Mechanical sealing mechanism for screw compressor

Abstract

The utility model discloses a mechanical sealing mechanism for a screw compressor. The mechanical sealing mechanism comprises a lip seal, a shaft seal driving sleeve, a transmission sleeve, a moving ring and a static ring, the shaft seal driving sleeve, the transmission sleeve, the moving ring and the static ring are sequentially connected to the outer portion of the rotating shaft in a sleeving mode. The shaft seal driving sleeve is in transmission connection with the rotating shaft through a first transmission pin; the transmission sleeve is in transmission connection with the shaft seal driving sleeve through a second transmission pin; one side of the movable ring is clamped in the transmission sleeve, and the other side of the movable ring is in contact with the static ring; the lip seal is connected outside the shaft seal driving sleeve in a sleeved mode, and a group of annular grooves are formed in the inner wall of the lip seal in the annular direction. The sealing gap is formed between the lip seal and the shaft seal driving sleeve, and the annular groove is formed, so that leakage of lubricating oil from the gap between a sealing structure and a shaft is effectively reduced, the assembling difficulty can be reduced, the lip seal seat and an original lip seal seat can be machined into a whole, and it can be guaranteed that the whole mechanical seal and a main shaft are concentric and do not eccentrically operate.

Description

Technical Field

[0001] The utility model belongs to the technical field of mechanical seals, and in particular relates to a mechanical seal mechanism for a screw compressor. Background Art

[0002] Most twin-screw compressors have a short service life of mechanical seals, and a large amount of oil leakage occurs after a period of operation. A large amount of lubricating oil leakage will cause the unit to shut down, restrict the production load of the enterprise and affect the economic benefits. On the other hand, a large amount of lubricating oil leakage affects the cleanliness of the production plant and increases the workload of the operators. After analyzing the operating conditions of the unit and disassembling the mechanical seal, it was found that the reason for the large amount of oil leakage was that the lip seal in the mechanical seal device was damaged first, resulting in a decrease in the lubricating oil in the sealing chamber, a decrease in the lubrication effect of the friction pair, and the heat generated could not be taken away, resulting in damage to the mechanical seal O-ring, wear of the dynamic and static friction pairs, and leakage. Summary of the invention

[0003] Purpose of the utility model: The technical problem to be solved by the utility model is to provide a mechanical sealing mechanism for a screw compressor in view of the deficiencies in the prior art, so as to solve the problem of large-scale leakage of the mechanical seal of the existing unit in a short period of time and improve the stable operation time of the unit.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0005] A mechanical sealing mechanism for a screw compressor comprises a lip seal, a shaft seal drive sleeve, a transmission sleeve, a dynamic ring and a static ring; the shaft seal drive sleeve, the transmission sleeve, the dynamic ring and the static ring are sleeved on the outside of a rotating shaft in sequence; the shaft seal drive sleeve is transmission-connected to the rotating shaft via a first transmission pin; the transmission sleeve is transmission-connected to the shaft seal drive sleeve via a second transmission pin; one side of the dynamic ring is clamped in the transmission sleeve, and the other side is in contact with the static ring; the lip seal is sleeved on the outside of the shaft seal drive sleeve, and a group of annular grooves are circumferentially provided on the inner wall of the lip seal.

[0006] Furthermore, a gap is left between the lip seal and the shaft seal drive sleeve, and the gap width between the inner wall of the lip seal and the outer wall of the shaft seal drive sleeve is controlled to be 0.20-0.30 mm.

[0007] Furthermore, a group of pressure relief holes are opened on the top of the lip seal, and the diameter of the pressure relief holes is 5-10 mm.

[0008] Preferably, the radius of the annular groove is 1.0-2.0 mm.

[0009] Furthermore, the transmission sleeve is provided with a mounting cavity for clamping the moving ring, and a spring is provided in the mounting cavity, and the clamping depth of the moving ring in the transmission sleeve is adjusted by the spring.

[0010] Furthermore, a push ring is provided in the installation cavity, and the push ring is located between the spring and the moving ring.

[0011] Furthermore, a first O-ring and a retaining ring are provided between the inner wall of the dynamic ring and the rotating shaft.

[0012] Furthermore, a snap ring is provided on the outer side of the inner wall of the installation cavity of the transmission sleeve.

[0013] Specifically, the stationary ring is fixed by screws.

[0014] Furthermore, the outer wall of the static ring is sleeved with a second O-ring. Beneficial Effects

[0015] (1) The utility model provides a sealing gap between the lip seal and the shaft seal driving sleeve and an annular ring groove, thereby effectively reducing the leakage of lubricating oil from the gap between the sealing structure and the shaft, reducing the difficulty of assembly, and can be processed into a whole with the original lip seal seat, thereby ensuring that the entire mechanical seal is concentric with the main shaft and does not operate eccentrically.

[0016] (2) The utility model provides a pressure relief hole at the top of the lip seal, which effectively reduces the risk of increased pressure in the lubrication chamber of the mechanical seal.

[0017] (3) The utility model can effectively reduce the leakage of mechanical seals of compressors. Before using this technology, the leakage reached 60 drops per minute, and the compressor with the maximum leakage could not operate normally. After the modification of the sealing device, the maximum leakage of the units currently in operation is less than 5 drops per minute. Among the four units using the utility model solution, two of them have been running for 120 days and 2800 hours without leakage. At the same time, it effectively reduces the difficulty of installation and makes the installation easier. The original lip seal is often damaged during installation due to improper installation methods and carelessness of maintenance personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods, and the above and / or other advantages of the present invention will become more clear.

[0019] Figure 1 It is a schematic diagram of the working principle of the mechanical sealing mechanism.

[0020] Figure 2 It is a schematic diagram of the overall structure of the mechanical sealing mechanism.

[0021] Figure 3 It is a partial enlarged view of the lip seal and the shaft seal drive sleeve in the mechanical seal mechanism.

[0022] Figure 4It is a component diagram of the lip seal in the mechanical seal mechanism.

[0023] Wherein, each reference numeral represents:

[0024] 100 - rotation axis;

[0025] 1-first transmission pin; 2-lip seal; 201-gap; 202-ring groove; 203-pressure relief hole; 3-shaft seal drive sleeve; 4-second transmission pin; 5-spring; 6-push ring; 7-first O-ring; 8-retaining ring; 9-transmission sleeve; 10-retaining ring; 11-moving ring; 12-static ring; 13-second O-ring; 14-screw. DETAILED DESCRIPTION

[0026] The present invention can be better understood according to the following embodiments.

[0027] The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the utility model, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the utility model, should still fall within the scope of the technical content disclosed by the utility model. At the same time, the terms such as "upper", "lower", "front", "back", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the utility model. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the utility model without substantial change of the technical content.

[0028] Combination Figure 1 and Figure 2 As shown, the mechanical seal mechanism for the screw compressor includes a lip seal 2, a shaft seal drive sleeve 3, a transmission sleeve 9, a dynamic ring 11 and a static ring 12; the shaft seal drive sleeve 3, the transmission sleeve 9, the dynamic ring 11 and the static ring 12 are sequentially sleeved on the outside of the rotating shaft 100; the shaft seal drive sleeve 3 is transmission-connected to the rotating shaft 100 through a first transmission pin 1; the transmission sleeve 9 is transmission-connected to the shaft seal drive sleeve 3 through a second transmission pin 4; one side of the dynamic ring 11 is clamped in the transmission sleeve 9, and the other side is in contact with the static ring 12; the lip seal 2 is sleeved on the outside of the shaft seal drive sleeve 3, and a group of annular grooves 202 are circumferentially provided on the inner wall of the lip seal 2.

[0029] Combination Figure 3 and Figure 4 As shown, in this embodiment, the lip seal 2 is made of 304L material, which can effectively increase the strength. The radius of the annular groove 202 is 1.5 mm.

[0030] In this embodiment, a gap 201 is left between the lip seal 2 and the shaft seal drive sleeve 3, and the width of the gap 201 between the inner wall of the lip seal 2 and the outer wall of the shaft seal drive sleeve 3 is controlled to be 0.25 mm.

[0031] In this embodiment, a group of pressure relief holes 203 are further opened on the top of the lip seal 2, and the diameter of the pressure relief holes 203 is 9 mm.

[0032] Combination Figure 2 The transmission sleeve 9 is provided with an installation cavity for clamping the dynamic ring 11 inside, and a spring 5 is provided in the installation cavity, and the clamping depth of the dynamic ring 11 in the transmission sleeve 9 is adjusted by the spring 5.

[0033] A push ring 6 is also provided in the installation cavity, and the push ring 6 is located between the spring 5 and the moving ring 11 .

[0034] A first O-ring 7 and a retaining ring 8 are provided between the inner wall of the dynamic ring 11 and the rotating shaft 100 .

[0035] A clamping ring 10 is also provided on the outer side of the inner wall of the installation cavity of the transmission sleeve 9 .

[0036] The stationary ring 12 is fixed by screws 14 .

[0037] The outer wall of the static ring 12 is also sleeved with a second O-type sealing ring 13 .

[0038] In this mechanical sealing mechanism, a tiny gap is formed at the junction of the sealing end faces of the dynamic ring 11 and the static ring 12. When the lubricating oil passes through this gap, a very thin liquid film will be formed, generating a resistance, so that the lubricating oil can be sealed in this structure, and the heat generated by the rotation will also be taken away with the flow of the lubricating oil. The rotating shaft 100 and the shaft seal drive sleeve 3 are fixed by transmission pins to make them rotate synchronously. Similarly, the transmission sleeve 9 and the compression spring 5 use transmission pins to make them rotate synchronously with the shaft seal drive sleeve 3. After the spring 5 is assembled, the elastic clamping force generated by the spring 5 and the push ring 6 drives the dynamic ring 11 to rotate synchronously with the above structure coaxially. The elastic clamping force generated by the elastic compensation mechanism composed of the spring 5 as the main body also makes the two sealing end faces of the dynamic ring 11 and the static ring 12 fit tightly to achieve sealing. The retaining ring 10 plays an axial limiting role on the dynamic ring 11. There are four types of seals in this mechanism. The first is the dynamic seal structure formed by the lip seal 2 and the shaft seal drive sleeve 3; the second is the relative seal structure between the dynamic ring 11 and the shaft seal drive sleeve 3; the third is the dynamic seal structure formed by the friction end surface of the dynamic ring 11 and the static ring 12; the fourth is the static seal structure formed between the static ring 13 and the static ring seat. In addition to using special sealing principles at each sealing surface, O-rings are used to achieve sealing. In order to maintain the good sealing effect of the O-ring, it is necessary to ensure that the lubricating oil can flow normally and stably in it to play the role of lubrication and take away friction heat.

[0039] Combination Figure 3 and Figure 4 The sealing principle of the lip seal 2 is to use the internal annular grooves 202 in the integral lip seal 2 to produce a throttling effect when the sealed medium passes through the multiple annular grooves 202, thereby achieving the effect of sealing the lubricating oil. After the annular grooves 202 are opened in the lip seal 2, a series of interception gaps and expansion cavities are formed in the inner ring and the annular grooves, forming a structure similar to a maze. When the lubricating oil passes through the lip seal 2, the hydraulic friction effect generated by the viscosity of the lubricating oil when flowing through the maze and the flow contraction effect form fluid resistance to reduce the flow of the lubricating oil.

[0040] Before using this technology, the leakage of VLG373 twin-screw compressor reached 60 drops per minute, and the compressor with the largest leakage could not operate normally. After the modification of the lip seal device, the maximum leakage of the currently operating unit is less than 5 drops per minute. Among the 4 units using this patented solution, two of them have been running for 120 days and 2800 hours without leakage.

[0041] The utility model provides a concept and method of a mechanical seal mechanism for a screw compressor. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model. These improvements and modifications should also be regarded as the protection scope of the utility model. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A mechanical sealing mechanism for a screw compressor, characterized in that: The invention comprises a lip seal (2), a shaft seal drive sleeve (3), a transmission sleeve (9), a dynamic ring (11) and a static ring (12); the shaft seal drive sleeve (3), the transmission sleeve (9), the dynamic ring (11) and the static ring (12) are sleeved on the outside of a rotating shaft (100) in sequence; the shaft seal drive sleeve (3) is transmission-connected to the rotating shaft (100) via a first transmission pin (1); the transmission sleeve (9) is transmission-connected to the shaft seal drive sleeve (3) via a second transmission pin (4); one side of the dynamic ring (11) is clamped in the transmission sleeve (9), and the other side is in contact with the static ring (12); the lip seal (2) is sleeved on the outside of the shaft seal drive sleeve (3), and a group of annular grooves (202) are circumferentially provided on the inner wall of the lip seal (2).

2. The mechanical seal mechanism for a screw compressor according to claim 1, characterized in that: A gap (201) is left between the lip seal (2) and the shaft seal drive sleeve (3), and the width of the gap (201) between the inner wall of the lip seal (2) and the outer wall of the shaft seal drive sleeve (3) is controlled to be 0.20-0.30 mm.

3. The mechanical seal mechanism for a screw compressor according to claim 1 or 2, characterized in that: A group of pressure relief holes (203) are also formed on the top of the lip seal (2), and the diameter of the pressure relief holes (203) is 5 to 10 mm.

4. The mechanical seal mechanism for a screw compressor according to claim 1 or 2, characterized in that: The radius of the annular groove (202) is 1.0-2.0 mm.

5. The mechanical seal mechanism for a screw compressor according to claim 1 or 2, characterized in that: The transmission sleeve (9) is provided with a mounting cavity for clamping the movable ring (11), and a spring (5) is provided in the mounting cavity, and the clamping depth of the movable ring (11) in the transmission sleeve (9) is adjusted by the spring (5).

6. The mechanical seal mechanism for a screw compressor according to claim 5, characterized in that: A push ring (6) is also provided in the installation cavity, and the push ring (6) is located between the spring (5) and the moving ring (11).

7. The mechanical seal mechanism for a screw compressor according to claim 1 or 2, characterized in that: A first O-type sealing ring (7) and a retaining ring (8) are provided between the inner wall of the dynamic ring (11) and the rotating shaft (100).

8. The mechanical seal mechanism for a screw compressor according to claim 1 or 2, characterized in that: A clamping ring (10) is also provided on the outer side of the inner wall of the installation cavity of the transmission sleeve (9).

9. The mechanical seal mechanism for a screw compressor according to claim 1 or 2, characterized in that: The stationary ring (12) is fixed by means of screws (14).

10. The mechanical seal mechanism for a screw compressor according to claim 1 or 2, characterized in that: The outer wall of the static ring (12) is also sleeved with a second O-type sealing ring (13).

Images