Horizontal split multistage centrifugal pump transition flow channel and multistage centrifugal pump

Abstract

The application provides a horizontal middle-open multi-stage centrifugal pump transition flow channel and a multi-stage centrifugal pump. Two transition flow channels are symmetric along the center of a vortex chamber. The transition flow channel is used for connecting the vortex chamber and a circular cavity in which a next-stage impeller is installed. The transition flow channel comprises a diffusion section which is gradually expanded along the flow direction. The entrance and the exit of the diffusion section are at an acute angle with the horizontal center line, so as to reduce the radial length of the diffusion section. The included angle between the entrance and the exit of the diffusion section and the horizontal center line is not more than 30°. A guide plate is arranged in the transition flow channel at the front of the circular cavity, so as to divide the fluid entering the front of the circular cavity into two flows. The application changes the shape of the outer edge of the transition flow channel to improve the internal flow structure, reduces the hydraulic of the fluid, and achieves the purpose of further improving the head and efficiency of the low specific speed horizontal middle-open multi-stage centrifugal pump.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fluid machinery, in particular to a horizontal split multistage centrifugal pump transition flow channel and a multistage centrifugal pump. BACKGROUND

[0002] The transition flow channel is mainly applicable to the horizontal split multistage centrifugal pump, the pump volute is integrally cast, the rotor is supported at both ends, and the pump body is centrally supported, so that the stability is good, the reliability is high, and maintenance is convenient. The transition flow channel is a flow channel for liquid flow between stages, and the design of the transition flow channel not only determines the shape and castability of the pump body, but also has a certain influence on the efficiency of the pump.

[0003] The transition flow channel refers to a flow channel from the first stage volute throat to the inlet of the next stage impeller (adjacent or not adjacent), and its functions are:

[0004] 1. The first stage pressure chamber outlet is introduced to the inlet of the next stage impeller, and the liquid flow direction is turned by 180°;

[0005] 2. The velocity energy of the flow out of the volute is converted into pressure energy, and the hydraulic loss is reduced;

[0006] 3. The next stage impeller inlet is provided with uniform inflow.

[0007] At present, according to the different transition modes, the transition flow channels are generally divided into short transition flow channels and long transition flow channels. The existing transition flow channels have two forms of radial diffusion and oblique diffusion. The radial diffusion is that the transition flow channel has a diffusion section, which is located on the center line of the impeller, and diffuses to the diffusion section along the diffusion flow channel volute circle at a certain diffusion angle, and then turns into the next stage suction chamber. The oblique diffusion is that the diffusion flow channel does not diffuse along the volute circle, but obliquely penetrates through the pump body and directly turns into the next stage suction chamber. The radial diffusion transition flow channel has higher efficiency than the oblique diffusion flow channel, but the size is larger, and the pump body structure is not compact. While the oblique diffusion flow channel has a compact structure, but the hydraulic efficiency is reduced, and the pump cavitation is increased.

[0008] At present, the transition flow channels of domestic horizontal split multistage centrifugal pumps all adopt the mode of long transition flow channel combined with semi-spiral suction chamber, which not only makes the size of the pump body too large and the structure not compact, but also increases the pump cavitation allowance, increases the loss, and reduces the hydraulic efficiency. SUMMARY

[0009] In view of the deficiencies in the prior art, the application provides a horizontal split multi-stage centrifugal pump transition flow channel and a multi-stage centrifugal pump, which change the shape of the outer edge of the transition flow channel to improve the internal flow structure and reduce the fluid hydraulic, so as to further improve the head and efficiency of the low specific speed horizontal split multi-stage centrifugal pump; the horizontal split multi-stage centrifugal pump transition flow channel has the characteristics of simple structure, convenient processing and easy operation.

[0010] The application achieves the above technical purposes through the following technical means.

[0011] A horizontal split multi-stage centrifugal pump transition flow channel, two transition flow channels are symmetric along the center of the vortex chamber, the transition flow channel is used for connecting the vortex chamber and a circular cavity in which the next stage impeller is installed, the transition flow channel comprises a diffusion section, the diffusion section is gradually expanded along the flow direction, the inlet of the diffusion section and the position of the tongue are at an acute angle with the horizontal center line, and the radial length of the diffusion section is reduced.

[0012] Further, the included angle between the inlet of the diffusion section and the position of the tongue and the horizontal center line is not more than 30°.

[0013] Further, a guide plate is arranged in the transition flow channel at the front of the circular cavity, and the fluid entering the front of the circular cavity is divided into two streams.

[0014] Further, a recessed area is arranged on the outer edge of the transition flow channel opposite to the guide plate, so that the fluid entering the front of the circular cavity is divided into two streams with equal flow.

[0015] Further, at least one singular point is added to the outer edge profile of the transition flow channel, so that the outer edge of the transition flow channel presents a recessed area.

[0016] Further, a deswirler plate is arranged in the circular cavity, and the deswirler plate is located at the inlet of the transition flow channel into the circular cavity.

[0017] A horizontal split multi-stage centrifugal pump comprises the horizontal split multi-stage centrifugal pump transition flow channel.

[0018] The application has the following advantages:

[0019] 1. The horizontal split multi-stage centrifugal pump transition flow channel, the position of the tongue and the fluid inlet are at an acute angle of not more than 30° with the horizontal line, so as to reduce the radial length of the diffusion section; and a recessed area exists on the outer edge of the transition flow channel, which is flush with the center position of the guide plate, so as to reduce the influence of centrifugal force on the fluid, and the fluid can flow through the guide plate better, so that the fluid flow on the left and right sides of the guide plate is equal.

[0020] 2. The horizontal split multi-stage centrifugal pump transition flow channel, in the prior art, after the fluid flows through the diffuser section, due to the centrifugal force, the fluid will flow more to the right side of the guide plate, resulting in unequal fluid flow on both sides of the guide plate, uneven pressure distribution, causing a lot of hydraulic loss, therefore, the present application changes the outer edge of the transition flow channel, so that the outer edge profile has a singularity, causing the shell to partially recessed area, which can reduce the influence of centrifugal force on the fluid, so that the fluid flow on both sides of the guide plate is equal, and the pressure distribution is more uniform.

[0021] 3. The horizontal split multi-stage centrifugal pump transition flow channel has the characteristics of simple structure, easy processing and easy operation. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. The drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 It is a two-dimensional graph of the horizontal split multi-stage centrifugal pump transition flow channel.

[0024] Figure 2 It is a structural schematic diagram of the horizontal split multi-stage centrifugal pump transition flow channel.

[0025] Figure 3 It is a three-dimensional model diagram of the horizontal split multi-stage centrifugal pump transition flow channel.

[0026] Figure 4 It is a head comparison diagram of the horizontal split multi-stage centrifugal pump transition flow channel.

[0027] Figure 5 It is an efficiency comparison diagram of the horizontal split multi-stage centrifugal pump transition flow channel.

[0028] In the drawings:

[0029] 1-vortex chamber; 2-diffuser section; 3-guide plate; 4-anticlockwise plate; 5-tongue; 6-fluid inlet; 7-outer edge recess; 8-circular cavity. DETAILED DESCRIPTION

[0030] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals and characters throughout the figures denote the same or like components or elements having the same or similar functions. The embodiments described below are exemplary and intended to be illustrative of the present application and are not to be understood as limiting of the present application.

[0031] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are merely intended to facilitate the description of the present application and simplify the description, and thus cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and thus cannot be understood as limiting the present application. In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0032] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] As shown in Figure 1 and Figure 2 The horizontal split multi-stage centrifugal pump transition flow passage of the present application is shown in the drawings, wherein two of the transition flow passages are symmetrically arranged along the center of the vortex chamber 1, the transition flow passage is used to connect the vortex chamber 1 and the circular cavity 8 in which the next stage impeller is installed, the transition flow passage comprises a diffusion section 2, the diffusion section 2 is gradually expanded along the flow direction, the inlet of the diffusion section 2 and the position of the tongue 5 form an acute angle with the horizontal center line, which is used to reduce the radial length of the diffusion section, which is beneficial to reduce the hydraulic loss of the fluid in the diffusion section, and also makes the structure of the pump body compact. Generally, the included angle between the inlet of the diffusion section 2 and the position of the tongue 5 and the horizontal center line is not more than 30°, i.e. the included angle is in the range of 0~30°. As shown in Figure 1 , the embodiment is a model in which the inlet of the diffusion section 2 is deflected by 30° from the horizontal center line.

[0034] As shown in Figure 2 andFigure 3 As shown, the flow guide plate 3 is arranged in the transition flow channel in front of the circular cavity 8, for dividing the fluid before entering the circular cavity into two flows. There is a recessed area 7 on the outer edge of the transition flow channel, which is flush with the center of the flow guide plate 3, so as to reduce the influence of centrifugal force on the fluid, and enable the fluid to flow through the flow guide plate 3 better, so that the fluid flow on both sides of the flow guide plate 3 is equal.

[0035] In the embodiment, the recessed area 7 is at least one singular point added to the outer edge profile of the transition flow channel, so that the outer edge of the transition flow channel is recessed inward. Therefore, the recessed area 7 can be several singular points recessed inward added to the outer edge profile of the transition flow channel, or an arc or curve or intersecting line formed by continuous singular points recessed inward added to the outer edge profile of the transition flow channel. When the fluid flows through the diffuser section 2, due to the influence of centrifugal force, the fluid will deviate to the right side of the flow guide plate 3 and flow along the outer edge of the transition flow channel, which will cause uneven flow on both sides of the flow guide plate 3, uneven pressure distribution, and large vortex, resulting in large hydraulic loss. Therefore, by adding a singular point to the outer edge profile, a recessed area 7 is formed on the outer edge of the model, which can press the fluid to the other side of the flow guide plate 3, so that the fluid flow on both sides of the flow guide plate 3 is equal, the pressure distribution is more uniform, and the hydraulic loss is reduced.

[0036] The circular cavity 8 is provided with a deswirler 4, which is located at the entrance of the transition flow channel into the circular cavity. When the fluid flows into the circular cavity 8 from both sides, the deswirler 4 arranged therein can eliminate the motion circulation of the fluid and reduce the pre-whirl of the fluid, so that the fluid can flow into the next stage impeller inlet more uniformly.

[0037] Figure 4 The figure shows the head comparison diagram of the transition flow channel of the horizontal split multi-stage centrifugal pump, from which it can be seen that the present application not only ensures the head under the rated working condition, but also improves the head under the small flow working condition, thereby eliminating the hump phenomenon of the characteristic curve and improving the running stability of the horizontal split multi-stage centrifugal pump under the small flow working condition. Figure 5 The figure shows the efficiency comparison diagram of the transition flow channel of the horizontal split multi-stage centrifugal pump. From the figure, it can be seen that the efficiency of the present application under the rated working condition is improved by 3-4 percentage points, and the high efficiency zone is ensured to appear near the rated working condition.

[0038] A horizontal split multi-stage centrifugal pump comprising the horizontal split multi-stage centrifugal pump transition flow channel.

[0039] It should be understood that although the present specification is described in terms of various embodiments, each of which describes only one implementation, the specification is intended to cover all possible implementations that are within the scope of the application, which is defined by the claims. One skilled in the art will readily recognize from the disclosure herein, that alternative embodiments of the present application can be constructed from a number of approaches already known in the art, which do not depart from the spirit and scope of the present application. The individual features of the various embodiments of this application each will be recognized by one of ordinary skill in the art to be an innovative application that alone would entitle the applicant to a patent, but the present application is intended to cover each and every combination of the individual features disclosed herein and any other innovative feature that would be recognized by those of ordinary skill in the art to be an innovative application that alone would entitle the applicant to a patent. Therefore, the present application is not to be limited to only these explicitly disclosed embodiments.

[0040] The detailed description set forth above is merely illustrative of the application and is not intended to limit the scope of the application as defined by the claims. Rather, the scope of the application is to be determined solely by the claims.

Claims

1. A horizontal split multistage centrifugal pump transition channel, two of which are centrally symmetrical along the volute (1), said transition channel is used to connect the volute (1) with the circular cavity connected to the inlet of the next stage impeller, characterized in that, The transition runner includes a diffuser section (2) which is divergent in flow direction, the inlet of the diffuser section (2) and the position of the splitter (5) are at an acute angle with the horizontal center line, for reducing the radial length of the diffuser section; a guide vane (3) is arranged in the transition runner at the front of the circular cavity, for dividing the fluid entering the front of the circular cavity into two streams; a recess area (7) is arranged on the outer edge of the transition runner opposite the guide vane (3), by reducing the influence of centrifugal force on the fluid, so that the fluid entering the front of the circular cavity is divided into two streams with equal flow; by adding at least one singular point on the outer edge profile of the transition runner, the outer edge of the transition runner presents a recess area (7) which is concave inward.

2. The horizontal split multistage centrifugal pump transition channel of claim 1, wherein, The angle between the inlet of the diffuser section (2) and the position of the splitter (5) and the horizontal center line is not more than 30°.

3. The horizontal split multistage centrifugal pump transition channel of claim 1, wherein, A deswirler (4) is arranged in the circular cavity, and the deswirler (4) is located at the inlet of the transition runner into the circular cavity.

4. A horizontally split, multi-stage centrifugal pump, characterized in that, The horizontal split multi-stage centrifugal pump transition runner comprises the horizontal split multi-stage centrifugal pump transition runner according to any one of claims 1-3.

Images