Multistage pump axial force balancing system

Abstract

The invention relates to the technical field of multi-stage pumps, and particularly discloses a multi-stage pump axial force balancing system which comprises a water inlet section, a water outlet section and a water outlet section. The water outlet section is provided with a pressure relief cavity; two ends of the balance pipe are respectively communicated with the water inlet section and the pressure relief cavity; the two ends of the middle section are communicated with the water inlet section and the water outlet section respectively, an impeller is arranged on the inner wall of the middle section in a matched mode, a flow blocking cavity and a cover plate cavity are formed in the two sides of the impeller, and when the impeller rotates, hydraulic pressure generated by media in the flow blocking cavity to the impeller and hydraulic pressure generated by media in the cover plate cavity to the impeller are balanced; a balancing drum mounted on the pump shaft; the balance rings are mounted on the water outlet section, and the outer wall of the balance drum is sleeved with the balance rings at intervals; wherein the impellers comprise a plurality of first impellers and a plurality of second impellers, and the cover plate cavity corresponding to the second impellers is communicated with the pressure relief cavity through a gap between the balancing drum and the balancing ring. According to the axial force balancing system of the multi-stage pump, the balancing effect of axial force can be improved, and it is ensured that the multi-stage pump runs safely.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-stage pumps, in particular to an axial force balancing system for a multi-stage pump. Background Art

[0002] The radial area of ​​the impeller front shroud of a multistage pump is smaller than that of the impeller rear shroud and equal to the radial area of ​​the impeller's suction inlet. During operation, the impeller suction inlet pressure is lower than the pressures on the front and rear shrouds, generating axial forces. Multistage pumps achieve high lift by connecting multiple impellers in series, thereby adding impeller lift. This results in even greater axial forces during operation. Currently, multistage pumps use a balancing disc mechanism and impeller balancing holes to balance axial forces. However, when balancing axial forces, the balancing disc mechanism causes the rotor of the multistage pump to move left and right and fails to fully balance axial forces. When balancing axial forces, the balancing holes cause high-pressure liquid from the impeller rear shroud to flow through the balancing holes and into the impeller inlet channel. The high-pressure liquid collides with the fluid flowing into the impeller inlet, disrupting the main flow of liquid into the impeller, creating vortices and localized flow separation. This results in low energy conversion efficiency between the liquid and the impeller. Therefore, further improvements are needed to ensure the safe operation of multistage pumps by balancing axial forces. Summary of the Invention

[0003] The purpose of the present invention is to provide an axial force balancing system for a multi-stage pump, which can improve the balancing effect of the axial force and ensure the safe operation of the multi-stage pump.

[0004] In order to achieve the above object, the present invention provides a multi-stage pump axial force balancing system, comprising:

[0005] In the water inlet section, the water outlet is correspondingly arranged on the inducer;

[0006] The water outlet section has a pressure relief chamber;

[0007] A balance pipe, both ends of which are connected to the water inlet section and the pressure relief chamber respectively;

[0008] The middle section has two ends respectively connected to the water inlet section and the water outlet section. The inner wall of the middle section is provided with an impeller. The two sides of the impeller have a choke cavity and a cover plate cavity. When the impeller rotates, the hydraulic pressure generated by the medium in the choke cavity on the impeller and the hydraulic pressure generated by the medium in the cover plate cavity on the impeller are balanced.

[0009] a balance drum, mounted on the pump shaft; and

[0010] A balancing ring is installed at the water outlet section, and the balancing ring is sleeved on the outer wall of the balancing drum at intervals;

[0011] The impeller includes a plurality of first impellers and a second impeller, the second impeller is close to the water outlet section, and the cover plate cavity corresponding to the second impeller is connected to the pressure relief cavity through the gap between the balance drum and the balance ring.

[0012] In some embodiments, the middle section has a leakage cavity corresponding to the side wall of the first impeller, the leakage cavity and the cover plate cavity are separated by a friction ring and a friction surface, and the leakage cavity is connected to the suction port of the first impeller.

[0013] In some embodiments, a leakage channel is formed between the first impeller and the pump shaft, and the leakage chamber is communicated with the suction port of the first impeller through the leakage channel.

[0014] In some embodiments, the axial width of the leakage cavity is greater than the axial width of the cover plate cavity.

[0015] In some embodiments, a balancing chamber is formed between the second impeller, the balancing ring, the outer friction ring, the inner friction ring, the balancing drum and the pump shaft. The balancing chamber and the cover plate chamber are separated by the outer friction ring and the inner friction ring. The balancing chamber is connected to the pressure relief chamber through the gap between the balancing drum and the balancing ring.

[0016] In some embodiments, the axial width of the balancing cavity is greater than the axial width of the cover plate cavity.

[0017] In some embodiments, the inner wall of the balancing ring has a plurality of annular grooves, and the axial direction of the annular grooves coincides with the axial direction of the balancing ring.

[0018] In some embodiments, a regulating valve is included, and the regulating valve is installed on the balancing pipe.

[0019] In some embodiments, a pressure sensor is included, and the pressure sensor is installed in the balance pipe.

[0020] In some embodiments, the opening of the flow-blocking cavity and the opening of the cover plate cavity are correspondingly arranged on both sides of the outer edge of the impeller.

[0021] The present invention provides a multi-stage pump axial force balancing system, which has the following advantages compared with the prior art:

[0022] The water outlet of the water inlet section is correspondingly arranged on the inducer, and the water outlet section has a pressure relief chamber, and the two ends of the balance pipe are respectively communicated with the water inlet section and the pressure relief chamber, and the two ends of the middle section are respectively communicated with the water inlet section and the water outlet section. The inner wall of the middle section is cooperated with an impeller, and the two sides of the impeller have a choke chamber and a cover plate chamber. When the impeller rotates, the hydraulic pressure generated by the medium in the choke chamber on the impeller and the hydraulic pressure generated by the medium in the cover plate chamber on the impeller are balanced. The balance drum is installed on the pump shaft, and the balance ring is installed on the water outlet section. The balance ring is spaced apart and sleeved on the outer wall of the balance drum. The impeller includes multiple first impellers and a second impeller. The second impeller is close to the water outlet section, and the cover plate chamber corresponding to the second impeller is communicated with the pressure relief chamber through the gap between the balance drum and the balance ring. In this way, the impeller has a balancing effect through the flow-blocking chamber and the cover plate chamber, and the two ends of the balancing pipe are respectively connected to the water inlet section and the pressure relief chamber to achieve circulating flow balanced hydraulic pressure, thereby improving the balancing effect of the axial force and ensuring the safe operation of the multi-stage pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic cross-sectional view of an axial force balancing system for a multi-stage pump according to some embodiments of the present invention.

[0024] Figure 2 A schematic diagram of the enlarged structure of the first impeller of an axial force balancing system of a multi-stage pump provided in some embodiments of the present invention.

[0025] Figure 3 A schematic diagram of the enlarged structure of the second impeller of an axial force balancing system of a multi-stage pump provided in some embodiments of the present invention.

[0026] Figure 4 A schematic diagram of the enlarged structure of a balance ring of an axial force balancing system for a multi-stage pump provided in some embodiments of the present invention.

[0027] In the figure: 1, water inlet section; 2, water outlet section; 21, pressure relief chamber; 3, balance pipe; 31, pressure regulating valve; 62, pressure sensor; 4, middle section; 5, balance drum; 6, balance ring; 61, annular groove; 7, inducer; 8, impeller; 8a, first impeller; 8b, second impeller; 81, choke chamber; 82, cover plate chamber; 83, discharge chamber; 84, suction port; 85, discharge channel; 86, balance chamber; 9, pump shaft. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0029] It should be understood that in the description of this application, the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. 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 this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated, that is, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In addition, unless otherwise specified, "multiple" means two or more.

[0030] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0031] like Figure 1-Figure 4 As shown, the multi-stage pump axial force balancing system of some embodiments of the present invention includes: an inlet section 1, an outlet section 2, a balancing pipe 3, a middle section 4, a balancing drum 5 and a balancing ring 6.

[0032] The water outlet of the water inlet section 1 is correspondingly arranged at the inducer 7. In this way, the inflow of the water inlet section 1 can drive the rotation of the inducer 7, thereby preventing the generation of cavitation.

[0033] The water outlet section 2 has a pressure relief chamber 21. Specifically, the pressure relief chamber 21 is arranged around the pump shaft 9.

[0034] Both ends of the balance pipe 3 are communicated with the water inlet section 1 and the pressure relief chamber 21 respectively.

[0035] The ends of the middle section 4 are connected to the water inlet section 1 and the water outlet section 2, respectively. The inner wall of the middle section 4 is equipped with an impeller 8, with a choke chamber 81 and a cover plate chamber 82 on either side. When the impeller 8 rotates, the hydraulic pressure generated by the medium in the choke chamber 81 on the impeller 8 is balanced with the hydraulic pressure generated by the medium in the cover plate chamber 82. The inner wall of the choke chamber 81 is curved to reduce flow resistance.

[0036] The balance drum 5 is mounted on the pump shaft 9. The balance ring 6 is mounted on the water outlet section 2, and the balance ring 6 is sleeved on the outer wall of the balance drum 5 at intervals.

[0037] In this embodiment, the impeller 8 includes multiple first impellers 8a and second impellers 8b. The second impeller 8b is close to the water outlet section 2. The cover plate cavity 82 corresponding to the second impeller 8b is connected to the pressure relief cavity 21 through the gap between the balance drum 5 and the balance ring 6.

[0038] When the pump shaft 9 drives the impellers 8 to rotate, the medium conveyed by the first impeller 8a flows from high pressure to low pressure into the choke chamber 81. Under the guidance of the choke chamber 81, the medium generates medium choke flow. The high pressure of the medium choke flow reacts on the first impeller 8a, thereby achieving pressure equilibrium between the choke chamber 81 and the cover chamber 82, thereby eliminating the axial force generated by the first impeller 8a. The medium conveyed by the second impeller 8b flows from high pressure to low pressure. Under the guidance of the choke chamber 81, the medium generates medium choke flow. The high pressure of the medium choke flow reacts on the second impeller 8b, thereby achieving pressure equilibrium between the choke chamber 81 and the cover chamber 82, thereby eliminating the axial force generated by the second impeller 8b. Furthermore, the high-pressure medium in the cover chamber 82 corresponding to the second impeller 8b flows into the pressure relief chamber 21 through the gap between the balance drum 5 and the balance ring 6. The medium in the pressure relief chamber 21 is depressurized through the balance pipe 3 and flows into the water inlet section 1 before re-entering the inducer 180, continuously circulating to achieve axial force equilibrium.

[0039] Based on the above-mentioned structural setting, the impeller 8 has a balancing effect through the flow-blocking chamber 81 and the cover plate chamber 82, and the two ends of the balancing pipe 3 are respectively connected to the water inlet section 1 and the pressure relief chamber 21 to achieve circulating flow and balanced hydraulic pressure, thereby improving the balancing effect of the axial force and ensuring the safe operation of the multi-stage pump.

[0040] like Figure 2 As shown, in some embodiments, the middle section 4 has a leakage chamber 83 corresponding to the sidewall of the first impeller 8a. The leakage chamber 83 is separated from the cover plate chamber 82 by a friction ring and a friction surface. The friction ring is mounted on the inner wall of the middle section 4 and is provided on the first impeller 8a. The leakage chamber 83 is connected to the suction port 84 of the first impeller 8a. In this way, if the friction surface or friction ring is damaged due to long-term use and operation of the multi-stage pump, the high-pressure medium in the cover plate chamber 82 will leak. The leaked medium will flow into the leakage chamber 83 and then into the suction port 84 of the first impeller 8a, thereby eliminating the axial force generated by the first impeller 8a caused by the medium in the leakage chamber 83.

[0041] In some embodiments, a leakage channel 85 is formed between the first impeller 8a and the pump shaft 9, and the leakage chamber 83 is connected to the suction port 84 of the first impeller 8a through the leakage channel 85. In this way, the medium in the leakage chamber 83 can smoothly flow into the suction port 84 of the first impeller 8a.

[0042] In some embodiments, the axial width of the drainage cavity 83 is greater than the axial width of the cover plate cavity 82. The drainage cavity 83 is formed by the first impeller 8a being recessed inwardly and cooperating with the middle section 4, which is conducive to fully utilizing the internal volume of the first impeller 8a.

[0043] like Figure 3As shown, in some embodiments, a balancing chamber 86 is formed between the second impeller 8b, the balancing ring 6, the outer friction ring, the inner friction ring, the balancing drum 5, and the pump shaft 9. The balancing chamber 86 is separated from the cover plate chamber 82 by the outer friction ring and the inner friction ring. The balancing chamber 86 communicates with the pressure relief chamber 21 through the gap between the balancing drum 5 and the balancing ring 6. In this way, the high-pressure medium in the cover plate chamber 82 flows into the balancing chamber 86 through the gap between the outer friction ring and the inner friction ring, acts on the balancing drum 5, and flows out through the gap between the balancing drum 5 and the balancing ring 6, thereby eliminating the axial force exerted by the medium in the balancing chamber 86 on the second impeller 8b.

[0044] In some embodiments, the axial width of the balancing cavity 86 is greater than the axial width of the cover plate cavity 82. Specifically, the balancing cavity 86 is formed by the second impeller 8b being recessed inwardly and cooperating with the water outlet section 2, thereby making full use of the internal volume of the second impeller 8b.

[0045] like Figure 4 As shown, in some embodiments, the inner wall of the balance ring 6 has a plurality of annular grooves 61, and the axial direction of the annular grooves 61 coincides with the axial direction of the balance ring 6. In this way, when the medium flows through the gap between the balance ring 6 and the balance drum 5, the flow velocity can be reduced by providing the annular grooves 61.

[0046] like Figure 1 As shown, in some embodiments, a regulating valve 31 is included, and the regulating valve 31 is installed in the balancing pipe 3. In this way, the flow rate of the medium in the balancing pipe 3 can be adjusted by the regulating valve 31.

[0047] like Figure 1 As shown, in some embodiments, a pressure sensor 32 is included, and the pressure sensor 32 is installed in the balance pipe 3. In this way, the medium pressure in the balance pipe 3 can be measured by the pressure sensor 32.

[0048] like Figure 3 and 4 As shown, in some embodiments, the opening of the choke cavity 81 and the opening of the cover plate cavity 82 are correspondingly provided on both sides of the outer edge of the impeller 8. This facilitates the flow of the medium into or out of the choke cavity 81 and the cover plate cavity 82, maintaining the pressure balance on both sides of the impeller 8.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-stage pump axial force balancing system, characterized in that: include: In the water inlet section, the water outlet is correspondingly arranged on the inducer; The water outlet section has a pressure relief chamber; A balance pipe, both ends of which are connected to the water inlet section and the pressure relief chamber respectively; The middle section has two ends respectively connected to the water inlet section and the water outlet section. The inner wall of the middle section is provided with an impeller. The two sides of the impeller have a choke cavity and a cover plate cavity. When the impeller rotates, the hydraulic pressure generated by the medium in the choke cavity on the impeller and the hydraulic pressure generated by the medium in the cover plate cavity on the impeller are balanced. Balance drum, mounted on the pump shaft; as well as A balancing ring is installed at the water outlet section, and the balancing ring is sleeved on the outer wall of the balancing drum at intervals; The impeller includes a plurality of first impellers and a second impeller, the second impeller is close to the water outlet section, and the cover plate cavity corresponding to the second impeller is connected to the pressure relief cavity through the gap between the balance drum and the balance ring.

2. The multi-stage pump axial force balancing system according to claim 1, characterized in that: The middle section has a leakage cavity corresponding to the side wall of the first impeller. The leakage cavity is separated from the cover plate cavity by a friction ring and a friction surface. The leakage cavity is connected to the suction port of the first impeller.

3. The multi-stage pump axial force balancing system according to claim 2, characterized in that: A leakage channel is formed between the first impeller and the pump shaft, and the leakage chamber is communicated with the suction port of the first impeller through the leakage channel.

4. The multi-stage pump axial force balancing system according to claim 2, characterized in that: The axial width of the leakage cavity is greater than the axial width of the cover plate cavity.

5. The multi-stage pump axial force balancing system according to claim 1, characterized in that: A balancing chamber is formed between the second impeller, the balancing ring, the outer friction ring, the inner friction ring, the balancing drum and the pump shaft. The balancing chamber and the cover plate chamber are separated by the outer friction ring and the inner friction ring. The balancing chamber is connected to the pressure relief chamber through the gap between the balancing drum and the balancing ring.

6. The multi-stage pump axial force balancing system according to claim 5, characterized in that: The axial width of the balancing cavity is greater than the axial width of the cover plate cavity.

7. The multi-stage pump axial force balancing system according to claim 1, characterized in that: The inner wall of the balancing ring has a plurality of annular grooves, and the axial direction of the annular grooves coincides with the axial direction of the balancing ring.

8. The multi-stage pump axial force balancing system according to claim 1, characterized in that: It includes a regulating valve, which is installed on the balancing pipe.

9. The multi-stage pump axial force balancing system according to claim 1, characterized in that: A pressure sensor is included, and the pressure sensor is installed on the balance pipe.

10. The multi-stage pump axial force balancing system according to claim 1, characterized in that: The opening of the flow-blocking cavity and the opening of the cover plate cavity are correspondingly arranged on both sides of the outer edge of the impeller.

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