of the two, thereby achieving an annular seal.

[0010] Preferably, the end of the inner shielding sleeve extends to the welding position between the end plate and the bearing support ring. The end of the inner shielding sleeve is fitted and connected to the bearing support ring and the end plate. After welding, the three form an integrated sealing structure, thereby sealing the gap between the end plate, the bearing support ring and the inner shielding sleeve.

[0011] Preferably, the inner shielding sleeve is made of Hastelloy material; the end plate and the bearing support ring are made of the same material.

[0012] The present invention also proposes a shielded pump, comprising: Pump casing; The stator assembly and rotor assembly are disposed within the pump casing; The stator assembly includes an electrical unit and a sealing system for sealing the electrical unit, wherein the sealing system is the canned pump stator sealing system mentioned above; The rotor assembly is mounted on the bearing support ring via bearings, and bearing assemblies are respectively provided at both ends of the rotor shaft.

[0013] The pump casing is provided with an inlet and an outlet at both ends, respectively. A flow channel is formed between the outer wall of the sealing system and the pump casing, and the flow channel is connected to the inlet and outlet at both ends of the pump body, respectively.

[0014] The canned motor pump stator sealing system and the canned motor pump using the above-mentioned technical solution of this utility model have the following effects: This invention completely seals the connection gaps between components by forming annular welds between the end plate and the outer support cylinder, and between the end plate and the bearing support ring, thus forming a continuous and sealed welded encapsulation structure. As a result, the sealed annular cavity formed inside the stator system effectively prevents liquid infiltration in operating environments where the system is immersed in liquid media for extended periods, fundamentally avoiding the problems of electrical units becoming damp or short-circuited, and significantly improving the protection level and service life of the stator system.

[0015] The end of the inner shielding sleeve is inserted into the gap between the end plate and the bearing support ring, and the area is welded closed in this region. This provides a clear welding operation space, and the weld position is fixed and easy to control. By setting a stepped surface structure between the end plate and the bearing support ring, a stable molten pool can be formed at the welding site, making it easier to ensure the weld depth and weld formation quality, thereby ensuring the uniformity and strength of the sealed connection.

[0016] The integrated design of the sealing system and bearing support structure allows the rotor assembly to be directly mounted on the bearing support ring, simplifying the assembly process and reducing assembly errors between the rotor and stator. The sealing cavity and pump body flow channels are independent of each other, ensuring that the flow of coolant or pumped fluid does not affect the insulation and sealing performance of the electrical components, thereby improving the overall operational reliability and ease of maintenance.

[0017] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the shielded pump of this utility model; Figure 2 yes Figure 1 The enlarged view at point A is a schematic diagram of the connection relationship of the sealing system.

[0019] Explanation of reference numerals in the attached figures 1-Pump casing, 1a-Pump casing body, 1b-Pump casing end cover; 2-Electrical Unit, 3-Sealing system, 3a-Outer support cylinder, 3b-Inner shielding sleeve, 3c-End plate, 3d-Bearing support ring; 4-Rotor assembly, 5-Impeller. Detailed Implementation

[0020] The specific embodiments of this utility model are described in detail below. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0021] In this utility model, unless otherwise stated, "inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself.

[0022] This utility model provides a canned pump stator sealing system (see attached document). Figure 1 and attached Figure 2 This is a structural improvement of the stator section of the canned motor pump, mainly used to achieve a highly reliable seal in the stator cavity, while also ensuring the welding stability and sealing integrity of the end bearing support structure. The system mainly includes core components such as an outer support cylinder 3a, an inner shielding sleeve 2b, an end plate 3c, and a bearing support ring 3d. These components are welded and nested together to form a sealed annular cavity to accommodate the stator coils and other electrical units 2.

[0023] The outer support cylinder 3a has a cylindrical structure and is used to support and protect the internal stator assembly. The inner shielding sleeve 2b is fitted inside the outer support cylinder 3a, and the two define an annular cavity to accommodate the stator core and stator windings and other electrical units 2. The end plates 3c are fixedly installed at both ends of the outer support cylinder 3a and are sealed to the outer support cylinder 3a by an annular weld, thereby closing the openings at both ends of the annular cavity.

[0024] An annular support is provided in the middle of the end plate 3c, and the bearing support ring 3d is embedded in the annular support. The end plate 3c and the bearing support ring 3d are fixed together by welding, and the weld seals the gap between them, making the welded area part of the sealing structure. The end of the inner shielding sleeve 2b is inserted into the gap between the annular support of the end plate 3c and the outer periphery of the bearing support ring 3d, and its end edge extends to the welded area so that it can form an integral connection with the end plate 3c and the bearing support ring 3d after welding, ensuring the sealing integrity of the stator cavity.

[0025] The outer support cylinder 3a, end plate 3c, bearing support ring 3d, and inner shielding sleeve 2b together form a completely sealed annular space. The stator core is fixed to the outer wall of the inner shielding sleeve 2b, and the windings and their leads are sealed within the annular cavity. This annular cavity is completely isolated from the pumping medium, thereby preventing the medium from seeping into the electrical components and ensuring the long-term stable operation of the canned pump in high-pressure, high-temperature, or corrosive media environments.

[0026] In the stator sealing system 3, end plates 3c are located at both ends of the annular cavity, forming an annular structure with an annular hole in the middle to form an annular support. The bearing support ring 3d is embedded in the annular support of the end plate 3c and fixed to the end plate 3c by welding. The welding between the end plate 3c and the bearing support ring 3d not only fixes the position of the bearing support ring 3d but also seals the gap between the end plate 3c and the bearing support ring 3d, thus forming part of the sealing structure.

[0027] The primary function of the bearing support ring 3d is to support the rotor bearing, enabling stable rotor rotation. Both ends of the rotor shaft are mounted on the bearing support ring 3d via bearings. The bearing support ring 3d is fixed within the stator sealing system 3 by end plates 3c, providing reliable axial and radial support for the rotor. This structure achieves an organic combination of rotor support and stator sealing, ensuring stable rotor operation in cryogenic liquid media while preventing liquid media from seeping into the stator.

[0028] During assembly, the outer edge of end plate 3c is welded to the end of outer support cylinder 3a, forming the first annular sealing weld; the bearing support ring 3d is welded to the inner side of the annular support of end plate 3c, forming the second sealing weld. The two welds constitute a double sealing system, further improving the sealing redundancy and welding reliability of the system.

[0029] Through the above structure, the stator sealing system 3 achieves comprehensive functions of mechanical load-bearing, sealing, leak prevention, and electrical isolation. In particular, the stepped welding structure between the end plate 3c and the bearing support ring 3d makes the weld position controllable and the welding stress distribution more uniform, significantly improving welding reliability and sealing performance. The entire system has a compact structure, good assemblability, high temperature and corrosion resistance, and is suitable for canned pumps in various working media and complex operating environments.

[0030] Stepped surface design: In the stator sealing system 3, the outer end faces of the end plate 3c and the bearing support ring 3d together form an annular stepped surface, which is used for welding fixation and sealing. The stepped surface design facilitates welding operations while ensuring that the weld reliably seals the gap between the end plate 3c and the bearing support ring 3d.

[0031] There are two ways to form a stepped surface: a. The bearing support ring 3d protrudes outward relative to the outer end face of the end plate 3c, and the outer circumferential surface of the bearing support ring 3d and the outer end face of the end plate 3c form an annular stepped surface. The weld seam forms an annular structure at the junction of the stepped surface, fixing the bearing support ring 3d to the end plate 3c and sealing the gap between them to achieve a reliable seal.

[0032] b. The annular hole in the middle of end plate 3c is designed as a stepped hole structure, and the end face of bearing support ring 3d is flush with the outer end face of end plate 3c. The stepped annular surface of the stepped hole and the outer peripheral surface of bearing support ring 3d form a stepped surface. The weld seam forms an annular sealing structure at the junction of the stepped surfaces, realizing the fixation and sealing of end plate 3c and bearing support ring 3d.

[0033] With the aforementioned stepped surface design, welding operations can be performed on a relatively wide welding surface, reducing the risk of damage to the inner shielding sleeve 2b, while ensuring that the weld structure is robust and reliable, and improving the overall stability of the stator sealing system 3.

[0034] Welding of inner shielding sleeve 2b: The end of the inner shielding sleeve 2b extends to the welding point between the end plate 3c and the bearing support ring 3d. During installation, the end is inserted into the gap between the annular support of the end plate 3c and the outer circumference of the bearing support ring 3d. Through this structural design, the end of the inner shielding sleeve 2b fits tightly against the end plate 3c and the bearing support ring 3d.

[0035] During the welding operation, the molten pool formed by the welding of end plate 3c and bearing support ring 3d partially covers the end of inner shielding sleeve 2b, so that the three form an integrated sealed connection structure after welding. This structure seals the gap between end plate 3c, bearing support ring 3d and inner shielding sleeve 2b, ensuring that the stator electrical unit 2 in the sealed cavity is completely isolated from the liquid medium. At the same time, the weld is strong and can withstand thermal stress and mechanical vibration in low-temperature environments.

[0036] This design ensures a reliable seal even if the inner shielding sleeve 2b is thin and its material differs from that of the end plate 3c or the bearing support ring 3d, thus preventing damage to the inner shielding sleeve 2b during welding and improving the stability and durability of the stator sealing system 3.

[0037] Assembly and installation: During assembly, first, the inner shielding sleeve 2b is fitted into the outer support cylinder 3a, ensuring that the two are coaxial and maintaining the annular cavity clearance. Then, the end plate 3c is installed at both ends of the annular cavity, and the bearing support ring 3d is placed in the annular support of the end plate 3c.

[0038] The end of the inner shielding sleeve 2b is inserted into the gap between the annular support of the end plate 3c and the outer circumference of the bearing support ring 3d, ensuring that the end plate 3c, the bearing support ring 3d, and the inner shielding sleeve 2b are tightly fitted. In this state, the end plate 3c is welded to the outer support cylinder 3a and the end plate 3c is welded to the bearing support ring 3d to form an annular weld, completely sealing the gaps between the components.

[0039] Shielded pump: This canned motor pump consists of a pump casing 1, a stator sealing system 3, and a rotor assembly 4.

[0040] The pump casing 1 consists of a casing body 1a and end caps 1b. The end caps are welded to the casing body to form an annular external seal, ensuring no leakage of liquid outside the pump body. A stator sealing system 3 is installed inside the pump casing 1. The stator system includes an electrical unit 2 and its sealing assembly. The sealing assembly is enclosed by an outer support cylinder 3a, an inner shielding sleeve 2b, and two end plates 3c to form a sealed annular cavity to house the electrical unit 2. A rotor assembly 4 is installed inside the stator. The rotor is mounted on a bearing support ring 3d on the end plate 3c via bearings. Bearings are provided at both ends of the rotor shaft to support the rotor and ensure its coaxiality and stability during operation.

[0041] Inside the pump body, a flow channel is formed between the outer wall of the stator sealing system 3 and the pump casing 1a for the flow of liquid medium. The two ends of the flow channel are connected to the inlet and outlet of the pump casing 1, respectively, to realize the effective circulation of liquid in the pump body.

[0042] This structure achieves overall sealing of the pump body while ensuring stable operation of the stator and rotor in low-temperature liquid media, balancing sealing performance and motor operating efficiency.

[0043] In this canned motor pump, an annular flow channel is formed between the outer wall of the stator sealing system 3 and the pump casing 1a. After the liquid medium enters the pump body through the inlet at one end of the pump casing 1, it enters the working area of ​​the rotor impeller 5 and is driven by the impeller 5 to flow evenly along the flow channel. After passing through the annular gaps on both sides between the outer wall of the stator sealing system 3 and the inner wall of the pump casing 1, it is discharged from the outlet at the other end of the pump casing 1, thus realizing continuous liquid circulation.

[0044] This flow channel design ensures smooth liquid flow within the pump body while reducing direct impact on the stator sealing system 3. A certain isolation distance is formed between the flow channel and the sealing system 3, effectively reducing the impact of liquid vibration and pressure fluctuations on the sealing components, ensuring the safety of the internal electrical unit 2 of the stator and the stability of the sealing system 3.

[0045] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0046] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this utility model will not describe the various possible combinations separately.

[0047] Furthermore, various different embodiments of this utility model can be combined in any way, as long as they do not violate the spirit of this utility model, they should also be regarded as the content disclosed by this utility model.

Claims

1. A stator sealing system for a canned motor pump, characterized in that, include: Outer support cylinder (3a); The inner shielding sleeve (2b) is fitted inside the outer support cylinder (3a) and forms an annular cavity with the outer support cylinder (3a); End plates (3c) are located at both ends of the annular cavity. The end plates (3c) are annular in shape, with an annular hole in the middle to form an annular support for accommodating the bearing support ring (3d). The bearing support ring (3d) is located within the annular support of the end plate (3c); The end plate (3c) is fixed to the end of the outer support cylinder (3a) by welding to form an annular weld, which seals the gap between the end plate (3c) and the outer support cylinder (3a). The end of the inner shielding sleeve (2b) is inserted into the gap between the annular support of the end plate (3c) and the outer circumference of the bearing support ring (3d). The end plate (3c) and the bearing support ring (3d) are fixed by welding, and the weld seals the gap between the end plate (3c) and the bearing support ring (3d). The outer support cylinder (3a), the inner shielding sleeve (2b), and the end plates (3c) on both sides form a sealed annular cavity to accommodate the stator electrical unit (2).

2. The sealing system according to claim 1, characterized in that, The outer end face of the end plate (3c) and the bearing support ring (3d) together define a stepped surface. The weld is formed at the junction of the stepped surface, and after welding, a ring weld is formed to achieve a seal.

3. The sealing system according to claim 2, characterized in that, The bearing support ring (3d) protrudes outward relative to the outer end face of the end plate (3c), so that a stepped surface is formed between the outer peripheral surface of the bearing support ring (3d) and the outer end face of the end plate (3c); The weld is arranged in a ring at the junction of the stepped surfaces to achieve a sealed weld between the end plate (3c) and the bearing support ring (3d).

4. The sealing system according to claim 2, characterized in that, The annular hole in the middle of the end plate (3c) is a stepped hole structure, and the end face of the bearing support ring (3d) is flush with the outer end face of the end plate (3c). The stepped annular surface of the stepped hole and the outer peripheral surface of the bearing support ring (3d) form a stepped surface, and the weld is formed at the junction of the two to achieve an annular seal.

5. The sealing system according to claim 2, characterized in that, The end of the inner shielding sleeve (2b) extends to the welding part of the end plate (3c) and the bearing support ring (3d). The end of the inner shielding sleeve (2b) is closely connected to the bearing support ring (3d) and the end plate (3c). After the three are welded, they form an integrated sealing structure, thereby sealing the gap between the end plate (3c), the bearing support ring (3d) and the inner shielding sleeve (2b).

6. The sealing system according to claim 1, characterized in that, The inner shielding sleeve (2b) is made of Hastelloy material; the end plate (3c) is made of the same material as the bearing support ring (3d).

7. A canned pump, characterized in that, include: Pump casing (1); The stator assembly and rotor assembly (4) are disposed within the pump casing (1). The stator assembly includes an electrical unit (2) and a sealing system (3) for sealing the electrical unit (2), wherein the sealing system (3) is the shielded pump stator sealing system (3) according to any one of claims 1 to 6. The rotor assembly (4) is mounted on the bearing support ring (3d) via bearings, and bearing assemblies are provided at both ends of the rotor shaft.

8. The shielded pump according to claim 7, characterized in that, The pump casing (1) is provided with an inlet and an outlet at both ends respectively; A flow channel is formed between the outer wall of the sealing system (3) and the pump casing (1), and the flow channel is connected to the inlet and outlet at both ends of the pump body, respectively.

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