Welded canned shield pump

Abstract

The utility model relates to the field of shielding pump discloses a kind of welded sealing type shielding pumps, it includes pump shell assembly, stator assembly and rotor assembly.Pump shell assembly is made of pump shell barrel and the pump shell end cap being set at both ends, and it is sealed by annular weld between pump shell end cap and pump shell barrel.Stator assembly includes electrical unit and shield sleeve, and shield sleeve is made of outer support cylinder, inner shield sleeve and end plate, and end plate forms annular seal with outer support cylinder and inner shield sleeve respectively by welding, and constitutes closed cavity to isolate liquid medium.Rotor assembly is sleeved in stator assembly, and impeller is installed at both ends of rotor shaft.Pump shell end cap is equipped with liquid inlet and liquid outlet, and liquid enters pump body through liquid inlet, and flows to liquid outlet discharge under the drive of impeller through the flow channel between stator and pump shell.The shielding pump structure adopts full-welded sealing, cancels mechanical fastening and gasket sealing, is suitable for low-temperature liquid delivery, and ensures long-term sealing stability of pump body.

Description

Technical Field

[0001] This utility model relates to the field of shielded pumps, and specifically to a welded sealed shielded pump. Background Technology

[0002] Existing cryogenic liquid pumps typically employ an integrated structure of a shielded motor and pump body, used for conveying cryogenic liquid media such as liquid nitrogen, liquid hydrogen, and liquid helium. This type of pump body structure generally consists of multiple independent components mechanically connected; for example, the end cap and pump casing are bolted together, and sealing gaskets or O-rings are installed at the connection points to prevent liquid leakage.

[0003] However, mechanical connection structures that can reliably seal at room temperature may face a significant risk of seal failure at low temperatures. This is because pump casings, end covers, and gaskets are often made of different materials when conveying cryogenic media. Upon cooling, these parts shrink unevenly, leading to widened joint gaps and reduced sealing ring clamping force. Traditional rubber or polymer sealing materials tend to harden, lose elasticity, and even develop microcracks at low temperatures. Furthermore, bolted connections are prone to problems such as preload reduction, sealing surface deformation, and stress concentration during repeated cooling-heating cycles.

[0004] These factors make mechanically connected pump bodies highly susceptible to leakage when transporting cryogenic media, which can lead to liquid leakage, pump chamber pressure imbalance, or even equipment failure in severe cases. To improve sealing reliability, some solutions involve layering multiple gaskets at the connection interface or using special cryogenic sealing materials, but these methods are costly to manufacture, complex to assemble, and difficult to maintain stable sealing over the long term. Utility Model Content

[0005] In view of the above-mentioned deficiencies or defects in the prior art, this utility model provides a welded sealed canned pump. The canned pump is designed with a basic structure that allows for the use of a welded sealing structure for both internal and external sealing, thereby improving the sealing stability of the canned pump when conveying low-temperature media.

[0006] To achieve the above objectives, this utility model provides a welded sealed shielded pump, comprising: The pump housing assembly includes a pump housing body and pump housing end caps disposed at both ends of the pump housing body. The end caps are respectively provided with an inlet and an outlet. The pump housing end caps and the pump housing body are sealed by welding with an annular weld. A stator assembly, disposed within a pump housing assembly, includes an electrical unit and a shielding sleeve for sealing the electrical unit. The shielding sleeve includes an outer support cylinder, an inner shielding sleeve, and end plates. The inner shielding sleeve is fitted inside the outer support cylinder to form an annular cylindrical cavity. The two ends of the cavity are sealed by end plates to form a closed cavity, in which the electrical unit is disposed. The end plates are respectively welded to the outer support cylinder and the inner shielding sleeve to form annular welded seals. The rotor assembly is fitted inside the stator assembly, and impellers are installed at both ends of the rotor shaft; a liquid medium flow channel is provided between the shielding sleeve and the pump casing.

[0007] Preferably, an annular hole is formed in the middle of the end plate to form an annular support, and the end of the inner shielding sleeve is attached to the hole wall of the annular support.

[0008] Preferably, the end of the inner shielding sleeve and the end plate are welded and fixed at the annular support by an annular weld.

[0009] Preferably, the end of the outer support cylinder is pressed against the circumferential surface of the end plate, and the outer end face of the end plate is flush with the outer end face of the outer support cylinder.

[0010] Preferably, the outer support cylinder and the end plate are welded together at the end face to form an annular weld.

[0011] Preferably, the end of the pump casing body is pressed against the circumferential surface of the pump casing end cover, and the outer end face of the pump casing end cover is approximately flush with the outer end face of the pump casing body.

[0012] Preferably, the pump casing and the pump casing end cover are welded together at their end faces to form an annular weld.

[0013] Preferably, the inner shielding sleeve is made of Hastelloy; the end plate, outer support cylinder, and pump casing assembly are made of stainless steel, chromium-nickel steel, or nickel-based alloy.

[0014] Preferably, a positioning ring is provided between the pump casing and the stator assembly, and the positioning ring has a hollow structure to allow liquid to flow through.

[0015] The welded-seal canned motor pump proposed in this invention achieves long-term sealing stability in cryogenic liquid medium transportation applications through a fully welded sealing structure of the pump casing assembly, stator assembly, and rotor assembly. Compared with existing canned motor pumps that use mechanical connections and gasket seals, this invention has the following technical advantages: The pump casing and end cover are directly welded together by a circumferential weld, which avoids the loosening and leakage problems caused by thermal shrinkage, stress concentration or material embrittlement of mechanical fasteners and gaskets in low-temperature environments, and improves the reliability of the external seal of the pump body.

[0016] The stator assembly's shielding sleeve consists of an outer support cylinder, an inner shielding sleeve, and end plates. The end plates are welded and sealed to the outer support cylinder and the inner shielding sleeve, forming a sealed cavity that effectively isolates the liquid medium from direct contact with the electrical unit, thereby ensuring the electrical safety and sealing performance inside the stator.

[0017] The inner shielding sleeve is attached to the annular support of the end plate and forms an annular weld along the contact point. The outer support cylinder is welded to the end plate end face, and the pump casing is welded to the end cover end face. The structure is compact and the weld layout is reasonable, which is conducive to the implementation of welding operations and the improvement of weld strength.

[0018] A positioning ring is installed between the pump casing and the stator assembly to ensure the assembly accuracy between the components and to form a liquid medium flow channel, so as to make the liquid dynamic path reasonable and take into account both fluid delivery efficiency and overall pump stability.

[0019] In summary, this utility model achieves highly reliable sealing of the pump body and stator under low-temperature conditions through a fully welded and sealed structural design and reasonable material selection. At the same time, it simplifies the assembly structure and overcomes the technical defects of existing mechanical connection seals that are prone to leakage at low temperatures. It has significant practical value and engineering application prospects.

[0020] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the shielded pump of this utility model; Figure 2 yes Figure 1 Enlarged view of point A in the middle.

[0022] Explanation of reference numerals in the attached figures 1-Pump casing, 1a-Pump casing body, 1b-Pump casing end cover; 2-Stator assembly, 2a-Electrical unit, 2b-Shielding sleeve, 2b1-Outer support cylinder, 2b2-Inner shielding sleeve, 2b3-End plate; 3-Rotor assembly; 4-Impeller; 5-Positioning ring. Detailed Implementation

[0023] 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.

[0024] 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.

[0025] This utility model provides a welded sealed shielded pump (see attached). Figure 1 and attached Figure 2The main structure of the pump assembly includes a pump casing 1, a stator assembly 2, and a rotor assembly 3. The pump casing 1 consists of a casing body 1a and end caps 1b at both ends. The end caps are connected to the casing body 1a via annular welds to form an external seal. The stator assembly 2 is located inside the pump casing 1 and includes an electrical unit 2a and a shielding sleeve 2b. The shielding sleeve 2b consists of an outer support cylinder 2b1, an inner shielding sleeve 2b2, and end plates 2b3. The inner shielding sleeve 2b2 is fitted inside the outer support cylinder 2b1 to form an annular cavity. The two ends of the cavity are sealed by the end plates 2b3, which are connected to the inner shielding sleeve 2b2 and the outer support cylinder 2b1 via annular welds to ensure internal liquid isolation. The rotor assembly 3 is fitted inside the stator assembly 2. Impellers 4 are mounted at both ends of the rotor shaft and supported by bearing support structures at the end plates 2b3. A liquid flow channel is provided between the shielding sleeve 2b of the stator assembly 2 and the casing body 1a, while a positioning ring 5 maintains the assembly accuracy. This structure replaces traditional mechanical connections and gasket seals with a fully welded method, improving sealing reliability and structural stability under low-temperature conditions, while also facilitating processing and assembly.

[0026] Pump casing 1: Pump casing 1 includes a pump casing body 1a and pump casing end caps 1b disposed at both ends of the pump casing body 1a. The pump casing end caps 1b are respectively provided with an inlet and an outlet for the flow of liquid media. The pump casing end caps 1b and the pump casing body 1a are sealed by an circumferential weld, thus forming the external sealing structure of the pump body. The end of the pump casing body 1a presses against the circumferential surface of the pump casing end cap 1b, and the outer end face of the pump casing end cap 1b is approximately flush with the outer end face of the pump casing body 1a. The weld along the end face joint forms a continuous circumferential weld, ensuring the long-term sealing performance of the pump body under low-temperature conditions.

[0027] A liquid medium flow channel is reserved between the inner wall of the pump casing 1a and the shielding sleeve 2b of the stator assembly 2 for the flow of the medium within the pump. A positioning ring 5 with a hollow structure is also installed inside the pump casing 1a to maintain the assembly accuracy of the stator assembly 2 without obstructing the flow of the medium. The material of the pump casing 1 can be selected from stainless steel, chromium-nickel steel, or nickel-based alloys depending on the operating temperature and the properties of the medium to ensure pump body strength and resistance to low-temperature corrosion.

[0028] Stator assembly 2: Stator assembly 2 is disposed inside pump housing 1 and is used to install electrical unit 2a and isolate it from the liquid medium. Stator assembly 2 includes electrical unit 2a and shielding sleeve 2b for sealing electrical unit 2a. The shielding sleeve 2b includes an outer support cylinder 2b1, an inner shielding sleeve 2b2 and an end plate 2b3.

[0029] The outer support cylinder 2b1 is annular, and the inner shielding sleeve 2b2 forms an annular cylindrical cavity, in which the electrical unit 2a is placed. The two ends of the cavity are sealed by end plates 2b3 to form a closed structure. The end plates 2b3 are welded to the inner shielding sleeve 2b2 and the outer support cylinder 2b1 to form annular welded seals, ensuring the isolation of the electrical unit 2a from the liquid medium.

[0030] An annular hole is formed in the middle of the end plate 2b3 to create an annular support. The end of the inner shielding sleeve 2b2 is inserted into this annular hole and abuts against the hole wall. Here, the welding of the end plate 2b3 and the inner shielding sleeve 2b2 forms an annular weld along the circumferential direction from the hole wall. This design, by utilizing the hole wall to support the inner shielding sleeve 2b2, avoids the problems of difficult welding, easy burn-through, or deformation caused by directly welding the end of the thin-walled inner shielding sleeve 2b2.

[0031] The outer support cylinder 2b1 is pressed against the circumferential surface of the end plate 2b3. The outer end face of the end plate 2b3 is roughly flush with the outer end face of the outer support cylinder 2b1, and a circumferential weld is formed at the end face joint. This welding method is similar to the welding of the pump casing 1a and the pump casing end cover 1b, which facilitates the formation of a stable circumferential weld structure and ensures the overall rigidity and sealing reliability of the shielding sleeve 2b and the end plate 2b3.

[0032] Through the above structure, the stator assembly 2 not only ensures the isolation of the internal electrical unit 2a from the medium, but also forms a stable mechanical support, facilitating the installation and operation of the rotor assembly 3. The material selection for the stator assembly 2 can be based on the medium and temperature conditions. The inner shielding sleeve 2b2 is made of Hastelloy, while the end plate 2b3 and the outer support cylinder 2b1 can be made of stainless steel, nickel-based alloy, or chromium-nickel steel to balance low-temperature resistance and weldability.

[0033] Rotor assembly 3: Rotor assembly 3 is fitted inside stator assembly 2 and includes a rotor shaft and impellers 4 mounted at both ends of the rotor shaft. The rotor structure of this invention is not significantly different from existing canned motor pump technology and is mainly used to drive the flow of liquid media to realize the basic pumping function of the pump.

[0034] A cylindrical metal shielding layer is provided on the outer circumferential surface of the rotor shaft that mates with the stator assembly 2. This shielding layer forms an annular sleeve along the rotor shaft and maintains a certain air gap with the inner shielding sleeve 2b2 of the stator. This air gap ensures the mechanical operating clearance between the rotor and the stator, preventing the rotor from directly contacting the stator when rotating at high speed, while maintaining the normal operating efficiency of the pump.

[0035] The rotor assembly 3 is supported on the fixed structure of the pump body via a bearing support structure. This support can be either a fixed mounting base extending inward from the pump casing 1 or on the end plate 2b3 of the stator assembly 2. This ensures that the rotor remains coaxial and stable during operation. Because the rotor body and the metal shielding layer are rigid structures, they can form a reliable mechanical fit with the stator assembly 2 while maintaining the air gap, achieving overall stable operation.

[0036] Positioning ring 5: A positioning ring 5 is provided between the pump casing 1a and the stator assembly 2. This positioning ring 5 has a hollow structure, which is used to assist in the positioning and fixing of the stator assembly 2 during the assembly process, and also to provide a channel for the liquid medium. The open structure of the positioning ring 5 allows the liquid to flow freely in the pump, while maintaining the assembly accuracy between the stator assembly 2 and the pump casing 1a.

[0037] Flow channel: A liquid medium flow channel is reserved between the shielding sleeve 2b on the outside of the stator assembly 2 and the pump casing 1a. The liquid medium enters the pump body from the inlet on the pump casing end cover 1b, and under the drive of the rotor impeller 4, enters the annular flow channel between the outside of the stator assembly 2 and the pump casing 1a, and then flows along the flow channel to the outlet on the pump casing end cover 1b to be discharged from the pump body. This flow path ensures that the liquid passes smoothly through the pump body, ensures the normal operation of the rotor and stator assembly 2, and avoids the liquid directly impacting the electrical unit 2a in the stator assembly 2, thereby improving the overall safety and stability of the pump body.

[0038] 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.

[0039] 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.

[0040] 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 welded-sealed shielded pump, characterized in that, include: The pump casing (1) includes a pump casing cylinder (1a) and pump casing end caps (1b) disposed at both ends of the pump casing cylinder (1a). The end caps are respectively provided with an inlet and an outlet. The pump casing end caps (1b) and the pump casing cylinder (1a) are sealed by welding with an annular weld. The stator assembly (2) is disposed inside the pump housing (1) and includes an electrical unit (2a) and a shielding sleeve (2b) for sealing the electrical unit (2a). The shielding sleeve (2b) includes an outer support cylinder (2b1), an inner shielding sleeve (2b2), and an end plate (2b3). The inner shielding sleeve (2b2) ​​is fitted inside the outer support cylinder (2b1) to form an annular cylindrical cavity. The two ends of the cavity are sealed by the end plate (2b3) to form a closed cavity. The electrical unit (2a) is disposed in the closed cavity. The end plate (2b3) is welded to the outer support cylinder (2b1) and the inner shielding sleeve (2b2) ​​to form an annular weld seal. The rotor assembly (3) is fitted inside the stator assembly (2), and impellers (4) are installed at both ends of the rotor shaft. A liquid medium flow channel is provided between the shielding sleeve (2b) and the pump casing (1a).

2. The shielded pump according to claim 1, characterized in that, The end plate (2b3) has an annular hole in the middle to form an annular support, and the end of the inner shielding sleeve (2b2) ​​is attached to the hole wall of the annular support.

3. The shielded pump according to claim 2, characterized in that, The end of the inner shielding sleeve (2b2) ​​is welded to the end plate (2b3) at the annular support by an annular weld.

4. The shielded pump according to claim 1, characterized in that, The end of the outer support cylinder (2b1) is pressed against the circumferential surface of the end plate (2b3), and the outer end face of the end plate (2b3) is flush with the outer end face of the outer support cylinder (2b1).

5. The shielded pump according to claim 4, characterized in that, The outer support cylinder (2b1) and the end plate (2b3) are welded together at their end faces to form a circumferential weld.

6. The shielded pump according to claim 1, characterized in that, The end of the pump casing (1a) is pressed against the circumferential surface of the pump casing end cover (1b), and the outer end face of the pump casing end cover (1b) is roughly flush with the outer end face of the pump casing (1a).

7. The shielded pump according to claim 6, characterized in that, The pump casing (1a) and the pump casing end cover (1b) are welded together at their end faces to form an annular weld.

8. The shielded pump according to claim 6, characterized in that, The inner shielding sleeve (2b2) ​​is made of Hastelloy alloy; The end plate (2b3), outer support cylinder (2b1), and pump casing (1) are made of stainless steel, chromium-nickel steel, or nickel-based alloy.

9. The canned pump according to claim 1, characterized in that, A positioning ring (5) is provided between the pump casing (1a) and the stator assembly (2). The positioning ring (5) has a hollow structure for liquid to flow through.

Images