A containerized plastic mechanical seal with an internal structure

Abstract

The present invention relates to the technical field of mechanical seals for liquid pumps, and specifically discloses a cartridge-type plastic mechanical seal with an internal installation structure; it includes a main shaft sleeve, a water seal ring, a medium-end seal assembly, a water seal assembly, and a main shaft. The main shaft is arranged in the main shaft sleeve. The water seal ring is fixedly sleeved on the main shaft sleeve. A spoiler shaft sleeve is arranged on the main shaft close to the medium-end seal assembly. A number of serrated spoiler fans are arranged on the spoiler shaft sleeve. The inner end of the spoiler shaft sleeve extends into the medium-end seal assembly and the main shaft sleeve. A sliding sealing ring is arranged on the outer circumferential surface of the spoiler shaft sleeve. By providing the spoiler shaft sleeve, the present invention can effectively disperse and disturb the solid particles at the medium end, so that the solid particles will not deposit at the dynamic ring, and the dynamic ring will not be stuck by the particles, greatly extending the service life. And through the sliding of the spoiler shaft sleeve, the spring is always in the best compression state, which will not cause excessive compression damage to the spring, and greatly extends the service life.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical seals for liquid pumps, and specifically discloses a cartridge-type plastic mechanical seal with an internal installation structure. Background Art

[0002] In various rotary pumps for conveying fluid media, in order to prevent the fluid media from leaking out along the gap between the pump casing and the high-speed rotating pump shaft, a mechanical seal is usually provided between the pump casing and the pump shaft. A cartridge-type mechanical seal is a seal formed by assembling main components such as a dynamic ring, a static ring, a spring, an auxiliary sealing ring, a shaft sleeve, a gland, and a static sealing gasket together at a non-maintenance site.

[0003] Currently, the cartridge-type plastic mechanical seals cited on the market for various rotary pumps all have some deficiencies. For example, the invention patent with the application number 2014106166570 discloses a cartridge-type mechanical seal device for a corrosion-resistant pump. The device is composed of a shaft sleeve, a gland, a medium-side seal located inside the gland, and an atmosphere-side water seal located outside the gland. A wave spring is installed between the spring seat and the gland; the medium-side seal further includes an anti-lock sealing ring and an anti-lock sealing gasket. Another example is the invention patent with the application number 2019210378772, which discloses a structure of a fluoroplastic centrifugal pump with a cartridge-type mechanical seal device, including a mechanical seal seat assembly, a shaft sleeve, and a mechanical seal assembly. The mechanical seal assembly is installed between the mechanical seal seat assembly and the shaft sleeve. The mechanical seal assembly includes a dynamic ring seat, a front dynamic ring, and a rear dynamic ring. The dynamic ring seat is fixedly connected to the shaft sleeve. Ring grooves are provided at both the front and rear ends of the dynamic ring seat. The front dynamic ring and the rear dynamic ring are respectively installed in the two ring grooves. Sealing gaskets are installed between the front dynamic ring, the rear dynamic ring and the shaft sleeve. A butting spring is installed between the front dynamic ring and the rear dynamic ring on the dynamic ring seat; a front static ring is closely installed on the inner wall of the front part of the mechanical seal seat assembly, and a rear static ring is closely installed on the inner wall of the rear part of the mechanical seal seat assembly. The front end face of the front dynamic ring is sealingly attached to the rear end face of the front static ring, and the rear end face of the rear dynamic ring is sealingly attached to the front end face of the rear static ring.

[0004] The cartridge-type mechanical seals disclosed in the above two inventions have three important deficiencies: First, there is no non-metallic material at the part of the existing internal-mounted cartridge seal that contacts the liquid, and acidic substances cannot be transported. Although plastic anti-corrosion linings are provided in both documents, the overall strength of the mechanical seal cannot be satisfied; Second, the existing internal-mounted cartridge seal does not have a flow-disturbing shaft sleeve. When the particulate matter at the medium end accumulates at the position of the static ring, it will cause wear of the ring surface and reduce the service life of the entire cartridge-type mechanical seal; Third, the existing cartridge-type mechanical

[0005] The end face dimensions of the seal are the dimensions for mating with the main machine. Only when the dimensions for mating with the main machine are equal to the end face dimensions, the spring of the mechanical seal is in the best compression state. However, there are tolerances in the dimensions for mating with the main machine. When the tolerance exceeds a certain value, the end face dimensions will become larger or smaller accordingly, resulting in abnormal compression of the spring and reducing the service life of the mechanical seal. Therefore, in view of the above deficiencies of the existing assembled plastic mechanical seal, the present invention proposes an assembled plastic mechanical seal with an internal structure that can effectively solve the above technical problems. Summary of the Invention

[0006] The object of the present invention is to design an assembled plastic mechanical seal with an internal structure to solve the above three technical problems in view of the three deficiencies mentioned in the background art existing in the existing assembled plastic mechanical seal.

[0007] The present invention is achieved through the following technical solutions:

[0008] An assembled plastic mechanical seal with an internal structure, including a main shaft sleeve, a water seal ring, a medium-end seal assembly, a water seal assembly, and a main shaft. The main shaft is arranged in the main shaft sleeve. The water seal ring is fixedly sleeved on the main shaft sleeve. The medium-end seal assembly is installed on the end of the main shaft sleeve close to the medium end. The water seal assembly is installed on the end of the main shaft sleeve close to the atmosphere end. A turbulence shaft sleeve is arranged on the main shaft close to the medium-end seal assembly. A plurality of serrated turbulence fans are arranged on the outer circumferential surface of the outer end of the turbulence shaft sleeve. The inner end of the turbulence shaft sleeve extends into the medium-end seal assembly and the main shaft sleeve. Two sliding sealing rings are arranged on the outer circular surface of the turbulence shaft sleeve, and the sliding sealing rings are in contact with the inner circumferential wall of the medium-end seal assembly.

[0009] As a specific setting of the above solution, the medium-end seal assembly includes a dynamic ring and a static ring. A dynamic ring seat is connected to the end of the main shaft sleeve close to the medium end. The dynamic ring is arranged in the dynamic ring seat. Dynamic ring sealing rings are arranged between the outer circular surface of the dynamic ring and the inner wall of the dynamic ring seat, and between the inner wall of the dynamic ring and the outer circular surface of the main shaft sleeve. A static seal cavity is arranged on the end face of the water seal ring. The static ring is arranged between the inner wall of the static seal cavity and the outer circular surface of the main shaft sleeve, and a static ring sealing ring is arranged between the outer circular surface of the static ring and the inner wall of the static seal cavity.

[0010] As a specific setting of the above solution, the static seal cavity and the water seal ring are integrally injection-molded, and the static seal cavity is injection-molded with wear-resistant plastic. The water seal ring is integrally machined from stainless steel, so that the water seal ring does not directly contact the medium-end liquid, but the static seal cavity contacts the liquid.

[0011] As a specific setting of the above solution, the main shaft sleeve and the moving ring seat are integrally injection-molded. The moving ring seat is injection-molded with wear-resistant plastic, and the main shaft sleeve is integrally machined from stainless steel, so that the main shaft sleeve does not directly contact the liquid at the medium end, but the moving ring seat contacts the liquid.

[0012] As a specific setting of the above solution, the water seal assembly includes a water seal static ring seat and a water seal moving ring seat. The water seal static ring seat is arranged between the inner wall of the water seal ring and the outer circular surface of the main shaft sleeve. The water seal moving ring seat is sleeved on the end of the main shaft sleeve close to the atmosphere end, and a water seal static ring and a water seal moving ring are arranged between the inner walls of the water seal static ring seat and the water seal moving ring seat.

[0013] As a further setting of the above solution, a positioning retaining ring is arranged between the outer circular surface of the water seal ring and the outer circular surface of the water seal moving ring seat, and a tightening ring is arranged on the outer circular surface of the positioning retaining ring.

[0014] As a specific setting of the above solution, a water seal static ring seal is arranged between the outer circular surface of the water seal static ring seat and the inner wall of the water seal ring, and a water seal moving ring seal is arranged between the inner wall of the water seal moving ring seat and the outer circular surface of the main shaft sleeve.

[0015] As a specific setting of the above solution, a spring member is arranged between the inner end of the static ring and the inner end of the water seal static ring seat.

[0016] As a specific setting of the above solution, the spring member adopts a double-row spring design, one row of springs is connected to the static ring, and the other row of springs is connected to the water seal static ring seat.

[0017] As a specific setting of the above solution, a first shaft sleeve seal is arranged on the side of the turbulence shaft sleeve facing the medium end, and a second shaft sleeve seal is arranged on the inner wall of the main shaft sleeve.

[0018] Beneficial effects:

[0019] 1) In the present invention, a turbulence shaft sleeve is added to the main shaft at the medium end. The edge of the turbulence shaft sleeve has 6-8 serrated turbulence fans, which can effectively disperse and disturb the solid particles at the medium end, so that the solid particles will not deposit at the moving ring, and the moving ring will not be stuck by the particles, greatly extending the service life.

[0020] 2) There are two sliding seals on the turbulence shaft sleeve of the present invention, and the main shaft sleeve can slide on the turbulence shaft sleeve; when the end face size cannot be precise, the tolerance of the end face size can be compensated by the sliding of the main shaft sleeve, so that the spring is always in the best compression state, and it will not cause excessive compression damage of the spring, greatly extending the service life.

[0021] 3) The shaft sleeve and the water seal ring at the liquid-contact part in the mechanical seal disclosed by the present invention are designed into two parts. One part is composed of plastic parts, and the other part still provides the overall strength with metal parts, so that it not only meets the ability to transport acidic substances, but also meets the overall strength of the mechanical seal.

[0022] 4) The spring part in the mechanical seal disclosed by the present invention adopts a double-row spring design. One row of springs compensates one stationary ring. When the water seal stationary ring is worn due to water cut-off and the spring is damaged, it will not affect the compensation performance of the other row of springs. The stationary ring and the moving ring at the medium end can still seal the liquid, providing double protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 is the front view internal plane structure schematic diagram of the present invention;

[0025] Figure 2 is the plane structure schematic diagram of the main shaft sleeve in the present invention;

[0026] Figure 3 is the plane structure schematic diagram of the spoiler shaft sleeve in the present invention;

[0027] Figure 4 is the plane structure schematic diagram of the medium-end seal assembly in the present invention;

[0028] Figure 5 is the plane structure schematic diagram of the water seal ring and the static seal cavity in the present invention;

[0029] Figure 6 is the plane structure schematic diagram of the water seal assembly in the present invention.

[0030] Wherein:

[0031] 1 - main shaft sleeve, 101 - second shaft sleeve sealing ring;

[0032] 2 - water seal ring, 201 - static seal cavity;

[0033] 3 - medium-end seal assembly, 301 - moving ring, 302 - stationary ring, 303 - moving ring seat, 304 - moving ring sealing ring, 305 - stationary ring sealing ring;

[0034] 4 - Water seal sealing assembly, 401 - Water seal static ring seat, 402 - Water seal dynamic ring seat, 403 - Water seal static ring, 404 - Water seal dynamic ring, 405 - Positioning retaining ring, 406 - Tightening ring;

[0035] 5 - Main shaft;

[0036] 6 - Turbulence shaft sleeve, 601 - Serrated turbulence fan, 602 - Sliding sealing ring, 603 - First shaft sleeve sealing ring;

[0037] 7 - Spring part. Detailed implementation manner

[0038] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0039] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will refer to the attached Figures 1 to 6 drawings and describe this application in detail in combination with the embodiments.

[0040] Embodiment 1

[0041] Embodiment 1 discloses a built-in type assembled plastic mechanical seal. Referring to the attached Figure 1 drawings, the left side in the drawings is the medium end, and the right side is the atmosphere end. The main part of this mechanical seal respectively includes a main shaft sleeve 1, a water seal ring 2, a medium end sealing assembly 3, a water seal sealing assembly 4, and a main shaft 5. The main shaft 5 is arranged in the main shaft sleeve 1, the water seal ring 2 is fixedly sleeved on the main shaft sleeve 1, and the medium end sealing assembly 3 is installed on the end of the main shaft sleeve 1 close to the medium end.

[0042] Specifically, this medium end sealing assembly 3 includes a dynamic ring 301 and a static ring 302. A dynamic ring seat 303 is connected to the end of the main shaft sleeve 1 close to the medium end. The dynamic ring 301 is arranged in the dynamic ring seat 303. Dynamic ring seals 304 are arranged between the outer circumferential surface of the dynamic ring 301 and the inner wall of the dynamic ring seat 303, and between the inner wall of the dynamic ring 301 and the outer circumferential surface of the main shaft sleeve 1. A static seal cavity 201 is arranged on the end face of the water seal ring 2. The static ring 302 is arranged between the inner wall of the static seal cavity 201 and the outer circumferential surface of the main shaft sleeve 1, and a static ring seal 305 is arranged between the outer circumferential surface of the static ring 302 and the inner wall of the static seal cavity 201.

[0043] In this Embodiment 1, the static seal cavity 201 and the water seal ring 2 are integrally injection-molded. The static seal cavity 201 is injection-molded with wear-resistant plastic, and the water seal ring 2 is integrally machined from stainless steel. Similarly, the main shaft sleeve 1 and the dynamic ring seat 303 are integrally injection-molded. The dynamic ring seat 303 is injection-molded with wear-resistant plastic, and the main shaft sleeve 1 is integrally machined from stainless steel. Through the above setting method, the shaft sleeve and the water seal ring at the liquid-contact part of this mechanical seal are designed into two parts. One part is composed of plastic parts, and the other part still provides the overall strength with metal parts. This not only meets the ability to transport acidic substances but also meets the overall strength of the mechanical seal.

[0044] Refer to the appendix Figure 1 , the water seal assembly 4 is installed on the end of the main shaft sleeve 1 near the atmosphere end. When specifically set, the water seal assembly 4 includes a water seal static ring seat 401 and a water seal dynamic ring seat 402. The water seal static ring seat 401 is arranged between the inner wall of the water seal ring 2 and the outer circular surface of the main shaft sleeve 1. The water seal dynamic ring seat 402 is sleeved on the end of the main shaft sleeve 1 near the atmosphere end, and a water seal static ring 403 and a water seal dynamic ring 404 are arranged between the inner walls of the water seal static ring seat 401 and the water seal dynamic ring seat 402. In order to stably install the water seal dynamic ring seat 402, a positioning retaining ring 405 is also arranged between the outer circular surface of the water seal ring 2 and the water seal dynamic ring seat 402, and a tightening ring 406 is arranged on the outer circular surface of the positioning retaining ring 405. At the same time, in order to ensure its installation sealing performance, a water seal static ring seal 407 is also arranged between the outer circular surface of the water seal static ring seat 401 and the inner wall of the water seal ring 2, and a water seal dynamic ring seal 408 is arranged between the inner wall of the water seal dynamic ring seat 402 and the outer circular surface of the main shaft sleeve 1.

[0045] Finally, a spring member 7 is arranged between the inner end of the static ring 302 and the inner end of the water seal static ring seat 401. The spring member 7 adopts a double-row spring design. One row of springs is connected to the static ring 302, and the other row of springs is connected to the water seal static ring seat 401. By adopting the double-row spring design above, one row of springs compensates one side of the static ring. When the water seal static ring is worn due to water cut-off and the spring is damaged, it will not affect the compensation performance of the other row of springs. The static ring and the dynamic ring at the medium end can still seal the liquid, providing double protection.

[0046] Embodiment 2

[0047] Embodiment 2 discloses an assembled plastic mechanical seal with an improved internal structure based on Embodiment 1. Refer to the appendix Figure 1 , the main body part of this mechanical seal respectively includes a main shaft sleeve 1, a water seal ring 2, a medium-end seal assembly 3, a water seal assembly 4, and a main shaft 5. The main shaft 5 is arranged in the main shaft sleeve 1, the water seal ring 2 is fixedly sleeved on the main shaft sleeve 1, and the medium-end seal assembly 3 is installed on the end of the main shaft sleeve 1 near the medium end.

[0048] During specific setting, the medium-end seal assembly 3 includes a dynamic seal ring 301 and a static seal ring 302. A dynamic seal ring seat 303 is connected to the end of the main shaft sleeve 1 near the medium end. The dynamic seal ring 301 is arranged in the dynamic seal ring seat 303. Dynamic seal rings 304 are arranged between the outer circular surface of the dynamic seal ring 301 and the inner wall of the dynamic seal ring seat 303, and between the inner wall of the dynamic seal ring 301 and the outer circular surface of the main shaft sleeve 1. A static seal cavity 201 is arranged on the end face of the water seal ring 2. The static seal ring 302 is arranged between the inner wall of the static seal cavity 201 and the outer circular surface of the main shaft sleeve 1, and a static seal ring 305 is arranged between the outer circular surface of the static seal ring 302 and the inner wall of the static seal cavity 201.

[0049] In this Embodiment 2, the static seal cavity 201 and the water seal ring 2 are integrally injection-molded, and the static seal cavity 201 is injection-molded with wear-resistant plastic, while the water seal ring 2 is integrally machined from stainless steel. Similarly, the main shaft sleeve 1 and the dynamic seal ring seat 303 are integrally injection-molded, and the dynamic seal ring seat 303 is injection-molded with wear-resistant plastic, while the main shaft sleeve 1 is integrally machined from stainless steel. Through the above setting method, the shaft sleeve and the water seal ring at the part in contact with the liquid of this mechanical seal are designed into two parts, one part is composed of plastic parts, and the other part still provides the overall strength with metal parts. It not only meets the ability to transport acidic substances but also meets the overall strength of the mechanical seal.

[0050] Refer to the appendix Figure 1 The water seal assembly 4 is installed on the end of the main shaft sleeve 1 near the atmosphere end. During specific setting, the water seal assembly 4 includes a water seal static ring seat 401 and a water seal dynamic ring seat 402. The water seal static ring seat 401 is arranged between the inner wall of the water seal ring 2 and the outer circular surface of the main shaft sleeve 1. The water seal dynamic ring seat 402 is sleeved on the end of the main shaft sleeve 1 near the atmosphere end, and a water seal static ring 403 and a water seal dynamic ring 404 are arranged between the inner walls of the water seal static ring seat 401 and the water seal dynamic ring seat 402. In order to stably install the water seal dynamic ring seat 402, a positioning retaining ring 405 is also arranged between the outer circular surface of the water seal ring 2 and the outer circular surface of the water seal dynamic ring seat 402, and a tightening ring 406 is arranged on the outer circular surface of the positioning retaining ring 405. At the same time, in order to ensure its installation sealing performance, a water seal static ring seal 407 is also arranged between the outer circular surface of the water seal static ring seat 401 and the inner wall of the water seal ring 2, and a water seal dynamic ring seal 408 is arranged between the inner wall of the water seal dynamic ring seat 402 and the outer circular surface of the main shaft sleeve 1.

[0051] A spring member 7 is arranged between the inner end of the static seal ring 302 and the inner end of the water seal static ring seat 401. The spring member 7 adopts a double-row spring design, where one row of springs is connected to the static seal ring 302 and the other row of springs is connected to the water seal static ring seat 401. By adopting the above double-row spring design, one row of springs compensates for one static seal ring. When the water seal static ring is worn due to water cut-off and the spring is damaged, it will not affect the compensation performance of the other row of springs, and the static seal ring and the dynamic seal ring at the medium end can still seal the liquid, providing double protection.

[0052] In addition, with reference to the attached Figure 1 drawing and the attached Figure 3 , in the second embodiment, a spoiler bushing 6 is further provided on the main shaft 5 near the medium end sealing assembly 3. A plurality of serrated spoiler fans 601 are provided on the outer circumferential surface of the outer end of the spoiler bushing 6. Specifically, 6-8 serrated spoiler fans 601 can be provided. The inner end of the spoiler bushing 6 extends into the medium end sealing assembly 3 and the main shaft sleeve 1. Two sliding sealing rings 602 are provided on the outer circumferential surface of the spoiler bushing 6, and the sliding sealing rings 602 are arranged in contact with the inner circumferential wall of the medium end sealing assembly 3. Finally, a first shaft sleeve sealing ring 603 is provided on the side surface of the spoiler bushing 6 facing the medium end, and a second shaft sleeve sealing ring 101 is provided on the inner wall of the main shaft sleeve 1

[0053] After adding the spoiler bushing to the improved mechanical seal in the second embodiment, turbulence is generated at the position of the spoiler bushing. The particulate matter can be scattered and agitated by the 6-8 serrated spoiler fans around the spoiler bushing, and the particulate matter will not deposit. At the same time, after adding the spoiler bushing and the sliding sealing ring, the shaft sleeve can slide back and forth on the sliding sealing ring of the spoiler bushing, changing the end face size, so that the spring is in the optimal working state, and the service life of the mechanical seal and the main machine is improved.

[0054] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A containerized plastic mechanical seal with an internal structure, comprising a main shaft sleeve (1), a water seal ring (2), a medium-end seal assembly (3), a water seal assembly (4), and a main shaft (5). The main shaft (5) is arranged in the main shaft sleeve (1), the water seal ring (2) is fixedly sleeved on the main shaft sleeve (1), the medium-end seal assembly (3) is installed on the end of the main shaft sleeve (1) near the medium end, and the water seal assembly (4) is installed on the end of the main shaft sleeve (1) near the atmosphere end. It is characterized in that, A spoiler sleeve (6) is provided on the main shaft (5) near the medium-end sealing assembly (3). A number of serrated spoiler fans (601) are provided on the outer circumferential surface of the outer end of the spoiler sleeve (6). The inner end of the spoiler sleeve (6) extends into the medium-end sealing assembly (3) and the main shaft sleeve (1). Two sliding sealing rings (602) are provided on the outer circumferential surface of the spoiler sleeve (6), and the sliding sealing rings (602) are in contact with the inner circumferential wall of the medium-end sealing assembly (3); the medium-end sealing assembly (3) includes a moving ring (301) and a static ring (302). A moving ring seat (303) is connected to the end of the main shaft sleeve (1) near the medium end. The moving ring (301) is arranged in the moving ring seat (303). Dynamic ring seals (304) are provided between the outer circumferential surface of the moving ring (301) and the inner wall of the moving ring seat (303), and between the inner wall of the moving ring (301) and the outer circumferential surface of the main shaft sleeve (1). A static seal cavity (201) is provided on the end face of the water seal ring (2). The static ring (302) is arranged between the inner wall of the static seal cavity (201) and the outer circumferential surface of the main shaft sleeve (1), and a static ring seal (305) is provided between the outer circumferential surface of the static ring (302) and the inner wall of the static seal cavity (201); the static seal cavity (201) and the water seal ring (2) are integrally injection-molded, and the static seal cavity (201) is injection-molded with wear-resistant plastic, and the water seal ring (2) is integrally machined from stainless steel; the main shaft sleeve (1) and the moving ring seat (303) are integrally injection-molded, and the moving ring seat (303) is injection-molded with wear-resistant plastic, and the main shaft sleeve (1) is integrally machined from stainless steel.

2. The assembled plastic mechanical seal with an internal structure according to claim 1, characterized in that: The water seal sealing assembly (4) includes a water seal static ring seat (401) and a water seal moving ring seat (402). The water seal static ring seat (401) is arranged between the inner wall of the water seal ring (2) and the outer circumferential surface of the main shaft sleeve (1). The water seal moving ring seat (402) is sleeved on the end of the main shaft sleeve (1) near the atmosphere end, and a water seal static ring (403) and a water seal moving ring (404) are provided between the inner walls of the water seal static ring seat (401) and the water seal moving ring seat (402).

3. The assembled plastic mechanical seal with an internal structure according to claim 2, characterized in that: A positioning retaining ring (405) is provided between the outer circumferential surface of the water seal ring (2) and the outer circumferential surface of the water seal moving ring seat (402), and a tightening ring (406) is provided on the outer circumferential surface of the positioning retaining ring (405).

4. The integrated plastic mechanical seal with an internal structure according to claim 3, characterized in that: A water seal static ring seal (407) is provided between the outer circumferential surface of the water seal static ring seat (401) and the inner wall of the water seal ring (2), and a water seal moving ring seal (408) is provided between the inner wall of the water seal moving ring seat (402) and the outer circumferential surface of the main shaft sleeve (1).

5. The assembled plastic mechanical seal with an internal structure according to claim 4, characterized in that: A spring member (7) is provided between the inner end of the static ring (302) and the inner end of the water seal static ring seat (401).

6. The assembled plastic mechanical seal with an internal structure according to claim 5, characterized in that: The spring member (7) adopts a double-row spring design, with one row of springs connected to the static ring (302) and the other row of springs connected to the water seal static ring seat (401).

7. The assembled plastic mechanical seal with an internal structure according to claim 6, characterized in that: A first shaft sleeve seal (603) is provided on the side of the spoiler sleeve (6) facing the medium end, and a second shaft sleeve seal (101) is provided on the inner wall of the main shaft sleeve (1).

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