WO2023142177A1 - 水泵进液结构 - Google Patents

水泵进液结构 Download PDF

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Publication number
WO2023142177A1
WO2023142177A1 PCT/CN2022/076325 CN2022076325W WO2023142177A1 WO 2023142177 A1 WO2023142177 A1 WO 2023142177A1 CN 2022076325 W CN2022076325 W CN 2022076325W WO 2023142177 A1 WO2023142177 A1 WO 2023142177A1
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liquid
inlet
pressure
liquid inlet
outlet
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PCT/CN2022/076325
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English (en)
French (fr)
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余梦琪
余敏
杨丹飞
周维坚
张丹艺
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浙江水泵总厂有限公司
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Publication of WO2023142177A1 publication Critical patent/WO2023142177A1/zh

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/426—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for liquid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/426—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for liquid pumps
    • F04D29/4293—Details of fluid inlet or outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
    • F04D29/669—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for liquid pumps

Definitions

  • the present application relates to the technical field related to water pumps, in particular to a liquid inlet structure of a water pump.
  • the length of the main shaft of the water pump will be increased after the induction wheel is installed, which will increase the processing difficulty of the main shaft and reduce the operation stability of the water pump; in addition, the design of the induction wheel often needs to be precisely adjusted according to the inlet pressure drop of the water pump and other values. Calculation and design are more difficult.
  • the application provides a water pump liquid inlet structure, including a pump base, a pump body and a connecting pipe, the pump body is located on the upper side of the pump base and fixed on the pump base; the pump body has a booster chamber, the The pump base is respectively provided with a liquid inlet and a liquid outlet, the liquid inlet is connected with the inlet of the pressurized chamber, and the liquid outlet is connected with the outlet of the pressurized chamber, so that the outside world enters the
  • the liquid in the liquid inlet can enter the pressurized chamber under the suction of the pressurized chamber, and flow out from the liquid outlet after being pressurized in the pressurized chamber; the communication pipe is fixed on the In the pump seat, the inlet of the communication pipe communicates with the liquid outlet, and the outlet of the communication pipe communicates with the liquid inlet, so that part of the liquid in the liquid outlet can flow into the liquid inlet. Under the action of the pressure difference between the liquid outlet and the liquid outlet, the flow returns to the liquid inlet through the communication pipe.
  • the liquid inlet structure of the above-mentioned water pump is fixed in the pump seat with connecting pipes connecting the liquid outlet and the liquid inlet respectively, so that part of the high-pressure liquid pressurized by the booster chamber will flow between the liquid outlet and the liquid inlet. Under the action of the pressure difference, it flows into the liquid inlet through the connecting pipe, and mixes with the high-temperature liquid to be transported in the liquid inlet to increase the absolute pressure of the mixed liquid, and then increase the absolute pressure of the liquid when it enters the booster chamber, so as to reduce or even avoid The effect of liquid cavitation.
  • the pressure P 1 of the liquid flowing into the liquid inlet from the outside, the pressure drop NPSHr at the pump inlet, and the vaporization pressure P of the liquid being delivered are all fixed external environmental parameters, so the flow into the liquid inlet through the connecting pipe is increased. If the liquid pressure P 2 satisfies the above formula, it can ensure that the liquid flowing into the booster chamber will not have cavitation, so as to achieve the effect of improving the cavitation performance of the water pump.
  • the pressure P 2 of the liquid flowing into the liquid inlet through the communication pipe is greater than 0.72Mpa.
  • the diameter of the inner wall of the connecting pipe is 3mm-5mm.
  • the pressure P2 of the liquid flowing into the liquid inlet through the connecting pipe can be guaranteed to be greater than 0.72Mpa.
  • the pump base further has a mixing chamber, the inlet of the mixing chamber communicates with the liquid inlet, and the outlet of the mixing chamber communicates with the pressurizing chamber.
  • the low-pressure liquid directly input from the outside and the high-pressure liquid returned by the connecting pipe can be fully mixed in the mixing chamber, so as to avoid the two-stage differentiation of the high-low pressure liquid due to insufficient mixing, thereby destroying the flow state of the liquid.
  • the central axis of the mixing chamber is collinear with the central axis of the pressurization chamber; one end of the communication pipe is located at the inlet of the mixing chamber, and is co-linear with the central axis of the mixing chamber. Wire.
  • the inlet diameter of the mixing chamber is smaller than the outlet diameter.
  • the low-pressure liquid and the high-pressure liquid meet at the entrance of the mixing chamber.
  • the low-pressure and high-pressure liquids can be fully contacted and mixed, increasing the mixing effect, avoiding the polarization of high and low pressure, and destroying the liquid. fluid state.
  • the pump seat further includes a flow guide part, and the surface of the flow guide part away from the liquid outlet is inclined from top to bottom in a direction close to the central axis of the pressurization chamber, and The side surface cooperates with the inner wall of the pump seat to form a diversion cavity; the other side surface of the guide part close to the liquid outlet cooperates with the inner wall of the pump seat to form the mixing chamber; the guide part Smooth transitions between surfaces on both sides.
  • the flow direction of the low-pressure liquid input from the outside is the same as the high-pressure liquid returned by the connecting pipe, so as to avoid turbulent flow or energy loss caused by the high-low pressure liquid colliding with each other.
  • the inlets of the communication pipes and the liquid outlets are arranged alternately.
  • the staggered arrangement can reduce the interference caused by the diversion output of the connecting pipe to the liquid output of the liquid outlet, thereby effectively reducing the drop in pressure of the liquid output from the liquid outlet, thereby satisfying the demand for high-temperature liquid delivery. At the same time, avoid a significant reduction in the head of the water pump.
  • the inlet of the communication pipe is located at the lower side of the liquid outlet; the communication pipe is inclined from the inlet to the side away from the pump body, and the angle between the connection pipe and the horizontal plane is 8° °.
  • part of the high-pressure liquid flowing from the pressurization chamber to the liquid outlet can flow into the connecting pipe relatively smoothly and be returned to the liquid inlet, thereby avoiding the collision between the returned high-pressure liquid and the inner wall of the pump seat, reducing the Energy loss in high pressure liquids.
  • Fig. 1 is the sectional structure schematic diagram of the present application
  • Fig. 2 is a schematic diagram of the liquid flow in Fig. 1 .
  • first and second are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features.
  • the features defined as “first” and “second” may explicitly or implicitly include at least one of these features.
  • “plurality” means at least two, such as two, three, etc., unless otherwise specifically defined.
  • a first feature is “on” or “under” a second feature, which means that the first feature is directly in contact with the second feature, or that the first feature and the second feature are indirectly in contact with each other. contact through an intermediary.
  • “above”, “above” and “above” the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or it just means that the first feature is higher in level than the second feature.
  • “Below”, “beneath” and “under” the first feature may mean that the first feature is directly below or obliquely below the second feature, or it just means that the level of the first feature is smaller than that of the second feature.
  • the centrifugal pump When the centrifugal pump is working, the absolute pressure of the liquid at the inlet of the impeller will drop due to a certain vacuum pressure. When the absolute pressure of the liquid after the pressure drop is lower than the vaporization pressure P of the liquid at this temperature, the liquid enters the centrifugal pump. When the absolute pressure P a of the first stage impeller of the pump - the pump inlet pressure drop NPSHr ⁇ the vaporization pressure P of the liquid, the liquid will undergo cavitation, which will affect the normal operation of the pump or even damage the pump;
  • Reducing the pressure drop NPSHr at the pump inlet can be achieved by improving the design of the flow channel and impeller, which can be generally applied to various types of centrifugal pumps, but the effect on improving the cavitation performance of centrifugal pumps is relatively small.
  • the vaporization pressure of the liquid will be greatly increased, and the reduction of the pump inlet pressure drop NPSHr brought about by improving the flow channel is not enough to offset the increase in the vaporization pressure P of the liquid, and cavitation will still occur;
  • the method of adding an inducer before the first-stage impeller is mostly adopted to increase the absolute pressure P a of the liquid when it enters the first-stage impeller, but the installation of the inducer will increase the length of the main shaft of the pump, thereby As a result, the processing difficulty of the main shaft increases, and at the same time, the operation stability of the water pump decreases;
  • the design of the inducer often needs to be precisely calculated according to the inlet pressure drop NPSHr of the pump and other values. For example, if the effective NPSH added by the inducer is too small, the effect of avoiding cavitation cannot be achieved; If the increased effective NPSH is too large, the inducer will be too large, resulting in excessive processing costs and low pump operation stability.
  • the water pump liquid inlet structure includes a pump base 10, a pump body 20 and a connecting pipe 30, the pump body 20 is located on the upper side of the pump base 10 and Fixed on the pump base 10; the pump body 20 has a pressurized chamber 21, the pump base 10 is respectively provided with a liquid inlet 11 and a liquid outlet 12, the liquid inlet 11 communicates with the inlet of the pressurized chamber 21, and the liquid outlet 12 It communicates with the outlet of the pressurization chamber 21, so that the liquid entering the liquid inlet 11 from the outside can enter the pressurization chamber 21 under the suction of the pressurization chamber 21, and after being pressurized in the pressurization chamber 21, it will be released from the liquid outlet.
  • the communication pipe 30 is fixed in the pump base 10, the inlet of the communication pipe 30 communicates with the liquid outlet 12, and the outlet of the communication pipe 30 communicates with the liquid inlet 11, so that part of the liquid in the liquid outlet 12 can be The pressure difference between the liquid inlet 11 and the liquid outlet 12 flows back to the liquid inlet 11 through the communication pipe 30 .
  • the pressurization chamber 21 is provided with pressurization components such as impellers, which can pressurize the liquid flowing into the pressurization chamber 21, so the absolute pressure when the liquid enters the pressurization chamber 21 is the absolute pressure P when the liquid enters the first-stage impeller a ;
  • pressurization components such as impellers, which can pressurize the liquid flowing into the pressurization chamber 21, so the absolute pressure when the liquid enters the pressurization chamber 21 is the absolute pressure P when the liquid enters the first-stage impeller a ;
  • the high-temperature liquid to be transported enters the pump base 10 through the liquid inlet 11, and enters the pressurized chamber 21 in the pump body 20 through the pump base 10, and is output from the liquid outlet 12 after being pressurized by the pressurized chamber 21, and partly increased
  • the compressed high-pressure liquid flows into the liquid inlet 11 through the connecting pipe 30 under the action of the pressure difference between the liquid outlet 12 and the liquid inlet 11, and mixes with the high-temperature liquid to be transported in the liquid inlet 11, so as to improve the temperature of the mixed liquid.
  • the absolute pressure and then increase the absolute pressure Pa when the liquid enters the pressurization chamber 21, thereby reducing or even avoiding the possibility of cavitation caused by the pressure drop after the liquid enters the pressurization chamber 21.
  • the pressure drop NPSHr at the pump inlet depends on the structure of the booster components in the booster chamber 21, such as the flow path structure of the first stage impeller, which is an external environmental parameter;
  • the pressure P1 of the liquid flowing into the liquid inlet 11 from the outside is also External environmental parameters;
  • the vaporization pressure P of the liquid depends on the temperature and type of the liquid, which is also an external environmental parameter;
  • the pressure P 2 of the liquid flowing into the liquid inlet 11 through the communication pipe 30 can only be increased.
  • the conveyed liquid is high temperature and high pressure water of 180 degrees, its vaporization pressure P is 1Mpa, and the liquid pressure P1 when flowing into the liquid inlet 11 from the outside is 0.3Mpa
  • the water pump in the embodiment shown in Fig. 1 the flow rate of its pump inlet is usually 0.7m/s ⁇ 0.9m/s, so the pressure drop NPSHr of pump inlet is about 2m, namely 0.02Mpa;
  • the pressure P of the liquid flowing into the liquid inlet 11 through the communication pipe 30 needs to be greater than 0.72Mpa, so as to ensure that the absolute pressure Pa of the mixed liquid after passing through the pressure drop of the booster chamber 21 is still greater than its vaporization pressure P , thus achieving the effect of avoiding cavitation.
  • the absolute pressure Pa of the liquid usually reserves at least 0.5m, that is, a safety margin of 0.005Mpa. Therefore, the pressure P of the liquid flowing into the liquid inlet 11 through the communication pipe 30 needs to be Greater than 0.725Mpa.
  • liquid pressure P2 flowing into the liquid inlet 11 through the connecting pipe 30 is affected by the flow rate at the liquid outlet 12, the pressure at the liquid outlet 12, and the caliber of the connecting pipe 30 and other factors;
  • the liquid pressure P2 flowing into the liquid inlet 11 through the communication pipe 30 is 0.72Mpa, it is calculated in conjunction with factors such as the flow value and the pressure value at the water pump liquid outlet 12 in the embodiment shown in Figure 1
  • the diameter of the inner tube wall of the communication pipe 30 is 3 mm to 5 mm; under the caliber of the communication pipe 30, the pressure P2 of the liquid flowing into the liquid inlet 11 through the communication pipe 30 can be guaranteed to be greater than 0.72 Mpa.
  • the diameter of the inner tube wall of the communication pipe 30 is 3mm, so that while the pressure P2 of the liquid flowing into the liquid inlet 11 through the communication pipe 30 is greater than 0.72Mpa, the high pressure returned to the liquid inlet 11 can be relatively reduced Liquid, so that most of the high-pressure liquid can be output from the liquid outlet 12, and then the effect of improving the liquid outlet efficiency of the water pump can be achieved.
  • the required pressure remains constant at 0.72Mpa
  • the diameter of the connecting pipe 30 needs to be increased accordingly; and when the pressure at the liquid outlet 12 increases , when the flow rate is constant, the required diameter of the connecting pipe 30 can be reduced accordingly.
  • the pump base 10 also has a mixing chamber 13, the inlet of the mixing chamber 13 communicates with the liquid inlet 11, and the outlet of the mixing chamber 13 communicates with the booster chamber 21; the low-pressure liquid directly input from the outside
  • the high-pressure liquid returned by the connecting pipe 30 can be fully mixed in the mixing chamber 13 to avoid two-stage differentiation of the high-pressure and low-pressure liquid due to insufficient mixing, that is, two regions of high pressure and low pressure appear, thereby destroying the flow state of the liquid.
  • the central axis of the mixing chamber 13 is collinear with the central axis of the pressurization chamber 21; one end of the communication pipe 30 is located at the inlet of the mixing chamber 13, and is collinear with the central axis of the mixing chamber 13;
  • the inlet and outlet of the mixing chamber 13 the inlet of the pressurization chamber 21 and the outlet of the connecting pipe 30 all collinear, thereby ensuring that the low-pressure liquid input from the outside through the liquid inlet 11 is transferred from the connecting pipe
  • the flow direction of the high-pressure liquid returned by 30 and the mixed liquid output by the pressurization chamber 21 after mixing are the same; on the one hand, avoid the turbulent flow caused by the collision of the input low-pressure and high-pressure liquids; Collision of the inner walls of the seat 10 results in energy loss.
  • the inlet diameter of the mixing chamber 13 is smaller than the outlet diameter; because the low-pressure liquid input from the outside enters the mixing chamber through the inlet of the mixing chamber 13, and one end of the connecting pipe 30 is positioned at the inlet of the mixing chamber 13, that is The low-pressure liquid and the high-pressure liquid meet at the entrance of the mixing chamber 13. Therefore, by reducing the entrance of the mixing chamber 13, compared with the entrance with a larger diameter, the low-pressure and high-pressure liquids can be fully contacted and mixed to increase the mixing effect and avoid high pressure. The low pressure polarizes, disrupting the flow regime of the liquid.
  • the inlet diameter of the mixing chamber 13 is 16 mm, and the outlet diameter is the same as the inlet diameter of the first-stage impeller in the booster chamber 21 , both of which are 37 mm.
  • the pump base 10 further includes a guide part 15 , the surface of the guide part 15 away from the liquid outlet 12 is inclined from top to bottom in a direction close to the central axis of the pressurization chamber 21 , and The side surface cooperates with the inner wall of the pump seat 10 to form a diversion cavity 16; the other side surface of the diversion part 15 near the liquid outlet 12 cooperates with the inner wall of the pump seat 10 to form a mixing chamber 13; between the two side surfaces of the diversion part 15 Smooth transition.
  • the liquid inlet 11 includes a diversion chamber 16 and a mixing chamber 13, and one end of the diversion chamber 16 communicates with the inlet of the mixing chamber 13; Flow cavity 16 flows smoothly to avoid energy loss caused by liquid colliding with the inner wall of pump base 10;
  • outlet direction of the diversion cavity 16 is consistent with the outlet direction of the communication pipe 30, so that the flow direction of the low-pressure liquid input from the outside and the high-pressure liquid returned by the communication pipe 30 are the same, thereby avoiding turbulence caused by the collision between the high and low pressure liquids. flow or cause energy loss.
  • the inlet of the communication pipe 30 and the liquid outlet 12 are staggered; the staggered arrangement here means that the projections of the inlet of the communication pipe 30 and the liquid outlet 12 on the vertical plane at the center of the two do not intersect.
  • the interference caused by the split output of the connecting pipe 30 to the liquid output of the liquid outlet 12 can be reduced, thereby effectively reducing the pressure of the liquid output from the liquid outlet 12. Reduce the amount, so as to meet the high-temperature liquid delivery requirements while avoiding a significant reduction in the pump head.
  • the inlet of the communication pipe 30 is located at the lower side of the liquid outlet 12; the communication pipe 30 is inclined from the inlet to the side away from the pump body 20, and the angle between it and the horizontal plane is 8° set in this way, so that part of the high-pressure liquid flowing from the booster chamber 21 to the liquid outlet 12 can flow into the connecting pipe 30 smoothly and return to the liquid inlet 11, thereby avoiding the return of the high-pressure liquid and the pump seat 10 Collision occurs on the inner wall of the high-pressure liquid to reduce the energy loss of the high-pressure liquid.
  • a plurality of casting holes 14 are provided on the surface of the pump base 10 to make the wall thickness of the pump base 10 uniform, thereby reducing the casting cost of the pump base 10 while meeting the casting requirements.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

本申请涉及一种水泵进液结构，包括泵座(10)、泵体(20)以及连通管(30)，泵体(20)位于泵座(10)上侧且固设于泵座(10)；泵体(20)内具有增压腔(21)，泵座(10)分别开设有进液口(11)与出液口(12)，进液口(11)与增压腔(21)的入口连通，出液口(120)与增压腔(21)的出口连通；连通管(30)固设于泵座(10)内，连通管(30)的入口与出液口(12)连通，连通管(30)的出口与进液口(11)连通。

Description

水泵进液结构
相关申请
本申请要求2022年1月28日申请的，申请号为202210109159.1，发明名称为“水泵进液结构”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及水泵相关技术领域，特别是涉及一种水泵进液结构。
背景技术
为充分利用锅炉产能过程中输出的高温高压水，通常需要水泵进行高温水的输送。
由于液体的温度越高，其自身的汽化压力越高，且当输送液体的绝对压力小于其自身在该温度的汽化压力时，输送液体会汽化并发生汽蚀，因此高温液体极易在输送过程中发生汽蚀并导致水泵损坏；
目前的水泵在输送高温水时，大多采取在首级叶轮之前加装诱导轮的方式以减小水泵的必需汽蚀余量，即增加液体的绝对压力，从而避免输送的高温水发生汽蚀；
但加装诱导轮后会增加水泵主轴的长度，从而导致主轴的加工难度上升，同时会导致水泵的运行稳定性下降；此外，诱导轮在设计时往往需要根据水泵的进口压力降等数值进行精密计算，设计难度较大。
发明内容
基于此，有必要针对通过加设诱导轮增加水泵汽蚀性能的方式，设计难度大，且会导致主轴加工难度上升，水泵运行稳定性下降的问题，提供一种设计、加工简单，运行稳定且能够增加水泵汽蚀性能的水泵进液结构。
本申请提供一种水泵进液结构，包括泵座、泵体以及连通管，所述泵体位于所述泵座上侧且固设于所述泵座；所述泵体内具有增压腔，所述泵座分别开设有进液口与出液口，所述进液口与所述增压腔的入口连通，所述出液口与所述增压腔的出口连通，以使得由外界进入所述进液口的液体能够在所述增压腔的吸力作用下进入所述增压腔，并在所述增压腔内增压后由所述出液口流出；所述连通管固设于所述泵座内，所述连通管的入口与所述出液口连通，所述连通管的出口与所述进液口连通，以使得所述出液口内的部分液体能够 在所述进液口与所述出液口之间的压差作用下通过所述连通管回流至所述进液口。
上述水泵进液结构，通过在泵座内固设分别连通出液口以及进液口的连通管，以使得部分由增压腔增压后的高压液体会在出液口与进液口之间的压差作用下通过连通管流入进液口，并与进液口中的待输送高温液体混合，以提高混合后液体的绝对压力，进而提高液体进入增压腔时的绝对压力，达到减少甚至避免液体发生汽蚀的效果。
在其中一个实施例中，由外界流入所述进液口的液体压力P 1+通过所述连通管流入所述进液口的液体压力P 2-泵进口的压力降NPSHr＞所输送液体的汽化压力P。
可以理解的是，由外界流入所述进液口的液体压力P 1、泵进口的压力降NPSHr以及所输送液体的汽化压力P均为固定的外部环境参数，因此提高通过连通管流入进液口的液体压力P 2至满足上述公式，即可保证流入增压腔内的液体不会发生汽蚀，从而达到提高水泵汽蚀性能的效果。
在其中一个实施例中，通过所述连通管流入所述进液口的液体压力P 2大于0.72Mpa。
在其中一个实施例中，所述连通管的内管壁直径为3mm～5mm。
可以理解的是，结合水泵出液口处的流量数值及压力数值等因素进行计算后，在此连通管口径下，能够保证通过连通管流入进液口的液体压力P 2大于0.72Mpa。
在其中一个实施例中，所述泵座还具有混合腔，所述混合腔的入口与所述进液口连通，所述混合腔的出口与所述增压腔连通。
可以理解的是，由外界直接输入的低压液体与由连通管回输的高压液体能够在混合腔进行充分混合，以避免高低压液体因混合不足导致出现两级分化，从而破坏液体的流态。
在其中一个实施例中，所述混合腔的中轴线与所述增压腔的中轴线共线；所述连通管的一端位于所述混合腔的入口，且与所述混合腔的中轴线共线。
可以理解的是，通过进液口由外界输入的低压液体、由连通管回输的高压液体以及混合后经增压腔输出的混合液体，三者的流向相同；一方面避免输入的低压与高压液体相互碰撞导致紊流，另一方面避免上述三种液体与泵座的内壁碰撞导致能量损耗。
在其中一个实施例中，所述混合腔的入口直径小于出口直径。
可以理解的是，低压液体与高压液体于混合腔的入口处汇合，通过减小混合腔的入口，能够使得低压与高压液体充分接触并混合，增加混合效果，避免高低压两极分化，破坏液体的流态。
在其中一个实施例中，所述泵座还包括导流部，所述导流部远离所述出液口一侧的表面自上往下向靠近所述增压腔中轴线的方向倾斜，且该侧表面配合所述泵座的内壁形成导流腔；所述导流部靠近所述出液口的另一侧表面配合所述泵座的内壁形成所述混合腔；所 述导流部的两侧表面之间平滑过渡。
可以理解的是，由外界输入的低压液体与由连通管回输的高压液体的流向相同，从而避免高低压液体因相互碰撞导致紊流或导致能量损失。
在其中一个实施例中，所述连通管的入口与所述出液口交错设置。
可以理解的是，交错设置能够减少因连通管的分流输出对出液口的液体输出所造成的干扰，从而有效减小出液口输出液体的压力的降低量，从而在满足高温液体输送需求的同时，避免水泵扬程大幅降低。
在其中一个实施例中，所述连通管的入口位于所述出液口下侧；所述连通管自入口处向远离所述泵体的一侧倾斜，且与水平面之间的夹角为8°。
可以理解的是，由增压腔流至出液口的部分高压液体，能够较为平滑地流入连通管并回输至进液口，从而避免回输的高压液体与泵座的内壁发生碰撞，减少高压液体的能量损失。
附图说明
为了更清楚地说明本申请实施例或传统技术中的技术方案，下面将对实施例或传统技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅是本申请的一些实施例，对于本领域普通技术人员而言，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本申请的剖视结构示意图；
图2为图1中的液体流向示意图。
附图标记：10、泵座；11、进液口；12、出液口；13、混合腔；14、铸造孔；15、导流部；16、导流腔；20、泵体；21、增压腔；30、连通管。
具体实施方式
为使本申请的上述目的、特征和优点能够更加明显易懂，下面结合附图对本申请的具体实施方式做详细的说明。在下面的描述中阐述了很多具体细节以便于充分理解本申请。但是本申请能够以很多不同于在此描述的其它方式来实施，本领域技术人员可以在不违背本申请内涵的情况下做类似改进，因此本申请不受下面公开的具体实施例的限制。
需要说明的是，当组件被称为“固定于”或“设置于”另一个组件，它可以直接在另一个组件上或者也可以存在居中的组件。当一个组件被认为是“连接”另一个组件，它可以是直接连接到另一个组件或者可能同时存在居中组件。本申请的说明书所使用的术语 “垂直的”、“水平的”、“上”、“下”、“左”、“右”以及类似的表述只是为了说明的目的，并不表示是唯一的实施方式。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在本申请的描述中，“多个”的含义是至少两个，例如两个，三个等，除非另有明确具体的限定。
在本申请中，除非另有明确的规定和限定，第一特征在第二特征“上”、“下”可以是第一特征直接和第二特征接触，或第一特征和第二特征间接地通过中间媒介接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅表示第一特征水平高度小于第二特征。
除非另有定义，本申请的说明书所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。在本申请的说明书中所使用的术语只是为了描述具体的实施方式的目的，不是旨在于限制本申请。本申请的说明书所使用的术语“及/或”包括一个或多个相关的所列项目的任意的和所有的组合。
离心泵在工作时液体在叶轮的进口处因一定的真空压力会导致自身的绝对压力下降，当液体经压力降后的绝对压力低于液体在该温度下的汽化压力P时，即液体进入离心泵首级叶轮时的绝对压力P a-泵进口压力降NPSHr＜液体的汽化压力P时，液体会发生汽蚀从而影响水泵正常运行甚至损坏水泵；
目前为提高离心泵的汽蚀性能，避免汽蚀的发生，大致可分为提高液体的绝对压力以及减少泵进口的压力降两种思路，其中，
减少泵进口的压力降NPSHr可通过改进流道、叶轮设计等方式实现，能够普遍适用于各类离心泵，但对离心泵汽蚀性能的提升效果相对较小，当输送液体为高温液体时，液体的汽化压力会大幅提升，仅依靠改进流道等方式所带来的泵进口压力降NPSHr的减小，不足以抵消液体汽化压力P的增长量，仍旧会产生汽蚀；
而提高液体的绝对压力P a大多采取在首级叶轮之前增设诱导轮的方式，以增加液体在进入首级叶轮时的绝对压力P a，但加装诱导轮后会增加水泵主轴的长度，从而导致主轴的加工难度上升，同时会导致水泵的运行稳定性下降；
此外，诱导轮在设计时往往需要根据水泵的进口压力降NPSHr等数值进行精密计算，例如：若诱导轮所增加有效汽蚀余量过小，则无法达到避免汽蚀的效果；若诱导轮所增加 的有效汽蚀余量过大，则会导致诱导轮过大，从而导致加工成本过大，水泵运行稳定性较低。
针对上述问题，本申请提供一种水泵进液结构，请参阅图1与图2，该水泵进液结构包括泵座10、泵体20以及连通管30，泵体20位于泵座10上侧且固设于泵座10；泵体20内具有增压腔21，泵座10分别开设有进液口11与出液口12，进液口11与增压腔21的入口连通，出液口12与增压腔21的出口连通，以使得由外界进入进液口11的液体能够在增压腔21的吸力作用下进入增压腔21，并在增压腔21内增压后由出液口12流出；连通管30固设于泵座10内，连通管30的入口与出液口12连通，连通管30的出口与进液口11连通，以使得出液口12内的部分液体能够在进液口11与出液口12之间的压差作用下通过连通管30回流至进液口11。
增压腔21内设置有叶轮等增压部件，能够对流入增压腔21内的液体进行增压，因此液体进入增压腔21时的绝对压力即为液体进入首级叶轮时的绝对压力P a；
待输送的高温液体由进液口11进入泵座10，并通过泵座10进入泵体20内的增压腔21，经过增压腔21的增压后由出液口12输出，且部分增压后的高压液体在出液口12与进液口11之间的压差作用下通过连通管30流入进液口11，与进液口11中的待输送高温液体混合，以提高混合后液体的绝对压力，进而提高液体进入增压腔21时的绝对压力P a，从而减少甚至避免因液体进入增压腔21后的压力降导致发生汽蚀的可能。
在一些实施例中，由外界流入进液口11的液体压力P 1+通过连通管30流入进液口11的液体压力P 2-泵进口的压力降NPSHr＞所输送液体的汽化压力P；
由于进入增压腔21的液体绝对压力P a＝由外界流入进液口11的液体压力P 1+通过连通管30流入进液口11的液体压力P 2(P a＝P 1+P 2)；且为保证液体不会在增压腔21内发生汽蚀，需满足：液体的绝对压力P a-泵进口的压力降NPSHr＞液体的汽化压力P(P a-NPSHr＞P)；
因此，通过满足由外界流入进液口11的液体压力P 1+通过连通管30流入进液口11的液体压力P 2-泵进口的压力降NPSHr＞液体的汽化压力P(P 1+P 2-NPSHr＞P)，能够保证流入增压腔21内的液体不会发生汽蚀，从而达到提高水泵汽蚀性能的效果。
这里，泵进口的压力降NPSHr取决于增压腔21内增压部件的结构，如首级叶轮的流道结构等，为外部环境参数；由外界流入进液口11的液体压力P 1同样为外部环境参数；而液体的汽化压力P取决于液体温度以及种类，同样为外部环境参数；
因此，为提高泵的汽蚀性能，避免汽蚀发生，只能提高通过连通管30流入进液口11 的液体压力P 2。
当本申请的水泵进液结构用于微小锅炉的给水时，所输送液体为180度的高温高压水，其汽化压力P为1Mpa，由外界流入进液口11时的液体压力P 1为0.3Mpa，在图1所示的实施例中的水泵，其泵进口的流速通常为0.7m/s～0.9m/s，故泵进口的压力降NPSHr约2m，即0.02Mpa；
因此，通过连通管30流入进液口11的液体压力P 2需要大于0.72Mpa，以保证高低压混合后的液体在经过增压腔21的压力降后，绝对压力P a仍大于其汽化压力P，进而达到避免汽蚀发生的效果。
在一些实施例中，出于安全考虑，液体的绝对压力P a通常会预留至少0.5m，即0.005Mpa的安全余量，因此，通过连通管30流入进液口11的液体压力P 2需要大于0.725Mpa。
此外，通过连通管30流入进液口11的液体压力P 2受出液口12处的流量、出液口12处的压力以及连通管30的口径等因素的综合影响；
在上述通过连通管30流入进液口11的液体压力P 2为0.72Mpa的实施例中，结合图1所示的实施例中的水泵出液口12处的流量数值及压力数值等因素进行计算后，连通管30的内管壁直径为3mm～5mm；在此连通管30口径下，能够保证通过连通管30流入进液口11的液体压力P 2大于0.72Mpa。
可选的，连通管30的内管壁直径为3mm，以使得通过连通管30流入进液口11的液体压力P 2大于0.72Mpa的同时，能够相对减少回输至进液口11处的高压液体，从而使得大部分高压液体能够从出液口12输出，进而能够达到提高水泵出液效率的效果。
当然，连通管30的内管壁直径也可以选取其他数值，只要对应的出液口12处的流量以及压力下，通过连通管30流入进液口11的液体压力P 2能够大于实际所需的压力即可；
例如，在所需压力保持0.72Mpa不变的情况下，若出液口12处的流量增加，压力不变，则连通管30的口径需要相应增大；而当出液口12的压力增大，流量不变时，则所需的连通管30的口径能够相应缩小。
在图1所示的实施例中，泵座10还具有混合腔13，混合腔13的入口与进液口11连通，混合腔13的出口与增压腔21连通；由外界直接输入的低压液体与由连通管30回输的高压液体能够在混合腔13进行充分混合，以避免高低压液体因混合不足导致出现两级分化，即出现高压低压两种区域，从而破坏液体的流态。
在图2所示的实施例中，混合腔13的中轴线与增压腔21的中轴线共线；连通管30的一端位于混合腔13的入口，且与混合腔13的中轴线共线；以使得进液口11的出口、混合腔13的进口及出口、增压腔21的进口以及连通管30的出口均共线，从而保证通过进 液口11由外界输入的低压液体、由连通管30回输的高压液体以及混合后经增压腔21输出的混合液体，三者的流向相同；一方面避免输入的低压与高压液体相互碰撞导致紊流，另一方面避免上述三种液体与泵座10的内壁碰撞导致能量损耗。
在图1所示的实施例中，混合腔13的入口直径小于出口直径；由于外界输入的低压液体通过混合腔13的入口输入混合腔，而连通管30的一端位于混合腔13的入口，即低压液体与高压液体于混合腔13的入口处汇合，因此通过减小混合腔13的入口，相较于口径较大的入口，能够使得低压与高压液体充分接触并混合，增加混合效果，避免高低压两极分化，破坏液体的流态。
在图1所示的实施例中，混合腔13的入口口径为16mm，出口口径与增压腔21内首级叶轮的入口口径相同，均为37mm。
在图1所示的实施例中，泵座10还包括导流部15，导流部15远离出液口12一侧的表面自上往下向靠近增压腔21中轴线的方向倾斜，且该侧表面配合泵座10的内壁形成导流腔16；导流部15靠近出液口12的另一侧表面配合泵座10的内壁形成混合腔13；导流部15的两侧表面之间平滑过渡。
进液口11包括导流腔16和混合腔13，导流腔16的一端与混合腔13的入口连通；由外界进入泵座10内的液体，会在导流腔16的导向作用下沿导流腔16平滑流动，以避免液体与泵座10内壁碰撞导致能量损失；
此外，导流腔16的出口方向与连通管30的出口方向一致，以使得由外界输入的低压液体与由连通管30回输的高压液体的流向相同，从而避免高低压液体因相互碰撞导致紊流或导致能量损失。
在一些实施例中，连通管30的入口与出液口12交错设置；这里的交错设置，指连通管30的入口与出液口12在位于两者中心的竖直平面的投影无相交。
通过将连通管30的入口与出液口12交错设置，能够减少因连通管30的分流输出对出液口12的液体输出所造成的干扰，从而有效减小出液口12输出液体的压力的降低量，从而在满足高温液体输送需求的同时，避免水泵扬程大幅降低。
在图1所示的实施例中，连通管30的入口位于出液口12下侧；连通管30自入口处向远离泵体20的一侧倾斜，且与水平面之间的夹角为8°；如此设置，以使得由增压腔21流至出液口12的部分高压液体，能够较为平滑地流入连通管30并回输至进液口11，从而避免回输的高压液体与泵座10的内壁发生碰撞，减少高压液体的能量损失。
在图1所示的实施例中，泵座10的表面还开设有多个铸造孔14，以使得泵座10的壁厚均匀，从而在满足铸造需求的同时降低泵座10的铸造成本。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对申请专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请的专利保护范围应以所附权利要求为准。

Claims (10)

  1. 一种水泵进液结构，其特征在于，包括泵座、泵体以及连通管，所述泵体位于所述泵座上侧且固设于所述泵座；
    所述泵体内具有增压腔，所述泵座分别开设有进液口与出液口，所述进液口与所述增压腔的入口连通，所述出液口与所述增压腔的出口连通，以使得由外界进入所述进液口的液体能够在所述增压腔的吸力作用下进入所述增压腔，并在所述增压腔内增压后由所述出液口流出；
    所述连通管固设于所述泵座内，所述连通管的入口与所述出液口连通，所述连通管的出口与所述进液口连通，以使得所述出液口内的部分液体能够在所述进液口与所述出液口之间的压差作用下通过所述连通管回流至所述进液口。
  2. 根据权利要求1所述的水泵进液结构，其特征在于，由外界流入所述进液口的液体压力P 1与通过所述连通管流入所述进液口的液体压力P 2之和大于所输送液体的汽化压力P。
  3. 根据权利要求2所述的水泵进液结构，其特征在于，通过所述连通管流入所述进液口的液体压力P 2大于0.72Mpa。
  4. 根据权利要求3所述的水泵进液结构，其特征在于，所述连通管的内管壁直径为3mm～5mm。
  5. 根据权利要求1所述的水泵进液结构，其特征在于，所述泵座还具有混合腔，所述混合腔的入口与所述进液口连通，所述混合腔的出口与所述增压腔连通。
  6. 根据权利要求5所述的水泵进液结构，其特征在于，所述混合腔的中轴线与所述增压腔的中轴线共线；所述连通管的一端位于所述混合腔的入口，且与所述混合腔的中轴线共线。
  7. 根据权利要求5所述的水泵进液结构，其特征在于，所述混合腔的入口直径小于出口直径。
  8. 根据权利要求5所述的水泵进液结构，其特征在于，所述泵座还包括导流部，所述导流部远离所述出液口一侧的表面自上往下向靠近所述增压腔中轴线的方向倾斜，且该侧表面配合所述泵座的内壁形成导流腔；
    所述导流部靠近所述出液口的另一侧表面配合所述泵座的内壁形成所述混合腔；
    所述导流部的两侧表面之间平滑过渡。
  9. 根据权利要求1所述的水泵进液结构，其特征在于，所述连通管的入口与所述出液口交错设置。
  10. 根据权利要求9所述的水泵进液结构，其特征在于，所述连通管的入口位于所述出液口下侧；所述连通管自入口处向远离所述泵体的一侧倾斜，且与水平面之间的夹角为8°。
PCT/CN2022/076325 2022-01-28 2022-02-15 水泵进液结构 WO2023142177A1 (zh)

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