Mechanical seal with pressure adjustable function

Abstract

The present invention discloses a mechanical seal with a pressure adjustable function, comprising: a shaft sleeve, two sealing dynamic rings, two sealing static rings, a sealing sleeve and an axial force adjusting pre-tightening nut. An elastic ring is sleeved outside the shaft sleeve. The sealing dynamic ring is circumferentially fixed to the shaft sleeve; the two sealing dynamic rings are respectively elastically abutted against opposite sides of the elastic ring. The two sealing dynamic rings are located between the two sealing static rings and respectively axially press one of the sealing static rings. The sealing sleeve is sleeved outside the sealing dynamic ring, and both ends of the sealing sleeve are respectively abutted against one of the sealing static rings; an external thread is provided at one end of the sealing sleeve, and a first air hole is provided on the sealing sleeve; the axial force adjusting pre-tightening nut is provided with an internal thread, and the internal thread is in threaded cooperation with the external thread; the axial force adjusting pre-tightening nut has a pressing part, and the pressing part is connected to and presses one end of one of the sealing static rings and is used to drive the sealing static ring to press the sealing dynamic ring. It can adjust the pressure between the sealing static ring and the sealing dynamic ring so that the pressure between the two is moderate.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical seals, and particularly to a mechanical seal with a pressure adjustable function. Background Art

[0002] The existing shaft end mechanical seal structures mainly include labyrinth seal, packing seal, and face friction seal; mainly, high-pressure gas is injected into the inner cavity of the mechanical seal to prevent the materials in the material cavity from entering the inner cavity of the mechanical seal. Since the pressure between the stationary seal ring and the rotating seal ring of the labyrinth seal is small, the gas leakage is large, so that the high-pressure gas in the mechanical seal needs to be continuously blown into the material cavity. And the high-pressure gas may carry dust, so the labyrinth seal is not suitable for the food industry. Although the face friction seal is suitable for the food industry, the pressure between its stationary seal ring and rotating seal ring is large, resulting in problems that the debris generated by friction is difficult to handle, and the excessive axial pressure will also cause overheating due to friction, thus aggravating the wear of the mechanical seal, that is, reducing the service life of the mechanical seal. Summary of the Invention

[0003] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a mechanical seal with a pressure adjustable function, which can adjust the pressure between the stationary seal ring and the rotating seal ring, so that the pressure between them is moderate, making it not only suitable for the food industry but also free from a series of drawbacks such as excessive friction.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] A mechanical seal with a pressure adjustable function includes:

[0006] A shaft sleeve for sleeving on a rotating shaft; an elastic ring is sleeved outside the shaft sleeve;

[0007] Two rotating seal rings are sleeved outside the shaft sleeve and are circumferentially fixed to the shaft sleeve; the two rotating seal rings are respectively elastically abutted against opposite sides of the elastic ring;

[0008] Two stationary seal rings are sleeved outside the shaft sleeve; the two rotating seal rings are located between the two stationary seal rings and respectively axially press one of the stationary seal rings;

[0009] A seal sleeve is sleeved outside the rotating seal rings, and both ends of the seal sleeve are respectively abutted against one of the stationary seal rings, so that the two rotating seal rings, the two stationary seal rings, and the seal sleeve together enclose a positive pressure air cavity; an external thread is provided at one end of the seal sleeve, and the seal sleeve is provided with a first air hole communicating with the positive pressure air cavity;

[0010] Axial force-adjusting pre-tightening nut, which is provided with an internal thread, and the internal thread is in threaded fit with the external thread; the axial force-adjusting pre-tightening nut has an extrusion part, and the extrusion part is extruded and connected to one end of one of the static sealing rings and is used to drive the static sealing ring to extrude the dynamic sealing ring.

[0011] Furthermore, the axial force-adjusting pre-tightening nut is provided with a radial gap, and the radial gap is recessed radially from the outside curved surface wall of the axial force-adjusting pre-tightening nut from outside to inside, so that reaction force supporting parts and deformation parts are respectively formed on opposite sides of the axial force-adjusting pre-tightening nut where the radial gap is located. The reaction force supporting part is provided with a threaded through hole, and a self-locking screw is threadedly connected to the threaded through hole. The self-locking screw extends into the radial gap and can extrude the deformation part to expand the outer edge width of the radial gap.

[0012] Furthermore, both of the static sealing rings are fixedly connected to the sealing sleeve.

[0013] Furthermore, the static sealing ring far from the axial force-adjusting pre-tightening nut is circumferentially fixedly connected to the sealing sleeve through an axial screw.

[0014] Furthermore, the static sealing ring close to the axial force-adjusting pre-tightening nut is provided with a radial threaded hole, and the sealing sleeve is provided with a radial installation groove. A circumferential stop screw is connected to the radial threaded hole, and the head of the circumferential stop screw is accommodated in the radial installation groove, so that the sealing sleeve and the static sealing ring close to the axial force-adjusting pre-tightening nut are circumferentially fixed together.

[0015] Furthermore, a limiting ring is formed by the outer curved surface wall of the shaft sleeve protruding radially from inside to outside. The two dynamic sealing rings are respectively located on opposite sides of the limiting ring, and the elastic ring is sleeved outside the limiting ring.

[0016] Furthermore, the sealing sleeve is also provided with a second air hole communicating with the positive pressure air cavity. The first air hole is used for air intake, and the second air hole is used for air exhaust.

[0017] Furthermore, a end plate is fixedly connected to the static sealing ring far from the axial force-adjusting pre-tightening nut. The end plate is used to be fixed to the material box and support the static sealing ring.

[0018] Furthermore, the inner curved surface wall of the static sealing ring far from the axial force-adjusting pre-tightening nut is in a conical structure, and the small end of the conical structure is closer to the dynamic sealing ring than the large end of the conical structure.

[0019] Furthermore, a sealing shaft ring is embedded at one end of the shaft sleeve. The sealing shaft ring is used to press the rotating shaft in an interference fit manner and axially limit the shaft sleeve; a radial fixing screw is connected to the end of the shaft sleeve far from the sealing shaft ring.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] By pre-adjusting or real-time adjusting the axial force-adjusting pre-tightening nut, the pressing part forces the end of the static sealing ring connected by extrusion, so that the distance between the two static sealing rings is reduced, that is, the distance between the two dynamic sealing rings is reduced by mutually pressing the elastic ring, thus, the mutual pressing force between the dynamic sealing ring and the static sealing ring can be adjusted and increased (it can also be adjusted smaller when the pressure between the two is too large). At this time, the friction force between the dynamic sealing ring and the static sealing ring is also adjusted synchronously; in this way, the high-pressure gas in the positive pressure gas cavity is sufficient to prevent the material in the material cavity from entering the positive pressure gas cavity, and it will not cause excessive pressure between the dynamic sealing ring and the static sealing ring, so as not to cause the problem of frictional overheating; that is to say, the pressure between the dynamic sealing ring and the static sealing ring is made appropriate, so that it is not only applicable to the food industry, but also there are no a series of disadvantages such as excessive friction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of the mechanical seal with a pressure-adjustable function of the present invention;

[0023] Figure 2 is Figure 1 a partial enlarged view of part A of;

[0024] Figure 3 is Figure 1 a schematic structural diagram of the axial force-adjusting pre-tightening nut of;

[0025] Figure 4 is Figure 3 a cross-sectional view of.

[0026] In the figure: 10, shaft sleeve; 101, limit ring; 20, rotating shaft; 30, elastic ring; 40, dynamic sealing ring; 50, static sealing ring; 501, radial threaded hole; 502, conical surface structure; 60, sealing sleeve; 601, external thread; 602, first air hole; 603, radial installation groove; 604, second air hole; 605, circumferential stop screw; 70, positive pressure gas cavity; 80, axial force-adjusting pre-tightening nut; 801, internal thread; 802, pressing part; 803, radial gap; 804, reaction supporting part; 8041, threaded through hole; 805, deformation part; 90, self-locking screw; 100, axial screw; 110, end plate; 120, sealing shaft ring; 130, radial fixing screw. DETAILED DESCRIPTION OF THE INVENTION

[0027] Next, in combination with the accompanying drawings and specific embodiments, the present invention will be further described. It should be noted that, on the premise of no conflict, any combination of the following-described embodiments or technical features can form a new embodiment.

[0028] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element. The "vertical", "horizontal", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only embodiment.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0030] Figure 1 - Figure 2 Shown is a mechanical seal with a pressure adjustable function according to a preferred embodiment of the present invention, including: a shaft sleeve 10, two sealing dynamic rings 40, two sealing static rings 50, a sealing sleeve 60, and an axial force adjusting pre-tightening nut 80.

[0031] The shaft sleeve 10 is used for sleeving the rotating shaft 20 and rotating synchronously with the rotating shaft 20; an elastic ring 30 is sleeved outside the shaft sleeve 10.

[0032] The sealing dynamic ring 40 is sleeved outside the shaft sleeve 10 and is circumferentially fixed to the shaft sleeve 10; the two sealing dynamic rings 40 are respectively elastically abutted against opposite sides of the elastic ring 30 so that the distance between the two sealing dynamic rings 40 is adjustable.

[0033] The sealing static ring 50 is sleeved outside the shaft sleeve 10; the two sealing dynamic rings 40 are located between the two sealing static rings 50 and respectively axially press one of the sealing static rings 50. That is to say, the sealing dynamic ring 40 is frictionally connected to the sealing static ring 50 to seal the gap therebetween, that is, when the sealing dynamic ring 40, the sealing sleeve 60, and the rotating shaft 20 rotate synchronously, the sealing dynamic ring 40 rotates relative to the sealing static ring 50.

[0034] The sealing sleeve 60 is sleeved outside the sealing dynamic ring 40, and both ends of the sealing sleeve 60 are respectively abutted (preferably fixed) against one of the sealing static rings 50 so that the two sealing dynamic rings 40, the two sealing static rings 50, and the sealing sleeve 60 jointly enclose a positive pressure air cavity 70. One end of the sealing sleeve 60 is provided with an external thread 601, and the sealing sleeve 60 is provided with a first air hole 602 communicating with the positive pressure air cavity 70.

[0035] The axially force-adjusting pre-tightening nut 80 is provided with an internal thread 801, and the internal thread 801 is in threaded fit with the external thread 601. The axially force-adjusting pre-tightening nut 80 has a pressing portion 802, and the pressing portion 802 is press-connected to one end of one of the stationary sealing rings 50 and is used to drive the stationary sealing ring 50 to press the rotating sealing ring 40.

[0036] During operation, high-pressure gas is introduced into the first air hole 602 through a positive-pressure gas source (such as an air pump) to make the positive-pressure air chamber 70 in a high-pressure state. When the air pressure in the positive-pressure air chamber 70 reaches a relatively high value, it will force the two rotating sealing rings 40 to press the elastic ring 30 against each other, so that the pressing force between the rotating sealing ring 40 and the stationary sealing ring 50 decreases, and then an air film is formed between the rotating sealing ring 40 and the stationary sealing ring 50. That is, the high-pressure gas (air or dust that may be carried in the gas storage tank) in the positive-pressure air chamber 70 will enter the material chamber or escape to the external environment. Thus, this mechanical seal with adjustable pressure function is not suitable for the food industry. Therefore, the axially force-adjusting pre-tightening nut 80 can be adjusted (i.e., rotated) in advance or in real time, so that the axially force-adjusting pre-tightening nut 80 crawls along the external thread 601, so that the pressing portion 802 presses the end of the stationary sealing ring 50 connected to it by pressing, thereby reducing the distance between the two stationary sealing rings 50, that is, making the two rotating sealing rings 40 press the elastic ring 30 against each other to reduce the distance between the two rotating sealing rings 40. In this way, the mutual pressing force between the rotating sealing ring 40 and the stationary sealing ring 50 can be adjusted and increased (it can also be adjusted smaller when the pressure between them is too large). At this time, the friction force between the rotating sealing ring 40 and the stationary sealing ring 50 is also adjusted synchronously; in this way, the high-pressure gas in the positive-pressure air chamber 70 is sufficient to prevent the material in the material chamber from entering the positive-pressure air chamber 70, and it will not cause the pressure between the rotating sealing ring 40 and the stationary sealing ring 50 to be too large, so that the problem of overheating due to friction will not occur; that is to say, the pressure between the rotating sealing ring 40 and the stationary sealing ring 50 is made appropriate, so that it is not only suitable for the food industry, but also there are no a series of drawbacks such as excessive friction.

[0037] Preferably, referring to Figure 1 - Figure 4, the axially adjustable pre-tightening nut 80 is provided with a radial gap 803. The radial gap 803 is recessed from the outer curved surface wall of the axially adjustable pre-tightening nut 80 towards the radial direction from the outside to the inside, so that reaction force supporting portions 804 and deformation portions 805 are respectively formed on opposite sides of the axially adjustable pre-tightening nut 80 where the radial gap 803 is located. The reaction force supporting portion 804 is provided with a threaded through hole 8041, and a self-locking screw 90 is threadedly connected to the threaded through hole 8041. The self-locking screw 90 extends into the radial gap 803 and can squeeze the deformation portion 805 to expand the outer edge width of the radial gap 803. With this setting, after the internal thread 801 is adjusted relative to the external thread 601, the deformation portion 805 is squeezed by the self-locking screw 90 to expand the outer edge width of the radial gap 803, so that the internal thread 801 at the position of the deformation portion 805 presses against the external thread 601 to prevent the internal thread 801 from rotating relative to the external thread 601, thereby enabling the axially adjustable pre-tightening nut 80 to have a self-locking function after adjustment to prevent the axially adjustable pre-tightening nut 80 from loosening. Obviously, this self-locking method will not increase the external dimensions of the axially adjustable pre-tightening nut 80, so that the usage scenario conditions of the axially adjustable pre-tightening nut 80 are not easily restricted by the size of the external space.

[0038] Preferably, referring to Figure 1 , both of the two static sealing rings 50 are fixedly connected to the sealing sleeve 60. With this setting, an integral structure is formed between the two static sealing rings 50 and the sealing sleeve 60, so that a gap can exist between the sealing sleeve 60 and the dynamic sealing ring 40, that is, the sealing sleeve 60 is supported by the static sealing rings 50 and does not contact the dynamic sealing ring 40.

[0039] Preferably, referring to Figure 2 , the static sealing ring 50 far from the axially adjustable pre-tightening nut 80 is circumferentially fixedly connected to the sealing sleeve 60 through an axial screw 100. In this way, the sealing sleeve 60 can be supported by this static sealing ring 50. This connection method is conducive to disassembly and maintenance. It can be understood that as an alternative setting method, the static sealing rings 50 far from the axially adjustable pre-tightening nut 80 can be fixed by a mortise and tenon structure or magnetic attraction, etc.

[0040] Preferably, referring to Figure 2, a radial threaded hole 501 is provided on the static seal ring 50 close to the axial force-adjusting pre-tightening nut 80. A radial mounting groove 603 is provided on the seal sleeve 60. A circumferential stop screw 605 is connected to the radial threaded hole 501. The head of the circumferential stop screw 605 is accommodated in the radial mounting groove 603, so that the seal sleeve 60 and the static seal ring 50 close to the axial force-adjusting pre-tightening nut 80 are circumferentially fixed together. With this setting, it can prevent the static seal ring 50 close to the axial force-adjusting pre-tightening nut 80 from rotating along with the dynamic seal ring 40. It can be understood that with this setting, the radial mounting groove 603 is provided at one end of the seal sleeve 60 and is a notch structure, and the circumferential stop screw 605 installed therein locks the seal sleeve 60 and the static seal ring 50 circumferentially together; obviously, this installation method is relatively simple, so it is also conducive to disassembly and maintenance.

[0041] Preferably, referring to Figure 1 , a limiting ring 101 is formed by radially protruding from the outer curved surface wall of the shaft sleeve 10 from the inside to the outside. The two dynamic seal rings 40 are respectively located on opposite sides of the limiting ring 101. The elastic ring 30 is sleeved outside the limiting ring 101. With this setting, the minimum distance between the two dynamic seal rings 40 is absolutely limited to prevent the extrusion force between the dynamic seal ring 40 and the static seal ring 50 from being too large, thereby avoiding the elastic ring 30 from being flattened.

[0042] Preferably, referring to Figure 1 , the seal sleeve 60 is also provided with a second air hole 604 communicating with the positive pressure air chamber 70. The first air hole 602 is used for air intake, and the second air hole 604 is used for air exhaust. With this setting, the first air hole 602 is connected to the positive pressure air source for a long time without disassembly, while the second air hole 604 only needs to pump and discharge the gas in the positive pressure air chamber 70. It can be understood that when impurities are mixed in the positive pressure air chamber 70, the impurities can be pumped out through the negative pressure pumping of the second air hole 604.

[0043] Preferably, referring to Figure 1 and Figure 2 , the static seal ring 50 far from the axial force-adjusting pre-tightening nut 80 is fixedly connected with an end plate 110, and the end plate 110 is used to be fixed to the material box and support the static seal ring 50. With this setting, that is, the two static seal rings 50 and the seal sleeve 60 are supported by the end plate 110, while the shaft sleeve 10 and the dynamic seal ring 40 are supported by the rotating shaft 20. In this way, there is no need to co-axially arrange between the static seal ring 50 and the dynamic seal ring 40, thereby reducing the manufacturing process requirements and processing difficulties.

[0044] Preferably, referring to Figure 1 and Figure 2, the inner curved surface wall of the sealing static ring 50 away from the axial force adjustment pre-tightening nut 80 is in a conical structure 502, and the small end of the conical structure 502 is closer to the sealing dynamic ring 40 than the large end of the conical structure 502. With such a setting, when flushing (cleaning) the material cavity, the spacious conical structure 502 is conducive to the flushing liquid to flush the conical structure 502 without dead angles and thoroughly to prevent material residues.

[0045] Preferably, referring to Figure 2 , one end of the shaft sleeve 10 is fitted with a sealing shaft ring 120, and the sealing shaft ring 120 is used to press-fit and hold the rotating shaft 20 tightly and axially limit the shaft sleeve 10; one end of the shaft sleeve 10 away from the sealing shaft ring 120 is connected with a radial fixing screw 130. With such a setting, the axial fixation of the shaft sleeve 10 and the rotating shaft 20 can be ensured to be more reliable to avoid the phenomenon that the shaft sleeve 10 slides relative to the rotating shaft 20.

[0046] The above embodiments are only the preferred embodiments of the present invention, and the protection scope of the present invention cannot be limited thereby. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention belong to the protection scope required by the present invention.

Claims

1. A mechanical seal with a pressure adjustable function, characterized in that Comprising: A bushing (10) for sleeving a rotating shaft (20); an elastic ring (30) is sleeved outside the bushing (10); Two sealing dynamic rings (40) are sleeved outside the bushing (10) and are circumferentially fixed to the bushing (10); the two sealing dynamic rings (40) are respectively elastically abutted against opposite sides of the elastic ring (30); Two sealing static rings (50) are sleeved outside the bushing (10); the two sealing dynamic rings (40) are located between the two sealing static rings (50) and respectively axially press one of the sealing static rings (50); A sealing sleeve (60) is sleeved outside the sealing dynamic ring (40), and both ends of the sealing sleeve (60) are abutted against one of the sealing static rings (50) respectively, so that the two sealing dynamic rings (40), the two sealing static rings (50), and the sealing sleeve (60) jointly enclose a positive pressure air cavity (70); an external thread (601) is provided at one end of the sealing sleeve (60), and the sealing sleeve (60) is provided with a first air hole (602) communicating with the positive pressure air cavity (70); An axially force-adjusting pre-tightening nut (80) is provided with an internal thread (801), and the internal thread (801) is in threaded cooperation with the external thread (601); the axially force-adjusting pre-tightening nut (80) has a pressing portion (802), and the pressing portion (802) is press-connected to one end of one of the sealing static rings (50) and is used to drive the sealing static ring (50) to press the sealing dynamic ring (40); The axially force-adjusting pre-tightening nut (80) is provided with a radial gap (803), and the radial gap (803) is recessed radially from the outer curved surface wall of the axially force-adjusting pre-tightening nut (80) from outside to inside, so that reaction force supporting portions (804) and deformation portions (805) are respectively formed on opposite sides of the axially force-adjusting pre-tightening nut (80) where the radial gap (803) is located. A threaded through hole (8041) is provided in the reaction force supporting portion (804), and a self-locking screw (90) is threadedly connected to the threaded through hole (8041). The self-locking screw (90) extends into the radial gap (803) and can press the deformation portion (805) to expand the outer edge width of the radial gap (803); a end plate (110) is fixedly connected to the sealing static ring (50) away from the axially force-adjusting pre-tightening nut (80).

2. The mechanical seal with a pressure adjustable function according to claim 1, characterized in that: Both of the two sealing static rings (50) are fixedly connected to the sealing sleeve (60).

3. The mechanical seal with a pressure adjustable function as claimed in claim 2, wherein: The sealing static ring (50) away from the axially force-adjusting pre-tightening nut (80) is circumferentially fixedly connected to the sealing sleeve (60) through an axial screw (100).

4. The mechanical seal with a pressure adjustable function according to claim 3, characterized in that: The sealing static ring (50) close to the axial force-adjusting pre-tightening nut (80) is provided with a radial threaded hole (501). The sealing sleeve (60) is provided with a radial mounting groove (603). The radial threaded hole (501) is connected with a circumferential stop screw (605). The head of the circumferential stop screw (605) is accommodated in the radial mounting groove (603) so that the sealing sleeve (60) is circumferentially fixed together with the sealing static ring (50) close to the axial force-adjusting pre-tightening nut (80).

5. The mechanical seal with a pressure adjustable function according to claim 1, characterized in that: The shaft sleeve (10) is provided with a limiting ring (101) protruding radially from the inside to the outside on the outer curved surface wall of itself. The two sealing dynamic rings (40) are respectively located on opposite sides of the limiting ring (101). The elastic ring (30) is sleeved outside the limiting ring (101).

6. The mechanical seal with a pressure adjustable function according to claim 1, characterized in that: The sealing sleeve (60) is further provided with a second air hole (604) communicating with the positive pressure air cavity (70). The first air hole (602) is used for air intake, and the second air hole (604) is used for air exhaust.

7. The mechanical seal with a pressure adjustable function according to claim 1, characterized in that: The end plate (110) is used for being fixed to the material box and supporting the sealing static ring (50).

8. The mechanical seal with a pressure adjustable function according to claim 1, characterized in that: The inner curved surface wall of the sealing static ring (50) far from the axial force-adjusting pre-tightening nut (80) is in a conical structure (502), and the small end of the conical structure (502) is closer to the sealing dynamic ring (40) than the large end of the conical structure (502).

9. The mechanical seal with a pressure adjustable function as claimed in claim 1, characterized in that: One end of the shaft sleeve (10) is fitted with a sealing shaft ring (120). The sealing shaft ring (120) is used for tightly pressing the rotating shaft (20) by interference fit and axially limiting the shaft sleeve (10). One end of the shaft sleeve (10) far from the sealing shaft ring (120) is connected with a radial fixing screw (130).

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