Single balance mechanism of multistage centrifugal pump

Abstract

The utility model provides a single balance mechanism of a multi-stage centrifugal pump. The single balance mechanism comprises a last-stage guide vane, a last-stage impeller, a shaft body, a balance drum, a fixing key, a balance sleeve, a pump cover and a honeycomb throttling groove. The tail-stage impeller is arranged in the tail-stage guide vane, the shaft body is sleeved with the tail-stage impeller, the shaft body is sleeved with the balance drum, the balance drum is located on one side of the tail-stage impeller, the fixing key is arranged between the shaft body and the balance drum, and the balance sleeve is arranged on the outer side of the balance drum. The balancing sleeve has the advantages that the throttling grooves are formed in the balancing sleeve and are of the honeycomb structure, the pressure of internal media can be effectively reduced, the honeycomb face can form more effective hydraulic support for the rotor, the rigidity of the rotor is improved, and the running reliability of the rotor is guaranteed.

Description

Technical Field

[0001] The present application belongs to the technical field of centrifugal pump equipment, and specifically relates to a single balancing mechanism of a multi-stage centrifugal pump. Background Art

[0002] Multistage centrifugal pumps are widely used in many fields such as petroleum, chemical industry, machinery, nuclear power, etc. Axial force balance has always been a key issue in the design of multistage pump solutions. Poor axial force balance will cause overheating or even burning of the thrust bearing, which is one of the common failures of centrifugal pumps and directly affects their lifespan.

[0003] At present, common balancing mechanism designs include single balancing drum, double balancing drum and balancing plate. Compared with the other two, the balancing force of the single balancing drum is more stable, not constrained by the rotor flow, and there will be no dynamic and static contact and grinding and locking. It is more suitable for working occasions such as nuclear power that require higher reliability of multi-stage pump operation, but the stable movement of the rotor still needs to be improved. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art or related technology.

[0005] In order to solve the above problems, the present application provides a single balancing mechanism of a multi-stage centrifugal pump, including: a last-stage guide vane, a last-stage impeller, a shaft body, a balancing drum, a fixing key, a balancing sleeve, a pump cover and a honeycomb throttling groove;

[0006] The last-stage impeller is arranged in the last-stage guide vane, the last-stage impeller is sleeved on the shaft body, the balance drum is sleeved on the shaft body and located on one side of the last-stage impeller, the fixed key is arranged between the shaft body and the balance drum, the balance sleeve is arranged on the outside of the balance drum, a gap is left in the axial direction between the balance sleeve and the balance drum, the pump cover is arranged on the shaft body and located on the outside of the balance sleeve and the last-stage guide vane, and a honeycomb throttling groove is opened on the end surface of the balance sleeve facing the balance drum.

[0007] Optionally, a limiting member is provided on the shaft body for axially limiting the balance drum.

[0008] Optionally, the limiting member includes a locking bolt and a spacer, the spacer is sleeved on the shaft body, and the locking bolt passes through the spacer and is disposed on the shaft body.

[0009] Optionally, a snap ring is further included, wherein the snap ring is arranged between the balancing drum and the shaft body, and the snap ring is located on a side of the balancing drum away from the spacing pad.

[0010] Optionally, a first sealing ring is further included, wherein the first sealing ring is arranged between the balancing drum and the shaft body, and the first sealing ring is located on a side of the balancing drum away from the clamping ring.

[0011] Optionally, fastening bolts are provided between the balancing sleeve and the pump cover.

[0012] Optionally, a second sealing ring is provided between the balancing sleeve and the pump cover.

[0013] Beneficial Effects

[0014] A single balancing mechanism of a multi-stage centrifugal pump provided in an embodiment of the utility model has the following features:

[0015] Beneficial effects:

[0016] 1. By providing a throttling groove on the balancing sleeve, the throttling groove has a honeycomb structure, which can not only effectively reduce the pressure of the internal medium, but also the honeycomb surface can form a more effective hydraulic support for the rotor, increase the rotor stiffness, and ensure the reliability of the rotor operation;

[0017] 2. There is only one axial gap in the entire interior, which is only related to the radial size and is not affected by the rotor movement, making the balancing force of the balancing mechanism more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a front view and cross-sectional structure diagram of a single balancing mechanism of a multi-stage centrifugal pump of the utility model;

[0019] Figure 2 The utility model is a cross-sectional structural diagram of a balancing sleeve of a single balancing mechanism of a multi-stage centrifugal pump.

[0020] The reference numerals are:

[0021] 1. Last stage guide vane; 2. Last stage impeller; 3. Shaft; 4. Balance drum; 5. Fixing key; 6. Balance sleeve; 7. Pump cover; 8. Honeycomb throttling groove; 9. Limiting piece; 91. Locking bolt; 92. Spacer; 10. Snap ring; 11. First sealing ring; 12. Fastening bolt; 13. Second sealing ring. DETAILED DESCRIPTION

[0022] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0024] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0025] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0026] See also Figure 1-2 As shown, according to an embodiment of the present application, a single balancing mechanism of a multistage centrifugal pump is provided, comprising: a last-stage guide vane 1, a last-stage impeller 2, a shaft body 3, a balancing drum 4, a fixing key 5, a balancing sleeve 6, a pump cover 7 and a throttling groove 8; the last-stage impeller 2 is arranged in the last-stage guide vane 1, the last-stage impeller 2 is sleeved on the shaft body 3, the balancing drum 4 is sleeved on the shaft body 3 and is located on one side of the last-stage impeller 2, the fixing key 5 is arranged between the shaft body 3 and the balancing drum 4, the balancing sleeve 6 is arranged on the outside of the balancing drum 4, a gap is left in the axial direction between the balancing sleeve 6 and the balancing drum 4, the pump cover 7 is arranged on the shaft body 3 and is located on the outside of the balancing sleeve 6 and the last-stage guide vane 1, and a honeycomb throttling groove 8 is opened on the end surface of the balancing sleeve 6 facing the balancing drum 4.

[0027] Specifically, the last-stage impeller 2 is connected to the shaft body 3, and the last-stage guide vane 1 is installed on the outside of the last-stage impeller 2. When the shaft body 3 rotates, it can drive the last-stage impeller 2 to rotate. The balancing drum 4 is installed on the shaft body 3 through the fixed key 5, and the balancing drum 4 can rotate with the shaft body 3. The balancing sleeve 6 is sleeved on the outside of the balancing drum 4 and leaves a gap in the axial direction. The balancing sleeve 6 is connected to the pump cover 7. Therefore, the gap between the balancing sleeve 6 and the balancing drum 4 is only related to the radial size, which is not affected by the rotor movement, so that the balancing force is more stable. A number of honeycomb throttling grooves 8 are opened on the end face of the balancing sleeve 6 facing the balancing drum 4. Through the setting of the honeycomb throttling grooves 8, not only can the pressure of the medium inside the gap be effectively reduced, but also the honeycomb surface of the honeycomb throttling grooves 8 can form a more effective hydraulic support for the entire rotor, increase the rotor stiffness, and ensure the reliability of the rotor operation. When the medium flows out from the last-stage impeller 2, it passes through the gap between the balancing sleeve 6 and the balancing drum 4. Under the action of the honeycomb throttling groove 8, the pressure gradually decreases to form a low-pressure cavity, and then returns to the inlet of the pump body through the dedicated channel on the discharge side pump cover 7, completing the entire axial force balance.

[0028] The shaft body 3 is provided with a limiting member 9 for axially limiting the balance drum 4 .

[0029] The limiting member 9 includes a locking bolt 91 and a spacer 92 . The spacer 92 is sleeved on the shaft body 3 . The locking bolt 91 passes through the spacer 92 and is disposed on the shaft body 3 .

[0030] Specifically, the limit member 9 installed on the shaft body 3 can limit the balance drum 4 in the axial direction from the low-pressure side. The limit member 9 includes a locking bolt 91 and a spacer 92. The spacer 92 is fixed to the shaft body 3 by the locking bolt 91, and the size of the spacer 92 can be adjusted, which can be determined according to the final size of each axial part, and can more effectively ensure the effective length between the balance sleeve 6 and the balance drum 4.

[0031] The balancing drum 4 further comprises a snap ring 10 , which is disposed between the balancing drum 4 and the shaft body 3 . The snap ring 10 is located on a side of the balancing drum 4 away from the spacer pad 92 .

[0032] Specifically, the clamping ring 10 is installed between the balance drum 4 and the shaft body 3 to axially fix the balance drum 4 and the shaft body 3 from the high pressure side.

[0033] The first sealing ring 11 is also included. The first sealing ring 11 is arranged between the balancing drum 4 and the shaft body 3 . The first sealing ring 11 is located on a side of the balancing drum 4 away from the clamping ring 10 .

[0034] Specifically, the first sealing ring 11 is installed between the balance drum 4 and the shaft body 3 and close to one side of the spacer 92 to prevent the medium from leaking in the axial direction.

[0035] A fastening bolt 12 is provided between the balancing sleeve 6 and the pump cover 7 .

[0036] Specifically, the fastening bolts 12 are used to fix the pump cover 7 and the balancing sleeve 6, so that an axial gap is formed between the balancing sleeve 6 and the balancing drum 4. By setting the fastening bolts 12, the gap between the balancing sleeve 6 and the balancing drum 4 is only related to the radial dimensions of the balancing sleeve 6 and the balancing drum 4, and is not affected by the rotor movement, so that the balancing force is more stable.

[0037] A second sealing ring 13 is provided between the balancing sleeve 6 and the pump cover 7 .

[0038] Specifically, a second sealing ring 13 is installed at the connection between the pump cover 7 and the balancing sleeve 6 , and the second sealing ring 13 can radially seal between the balancing sleeve 6 and the end cover to prevent the medium from leaking from the high-pressure side to the low-pressure side through the top of the balancing sleeve 6 .

[0039] The first sealing ring 11 and the second sealing ring 13 are both O-rings with stronger sealing performance.

[0040] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A single balancing mechanism of a multistage centrifugal pump, characterized in that: include: A final-stage guide vane (1), a final-stage impeller (2), a shaft (3), a balancing drum (4), a fixing key (5), a balancing sleeve (6), a pump cover (7) and a throttling groove (8); The last-stage impeller (2) is arranged in the last-stage guide vane (1), the last-stage impeller (2) is sleeved on the shaft body (3), the balance drum (4) is sleeved on the shaft body (3) and is located on one side of the last-stage impeller (2), the fixed key (5) is arranged between the shaft body (3) and the balance drum (4), the balance sleeve (6) is arranged on the outside of the balance drum (4), a gap is left between the balance sleeve (6) and the balance drum (4) in the axial direction, the pump cover (7) is arranged on the shaft body (3) and is located on the outside of the balance sleeve (6) and the last-stage guide vane (1), and a honeycomb throttling groove (8) is opened on the end surface of the balance sleeve (6) facing the balance drum (4).

2. The single balancing mechanism of a multistage centrifugal pump according to claim 1, characterized in that: The shaft body (3) is provided with an upper limiting member (9) for axially limiting the balancing drum (4).

3. The single balancing mechanism of a multistage centrifugal pump according to claim 2, characterized in that: The limiting member (9) comprises a locking bolt (91) and a spacer (92); the spacer (92) is sleeved on the shaft body (3); and the locking bolt (91) passes through the spacer (92) and is arranged on the shaft body (3).

4. The single balancing mechanism of the multistage centrifugal pump according to claim 3, characterized in that: It also comprises a snap ring (10), wherein the snap ring (10) is arranged between the balancing drum (4) and the shaft body (3), and the snap ring (10) is located on a side of the balancing drum (4) away from the spacing pad (92).

5. The single balancing mechanism of a multi-stage centrifugal pump according to claim 4, characterized in that: It also comprises a first sealing ring (11), wherein the first sealing ring (11) is arranged between the balancing drum (4) and the shaft body (3), and the first sealing ring (11) is located on a side of the balancing drum (4) away from the clamping ring (10).

6. The single balancing mechanism of the multi-stage centrifugal pump according to claim 5, characterized in that: A fastening bolt (12) is provided between the balancing sleeve (6) and the pump cover (7).

7. The single balancing mechanism of a multi-stage centrifugal pump according to claim 6, characterized in that: A second sealing ring (13) is provided between the balancing sleeve (6) and the pump cover (7).

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