Orifice ring sealing device for impeller water inlet section

Abstract

The present application relates to the technical field of dynamic sealing, in particular to a kind of impeller water inlet section ring seal device, including coaxially arranged in the sealing ring of pump body inside, first rotating collar and second rotating collar, sealing ring is fixedly installed in the side of installation ring seat towards impeller backplate, the outer wall of installation ring seat is attached pump body inner wall, the first rotating collar is rotated along with impeller, and the first inner mounting hole of the first rotating collar's circumference side is slidably installed with first centrifugal slider;Second rotating collar is set outside first rotating collar, and the second inner mounting hole of second rotating collar circumference side is slidably installed with second centrifugal slider;The abutting surface of second centrifugal slider is attached with the abutting surface of installation ring seat, and the centrifugal force generated when the second rotating collar is rotated by impeller drives second centrifugal slider to move radially outwards along second rotating collar and push sealing ring to attach impeller, and the clearance between impeller and pump body is sealed, the resistance to impeller rotation is reduced, and the loss of leakage is reduced.

Description

Technical Field

[0001] This invention relates to the field of dynamic sealing technology, specifically to an impeller inlet ring sealing device. Background Technology

[0002] When a centrifugal pump is running, liquid enters the impeller from the pump body's inlet section and performs work, increasing the liquid's pressure and speed to achieve the pump's conveying function. Since the pump body is static while the impeller rotates at high speed, an appropriate clearance needs to be reserved to ensure impeller operation. If this clearance is too small, the impeller may seize up or easily rust and jam; if it is too large, it will lead to leakage losses, increased wasted work, and decreased pump efficiency.

[0003] Currently, most manufacturers allow for a clearance in the fit, assuming leakage loss. The clearance is 0.25-1.0mm, with 0.5mm being the most common for small-power centrifugal pumps and 1.0mm for large-power pumps. Some have tried adding a mechanical seal, but this puts the pump in a double mechanical seal configuration, which poses a significant challenge for starting the pump, especially since single-phase pumps have relatively low starting torque and are therefore riskier. Summary of the Invention

[0004] To address the aforementioned issues, it is necessary to provide an impeller inlet ring sealing device that addresses the problems of existing technologies.

[0005] To solve the problems of the prior art, the technical solution adopted by the present invention is as follows:

[0006] A sealing device for the inlet ring of an impeller includes a sealing ring, a first rotating collar, and a second rotating collar coaxially disposed inside the pump body. The sealing ring is made of a self-lubricating wear-resistant material and is fixedly installed on the side of a mounting ring seat facing the impeller back plate. The axis of the mounting ring seat is co-lined with the axis of the sealing ring. The outer wall of the mounting ring seat fits against the inner wall of the pump body, and the mounting ring seat can move horizontally along the impeller axis to change the distance between the sealing ring and the impeller back plate. The first rotating collar is coaxially disposed on the impeller and rotates with the impeller. A first inner mounting hole is provided on the circumference of the first rotating collar, and a second rotating collar that moves radially along the first rotating collar is slidably installed in the first inner mounting hole. A centrifugal slider; a second rotating collar is sleeved on the outside of the first rotating collar. The first centrifugal slider slides under centrifugal force and protrudes from the circumference of the mounting ring seat. The first centrifugal slider is connected to the first rotating collar and the second rotating collar. The circumference of the second rotating collar is provided with a plurality of second inner mounting holes. The second centrifugal slider, which moves radially along the second rotating collar, is slidably installed in the second inner mounting holes. The top of the second centrifugal slider is provided with an inclined contact surface. The inner wall of the mounting ring seat is provided with an inclined abutment surface. The contact surface of the second centrifugal slider is in contact with the abutment surface of the mounting ring seat. The second centrifugal slider moves radially outward along the second rotating collar to push the sealing ring to fit against the impeller and seal the gap between the impeller and the pump body.

[0007] Preferably, the inner wall of the second rotating collar is provided with an annular groove, which surrounds the periphery of the first rotating collar. When the top of the first centrifugal slider protrudes from the periphery of the first inner mounting hole, it enters the interior of the annular groove. A protruding baffle is provided inside the annular groove. When the baffle is in contact with the periphery of the first inner mounting hole, the first rotating collar and the second rotating collar rotate synchronously.

[0008] Preferably, the second rotating collar is mounted on the rear end cover of the pump body via a positioning bushing. The axis of the positioning bushing is on the same straight line as the axis of the impeller. A limiting groove is provided on the side of the second rotating collar facing the rear end cover, and the second rotating collar is limited and mounted on the positioning bushing via the limiting groove.

[0009] Preferably, a rotary bearing is provided between the positioning bushing and the limiting groove.

[0010] Preferably, a plurality of balls are rolled on the side of the limiting groove that contacts the positioning bushing. The balls are evenly distributed around the axis of the second rotating collar, and the outer wall of the balls fits the side of the positioning bushing.

[0011] Preferably, the mounting ring seat is provided with at least two guide rods, which extend toward the rear end cover in a direction parallel to the impeller axis; the rear end cover is also provided with a fixing ring, which is provided with a guide hole that is in the same straight line as the axis of the guide rod, and the guide rod is inserted into the guide hole.

[0012] Preferably, a limiting ring is provided at the top of the guide rod, and the diameter of the limiting ring is larger than the diameter of the guide hole; a first elastic element is sleeved on the guide rod, the first elastic element elastically connects the limiting ring and the fixing ring, and the first elastic element applies an elastic force to the mounting ring seat away from the impeller back plate.

[0013] Preferably, a second elastic element is provided in the first inner mounting hole, the second elastic element elastically connects the first inner mounting hole and the first centrifugal slider, and the second elastic element applies elastic force to the first centrifugal slider radially into the first inner mounting hole along the first rotating collar.

[0014] Preferably, a third elastic element is provided in the second inner mounting hole. The third elastic element elastically connects the second inner mounting hole and the second centrifugal slider. The third elastic element applies a spring force to the second centrifugal slider as it enters the second inner mounting hole radially along the second rotating collar.

[0015] The advantages of this invention compared to the prior art are:

[0016] Firstly, in this invention, when the centrifugal pump is not in operation, the sealing ring does not contact the impeller back plate. When the second rotating collar rotates, the second rotating collar drives the second centrifugal slider to move the mounting ring seat forward through centrifugal force. The sealing ring then fits against the impeller back plate to seal. The surface of the impeller back plate rotates relative to the surface of the sealing ring. The sealing ring, which uses self-lubricating and wear-resistant materials, can reduce the resistance to impeller rotation and reduce leakage losses by utilizing its self-lubricating and water-lubricating properties, thereby improving the efficiency of the centrifugal pump.

[0017] Secondly, in this invention, when the drive motor starts, the sealing ring does not contact the impeller back plate. The drive motor only needs to provide power to drive the impeller and the first rotating collar to rotate, which puts less load on the drive motor shaft and is more conducive to the rapid start of the centrifugal pump. After the first rotating collar rotates, the centrifugal force drives the first centrifugal slider to protrude from the circumference of the first rotating collar and enter the annular groove of the second rotating collar. The first centrifugal slider abuts against the baffle to realize the synchronous rotation of the first rotating collar and the second rotating collar.

[0018] Thirdly, the present invention achieves automatic reset of the sealing ring, the first centrifugal slider and the second centrifugal slider after the impeller stops rotating by means of the elastic force of the first elastic element acting on the mounting ring seat, the elastic force of the first centrifugal slider acting on the second elastic element acting on the first centrifugal slider acting on the second centrifugal slider acting on the third elastic element, ensuring the same effect when the equipment is started again. Attached Figure Description

[0019] Figure 1 This is a top view of an impeller inlet ring seal device on a centrifugal pump;

[0020] Figure 2 A type of impeller inlet section ring sealing device that, when not in operation, along... Figure 1 Sectional view of section AA;

[0021] Figure 3 yes Figure 2 A magnified view of section B;

[0022] Figure 4 A type of impeller inlet section ring sealing device that, in the working state, along Figure 1 Sectional view of section AA;

[0023] Figure 5 yes Figure 4 A magnified view of a portion at point C;

[0024] Figure 6 A three-dimensional structural breakdown of an impeller inlet ring sealing device Figure 1 ;

[0025] Figure 7 yes Figure 6 A magnified view of a portion at point D;

[0026] Figure 8 A three-dimensional structural breakdown of an impeller inlet ring sealing device Figure 2 .

[0027] The following are the labels in the diagram: 1. Sealing ring; 11. Mounting ring seat; 111. Abutment surface; 112. Guide rod; 113. Limiting ring; 114. First elastic element; 12. Fixing ring; 121. Guide hole; 2. First rotating collar; 21. First inner mounting hole; 211. First centrifugal slider; 212. Second elastic element; 3. Second rotating collar; 31. Second inner mounting hole; 311. Second centrifugal slider; 312. Contact surface; 313. Third elastic element; 32. Ring groove; 321. Baffle; 33. Positioning bushing; 34. Limiting groove; 341. Rotary bearing; 342. Ball bearing. Implementation

[0028] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0029] Reference Figures 1 to 8 :

[0030] A sealing device for the inlet ring of an impeller includes a sealing ring 1, a first rotating collar 2, and a second rotating collar 3 coaxially disposed inside the pump body. The sealing ring 1 is made of a self-lubricating wear-resistant material and is fixedly installed on the side of the mounting ring seat 11 facing the impeller back plate. The axis of the mounting ring seat 11 is on the same straight line as the axis of the sealing ring 1. The outer wall of the mounting ring seat 11 fits against the inner wall of the pump body. The mounting ring seat 11 can move horizontally along the impeller axis to change the distance between the sealing ring 1 and the impeller back plate. The first rotating collar 2 is coaxially disposed on the impeller and rotates with the impeller. A first inner mounting hole 21 is provided on the circumference of the first rotating collar 2. A first centrifugal slider 211 that moves radially along the first rotating collar 2 is slidably installed in the first inner mounting hole 21. The second rotating collar 3... The rotating collar 3 is sleeved on the outside of the first rotating collar 2. The first centrifugal slider 211 slides under centrifugal force and protrudes from the circumference of the mounting ring seat 11. The first centrifugal slider 211 is connected to the first rotating collar 2 and the second rotating collar 3. The second rotating collar 3 has several second inner mounting holes 31 on its circumference. The second centrifugal slider 311, which moves radially along the second rotating collar 3, is slidably installed in the second inner mounting holes 31. The top of the second centrifugal slider 311 is provided with an inclined contact surface 312. The inner wall of the mounting ring seat 11 is provided with an inclined abutment surface 111. The contact surface 312 of the second centrifugal slider 311 is in contact with the abutment surface 111 of the mounting ring seat 11. The second centrifugal slider 311 moves radially outward along the second rotating collar 3 to push the sealing ring 1 to fit against the impeller and seal the gap between the impeller and the pump body.

[0031] The sealing device in this application is installed inside the pump body. The sealing ring 1 is installed on the mounting ring seat 11, which fits against the inner wall of the pump body and can move along the impeller axis. When the mounting ring seat 11 moves to the point where the sealing ring 1 fits against the impeller back plate, the sealing ring 1 seals the gap between the impeller back plate and the pump body. The sealing device in this application also includes a first rotating collar 2 and a second rotating collar 3. The first rotating collar 2 and the second rotating collar 3 are coaxially arranged with the impeller. The first rotating collar 2 is fixedly connected to the impeller. When the drive motor shaft drives the impeller to rotate, the first rotating collar 2 rotates with the impeller. The second rotating collar 3 is sleeved on the outside of the first rotating collar 2 and does not move synchronously with the impeller. Therefore, when the impeller rotates, it only needs to drive the first rotating collar 2 to rotate, which puts less starting pressure on the drive motor. When the first rotating collar 2 rotates, under the action of centrifugal force, the first inner mounting hole 2 on the periphery of the first rotating collar 2 is closed. The first centrifugal slider 211, which is slidably mounted inside the first rotating collar 2, is thrown out. The first centrifugal slider 211 moves radially along the first rotating collar 2 and protrudes from the circumference of the first rotating collar 2. In this state, the first rotating collar 2 is connected to the second rotating collar 3, which drives the second rotating collar 3 to rotate synchronously with the impeller. Subsequently, the second centrifugal slider 311, which is slidably mounted in the second inner mounting hole 31 on the circumference of the second rotating collar 3, moves radially along the second rotating collar 3 under the action of centrifugal force. The contact surface 312 of the second centrifugal slider 311 is always in contact with the abutment surface 111 on the inner side of the mounting ring seat 11, and both the contact surface 312 and the abutment surface 111 are inclined surfaces. When the second centrifugal slider 311 moves radially along the second rotating collar 3, it will drive the mounting ring seat 11 to move towards the impeller back plate, so that the sealing ring 1, which is not in contact with the impeller back plate in the non-working state, abuts against the impeller back plate to seal the gap between the impeller back plate and the pump body. In this embodiment, the sealing ring 1 can only move horizontally along the impeller axis. Therefore, the sealing ring 1 is made of a self-lubricating wear-resistant material, such as pressed graphite. When the centrifugal pump is not in operation, the sealing ring 1 does not contact the impeller back plate. Therefore, when the drive motor starts, it only needs to provide power to drive the impeller and the first rotating collar 2 to rotate, which puts less load on the drive motor shaft and is more conducive to the rapid start of the centrifugal pump. When the first rotating collar 2 is connected to the second rotating collar 3, the second rotating collar 3 drives the mounting ring seat 11 to move forward through centrifugal force and the second centrifugal slider 311. The sealing ring 1 then fits against the impeller back plate for sealing. The surface of the impeller back plate rotates relative to the surface of the sealing ring 1. The sealing ring 1, which uses a self-lubricating wear-resistant material, can reduce the resistance to impeller rotation and reduce leakage losses by utilizing the properties of self-lubrication and water lubrication, thereby improving the efficiency of the centrifugal pump. In this embodiment, the number of second inner mounting holes 31 on the circumference of the second rotating collar 3 can be set according to actual needs.

[0032] In order to achieve the purpose of drivingly connecting the first rotating collar 2 and the second rotating collar 3 when the first centrifugal slider 211 protrudes from the circumferential surface of the first inner mounting hole 21, the following features are specifically provided:

[0033] The inner wall of the second rotating collar 3 is provided with an annular groove 32, which surrounds the circumference of the first rotating collar 2. When the top end of the first centrifugal slider 211 protrudes from the circumference of the first inner mounting hole 21, it enters the interior of the annular groove 32. A protruding baffle 321 is provided inside the annular groove 32. When the baffle 321 fits against the circumference of the first inner mounting hole 21, the first rotating collar 2 and the second rotating collar 3 rotate synchronously.

[0034] In this embodiment, the second rotating collar 3 is sleeved on the outside of the first rotating collar 2. The inner wall of the second rotating collar 3 is provided with an annular groove 32 along the movement trajectory of the first inner mounting hole 21. When the first rotating collar 2 and the second rotating collar 3 rotate relative to each other, the top opening of the first inner mounting hole 21 always moves along the annular groove 32. When the impeller rotates, it drives the first rotating collar 2 to rotate. Under the action of centrifugal force, the first centrifugal slider 211 on the periphery of the first rotating collar 2 moves radially along the first rotating collar 2 and protrudes from the periphery of the first inner mounting hole 21. At this time, the top end of the first centrifugal slider 211 enters the annular groove 32 provided on the inner wall of the second rotating collar 3 sleeved on the first rotating collar 2. As the first rotating collar 2 continues to rotate, the first centrifugal slider 211 moves radially along the first rotating collar 2 and protrudes from the periphery of the first inner mounting hole 21. The slider 211 moves in the annular groove 32 and eventually contacts the protruding baffle 321 inside the annular groove 32. The side of the first centrifugal slider 211, which is in contact with the side of the baffle 321, will push the baffle 321 to make the second rotating collar 3 and the first rotating collar 2 rotate synchronously. In this embodiment, only one first inner mounting hole 21 is provided on the side of the first rotating collar 2. When the first centrifugal slider 211 protrudes from the side of the first rotating collar 2 inside the first inner mounting hole 21, it maintains a certain stroke in the annular groove 32. This ensures that the first rotating collar 2 is only connected to the second rotating collar 3 after the impeller and the first rotating collar 2 have rotated for a period of time when the drive motor starts. This reduces the torque requirement on the drive motor shaft during startup and facilitates the rapid startup of the equipment.

[0035] To stabilize the position of the second rotating collar 3, the following features are specifically designed:

[0036] The second rotating collar 3 is mounted on the rear end cover of the pump body via a positioning sleeve 33. The axis of the positioning sleeve 33 is on the same straight line as the axis of the impeller. A limiting groove 34 is provided on the side of the second rotating collar 3 facing the rear end cover. The second rotating collar 3 is limited and mounted on the positioning sleeve 33 via the limiting groove 34.

[0037] In this embodiment, the second rotating collar 3 is installed on the rear end cover of the pump body through the positioning bushing 33. The positioning bushing 33 is fixedly installed on the rear end cover to keep the axis of the collar and the axis of the impeller in the same straight line. The second rotating collar 3 is limited and installed on the positioning bushing 33 through the limiting groove 34. The cross-sectional shape of the positioning bushing 33 is sufficient to ensure that the axis of the second rotating collar 3 and its front and rear cannot be offset.

[0038] To reduce the frictional resistance when the second rotating collar 3 rotates with the first rotating collar 2, the following features are specifically provided:

[0039] A rotary bearing 341 is provided between the positioning bushing 33 and the limiting groove 34.

[0040] The rotary bearing 341 provided between the positioning sleeve 33 and the limiting groove 34 ensures the smoothness of the rotation when the second rotary collar 3 rotates with the first rotary collar 2. The rotary bearing 341 can be a common existing technology. The rotary bearing 341 is used to reduce the friction between the periphery of the limiting groove 34 and the periphery of the outer wall of the positioning sleeve 33, thereby reducing the load on the working end of the drive motor after the second rotary collar 3 rotates synchronously with the first rotary collar 2, and avoiding affecting the working efficiency of the centrifugal pump.

[0041] To reduce the frictional resistance when the second rotating collar 3 rotates with the first rotating collar 2, the following features are specifically provided:

[0042] On the side of the limiting groove 34 that contacts the positioning bushing 33, a number of balls 342 are rolled and installed. The balls 342 are evenly distributed around the axis of the second rotating collar 3, and the outer wall of the balls 342 is in contact with the side of the positioning bushing 33.

[0043] In this embodiment, in order to reduce the friction between the upper and lower sides of the limiting groove 34 and the upper and lower sides of the positioning sleeve 33, the limiting groove 34 is provided with several inner grooves on both sides of the positioning sleeve 33, and ball bearings 342 are installed thereon. The surface of the ball bearings 342 is in contact with the positioning sleeve 33, so that the axis of the second rotating collar 3 and the axis of the positioning sleeve 33 are always on the same straight line through the ball bearings 342 on both sides. When the second rotating collar 3 rotates, the sliding friction between the limiting groove 34 and the positioning sleeve 33 is transformed into the rolling friction between the ball bearings 342 and the positioning sleeve 33, which greatly reduces the load on the working end of the drive motor after the second rotating collar 3 rotates synchronously with the first rotating collar 2, and avoids affecting the working efficiency of the centrifugal pump.

[0044] To ensure that the sealing ring 1 can only move in the axial direction of the first rotating collar 2, the following features are specifically designed:

[0045] The mounting ring seat 11 is provided with at least two guide rods 112, which extend toward the rear end cover in a direction parallel to the impeller axis; the rear end cover is also provided with a fixing ring 12, which is provided with a guide hole 121 that is in the same straight line as the axis of the guide rod 112, and the guide rod 112 is inserted into the guide hole 121.

[0046] In this embodiment, a fixing ring 12 is also fixedly installed on the rear end cover. The guide rod 112 provided on the mounting ring seat 11 is inserted into the guide hole 121 provided on the fixing ring 12 to stabilize the axial position of the mounting ring seat 11 and ensure that the mounting ring seat 11 can only drive the sealing ring 1 to move along the axis of the guide rod 112. When the second centrifugal slider 311 of the second rotating collar 3 moves radially outward along the second rotating collar 3 under centrifugal action, the second centrifugal slider 311 pushes the mounting ring seat 11. The abutting surface 111 of the mounting ring seat 11 moves along the contact surface 312 of the second centrifugal slider 311, so that the mounting ring seat 11 moves along the axis of the guide rod 112 until the sealing ring 1 is in contact with the impeller back plate. As the drive motor continues to work, the second inner mounting hole 31 of the second rotating collar 3 maintains the seal of the sealing ring 1 on the gap between the impeller back plate and the pump body under the action of centrifugal force.

[0047] To ensure that the sealing ring 1 automatically releases its contact with the impeller back plate after the impeller stops rotating, the following features are specifically designed:

[0048] The top end of the guide rod 112 is provided with a limiting ring 113, the diameter of the limiting ring 113 is larger than the diameter of the guide hole 121; a first elastic element 114 is sleeved on the guide rod 112, the first elastic element 114 elastically connects the limiting ring 113 and the fixing ring 12, and the first elastic element 114 applies an elastic force to the mounting ring seat 11 away from the impeller back plate.

[0049] In this embodiment, the first elastic element 114 sleeved on the guide rod 112 elastically connects one side of the fixing ring 12 and the limiting ring 113 at the top of the guide rod 112. The first elastic element 114 can be a spring. The first elastic element 114 applies a spring force to the mounting ring seat 11 away from the impeller back plate. When the second rotating collar 3 rotates, the second centrifugal slider 311 pushes the mounting ring seat 11 and the sealing ring 1 closer to the impeller back plate under the action of centrifugal force. At this time, the movement of the mounting ring seat 11 compresses the first elastic element 114. When the impeller stops rotating, the second centrifugal slider 311 loses the support of centrifugal force, and the spring force of the first elastic element 114 causes the sealing ring 1 to return to a state away from the impeller back plate, thereby reducing the starting pressure of the drive motor rotating shaft when the centrifugal pump starts next time.

[0050] In order to achieve the automatic disengagement of the transmission connection between the first centrifugal slider 211 and the second rotating collar 3 after the impeller stops rotating, the following features are specifically designed:

[0051] A second elastic element 212 is provided inside the first inner mounting hole 21. The second elastic element 212 elastically connects the first inner mounting hole 21 and the first centrifugal slider 211. The second elastic element 212 applies elastic force to the first centrifugal slider 211 as it enters the first inner mounting hole 21 radially along the first rotating collar 2.

[0052] In this embodiment, a second elastic element 212 is provided in the first inner mounting hole 21. The second elastic element 212 can be a spring or a sheet, etc. When the first rotating collar 2 rotates, the first centrifugal slider 211 compresses the second elastic element 212 under centrifugal action, causing the first centrifugal slider 211 to move outward. The first centrifugal slider 211 protrudes from the circumference of the first rotating collar 2 and is connected to the second rotating collar 3. When the impeller stops rotating, the centrifugal force disappears, and the first centrifugal slider 211 resets under the elastic force of the second elastic element 212, automatically disengaging the transmission connection between the first rotating collar 2 and the second rotating collar 3, thereby reducing the starting pressure of the drive motor rotating shaft when the centrifugal pump starts next time.

[0053] To achieve the goal of automatically resetting the second centrifugal slider 311 after the second rotating collar 3 stops rotating, the following features are specifically designed:

[0054] A third elastic element 313 is provided in the second inner mounting hole 31. The third elastic element 313 elastically connects the second inner mounting hole 31 and the second centrifugal slider 311. The third elastic element 313 applies elastic force to the second centrifugal slider 311 as it enters the second inner mounting hole 31 radially along the second rotating collar 3.

[0055] In this embodiment, a third elastic element 313 is provided in the second inner mounting hole 31. The third elastic element 313 can be a spring or a sheet, etc. When the second rotating collar 3 rotates, the second centrifugal slider 311 compresses the third elastic element 313 under centrifugal action, causing the first centrifugal slider 211 to move outward and push the mounting ring seat 11 to make the sealing ring 1 fit against the impeller back plate. When the transmission connection between the first rotating collar 2 and the second rotating collar 3 is released, the second rotating collar 3 stops rotating, the centrifugal force disappears, the second centrifugal slider 311 resets under the elastic force of the third elastic element 313, and the sealing ring 1 resets under the elastic force of the first elastic element 114 and the third elastic element 313, releasing the seal on the gap between the impeller back plate and the pump body, and reducing the starting pressure of the drive motor rotating shaft when the centrifugal pump starts next time.

[0056] Working principle: When the drive motor shaft drives the impeller to rotate, the first rotating collar 2 rotates with the impeller. The second rotating collar 3 is sleeved on the outside of the first rotating collar 2 and does not move synchronously with the impeller. Under the action of centrifugal force, the first centrifugal slider 211, which is slidably installed in the first inner mounting hole 21 on the periphery of the first rotating collar 2, is thrown out. The first centrifugal slider 211 moves in the annular groove 32 of the second rotating collar 3 and abuts against the baffle 321, so that the second rotating collar 3 rotates synchronously with the impeller. Subsequently, the second centrifugal slider 311, which is slidably installed in the second inner mounting hole 31 on the periphery of the second rotating collar 3, moves radially along the second rotating collar 3 under the action of centrifugal force. When the second centrifugal slider 311 moves radially along the second rotating collar 3, it will drive the mounting ring seat 11 to move towards the impeller back plate side, so that the sealing ring 1, which is not in contact with the impeller back plate in the non-working state, abuts against the impeller back plate to seal the gap between the impeller back plate and the pump body.

[0057] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A sealing device for the inlet ring of an impeller, characterized in that, It includes a sealing ring (1), a first rotating collar (2), and a second rotating collar (3) that are coaxially arranged inside the pump body. The sealing ring (1) is made of self-lubricating wear-resistant material. The sealing ring (1) is fixedly installed on the side of the mounting ring seat (11) facing the impeller back plate. The axis of the mounting ring seat (11) and the axis of the sealing ring (1) are on the same straight line. The outer wall of the mounting ring seat (11) fits against the inner wall of the pump body. The mounting ring seat (11) can move horizontally along the impeller axis to change the distance between the sealing ring (1) and the impeller back plate. The first rotating collar (2) is coaxially mounted on the impeller. The first rotating collar (2) rotates with the impeller. The first inner mounting hole (21) is provided on the circumference of the first rotating collar (2). A first centrifugal slider (211) that moves radially along the first rotating collar (2) is slidably mounted in the first inner mounting hole (21). The second rotating collar (3) is sleeved on the outside of the first rotating collar (2). The first centrifugal slider (211) slides under centrifugal force and protrudes from the circumference of the mounting ring seat (11). The first centrifugal slider (211) is connected to the first rotating collar (2) and the second rotating collar (3). The second rotating collar (3) has several second inner mounting holes (31) on its circumference. The second centrifugal slider (311) that moves radially along the second rotating collar (3) is slidably installed in the second inner mounting holes (31). The second centrifugal slider (311) has an inclined contact surface (312) at the top, and the inner wall of the mounting ring seat (11) has an inclined abutment surface (111). The contact surface (312) of the second centrifugal slider (311) is in contact with the abutment surface (111) of the mounting ring seat (11). The second centrifugal slider (311) moves radially outward along the second rotating collar (3) to push the sealing ring (1) to fit the impeller and seal the gap between the impeller and the pump body.

2. The impeller inlet section sealing device according to claim 1, characterized in that, The inner wall of the second rotating collar (3) is provided with an annular groove (32), which surrounds the periphery of the first rotating collar (2). When the top of the first centrifugal slider (211) protrudes from the periphery of the first inner mounting hole (21), it enters the interior of the annular groove (32). A protruding baffle (321) is provided in the annular groove (32). When the baffle (321) fits against the circumference of the first inner mounting hole (21), the first rotating collar (2) and the second rotating collar (3) rotate synchronously.

3. The impeller inlet section sealing device according to claim 2, characterized in that, The second rotating collar (3) is installed on the rear end cover of the pump body through the positioning sleeve (33). The axis of the positioning sleeve (33) is on the same straight line as the axis of the impeller. The second rotating collar (3) is provided with a limiting groove (34) on the side facing the rear end cover. The second rotating collar (3) is limited and installed on the positioning sleeve (33) through the limiting groove (34).

4. The impeller inlet section sealing device according to claim 3, characterized in that, A rotary bearing (341) is provided between the positioning bushing (33) and the limiting groove (34).

5. The impeller inlet section sealing device according to claim 3, characterized in that, On the side of the limiting groove (34) that contacts the positioning bushing (33), several balls (342) are rolled and installed. The balls (342) are evenly distributed around the axis of the second rotating collar (3), and the outer wall of the balls (342) is in contact with the side of the positioning bushing (33).

6. The impeller inlet section sealing device according to claim 1, characterized in that, The mounting ring seat (11) is provided with at least two guide rods (112), which extend toward the rear end cover in a direction parallel to the impeller axis. A retaining ring (12) is also provided on the rear end cover. The retaining ring (12) has a guide hole (121) that is on the same straight line as the axis of the guide rod (112). The guide rod (112) is inserted into the guide hole (121).

7. The impeller inlet section sealing device according to claim 6, characterized in that, The top end of the guide rod (112) is provided with a limiting ring (113), the diameter of which is larger than the diameter of the guide hole (121); A first elastic element (114) is sleeved on the guide rod (112). The first elastic element (114) elastically connects the limiting ring (113) and the fixing ring (12). The first elastic element (114) applies an elastic force to the mounting ring seat (11) away from the impeller back plate.

8. The impeller inlet section sealing device according to claim 1, characterized in that, A second elastic element (212) is provided in the first inner mounting hole (21). The second elastic element (212) elastically connects the first inner mounting hole (21) and the first centrifugal slider (211). The second elastic element (212) applies elastic force to the first centrifugal slider (211) radially entering the first inner mounting hole (21) along the first rotating collar (2).

9. The impeller inlet section sealing device according to claim 1, characterized in that, A third elastic element (313) is provided in the second inner mounting hole (31). The third elastic element (313) elastically connects the second inner mounting hole (31) and the second centrifugal slider (311). The third elastic element (313) applies elastic force to the second centrifugal slider (311) radially entering the second inner mounting hole (31) along the second rotating collar (3).

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