CN110735800B - Micro-resistance slow-closing check valve and operation method thereof - Google Patents

Micro-resistance slow-closing check valve and operation method thereof Download PDF

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Publication number
CN110735800B
CN110735800B CN201911162223.7A CN201911162223A CN110735800B CN 110735800 B CN110735800 B CN 110735800B CN 201911162223 A CN201911162223 A CN 201911162223A CN 110735800 B CN110735800 B CN 110735800B
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China
Prior art keywords
valve
pipe
pump
pressure
piston
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CN201911162223.7A
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CN110735800A (en
Inventor
严登丰
王建明
白继中
陆伟刚
李彦军
董向前
范永胜
严汉辰
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Yangzhou Jiangtian Flow Instrument Co ltd
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Yangzhou Jiangtian Flow Instrument Co ltd
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Priority to CN201911162223.7A priority Critical patent/CN110735800B/en
Publication of CN110735800A publication Critical patent/CN110735800A/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D15/00—Control, e.g. regulation, of pumps, pumping installations or systems
    • F04D15/0005—Control, e.g. regulation, of pumps, pumping installations or systems by using valves
    • F04D15/0022—Control, e.g. regulation, of pumps, pumping installations or systems by using valves throttling valves or valves varying the pump inlet opening or the outlet opening
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K15/00—Check valves
    • F16K15/02—Check valves with guided rigid valve members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K27/00—Construction of housing; Use of materials therefor
    • F16K27/08—Guiding yokes for spindles; Means for closing housings; Dust caps, e.g. for tyre valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
    • F16K3/02—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with flat sealing faces; Packings therefor
    • F16K3/0218—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with flat sealing faces; Packings therefor with only one sealing face
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
    • F16K3/30—Details
    • F16K3/312—Line blinds
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K47/00—Means in valves for absorbing fluid energy
    • F16K47/02—Means in valves for absorbing fluid energy for preventing water-hammer or noise

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Check Valves (AREA)

Abstract

The invention relates to a micro-resistance slow-closing check valve and an operation method thereof, belonging to the field of mechanical fluid conveying equipment, and comprising a valve tube, a valve cylinder, a valve tube valve plate and a piston body, wherein the valve cylinder is vertical and fixed on the outer wall of the valve tube, a valve cover piston body is arranged at the top of the valve cylinder and is arranged in the valve cylinder, an inner cavity of the valve cylinder is divided into an upper valve cavity and a lower valve cavity, the bottom of the piston body is connected with the valve tube valve plate, and the valve tube is provided with a valve tube communication hole communicated with the valve cylinder; after the pump is started, the valve pipe communication hole injects high-pressure water into the lower valve cavity, and before the upper valve cavity is communicated with the pump, enough pressure difference is formed at two sides of the piston body, so that the piston body is pushed to drive the valve pipe valve plate to move upwards; after stopping the pump, the upper valve cavity is communicated with the valve, the pressure difference between the two sides of the piston body is formed, and under the action of dead weight, the valve pipe valve plate is returned to the valve pipe valve plate groove. The invention has simple structure and convenient manufacture and installation; the resistance loss is very small, which is beneficial to energy saving; after the pump is stopped, the two stages of closing can be realized after the pump is stopped, thereby avoiding the pump from being stopped for escaping and being beneficial to preventing or weakening the damage of water hammer.

Description

Micro-resistance slow-closing check valve and operation method thereof
Technical Field
The invention relates to a micro-resistance slow-closing check valve and an operation method thereof, belongs to the field of mechanical fluid conveying equipment, and is mainly used for pump outlet pressure pipelines of pump stations of water conservancy, municipal engineering and the like.
Background
The pump outlet of pump stations for water conservancy and municipal engineering is provided with a gate valve, a check valve and a high-lift pump, and a water hammer eliminator is arranged. When the pump outlet is only provided with a gate valve, even an electric gate valve, the pump is stopped and the valve is closed slowly, so that the water pump can be in harmful runaway (free inversion) or excessively long runaway time. The pump outlet is provided with a common swing type or lifting type check valve, although the door can be closed by accelerating, the water pump is prevented from flying away, the check valve is internally provided with a valve plate, the normal running resistance loss is large, and the energy consumption is serious; meanwhile, if the valve is closed too quickly, destructive impact can be generated, and a pipeline water hammer can be generated or aggravated. The common water hammer eliminator of the high-lift pump has the advantages of complex structure, high cost, large resistance loss and serious energy consumption.
In 1975, month 8, U.S. patent discloses a swing check valve (publication No. US 3897804A). The valve body of the check valve is a spherical shell with a pipe joint, a cylinder with a cover plate is welded outside the valve body, a hinged swing valve clack is arranged at the joint of an upstream pipe in the valve body, and a control mechanism is arranged in the cylinder to control the opening angle of the valve clack. But it has the following problems:
① Although the valve clack is controllable, the hydraulic loss of the valve clack is reduced, the area change of the flow passage of the valve body section is large, the hydraulic loss is large, and the valve has no superiority;
② The valve body and the control mechanism have complex structures;
③ The valve is too slow to prevent the water pump from flying off without speed regulating function, and the valve is easy to cause water hammer and impact after being blocked.
In 1994, jiangsu agricultural college disclosed an invention patent of "no-resistance automatic check valve and method of use" (patent number: 91104789.1). The check valve has a valve plate groove, hydraulic loss still exists, the check valve is not an unobstructed check valve actually, and the following problems exist:
① The valve body is in a volute shape, the processing and the assembly are complex, and the sealing requirements are difficult to ensure;
② The gravity moment of the bearing element is towards the starting direction in the normal operation of the check valve, so that the shut-down valve needs to have reliable valve closing external moment, such as a torsion spring and the like are additionally arranged at the hinge shaft of the arc plate, and the structure is complex;
③ The check valve has no speed regulation function, and the water pump is difficult to fly away and the pipeline is hard to strike in the valve closing process.
In 2013, yitai real Co., ltd., lin Qingxiong, yitai (Nanjing) environmental protection technology Co., ltd., disclosed an utility model patent of a check valve (patent No. CN 201220701772.4). The check valve comprises an inlet end, a valve body and an outlet end, wherein the inlet end is communicated with the valve body, the valve body is hollow and cylindrical, the outlet end is conical in curved surface, one end of the outlet end is communicated with the valve body, and the other end of the outlet end is closed. The inlet end, the valve body and the outlet end of the check valve are made of elastic materials, and the purpose of preventing water drops from splashing when the filter element is separated from the head of the water purifier is achieved through structural design and material selection of the valve body and the outlet end. The check valve is different from the application occasion of the utility model and is not suitable for being arranged on a pump outlet pipeline.
2016, Miao Yi discloses an utility model patent of a simple check valve for preventing backflow of external water (patent number CN 201520663941.3). The lower part of the check valve body is provided with a funnel-shaped valve seat, the middle part of the valve body is of a cylindrical structure, a spherical valve core is arranged in the cylindrical structure, the valve seat and the valve core are in sealable fit, an inlet connection end is connected below the valve seat, an outlet connection end is arranged on the side edge of the middle part of the valve body, and a valve cover is connected on the upper part of the valve body. The check valve is different from the application occasion of the utility model, and the technical purpose is to provide a simple check valve used in municipal drainage engineering so as to realize the aims of automatic drainage and automatic closure locking of a drainage pipeline, and is not applicable to being installed in a pump outlet pipeline.
In 2017, jiangsu Yongsteel group Co., ltd discloses an invention patent of a buffer impact type check valve (application number CN 201710513084.2). The buffer impact check valve includes: the valve comprises a valve body, a valve cavity, a liquid inlet channel and a liquid outlet channel. A mounting bracket is arranged in the valve cavity above the channel opening at the inner side of the liquid inlet channel, a rocker is hinged on the mounting bracket, and a valve clack is arranged on the rocker. An annular shoulder extending into the valve cavity is arranged above the channel opening at the inner side of the liquid inlet channel, and a balancing counter-punching hole is arranged on the shoulder. In the process of closing the channel opening at the inner side of the liquid inlet channel, the front surface of the valve clack is always provided with pressure, so that the closing time of the valve clack is properly prolonged, and the buffer impact is realized. The buffer impact type check valve has large resistance loss due to the area change of the flow passage and the action of the valve clack; in the process of stopping the pump, the valve clack is in a free falling state and has the function of a reverse water head, and the valve clack is too fast in closing speed and easy to cause a water hammer.
In 2018, dalianda high valve stock company published the patent of the invention of "two-way check valve" (application number CN 201810367719.7). The two-way check valve includes a check valve portion and an instrument shutoff valve portion. Three connecting ends (an inlet end, a middle end and an outlet end) are arranged, and the communication of any two ends is forcedly realized through two instrument stop valves. The two-way check valve is different from the application occasion of the invention and is not suitable for being arranged on a pump outlet pipeline.
In conclusion, the check valve is common mechanical equipment for water conservancy projects, municipal works and other pump station projects. Most of the common check valves are rotary-start type or lifting type, and the common check valves have the defects that:
① Because of the change of the through-flow channel (lifting type) or the shortage of the valve clack Zhang Qi (swing type), the hydraulic loss is large and the energy consumption is serious;
② Based on the working characteristics of the check valve moving part, when the water pump starts and stops, particularly when the pump stops, the valve plate (lifting type) or the valve clack (swing type) is rapidly opened or closed, and harmful impact is easy to generate;
③ The valve plate or the valve clack closes too fast, and a pipeline water hammer is easy to generate or aggravate.
Disclosure of Invention
The invention aims at overcoming the defects of the prior art, and provides a micro-resistance slow-closing check valve and an operation method thereof.
The technical scheme of the invention is as follows:
The invention provides a micro-resistance slow-closing check valve, which is characterized by comprising a valve pipe, a valve cylinder, a valve pipe valve plate and a piston body, wherein the valve pipe is connected to a pump outlet pipeline, a valve pipe valve plate groove for placing the valve pipe valve plate is formed in the valve pipe, the valve cylinder is vertical and fixed on the outer wall of the valve pipe, and a valve cover is arranged at the top of the valve cylinder; the piston body is arranged in the valve cylinder to divide the inner cavity of the valve cylinder into an upper valve cavity and a lower valve cavity, the bottom of the piston body is connected with a valve pipe valve plate, and a valve pipe communication hole communicated with the valve cylinder is arranged in front of a valve pipe valve plate groove; after the pump is started, the valve pipe communication hole injects high-pressure water into the lower valve cavity, the upper valve cavity is communicated with the front part of the pump (the pump inlet), and a large enough pressure difference is formed at two sides of the piston body to push the piston body to drive the valve pipe valve plate to move upwards; after stopping the pump, the upper valve cavity is communicated with the valve, the pressure difference between the two sides of the piston body is formed, and under the action of dead weight, the valve pipe valve plate is returned to the valve pipe valve plate groove.
Preferably, the valve pipe outer wall is provided with a valve pipe binding hoop at a valve pipe valve plate groove, the bottom of the valve pipe binding hoop is provided with an opening, and a valve pipe sand discharging cock is additionally arranged.
Preferably, the upper valve cavity is communicated with the front part (pump inlet) of the pump through a valve cover pump front communication hole and a pump front communication pipe on the valve cover, and the upper valve cavity is communicated with the rear part (valve outlet) of the valve through a valve cover valve rear communication hole and a valve rear communication pipe on the valve cover.
Preferably, the valve cylinder is provided with a pressure distribution valve, the pressure distribution valve is respectively provided with a pressure distribution valve pump front communication hole and a pressure distribution valve back communication hole which correspond to the positions of the valve cover pump front communication hole and the valve cover valve back communication hole, the pump front communication pipe is respectively connected with the pressure distribution valve and the pump front, and the valve back communication pipe is respectively connected with the pressure distribution valve and the valve back.
Preferably, the distributing valve comprises a valve box, a front communicating pipe, a rear communicating pipe, a valve opening pressure-taking pipe and a valve closing pressure-taking pipe, the valve opening pressure-taking pipe and the valve closing pressure-taking pipe are respectively connected to two ends of the valve box, the front communicating pipe and the rear communicating pipe are respectively arranged on the side wall of the valve box, the rear communicating pipe and the valve closing pressure-taking pipe are respectively connected to the rear of the valve, and the front communicating pipe and the valve opening pressure-taking pipe are respectively connected to the front of the pump.
Preferably, a valve box of the pressure distributing valve is internally provided with a pressure distributing valve piston and a spring, the pressure distributing valve piston is arranged in an inner cavity of the valve box, the middle part of the valve box is provided with an annular groove, and the spring is arranged at one end of the pressure distributing valve piston, which is close to the valve opening pressure taking pipe; when the pump is stopped and the valve is closed, the spring presses the pressure distribution valve piston at the valve closing position, and the valve passes through the valve back communicating pipe, the piston annular groove and the valve cover valve back communicating hole, and the upper valve cavity is communicated with the valve; when the pump is started, the pressure in front of the pump is negative, the pressure distributing valve piston compresses the spring under the action of the pressure difference at the two ends of the pressure distributing valve piston, the pressure distributing valve piston moves to the starting position, and the upper valve cavity is communicated with the front of the pump through the pump front communicating pipe, the piston annular groove and the valve cover pump front communicating hole.
Preferably, a speed regulating valve is arranged on the piston body in the valve cylinder.
Preferably, the speed regulating valve comprises a connecting bracket, a speed regulating valve rod, a speed regulating valve plate and a speed regulating valve communication hole; the connecting bracket is fixedly arranged on the piston body, the valve rod of the speed regulating valve is arranged on the connecting bracket, and the bottom of the valve rod of the speed regulating valve is provided with the valve plate of the speed regulating valve; the speed regulating valve communication hole is arranged on the connecting bracket and surrounds the periphery of the speed regulating valve rod; the speed control valve plate is closed or opened by sliding the speed control valve stem up and down.
Preferably, the speed valve plate is provided with a sealing body at one end facing the speed valve communication hole. The valve rod of the speed regulating valve and the valve plate of the speed regulating valve are made of nonmetallic materials with the weight slightly larger than the weight of the conveying fluid.
The second object of the invention is to provide a method for operating a micro-resistance slow-closing check valve, which is characterized in that: when the pump is started, the pump front communicating pipe and the valve opening pressure taking pipe are used for taking the pump front negative pressure, one end of the pressure distributing valve piston is negative in pressure, the other end of the pressure distributing valve piston is provided with larger positive pressure, the pressure distributing valve piston is positioned at the starting position, at the moment, the spring is compressed, and the valve opening pressure difference is formed before the upper valve cavity of the valve cylinder is communicated with the pump through the pump front communicating hole, the annular groove of the pressure distributing valve piston and the pump front communicating pipe.
After the pump is started, high-pressure water is injected into the valve cavity below the valve cylinder through the valve pipe communication hole, and as the pressure difference between two sides of the piston body in the valve cylinder is large enough before the upper valve cavity of the valve cylinder is communicated with the pump, the piston body is pushed to move upwards, and the valve pipe valve plate is pulled out of the valve pipe valve plate groove; when the valve plate of the valve pipe moves upwards and is static, the speed regulating valve is always in a closed state under the action of pressure difference on two sides of the piston body.
When the pump is stopped, the pressure after the valve is obtained by using the valve back communicating pipe and the valve closing pressure obtaining pipe, the valve back pressure is lower than the pressure in the running state by the pump stopping characteristic, and the valve closing pressure difference is formed after the upper valve cavity of the valve cylinder is opened by the valve back communicating hole, the annular groove of the valve closing piston and the valve back communicating pipe under the action of the spring and the valve closing position of the valve closing piston.
When the pump is stopped, the valve rod of the speed regulating valve and the valve plate of the speed regulating valve fall under the action of dead weight, the communication hole of the speed regulating valve opens and overflows, the water body of the upper valve cavity is supplemented, and the descending speed of the piston body is accelerated; when the piston body falls to the end part of the valve rod of the speed regulating valve to contact the outer wall of the valve pipe, the speed regulating valve is gradually closed; meanwhile, after the valve cavity on the valve cylinder is communicated with the valve, the pressure difference between the two sides of the piston body is formed, and under the action of the dead weight of the piston body, the counterweight and the dead weight of the valve pipe valve plate, the valve pipe valve plate is reset, and the valve pipe valve plate groove is gradually closed.
The micro-resistance slow-closing check valve is characterized in that a valve pipe is connected to a pump outlet pipeline, a circular valve plate on the valve pipe is connected with a piston body in a valve cylinder, and a proper counterweight is added to the piston body according to actual needs; in order to accelerate the closing of the pump, a speed regulating valve is arranged on the piston body. The valve tube communication hole is arranged on the valve plate front valve tube, a pressure distributing valve is arranged outside the valve tube, the pressure distributing valve is externally connected with two communication tubes, one is connected with the pump inlet and the other is connected with the valve outlet. The micro-resistance slow-closing check valve is suitable for a water pump and an oil pump.
After the pump is started, high-pressure water is injected into the valve cavity below the valve cylinder through the valve pipe communication hole, and before the valve cavity above the valve cylinder is communicated with the pump, a pressure difference which is large enough at two sides of the piston body is formed, the piston body is pushed to move upwards, and the valve pipe valve plate is pulled out of the valve plate groove; after stopping the pump, after the valve cavity on the valve cylinder is communicated with the valve, the pressure difference between the two sides of the piston body is formed, and under the action of the dead weight of the piston body and the dead weight of the counterweight and the valve pipe valve plate, the valve pipe valve plate is reset, so that the valve is closed.
The speed regulating valve can ensure that the valve plate of the pump stopping initial valve can be quickly reset. In the starting and running process of the pump, the valve plate of the speed regulating valve is closed under the action of the starting pressure difference on two sides of the piston body, the starting pressure difference disappears after the pump is stopped, the speed regulating valve is opened, the water quantity of the valve cavity on the valve cylinder is supplemented together with the communicating pipe behind the connecting valve, the descending speed of the piston body is increased, and the valve plate returns quickly; when the valve is closed, the end part of the valve rod contacts the outer wall of the valve pipe, the speed regulating valve is gradually closed, and the valve plate of the valve pipe is reset in a first-speed-then-slow two-stage way by matching with the backflow area change of the valve pipe valve plate groove, so that the check valve is closed in a first-speed-then-slow two-stage way.
The micro-resistance slow-closing check valve has the following advantages:
1. the micro-resistance slow-closing check valve has simple structure, convenient manufacture and installation and can be used for one valve for multiple purposes;
2. in normal operation of the pump, the valve pipe is only provided with a valve plate groove in the valve pipe, so that no valve plate exists, and the flow resistance loss is very small, thereby being beneficial to energy conservation;
3. When the valve plate of the valve pipe returns to the original position after stopping the pump, the valve plate groove of the valve pipe is changed from large to small in backflow area through the action of the speed regulating valve, so that the valve closing speed is firstly fast and then slow, the water pump is prevented from flying away, and the water hammer of a pipeline is avoided or weakened;
4. The return movement of the valve tube valve plate is controlled by the piston body in the valve cylinder, particularly when the valve is closed, the area of a water return channel of a valve tube valve plate groove is gradually reduced, accumulated water in the valve tube valve plate groove plays a role in buffering, and the contact impact of the valve tube valve plate and the valve tube valve plate groove is avoided.
Drawings
FIG. 1-1 is a side elevational view of a valve body of the micro-resistance slow closing check valve of the present invention;
FIGS. 1-2 are side cross-sectional views of a valve body of a micro-resistance slow-closing check valve of the present invention;
FIGS. 1-3 are front sectional views (valve-closing state) of a valve body of a micro-resistance slow-closing check valve of the present invention;
FIGS. 1 to 4 are front sectional views (open state) of a valve body of a micro-resistance slow-closing check valve of the present invention;
FIG. 2-1 is a diagram showing the constitution of a pressure distribution valve in a micro-resistance slow-closing check valve according to the present invention;
FIG. 2-2 is a sectional view (open state) of a pressure distributing valve in the micro-resistance slow-closing check valve of the present invention;
FIGS. 2-3 are front views of the pressure distribution valve in the micro-resistance slow-closing check valve of the present invention;
FIGS. 2-4 are sectional views (closed state) of the pressure distributing valve in the micro-resistance slow-closing check valve of the present invention;
FIGS. 2-5 are piston diagrams of the pressure distribution valve in the micro-resistance slow-closing check valve of the invention;
FIG. 3 is a diagram of a speed valve in the micro-resistance slow-closing check valve of the invention;
In the figure: valve tube 1, valve tube binding hoop 1-1, valve tube sand discharging cock 1-2, valve tube valve plate groove 1-3, valve tube valve plate groove guide ring 1-4, valve tube communication hole 1-5, valve cylinder 2, valve cover 3, valve cover valve back communication hole 3-1, valve cover pump front communication hole 3-2, pressure distributing valve 4, valve box 4-1, pump front communication pipe 4-2, valve back communication pipe 4-3, valve opening pressure taking pipe 4-4, valve closing pressure taking pipe 4-5, pressure distributing valve piston 4-6, spring 4-7, valve back communication hole 4-8, pump front communication hole 4-9, valve tube valve plate 5, piston body 6, valve plate connecting block 7, piston body guide ring 8, speed regulating valve 9, connecting bracket 9-1, speed regulating valve rod 9-2, speed regulating valve plate 9-3, sealing body 9-4, speed regulating valve communication hole 9-5.
Detailed Description
The micro-resistance slow-closing check valve is suitable for the transient process characteristics of starting and stopping the water pump, after the water pump is started, a valve opening pressure difference with enough two sides of a piston body is formed through the pressure distribution valve, and the valve pipe valve plate is pulled to open the valve steadily and open the valve fully; when stopping the pump, the pressure difference between the two sides of the piston body is formed through the pressure distributing valve, and the valve pipe valve plate is pulled to stably fall under the action of the dead weight of the piston body, the counterweight and the dead weight of the valve pipe valve plate, and the valve is closed at the first stage and the second stage.
It should be noted that: ① If the dead weight of the piston body and the dead weight of the valve plate can reliably meet the return of the valve plate, the piston body can be determined through calculation without adding any counterweight; ② For the low-lift water pump, the pressure distribution valve can be eliminated through calculation and determination in order to simplify the structure of the check valve, and the upper cavity of the valve cylinder is directly communicated with the atmosphere or is connected with the open water tank by a communicating pipe; ③ In order to simplify the structure of the check valve, the speed regulating valve can be omitted after calculation and determination.
1-1 To 1-4, a valve pipe communication hole 1-5 is formed in the pipe wall of the valve pipe 1, and the valve pipe communication hole is communicated with the back of the pump to the lower valve cavity, so that the pressure in the lower valve cavity and the pressure behind the pump are kept to synchronously change. The valve cover 3 is provided with a valve cover valve back communication hole 3-1 and a valve cover pump front communication hole 3-2, the upper valve cavity is communicated with the valve through the pressure distribution valve by the communication hole 3-1, and the upper valve cavity is communicated with the pump front through the pressure distribution valve by the communication hole 3-2. The outer wall of the valve tube 1 is provided with a binding hoop 1-1, the bottom of the binding hoop is provided with an opening, and a cock 1-2 is additionally arranged for discharging sand. The valve tube 1 is provided with a valve tube valve plate groove 1-3, the valve tube valve plate groove is matched with a valve plate groove guide ring 1-4, and the valve plate groove guide ring is made of wear-resistant metal materials. The piston body 6 in the valve cylinder is provided with a piston body guide ring 8 which is made of wear-resistant nonmetallic materials.
The valve tube 1, the valve cylinder 2 and the valve cover 3 form a valve cavity, a piston body 6 is arranged in the valve cavity, a valve cylinder lower valve cavity is formed between the piston body and the valve tube, a valve cylinder upper valve cavity is formed between the piston body and the valve cover, and the piston body is connected with the valve plate 5 through a connecting block 7. The valve cover is provided with a pressure distribution valve 4, and the piston body is provided with a speed regulation valve 9.
Reliability regarding valve opening:
After the water pump is started, the pump outlet pressure is gradually increased, the pressure is maximum when the water pump is in normal operation, and the numerical value (kPa) is as follows: pd=ρg· (hd+hd), where ρ is the fluid density (t/m 3), g is the gravitational acceleration (m/s 2), hd is the net pressure (m), hd is the hydraulic loss (m) of the water outlet pipe, and the lower valve cavity is pumped (pump out) through the valve pipe communication holes 1-5; the inlet of the pump is higher than the water surface of the water inlet tank, the pressure ps is negative in the starting and running process of the pump, the negative pressure is maximum in the normal running process of the pump, the absolute value of the negative pressure is ρg (Hs+hs), hs is the net suction stroke (m), hs is the hydraulic loss (m) of the water suction pipeline, and the upper valve cavity is communicated with the front of the pump through the valve cover pump front communicating hole 3-2 and the distributing valve pump front communicating pipe 4-2. If the valve tube inner diameter D (m), the valve plate and piston body diameters df=d+2δ, δ are the tube wall thicknesses, the lower valve cavity pressure Pd (kN) of the piston body area is pd·ff, the upper valve cavity pressure Ps (kN) is ps·ff, and the valve opening differential pressure Δp (kN) on two sides of the piston body is Pd-ps=ρg· (h+h) ·ff. H is the net pump lift (m), and H is the total hydraulic loss (m) of the pump device. If the pump lift h=20m, the valve-opening pressure difference Δp on both sides of the piston body is >2kN. Because the pressure difference of the valve is far greater than the dead weight of the piston body, the counterweight and the dead weight of the valve plate, the valve is reliably opened.
Reliability regarding valve closing:
According to the transient process characteristics of the water pump, the water pump and the pipeline still flow forward in a short time after the pump is stopped, then the reverse flow is started, and the forward flow and the reverse flow change instantly and afterwards, because the upper valve cavity is communicated with the pump through the valve cover valve back communication hole 3-1 and the distributing valve back communication pipe 4-3, the pressure after the lower valve cavity is communicated with the pump is larger than the pressure after the pump, and the two sides of the piston body form a valve closing pressure difference. In countercurrent, the valve plate is partially closed, causing hydraulic losses, resulting in a differential pressure Δp (kPa). The same pressure difference deltap is also formed across the piston body. Pressure difference Δpf=Δp·ff (kN). The valve tube section area is F (m 2), the valve plate partial closing projection area is smaller than F, and the valve plate pressure difference delta P is naturally smaller than the pressure difference delta Pf at two sides of the piston body. Assuming that the valve plate homing friction resistance is Pm, pm=Δp·f, f is a friction coefficient, and the value is smaller than 1.0, pm is necessarily smaller than Δpf. In addition, when the valve plate is reset, the valve is reliably closed under the actions of dead weight of the piston body, the counterweight and dead weight of the valve plate.
Referring to fig. 2-1 to 2-5, the pressure distributing valve functions in: when the pump is started, the pump front communicating pipe 4-2 and the valve opening pressure taking pipe 4-4 are used for taking the pump front negative pressure, one end of the distributing valve piston 4-6 is negative pressure, the other end of the distributing valve piston is provided with larger positive pressure, and the distributing valve piston is positioned at a starting and running position (at the moment, the spring 4-7 is compressed) and forms valve opening pressure difference before the upper valve cavity is communicated with the pump through the valve cover pump front communicating hole 3-2, the pump front communicating hole 4-9, the distributing valve piston annular groove and the pump front communicating pipe 4-2; when the micro-resistance slow-closing check valve is static and the valve is closed, the pressure after the valve is taken by the valve back communicating pipe 4-3 and the valve closing pressure taking pipe 4-5 is utilized, the pressure after the valve is lower than the pressure in the running state by the pump stopping characteristic, and the pressure is acted by the spring 4-7, the pressure distributing valve piston 4-6 moves to the position of stopping the pump, and the valve closing pressure difference is formed after the upper valve cavity is opened by the valve cover valve back communicating hole 3-1, the valve back communicating hole 4-8, the pressure distributing valve piston annular groove and the valve back communicating pipe 4-3.
Referring to fig. 3, the speed valve functions in: when the micro-resistance slow-closing check valve is in a closed state, the end part of the speed regulating valve rod 9-2 contacts with a main valve pipe, and the speed regulating valve is also in a closed state; when the pump starts the main valve plate to move upwards and still, the main valve plate is still in a closed state under the action of pressure difference on two sides of the piston body. When the pump is stopped, the speed regulating valve rod 9-2 and the speed regulating valve plate 9-3 fall under the action of dead weight, the speed regulating valve communicating hole 9-5 opens the overcurrent, the water body of the upper valve cavity is supplemented, and the descending speed of the piston body is accelerated. The valve rod 9-2 of the speed regulating valve and the valve plate 9-3 of the speed regulating valve fall to have certain stroke limitation, when the piston body falls to the end part of the valve rod 2 of the speed regulating valve to contact with the valve pipe, the speed regulating valve is gradually closed, meanwhile, the valve pipe valve plate groove is gradually closed, the outflow of water in the lower valve cavity is blocked, so that the return speed of the valve pipe valve plate is limited, and the micro-blocking slow-closing check valve is closed in two stages after being firstly fast and then slow.
In order to ensure that the speed regulating valve is closed when the water pump normally operates, the movable part of the speed regulating valve is made of light materials; to ensure that the speed valve opens when the pump is stopped, the material weight of the movable part is slightly larger than the fluid weight. The area of the communication hole 9-5 is determined by calculation according to the valve closing speed requirement.
Example 1-the micro-resistance slow-closing check valve of the present invention is used as a check valve for the outlet of a high-lift centrifugal pump.
When the micro-resistance slow-closing check valve is used for a high-lift centrifugal pump outlet pipeline, flanges at two ends of the valve pipe 1 are connected into the pipeline. Under normal conditions, the centrifugal pump adopts a vacuumizing starting mode, and negative pressure is formed in front of the pump during vacuumizing. Referring to fig. 2-1 to 2-5, the negative pressure before the pump is applied to one end of the pressure distributing valve piston 4-6 through the pump front communicating pipe 4-2 and the valve opening pressure taking pipe 4-4, and the pressure of the pressure distributing valve piston 4-6 is equal to the atmospheric pressure (no water is present after the valve) or greater than the atmospheric pressure (water is present after the valve) after the valve opening is performed on the other end of the pressure distributing valve piston 4-6, and the pressure distributing valve piston 4-6 is moved from the valve closing position to the valve opening position by the compression spring 7 under the action of the pressure difference. Referring to fig. 1-2 and fig. 2-1, the upper valve cavity of the valve cylinder is communicated with the front of the pump through the valve cover pump front communicating hole 3-2, the piston annular groove and the pump front communicating pipe 4-2. After the vacuumizing is finished, water is filled in the pump and the micro-resistance slow-closing check valve, and the water pump can be started after the water filling is finished.
After the water pump is started, the pressure after the pump is gradually increased, and in contrast to fig. 1-1 to 1-4, the high-pressure water after the pump is filled into the lower valve cavity through the valve pipe communication hole 1-5. When the pump is started, before the upper valve cavity is communicated with the pump, the piston body 6 moves upwards against the dead weight of the piston body, the counterweight and the dead weight of the valve pipe valve plate 5 under the action of pressure difference on two sides, and the valve opening state is completed and maintained.
1-1 To 2-5, when the pump is stopped, the pressure behind the valve acts on one end of the pressure distributing valve piston 4-6 through the valve back communicating pipe 4-3 and the valve closing pressure taking pipe 4-5 of the pressure distributing valve, and the pressure difference exists at two ends of the pressure distributing valve piston before the other end of the pressure distributing valve piston is communicated with the pump. However, the water in the valve pipe flows back when the pump is stopped, the pressure behind the valve is smaller than the pressure behind the valve in normal operation, and the pressure before the pump is larger than the pressure before the pump in normal operation when the pump is stopped, so that the pressure difference between two ends of the piston is smaller than the pressure difference in normal operation when the pump is stopped. At this time, the elastic force of the spring 4-7 overcomes the pressure difference at the two ends of the piston and pushes the piston to move to the valve closing position. Referring to fig. 1-1 to 2-5, the valve-back water body is filled into the upper valve cavity through the valve-back communicating pipe 4-3 of the pressure distributing valve, the piston annular groove and the valve-cover valve-back communicating hole 3-1. At this time, the back pressure of the pump of the lower valve cavity is lower than that of the upper valve cavity, and the valve plate returns to close the valve under the action of the dead weight of the piston body, the counterweight and the dead weight of the valve plate. The starting and closing functions of the micro-resistance slow-closing check valve are automatically realized.
1-1 To 3, when the piston body 6 falls, the falling speed of the piston body may be limited by the overflow capacity of the valve back communicating pipe 4-3, the pressure distributing valve piston annular groove and the valve cover valve back communicating hole 3-1, a speed regulating valve is arranged, the area of the communicating hole is reasonably determined, and the valve closing speed can be increased; when the valve is closed, the communication hole is gradually closed, the piston body 6 falls slowly, and the valve plate 5 returns to achieve the completion of the first quick stage and the second slow stage.
Example 2-the micro-resistance slow closing check valve of the present invention is used as a check valve for low lift pump outlets.
When the micro-resistance slow-closing check valve is used for the outlet of a low-lift pump, flanges at two ends of a valve pipe are connected into a pipeline, and the installation is the same as that of the embodiment 1. Referring to fig. 1-1 to 1-4, as long as the head is not too low, the valve plate 5 and the piston body 6 are not too heavy, and it is determined through calculation that the valve plate 3 and the piston body 6 are not provided with a pressure distribution valve, the valve cover valve rear communication hole 3-1 and the valve cover pump front communication hole 3-2 of the valve cover 3 are integrated, and the air is directly introduced, or the communication pipe is used for opening the water tank. If the valve closing speed is not particularly required, a speed regulating valve can be omitted.
Example 3-micro-resistance slow closing check valve of the present invention was used for pump outlet instead of gate valve.
When the gate valve is arranged at the outlet of the pump, the gate valve is opened, closed or manually or electrically operated. The micro-resistance slow-closing check valve has the same function as a gate valve, and only the starting and closing of the valve are automatically realized, so that the micro-resistance slow-closing check valve can be used for replacing the gate valve, and the valve body structure and the installation of the micro-resistance slow-closing check valve are the same as those of the embodiment 1 or the embodiment 2.

Claims (3)

1. The micro-resistance slow-closing check valve is characterized by comprising a valve pipe (1), a valve cylinder (2), a valve pipe valve plate (5) and a piston body (6), wherein the valve pipe is connected to a pump outlet pipeline, a valve pipe valve plate groove (1-3) for placing a valve pipe valve plate is formed in the valve pipe, the valve pipe valve plate groove (1-3) is coaxially arranged with the valve pipe, the valve cylinder is vertical and fixed on the outer wall of the valve pipe, and a valve cover (3) is arranged at the top of the valve cylinder; the piston body is arranged in the valve cylinder to divide the inner cavity of the valve cylinder into an upper valve cavity and a lower valve cavity, the bottom of the piston body is connected with a valve pipe valve plate, and a valve pipe communication hole (1-5) communicated with the valve cylinder is arranged in front of a valve pipe valve plate groove; after the pump is started, the valve pipe communication hole injects high-pressure water into the lower valve cavity, and before the upper valve cavity is communicated with the pump, a large enough pressure difference is formed at two sides of the piston body, so that the piston body is pushed to drive the valve pipe plate to move upwards, and the valve pipe valve plate completely enters the lower valve cavity; after stopping the pump, after the upper valve cavity is communicated with the valve, a valve pressure difference is formed between two sides of the piston body, and under the action of dead weight, the valve pipe valve plate is returned to the valve pipe valve plate groove;
The valve pipe outer wall is provided with a valve pipe binding hoop (1-1) at a valve pipe plate groove, the bottom of the valve pipe binding hoop is provided with an opening, and a valve pipe row Sha Xuansai (1-2) is additionally arranged;
the upper valve cavity is communicated with the front part of the pump through a valve cover pump front communication hole (3-2) and a pump front communication pipe (4-2) on the valve cover, and is communicated with a valve barrel behind a valve plate groove through a valve cover valve rear communication hole (3-1) and a valve rear communication pipe (4-3) on the valve cover;
The valve cylinder is provided with a pressure distribution valve (4), the pressure distribution valve is respectively provided with a pressure distribution valve pump front communication hole (4-9) and a pressure distribution valve back communication hole (4-8) which correspond to the valve cover pump front communication hole and the valve cover valve back communication hole in position, the pump front communication pipe is respectively connected with the pressure distribution valve and the pump front, and the valve back communication pipe is respectively connected with the pressure distribution valve and the valve back;
The pressure distribution valve comprises a valve box (4-1), a front communicating pipe (4-2), a rear communicating pipe (4-3), a valve opening pressure taking pipe (4-4) and a valve closing pressure taking pipe (4-5), wherein the valve opening pressure taking pipe and the valve closing pressure taking pipe are respectively connected to two ends of the valve box, the front communicating pipe and the rear communicating pipe are respectively arranged on the side wall of the valve box, the rear communicating pipe and the valve closing pressure taking pipe are respectively connected to the rear of the valve, and the front communicating pipe and the valve opening pressure taking pipe are respectively connected to the front of the pump;
A valve box of the pressure distributing valve is internally provided with a pressure distributing valve piston (4-6) and a spring (4-7), the pressure distributing valve piston is arranged in an inner cavity of the valve box, the middle part of the valve box is provided with an annular groove, and the spring is arranged at one end of the pressure distributing valve piston, which is close to the valve opening pressure taking pipe; when the pump is stopped and the valve is closed, the spring presses the pressure distribution valve piston at the valve closing position, and the valve is opened through the valve back communicating pipe (4-3), the piston annular groove and the valve cover valve back communicating hole (3-1); when the pump is started, the pressure in front of the pump is negative, the pressure distribution valve piston compresses the spring under the action of pressure difference at two ends of the pressure distribution valve piston and moves to a starting position, and the upper valve cavity is communicated with the front of the pump through the front communicating pipe (4-2), the piston annular groove and the front communicating hole (3-2) of the valve cover;
A speed regulating valve (9) is arranged on a piston body in the valve cylinder and comprises a connecting bracket (9-1), a speed regulating valve rod (9-2), a speed regulating valve plate (9-3) and a speed regulating valve communication hole (9-5); the connecting bracket is fixedly arranged on the piston body, the valve rod of the speed regulating valve is arranged on the connecting bracket, and the bottom of the valve rod of the speed regulating valve is provided with the valve plate of the speed regulating valve; the speed regulating valve communication hole is arranged on the connecting bracket and surrounds the periphery of the speed regulating valve rod; the speed control valve plate is closed or opened by sliding the speed control valve stem up and down.
2. The micro-resistance slow-closing check valve according to claim 1, wherein a sealing body (9-4) is arranged at one end of the speed valve plate facing the speed valve communication hole, and the speed valve rod (9-2) and the speed valve plate (9-3) are made of nonmetallic materials with the weight slightly larger than the weight of the conveying fluid.
3. The method for operating a micro-resistance slow-closing check valve according to claim 1, wherein the method comprises the following steps:
When the pump is started, the pump front communicating pipe (4-2) and the valve opening pressure taking pipe (4-4) are used for taking the pump front negative pressure, one end of the pressure distributing valve piston (4-6) is negative, and the other end of the pressure distributing valve piston is provided with larger positive pressure, so that the pressure distributing valve piston is positioned at the starting position, at the moment, the spring (4-7) is compressed, and the valve opening pressure difference is formed before the upper valve cavity of the valve cylinder is communicated with the pump through the pump front communicating pipe (4-9), the annular groove of the pressure distributing valve piston (4-6) and the pump front communicating pipe (4-2);
After the pump is started, high-pressure water is injected into the lower valve cavity of the valve cylinder through the valve pipe communication hole (1-5), and as the pressure difference between two sides of the piston body in the valve cylinder is large enough before the upper valve cavity of the valve cylinder is communicated with the pump, the piston body is pushed to move upwards, and the valve pipe valve plate is pulled out of the valve pipe valve plate groove (1-3); when the valve plate of the valve pipe moves upwards and is static, the speed regulating valve is always in a closed state under the action of pressure difference on two sides of the piston body;
When the pump is stopped, the pressure after the valve is taken by using the valve back communicating pipe (4-3) and the valve closing pressure taking pipe (4-5), the pressure after the valve is lower than the pressure in the running state by the characteristic of stopping the pump, and the pressure distributing valve piston is at the valve closing position under the action of a spring, and the valve closing pressure difference is formed after the upper valve cavity of the valve cylinder is opened by the valve back communicating hole (4-8), the annular groove of the pressure distributing valve piston (4-6) and the valve back communicating pipe (4-3);
When the pump is stopped, the valve rod of the speed regulating valve and the valve plate of the speed regulating valve fall under the action of dead weight, the communication hole of the speed regulating valve opens and overflows, the water body of the upper valve cavity is supplemented, and the descending speed of the piston body is accelerated; when the piston body falls to the end part of the valve rod of the speed regulating valve to contact the outer wall of the valve pipe, the speed regulating valve is gradually closed;
Meanwhile, after the valve cavity on the valve cylinder is communicated with the valve, the pressure difference between the two sides of the piston body is formed, and under the action of the dead weight of the piston body, the counterweight and the dead weight of the valve pipe valve plate, the valve pipe valve plate is reset, and the valve pipe valve plate groove is gradually closed.
CN201911162223.7A 2019-11-25 2019-11-25 Micro-resistance slow-closing check valve and operation method thereof Active CN110735800B (en)

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CN211116671U (en) * 2019-11-25 2020-07-28 扬州江天流量仪表有限公司 Novel micro-resistance slow-closing check valve

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