A multi-stage pump axial force bearing structure

Abstract

The present invention discloses a multi-stage pump axial force bearing structure, including: a pump shaft and a multi-stage impeller assembly, the pump shaft is arranged on a bearing seat, the multi-stage impeller assembly is sleeved on the pump shaft, each stage of the impeller assembly is provided with an impeller and a guide vane, and the guide vane is floatingly arranged on the pump shaft; the lower end of the first-stage impeller in the multi-stage impeller assembly is provided with a lower retaining spring for limiting; the floating sleeve of the last-stage guide vane in the multi-stage impeller assembly is arranged on the upper end of the pump shaft, and the upper end of the last-stage guide vane is provided with an upper retaining spring and an adjusting sleeve for limiting. In the present invention, the impeller assembly includes an impeller and a guide vane, and the guide vane is floatingly arranged on the pump shaft, so that the axial force generated by the impeller is floatingly borne by the guide vane, and the axial force is prevented from being loaded on the motor shaft; the first-stage impeller and the last-stage guide vane are limited by the upper retaining spring, the lower retaining spring and the adjusting sleeve respectively, and the axial force of the first-stage impeller is transmitted to the last-stage guide vane through the pump shaft, and is borne by the last-stage guide vane, so as to achieve the balance of the axial force and meet the use needs of centrifugal pumps with different structures.

Description

Technical Field

[0001] The invention relates to the technical field of multi-stage pumps, and in particular to an axial force bearing structure of a multi-stage pump. Background Art

[0002] A multistage centrifugal pump is a combination of two or more centrifugal pumps with the same function. In terms of fluid channel structure, the medium pressure relief port of the first stage is connected to the medium inlet of the second stage, and the medium pressure relief port of the second stage is connected to the inlet of the third stage, forming a multistage centrifugal pump in series. Multistage centrifugal pumps can meet different requirements by changing the number of pump stages (number of impellers), so they have a wide range of applications. However, as the number of stages increases, the problem of large axial force in multistage centrifugal pumps increases. Methods for balancing axial force include balancing with thrust bearings, balancing with back blades, balancing with double suction impellers, balancing with symmetrical distribution of impellers, balancing with balancing drums, etc. Among them, balancing with thrust bearings is the most effective, but the axial force of multistage pumps is large, and using thrust bearings to balance the axial force will make the structure of the pump very complicated.

[0003] To this end, Chinese utility model patent CN205895628U provides a high-lift multi-stage deep well submersible pump, including a pump body, a motor and a barrel, an oil cup is arranged at the bottom of the barrel, the oil cup is fixed by a retaining spring, the motor is arranged above the barrel, the pump body is arranged on the motor, the pump body includes a pump head, an upper end, a connecting part and a lower end, a transmission shaft running through the upper end, the connecting part and the lower end is arranged in the pump body, the upper end and the lower end are respectively provided with a plurality of groups of impeller assemblies, and the number of the impeller assemblies at the upper end is greater than the number of the impeller assemblies at the lower end, and a bracket is arranged in the connecting part. The high-lift multi-stage deep well submersible pump energizes the motor through the control box to rotate the motor shaft, and the motor shaft drives the transmission shaft to rotate through the coupling to rotate the impeller, and the liquid flows upward with the impeller level by level. At this time, the impeller will generate a downward push and pull, wherein the thrust generated by the impeller at the upper end is offset by the bracket in the connecting part, and the thrust generated by the impeller at the lower end is offset by the bearing seat, and the stable operation of the deep well submersible pump is achieved by arranging multiple groups of impeller assemblies in sections.

[0004] However, the above-mentioned high-lift multi-stage deep well submersible pump has the following disadvantages:

[0005] (1) The pump body is arranged above the motor, and the motor shaft is connected to the pump shaft through a coupling. In actual operation, the motor shaft bears part of the axial force on the pump shaft. This bearing structure is only applicable to vertical multi-stage submersible pumps with the pump body arranged above the motor, and cannot be applied to inverted submersible pumps or horizontal centrifugal pumps with the motor arranged above the pump body;

[0006] (2) The impeller assemblies are respectively arranged in the upper end and the lower end, and the number of impeller assemblies at the upper end is greater than the number of impeller assemblies at the lower end. There are certain requirements on the number and distribution of impeller assemblies, and it cannot be applied to impeller assemblies of different numbers.

[0007] In view of this, there is an urgent need to improve the axial force bearing structure of the existing multi-stage pump to be suitable for an inverted submersible pump or a horizontal centrifugal pump to meet the needs of different impeller assemblies. Summary of the invention

[0008] The technical problem to be solved by the present invention is that the existing multi-stage pump axial force bearing structure cannot be applied to an inverted or horizontal pump structure.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0010] A multi-stage pump axial force bearing structure, comprising:

[0011] A pump shaft is arranged on the bearing seat, and an upper end of the pump shaft is used to be connected to the motor shaft through a coupling;

[0012] A multi-stage impeller assembly is sleeved on the pump shaft, each stage of the impeller assembly comprises an impeller and a guide vane, and the guide vane is floatingly arranged on the pump shaft;

[0013] The first-stage impeller in the multi-stage impeller assembly is sleeved on the lower end of the pump shaft, and the lower end of the first-stage impeller is provided with a lower retaining spring for limiting position;

[0014] The last-stage guide vane in the multi-stage impeller assembly is floatingly arranged on the upper end of the pump shaft, and the upper end of the last-stage guide vane is provided with a retaining spring and an adjusting sleeve for limiting.

[0015] In this solution, the pump shaft is a prismatic shaft.

[0016] In this solution, the upper end and the lower end of the pump shaft are provided with retaining spring grooves, and the upper retaining spring and the lower retaining spring are arranged in the retaining spring grooves.

[0017] In this solution, the adjusting sleeve includes:

[0018] A lower shaft sleeve is arranged opposite to the upper end of the last-stage guide vane and has a floating space with the outer side surface of the pump shaft;

[0019] The upper shaft sleeve is arranged at the upper end of the lower shaft sleeve and is matched with the outer side surface of the pump shaft.

[0020] In this solution, the pump shaft is arranged on the bearing seat through a sleeve assembly, and the sleeve assembly includes:

[0021] Two inner sleeves are sleeved on the upper and lower ends of the pump shaft, and are respectively arranged between the lower retaining spring and the first-stage impeller, and between the upper retaining spring and the coupling, and the inner sleeves are adapted to the outer side surface of the pump shaft;

[0022] The two outer shaft sleeves are respectively sleeved on the two inner shaft sleeves and matched with the bearing seat and the inner shaft sleeves.

[0023] In this solution, the inner sleeve is an insert made of wear-resistant hard alloy.

[0024] In this solution, the impeller assembly further includes:

[0025] The impeller shell comprises an impeller upper cover and an impeller seat. A guide vane installation position is arranged in the impeller seat. The lower end of the guide vane is inserted into the guide vane installation position. The impeller is arranged between the guide vane and the impeller seat.

[0026] In this solution, the impeller is a closed impeller, including a hub, a wheel disc and a wheel cover arranged on the hub, and blades are arranged between the wheel disc and the wheel cover; the wheel is adapted to the outer side surface of the pump shaft.

[0027] In this solution, a spline groove is provided on the top surface of the coupling for connecting with the motor shaft; and a prismatic groove is provided on the bottom end of the coupling for connecting with the pump shaft.

[0028] In this solution, the adjusting sleeve and the impeller assemblies at each stage are connected in series on the pump shaft, and there is an axial stringing distance between the adjusting sleeve and the impeller assemblies at each stage, and the stringing distance is 0.5-2mm.

[0029] Compared with the prior art, the multi-stage pump axial force bearing structure provided by the present invention includes a pump shaft and a multi-stage impeller assembly sleeved on the pump shaft, each stage of the impeller assembly is provided with an impeller and a guide vane, and the guide vane is floatingly arranged on the pump shaft, so that the axial force generated by each stage of the impeller assembly is transmitted to the guide vane, and the guide vane is floatingly supported, so as to avoid the axial force from being loaded on the motor shaft through the pump shaft; the first stage impeller is limited by the lower retaining spring, and the last stage guide vane is limited by the upper retaining spring, so that the axial force of the first stage impeller is transmitted to the pump shaft through the sleeve and the lower retaining spring structure, and is transmitted to the last stage impeller through the upper retaining spring and the adjusting sleeve, and is floatingly supported by the last stage impeller to achieve axial force balance. The number of stages of the impeller assembly in the present invention is not limited by its own structure, and multiple groups can be connected in series, which can meet the use requirements of different stages of vertical, horizontal, and inverted centrifugal pump structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a cross-sectional view of the load-bearing structure of the present invention;

[0031] Figure 2 It is a schematic diagram of the structural decomposition of the bearing structure in the present invention;

[0032] Figure 3 It is a structural schematic diagram of the impeller assembly in the present invention;

[0033] Figure 4It is a schematic diagram of the structure of the first-stage impeller and the last-stage guide vane in the present invention.

[0034] in, Figures 1 to 4 The corresponding relationship between the reference numerals and component names is as follows:

[0035] 1 pump shaft, 2 impeller assembly, 11 coupling, 12 spline groove, 13 prismatic groove, 14 retaining ring groove, 21 impeller upper cover, 22 impeller seat, 23 impeller, 24 guide vane, 221 impeller mounting position, 231 hub, 232 wheel disc, 233 wheel cover, 234 blade, 25 first-stage impeller, 26 last-stage guide vane, 27 lower retaining ring, 28 upper retaining ring, 29 adjusting sleeve, 291 lower sleeve, 292 upper sleeve, 10 bearing seat, 15 inner sleeve, 16 outer sleeve. DETAILED DESCRIPTION

[0036] The present invention provides a multi-stage pump axial force bearing structure, including a pump shaft and multiple impeller assemblies, the impeller assembly including an impeller and a guide vane floatingly arranged on the pump shaft, the first-stage impeller is limited by a lower retaining spring, and the last-stage guide vane is limited by an upper retaining spring and an adjusting sleeve, so that the first-stage impeller transmits the axial force to the last-stage guide vane through the pump shaft, and the guide vane is floatingly loaded, so that the axial force is balanced, and it is suitable for different multi-stage centrifugal pump structures. The present invention is described in detail below in conjunction with the drawings and specific embodiments of the specification.

[0037] like Figure 1 , Figure 2 As shown, the present invention provides a multi-stage pump axial force bearing structure comprising a pump shaft 1 and a multi-stage impeller assembly 2 , wherein the multi-stage impeller assembly 2 is sleeved on the pump shaft 1 .

[0038] like Figure 3 and Figure 4 As shown, the pump shaft 1 is a prismatic shaft. The upper end of the pump shaft 1 is connected to the motor shaft through a coupling 11. A spline groove 12 is provided on the top surface of the coupling 11 for connecting the motor shaft. A prismatic groove 13 is provided on the bottom surface of the coupling 11. The upper end of the pump shaft 1 is inserted into the prismatic groove 13 and connected to the coupling 11. A retaining ring groove 14 is provided on the upper and lower ends of the pump shaft 1.

[0039] Each impeller assembly 2 includes an impeller housing composed of an impeller upper cover 21 and an impeller seat 22, and an impeller 23 and a guide vane 24 arranged in the impeller housing. A guide vane mounting position 221 is arranged in the impeller seat 22, and the lower end of the guide vane 24 is inserted in the guide vane mounting position 221, and the impeller 23 is arranged between the guide vane 24 and the impeller seat 22.

[0040] The impeller 23 is a closed impeller, including a hub 231, a wheel disc 232 and a wheel cover 233 arranged on the hub 231, a blade 234 is arranged between the wheel disc 232 and the wheel cover 233, and a drainage hole is arranged on the bottom surface of the wheel disc 232. Water enters the wheel disc 232 and the wheel cover 233 through the guide vane 24, and flows out from the drainage hole after being pressurized by the rotation of the blade 234. The hub 231 is adapted to the outer side of the pump shaft 1.

[0041] The guide vane 24 is floatingly sleeved on the pump shaft 1 , and there is a floating space between the guide vane 24 and the outer side surface of the pump shaft 1 , so that the guide vane 24 can float and bear the axial force.

[0042] The first-stage impeller 25 and the last-stage guide vane 26 in the multi-stage impeller assembly are respectively arranged at the upper and lower ends of the pump shaft 1. The first-stage impeller 25 is limited by the lower retaining spring 27, and the last-stage guide vane 26 in the multi-stage impeller assembly is limited by the upper retaining spring 28 and the adjusting sleeve 29, so that the last-stage guide vane 26 is floatingly arranged at the lower end of the pump shaft 1, and the lower retaining spring 27 and the upper retaining spring 28 are respectively arranged in the retaining spring groove 14.

[0043] The adjusting sleeve 29 is arranged between the top surface of the last-stage guide vane 26 and the bottom surface of the upper retaining ring 28, and includes a lower sleeve 291 and an upper sleeve 292. The lower sleeve 290 is arranged opposite to the upper end of the last-stage guide vane 26, and there is a floating space with the outer side surface of the pump shaft 1. The upper sleeve 292 is arranged at the upper end of the lower sleeve 291 and is adapted to the outer side surface of the pump shaft 1. The adjusting sleeve 29 and the impeller assemblies 2 of each stage are connected in series on the pump shaft 1, and there is an axial stringing spacing between the adjusting sleeve 29 and the impeller assemblies 2 of each stage, and the stringing spacing is 0.5-2mm.

[0044] The pump shaft 1 is arranged on the bearing seat 10 through a sleeve assembly. The bearing assembly includes two inner sleeves 15 and two outer sleeves 16. The inner sleeves 15 are sleeved on the upper and lower ends of the pump shaft 1, respectively arranged between the lower retaining spring 27 and the first-stage impeller 25, and between the upper retaining spring 28 and the coupling 11. The inner sleeves 15 are adapted to the outer side of the pump shaft 1. The outer sleeves 16 are sleeved on the inner sleeves 15 respectively, and cooperate with the bearing seat 10 and the inner sleeves 15 at the same time.

[0045] The working principle of the present invention is as follows:

[0046] The pump shaft 1 drives the impeller assembly 2 to rotate under the drive of the motor. During the rotation of the impeller 23, the asymmetric pressure of the wheel cover 233 on the impeller 23 generates an axial force. For the first-stage impeller 25, the lower end of the first-stage impeller 25 is limited by the lower retaining spring 27, and the first-stage impeller 25 can transmit the axial force to the pump shaft 1; at the same time, since the upper retaining spring 28 and the adjusting sleeve 29 are arranged above the last-stage guide vane 26, and the last-stage guide vane 26 is limited by the upper retaining spring 28 and the adjusting sleeve 29, the axial force on the pump shaft 1 can be transmitted to the last-stage guide vane 29, and the last-stage guide vane 29 is floatingly carried. For other impeller assemblies at each stage, the hub 231 on the impeller 23 at each stage is adapted to the outer side surface of the pump shaft 1, and the axial force on the impeller 23 can be transmitted to the pump shaft 1 through the hub 231. Since the guide vanes 24 at each stage are floatingly arranged on the pump shaft 1, the guide vanes 24 can float to bear the axial force. In this way, for the entire multi-stage pump axial force bearing structure, no axial force will be transmitted to the motor shaft through the pump shaft 1, thereby achieving axial force balance.

[0047] Compared with the prior art, the multi-stage pump axial force bearing structure provided by the present invention is provided with multiple groups of impeller assemblies, each group of impeller assemblies includes an impeller and a guide vane, the impeller is sleeved on the pump shaft, and its hub is adapted to the outer side surface of the pump shaft. There is a floating space between the guide vane and the outer side surface of the pump shaft. The guide vane is floatingly arranged on the pump shaft, which can bear the axial force generated by the rotation of the impeller, and avoid the axial force being transmitted to the motor shaft through the pump shaft, so that the motor shaft is worn due to the bearing of the axial force, affecting its service life. Compared with the traditional floating impeller structure, in the present invention, the axial force bearing structure is only the hub of the impeller and the guide vane, and the radial size of the bearing structure is small, so that a low linear speed can be maintained under high-speed operation conditions, avoiding the stage efficiency reduction or stress increase caused by the increase of the Mach number of the airflow due to the excessive linear speed of the impeller, and extending the service life of the impeller and the guide vane.

[0048] In the present invention, multiple impeller assemblies include a first-stage impeller and a last-stage guide vane. The lower end of the first-stage impeller is limited by a lower retaining spring, and the upper end of the last-stage guide vane is limited by an upper retaining spring and an adjusting sleeve, so that the first-stage impeller transmits the generated axial force to the pump shaft, which is then transmitted to the last-stage guide vane through the pump shaft. The last-stage guide vane is floatingly loaded, and the motor shaft does not bear the axial load. The present invention can be applicable to vertical, horizontal or inverted multi-stage centrifugal pumps, and the number of impeller assemblies can be set according to actual needs to meet the use requirements of the working conditions.

[0049] In the present invention, the inner sleeve adopts an insert structure, and the material is wear-resistant hard alloy, which has impact resistance and local high temperature resistance, and can adapt to local friction heating and serial operation conditions of the multi-stage pump during the start-stop process.

[0050] In the present invention, there is axial stringing space between the impellers of each stage, which facilitates the automatic adjustment of the impeller position of each stage according to the pressurized medium to avoid jamming.

[0051] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone should be aware that any structural changes made under the inspiration of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention.

Claims

1. A multi-stage pump axial force bearing structure, characterized in that: include: A pump shaft is arranged on the bearing seat, and an upper end of the pump shaft is used to be connected to the motor shaft through a coupling; A multi-stage impeller assembly is sleeved on the pump shaft, each stage of the impeller assembly comprises an impeller and a guide vane, and the guide vane is floatingly sleeved on the pump shaft; The first-stage impeller in the multi-stage impeller assembly is sleeved on the lower end of the pump shaft, and the lower end of the first-stage impeller is provided with a lower retaining spring for limiting position; The last-stage guide vane in the multi-stage impeller assembly is floatingly arranged on the upper end of the pump shaft, and the upper end of the last-stage guide vane is provided with an upper retaining spring and an adjusting sleeve for limiting position; The pump shaft is a prismatic shaft, and the upper and lower ends of the pump shaft are provided with retaining ring grooves, and the upper retaining ring and the lower retaining ring are arranged in the retaining ring grooves; The adjusting sleeve comprises: A lower shaft sleeve is arranged opposite to the upper end of the last-stage guide vane and has a floating space with the outer side surface of the pump shaft; An upper sleeve, arranged at the upper end of the lower sleeve and adapted to the outer side surface of the pump shaft; The pump shaft is arranged on the bearing seat through a shaft sleeve assembly, and the shaft sleeve assembly comprises: Two inner sleeves are sleeved on the upper and lower ends of the pump shaft, and are respectively arranged between the lower retaining spring and the first-stage impeller, and between the upper retaining spring and the coupling, and the inner sleeves are adapted to the outer side surface of the pump shaft; Two outer sleeves are respectively sleeved on the two inner sleeves and matched with the bearing seat and the inner sleeves; The impeller assembly also includes: An impeller shell, comprising an impeller upper cover and an impeller seat, wherein a guide vane mounting position is provided in the impeller seat, and the lower end of the guide vane is inserted into the guide vane mounting position, and the impeller is arranged between the guide vane and the impeller seat; The impeller is a closed impeller, comprising a hub, a wheel disc and a wheel cover arranged on the hub, and blades are arranged between the wheel disc and the wheel cover; the hub is adapted to the outer side surface of the pump shaft; The top end of the coupling is provided with a spline groove for connecting with the motor shaft, and the bottom end of the coupling is provided with a prismatic groove for connecting with the pump shaft; The adjusting sleeve and the impeller assemblies at each stage are connected in series on the pump shaft. An axial stringing spacing exists between the adjusting sleeve and the impeller assemblies at each stage, and the stringing spacing is 0.5-2 mm.

2. The bearing structure according to claim 1, characterized in that: The inner shaft sleeve is an insert made of wear-resistant hard alloy.

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