WO2017088713A1

WO2017088713A1 - Multi-stage pump

Info

Publication number: WO2017088713A1
Application number: PCT/CN2016/106623
Authority: WO
Inventors: 张克凤; 乐吉娜; 张锡淼
Original assignee: 上海连成（集团）有限公司
Priority date: 2015-11-23
Filing date: 2016-11-21
Publication date: 2017-06-01
Also published as: CN106762675A

Abstract

A multi-stage pump comprises: a suction section (11), a discharge section (12), a middle section (13), a plurality of impellers (14), a plurality of guide vanes (15) and a pump shaft (16). An impeller (14) and a guide vane (15) together constitutes a pumping combination in an individual stage, so as to form multi-stage pumping combinations, and the multi-stage pumping combinations are mounted on the pump shaft (16) stage by stage. The pumping combinations can be detached from the pump shaft (16) and replaced by a matching replacement sleeve assembly, which includes an impeller replacement sleeve (21) and a diversion replacement sleeve (22). The impeller replacement sleeve (21) is mounted at the original axial mounting position of the replaced impeller, and a flow passage is formed between the diversion replacement sleeve (22) and the impeller replacement sleeve (21). A user can replace the pumping combinations of several stages of the multi-stage pump with replacement sleeve assembly (assemblies) according to actual working condition and head demand. Meanwhile, the diversion replacement sleeve can reduce the energy loss or volumetric loss originally caused by only applying the impeller replacement sleeve (s) in replacing, thereby increasing the energy efficiency.

Description

Multistage pump

Technical field

The invention relates to a pump, in particular to a multi-stage segment type multistage pump.

Background technique

A pump is a machine that delivers or pressurizes a liquid. The pump transfers the mechanical energy of the prime mover or other external energy to the liquid, increasing the energy of the liquid. According to the structure type, the pump can be divided into a single-stage pump and a multi-stage pump. Among them, the single-stage pump refers to a pump with only one-stage impeller, and the multi-stage pump refers to a pump with two or more stages of impellers. Multistage pumps typically include a suction section, a discharge section, a middle section, an impeller, a vane, and a pump shaft.

The user usually selects the appropriate pump based on the power or head required to actually use the pump. For a multi-stage pump, the rated power or head of the multistage pump is determined by the number of impeller stages it has. When the actual application conditions of the multi-stage pump change or apply to the situation where the working conditions change greatly, the user usually only adopts the following solutions: 1) For the new working condition, purchase a new one suitable for the new working condition. Multi-stage pump; 2) When the head of the multi-stage pump required for the new working condition is small, the first-stage or multi-stage impeller of the multi-stage pump and the corresponding vane are removed, and the impeller replacement sleeve is used instead and installed. The multi-stage pump either cuts the removed impeller and reinstalls it back into the multi-stage pump.

In the above solution, repurchasing a new multi-stage pump would incur additional costs, especially when the multi-stage pump was used less frequently, and the repurchase of the new multi-stage pump would be less cost effective. If an impeller replacement sleeve is used instead of the removed impeller, a cavity is formed between the adjacent two middle sections around the position of the impeller replacement sleeve mounted on the pump shaft, and the cavity will be formed when the multistage pump is operated. Part of the fluid is contained and adversely affects the flow of the fluid, resulting in power loss of the multi-stage pump, degrading the performance of the multi-stage pump. If the cutting impeller scheme is adopted, an irreversible structural change will be made to the impeller, so that the pump cannot be applied to a working condition requiring a large head again, unless a new impeller or a multistage pump is purchased, and resources (such as an impeller) cannot be realized. Reuse or recycling.

Summary of the invention

The technical problem to be solved by the present invention is to provide a multi-stage pump which, when replacing the pumping combination with the impeller replacement sleeve, increases the alternative method of the flow guiding replacement sleeve, so that the fluid can flow through the replacement sleeve assembly. Directly spouting through the fluid passage between the impeller replacement sleeve and the diversion replacement sleeve Pumping in the end direction without volume loss.

In order to solve the above technical problem, the present invention adopts the following technical solutions:

A multistage pump includes a suction section, a discharge section, a middle section, a plurality of impellers, a plurality of vanes, and a pump shaft through which fluid flows from the suction section to the discharge section, wherein the impeller And one of the vanes constitutes a primary pumping combination to form a multi-stage pumping combination, the multi-stage pumping combination being mounted stepwise on the pump shaft. The pumping assembly can be detached from the pump shaft and replaced with a mating replacement sleeve assembly that includes an impeller replacement sleeve and a flow control replacement sleeve, wherein the impeller replacement sleeve can be mounted to be replaced The original axial mounting position of the impeller, the flow guiding replacement sleeve is sealingly engaged with two adjacent middle sections, and a flow passage is formed between the flow guiding replacement sleeve and the impeller replacement sleeve.

In a preferred embodiment, the flow guiding replacement sleeve is an annular structure, the circulation passage is an annular passage, and the flow guiding replacement sleeve and the adjacent two of the middle portions constitute a closed annular cavity.

In a preferred embodiment, the radial distance between the impeller replacement sleeve and the flow guiding replacement sleeve is greater than or equal to the radial extent of the inlet of the impeller.

In a preferred embodiment, the other end of the flow guiding replacement sleeve is provided with a boss, and the boss is sealingly engaged with the middle portion.

In a preferred embodiment, one end of the flow guiding replacement sleeve is provided with a shoulder that is sealingly engaged with the middle section.

In a preferred embodiment, the multi-stage pump is a vertical multi-stage pump. In a preferred embodiment, the inner diameter of the flow guiding replacement sleeve is greater than or equal to the inner diameter of the middle portion.

In a preferred embodiment, the outer diameter of the impeller replacement sleeve is equal to the outer diameter of the hub of the impeller.

In a preferred embodiment, a seal is provided between the flow guiding replacement sleeve and the adjacent middle section.

Preferably, when the temperature of the fluid medium pumped by the multistage pump is <85 degrees Celsius, the seal is a barley paper pad.

Preferably, when the temperature of the fluid medium pumped by the multistage pump is ≥ 85 degrees Celsius, the seal is a ○-shaped rubber seal.

In a preferred embodiment, the pumping assembly further includes an impeller interstage sleeve between the two adjacent impellers. among them,

In a preferred embodiment, the axial length of the impeller replacement sleeve is equal to the axial length of the impeller.

In another preferred embodiment, the axial length of the impeller replacement sleeve is equal to the impeller level The sum of the axial length of the sleeve and the axial length of the impeller.

In still another preferred embodiment, the axial length of the impeller replacement sleeve is equal to the sum of the axial length of the interstage impeller sleeve of the two stages and the axial length of the impeller.

In a preferred embodiment, the impeller replacement sleeve rotates synchronously with the pump shaft, and the engagement between the flow guiding replacement sleeve and the adjacent middle portion is a static sealing fit.

The use of the invention has the following beneficial effects:

1. The multi-stage pump of the present invention uses a impeller replacement sleeve instead of a pumping combination in different working conditions or when it is required to change the multi-stage pump head. At the same time, a diversion replacement sleeve is used, and the fluid can be directly replaced by the impeller. The flow passage between the flow-replacement sleeves is pumped to the discharge end of the multi-stage pump, which improves the pumping efficiency and saves energy.

2. The multi-stage pump of the present invention seals the flow guiding replacement sleeve and the adjacent middle section together to form a closed annular cavity, so that fluid does not flow into the annular cavity, and the middle section of the stage is lowered. Obstruction of the fluid while reducing volume loss.

3. The multi-stage pump of the present invention is replaced by a replacement sleeve assembly, which does not require cutting of the impeller, and does not require the purchase of a new multi-stage pump according to new working conditions or head requirements, thereby saving costs. The replacement sleeve assembly can be reused, and the multi-stage pump can be adjusted in different lift ranges, which is conducive to saving resources and man-hours.

DRAWINGS

Figure 1 is a cross-sectional view showing a horizontal multistage pump of the first embodiment of the present invention at the time of shipment;

2 is a cross-sectional view of a multistage pump in which a primary pumping combination is substituted (not replacing the impeller interstage sleeve of the present stage) as an impeller replacement sleeve according to a first embodiment of the present invention;

Figure 3 is a cross-sectional view of a multi-stage pump in which a primary pumping combination is replaced with a replacement sleeve assembly in accordance with a first embodiment of the present invention;

Figure 4 is a cross-sectional view showing the replacement sleeve assembly of the first embodiment of the present invention;

Figure 5 is a cross-sectional view of a multi-stage pump employing another sealing method according to a first embodiment of the present invention;

Figure 6 is a cross-sectional view showing a vertical multi-stage pump of the second embodiment of the present invention;

Figure 7 is a cross-sectional view of a multi-stage pump in which a primary pumping combination is substituted (while replacing the upper stage impeller interstage) as a replacement sleeve assembly in accordance with a second embodiment of the present invention.

detailed description

The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiment shown in the drawings is not intended to limit the scope of the invention, but only to illustrate the spirit of the invention.

Referring to Figure 1, a multi-stage pump embodiment of the present invention includes a protective cover 10, a suction section 11, a discharge section 12, a plurality of intermediate sections 13, a plurality of impellers 14, a plurality of vanes 15, a pump shaft 16, and a plurality of The impeller stage sleeve 17 flows fluid from the suction section 11 through the middle section 13 to the discharge section 12. Among them, an impeller 14, a vane 15 and an impeller interstage sleeve 17 constitute a first-stage pumping combination, and the multi-stage pumping combination is mounted on the pump shaft 16 step by step.

The multi-stage pump is started, and the pump shaft 16 of the multi-stage pump is rotated by the external prime mover. At this time, the fluid in the impeller 14 is driven by the centrifugal force provided by the rotary motion of the impeller 14 along the multi-stage pumping combination. The stage is pumped from the suction section 11 to the discharge section 12. Among them, the fluid flowing through the multistage pump may be water, oil or the like.

According to the classification, the multi-stage pump can be divided into a horizontal multi-stage pump and a vertical multi-stage pump. The technical scheme adopted by the invention can be applied to a horizontal multi-stage pump or a vertical multi-stage pump. Preferred embodiments of the invention are as follows.

Embodiment 1

1 to 7 show a first embodiment of the present invention, in which the multistage pump shown is a horizontal multistage pump employing a horizontal segment structure. Fig. 1 is a schematic cross-sectional view showing the multistage pump of the first embodiment at the time of shipment, in which the pumping combinations of the stages of the multistage pump are not removed.

Figure 2 shows a schematic cross-sectional view of a multi-stage pump in which a primary pumping combination is replaced by an impeller replacement sleeve 21 (an impeller inter-stage sleeve 17 not substituted for this stage, optionally substituted), from the multi-stage pump At the movable end, the pumping combination of the stage is detached from the pump shaft 16 and replaced by a matching impeller replacement sleeve. After the replacement is performed, the alternative impeller replacement sleeve 21 is mounted to the original axial direction of the replaced impeller 14. Installation location. In the figure, the impeller replacement sleeve 21 and the adjacent lower stage impeller stage sleeve and the adjacent two intermediate sections form a cavity 31 through which the fluid flows during operation of the multistage pump. Since the radial dimension of the cavity 31 is large, when the fluid flows through the cavity 31, the middle section 13 has a certain hindrance to the fluid and is prone to fluid flow disturbance, thereby causing energy loss, and fluid output performance to the multistage pump. Have an adverse effect.

In a preferred embodiment, as shown in FIG. 3, this embodiment replaces the primary pumping assembly with a replacement sleeve assembly that includes an impeller replacement sleeve 21 and a flow control replacement sleeve 22. The replacement sleeve assembly employs a separate structure, i.e., the impeller replacement sleeve 21 and the flow control replacement sleeve 22 are separate, separate components. An annular flow passage 23 is formed between the flow control replacement sleeve 22 and the impeller replacement sleeve 21, and fluid can flow through the flow passage 23 to the next stage impeller 14.

After the replacement is implemented, the flow-replacement sleeve 22 is sealingly mated with the adjacent intermediate section 13 and forms a closed annular cavity 32 therebetween. The fluid flowing from the upper stage of the replacement sleeve assembly flows directly through the flow passage 23 to the next stage and does not enter the annular cavity 32, compared to the embodiment shown in Figure 2, the embodiment shown in Figure 3 There is substantially no loss of energy carried by the fluid in the flow through the flow passage 23. Thus, the use of the impeller replacement sleeve 21 and the flow control replacement sleeve 22 of the present invention in place of the pumping combination results in higher energy utilization than the prior art using only the impeller replacement sleeve 21 in place of the pumping assembly. Compared to the technical solution using only the impeller replacement sleeve 21, the multistage pump using the technical solution of the impeller replacement sleeve 21 and the flow guiding replacement sleeve 22 can increase the pumping efficiency by 2 to 3 percentage points.

In addition, in order to effectively exert the effect of the flow guiding replacement sleeve 22 to improve the pumping efficiency of the multistage pump, preferably, the radial distance between the impeller replacement sleeve 21 and the flow guiding replacement sleeve 22 may be set equal to or slightly larger than the impeller 14 The radial width of the inlet 141. Preferably, the outer diameter of the impeller replacement sleeve 21 is equal to the outer diameter of the hub 142 of the impeller 14. As shown in Figure 4, a radial cross-sectional view of a replacement sleeve assembly employing a separate configuration is shown in which an annular flow passage 23 is located between the impeller replacement sleeve 21 and the flow control replacement sleeve 22 and extends through the replacement sleeve assembly.

A static sealing fit is provided between the flow guiding replacement sleeve 22 and the middle section 13, and a seal can be provided between the flow guiding replacement sleeve 22 and the middle section 13. One end of the flow guiding replacement sleeve 22 is provided with a shoulder 221, and the shoulder 221 is sealingly engaged with the middle section 13. The other end of the flow guiding replacement sleeve 22 is provided with a boss 222. Similarly, the boss 222 is sealingly engaged with the middle section 13. A seal is provided between the shoulder 221 and the middle section 13 and between the boss 222 and the middle section 13.

Wherein, when the fluid temperature of the multi-stage pump is ≥85 degrees Celsius, the sealing member may be a ○-shaped rubber sealing ring 41, as shown in FIG. 3; when the fluid temperature of the multi-stage pump is <85 degrees Celsius, the sealing member may For the barley paper pad 42, the bark paper pad 42 is placed on the contact surface of the flow guiding replacement sleeve 22 and the middle section 13, as shown in FIG. It should be noted that the seal may take any suitable form as desired.

Here, the length of the impeller replacement sleeve can be set as needed. The axial length of the impeller replacement sleeve may be equal to the axial length of the impeller, in which case the impeller replacement sleeve merely replaces the impeller. Alternatively, the axial length of the impeller replacement sleeve is equal to the sum of the axial length of the impeller stage sleeve and the axial length of the impeller. At this time, the impeller replacement sleeve simultaneously replaces the impeller and the impeller stage sleeve. Alternatively, the axial length of the impeller replacement sleeve is equal to the sum of the axial length of the interstage impeller sleeve and the axial length of the impeller. Replace one impeller and two impeller stages.

Embodiment 2

6 and 7 show a second embodiment of the present invention, in which the multistage pump shown in the drawing is a vertical multistage pump adopting a vertical segment structure and is a bag type structure. Fig. 6 is a cross-sectional view showing the multistage pump of the second embodiment at the time of shipment from the factory, in which the pumping combinations of the stages of the multistage pump are not removed. Figure 7 shows a schematic cross-sectional view of a multi-stage pump in which a primary pumping combination is replaced by an impeller replacement sleeve 21 (alternatively replacing the upper impeller interstage jacket 17, optionally substituted), from the multi-stage pump At the end, the pumping combination of the stage is removed from the pump shaft 16 and replaced by a matching impeller replacement sleeve. After the replacement is performed, the alternative impeller replacement sleeve 21 is mounted to the original axial mounting position of the replaced impeller 14. .

In addition, in the present embodiment, the flow guiding replacement sleeve 22 is an annular structure and the shoulder and the boss of the first embodiment are not provided. Because the flow control replacement sleeve 22 is fixed when the multi-stage pump is in operation, and the impeller 14 rotates together with the pump shaft 16, in order to prevent friction loss between the flow guiding replacement sleeve 22 and the impeller 14, it is necessary to replace the diversion flow. The sleeve 22 is not in contact with the impeller 14. Preferably, the inner diameter of the flow guiding replacement sleeve 22 can be set equal to or slightly larger than the inner diameter of the middle section. Preferably, the outer diameter of the impeller replacement sleeve 21 is equal to the outer diameter of the hub 142 of the impeller 14.

In a variant, the flow-replacement sleeve 22 can also be provided with shoulders and bosses (not shown).

In each of the above embodiments, the primary replacement sleeve assembly may be selected to replace the primary pumping combination (as shown in FIG. 3), or the primary replacement sleeve assembly may be selected to replace the first-stage pumping combination and the upper-stage pumping combination of the impeller stage. The sleeve (Fig. 7), or the primary replacement sleeve assembly, may be selected to replace only the impeller and vanes of the primary pumping combination. The impeller replacement sleeve of the replacement sleeve assembly also has different axial lengths depending on the different alternatives of the primary replacement sleeve assembly. As shown in the embodiment of Figure 3, the axial length of the impeller replacement sleeve is equal to the axis of the impeller interstage sleeve. The sum of the length and the axial length of the impeller.

The present invention uses a replacement sleeve assembly instead of a pumping combination of a multi-stage pump, including but not limited to, it can be applied to a vertical and horizontal multi-stage pump, but any multi-stage pump adopting a multi-stage segment structure can be used. The technical solution described in the present invention is adopted.

In addition, the user can replace the one-stage or multi-stage pumping combination in the multi-stage pump with a replacement sleeve assembly according to the actual working conditions. The alternative pumping combination technology is determined by the multi-stage pump head required by the user. In the implementation of the replacement, it is necessary to start the disassembly from the driven end of the multi-stage pump, sequentially disassemble the pumping combination that needs to be replaced, and then install the replacement replacement sleeve assembly in turn, and finally package the multi-stage. The driven end of the pump. When the user needs to change the head of the multi-stage pump again, he only needs to change the alternative stage of the pumping combination to meet the user's demand for various working conditions.

The user can choose to use the ○-shaped rubber sealing ring, which can reduce the processing precision requirements of the metal contact surface between the flow guiding replacement sleeve and the middle section, thereby saving processing time. The sealing replaces the sealing fit between the sleeve and the middle section such that fluid does not enter the annular cavity 32, reducing energy loss or volume loss.

The preferred embodiments of the present invention have been described in detail hereinabove, and it is understood that various modifications and changes may be made by those skilled in the art. These equivalent forms are also within the scope defined by the claims appended hereto.

Claims

A multistage pump includes a suction section, a discharge section, a middle section, a plurality of impellers, a plurality of vanes, and a pump shaft through which fluid flows from the suction section to the discharge section, wherein the impeller Forming a multi-stage pumping combination with one of the vanes to form a multi-stage pumping combination, the multi-stage pumping combination being mounted step by step on the pump shaft, wherein the pumping combination is capable of Removing from the pump shaft and replacing it with a mating replacement sleeve assembly, the replacement sleeve assembly including an impeller replacement sleeve and a flow control replacement sleeve, wherein the impeller replacement sleeve can be mounted to the replaced impeller In the axial mounting position, the flow guiding replacement sleeve is sealingly engaged with two adjacent middle sections, and a flow passage is formed between the flow guiding replacement sleeve and the impeller replacement sleeve.
The multistage pump according to claim 1, wherein said flow guiding replacement sleeve is an annular structure, said circulation passage is an annular passage, and said flow guiding replacement sleeve and said adjacent two said intermediate portions are formed A closed annular cavity.
The multi-stage pump according to claim 1, wherein one end of the flow guiding replacement sleeve is provided with a boss, and the boss is sealingly engaged with the middle portion.
The multi-stage pump of claim 3 wherein the other end of the flow-replacement sleeve is provided with a shoulder that sealingly engages the mid-section.
The multi-stage pump according to claim 1, wherein a seal is provided between the flow guiding replacement sleeve and the adjacent middle portion.
The seal is a green paper pad or an O-ring.
The multi-stage pump of claim 1 wherein said pumping assembly further comprises an impeller interstage jacket, said interstage interstage of said impeller being located between adjacent ones of said impellers;

The axial length of the impeller replacement sleeve is equal to the axial length of the impeller; or

The axial length of the impeller replacement sleeve is equal to the sum of the axial length of the impeller interstage sleeve and the axial length of the impeller; or

The axial length of the impeller replacement sleeve is equal to the sum of the axial length of the interstage impeller sleeve of the two stages and the axial length of the impeller.
The multistage pump of claim 1 wherein said impeller replacement sleeve rotates synchronously with said pump shaft, and said engagement between said flow guiding replacement sleeve and said adjacent said intermediate section is a static sealing fit.
The multistage pump according to claim 1, wherein said flow guiding replacement sleeve The inner diameter is greater than or equal to the inner diameter of the middle section.
A multi-stage pump according to any one of claims 1-9, wherein the radial distance between the impeller replacement sleeve and the flow guiding replacement sleeve is greater than or equal to the radial extent of the inlet of the impeller.
A multi-stage pump according to any one of claims 1-9, wherein the outer diameter of the impeller replacement sleeve is equal to the outer diameter of the hub of the impeller.