Long-shaft double-suction centrifugal pump

Abstract

The invention belongs to the field of centrifugal pump design, and discloses a long-shaft double-suction centrifugal pump which comprises an upper pump assembly, a lower pump assembly, an oil conveying pipe, a permanent magnet motor and a connecting pipe, the upper pump assembly and the lower pump assembly are arranged at the upper end and the lower end of the permanent magnet motor and the upper end and the lower end of the connecting pipe respectively, and the upper pump assembly and the lower pump assembly are coaxially driven by the permanent magnet motor; an upper oil inlet is formed in the upper end of the upper pump assembly, an oil outlet of the upper pump assembly is connected with a mixing cavity of the lower pump assembly through an oil conveying pipe, a lower oil inlet is formed in the lower end of the mixing cavity of the lower pump assembly, an impeller cavity of the lower pump assembly is formed in the upper end of the mixing cavity of the lower pump assembly, and an oil outlet of the lower pump assembly is formed in the side face of the impeller cavity. The working performance of the lower pump is ensured, and the problem that the oil suction capacity of the upper pump is insufficient due to the length problem of the long-shaft centrifugal pump is solved. Meanwhile, in order to balance oil liquid hedging caused by simultaneous working of the upper pump and the lower pump, the sizes of impellers of the upper pump and the lower pump are adjusted, the upper impeller is reduced, and the lower impeller is enlarged to ensure that the capacity of the double pumps is not greatly influenced.

Description

Technical Field

[0001] The invention belongs to the field of centrifugal pump design, and relates to a double-suction centrifugal pump, and in particular to a structural design of a long-axis double-suction centrifugal pump for improving single-end oil supply capability. Background Art

[0002] Centrifugal pumps are conventional and mature pump structures, and double-end oil inlet centrifugal pumps have been designed in certain requirements, and therefore some technical solutions for double-end inlet centrifugal pumps have been generated. At present, in order to meet the needs of higher oil tanks, it is necessary to design a long-axis double-suction centrifugal pump. The centrifugal pump is long and has oil suction ports at both ends and an oil outlet at one end. Due to the length of the pump body, the oil suction capacity of one pump becomes weak when working alone, and due to the length of the pump, it also causes the problem of oil hedging when the two pumps are working. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a long-axis double-suction centrifugal pump, which solves the problem of insufficient oil suction capacity of the upper pump of the long-axis double-suction centrifugal pump and the offset of the working oil of the double pumps through a one-way valve structure and different designs of upper and lower pump impellers.

[0004] The technical solution of the present invention is as follows:

[0005] A long-axis double-suction centrifugal pump comprises an upper pump assembly, a lower pump assembly, an oil delivery pipe, a permanent magnet motor and a connecting pipe, wherein the upper pump assembly and the lower pump assembly are respectively arranged at the upper and lower ends of the permanent magnet motor and the connecting pipe, and the upper pump assembly and the lower pump assembly are coaxially driven by the permanent magnet motor; wherein the upper end of the upper pump assembly is an upper oil inlet, the oil outlet of the upper pump assembly is connected to the mixing chamber of the lower pump assembly through the oil delivery pipe, the lower end of the mixing chamber of the lower pump assembly is a lower oil inlet, the upper end of the mixing chamber of the lower pump assembly is the impeller chamber of the lower pump assembly, and the oil outlet of the lower pump assembly is arranged on the side of the impeller chamber.

[0006] Furthermore, a one-way valve is provided in the lower oil inlet, and the one-way valve has a direction from the outside of the lower pump assembly to the inside of the lower pump assembly.

[0007] Further, the one-way valve is closed when the upper pump works alone, and the one-way valve is opened when the lower pump works.

[0008] Furthermore, the lower end of the upper shell of the upper pump assembly is connected to the connecting pipe through a bolt structure, the motor shaft is wrapped inside the connecting pipe, and the lower end of the connecting pipe is connected to the permanent magnet motor through a bolt structure.

[0009] Furthermore, the lower end of the permanent magnet motor is connected to the lower pump casing of the lower pump assembly through a bolt structure, the motor shaft is wrapped in the lower pump casing, and the motor shaft wrapped by the lower pump casing passes through the lower impeller, the connecting rod and the inducer from top to bottom. The lower impeller is arranged in the impeller cavity of the lower pump assembly, the connecting rod is arranged in the mixing cavity, and the inducer is arranged in the oil inlet.

[0010] Furthermore, the upper oil inlet is provided with an upper oil inlet filter.

[0011] Furthermore, the lower oil inlet is provided with a lower oil inlet filter.

[0012] Furthermore, the ratio of the size of the upper impeller of the upper pump assembly to the size of the lower impeller of the lower pump assembly is 1:1.2 to 1:1.3.

[0013] Furthermore, the outlet of the oil delivery pipe connected to the mixing chamber is provided with an oblique upward deflection angle. The deflection angle is obliquely upward, forming a forward mixed flow with the oil entering the lower oil inlet introduced by the inducer, so as to better enter the lower pump assembly; and the fluid speed generated by the upper impeller will be faster than the fluid speed introduced by the inducer, forming an ejection principle, and improving the efficiency of the centrifugal pump.

[0014] The beneficial effects of the present invention are as follows:

[0015] 1. In the present invention, the one-way valve is closed when the upper pump is working, and is opened when the lower pump is working. A spring structure is provided at the valve and is fixed to the lower oil inlet by a retaining spring to ensure that the valve can be opened and closed at the appropriate time. When the valve is closed, the oil suction capacity of the upper pump is enhanced, and when the valve is opened, the lower pump works normally, thereby ensuring the working performance of the lower pump and avoiding the problem of insufficient oil suction capacity of the upper pump caused by the length problem of the long-axis centrifugal pump.

[0016] 2. At the same time, in order to balance the oil hedging caused by the simultaneous operation of the upper and lower pumps, the sizes of the upper and lower pump impellers are adjusted, the upper impeller is reduced and the lower impeller is enlarged to ensure that the dual pump capacity is not greatly affected. The patent of this invention is simple to operate and easy to install. Through the one-way valve structure and the difference design of the upper and lower pump impellers, it solves the problem of insufficient oil suction capacity of the upper pump of the long-axis double-suction centrifugal pump and the oil hedging of the dual pumps. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the structure of a long-axis double-suction centrifugal pump of the present invention;

[0019] Figure 2 is a cross-sectional view of a long-axis double-suction centrifugal pump of the present invention;

[0020] Among them, 1 is the oil pipeline, 2 is the upper pump housing, 3 is the connecting pipe, 4 is the permanent magnet motor, 5 is the lower pump housing, 6 is the lower oil inlet filter, 7 is the one-way valve, 8 is the lower oil inlet, 9 is the inducer, 10 is the connecting rod, 11 is the lower impeller, 12 is the motor plug, 13 is the graphite sealing ring, 14 is the upper impeller, 15 is the upper oil inlet filter, and 16 is the upper oil inlet. DETAILED DESCRIPTION

[0021] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the orientations or positional relationships in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or case referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be interpreted in a broad sense, for example, it can be a fixed connection, a detachable connection or an integrated connection; it can be a mechanical connection or a point connection; it can be a direct connection or 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 the present invention can be understood by specific circumstances.

[0024] Embodiment 1:

[0025] A long-axis double-suction centrifugal pump comprises an upper pump assembly, a lower pump assembly, an oil delivery pipe 1, a permanent magnet motor 4 and a connecting pipe 3, wherein the upper pump assembly and the lower pump assembly are respectively arranged at the upper and lower ends of the permanent magnet motor 4 and the connecting pipe 3, and the upper pump assembly and the lower pump assembly are coaxially driven by the permanent magnet motor 4; wherein the upper end of the upper pump assembly is an upper oil inlet 16, the oil outlet of the upper pump assembly is connected to the mixing chamber of the lower pump assembly through the oil delivery pipe 1, the lower end of the mixing chamber of the lower pump assembly is a lower oil inlet 8, the upper end of the mixing chamber of the lower pump assembly is the impeller chamber of the lower pump assembly, and the oil outlet of the lower pump assembly is arranged on the side of the impeller chamber.

[0026] A one-way valve 7 is provided in the lower oil inlet 8, and the one-way valve 7 has a one-way direction from the outside of the lower pump assembly to the inside of the lower pump assembly.

[0027] The one-way valve 7 is closed when the upper pump works alone, and is opened when the lower pump works.

[0028] The lower end of the upper shell 2 of the upper pump assembly is connected to the connecting pipe 3 through a bolt structure. The motor shaft is wrapped inside the connecting pipe 3, and the lower end of the connecting pipe 3 is connected to the permanent magnet motor 4 through a bolt structure.

[0029] The lower end of the permanent magnet motor 4 is connected to the lower pump housing 5 of the lower pump assembly through a bolt structure. The motor shaft is wrapped in the lower pump housing 5. The motor shaft wrapped by the lower pump housing 5 passes through the lower impeller 11, the connecting rod 10 and the inducer 9 from top to bottom. The lower impeller 11 is arranged in the impeller cavity of the lower pump assembly, the connecting rod 10 is arranged in the mixing cavity, and the inducer 9 is arranged in the oil inlet 8.

[0030] The upper oil inlet 16 is provided with an upper oil inlet filter 15 .

[0031] The lower oil inlet port 8 is provided with a lower oil inlet filter 6 .

[0032] The size ratio of the upper impeller 14 of the upper pump assembly to the size ratio of the lower impeller 11 of the lower pump assembly is 1:1.2 to 1:1.3.

[0033] The outlet direction of the oil delivery pipe 1 connected to the mixing chamber is provided with an oblique upward deflection angle. The deflection angle is obliquely upward, forming a forward mixed flow with the oil entering the lower oil inlet introduced by the inducer, so as to better enter the lower pump assembly; and the fluid speed generated by the upper impeller will be faster than the fluid speed introduced by the inducer, forming an ejection principle, and improving the efficiency of the centrifugal pump.

[0034] Embodiment 2:

[0035] The present invention designs a one-way valve structure at the lower pump. The one-way valve is closed when the upper pump is working, and is opened when the lower pump is working. A spring structure is provided at the valve and is fixed to the lower oil inlet by a retaining spring to ensure that the valve can be opened and closed at the appropriate time. When the valve is closed, the oil suction capacity of the upper pump is enhanced, and when it is opened, the lower pump works normally, which ensures the working performance of the lower pump and avoids the problem of insufficient oil suction capacity of the upper pump caused by the length problem of the long-axis centrifugal pump. At the same time, in order to balance the oil hedging caused by the simultaneous operation of the upper and lower pumps, the size of the upper and lower pump impellers is adjusted, the upper impeller is reduced, and the lower impeller is enlarged to ensure that the capacity of the dual pumps is not greatly affected. The patent of the present invention is simple to operate and easy to install. Through the one-way valve structure and the difference design of the upper and lower pump impellers, it solves the problem of insufficient oil suction capacity of the upper pump of the long-axis double-suction centrifugal pump and the hedging of the working oil of the dual pumps.

[0036] A long-axis double-suction centrifugal pump, the centrifugal pump includes an oil pipeline 1, the oil pipeline 1 is responsible for connecting an upper pump housing 2 and a lower pump housing 5, the upper housing 2 is provided with an oil inlet 16 and an oil outlet, the oil outlet is connected to the oil pipeline 1 through a sealing ring, the lower end of the upper housing 2 is connected to a connecting pipe 3 through a bolt structure, the motor shaft is wrapped inside the connecting pipe 3, and the lower end is connected to a permanent magnet motor 4 through a bolt structure, the lower end of the permanent magnet motor 4 is connected to the lower pump housing 5 through a bolt structure, and the lower pump housing 5 is provided with an oil inlet 8 and an oil outlet.

[0037] The lower shell 5 is connected to the permanent magnet motor 4 by bolts, and the permanent magnet motor shaft is wrapped in the lower shell. The motor shaft passes through the lower impeller 11, the connecting rod 10, and the inducer 9. A fastening structure is provided at the other end of the motor shaft. The lower shell 5 is connected to the lower oil inlet 8 and the lower oil inlet filter 6 by bolts. The lower oil inlet 8 is provided with a one-way valve 7 inside, which is fixed at the entrance by a slot and groove structure.

[0038] The upper shell 2 is connected to the permanent magnet motor 4 through the connecting pipe 3 using a bolt structure. The motor shaft of the permanent magnet motor 4 passes through the connecting pipe 3 and the upper shell 2. A graphite sealing ring 13 is used to ensure dynamic sealing between the connecting pipe 3 and the upper shell 2. Inside the upper shell 2, an upper impeller 14 is installed on the motor shaft and fixed on the shaft through a fastening structure. The upper oil inlet 16 is equipped with an upper oil inlet filter 15, and the upper oil inlet 16 is connected to the upper shell 2 through a bolt structure.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A long-axis double-suction centrifugal pump, characterized in that: The invention comprises an upper pump assembly, a lower pump assembly, an oil delivery pipe (1), a permanent magnet motor (4) and a connecting pipe (3), wherein the upper pump assembly and the lower pump assembly are respectively arranged at the upper and lower ends of the permanent magnet motor (4) and the connecting pipe (3), and the upper pump assembly and the lower pump assembly are coaxially driven by the permanent magnet motor (4); wherein the upper end of the upper pump assembly is an upper oil inlet (16), the oil outlet of the upper pump assembly is connected to the mixing chamber of the lower pump assembly through the oil delivery pipe (1), the lower end of the mixing chamber of the lower pump assembly is a lower oil inlet (8), the upper end of the mixing chamber of the lower pump assembly is an impeller chamber of the lower pump assembly, and the oil outlet of the lower pump assembly is arranged on the side of the impeller chamber.

2. A long-axis double-suction centrifugal pump according to claim 1, characterized in that: A one-way valve (7) is arranged inside the lower oil inlet (8), and the one-way valve (7) has a one-way direction from the outside of the lower pump assembly toward the inside of the lower pump assembly.

3. A long-axis double-suction centrifugal pump according to claim 2, characterized in that: The one-way valve (7) is closed when the upper pump works alone, and is opened when the lower pump works.

4. A long-axis double-suction centrifugal pump according to claim 1, characterized in that: The lower end of the upper shell (2) of the upper pump assembly is connected to the connecting pipe (3) via a bolt structure; the motor shaft is wrapped inside the connecting pipe (3) and the lower end of the connecting pipe (3) is connected to the permanent magnet motor (4) via a bolt structure.

5. A long-axis double-suction centrifugal pump according to claim 1, characterized in that: The lower end of the permanent magnet motor (4) is connected to the lower pump housing (5) of the lower pump assembly through a bolt structure. The motor shaft is wrapped in the lower pump housing (5). The motor shaft wrapped in the lower pump housing (5) passes through the lower impeller (11), the connecting rod (10) and the inducer (9) from top to bottom. The lower impeller (11) is arranged in the impeller cavity of the lower pump assembly, the connecting rod (10) is arranged in the mixing cavity, and the inducer (9) is arranged in the oil inlet (8).

6. A long-axis double-suction centrifugal pump according to claim 1, characterized in that: The upper oil inlet (16) of the upper pump assembly is equipped with an upper oil inlet filter (15).

7. A long-axis double-suction centrifugal pump according to claim 1, characterized in that: The lower oil inlet (8) of the lower pump assembly is equipped with a lower oil inlet filter (6).

8. A long-axis double-suction centrifugal pump according to claim 1, characterized in that: The ratio of the size of the upper impeller (14) of the upper pump assembly to the size of the lower impeller (11) of the lower pump assembly is 1:1.2 to 1:1.

3.

9. A long-axis double-suction centrifugal pump according to claim 1, characterized in that: The outlet of the oil delivery pipe (1) connected to the mixing chamber is arranged with an oblique upward deflection angle.

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