CN102359633A - Water flow servo valve used for constant pressure - Google Patents

Abstract

The invention relates to a constant pressure water flow servo valve for realizing multi-stage constant pressure irrigation, comprising: a valve body and a diaphragm. The horizontal diaphragm divides the valve body into two parts: a reference pressure chamber and a water flow sensing chamber. There are air outlets, springs, lead screws, and sliders in the cavity. The upper and lower sides of the horizontal diaphragm are respectively covered with stainless steel plates of equal area. The rods are connected together and pass through the center of the diaphragm to coincide with the vertical line of the diaphragm. There is a water outlet in the water flow sensing chamber, and the lower part of the water flow sensing chamber is connected to the water inlet throttle valve. The lower part of the water inlet throttle valve is Circular water inlet channel, the water inlet channel is equipped with three deflectors that are evenly arranged on the inner wall of the circular water inlet channel perpendicular to the circular water outlet section, and the cross-section change curve of the water inlet throttle valve core is calculated or tested. The constant pressure is accurate and reliable, the constant pressure process is fully automatic, the structure is simple, the investment is low, and the installation and use are convenient.

Description

Constant pressure water flow servo valve

Technical field:

The invention belongs to the technical field of farmland irrigation and relates to a constant-pressure water flow servo valve for realizing multi-stage distributed constant-pressure irrigation.

Background technique:

The so-called constant pressure irrigation refers to an irrigation water supply method in which the irrigation water pressure is constant within the optimal water pressure range and does not change due to changes in the irrigation water flow. It has the characteristics of high uniformity of irrigation, less damage to pipeline equipment, water saving, energy saving and high automation.

Because of its unique advantages, constant-pressure irrigation has gained a lot of attention since 1984 when the Institute of Farmland Irrigation of the Chinese Academy of Agricultural Sciences (the Institute of Farmland Irrigation of the Ministry of Water Resources) and other units built the first constant-pressure sprinkler irrigation test project in Jiaxian County, Henan Province. develop by leaps and bounds. The water supply form of constant pressure irrigation has gone through the pressure tank type, the frequency conversion governor type, the frequency conversion speed governor and the small pressure tank combination type, and has developed into multi-functional applications and intelligent control such as soft start, soft shutdown and waterproof hammer. The irrigation method of constant pressure irrigation has also developed from the past sprinkler irrigation to micro sprinkler irrigation and drip irrigation. A flourishing and important branch of the irrigation system gradually formed.

The existing constant pressure irrigation technology generally adopts the system mode of the same water source, the same irrigation form, the same water pressure, and single-stage constant pressure. Because it cannot adapt to most rural areas of our country, the current agricultural production and operation mode of different planting structures, different operating scales, different irrigation methods, and the coexistence of large fields and greenhouses with one household as the business unit greatly limits the application of this advanced technology. Promote apps.

The effective way to solve the above problems is to realize multi-level distributed constant pressure irrigation, and the most critical equipment to realize multi-level distributed constant pressure irrigation with low investment, high reliability and easy management is the constant pressure water flow servo valve.

Invention content:

The object of the present invention is to provide a constant-pressure water flow servo valve for multi-level distributed constant-pressure irrigation with low investment, high reliability and easy management.

The purpose of the present invention is achieved like this:

A constant pressure water flow servo valve, comprising: a valve body, a diaphragm, and the horizontally placed diaphragm divides the valve body into two parts: a reference pressure chamber and a water flow sensing chamber. The reference pressure chamber contains air outlet, spring, screw, Slider, the cross-section of the lead screw is circular and hollow, the upper connecting rod passes through it, the horizontally placed circular slider with a circular vertical hole is placed outside the lead screw, and the two pass through the inner hole of the slider and the lead screw The outer wall is connected by a spiral slideway, the upper part of the upper connecting rod in the hollow lead screw is provided with an air outlet, the top of the lead screw is provided with a cross gap for temporarily installing an adjusting wrench, and the upper and lower sides of the horizontally placed diaphragm are respectively covered with equal-area The stainless steel plate is perpendicular to the plane of the diaphragm, and the upper and lower connecting rods located on the upper and lower sides of the diaphragm are connected together. They pass through the center of the diaphragm and coincide with the vertical line of the diaphragm, and pass through the fastening screws of the upper and lower connecting rods. The stainless steel plate covering the upper and lower sides of the diaphragm is pressed tightly on the diaphragm, the water flow sensing chamber is provided with a water outlet, the lower part of the water flow sensing chamber is connected to the water inlet throttle valve, and the water inlet throttle valve is provided with a water passage section It is a horizontal circular meter-in valve seat and a meter-in valve core whose circular cross-section changes from small to large from top to bottom. The meter-in valve core vertically passes through the horizontal circle of the meter-in valve seat. Shaped cross-section, which coincides with the vertical line of the horizontal circular water-passing section of the meter-in valve seat, and the end of the meter-in valve core with a larger cross-section is located on the water inlet side of the meter-in valve seat. The water-facing surface of the meter-in spool is a circular plane, and the area of the lower stainless steel plate covered by the diaphragm is much larger than the water-facing surface of the meter-in spool. The upper part of the meter-in spool is connected with the lower connecting rod. The lower part of the water inlet throttle valve is a circular water inlet channel, and the water inlet channel is provided with three deflectors that are evenly arranged on the inner wall of the circular water inlet channel perpendicular to the circular water passing section.

The working principle of the constant pressure water flow servo valve of the present invention is as follows:

Because the area of the lower stainless steel plate covered by the diaphragm is much larger than the water-facing surface of the throttle valve core, usually, the pressure on the water-facing surface is much smaller than that of the lower stainless steel plate covered by the diaphragm. The compression caused by the water surface is negligible with reference to the force of the spring in the pressure chamber. When the user stops using water, the water flow rate is the minimum value, the liquid in the water flow sensing chamber stops flowing, the dynamic water pressure is zero, and the hydrostatic pressure is the maximum value (equal to the water outlet pressure H _out ). The pressure on the lower stainless steel plate is the largest, and the generated compression refers to the maximum force of the spring in the pressure chamber (equal to H _out × A _p , where A _p is the area of the lower stainless steel plate covered by the diaphragm), so that the water inlet throttle valve The upward displacement of the core is the largest (equal to the maximum upward displacement s _max of the water inlet throttle valve core, which is marked in the attached drawing); when the user starts to use water, the liquid in the water flow sensing chamber also flows accordingly, and a part of the hydrostatic pressure Converted into dynamic water pressure, the pressure acting on the lower stainless steel plate covered by the diaphragm is reduced, and the generated compression refers to the force of the spring in the pressure chamber is also reduced, and the elastic force of the compressed spring is partially released, so that the water enters The throttle spool moves downward from the maximum upward displacement; the greater the user's water flow rate, the greater the flow rate of the liquid in the water flow sensing chamber, and the more hydrostatic pressure is converted into dynamic water pressure, acting on the diaphragm The lower the pressure on the lower stainless steel plate covered by the upper cover is, the smaller the force of the spring in the compressed reference pressure chamber is, and the more the elastic force of the compressed spring is released, so that the water inlet throttle valve core moves from upward to downward. The distance of the maximum displacement of the downward movement is greater. If expressed in mathematical expressions:

s=f(Q)——1

That is, the displacement s of the water inlet throttle spool is a function of the user water flow Q. More specifically, the displacement s of the water inlet throttle spool is negatively correlated with the user water flow Q.

Because the water inlet channel is connected with the primary constant pressure system, the water inlet pressure H _in is a constant value, the purpose of the constant pressure water flow servo valve is to carry out the secondary constant pressure, the water outlet is connected with the secondary water equipment (user), and the water outlet pressure H _out is also a constant value, and the pressure difference between the front and rear ends of the constant pressure water flow servo valve H _in -H _out is also a constant value, and the constant pressure water flow servo valve satisfies the relational expression:

H _in -H _out ＝S _u Q ² —— 2

In the formula, _Su is the resistance modulus of the constant pressure water flow servo valve; Q is the volume flow of the fluid passing through the valve, that is, the user water flow Q. Because the water resistance of the constant pressure water flow servo valve mainly depends on the resistance of the water inlet throttle valve, _Su can be regarded as the resistance modulus of the water inlet throttle valve. The resistance modulus _Su of the water inlet throttle valve is a function of the area A of the water flow section of the water inlet throttle valve, namely:

S _u =f(A)——3

More specifically, the resistance modulus _Su of the water inlet throttle valve is negatively correlated with the area A of the water flow section of the water inlet throttle valve.

And the area A of the cross-section of the water inlet throttle valve is a function of the displacement s of the water inlet throttle valve core, that is:

A=f(s) ——4

More specifically, the area A of the flow section of the water inlet throttle valve is negatively correlated with the displacement s of the water inlet throttle valve core.

Replace formula 2 with 3 and 4 to get the following formula:

H _in −H _out ＝S _u (f(s))Q ² ——5

Then transform into the following formula:

$<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}$

From formulas 1 and 6, it can be seen that the user water flow Q is a function of the displacement s of the meter-in spool, that is, each change in the user water flow Q corresponds to a displacement of the meter-in spool s, and each change in the displacement s of the throttle spool corresponds to the resistance modulus S _u (f(s)) of a constant pressure water flow servo valve.

According to formula 6, to make the pressure difference H _in -H _out between the front and rear ends of the constant pressure water flow servo valve constant The resistance modulus _Su (f(s)) of the servo valve is inversely proportional to the square of the user's water flow Q.

The spring is selected according to the following formula:

F _max ＝K×s _max +F ₀ ＝H _out ×A _p ——7

In the formula, F _max is the elastic force of the spring at the maximum compression point; K is the elastic modulus of the spring; s _max is the maximum upward displacement of the water inlet throttle valve core (marked in the attached drawing); F ₀ is the initial elastic force of the spring ; H _out is the water outlet pressure of the constant pressure water flow servo valve, that is, the constant value of the user's water pressure; A _p is the area of the lower stainless steel plate covered on the diaphragm. If the selected spring has a deviation, that is, F _max is not equal to H _out × A _p , you can adjust the adjustment wrench temporarily installed on the cross notch on the top of the screw to rotate the screw to move the slider up and down. Compress or loosen the spring until F _max is equal to H _out × A _p , remove the temporary wrench. The purpose of setting this fine-tuning device is to facilitate mass production.

The change curve of the circular cross-section of the water inlet throttle valve core from top to bottom, which changes from small to large, can be developed according to formula 4 and formula 6, and can be obtained by calculation, or by test calibration. The sample of the change curve of the circular cross section of the water throttle valve core from top to bottom from small to large, and then through the method of curve fitting, it is processed and produced in batches by CNC lathe.

The so-called test calibration method is to add a constant pressure source driven by a frequency converter with a pressure of H _in to the water inlet channel, keep H _in at a constant value, install a faucet on the water outlet, and pass through the different openings of the faucet. , to simulate the change of user water flow. For every output flow, by changing the radius of the circular cross-section of the water inlet valve core flush with the horizontal circular water inlet of the water inlet valve seat, the measured water outlet pressure is stabilized at the designed water outlet pressure constant value H _out on. Take the radius of the circular cross-section of a series of meter-in spools obtained as the abscissa x, and the longitudinal displacement of the corresponding meter-in spool as the ordinate y, and draw and connect the lines to obtain the progress A sample of the change curve of the circular cross section of the water throttle spool from small to large from top to bottom.

The present invention has following positive effect:

1. The constant pressure water flow servo valve of the present invention, because of the calculation or test calibration of the change curve of the cross section of the water inlet throttle valve core, and the design of the water inlet deflector, the constant pressure is accurate and reliable;

2. The constant pressure water flow servo valve of the present invention does not need an external drive and control device, the constant pressure process is fully automatic, the structure is simple, the investment is low, and the installation and use are convenient;

3. In the constant pressure water flow servo valve of the present invention, when water hammer occurs in the upper pipeline, the water hammer pressure is transmitted to the spring buffer after being received by the water inlet throttle valve core on the circular surface facing the water, so that the water hammer hazard can be effectively contained .

Description of drawings:

The accompanying drawing is a schematic diagram of the constant pressure water flow servo valve of the present invention.

Detailed ways:

A constant pressure water flow servo valve, as shown in the accompanying drawings, includes: a valve body 1, a diaphragm 2, and the horizontally placed diaphragm 2 divides the valve body 1 into two parts: a reference pressure chamber 3 and a water flow sensing chamber 4. There are air outlet 3-1, spring 3-2, leading screw 3-3, slide block 3-4 in cavity 3, and the cross section of leading screw 3-3 is circular hollow, and upper connecting rod 8-2 wears on Wherein, the horizontally placed circular slider 3-4 with a circular vertical hole is set outside the lead screw 3-3, and the two are connected by the inner hole of the slider 3-4 and the spiral slideway on the outer wall of the lead screw 3-3. The upper part of the upper connecting rod 8-2 in the hollow lead screw 3-3 is provided with an air outlet 3-3-1, and the top of the lead screw 3-3 is provided with a cross gap 3-3-2 for temporarily installing an adjustment wrench, placed horizontally The upper and lower sides of the diaphragm 2 are respectively covered with stainless steel plates 2-1, 2-2 of equal area, perpendicular to the plane of the diaphragm 2, and the upper and lower connecting rods 8-2, 8-2 located on the upper and lower sides of the diaphragm 2 1 are connected together, pass through the center of the diaphragm 2 and coincide with the vertical line of the diaphragm 2, and the stainless steel plates covering the upper and lower sides of the diaphragm 2 will be covered by the fastening screws of the upper and lower connecting rods 8-2 and 8-1 2-1, 2-2 are pressed tightly on the diaphragm 2, and the water flow sensing chamber 4 is provided with a water outlet 4-1, and the lower part of the water flow sensing chamber 4 is connected to a water inlet throttle valve, and the water inlet throttle valve is provided with an overpass. The meter-in valve seat 6 with a horizontal circular water section and the meter-in spool 7 with a circular cross-section that changes from small to large from top to bottom, and the meter-in valve core 7 passes through the meter-in vertically. The horizontal circular cross-section of the valve seat 6 coincides with the vertical line of the horizontal circular cross-section of the meter-in valve seat 6, and the end of the meter-in valve core 7 with a large cross-section is located at the meter-in valve. On the water inlet side of the valve seat 6, the water-facing surface 7-1 of the meter-in spool 7 is a circular plane, and the area of the lower stainless steel plate 2-2 covered on the diaphragm 2 is much larger than the meter-in spool 7. The upper surface of the water inlet 7-1, the upper part of the water inlet throttle valve core 7 is connected with the lower connecting rod 8-1, and the lower part of the water inlet throttle valve is a circular water inlet channel 5, and the water inlet channel 5 is arranged perpendicular to the circular The water passing section is evenly arranged on the three deflectors 5-1 on the inner wall of the circular water inlet channel 5 .

The working principle of the constant pressure water flow servo valve of the present invention is as follows:

As shown in the attached figure, because the area of the lower stainless steel plate 2-2 covered by the diaphragm 2 is much larger than the water-facing surface 7-1 of the throttle valve core 7, under normal circumstances, the pressure received by the water-facing surface 7-1 is also Far less than the pressure borne by the lower stainless steel plate 2-2 covered on the diaphragm 2, the compression generated by the water-facing surface 7-1 can be ignored with reference to the force of the spring 3-2 in the pressure chamber 3. When the user stops using water, the water flow rate is the minimum value, the liquid in the water flow sensing chamber 4 stops flowing, the dynamic water pressure is zero, and the hydrostatic pressure is the maximum value (equal to the water outlet pressure H _out ), at this time, acting on the diaphragm 2 The pressure on the upper covered lower stainless steel plate 2-2 is the largest, and the generated compression refers to the maximum force of the spring 3-2 in the pressure chamber 3 (equal to H _out × A _p , where A _p is the upper covered lower stainless steel plate of the diaphragm 2 2-2), so that the upward displacement of the meter-in spool 7 is the largest (equal to the maximum displacement s _max of the meter-in spool 7, marked in the accompanying drawings); when the user starts to use water, the water flow The liquid in the induction chamber 4 also flows accordingly, and a part of the hydrostatic pressure is converted into a dynamic water pressure, which reduces the pressure acting on the lower stainless steel plate 2-2 covered by the diaphragm 2, and the resulting compression refers to the pressure in the pressure chamber 3. The active force of the spring 3-2 is also reduced accordingly, and the elastic force of the compressed spring 3-2 is partially released, so that the water inlet throttle valve core 7 moves downward from the maximum upward displacement; the greater the water flow of the user, the greater the water flow. The greater the flow rate of the liquid in the induction chamber 4, the more the hydrostatic pressure is converted into the hydrodynamic pressure, and the less pressure acts on the lower stainless steel plate 2-2 covered by the diaphragm 2, and the resulting compression refers to The smaller the force of the spring 3-2 in the pressure chamber 3 is, the more the elastic force of the compressed spring 3-2 is released, so that the water inlet throttle spool 7 moves downward from the maximum upward displacement bigger. If expressed in mathematical expressions:

s=f(Q) - 1

That is, the displacement s of the water inlet throttle spool 7 is a function of the user water flow Q. More specifically, the displacement s of the water inlet throttle spool 7 is negatively correlated with the user water flow Q.

Because the water inlet channel 5 is connected with the primary constant pressure system, the water inlet pressure H _in is a constant value, the purpose of the constant pressure water flow servo valve is to carry out the secondary constant pressure, and the water outlet 4-1 is connected with the secondary water equipment (user) connection, the water outlet pressure H _out is also a constant value, and the pressure difference between the front and rear ends of the constant pressure water flow servo valve H _in -H _out is also a constant value, and the constant pressure water flow servo valve satisfies the relationship:

H _in -H _out ＝S _u Q ² —— 2

In the formula, _Su is the resistance modulus of the constant pressure water flow servo valve; Q is the volume flow of the fluid passing through the valve, that is, the user water flow Q. Because the water resistance of the constant pressure water flow servo valve mainly depends on the resistance of the water inlet throttle valve, _Su can be regarded as the resistance modulus of the water inlet throttle valve. The resistance modulus _Su of the water inlet throttle valve is a function of the area A of the water flow section of the water inlet throttle valve, namely:

S _u =f(A)——3

More specifically, the resistance modulus _Su of the water inlet throttle valve is negatively correlated with the area A of the water flow section of the water inlet throttle valve.

And the area A of the water passing section of the water inlet throttle valve is a function of the displacement s of the water inlet throttle valve core 7, namely:

A=f(s)——4

More specifically, the area A of the water passage section of the water inlet throttle valve is negatively correlated with the displacement s of the water inlet throttle valve core 7 .

Replace formula 2 with 3 and 4 to get the following formula:

H _in −H _out ＝S _u (f(s))Q ² ——5

Then transform into the following formula:

$<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}$

It can be seen from formulas 1 and 6 that the user water flow rate Q is a function of the displacement s of the meter-in spool 7, that is, every change in the user water flow rate Q corresponds to a meter-in spool 7 The displacement s of the water inlet throttle spool 7 corresponds to the resistance modulus S _u (f(s)) of a constant pressure water flow servo valve every time.

According to formula 6, to make the pressure difference H _in -H _out between the front and rear ends of the constant pressure water flow servo valve constant The resistance modulus _Su (f(s)) of the servo valve is inversely proportional to the square of the user's water flow Q.

Spring 3-2 adopts following formula to select:

F _max ＝K×s _max +F ₀ ＝H _out ×A _p ——7

In the formula, F _max is the elastic force of the spring 3-2 at the maximum compression point; K is the elastic modulus of the spring 3-2; s _max is the maximum upward displacement of the water inlet throttle spool 7 (marked in the drawings); F ₀ is the initial spring force of the spring 3-2; H _out is the water outlet pressure of the constant pressure water flow servo valve, that is, the constant water pressure of the user; A _p is the area of the lower stainless steel plate 2-2 covered on the diaphragm 2. If the selected spring has a deviation, that is, F _max is not equal to H _out × A _p , you can rotate the screw 3 by adjusting the adjustment wrench temporarily installed on the cross notch 3-3-2 at the top of the screw 3-3 -3. Make the slider 3-4 move up and down, compress or relax the spring 3-2 until F _max is equal to H _out ×A _p , and remove the temporary wrench. The purpose of setting this fine-tuning device is to facilitate mass production.

The change curve 7-2 of the circular cross-section of the water inlet throttle spool 7 from small to large from top to bottom can be developed according to formula 4 and formula 6, obtained by calculation, or by test calibration , first obtain a sample of the change curve 7-2 of the circular cross-section of the water inlet throttle valve core 7 from top to bottom from small to large, and then perform batch processing and production by a numerically controlled lathe through a curve fitting method.

The so-called test calibration method is to add a constant pressure source driven by a frequency converter with a pressure of H _in to the water inlet channel 5, keep H _in at a constant value, install a water faucet on the water outlet 4-1, and pass the water faucet The different opening degrees simulate the change of the user's water flow. Every time a flow is output, by changing the radius of the circular cross-section of the meter-in valve core 7 that is flush with the horizontal circular water inlet of the meter-in valve seat 6, the measured water outlet pressure is stabilized at the designed water outlet pressure. Value H _out . The radius of the circular cross-section of the obtained series of meter-in spools 7 is taken as the abscissa x, and the longitudinal displacement of the corresponding meter-in spool 7 is taken as the ordinate y, and a line is drawn to obtain A sample of the change curve 7-2 of the circular cross-section of the water inlet throttle spool 7 from small to large from top to bottom is obtained.

Claims (1)

1. A constant pressure water flow servo valve, characterized in that it includes a valve body (1), a diaphragm (2), and the horizontally placed diaphragm (2) divides the valve body (1) into a reference pressure chamber (3) and a water chamber. The two parts of the flow sensing chamber (4) refer to the pressure chamber (3), the air outlet (3-1), the spring (3-2), the lead screw (3-3), the slider (3-4), the wire The cross-section of the bar (3-3) is circular and hollow, and the upper connecting rod (8-2) passes therein, and the circular slide block (3-4) which is placed horizontally has a circular vertical hole and is enclosed within the leading screw ( 3-3), the two are connected by the spiral slideway in the inner hole of the slider (3-4) and the outer wall of the screw (3-3), and the upper connecting rod (8-2) in the hollow screw (3-3) ) is provided with an air outlet (3-3-1), the top of the lead screw (3-3) is provided with a cross notch (3-3-2) for temporary installation of the adjustment wrench, and the top of the horizontal diaphragm (2) , The lower two sides are respectively covered with stainless steel plates (2-1) and (2-2) with equal areas, perpendicular to the plane of the diaphragm (2), and the upper and lower connecting rods (8- 2), (8-1) are connected together, pass through the center of the diaphragm (2) and coincide with the mid-perpendicular line of the diaphragm (2), and pass through the upper and lower connecting rods (8-2), (8-1) The fastening screws compress the stainless steel plates (2-1) and (2-2) covering the upper and lower sides of the diaphragm (2) on the diaphragm (2), and the water flow sensing chamber (4) is provided with a water outlet ( 4-1), the lower part of the water flow sensing chamber (4) is connected to the water inlet throttle valve, and the water inlet throttle valve is provided with a water inlet throttle valve seat (6) with a horizontal circular cross section and a circular cross section The meter-in spool (7) changes from small to large from top to bottom, and the meter-in spool (7) vertically passes through the horizontal circular cross-section of the meter-in valve seat (6). The vertical line of the horizontal circular cross-section of the water throttle valve seat (6) coincides, and the large end of the water inlet throttle valve core (7) cross-section is located at the water inlet side of the water inlet throttle valve seat (6). side, the water-facing surface (7-1) of the meter-in spool (7) is a circular plane, and the area of the lower stainless steel plate (2-2) covered by the diaphragm (2) is much larger than that of the meter-in spool (7) facing the water (7-1), the upper part of the water inlet throttle valve core (7) is connected with the lower connecting rod (8-1), and the lower part of the water inlet throttle valve is a circular water inlet channel (5) , the water inlet channel (5) is provided with three deflectors (5-1) that are evenly arranged on the inner wall of the circular water inlet channel (5) perpendicular to the circular water passing section.

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