New mechanical seal arrangement structure and submersible pump using the same

Abstract

The novel mechanical seal arrangement structure includes a motor shaft, a motor end cover, and an oil chamber cover. An oil isolation chamber is formed between the oil chamber cover and the motor end cover. The motor shaft passes through the motor end cover and the oil chamber cover. Mechanical seals A and B are installed on the motor shaft. The static ring A is installed in the static ring groove A of the motor end cover, and the dynamic ring A forms a seal with the motor shaft. A spring and a sleeve are also installed on the motor shaft. One end of the spring abuts against the end face of the dynamic ring A, and the other end of the spring abuts against the end face of one end of the sleeve. The end face of the other end of the sleeve is fixed on the hub of the impeller. The static ring B is installed in the static ring groove B of the oil chamber cover. A rubber bellows for sealing and positioning is provided between the dynamic ring B and the sleeve. The inner diameter of the static ring B is larger than the outer diameter of the dynamic ring A, and the upper end face of the static ring B is located above the lower end face of the dynamic ring A. The arrangement structure of the present invention has the advantages of large liquid sealing pressure, short axial dimension, high reliability and easy installation and maintenance. Correspondingly, the present invention also provides a submersible pump adopting the structure.

Description

Technical Field

[0001] The invention relates to a submersible pump technology, in particular to a novel mechanical seal arrangement structure and a submersible pump adopting the structure. Background Art

[0002] At present, two sets of mechanical seals (machine seals) are often used between the motor and the water pump to match the sealing structure of the oil isolation chamber to prevent water from entering the motor, as shown in the patent with the publication number CN214063310U; the layout design between the two sets of mechanical seals is usually divided into two types: 1) back-to-back double-end face seal arrangement; 2) independent machine seal series arrangement. The back-to-back double-end face seal arrangement has the advantages of short axial dimension and simple structure; but there are the disadvantages of low sealing pressure, mutual interference between the operating states of the two sealing surfaces, and problems with one sealing surface will also occur with the other sealing surface, and there are the disadvantages of low sealing reliability. It is only suitable for small low-lift submersible pumps, not large high-lift submersible pumps. The independent machine seal series arrangement has the advantages of high sealing pressure and high reliability; but it also has the disadvantages of long axial dimension and shaft slotting; the elongated shaft leads to low shaft rigidity, large impeller shaking, serious wear of the mouth ring, and frequent replacement of parts; at the same time, the shaft slotting will also cause inconvenience in installation and maintenance. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a new mechanical seal arrangement structure, which has the advantages of high liquid sealing pressure, short axial dimension, high reliability and easy installation and maintenance; correspondingly, the present invention also provides a submersible pump adopting the new mechanical seal arrangement structure, which has the advantages of small size, reliable operation and easy installation and maintenance.

[0004] For the arrangement structure, the technical solution of the present invention is as follows:

[0005] The novel mechanical seal arrangement structure comprises a motor shaft, a motor end cover and an oil chamber cover, wherein the oil chamber cover is mounted on the motor end cover, an oil isolation chamber is formed between the oil chamber cover and the motor end cover, the motor shaft passes through the motor end cover and the oil chamber cover, a mechanical seal A and a mechanical seal B are mounted on the motor shaft; the mechanical seal A comprises a stationary ring A and a dynamic ring A, and the mechanical seal B comprises a stationary ring B and a dynamic ring B; the stationary ring A is mounted in a stationary ring groove A of the motor end cover, and the dynamic ring A forms a seal with the motor shaft; a spring and a bushing are also mounted on the motor shaft, one end of the spring abuts against the end face of the dynamic ring A, and the spring is used to provide the dynamic ring A with Motion compensation and transmission of rotational torque, the other end of the spring is against the end face of one end of the sleeve, and the end face of the other end of the sleeve is fixed on the hub of the impeller; the static ring B is installed in the static ring groove B of the oil chamber cover, and the outer ring surface of the sleeve is located in the inner ring surface of the dynamic ring B; a rubber bellows for sealing and positioning is provided between the dynamic ring B and the sleeve, one end of the rubber bellows contacts with the end face of the dynamic ring B and forms a seal, and the other end of the rubber bellows contacts with the limit end face on the sleeve and forms a seal; the inner diameter of the static ring B is larger than the outer diameter of the dynamic ring A, and the upper end face of the static ring B is located above the lower end face of the dynamic ring A.

[0006] The novel mechanical seal arrangement structure provided by the present invention has the advantages of large liquid sealing pressure, short axial dimension, high reliability and easy installation and maintenance, which are specifically manifested as follows: the two sets of mechanical seals provided by the present invention are arranged in series, which is a built-in installation, and the liquid sealing pressure is higher than the sealing pressure when the back-to-back double-end face seals are arranged, and the mechanical seal is in a self-tightening working mode during operation, and the pressure between the sealing surfaces of the mechanical seal will increase synchronously with the increase of the liquid sealing pressure, thereby ensuring the reliability of the seal; at the same time, in the mechanical seal arrangement structure of the present invention, the axial installation positions of the mechanical seal A and the mechanical seal B are staggered by the action of the shaft sleeve, There is an overlapping part in the axial dimensions of the two sets of mechanical seals, so that the axial length dimension is not only smaller than the independent mechanical seals arranged in series in the prior art, but also smaller than the back-to-back double-end face seal arrangement; in addition, compared with the existing independent mechanical seals arranged in series, the axial length of the mechanical seal in the mechanical seal arrangement structure of the present invention is shortened, so that the length of the motor shaft is also shortened, avoiding the problems of low shaft rigidity, large impeller shaking and severe wear caused by the elongation of the motor shaft, and the reliability is further improved; finally, because the two sets of mechanical seals are axially positioned by the shaft sleeve, there is no need to open the groove for mechanical seal positioning on the motor shaft, which is easy to install and maintain the mechanical seal.

[0007] As an optimization, in the aforementioned new mechanical seal arrangement structure, the lubricating oil in the oil isolation chamber occupies more than 90% of the space. The presence of the lubricating oil can not only cool and lubricate the mechanical seal, but also play an isolation effect between the pump and the motor.

[0008] As an optimization, in the aforementioned new mechanical seal arrangement structure, an O-ring is provided between the moving ring A and the motor shaft, and an O-ring is provided between the shaft sleeve and the motor shaft. After the moving ring A, the shaft sleeve and the motor shaft are sealed with the O-ring, a static seal can be formed between the moving ring A, the shaft sleeve and the motor shaft.

[0009] As an optimization, in the aforementioned new mechanical seal arrangement structure, an O-ring or a sealing cup is provided between the static ring A and the motor end cover. After the static ring A and the motor end cover are sealed with the O-ring or the sealing cup, a static seal can be formed between the static ring A and the motor end cover.

[0010] As an optimization, in the aforementioned new mechanical seal arrangement structure, an O-ring or a sealing cup is provided between the static ring B and the oil chamber cover. After the static ring B and the oil chamber cover are sealed with an O-ring or a sealing cup, a static seal can be formed between the static ring B and the oil chamber cover. Furthermore, a rubber cup is provided between the static ring B and the oil chamber cover, the rubber cup is installed in the static ring groove B of the oil chamber cover, and the static ring B is installed in the rubber cup. The contact area of ​​the rubber cup is large, and the rubber cup is used to seal between the static ring B and the oil chamber cover, which can fully ensure the sealing effect.

[0011] As an optimization, in the aforementioned new mechanical seal arrangement structure, the shaft sleeve and the impeller hub end face are each provided with two sockets, cylindrical pins are installed in the sockets, and the shaft sleeve is fixed to the impeller hub end face by the two cylindrical pins. After the shaft sleeve is fixed to the impeller hub end face by the two cylindrical pins, the impeller can drive the shaft sleeve to rotate, and then drive the mechanical seal A and the mechanical seal B to rotate.

[0012] For the submersible pump, the technical solution of the present invention is as follows:

[0013] The submersible pump adopts the aforementioned new mechanical seal arrangement structure.

[0014] The submersible pump adopting the novel mechanical seal arrangement structure provided by the present invention has the advantages of small size, reliable operation and easy installation and maintenance, which are specifically manifested as follows: since the axial length of the mechanical seal in the mechanical seal arrangement structure of the present invention is shortened, the length of the motor shaft is also shortened, the axial size of the motor is smaller, and the volume of the submersible pump is reduced; at the same time, since the mechanical seal arrangement structure of the present invention avoids the problems of low shaft rigidity, large impeller shaking and severe wear caused by the elongation of the motor shaft, the operation of the submersible pump is reliable; finally, since the two sets of mechanical seals are axially positioned by the shaft sleeve, there is no need to open the groove for mechanical seal positioning on the motor shaft, which is easy to install and maintain later.

[0015] As an optimization, in the aforementioned submersible pump adopting the novel mechanical seal arrangement structure, the shaft sleeve is a casting or a stainless steel sheet rolled part, which has a low production cost.

[0016] As an optimization, in the aforementioned submersible pump adopting the new mechanical seal arrangement structure, the impeller of the submersible pump adopts a double-suction impeller. The double-suction impeller has a large flow rate, high working efficiency, and stable operation during the working process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a submersible pump adopting a novel mechanical seal arrangement structure of the present invention;

[0018] Figure 2 for Figure 1 The enlarged image in the middle circle A;

[0019] The markings in the attached drawings are: 1-motor shaft; 2-motor end cover, 201-stationary ring groove A; 3-oil chamber cover, 301-stationary ring groove B; 4-oil isolation chamber; 5-mechanical seal A, 501-stationary ring A, 502-dynamic ring A; 6-mechanical seal B, 601-stationary ring B, 602-dynamic ring B; 7-spring; 8-shaft sleeve, 801-limiting end face; 9-impeller; 10-rubber bellows; 11-rubber leather cup; 12-motor casing; 13-cylindrical pin. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods (including examples), but they are not intended to limit the present invention.

[0021] See also Figure 1-2The novel mechanical seal arrangement structure of the present invention comprises a motor shaft 1, a motor end cover 2 and an oil chamber cover 3, wherein the oil chamber cover 3 is mounted on the motor end cover 2, an oil isolation chamber 4 is formed between the oil chamber cover 3 and the motor end cover 2, the motor shaft 1 passes through the motor end cover 2 and the oil chamber cover 3, a mechanical seal A5 and a mechanical seal B6 are mounted on the motor shaft 1; the mechanical seal A5 comprises a stationary ring A501 and a dynamic ring A502, the mechanical seal B6 comprises a stationary ring B601 and a dynamic ring B602; the stationary ring A501 is mounted in the stationary ring groove A201 of the motor end cover 2, the dynamic ring A502 forms a seal with the motor shaft 1; a spring 7 and a bushing 8 are also mounted on the motor shaft 1, one end of the spring 7 is connected to the end of the dynamic ring A502 The surfaces of the two shaft sleeves are abutted against each other, and the other end of the spring 7 is abutted against the end face of one end of the sleeve 8, and the end face of the other end of the sleeve 8 is fixed on the hub of the impeller 9; the static ring B601 is installed in the static ring groove B301 of the oil chamber cover 3, and the outer ring surface of the sleeve 8 is located in the inner ring surface of the dynamic ring B602; a rubber bellows 10 for sealing and positioning is provided between the dynamic ring B602 and the sleeve 8, one end of the rubber bellows 10 contacts with the end face of the dynamic ring B602 and forms a seal, and the other end of the rubber bellows 10 contacts with the limit end face 801 on the sleeve 8 and forms a seal; the inner diameter of the static ring B601 is larger than the outer diameter of the dynamic ring A502, and the upper end face of the static ring B601 is located above the lower end face of the dynamic ring A502.

[0022] During operation, two sets of mechanical seals are arranged in series, and the sleeve 8 is fixed on the hub of the impeller 9; since one end of the spring 7 abuts against the end face of the moving ring A502, and the other end of the spring 7 abuts against the end face of one end of the sleeve 8, and the mechanical seal A5 is fixed in the static ring groove A201, the spring 7 can provide motion compensation and transfer rotational torque to the moving ring A502 during the process of the impeller 9 driving the sleeve 8 to rotate, so that the moving ring A502 rotates relative to the static ring A501. At the same time, since the moving ring B602 and the sleeve 8 are sealed and positioned by the rubber bellows 10, the mechanical seal B6 can be fixed in the static ring groove B301, so that the moving ring B602 rotates relative to the static ring B601 during the process of the impeller 9 driving the sleeve 8 to rotate. During the entire working process, the mechanical seal B6 forms the first seal to prevent the water delivered by the pump from entering the oil isolation chamber 4; the oil isolation chamber 4 forms a buffer zone, which can not only lubricate and cool the mechanical seal, but also absorb a small amount of water leaked from the first seal; the mechanical seal A5 forms the second seal, thereby preventing oil or oil-water mixture from entering the inner cavity of the motor.

[0023] The sealing arrangement structure of the present invention can achieve a liquid sealing pressure of 1.0 MPa, which is higher than the 0.2-0.25 MPa of the back-to-back double-end face sealing arrangement; compared with the existing independent mechanical seal series arrangement, in the sealing arrangement structure of the present invention, the axial dimension of the motor shaft 1 can be shortened by 15-16% when the diameter of the motor shaft 1 is in the range of 20-40 mm.

[0024] Example:

[0025] In this embodiment, the lubricating oil occupies 95% of the space in the oil isolation chamber 4. The presence of the lubricating oil can not only cool and lubricate the mechanical seal, but also play an isolation effect between the pump and the motor.

[0026] In this embodiment, an O-ring is provided between the moving ring A502 and the motor shaft 1, and an O-ring is provided between the shaft sleeve 8 and the motor shaft 1. After the moving ring A502, the shaft sleeve 8 and the motor shaft 1 are sealed with the O-ring, a static seal can be formed between the moving ring A502, the shaft sleeve 8 and the motor shaft 1.

[0027] In this embodiment, an O-ring is provided between the static ring A501 and the motor end cover 2. After the static ring A501 and the motor end cover 2 are sealed by the O-ring, a static seal can be formed between the static ring A501 and the motor end cover 2.

[0028] In this embodiment, a rubber cup 11 is provided between the stationary ring B601 and the oil chamber cover 3, the rubber cup 11 is installed in the stationary ring groove B301 of the oil chamber cover 3, and the stationary ring B601 is installed in the rubber cup 11. After the stationary ring B601 and the oil chamber cover 3 are sealed by the rubber cup 11, a static seal can be formed between the stationary ring B601 and the oil chamber cover 3, and the contact area of ​​the rubber cup 11 is large, which can fully ensure the sealing effect.

[0029] In this embodiment, two insertion holes are respectively provided on the hub end face of the sleeve 8 and the impeller 9, and cylindrical pins 13 are installed in the insertion holes, and the sleeve 8 is fixed to the hub end face of the impeller 9 through the two cylindrical pins 13. After the sleeve 8 is fixed to the hub end face of the impeller 9 through the two cylindrical pins 13, the impeller 9 can drive the sleeve 8 to rotate, and then drive the mechanical seal A5 and the mechanical seal B6 to rotate.

[0030] In this embodiment, see Figure 1-2 The submersible pump of the present invention is equipped with the novel mechanical seal arrangement structure of the present embodiment; further, the shaft sleeve 8 is made of a stainless steel sheet rolled part, and the production cost of the stainless steel sheet rolled part is low; further, the impeller 9 of the submersible pump is a double-suction impeller, which has a large flow rate, high working efficiency, and runs smoothly during operation.

[0031] The above description of "upper" and "lower" in this application is relative to Figure 1 This is only for the orientation in the figure and should not be understood as a limitation on the technical solution of the invention.

[0032] The above general description of the invention involved in this application and the description of its specific implementation methods should not be understood as limiting the technical solutions of the invention. Based on the disclosure of this application, those skilled in the art can add, reduce or combine the disclosed technical features in the above general description and / or specific implementation methods (including examples) without violating the constituent elements of the invention involved, to form other technical solutions within the scope of protection of this application.

Claims

1. New mechanical seal arrangement structure, characterized by: The invention comprises a motor shaft (1), a motor end cover (2) and an oil chamber cover (3), wherein the oil chamber cover (3) is mounted on the motor end cover (2), an oil isolation chamber (4) is formed between the oil chamber cover (3) and the motor end cover (2), the motor shaft (1) passes through the motor end cover (2) and the oil chamber cover (3), and a mechanical seal A (5) and a mechanical seal B (6) are mounted on the motor shaft (1); the mechanical seal A (5) comprises a stationary ring A (501) and a dynamic ring A (502), and the mechanical seal B (6) comprises a stationary ring B (601) and a dynamic ring B (602); the stationary ring A (501) is mounted in a stationary ring groove A (201) of the motor end cover (2), and the dynamic ring A (502) forms a seal with the motor shaft (1); a spring (7) and a shaft sleeve (8) are also mounted on the motor shaft (1), and one end of the spring (7) is in contact with the dynamic ring A (502). The end surface of the spring (7) abuts against the end surface of one end of the shaft sleeve (8), and the end surface of the other end of the shaft sleeve (8) is fixed to the hub of the impeller (9); the stationary ring B (601) is installed in the stationary ring groove B (301) of the oil chamber cover (3), and the outer ring surface of the shaft sleeve (8) is located in the inner ring surface of the dynamic ring B (602); a sealing and positioning member is provided between the dynamic ring B (602) and the shaft sleeve (8). A rubber bellows (10), one end of the rubber bellows (10) contacts the end face of the dynamic ring B (602) to form a seal, and the other end of the rubber bellows (10) contacts the limit end face (801) on the shaft sleeve (8) to form a seal; the inner diameter of the static ring B (601) is greater than the outer diameter of the dynamic ring A (502), and the upper end face of the static ring B (601) is located above the lower end face of the dynamic ring A (502).

2. The novel mechanical seal arrangement structure according to claim 1 is characterized in that: The lubricating oil occupies more than 90% of the space in the oil isolation chamber (4).

3. The novel mechanical seal arrangement structure according to claim 1 is characterized in that: An O-type sealing ring is provided between the dynamic ring A (502) and the motor shaft (1), and an O-type sealing ring is provided between the shaft sleeve (8) and the motor shaft (1).

4. The novel mechanical seal arrangement structure according to claim 1 is characterized in that: An O-ring or a sealing cup is provided between the static ring A (501) and the motor end cover (2).

5. The novel mechanical seal arrangement structure according to claim 1 is characterized in that: An O-ring or a sealing leather cup is provided between the stationary ring B (601) and the oil chamber cover (3).

6. The novel mechanical seal arrangement structure according to claim 5 is characterized in that: A rubber cup (11) is provided between the stationary ring B (601) and the oil chamber cover (3); the rubber cup (11) is installed in the stationary ring groove B (301) of the oil chamber cover (3); and the stationary ring B (601) is installed in the rubber cup (11).

7. The novel mechanical seal arrangement structure according to claim 1 is characterized in that: The shaft sleeve (8) and the hub end face of the impeller (9) are each provided with two insertion holes, cylindrical pins (13) are installed in the insertion holes, and the shaft sleeve (8) is fixed to the hub end face of the impeller (9) through the two cylindrical pins (13).

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