A low specific speed horizontal split high pressure double casing multistage pump

Abstract

The present application discloses a low specific speed horizontal split high pressure double-casing multistage pump, comprising: an outer casing having a pump cavity inside; an inner casing fixedly arranged on the inner wall of the outer casing, the volute flow channel in the inner casing adopts a single volute structure; an inlet arranged on the outer casing for introducing a medium; an outlet arranged on the outer casing for outputting the medium; a rotating shaft rotatably passing through the pump cavity; a driving side bearing assembly and a non-driving side bearing assembly arranged at both ends of the outer casing to respectively support the rotating shaft; a multistage impeller fixedly connected to the rotating shaft, the first-stage impeller in the multistage impeller corresponds to and is connected to the position of the inlet, and the last-stage impeller in the multistage impeller corresponds to and is connected to the position of the outlet. The low specific speed horizontal split high pressure double-casing multistage pump provided in this specification can adapt to the complex operating conditions of small flow and high head, and can operate smoothly and efficiently under small flow conditions.

Description

Technical Field

[0001] The present specification relates to the technical field of centrifugal pumps, and in particular to a low specific speed horizontal split high pressure double casing multistage pump. Background Art

[0002] The description in this section merely provides background information related to the disclosure of this specification and does not constitute prior art.

[0003] With the development of centrifugal pump application fields and the diversification of media, the operating conditions of centrifugal pumps are becoming more and more severe and complicated. When conventional multistage pumps operate under conditions that deviate from the design, their performance parameters will be greatly affected, especially when operating under low flow conditions, the efficiency of the device will be greatly reduced.

[0004] The common high-pressure multi-stage pumps on the market are designed for large flow and high head conditions, and it is difficult to ensure efficient operation under low flow conditions.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of this specification and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of this specification. Summary of the invention

[0006] In view of the deficiencies in the prior art, an object of this specification is to provide a low specific speed horizontal split high pressure double-casing multi-stage pump that can adapt to complex operating conditions of small flow and high head and can operate smoothly and efficiently under small flow conditions.

[0007] To achieve the above object, the embodiment of this specification provides a low specific speed horizontal split high pressure double casing multistage pump, comprising: An outer housing having a pump chamber therein; An inner casing is fixedly arranged on the inner wall of the outer casing, and the volute flow passage in the inner casing adopts a single volute structure; An inlet provided on the outer shell, for introducing a medium; An outlet provided on the outer shell, for outputting the medium; A rotating shaft rotatably passing through the pump chamber; The driving side bearing assembly and the non-driving side bearing assembly of the rotating shaft are respectively supported at two ends of the outer shell; A multi-stage impeller is fixedly connected to the rotating shaft, wherein a first-stage impeller in the multi-stage impeller corresponds to and is communicated with the position of the inlet, and a last-stage impeller in the multi-stage impeller corresponds to and is communicated with the position of the outlet.

[0008] As a preferred implementation, the inner casing adopts an axially split structure.

[0009] As a preferred implementation, the outer shell adopts a radially split structure.

[0010] As a preferred embodiment, the multi-stage impeller includes a first group of impellers and a second group of impellers arranged in the axial direction, and the orientation of the first group of impellers is opposite to that of the second group of impellers; the first group of impellers includes the first-stage impeller, and the second group of impellers includes the last-stage impeller.

[0011] As a preferred implementation, the first-stage impeller is located at an end of the first group of impellers away from the second group of impellers, and the last-stage impeller is located at an end of the second group of impellers close to the first group of impellers.

[0012] As a preferred implementation, in the axial direction, the inlet is close to the end of the outer shell, and the outlet is close to the middle of the outer shell.

[0013] As a preferred embodiment, the shapes of the volute flow passages of the odd-numbered stages are the same, and the shapes of the volute flow passages of the even-numbered stages are the same; and the shapes of the volute flow passages of the odd-numbered stages and the shapes of the volute flow passages of the even-numbered stages are symmetrically distributed.

[0014] As a preferred embodiment, the farthest distance from the volute flow passage to the rotation axis is smaller than the distance from the outer wall surface of the inner shell to the rotation axis.

[0015] As a preferred embodiment, the outlet width of the impeller is less than 5 mm.

[0016] As a preferred implementation, the rear cover plate of the impeller is connected by welding.

[0017] As a preferred implementation, the first-stage impeller is a double-suction impeller.

[0018] Beneficial effects:

[0019] The low specific speed horizontal split high pressure double casing multistage pump provided in this embodiment makes improvements in the design of the volute flow passage, designs the impeller and volute flow passage according to the low specific speed and small flow conditions, and changes the volute flow passage from a double volute to a single volute structure, which can adapt to the complex operating conditions of small flow and high head, and can operate stably and efficiently under small flow conditions. In addition, due to the use of a single volute structure, the flow passage area is increased, which can reduce the difficulty of casting.

[0020] In addition, the present application adopts a double shell structure (inner shell and outer shell), the flow channels are concentrated on the inner shell, and the outer shell completely wraps and covers the inner shell, which can enable the pump to withstand greater pressure and is suitable for high-lift application scenarios.

[0021] With reference to the following description and the accompanying drawings, the specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope thereby.

[0022] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0023] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 This is a schematic structural diagram of a low specific speed horizontal split high pressure double casing multistage pump provided in this embodiment; Figure 2 It is a schematic diagram of the structure of the odd-numbered volute flow passages and the even-numbered volute flow passages provided in this embodiment; Figure 3 This is a schematic structural diagram of an impeller provided in this embodiment that adopts a welding structure.

[0026] Description of reference numerals: 1. Outer casing; 2. Inner casing; 3. Volute flow channel; 4. Inlet; 5. Outlet; 6. Rotating shaft; 7. Impeller; 71. First-stage impeller; 72. Last-stage impeller; 8. Drive side bearing assembly; 9. Non-drive side bearing assembly; 10. Welding position. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0028] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0030] See also Figures 1 to 3 The embodiment of the present application provides a low specific speed horizontal split high pressure double casing multistage pump, comprising: an outer casing 1, an inner casing 2, an inlet 4, an outlet 5, a rotating shaft 6, a driving side bearing assembly 8, a non-driving side bearing assembly 9 and a multistage impeller 7.

[0031] Among them, the outer shell 1 has a pump cavity inside. The inner shell 2 is fixedly arranged on the inner wall of the outer shell 1. The volute flow channel 3 in the inner shell 2 adopts a single volute structure. The inlet 4 is arranged on the outer shell 1 for introducing the medium. The outlet 5 is arranged on the outer shell 1 for outputting the medium. The rotating shaft 6 rotatably passes through the pump cavity. The driving side bearing assembly 8 and the non-driving side bearing assembly 9 are arranged at both ends of the outer shell 1 to support the rotating shaft 6 respectively. One end of the rotating shaft 6 passes through the driving side bearing assembly 8 and is connected to the motor. The multi-stage impeller 7 is fixedly connected to the rotating shaft 6. The first-stage impeller 71 in the multi-stage impeller 7 corresponds to and is connected to the position of the inlet 4, and the last-stage impeller 72 in the multi-stage impeller 7 corresponds to and is connected to the position of the outlet 5.

[0032] The low specific speed horizontal split high pressure double casing multistage pump provided in this embodiment makes an improvement in the design of the volute flow passage 3, and designs the impeller 7 and the volute flow passage 3 according to the low specific speed and small flow conditions (when designing according to the low specific speed, the formula " ”), the volute flow channel 3 is changed from a double volute to a single volute structure, which can adapt to the complex operating conditions of small flow and high head, and can operate smoothly and efficiently under small flow conditions. And because of the single volute structure, the flow channel area is increased, which can reduce the difficulty of casting.

[0033] In addition, the present application adopts a double shell structure (inner shell 2 and outer shell 1), the flow channels are concentrated on the inner shell 2, and the outer shell 1 completely wraps and covers the inner shell 2, so that the pump can withstand greater pressure and is suitable for high-lift application scenarios.

[0034] Specifically, the farthest distance from the volute flow channel 3 to the rotating shaft 6 is smaller than the distance from the outer wall of the inner shell 2 to the rotating shaft 6, thereby ensuring that the volute flow channel 3 is concentrated in the inner shell 2 and does not extend out of the inner shell 2. The inner shell 2 is then completely wrapped and covered by the outer shell 1, so that the low specific speed medium-open high-pressure double-shell multi-stage pump can withstand greater pressure, thereby being suitable for application scenarios with high head and small flow.

[0035] In this embodiment, the low specific speed horizontal split high pressure double-shell multistage pump is installed horizontally in the centerline. The inner shell 2 is an axially split structure, and the outer shell 1 is a radially split structure. The inner shell 2 and the outer shell 1 cooperate to form a double shell structure.

[0036] like Figure 1 As shown, the multi-stage impeller 7 includes a first group of impellers and a second group of impellers arranged in the axial direction, the first group of impellers includes the first-stage impeller 71, and the second group of impellers includes the last-stage impeller 72. Figure 1 In the figure, the six impellers 7 on the left are the second group of impellers, and the six impellers 7 on the right are the first group of impellers. The first group of impellers are oriented in the opposite direction to the second group of impellers, that is, the impellers 7 are arranged back to back, which can balance the axial force of the pump device.

[0037] Specifically, the first-stage impeller 71 is located at one end of the first group of impellers away from the second group of impellers, and the final-stage impeller 72 is located at one end of the second group of impellers close to the first group of impellers. Accordingly, in the axial direction, the inlet 4 is arranged close to the end of the outer shell 1, and the outlet 5 is arranged close to the middle of the outer shell 1, which can make the overall structural layout of the pump device more reasonable and ensure that it has a strong pressure-bearing capacity.

[0038] In one embodiment, the first-stage impeller 71 is a double-suction impeller, which has better suction performance and can avoid gasification of high-pressure medium.

[0039] In this embodiment, the shapes of the volute flow passages 3 of the odd-numbered stages are the same, and the shapes of the volute flow passages 3 of the even-numbered stages are the same. Figure 2As shown, the left side is the odd-numbered volute flow channel 3, and the right side is the even-numbered volute flow channel 3. The shapes of the odd-numbered volute flow channels 3 and the even-numbered volute flow channels 3 are symmetrically distributed to adapt to the low-flow working conditions of the pump device. Such a design can not only ensure that the pump device operates efficiently under low-flow conditions, but also balance the radial force of the pump device to a certain extent.

[0040] Due to the small flow rate working condition, considering that the outlet width of the impeller 7 is small (the outlet width of the impeller 7 is less than 5mm), in order to ensure the efficient operation of the impeller 7, the rear cover of the impeller 7 is welded, and the welding position 10 is as follows Figure 3 Such a design can ensure the design accuracy of the outlet width of the impeller 7 and the smoothness of the flow channel inside the impeller 7, reduce the friction loss caused by the inside of the impeller 7, and improve the overall efficiency of the pump.

[0041] It should be noted that, in the description of this specification, the terms "first", "second", etc. are only used for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, and they cannot be understood as indicating or implying relative importance. In addition, in the description of this specification, unless otherwise specified, the meaning of "plurality" is two or more.

[0042] Any numerical value cited herein includes all values ​​of lower and upper values ​​that increase by one unit from the lower limit to the upper limit, and there is at least a two-unit interval between any lower value and any higher value. For example, if the value of the quantity of a component or a process variable (such as temperature, pressure, time, etc.) is set forth to be from 1 to 90, preferably from 20 to 80, and more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in the specification. For values ​​less than 1, one unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples that are intended to be clearly expressed, and it can be considered that all possible combinations of numerical values ​​listed between the lowest value and the highest value are clearly set forth in the specification in a similar manner.

[0043] Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. "About" or "approximately" used with a range applies to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", including at least the specified endpoints.

[0044] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for all purposes. The term "consisting essentially of..." to describe a combination should include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, parts or steps herein also contemplates embodiments that consist essentially of these elements, ingredients, parts or steps. By using the term "may", it is intended to indicate that any attribute described that "may" include is optional.

[0045] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0046] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents possessed by such claims. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of the subject matter, nor should it be considered that the inventors did not consider the subject matter to be part of the disclosed inventive subject matter.

Claims

1. A low specific speed horizontal split high pressure double casing multistage pump, characterized in that: include: An outer housing having a pump chamber therein; An inner casing is fixedly arranged on the inner wall of the outer casing, and the volute flow passage in the inner casing adopts a single volute structure; An inlet provided on the outer shell, for introducing a medium; An outlet provided on the outer shell, for outputting the medium; A rotating shaft rotatably passing through the pump chamber; The driving side bearing assembly and the non-driving side bearing assembly of the rotating shaft are respectively supported at two ends of the outer shell; A multi-stage impeller is fixedly connected to the rotating shaft, wherein a first-stage impeller in the multi-stage impeller corresponds to and is communicated with the position of the inlet, and a last-stage impeller in the multi-stage impeller corresponds to and is communicated with the position of the outlet.

2. The low specific speed horizontal split high pressure double casing multistage pump according to claim 1, characterized in that: The inner shell adopts an axially split structure.

3. The low specific speed horizontal split high pressure double casing multistage pump according to claim 1, characterized in that: The outer shell adopts a radially split structure.

4. The low specific speed horizontal split high pressure double casing multistage pump according to claim 1, characterized in that: The multi-stage impeller includes a first group of impellers and a second group of impellers arranged in the axial direction, and the orientations of the first group of impellers are opposite to those of the second group of impellers; the first group of impellers includes the first-stage impeller, and the second group of impellers includes the last-stage impeller.

5. The low specific speed horizontal split high pressure double casing multistage pump according to claim 4, characterized in that: The first-stage impeller is located at an end of the first group of impellers away from the second group of impellers, and the last-stage impeller is located at an end of the second group of impellers close to the first group of impellers.

6. The low specific speed horizontal split high pressure double casing multistage pump according to claim 1, characterized in that: In the axial direction, the inlet is close to the end of the outer shell, and the outlet is close to the middle of the outer shell.

7. The low specific speed horizontal split high pressure double casing multistage pump according to claim 1, characterized in that: The shapes of the volute flow passages of the odd-numbered stages are the same, and the shapes of the volute flow passages of the even-numbered stages are the same; the shapes of the volute flow passages of the odd-numbered stages and the shapes of the volute flow passages of the even-numbered stages are symmetrically distributed.

8. The low specific speed horizontal split high pressure double casing multistage pump according to claim 1, characterized in that: The farthest distance from the volute flow passage to the rotation axis is smaller than the distance from the outer wall surface of the inner shell to the rotation axis.

9. The low specific speed horizontal split high pressure double casing multistage pump according to claim 1, characterized in that: The outlet width of the impeller is less than 5 mm, and the rear cover plate of the impeller is connected by welding.

10. The low specific speed horizontal split high pressure double casing multistage pump according to claim 1, characterized in that: The first-stage impeller is a double-suction impeller.

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