Shaft seal structure of a screw pump

Abstract

The utility model provides a kind of shaft seal structure of screw pump, belong to screw pump technical field.It solves the problem of higher difficulty of maintenance of existing screw pump.The shaft seal structure of this screw pump, screw pump includes pump body and the pump shaft rotationally connected in pump body, pump body includes working chamber and lubricating chamber, this shaft seal structure includes the labyrinth centrifugal disc and oil throwing disc of being located between working chamber and lubricating chamber and being all sleeved on pump shaft, this shaft seal structure further includes the floating isolation ring of being sleeved on pump shaft, floating isolation ring is located between labyrinth centrifugal disc and oil throwing disc and with labyrinth centrifugal disc and oil throwing disc along axial abut, multiple installation grooves are set on floating isolation ring outer side wall, floating isolation ring outer sleeve is provided with pressure sleeve, and there is gas gap between pressure sleeve and floating isolation ring.The shaft seal structure of this screw pump can both guarantee the sealing effect of shaft seal structure and extend the service life of floating seal ring.

Description

Technical Field

[0001] This utility model belongs to the field of screw pump technology and relates to a shaft seal structure for a screw pump. Background Technology

[0002] When a screw pump is running, lubricating oil is needed to lubricate the internal bearings and other components. Since screw pumps need to compress gaseous or liquid media, a shaft seal structure is added to the pump shaft to separate the media from the lubricating oil and prevent the lubricating oil from contaminating the media.

[0003] Existing shaft seal structures, such as the Chinese patent application [Authorization Announcement No.: CN202203111U] which discloses an anti-scaling mechanical seal structure for a twin-screw pump used for oil and gas mixed transport, include a mechanical seal chamber seat, which is mounted on the pump body side plate. A mechanical seal chamber cover is installed on the mechanical seal chamber seat. A stationary mechanical seal ring is mounted on the mechanical seal chamber seat, and a rotating mechanical seal ring is mounted on the pump shaft. The stationary and rotating mechanical seal rings form a friction pair that fits against each other. The sealing ring is floatingly mounted inside the mechanical seal chamber cover. The inner hole of the sealing ring is clearance-fitted with the outer circle of the rotating mechanical seal ring. A sealing ring pressure plate is installed on the outside of the mechanical seal chamber cover. An oil seal is also provided on the side of the mechanical seal chamber seat away from the mechanical seal chamber cover. The space between the oil seal, the mechanical seal chamber seat, the stationary mechanical seal ring, and the rotating mechanical seal ring forms a lubricating oil cavity. The space between the pump body side plate, the mechanical seal chamber seat, the stationary mechanical seal ring, the rotating mechanical seal ring, the mechanical seal ring, and the mechanical seal chamber cover forms a grease cavity.

[0004] The above structure uses a friction pair formed by the stationary and rotating mechanical seal rings to isolate the pump. However, the rotating mechanical seal ring needs to be fitted onto the pump shaft, and it rotates with the pump shaft. The rotating mechanical seal ring and the pump shaft are connected by a tight fit or interference fit. When the temperature of the entire pump chamber rises, the pump shaft expands radially and squeezes the rotating mechanical seal ring, causing deformation of the rotating mechanical seal ring. This affects the sealing effect of the rotating mechanical seal ring, resulting in frequent replacement of the rotating mechanical seal ring and increasing the maintenance difficulty of the screw pump. Utility Model Content

[0005] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a shaft seal structure for a screw pump. The technical problem this invention aims to solve is: how to address the high maintenance difficulty of existing screw pumps.

[0006] The objective of this utility model can be achieved through the following technical solutions:

[0007] A shaft seal structure for a screw pump, the screw pump including a pump body and a pump shaft rotatably connected to the pump body, the pump body including a working chamber and a lubrication chamber, the shaft seal structure including a labyrinth centrifugal disc and an oil slinger disc both sleeved on the pump shaft and located between the working chamber and the lubrication chamber, characterized in that the shaft seal structure further includes a floating isolation ring sleeved on the pump shaft, the floating isolation ring being located between the labyrinth centrifugal disc and the oil slinger disc and abutting against the labyrinth centrifugal disc and the oil slinger disc axially, the outer side wall of the floating isolation ring having multiple mounting grooves, the floating isolation ring being fitted with a pressure sleeve, and the pressure sleeve having an air passage gap between the floating isolation ring, the inner side wall of the pressure sleeve having piston rings corresponding to the mounting grooves and embedded in the corresponding mounting grooves, the pump body also having an air inlet channel, the air inlet channel communicating with the air passage gap.

[0008] When a screw pump compresses a medium, it has a working chamber and a lubrication chamber. The working chamber contains media such as dust and liquid, while the lubrication chamber is filled with lubricant to lubricate the existing bearings in the screw pump, ensuring that the pump shaft can rotate stably relative to the pump body. To prevent the medium and lubricating oil in the working chamber from interfering with each other, a labyrinth centrifugal disc, a floating isolation ring, and an oil slinger are installed between the working chamber and the lubrication chamber. The labyrinth centrifugal disc throws out the large-mass medium molecules in the working chamber, and the oil slinger throws a large amount of lubricating oil back into the lubricating oil through the centrifugal force of the pump shaft. However, a small amount of small-mass medium molecules and lubricating oil still enter the floating isolation ring. An air inlet channel is provided on the pump body, allowing high-pressure nitrogen gas from the outside to be introduced into the air inlet channel. The gas flows out through the air gap, while the high-pressure nitrogen gas in the air inlet channel... The floating isolation ring is pressed onto the pump shaft, and the piston ring also serves to press the floating isolation ring onto the pump shaft, improving the seal between the floating isolation ring and the pump shaft. On the other hand, by allowing high-pressure gas to flow out from the gas gap, the medium and lubricating oil on both sides are blown out and returned to the labyrinth centrifugal disc and oil slinger disc to be thrown out. Thus, through the effect of quadruple sealing, the medium in the working chamber is isolated from the lubricating oil in the lubrication chamber. In order to extend the service life of the floating sealing ring, the floating sealing ring is directly fitted onto the pump shaft. There is a small gap between the floating sealing ring and the pump shaft. When the screw pump expands under normal operation, the piston ring and high-pressure gas can achieve the cooperation between the floating sealing ring and the pump shaft, which can prevent the medium and lubricating oil from flowing into the small gap between the floating sealing ring and the pump shaft. This can ensure the sealing effect of the shaft seal structure and extend the service life of the floating sealing ring.

[0009] In the aforementioned screw pump shaft seal structure, an annular relief groove is provided on the middle of the outer side wall of the floating isolation ring, and the mounting grooves are located on both sides of the relief groove. The air intake channel is connected to the relief groove.

[0010] By connecting the air intake channel with the relief groove, the high-pressure gas can be buffered at the relief groove before slowly flowing into both sides of the relief groove and flowing out from the air gap. On the one hand, it can press the middle of the floating isolation ring, and on the other hand, it can stably discharge the medium and lubricating oil in the air gap with high-pressure gas, thereby extending the service life of the floating isolation ring and improving the shaft sealing effect.

[0011] In the aforementioned screw pump shaft seal structure, there are four mounting slots, and the mounting slots are arranged in pairs on both sides of the clearance slot.

[0012] The mounting groove design allows for a more even distribution of piston rings on both sides of the groove, which in turn enables the floating seal ring to be stably pressed onto the pump shaft by the high-pressure gas and the elasticity of the piston rings, thus improving the fit between the floating seal ring and the pump shaft during operation of the screw pump.

[0013] In the aforementioned screw pump shaft seal structure, a positioning bushing is fixedly connected to the pump body, and a spiral sleeve is sleeved on the pump shaft. The spiral sleeve has helical teeth that rotate in the opposite direction to the screw on the pump shaft. The spiral sleeve is located inside the positioning bushing, and the helical teeth are located between the working chamber and the labyrinth centrifugal disc.

[0014] By setting helical teeth on the helical sleeve in the opposite direction to the screw rotation, a layer of seal can be formed on the medium in the working chamber, which can block some dust or liquid medium, thereby improving the shaft sealing effect of the shaft seal structure.

[0015] In the shaft seal structure of the screw pump described above, a material guide groove is provided radially on the labyrinth centrifugal disc, and the material guide groove is radially opposite to the outlet of the labyrinth centrifugal disc.

[0016] The material guide groove on the labyrinth centrifugal disc allows large-mass media to be ejected from the outlet through the material guide groove by the high-speed rotation of the labyrinth centrifugal disc, so that only small-mass media enter the gas passage gap. This facilitates the pushing of small-mass media by high-pressure gas, thereby further improving the overall shaft sealing effect.

[0017] In the aforementioned screw pump shaft seal structure, one end of the oil slinger is bent to form an annular oil baffle, which is located outside the pressure sleeve.

[0018] The oil baffle further reduces the amount of oil thrown out by the oil slinger from the oil slinger plate from entering the pressure sleeve and floating isolation ring, so that only a small amount of lubricating oil enters the air gap, which is then easily blown out by high-pressure gas, achieving a better shaft sealing effect.

[0019] In the shaft seal structure of the screw pump described above, there is a waste discharge gap between the spiral sleeve and the labyrinth centrifugal disc, and the pump body is provided with an exhaust port and a flow guide channel on the side near the working chamber. The waste discharge gap is connected to the exhaust port through the flow guide channel.

[0020] Because the labyrinth centrifugal disc throws out a large mass of medium at high speed, impurities are directly discharged from the exhaust port through the outflow of high-pressure gas. This facilitates the discharge of gas and also helps to discharge some of the medium that has flowed out of the working chamber, thus improving the stability of the shaft seal structure.

[0021] Compared with existing technologies, the shaft seal structure of this screw pump has the following advantages: Through the effect of quadruple sealing, the medium in the working chamber is isolated from the lubricating oil in the lubrication chamber. In order to improve the service life of the floating seal ring, the floating seal ring is directly fitted onto the pump shaft. There is a tiny gap between the floating seal ring and the pump shaft. When the screw pump expands under normal operation, the piston ring and high-pressure gas can achieve the cooperation between the floating seal ring and the pump shaft, which can prevent the medium and lubricating oil from flowing into the tiny gap between the floating seal ring and the pump shaft. Thus, it can both ensure the sealing effect of the shaft seal structure and extend the service life of the floating seal ring. Attached Figure Description

[0022] Figure 1 This is a half-sectional view of the assembled version of this utility model.

[0023] Figure 2 This is a partial sectional view of the assembled version of this utility model.

[0024] Figure 3 yes Figure 2 A magnified view of a portion of point A in the middle.

[0025] Figure 4 This is a front view of the labyrinth centrifugal disc in this utility model.

[0026] In the diagram, 1. Pump body; 11. Working chamber; 12. Lubrication chamber; 13. Air inlet channel; 14. Exhaust port; 15. Flow guide channel; 2. Pump shaft; 21. Screw; 3. Labyrinth centrifugal disc; 31. Material guide groove; 32. Outlet; 4. Oil slinger; 41. Oil baffle; 5. Floating isolation ring; 51. Mounting groove; 52. Clearance groove; 6. Pressure sleeve; 7. Air passage gap; 8. Piston ring; 9. Positioning bushing; 10. Spiral sleeve; 101. Spiral teeth; 102. Impurity discharge gap. Detailed Implementation

[0027] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0028] like Figure 1 and Figure 2As shown, the shaft seal structure of this screw pump includes a pump body 1 and a pump shaft 2 rotatably connected within the pump body 1. The pump body 1 includes a working chamber 11 and a lubrication chamber 12. The shaft seal structure includes a labyrinth centrifugal disc 3 and an oil slinger disc 4, both sleeved on the pump shaft 2 and located between the working chamber 11 and the lubrication chamber 12.

[0029] Specifically, such as Figure 2 As shown in Figure 3, this shaft seal structure also includes a floating isolation ring 5 sleeved on the pump shaft 2. The floating isolation ring 5 is located between the labyrinth centrifugal disc 3 and the oil slinger disc 4 and abuts against the labyrinth centrifugal disc 3 and the oil slinger disc 4 along the axial direction. Multiple mounting grooves 51 are provided on the outer wall of the floating isolation ring 5. A pressure sleeve 6 is provided on the outer sleeve of the floating isolation ring 5, and there is an air passage gap 7 between the pressure sleeve 6 and the floating isolation ring 5. The inner wall of the pressure sleeve 6 has piston rings 8 that are set one-to-one with the mounting grooves 51 and embedded in the corresponding mounting grooves 51. An air inlet channel 13 is also provided on the pump body 1, and the air inlet channel 13 is connected to the air passage gap 7.

[0030] When a screw pump compresses a medium, it is equipped with a working chamber 11 and a lubrication chamber 12. The working chamber 11 contains media such as dust and liquid, while the lubrication chamber 12 is filled with lubricant to lubricate the existing bearings in the screw pump, ensuring that the pump shaft 2 can rotate stably relative to the pump body 1. To prevent the medium and lubricating oil in the working chamber 11 from interfering with each other, a labyrinth centrifugal disc 3, a floating isolation ring 5, and an oil slinger 4 are installed between the working chamber 11 and the lubrication chamber 12 for isolation. The labyrinth centrifugal disc 3 can throw out the large-mass medium molecules in the working chamber 11, and the oil slinger 4 can throw a large amount of lubricating oil back into the lubricating oil through the centrifugal force of the pump shaft 2. However, a small amount of small-mass medium molecules and lubricating oil still enter the floating isolation ring 5. An air inlet channel 13 is provided on the pump body 1, and high-pressure nitrogen gas is introduced into the air inlet channel 13. The air inlet channel 13 flows out through the air gap 7. The high-pressure nitrogen gas inside the pump shaft 2 presses the floating isolation ring 5 against the pump shaft 2, and the piston ring 8 also presses the floating isolation ring 5 against the pump shaft 2, improving the seal between the floating isolation ring 5 and the pump shaft 2. On the other hand, the high-pressure gas flows out from the gas gap 7, blowing out the medium and lubricating oil on both sides, and returning to the labyrinth centrifugal disc 3 and the oil slinger disc 4 to be thrown out. Thus, through the effect of quadruple sealing, the medium in the working chamber 11 is isolated from the lubricating oil in the lubrication chamber 12. In order to improve the service life of the floating sealing ring, the floating sealing ring is directly fitted onto the pump shaft 2. There is a small gap between the floating sealing ring and the pump shaft 2. When the screw pump expands under normal operation, the piston ring 8 and the high-pressure gas can achieve the cooperation between the floating sealing ring and the pump shaft 2, which can prevent the medium and lubricating oil from flowing into the small gap between the floating sealing ring and the pump shaft 2. Thus, it can both ensure the sealing effect of the shaft seal structure and extend the service life of the floating sealing ring.

[0031] like Figure 2 As shown in Figure 3, a ring-shaped clearance groove 52 is provided on the middle of the outer side wall of the floating isolation ring 5. The mounting grooves 51 are all located on both sides of the clearance groove 52. The air intake channel 13 is connected to the clearance groove 52. There are four mounting grooves 51, and the mounting grooves 51 are arranged in pairs on both sides of the clearance groove 52.

[0032] like Figure 2-4 As shown, a positioning bushing 9 is fixedly connected inside the pump body 1, and a spiral sleeve 10 is sleeved on the pump shaft 2. The spiral sleeve 10 has spiral teeth 101 that rotate in the opposite direction to the screw 21 on the pump shaft 2. The spiral sleeve 10 is located inside the positioning bushing 9, and the spiral teeth 101 are located between the working chamber 11 and the labyrinth centrifugal disc 3. A material guide groove 31 is radially opened on the labyrinth centrifugal disc 3. The material guide groove 31 and the outlet 32 ​​of the labyrinth centrifugal disc 3 are radially opposite each other. There is a waste discharge gap 102 between the spiral sleeve 10 and the labyrinth centrifugal disc 3. An exhaust port 14 and a flow guide channel 15 are provided on the side of the pump body 1 near the working chamber 11. The waste discharge gap 102 is connected to the exhaust port 14 through the flow guide channel 15.

[0033] like Figure 3 As shown, one end of the oil slinger 4 is bent to form an annular oil baffle 41, which is located outside the pressure sleeve 6.

[0034] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A shaft seal structure for a screw pump, the screw pump comprising a pump body (1) and a pump shaft (2) rotatably connected within the pump body (1), the pump body (1) comprising a working chamber (11) and a lubrication chamber (12), the shaft seal structure comprising a labyrinth centrifugal disc (3) and an oil slinger disc (4) both sleeved on the pump shaft (2) and located between the working chamber (11) and the lubrication chamber (12), characterized in that, The shaft seal structure also includes a floating isolation ring (5) sleeved on the pump shaft (2). The floating isolation ring (5) is located between the labyrinth centrifugal disc (3) and the oil slinger disc (4) and abuts against the labyrinth centrifugal disc (3) and the oil slinger disc (4) along the axial direction. Multiple mounting grooves (51) are provided on the outer side wall of the floating isolation ring (5). A pressure sleeve (6) is provided on the outer side of the floating isolation ring (5), and there is an air passage gap (7) between the pressure sleeve (6) and the floating isolation ring (5). The inner side wall of the pressure sleeve (6) has piston rings (8) that are correspondingly set and embedded in the corresponding mounting grooves (51). An air inlet channel (13) is also provided on the pump body (1), and the air inlet channel (13) is connected to the air passage gap (7).

2. The shaft seal structure of the screw pump according to claim 1, characterized in that, The floating isolation ring (5) has an annular relief groove (52) on the middle of its outer side wall. The mounting grooves (51) are located on both sides of the relief groove (52). The air intake channel (13) is connected to the relief groove (52).

3. The shaft seal structure of the screw pump according to claim 2, characterized in that, The mounting slots (51) are provided in four pairs, and the mounting slots (51) are located on both sides of the clearance slots (52).

4. The shaft seal structure of the screw pump according to claim 1, 2, or 3, characterized in that, A positioning bushing (9) is fixedly connected inside the pump body (1), and a spiral sleeve (10) is sleeved on the pump shaft (2). The spiral sleeve (10) has spiral teeth (101) that rotate in the opposite direction to the screw (21) on the pump shaft (2). The spiral sleeve (10) is located inside the positioning bushing (9), and the spiral teeth (101) are located between the working chamber (11) and the labyrinth centrifugal disc (3).

5. The shaft seal structure of the screw pump according to claim 1, 2, or 3, characterized in that, The labyrinth centrifugal disc (3) is provided with a material guide groove (31) along the radial direction, and the material guide groove (31) and the outlet (32) of the labyrinth centrifugal disc (3) are arranged directly opposite each other in the radial direction.

6. The shaft seal structure of the screw pump according to claim 1, 2, or 3, characterized in that, One end of the oil slinger (4) is bent to form an annular oil baffle (41), which is located outside the pressure sleeve (6).

7. The shaft seal structure of the screw pump according to claim 4, characterized in that, There is a waste discharge gap (102) between the spiral sleeve (10) and the labyrinth centrifugal disc (3). The pump body (1) is provided with an exhaust port (14) and a flow guide channel (15) on the side near the working chamber (11). The waste discharge gap (102) is connected to the exhaust port (14) through the flow guide channel (15).

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