Double-end face seal device for pump capable of eliminating cumulative error and elimination method

Abstract

The present invention relates to the field of fluid machinery technical equipment, specifically referring to a double-end face seal device for pumps capable of eliminating cumulative errors and an elimination method. A double-end face seal device for pumps capable of eliminating cumulative errors includes a pump shaft, a shaft sleeve, a front seal assembly, a rear seal assembly, and a seal gland. An accumulation error elimination mechanism is provided on the shaft sleeve. The accumulation error elimination mechanism includes a transmission fork and a mechanical seal spring. Adjusting gaps are respectively provided between the transmission fork and the front seal assembly and the rear seal assembly. The front seal assembly and the rear seal assembly respectively include a retaining ring, a dynamic ring seat, a dynamic ring, a static ring, and a static ring seat. An elimination method for a double-end face seal device for pumps capable of eliminating cumulative errors is to install the above-mentioned double-end face seal device for pumps capable of eliminating cumulative errors in a housing, and adjust the positions of the shaft sleeve and the transmission fork relative to the front and rear seal assemblies according to the maximum cumulative error in the processing of pump parts. The present invention can eliminate cumulative errors, keep the spring compression amount unchanged, and is convenient for disassembly and assembly.

Description

Technical Field

[0001] The present invention relates to the field of fluid machinery technical equipment, and specifically refers to a double-end face seal device for pumps capable of eliminating cumulative errors and an elimination method thereof. Background Art

[0002] Due to its advantages such as simple structure, convenient disassembly, and low price, the direct-connected chemical pump is widely used in chemical plants. As the application of the direct-connected chemical pump becomes more and more extensive, the transported media are also becoming more and more diverse, including high-temperature, toxic, and harmful media. For transporting dangerous, toxic, and other harmful media, the mechanical seal of the chemical pump must ensure the safety of medium sealing. At present, after the conventional structure of the direct-connected chemical pump is assembled, the tolerance accumulation of the machining dimensions of multiple pump parts has completely exceeded the allowable range, resulting in the spring compression amount of the front and rear sealing surfaces of the double-end face mechanical seal being too tight or too loose. When the conventional direct-connected chemical pump operates, the sealing system is unreliable; in addition, in the prior art, the shaft sleeve and the pump shaft are usually fixedly connected through a locking mechanism, and the installation operation space is narrow, making disassembly and assembly inconvenient. Summary of the Invention

[0003] The purpose of the present invention is to solve the deficiencies of the prior art and provide a double-end face seal device for pumps capable of eliminating cumulative errors and an elimination method thereof, which has a novel structure, can eliminate cumulative errors, has a constant spring compression amount, high safety, and is convenient for disassembly and assembly.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is:

[0005] A double-end face seal device for pumps capable of eliminating cumulative errors, including a pump shaft, a shaft sleeve, a front seal assembly, a rear seal assembly, and a seal gland. The shaft sleeve is fixedly connected to the pump shaft. A front seal assembly and a rear seal assembly are provided between the shaft sleeve and the seal gland. It is characterized in that: an accumulation error elimination mechanism is provided on the shaft sleeve. The accumulation error elimination mechanism includes a transmission fork and a mechanical seal spring. The transmission fork is sleeved on the shaft sleeve and fixedly connected to the shaft sleeve. The transmission fork is located between the front seal assembly and the rear seal assembly. There is an adjustment gap between the front end of the transmission fork and the front seal assembly, and there is an adjustment gap between the rear end of the transmission fork and the rear seal assembly. Spring holes are circumferentially arrayed on the transmission fork, and mechanical seal springs are arranged in the spring holes. One end of each mechanical seal spring passes through the spring hole and abuts against the front seal assembly, and the other end passes through the spring hole and abuts against the rear seal assembly, so as to ensure that when the pump is running, the mechanical seal springs always maintain the initial compression amount through the adjustment gap, neither being too loose nor too tight, and at the same time ensuring that the sealing dimensions of the sealing cavity formed by the shaft sleeve and the seal gland remain unchanged through the adjustment gap.

[0006] The front seal assembly and the rear seal assembly of the present invention respectively include a dynamic seal ring seat, a dynamic seal ring, a static seal ring and a static seal ring seat. An axial front extension is provided with a front drive ring at the front end of the outer wall of the drive fork, and an axial rear extension is provided with a rear drive ring at the rear end of the outer wall of the drive fork. The dynamic seal ring seats are respectively arranged in the front drive ring and the rear drive ring. The dynamic seal ring seat is circumferentially fixedly connected with the front drive ring or the rear drive ring. The dynamic seal ring seat is sleeved on the shaft sleeve and is sealingly connected with the shaft sleeve. An adjusting gap is provided between one end of the dynamic seal ring seat and the drive fork, and a dynamic seal ring is fixedly arranged at the other end. Both ends of the mechanical seal spring respectively pass through the spring holes and abut against the dynamic seal ring seats in the front drive ring and the rear drive ring. The dynamic seal ring abuts against the static seal ring. The dynamic seal ring and the static seal ring are respectively sleeved on the shaft sleeve. The static seal ring is fixedly connected with the seal gland through the static seal ring seat, so as to facilitate the formation of a double-end face seal through the dynamic seal ring, the dynamic seal ring seat, the static seal ring and the static seal ring seat.

[0007] A retaining ring is provided between the dynamic seal ring seat and the drive fork of the present invention. An adjusting gap is provided between one end of the retaining ring and the drive fork, and the other end abuts against the dynamic seal ring seat. The retaining ring is located in the front drive ring or the rear drive ring. The retaining ring is circumferentially fixedly connected with the front drive ring or the rear drive ring. The retaining ring is sleeved on the shaft sleeve and is sealingly connected with the shaft sleeve. Both ends of the mechanical seal spring respectively pass through the spring holes and abut against the retaining rings in the front drive ring and the rear drive ring, so as to further improve the transmission performance and sealing performance through the retaining ring.

[0008] The pump shaft of the present invention is stepped. The pump shaft includes a pump shaft limiting section and a pump shaft connecting section. The pump shaft limiting section is fixedly connected with the pump shaft connecting section. The outer diameter of the pump shaft limiting section is smaller than the outer diameter of the pump shaft connecting section. The shaft sleeve includes a shaft sleeve limiting section and a shaft sleeve connecting section. The shaft sleeve limiting section is fixedly connected with the shaft sleeve connecting section. The inner diameter of the shaft sleeve limiting section is matched with the outer diameter of the pump shaft limiting section. The inner diameter of the shaft sleeve connecting section is matched with the outer diameter of the pump shaft connecting section. The shaft sleeve limiting section is fixedly connected with the pump shaft limiting section through a key, so that when the pump shaft rotates, the water pressure generated by the pump shaft itself makes one end face of the shaft sleeve limiting section facing the shaft sleeve connecting section tightly abut against the end face of the pump shaft connecting section. There is no need for a locking mechanism, and the connection is reliable and stable, and the disassembly and assembly are convenient.

[0009] The seal gland of the present invention includes a mechanical seal box and a mechanical seal cover. The mechanical seal box is fixedly connected with the mechanical seal cover in a sealed manner. The inner wall of the mechanical seal box is connected with the shaft sleeve through the front seal assembly. The inner wall of the mechanical seal cover is connected with the shaft sleeve through the rear seal assembly. Mounting holes are respectively arranged on the outer walls of the mechanical seal box and the mechanical seal cover, so as to facilitate the disassembly and assembly of the pump parts.

[0010] The present invention provides a method for eliminating the cumulative error of a double-end face seal device for pumps, which is characterized in that: the double-end face seal device for pumps capable of eliminating the cumulative error described in claim 4 above is installed in a housing, the mechanical seal box and the mechanical seal gland are respectively fixedly connected to the housing, an impeller is installed at the front end of the pump shaft, and a motor adapter plate is installed at the rear end of the pump shaft. Theoretically, the axial distance between the clamping end face A of the pump shaft and the shaft sleeve and the motor adapter plate is L2, the distance from the mechanical seal box to the motor adapter plate is L3, the adjustment gap between the transmission fork and the front seal assembly is L0, and the adjustment gap between the transmission fork and the rear seal assembly is L1. L1 is equal to L0. When the maximum cumulative error in the processing of pump parts is ΔL, it is set that both L0 and L1 are greater than ΔL. When the cumulative error in the processing of pump parts causes L2 to increase by ΔL, during assembly, the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring and the mechanical seal gland are kept unchanged. At the same time, the shaft sleeve and the transmission fork axially move forward by a distance of ΔL relative to the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring and the mechanical seal gland, so that the distance between the transmission fork and the front seal assembly becomes L0 - ΔL, and the distance between the transmission fork and the rear seal assembly becomes L1 + ΔL. Since both L0 and L1 are greater than ΔL, the compression amount of the mechanical seal spring remains unchanged. Because the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring and the mechanical seal gland are kept unchanged, the distance from the mechanical seal box to the motor adapter plate is still L3, and the influence of the cumulative error is eliminated. When the cumulative error in the processing of pump parts causes L2 to decrease by ΔL, during assembly, the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring and the mechanical seal gland are kept unchanged. At the same time, the shaft sleeve and the transmission fork axially move backward by a distance of ΔL relative to the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring and the mechanical seal gland, so that the distance between the transmission fork and the front seal assembly becomes L0 + ΔL, and the distance between the transmission fork and the rear seal assembly becomes L1 - ΔL. Since both L0 and L1 are greater than ΔL, the compression amount of the mechanical seal spring remains unchanged. Because the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring and the mechanical seal gland are kept unchanged, the distance from the mechanical seal box to the motor adapter plate is still L3, and the influence of the cumulative error is eliminated.

[0011] Due to the above structure, the present invention has the advantages of novel structure, eliminable cumulative error, unchanged spring compression amount, high safety, convenient disassembly and assembly, etc. Brief Description of the Drawings

[0012] Figure 1 It is a schematic structural diagram of the present invention.

[0013] Figure 2 It is a partial schematic structural diagram of the present invention assembled on a pump.

[0014] Reference numerals: pump shaft 1, shaft sleeve 2, front seal assembly 3, rear seal assembly 4, seal gland 5, cumulative error elimination mechanism 6, transmission fork 7, mechanical seal spring 8, retaining ring 9, dynamic ring seat 10, dynamic ring 11, static ring 12, static ring seat 13, front transmission ring 14, rear transmission ring 15, pump shaft limit section 16, pump shaft connection section 17, shaft sleeve limit section 18, shaft sleeve connection section 19, mechanical seal box 20, mechanical seal gland 21, housing 22, impeller 23, motor adapter plate 24. Detailed implementation manners

[0015] The following further describes in detail the specific implementation manners of the present invention in conjunction with the accompanying drawings.

[0016] A double-end face seal device for a pump capable of eliminating cumulative errors, comprising a pump shaft 1, a shaft sleeve 2, a front seal assembly 3, a rear seal assembly 4 and a seal gland 5. The shaft sleeve 2 is fixedly connected to the pump shaft 1. A front seal assembly 3 and a rear seal assembly 4 are provided between the shaft sleeve 2 and the seal gland 5. It is characterized in that a cumulative error elimination mechanism 6 is provided on the shaft sleeve 2. The cumulative error elimination mechanism 6 includes a transmission fork 7 and a mechanical seal spring 8. The transmission fork 7 is sleeved on the shaft sleeve 2 and fixedly connected to the shaft sleeve 2. The transmission fork 7 is located between the front seal assembly 3 and the rear seal assembly 4. An adjustment gap is provided between the front end of the transmission fork 7 and the front seal assembly 3, and an adjustment gap is provided between the rear end of the transmission fork 7 and the rear seal assembly 4. Spring holes are circumferentially arranged on the transmission fork 7, and mechanical seal springs 8 are arranged in the spring holes. One end of the mechanical seal spring 8 passes through the spring hole and abuts against the front seal assembly 3, and the other end passes through the spring hole and abuts against the rear seal assembly 4, so as to ensure that when the pump is running through the adjustment gap, the mechanical seal spring always maintains the initial compression amount, neither too loose nor too tight, and at the same time, the sealing dimension of the sealing cavity formed by the shaft sleeve and the seal gland is ensured to be unchanged through the adjustment gap.

[0017] The front seal assembly 3 and the rear seal assembly 4 of the present invention respectively include a dynamic ring seat 10, a dynamic ring 11, a static ring 12 and a static ring seat 13. Anterior drive rings 14 axially extend forward at the front end of the outer wall of the drive fork 7, and posterior drive rings 15 axially extend backward at the rear end of the outer wall of the drive fork 7. The dynamic ring seats 10 are respectively arranged inside the anterior drive rings 14 and the posterior drive rings 15. The dynamic ring seat 10 is circumferentially fixedly connected to the anterior drive ring 14 or the posterior drive ring 11, which is conducive to driving the dynamic ring seat to rotate through the drive fork. At the same time, when the fork axially moves, the dynamic ring seat can remain stationary. The dynamic ring seat 10 is sleeved on the shaft sleeve 2 and is sealingly connected to the shaft sleeve 2. There is an adjustment gap between one end of the dynamic ring seat 10 and the drive fork 7, and a dynamic ring 11 is fixedly arranged at the other end. Both ends of the mechanical seal spring 8 respectively pass through the spring holes and abut against the dynamic ring seat 10 inside the anterior drive ring 14 and the dynamic ring seat 10 inside the posterior drive ring 11. The dynamic ring 11 abuts against the static ring 12. The dynamic ring 11 and the static ring 12 are respectively sleeved on the shaft sleeve 2. The static ring 12 is sealingly and fixedly connected to the sealing gland 5 through the static ring seat 13, which is conducive to forming a double-end face seal through the dynamic ring, the dynamic ring seat, the static ring and the static ring seat.

[0018] A retaining ring 9 is arranged between the dynamic ring seat 10 and the drive fork 7 of the present invention. There is an adjustment gap between one end of the retaining ring 9 and the drive fork 7, and the other end abuts against the dynamic ring seat 10. The retaining ring 9 is located inside the anterior drive ring 14 or the posterior drive ring 15. The retaining ring 9 is circumferentially fixedly connected to the anterior drive ring 14 or the posterior drive ring 15, which is conducive to driving the retaining ring to rotate through the drive fork. At the same time, when the fork axially moves, the retaining ring can remain stationary. The retaining ring 9 is sleeved on the shaft sleeve 2 and is sealingly connected to the shaft sleeve 2. Both ends of the mechanical seal spring 8 respectively pass through the spring holes and abut against the retaining ring 9 inside the anterior drive ring 14 and the retaining ring 9 inside the posterior drive ring 11, which is conducive to further improving the transmission performance and sealing performance through the retaining ring.

[0019] The pump shaft 1 of the present invention is stepped. The pump shaft 1 includes a pump shaft limiting section 16 and a pump shaft connecting section 17. The pump shaft limiting section 16 is fixedly connected to the pump shaft connecting section 17. The outer diameter of the pump shaft limiting section 16 is smaller than that of the pump shaft connecting section 17. The shaft sleeve 2 includes a shaft sleeve limiting section 18 and a shaft sleeve connecting section 19. The shaft sleeve limiting section 18 is fixedly connected to the shaft sleeve connecting section 19. The inner diameter of the shaft sleeve limiting section 18 is matched with the outer diameter of the pump shaft limiting section 16, and the inner diameter of the shaft sleeve connecting section 19 is matched with the outer diameter of the pump shaft connecting section 17. The shaft sleeve limiting section 18 is fixedly connected to the pump shaft limiting section 16 through a key, which is conducive to when the pump shaft rotates, making the end face of one end of the shaft sleeve limiting section facing the shaft sleeve connecting section tightly abut against the end face of the pump shaft connecting section through the water pressure generated by the pump shaft itself. Without a locking mechanism, the connection is reliable and stable, and the disassembly and assembly are convenient.

[0020] The seal gland 5 of the present invention includes a mechanical seal box 20 and a mechanical seal gland 21. The mechanical seal box 20 is hermetically and fixedly connected to the mechanical seal gland 21. The inner wall of the mechanical seal box 20 is connected to the shaft sleeve 2 through a front seal assembly 3, and the inner wall of the mechanical seal gland 21 is connected to the shaft sleeve 2 through a rear seal assembly 4. Mounting holes are respectively provided on the outer walls of the mechanical seal box 20 and the mechanical seal gland 21 to facilitate the disassembly and assembly of pump parts.

[0021] The present invention provides a method for eliminating the accumulated error of a double-end face seal device for a pump. The method is characterized in that: the double-end face seal device for a pump capable of eliminating the accumulated error described above is installed in a housing 22. The mechanical seal box 20 and the mechanical seal gland 21 are respectively fixedly connected to the housing 22. An impeller 23 is installed at the front end of the pump shaft 1, and a motor adapter plate 24 is installed at the rear end of the pump shaft 1. Theoretically, the axial distance between the clamping end face A of the pump shaft 1 and the shaft sleeve 2 and the motor adapter plate 24 is L2, and the distance from the mechanical seal box 20 to the motor adapter plate 24 is L3. The adjustment gap between the transmission fork 7 and the retaining ring 9 of the front seal assembly 3 is L0, and the adjustment gap between the transmission fork 7 and the retaining ring 9 of the rear seal assembly 4 is L1. L1 is equal to L0. When the maximum accumulated error in the processing of pump parts is ΔL, it is set that both L0 and L1 are greater than ΔL. When the accumulated error in the processing of pump parts causes L2 to increase by ΔL, during assembly, the positions of the mechanical seal box 20, the front seal assembly 3, the rear seal assembly 4, the mechanical seal spring 8, and the mechanical seal gland 21 are kept unchanged. At the same time, the shaft sleeve 2 and the transmission fork 7 axially move forward by a distance of ΔL relative to the mechanical seal box 20, the front seal assembly 3, the rear seal assembly 4, the mechanical seal spring 8, and the mechanical seal gland 21, so that the distance between the transmission fork 7 and the retaining ring 9 of the front seal assembly 3 becomes L0 - ΔL, and the distance between the transmission fork 7 and the retaining ring 9 of the rear seal assembly 4 becomes L1 + ΔL. Since both L0 and L1 are greater than ΔL, the compression amount of the mechanical seal spring 8 remains unchanged. Because the positions of the mechanical seal box 20, the front seal assembly 3, the rear seal assembly 4, the mechanical seal spring 8, and the mechanical seal gland 21 are kept unchanged, the distance from the mechanical seal box 20 to the motor adapter plate 24 is still L3, and the influence of the accumulated error is eliminated. When the accumulated error in the processing of pump parts causes L2 to decrease by ΔL, during assembly, the positions of the mechanical seal box 20, the front seal assembly 3, the rear seal assembly 4, the mechanical seal spring 8, and the mechanical seal gland 21 are kept unchanged. At the same time, the shaft sleeve 2 and the transmission fork 7 axially move backward by a distance of ΔL relative to the mechanical seal box 20, the front seal assembly 3, the rear seal assembly 4, the mechanical seal spring 8, and the mechanical seal gland 21, so that the distance between the transmission fork 7 and the retaining ring 9 of the front seal assembly 3 becomes L0 + ΔL, and the distance between the transmission fork 7 and the retaining ring 9 of the rear seal assembly 4 becomes L1 - ΔL. Since both L0 and L1 are greater than ΔL, the compression amount of the mechanical seal spring 8 remains unchanged. Because the positions of the mechanical seal box 20, the front seal assembly 3, the rear seal assembly 4, the mechanical seal spring 8, and the mechanical seal gland 21 are kept unchanged, the distance from the mechanical seal box 20 to the motor adapter plate 24 is still L3, and the influence of the accumulated error is eliminated.

[0022] As shown in the appendix Figure 1 , in the present invention, a mechanical seal cavity is formed between the mechanical seal box, the mechanical seal gland and the shaft sleeve. As shown in the appendix Figure 2 is a partial structural schematic diagram when the present invention is used and installed on a chemical pump. During assembly, the front seal assembly and the rear seal assembly are installed on the shaft sleeve. The dynamic ring and the dynamic ring seat rotate with the shaft sleeve, while the static ring and the static ring seat do not rotate with the shaft sleeve. The dynamic ring and the static ring form a friction pair. A mechanical seal spring is installed in the spring hole of the transmission fork, and then the transmission fork is fixed to the shaft sleeve by screws. At the same time, the front transmission ring of the transmission fork sleeves on the retaining ring of the front seal assembly and part of the dynamic ring seat to drive the retaining ring and the dynamic ring seat to rotate with the shaft sleeve. The rear transmission ring of the transmission fork sleeves on the retaining ring of the rear seal assembly and part of the dynamic ring seat to drive the retaining ring and the dynamic ring seat to rotate with the shaft sleeve. The static ring seat of the front seal assembly is fixedly connected to the mechanical seal box in a sealed manner. The static ring seat of the rear seal assembly is fixedly connected to the mechanical seal gland in a sealed manner. The mechanical seal box is fixedly connected to the mechanical seal gland. The above structure is installed on the pump shaft as a whole. During installation, the keyway of the shaft sleeve faces the key on the pump shaft, and the whole is pushed towards the motor end until the end face of the limiting section of the shaft sleeve facing one end of the shaft sleeve connection section tightly abuts against the end face of the pump shaft connection section. An impeller is installed at one end of the pump shaft, and a motor adapter plate is installed at the other end. The pump shaft is driven by the motor. The housing includes a pump body and a pump cover. The pump body is fixedly connected to the pump cover. The front end of the impeller is connected to the pump body through a front stuffing box and a wear-resistant ring. The rear end of the impeller is connected to the pump cover through a rear stuffing box and a wear-resistant ring. The pump body and the pump cover are fixedly connected to each other in a sealed manner. The connection relationship between the motor, the motor bracket, the pump body, the pump cover, and the motor adapter plate is the same as that in the prior art and will not be elaborated

[0023] As shown in the appendix Figure 1 , theoretically, after the pump is assembled, the size of the mechanical seal cavity formed by the mechanical seal box, the mechanical seal gland and the shaft sleeve is L. The axial distance between the clamping end face A of the pump shaft and the shaft sleeve and the motor adapter plate is L2, and the distance from the mechanical seal box to the motor adapter plate is L3. However, during the processing, the tolerance accumulation of the machining dimensions of multiple pump parts will generate an error of ΔL. If no adjustment is made, it will change the compression amount of the spring, resulting in the spring being too loose or too tight and affecting the sealing performance. To solve the above problems, in the present invention, a transmission fork is arranged on the shaft sleeve. The transmission fork is fixed to the shaft sleeve by screws. A mechanical seal spring is arranged on the transmission fork. There is an adjustment gap L0 between the transmission fork and the front seal assembly, and an adjustment gap L1 between the transmission fork and the rear seal assembly. L0 is equal to L1. The gaps of L0 and L1 can be set according to the maximum accumulated error. If the maximum accumulated error in machining is ΔL, then both L0 and L1 are set to be greater than ΔL. The numerical range of L0 and L1 in the present invention is: 3 - 5 mm

[0024] The adjustment method of the present invention during assembly is as follows:

[0025] First, when ΔL is positive, the cumulative error causes L2 to increase by ΔL. During assembly, the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland are kept unchanged. At the same time, the shaft sleeve and the transmission fork move axially forward by a distance of ΔL relative to the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland, making the distance between the transmission fork and the front seal assembly become L0 - ΔL, and the distance between the transmission fork and the rear seal assembly become L1 + ΔL. Since both L0 and L1 are greater than ΔL, the compression amount of the mechanical seal spring remains unchanged. Because the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland are kept unchanged, the distance from the mechanical seal box to the motor adapter plate is still L3, and the size of the mechanical seal cavity composed of the mechanical seal box, the mechanical seal gland, and the shaft sleeve also remains unchanged, still being L, eliminating the influence of the cumulative error. Second, when ΔL is negative, the cumulative error causes L2 to decrease by ΔL. During assembly, the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland are kept unchanged. At the same time, the shaft sleeve and the transmission fork move axially backward by a distance of ΔL relative to the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland, making the distance between the transmission fork and the front seal assembly become L0 + ΔL, and the distance between the transmission fork and the rear seal assembly become L1 - ΔL. Since both L0 and L1 are greater than ΔL, the compression amount of the mechanical seal spring remains unchanged. Because the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland are kept unchanged, the distance from the mechanical seal box to the motor adapter plate is still L3, and the size of the mechanical seal cavity composed of the mechanical seal box, the mechanical seal gland, and the shaft sleeve also remains unchanged, still being L, eliminating the influence of the cumulative error. In this way, the cumulative error generated during the machining of the pump parts is eliminated during the assembly process. When the pump is running, the spring compression amount remains unchanged, the double-end face sealing performance is good, and when the pump is running, the shaft sleeve rotates with the pump shaft through the key, the shaft sleeve drives the transmission fork to rotate, and at the same time, the shaft sleeve is pressed tightly by the liquid pressure P generated by the pump itself, as shown in the appendix Figure 1 , making it axially and reliably fit together with the pump shaft without an additional locking mechanism, solving the disadvantages of the narrow installation operation space and difficult disassembly of the conventional direct-coupled pump, and the operation is fast and convenient.

[0026] Due to the adoption of the above structure, the present invention has the advantages of novel structure, eliminable cumulative error, unchanged spring compression amount, high safety, convenient disassembly and assembly, etc.

Claims

1. A method for eliminating the accumulated error of a double-ended face seal device for pumps, characterized in that: Including a double mechanical seal device for a pump that can eliminate cumulative errors, the double mechanical seal device for a pump that can eliminate cumulative errors includes a pump shaft, a shaft sleeve, a front seal assembly, a rear seal assembly, and a seal gland. The shaft sleeve is fixedly connected to the pump shaft. There are a front seal assembly and a rear seal assembly between the shaft sleeve and the seal gland. It is characterized in that: an accumulation error elimination mechanism is provided on the shaft sleeve. The accumulation error elimination mechanism includes a transmission fork and a mechanical seal spring. The transmission fork is sleeved on the shaft sleeve and fixedly connected to the shaft sleeve. The transmission fork is located between the front seal assembly and the rear seal assembly. There is an adjustment gap between the front end of the transmission fork and the front seal assembly, and there is an adjustment gap between the rear end of the transmission fork and the rear seal assembly. Spring holes are circumferentially arrayed on the transmission fork, and mechanical seal springs are arranged in the spring holes. One end of the mechanical seal spring passes through the spring hole and abuts against the front seal assembly, and the other end passes through the spring hole and abuts against the rear seal assembly. The pump shaft is stepped. The pump shaft includes a pump shaft limiting section and a pump shaft connecting section. The pump shaft limiting section is fixedly connected to the pump shaft connecting section. The outer diameter of the pump shaft limiting section is smaller than the outer diameter of the pump shaft connecting section. The shaft sleeve includes a shaft sleeve limiting section and a shaft sleeve connecting section. The shaft sleeve limiting section is fixedly connected to the shaft sleeve connecting section. The inner diameter of the shaft sleeve limiting section is matched with the outer diameter of the pump shaft limiting section, and the inner diameter of the shaft sleeve connecting section is matched with the outer diameter of the pump shaft connecting section. The shaft sleeve limiting section is fixedly connected to the pump shaft limiting section through a key. The seal gland includes a mechanical seal box and a mechanical seal gland. The mechanical seal box is hermetically and fixedly connected to the mechanical seal gland. The inner wall of the mechanical seal box is connected to the shaft sleeve through the front seal assembly, and the inner wall of the mechanical seal gland is connected to the shaft sleeve through the rear seal assembly. Mounting holes are respectively provided on the outer walls of the mechanical seal box and the mechanical seal gland. The double mechanical seal device for a pump that can eliminate cumulative errors is installed in a housing. The mechanical seal box and the mechanical seal gland are respectively fixedly connected to the housing. An impeller is installed at the front end of the pump shaft, and a motor adapter plate is installed at the rear end of the pump shaft. Theoretically, the axial distance between the clamping end face A of the pump shaft and the shaft sleeve and the motor adapter plate is L2, and the distance from the mechanical seal box to the motor adapter plate is L3. The adjustment gap between the transmission fork and the front seal assembly is L0, and the adjustment gap between the transmission fork and the rear seal assembly is L1. L1 is equal to L0. When the maximum cumulative error in the processing of pump parts is ΔL, it is set that both L0 and L1 are greater than ΔL. When the cumulative error in the processing of pump parts causes L2 to increase by ΔL, during assembly, the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland are kept unchanged. At the same time, the shaft sleeve and the transmission fork axially move forward by a distance of ΔL relative to the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland, so that the distance between the transmission fork and the front seal assembly becomes L0 - ΔL, and the distance between the transmission fork and the rear seal assembly becomes L1 + ΔL. Since both L0 and L1 are greater than ΔL, the compression amount of the mechanical seal spring remains unchanged. Because the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland are kept unchanged, the distance from the mechanical seal box to the motor adapter plate is still L3, eliminating the influence of the cumulative error;When the cumulative error in the machining of pump parts causes L2 to decrease by ΔL, during assembly, the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland are kept unchanged. At the same time, the shaft sleeve and the transmission fork move axially backward by a distance of ΔL relative to the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland, so that the distance between the transmission fork and the front seal assembly becomes L0 + ΔL, and the distance between the transmission fork and the rear seal assembly becomes L1 - ΔL. Since both L0 and L1 are greater than ΔL, the compression amount of the mechanical seal spring remains unchanged. Because the positions of the mechanical seal box, the front seal assembly, the rear seal assembly, the mechanical seal spring, and the mechanical seal gland are kept unchanged, the distance from the mechanical seal box to the motor adapter plate is still L3, eliminating the influence of the cumulative error.

2. The elimination method of the double-ended face seal device for pumps capable of eliminating cumulative errors according to claim 1, characterized in that: The front seal assembly and the rear seal assembly respectively include a moving ring seat, a moving ring, a stationary ring and a stationary ring seat. A front drive ring axially extends forward at the front end of the outer wall of the transmission fork, and a rear drive ring axially extends backward at the rear end of the outer wall of the transmission fork. Moving ring seats are respectively arranged inside the front drive ring and the rear drive ring. The moving ring seat is circumferentially fixedly connected to the front drive ring or the rear drive ring. The moving ring seat is sleeved on the shaft sleeve and is sealingly connected to the shaft sleeve. An adjusting gap is provided between one end of the moving ring seat and the transmission fork, and a moving ring is fixedly provided at the other end. Both ends of the mechanical seal spring respectively pass through the spring holes and abut against the moving ring seats inside the front drive ring and the rear drive ring. The moving ring abuts against the stationary ring. The moving ring and the stationary ring are respectively sleeved on the shaft sleeve. The stationary ring is fixedly connected to the sealing gland through the stationary ring seat in a sealed manner.

3. The elimination method of the double-ended face seal device for pumps capable of eliminating cumulative errors according to claim 2, characterized in that: A retaining ring is provided between the moving ring seat and the transmission fork. An adjusting gap is provided between one end of the retaining ring and the transmission fork, and the other end abuts against the moving ring seat. The retaining ring is located inside the front drive ring or the rear drive ring. The retaining ring is circumferentially fixedly connected to the front drive ring or the rear drive ring. The retaining ring is sleeved on the shaft sleeve and is sealingly connected to the shaft sleeve. Both ends of the mechanical seal spring respectively pass through the spring holes and abut against the retaining rings inside the front drive ring and the rear drive ring.

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