Screw pump with four-seal structure

Abstract

The application discloses a screw pump with a quadruple sealing structure, comprising an end plate and a shaft, at least one mounting hole is arranged in the end plate, the shaft is rotatably arranged in the mounting hole, a piston ring and a shaft seal are arranged on the shaft to form a sealing area, an oil retaining ring is fixedly arranged on the shaft, a plurality of annular protrusions are arranged on the outer wall of the oil retaining ring, a plurality of annular grooves are arranged on the inner wall of the end plate, the annular protrusions and the annular grooves are staggered and distributed to form a labyrinth seal inside the end plate, the end plate is further provided with a through hole aligned with the shaft seal, and the through hole is filled with buffer gas to form an air barrier seal. The screw pump has the quadruple sealing structure, can realize more reliable sealing effect through mutual cooperation, can ensure stable operation of the screw pump under harsh working conditions, and can maintain a high sealing level when one of the sealing structures is damaged. The application has the advantages of high sealing performance and good stability.

Description

Technical Field

[0001] This application relates to the fields of fluid machinery and sealing technology, and in particular to a screw pump with a quadruple sealing structure. Background Technology

[0002] Screw pumps, as a type of positive displacement rotary pump, are widely used in petrochemical, food and pharmaceutical, and energy extraction industries due to their outstanding advantages such as stable delivery and pressure stability. Shaft end sealing performance is a key indicator for evaluating the technical level and operational reliability of screw pumps. Installing a reliable sealing structure at the shaft end of the screw pump not only effectively prevents internal media leakage and ensures the safety of the external environment, but also maintains stable internal pressure within the pump chamber, thereby ensuring efficient media delivery.

[0003] However, the sealing structures of commonly used screw pumps are relatively simple, often employing a single sealing sleeve to seal the internal shaft. This results in limited sealing performance and insufficient adaptability. Especially under harsh operating conditions, if the sealing structure fails, the pump medium will leak directly to the outside, not only polluting the environment and posing safety hazards, but also severely affecting the normal operating efficiency and service life of the screw pump. Therefore, there is an urgent need for a screw pump with a multi-layered sealing structure to improve its overall sealing reliability and environmental adaptability. Summary of the Invention

[0004] One objective of this application is to provide a screw pump with a quadruple sealing structure that can solve at least one of the defects in the aforementioned background technology.

[0005] To achieve at least one of the above objectives, the technical solution adopted in this application is as follows: a screw pump with a quadruple sealing structure, comprising an end plate and a shaft, wherein the end plate has at least one mounting hole, the shaft is rotatably mounted in the mounting hole, and the shaft is provided with a first sealing mechanism and a second sealing mechanism for forming a sealing area; wherein the first sealing mechanism includes a piston ring seat, the piston ring seat is sleeved with the shaft, a piston ring is mounted on the outer side of the piston ring seat, and the piston ring is in close contact with the inner wall of the mounting hole; the second sealing mechanism includes a shaft seal. The shaft seal is located near the end of the piston ring seat and is sleeved with the shaft. The inner wall of the shaft seal has at least one sealing lip for sealing the shaft. An oil baffle ring is fixedly installed on the shaft. The outer wall of the oil baffle ring has multiple annular protrusions. The inner wall of the end plate has multiple annular grooves. The multiple annular protrusions and annular grooves are staggered to form a labyrinth seal. The end plate also has a through hole aligned with the shaft seal. The through hole is filled with buffer gas to form a gas barrier seal. The buffer gas is used to seal the medium inside the end plate.

[0006] Through the above settings, the screw pump cavity can be quadrupled sealed. The four sealing structures can work together to achieve a more reliable sealing effect, ensuring that the screw pump can operate stably under harsh conditions. When one sealing structure is damaged, the remaining sealing structures can still maintain a high sealing level, ensuring that the screw pump can continue to work. The piston ring installed on the piston ring seat is the first seal. The piston ring can rely on its own elasticity to fit tightly with the inner wall of the mounting hole, which can effectively block powder in the gas. The shaft seal is the second seal. After the sealing lip fits with the shaft, it can form a physical sealing surface to prevent media leakage. The gas barrier seal is the third seal. By continuously filling the through hole with buffer gas, it can work with the shaft seal to form a continuous gas film barrier at the sealing gap to avoid internal media leakage. The labyrinth seal is the fourth seal. The oil baffle ring is similar to a moving ring structure and rotates synchronously with the shaft. The end plate is similar to a stationary ring, and the annular grooves and annular protrusions are distributed alternately to form a labyrinth gap. When the oil baffle ring and the end plate rotate relative to each other, the throttling effect of the medium in the gap is used to achieve sealing.

[0007] Preferably, the piston ring seat has multiple recesses, and the piston ring is positioned and fixed within these recesses. This configuration increases the number of piston rings installed, further improving the sealing effect of the screw pump; the recesses also limit the piston ring's position, preventing it from shifting.

[0008] Preferably, the shaft is provided with a sealing groove, the sealing groove having an overlapping surface with the piston ring seat, and a sealing ring is installed in the sealing groove. This arrangement allows the sealing effect of the piston ring seat to be further improved through the sealing groove and the sealing ring, preventing leakage of the medium through the gap between the piston ring seat and the shaft.

[0009] Preferably, there are two sealing lips, and the two sealing lips bend in opposite directions, with each sealing lip sealing one end of the shaft seal. This configuration allows for bidirectional sealing via the two sealing lips. When pressure in the sealing area fluctuates bidirectionally, the two oppositely bent sealing lips can simultaneously seal the medium on both sides, thereby enhancing the sealing reliability of the shaft seal.

[0010] Preferably, a wear-resistant ring is fixedly sleeved on the shaft, the shaft seal is sleeved with the wear-resistant ring, and the sealing lip is tightly fitted with the outer wall of the wear-resistant ring. This configuration allows the wear-resistant ring to act as a protective device between the shaft seal and the shaft. When the shaft rotates, it drives the wear-resistant ring to rotate synchronously. At this time, the sealing lip can only rub against the outer wall of the wear-resistant ring, thus preventing scratches on the shaft surface. When the wear-resistant ring is damaged, it can be replaced with a new one in a timely manner, further reducing the maintenance and repair costs of the screw pump.

[0011] Preferably, the wear ring is provided with perforations. This configuration allows for the establishment of a pressure balance channel through the perforations. During screw pump operation, some media may seep into the area between the two sealing lips through the tiny gap between the sealing lip and the wear ring, causing excessive pressure in the area between the two sealing lips. The perforations then act as a pressure relief device, guiding some of the media to the shaft surface. In addition, some of the media flowing out of the perforations can also lubricate and cool the shaft and the wear ring.

[0012] Preferably, the end plate is provided with a vent hole, one end of which is connected to the annular groove and the other end is connected to the outside. This arrangement allows some of the high-pressure gas within the sealing area to enter the labyrinth seal, and then the high-pressure gas flows to the outside through the vent hole, thus preventing excessive pressure in the sealing area. Furthermore, when there is a trace amount of leaking medium inside the labyrinth seal, it can be discharged through the vent hole to prevent the medium from accumulating inside the labyrinth seal and affecting the sealing effect.

[0013] Preferably, a bearing is installed in the mounting hole, and a sealing ring is installed between the mounting hole and the mating surface of the bearing. The bearing is inserted into the shaft, and the end of the bearing abuts against the end of the oil retainer ring. This configuration allows the bearing to be sealed within the mounting hole by the sealing ring, and the bearing can limit the position of the shaft, preventing angular deviation. When the shaft rotation becomes stuck, lubricating oil can be added to the bearing to make the shaft rotation smoother.

[0014] Preferably, a pressure ring is mounted on the end plate, the pressure ring extending into the mounting hole and fitting against the outer ring of the bearing. This configuration allows the pressure ring to limit the position of the bearing's outer ring, preventing any displacement of the bearing's position.

[0015] Preferably, a fixing member is installed on the shaft, and the fixing member fits against the inner ring of the bearing. This arrangement allows the fixing member to limit the movement of the inner ring of the bearing. After the bearing is installed, the fixing member and the pressure ring work together to provide a more secure hold for the entire bearing.

[0016] Compared with the prior art, the beneficial effects of this application are as follows: (1) The screw pump is equipped with a quadruple sealing structure. The four sealing structures can work together to achieve a more reliable sealing effect for the screw pump, so as to ensure that the screw pump can operate stably under harsh working conditions. When one of the sealing structures is damaged, the other sealing structures can also maintain a high sealing level, ensuring that the screw pump can continue to work.

[0017] (2) After the sealing lip contacts the shaft, a physical sealing surface can be formed. The two sealing lips can simultaneously provide bidirectional sealing to the shaft, thereby enhancing the sealing reliability of the shaft seal. The buffer gas continuously injected into the through hole can work with the shaft seal to form a continuous gas film barrier at the sealing gap, preventing internal media leakage.

[0018] (3) Perforation can create a pressure balance channel on the wear ring. When the pressure between the two sealing lips is too high, the pressure can be reduced through perforation, and some of the medium can be guided to the shaft surface. In addition, some of the medium flowing out from the perforation can also lubricate and cool the shaft and wear ring.

[0019] (4) An exhaust port connected to the labyrinth seal is provided on the end plate. Some of the high-pressure gas in the sealing area will enter the labyrinth seal, and then the high-pressure gas will flow to the outside through the exhaust port to avoid excessive pressure in the sealing area. This invention has the advantages of high sealing performance and good stability. Attached Figure Description

[0020] Figure 1 This is a cross-sectional structural diagram of the screw pump in this application.

[0021] Figure 2 for Figure 1 A magnified structural diagram of part A in the middle.

[0022] Figure 3 for Figure 1 A magnified structural diagram of local area B in the middle.

[0023] Figure 4 This is a schematic diagram of the exploded structure of the screw pump in this application.

[0024] Figure 5 This is a schematic diagram of the screw pump in this application.

[0025] Figure 6 This is a schematic diagram of the installation structure of the shaft seal and the wear ring.

[0026] In the diagram: 1. End plate; 11. Mounting hole; 12. Annular groove; 13. Vent hole; 100. Shaft; 101. Sealing groove; 102. Fixing component; 2. Piston ring seat; 21. Recess; 200. Through hole; 3. Shaft seal; 31. Sealing lip; 300. Wear ring; 301. Perforation; 4. Oil retainer ring; 41. Annular protrusion; 400. Bearing; 5. Pressure ring. Detailed Implementation

[0027] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0028] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0029] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0030] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0031] One aspect of this application provides a screw pump with a quadruple seal structure, one preferred embodiment of which is, for example... Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the screw pump includes an end plate 1 and a shaft 100. The end plate 1 has at least one mounting hole 11, and the shaft 100 is rotatably mounted within the mounting hole 11. The shaft 100 is equipped with a first sealing mechanism and a second sealing mechanism to form a sealing area inside the end plate 1, thereby sealing the internal medium of the screw pump. The first sealing mechanism includes a piston ring seat 2, which is directly sleeved onto the shaft 100. A piston ring (not shown) is mounted on the piston ring seat 2 and is in close contact with the inner wall of the mounting hole 11 to block powder in the gaseous medium. The second sealing mechanism includes a shaft seal 3, located near the end of the piston ring seat 2. The inner wall of the shaft seal 3 has at least one sealing lip 31. A wear-resistant ring 300 is fixedly sleeved onto the shaft 100. The shaft seal 3 is sleeved onto the wear-resistant ring 300, and the sealing lip 31 directly contacts the outer wall of the wear-resistant ring 300 to form a physical sealing surface, preventing medium leakage. The end plate 1 is provided with a through hole 200 aligned with the shaft seal 3. The through hole 200 is filled with buffer gas to form an air barrier seal. The buffer gas is used to seal the medium inside the end plate 1. By continuously filling the through hole 200 with buffer gas, a continuous air film barrier can be formed at the sealing gap with the shaft seal 3 to prevent internal medium leakage. An oil baffle ring 4 is fixedly installed on the shaft 100. The outer wall of the oil baffle ring 4 is provided with multiple annular protrusions 41, and the inner wall of the end plate 1 is provided with multiple annular grooves 12. The multiple annular grooves 12 and multiple annular protrusions 41 are staggered and form a labyrinth seal inside the end plate 1. The oil baffle ring 4 is similar to a moving ring structure and rotates synchronously with the shaft 100. The end plate 1 is similar to a stationary ring, and the annular grooves 12 and annular protrusions 41 are staggered and form a labyrinth gap. When the oil baffle ring 4 and the end plate 1 rotate relative to each other, the throttling effect of the medium in the gap is used to achieve sealing.

[0032] It should be noted that buffer gases include, but are not limited to, nitrogen. In addition, buffer gases should have properties such as being clean, dry, and stable.

[0033] It is understood that this application uses the wear ring 300 as a protective device between the shaft seal 3 and the shaft 100. When the shaft 100 rotates, it drives the wear ring 300 to rotate synchronously. At this time, the sealing lip 31 can only rub against the outer wall of the wear ring 300, thereby avoiding scratches on the surface of the shaft 100. When the wear ring 300 is damaged, a new wear ring 300 can be replaced in time, further reducing the maintenance and repair costs of the screw pump.

[0034] In addition, in order to ensure that the sealing lip 31 can maintain a tight fit with the wear ring 300, the sealing lip 31 itself should be elastic. The material of the sealing lip 31 includes, but is not limited to, rubber, so that the sealing lip 31 can apply a continuous pre-tightening force to the wear ring 300 through its own elasticity after assembly, thus ensuring the fit and sealing performance of the sealing lip 31.

[0035] It should be noted that the sealing structure inside a traditional screw pump is relatively simple. Under harsh working conditions, the simple sealing structure is more prone to failure. If the sealing structure is damaged when the screw pump is working, it will not only harm the external environment, but also seriously affect the work efficiency.

[0036] In this application, the piston ring installed on the piston ring seat 2 is the first seal, the shaft seal 3 is the second seal, the air barrier seal is the third seal, and the labyrinth seal is the fourth seal. The four sealing structures work together to achieve a more reliable sealing effect on the cavity of the screw pump, so as to ensure that the screw pump can operate stably under harsh working conditions. When one of the sealing structures is damaged, the remaining sealing structures can also maintain a high sealing level, ensuring that the screw pump can continue to work.

[0037] Furthermore, such as Figure 2 As shown, the piston ring seat 2 is provided with multiple recesses 21, and a piston ring is installed in each recess 21. The piston ring itself is elastic. When the piston ring seat 2 enters the mounting hole 11, the piston ring can rely on its own elasticity to tightly fit with the inner wall of the mounting hole 11. The recesses 21 can also limit the piston ring to prevent the piston ring from shifting under pressure impact, thereby improving the sealing effect of the screw pump.

[0038] It should be noted that the piston ring material includes, but is not limited to, materials with anti-slip and wear-resistant properties such as rubber and soft plastic. The specific number and size of the recesses 21 are not limited, and those skilled in the art can adjust them according to the actual situation.

[0039] Specifically, such as Figure 1 and Figure 2 As shown, a sealing groove 101 is provided on the shaft 100. The sealing groove 101 overlaps with the piston ring seat 2. A sealing ring is installed in the sealing groove 101. When installing the piston ring seat 2, the sealing ring is first placed in the sealing groove 101, and then the piston ring seat 2 is partially inserted over the sealing ring and sleeved onto the shaft 100. The sealing effect of the piston ring seat 2 can be further improved by the sealing groove 101 in conjunction with the sealing ring, preventing the medium from leaking through the sleeve gap between the piston ring seat 2 and the shaft 100.

[0040] In this embodiment, as Figure 2 As shown, there are two sealing lips 31, and the two sealing lips 31 bend in opposite directions. The two sealing lips 31 seal both ends of the shaft seal 3 respectively, thereby achieving bidirectional sealing of the shaft 100. When the pressure in the sealing area fluctuates bidirectionally, the two sealing lips 31 that bend in opposite directions can simultaneously seal the medium on both sides, thereby enhancing the sealing reliability of the shaft seal 3.

[0041] It should be understood that during the operation of the screw pump, some of the medium will seep into the space between the two sealing lips 31 through the tiny gap between the sealing lip 31 and the wear ring 300, resulting in excessive pressure in the area between the two sealing lips 31, which in turn affects the sealing effect of the sealing lip 31.

[0042] In this embodiment, such as Figure 2 and Figure 5 As shown, the wear ring 300 is provided with a perforation 301. The sealing lip 31 and the shaft 100 are connected through the perforation 301. The perforation 301 serves as a pressure balancing channel and can reduce pressure. When the pressure between the two sealing lips 31 is too high, some of the medium flows through the perforation 301 to the surface of the shaft 100, thereby reducing the pressure between the two sealing lips 31. In addition, some of the medium flowing out of the perforation 301 can also lubricate and cool the shaft 100 and the wear ring 300.

[0043] It should be noted that, in order to further improve the pressure reduction effect of the perforation 301, multiple perforations 301 can be provided on the wear ring 300, and the multiple perforations 301 are distributed at equal intervals.

[0044] In this embodiment, as Figure 1 and Figure 6 As shown, an exhaust port 13 is provided on the end plate 1. One end of the exhaust port 13 is connected to the annular groove 12, and the other end is connected to the outside. When the screw pump is working, if the pressure in the sealing area is too high, some high-pressure gas will enter the labyrinth seal and then flow to the outside through the exhaust port 13 to ensure that the pressure in the sealing area is always at a normal level. In addition, when there is a small amount of leaking medium inside the labyrinth seal, it can be discharged through the exhaust port 13 to avoid the medium from accumulating inside the labyrinth seal and affecting the sealing effect.

[0045] In this embodiment, as Figure 1 As shown, a bearing 400 is fixedly installed in the mounting hole 11. A sealing ring is provided between the mating surfaces of the bearing 400 and the mounting hole 11, allowing the bearing 400 to be sealed and installed in the mounting hole 11. The bearing 400 is inserted into the shaft 100 to limit the position of the shaft 100 and prevent the angle of the shaft 100 from shifting. When the rotation of the shaft 100 becomes stuck, lubricating oil can be added to the bearing 400 to make the rotation of the shaft 100 smoother. Specifically, the end of the bearing 400 abuts against the end of the oil baffle ring 4, and the bearing 400 can fix the angle of the oil baffle ring 4 to prevent the oil baffle ring 4 from tilting and reducing the sealing effect of the labyrinth seal.

[0046] Furthermore, such as Figure 1 and Figure 6As shown, a pressure ring 5 is also installed on the end plate 1. The outer contour of the pressure ring 5 is larger than the contour of the mounting hole 11. The inner contour of the pressure ring 5 extends into the mounting hole 11 and fits against the outer ring of the bearing 400, thereby limiting the outer ring of the bearing 400 through the pressure ring 5 to prevent the bearing 5 from shifting position.

[0047] Specifically, such as Figure 1 As shown, a fastener 102 is installed on the shaft 100. The fastener 102 fits against the inner ring of the bearing 400 to limit the inner ring of the bearing 400. After the bearing 400 is installed, the fastener 102 can work with the pressure ring 5 to more reliably limit the bearing 400 as a whole.

[0048] As a supplement, a mutually cooperating connection structure is provided between the fastener 102 and the shaft 100, including but not limited to threaded fit and interference fit.

[0049] It should be noted that the sealing ring, piston ring and sealing ring in this application are all prior art, and those skilled in the art can choose their specifications and models at their own discretion, which will not be elaborated here.

[0050] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A screw pump with a quadruple sealing structure, comprising an end plate (1) and a shaft (100), characterized in that, At least one mounting hole (11) is provided in the end plate (1), the shaft (100) is rotatably mounted in the mounting hole (11), and the shaft (100) is provided with a first sealing mechanism and a second sealing mechanism for forming a sealing area; The first sealing mechanism includes a piston ring seat (2), which is sleeved with the shaft (100). A piston ring is installed on the outer side of the piston ring seat (2), and the piston ring is in close contact with the inner wall of the mounting hole (11). The second sealing mechanism includes a shaft seal (3), which is located near the end of the piston ring seat (2) and sleeved with the shaft (100). The inner wall of the shaft seal (3) is provided with at least one sealing lip (31) for sealing with the shaft (100). An oil baffle ring (4) is fixedly installed on the shaft (100). The outer wall of the oil baffle ring (4) is provided with multiple annular protrusions (41), and the inner wall of the end plate (1) is provided with multiple annular grooves (12). The multiple annular protrusions (41) and multiple annular grooves (12) are staggered to form a labyrinth seal. The end plate (1) is also provided with a through hole (200) aligned with the shaft seal (3). The through hole (200) is filled with buffer gas to form a gas barrier seal. The buffer gas is used to seal the medium in the end plate (1). A wear-resistant ring (300) is fixedly sleeved on the shaft (100), the shaft seal (3) is sleeved with the wear-resistant ring (300), and the sealing lip (31) is tightly fitted with the outer wall of the wear-resistant ring (300); a perforation (301) is provided on the wear-resistant ring (300).

2. The screw pump with a quadruple sealing structure as described in claim 1, characterized in that, The piston ring seat (2) is provided with a plurality of recesses (21), and the piston ring is limited and installed in the recesses (21).

3. The screw pump with a quadruple sealing structure as described in claim 2, characterized in that, A sealing groove (101) is provided on the shaft (100), the sealing groove (101) has an overlapping surface with the piston ring seat (2), and a sealing ring is installed in the sealing groove (101).

4. The screw pump with a quadruple sealing structure as described in claim 1, characterized in that, The number of sealing lips (31) is two, and the two sealing lips (31) are bent in opposite directions. The two sealing lips (31) respectively seal both ends of the shaft seal (3).

5. The screw pump with a quadruple sealing structure as described in claim 1, characterized in that, The end plate (1) is provided with an exhaust hole (13), one end of which is connected to the annular groove (12) and the other end is connected to the outside.

6. The screw pump with a quadruple sealing structure as described in claim 1, characterized in that, A bearing (400) is installed in the mounting hole (11). A sealing ring is installed between the mating surfaces of the bearing (400) and the mounting hole (11). The bearing (400) is inserted into the shaft (100). The end of the bearing (400) abuts against the end of the oil baffle ring (4).

7. The screw pump with a quadruple sealing structure as described in claim 6, characterized in that, A pressure ring (5) is installed on the end plate (1), and part of the pressure ring (5) extends into the mounting hole (11) and fits against the outer ring of the bearing (400).

8. The screw pump with a quadruple sealing structure as described in claim 6, characterized in that, A fastener (102) is installed on the shaft (100), and the fastener (102) is in contact with the inner ring of the bearing (400).

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