Pulse electromagnetic valve control method for reducing water hammer effect

Abstract

The invention discloses a pulse electromagnetic valve control method for reducing a water hammer effect. The pulse electromagnetic valve control method comprises the steps that 1, a water conveying pipeline hydraulic transient calculation model is established; 2, collecting data and checking the hydraulic transient calculation model of the water conveying pipeline; and step 3, repeatedly performing optimization calculation on the control schemes with different valve opening / closing time, counting optimization results, determining the optimal control time, and obtaining a final optimal control scheme. Structural kinematic mechanics and hydraulics principles are applied, a water conveying pipeline hydraulic transient calculation model is established, and the valve opening and closing control effect is achieved by controlling the movement time of a valve cavity, so that pipeline water hammer caused by too fast valve opening or closing, valve loss increase and valve service life reduction can be avoided, and valve opening or closing too slow can be avoided. And a subsequent water using end is influenced, so that water resources are effectively saved, and the regional applicability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water supply system safety and energy conservation, and particularly to a pulse solenoid valve control method for reducing water hammer effect. Background Art

[0002] In a pressure pipeline, due to some external reasons (such as sudden valve closure, sudden stop of a pump unit), the water flow velocity suddenly changes, so that the water flow generates a destructive pressure on the valve and the pipe wall under the action of inertia. This is the "water hammer effect" in hydraulics. The pressure increase caused by the water hammer effect can reach several times or even dozens of times the normal working pressure of the pipeline. Such a large amplitude of pressure fluctuation is likely to cause strong vibration of the pipeline, disconnection of pipeline joints, damage to valves, and in severe cases, pipeline burst, pump reverse rotation and other hazards.

[0003] Our company has applied for a patent with the patent number '202121374850.X' and the patent name 'Structural Improved Large Electromagnetic Pulse Valve'. By setting a small pulse component one and a small pulse component two to control the inflow and cut-off of water, the flexibility of the on-off control of the water inlet chamber and the water outlet chamber is ensured.

[0004] Although this patent uses the method of controlling the inflow and cut-off of water to reduce the adverse effects brought by the water hammer effect, that is, reducing the water hammer effect by delaying the valve opening / closing time. However, this delay time is difficult to control. If the delay time is too long, it will undoubtedly cause waste of water resources, which is not conducive to water conservation and is not applicable to water-scarce areas. But if the extended time is too short, the adverse effects brought by the water hammer effect cannot be reduced. Summary of the Invention

[0005] The purpose of the present invention is to provide a pulse solenoid valve control method for reducing water hammer effect to solve the problems raised in the background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A pulse solenoid valve control method for reducing water hammer effect includes the following steps:

[0008] Step 1, establish a hydraulic transient calculation model for the water conveyance pipeline;

[0009] Step 2, collect data and check the hydraulic transient calculation model for the water conveyance pipeline;

[0010] Step 3, repeatedly perform optimization calculations on control schemes with different opening / closing valve times, count the optimization results, determine the optimal control time, and obtain the finally optimized control scheme.

[0011] Step 1 specifically includes:

[0012] Taking the valve cavity as the basic control volume, the main control forces acting on the valve cavity are the water pressure F1 inside the valve cavity and the elastic force F2 of the spring, i.e., F = ma = F1 + F2

[0013] The motion equation of the valve cavity can be obtained as follows:

[0014] ma = ρghS + kx;

[0015] In the formula, m is the mass of the valve cavity, is the acceleration of motion, S is the force-bearing area inside the valve cavity, ρ is the density of water, g is 9.8 N / kg (usually g = 10 N / kg can be taken), h is the head of the valve cavity, k is the elastic coefficient of the spring, and x is the deformation of the spring.

[0016] When the valve opens, water flows out of the valve cavity and enters the outlet end through the drainage guide pipe. According to the Bernoulli equation principle, we can get:

[0017]

[0018] When the valve closes, water enters the valve cavity from the inlet end through the inlet guide pipe. According to the Bernoulli equation principle, we can get:

[0019]

[0020] In the formula, h is the head of the valve cavity, h a is the head of the inlet guide pipe, h b is the head of the drainage guide pipe, v is the water flow velocity in the valve cavity, v a is the water flow velocity in the inlet guide pipe, v b is the water flow velocity in the drainage guide pipe.

[0021] Therefore,

[0022] When the valve opens, the water pressure inside the valve cavity is:

[0023]

[0024] When the valve closes, the water pressure inside the valve cavity is:

[0025]

[0026] Furthermore, when the water level in the valve cavity reaches the highest value, the water pressure F1 inside the valve cavity is the largest. The sum of the elastic force F2 of the spring and the water pressure F1 inside the valve cavity is in balance with the pressure F3 at the inlet end, and the valve is in the closed state;

[0027] Therefore, when the main valve closes, F = F3 = ρgh u S u , then:

[0028]

[0029] Wherein, S is the force-bearing area inside the valve cavity, S u is the cross-sectional area of the pipeline, ρ is the density of water, g is 9.8 N / kg (usually g = 10 N / kg can be taken), h is the head of the valve cavity, h u is the head at the water inlet end, h b is the head of the drain pipe, v is the flow velocity of the water flow in the valve cavity, v b is the flow velocity of the drain pipe, k is the elastic coefficient of the spring, and x is the deformation of the spring.

[0030] Furthermore, when the valve is opened, the motion equation of the valve cavity is

[0031]

[0032] When the valve is closed, the motion equation of the valve cavity is

[0033]

[0034] Furthermore, by adjusting the flow rates of the water inlet pipe and the drain pipe to form a flow rate difference and control the corresponding flow velocities, the opening and closing speeds of the valve can be controlled.

[0035] Furthermore, the flow rate difference between the water inlet pipe and the drain pipe is 0 - 50%.

[0036] The beneficial effects produced by the present invention are as follows: By applying the principles of structural kinematics and hydraulics, a hydraulic transient calculation model for the water conveyance pipeline is established. By controlling the movement time of the valve cavity, the opening and closing control effect of the valve can be achieved. It can not only avoid water hammer in the pipeline caused by too fast opening or closing of the valve, increase the loss of the valve and reduce the service life of the valve, but also avoid too slow opening or closing of the valve, which has an impact on the subsequent water-using end, effectively saving water resources and increasing the regional applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0038] Figure 1 is a perspective view of the pulse solenoid valve used in the present invention.

[0039] Figure 2 is Figure 1 a sectional view of

[0040] Figure 3 is a pressure change data graph before the control of the present invention.

[0041] Figure 4 This is the pressure change data graph of the water inlet end of the present invention.

[0042] Figure 5 This is the pressure change data graph when the flow rate ratio of water inlet and drainage in the valve cavity is 1:1.

[0043] Figure 6 This is the pressure change data graph when the flow rate ratio of water inlet and drainage in the valve cavity is 5:4.

[0044] Figure 7 This is the pressure change data graph when the flow rate ratio of water inlet and drainage in the valve cavity is 2:1.

[0045] Wherein, 1 - valve body, 11 - large valve core, 12 - large valve cavity, 13 - large spring, 14 - large diaphragm, 2 - valve cover, 3 - pulse component one, 31 - small valve core, 32 - small diaphragm, 33 - small spring, 34 - small valve cavity, 4 - pulse component two, 5 - water inlet end, 6 - water outlet end, 7 - water inlet conduit, 8 - drainage conduit, 9 - pressure sensor Detailed implementation manners

[0046] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] In the claims, the description and the above-mentioned accompanying drawings of the present invention, unless otherwise clearly defined, when using terms such as "first", "second" or "third", etc., are used to distinguish different objects and are not used to describe a specific order.

[0048] In the claims, the description and the above-mentioned accompanying drawings of the present invention, unless otherwise clearly defined, for orientation terms, when using terms such as "center", "horizontal", "longitudinal", "level", "vertical", "top", "bottom", "inner", "outer", "upper", "lower", "front", "rear", "left", "right", "clockwise", "counterclockwise", etc. to indicate the orientation or position relationship, it is based on the orientation and position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, so it cannot be understood as limiting the specific protection scope of the present invention.

[0049] In the claims, the description and the above-mentioned accompanying drawings of the present invention, unless otherwise clearly defined, when using terms such as "fixed connection" or "fixedly connected", should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two, that is, including non-detachable fixed connection, detachable fixed connection, being integrally connected, and being fixedly connected through other devices or elements.

[0050] In the claims, the description and the above-mentioned drawings of the present invention, when the terms "comprising", "having" and their variants are used, are intended to mean "including but not limited to".

[0051] A pulse solenoid valve control method for reducing water hammer effect will be described in detail below.

[0052] Embodiment 1

[0053] A pulse solenoid valve control method for reducing water hammer effect, the pulse solenoid valve used in the control method is as Figure 1-2 shown.

[0054] The pulse solenoid valve includes a valve body 1, a valve cover 2 installed on the valve body 1, and a pulse assembly one 3 and a pulse assembly two 4 integrally connected and installed with the valve cover 2.

[0055] A large valve core 11 is arranged inside the valve body 1, a large valve cavity 12 is formed between the valve cover 2 and the large valve core 11, and a large spring 13 and a large diaphragm 14 are installed in the large valve cavity 12.

[0056] An inlet end 5 and an outlet end 6 are respectively arranged on the left and right sides of the valve body 1; the valve body 1 is connected to the pulse assembly one 3 through an inlet water guide pipe 7 arranged on the outside, and the inlet water guide pipe 7 is arranged at the inlet end 5; the valve body 1 is connected to the pulse assembly two 4 through a drainage water guide pipe 8 arranged on the outside, and the drainage water guide pipe 8 is arranged at the outlet end 6.

[0057] Specifically, the water flow rate accommodated by the inlet water guide pipe 7 is smaller than that of the drainage water guide pipe 8.

[0058] The structures and performances of the pulse assembly one 3 and the pulse assembly two 4 are exactly the same, and are mainly used to cooperate with each other; both include a small valve core 31, a small diaphragm 32 installed on the small valve core 31 and a small spring 33, and the small diaphragm 32 and the small spring 33 form a small valve cavity 34 inside the small valve core 31.

[0059] Specifically, the small valve cavity 34 and the large valve cavity 12 are communicated with each other through a diversion hole.

[0060] Preferably, a pressure sensor 9 can also be arranged at the inlet end / outlet end and / or the top of the valve cavity to monitor the relevant pressure values in real time for convenient correction.

[0061] The valve opening working principle of the valve body 1:

[0062] S1: Receive a valve opening signal;

[0063] S2: Release a signal to the second pulse component according to the signal information within a specified time. The second pulse component is turned on, and water flows out of the small valve cavity, enters the water outlet end through the drain guide pipe. Since the water flow rate of the drain guide pipe is greater than that of the water inlet guide pipe, the pressure balance in the small valve cavity with that in the large valve cavity and the water inlet end is disrupted, and the water in the large valve cavity flows along the diversion hole from the small valve cavity to the water outlet end. Affected by the pressure difference between the water inlet end and the large valve cavity, the large valve core drives the large valve cavity to move upward, away from the water inlet end;

[0064] S3: Release a signal to the first pulse component according to the signal information within a specified time. The first pulse component is closed, and the water at the water inlet end is blocked from entering the large valve cavity. The water volume in the large valve cavity gradually decreases, and the water at the water inlet end pushes open the large valve core through the pressure difference and converges into the water outlet end. The large valve core drives the large valve cavity to move upward. At this time, the entire valve is in an open state.

[0065] The valve closing working principle of the valve body 1:

[0066] S1: Receive a valve closing signal;

[0067] S2: Release a signal to the first pulse component according to the signal information within a specified time. The first pulse component is turned on, and water enters the small valve cavity from the water inlet end through the water inlet guide pipe, and enters the large valve cavity through the diversion hole. Since the water flow rate of the drain guide pipe is greater than that of the water inlet guide pipe, the water pressure in the large valve cavity changes. Affected by the pressure difference between the water inlet end and the large valve cavity, the large valve cavity drives the large valve core to move downward;

[0068] S3: Release a signal to the second pulse component according to the signal information within a specified time. The second pulse component is closed, and the small valve cavity stops draining. As the large valve cavity gradually fills with water, the pressure in the large valve cavity gradually balances with the pressure at the water inlet end, and a negative pressure is generated at the water outlet end 7. The pressure in the large valve cavity plus the thrust of the large spring together push the large valve cavity downward, causing the large valve core to closely adhere to the water inlet end, thereby closing the valve.

[0069] As Figures 3-5 shown, a pulse solenoid valve control method for reducing water hammer effect of the present invention includes the following steps:

[0070] Step 1, establish a hydraulic transient calculation model for the water conveyance pipeline;

[0071] Specifically, step 1 includes:

[0072] To highlight the main influencing factors, the following elements are assumed to be constant:

[0073] 1) Calculate the large valve cavity and the small valve cavity as a whole, named the valve cavity

[0074] 2) Take the volume of the large valve cavity + small valve cavity as a constant variable

[0075] 3) Consider the length and diameter of the water pipes connected to the inlet / outlet as constant variables

[0076] 4) Neglect the self - weight of the valve cavity

[0077] For a method of controlling a pulsed solenoid valve to reduce the water hammer effect according to the present invention, taking the valve cavity as the basic control volume, the main control forces acting on the valve cavity are the water pressure F1 inside the valve cavity and the elastic force F2 of the spring, that is

[0078] F = ma = F1 + F2 (1)

[0079] Among them, F1 = PS = ρghS, where P is the pressure acting inside the valve cavity, S is the force - receiving area inside the valve cavity, ρ is the density of water, and g is 9.8 N / kg (usually g = 10 N / kg can be taken);

[0080] According to Hooke's law, the relationship between the elastic force of the spring and the stroke is: F2 = kx, where: k represents the elastic coefficient of the spring, with the unit of N / m, and x represents the deformation of the spring

[0081] The equation of motion of the valve cavity can be obtained as:

[0082] ma = ρghS + kx; (2)

[0083] In the formula, m is the mass of the valve cavity is the acceleration of motion, S is the force - receiving area inside the valve cavity, ρ is the density of water, g is 9.8 N / kg (usually g = 10 N / kg can be taken), h is the head of the valve cavity, k is the elastic coefficient of the spring, and x is the deformation of the spring

[0084] When the valve opens, water flows out of the valve cavity, passes through the drainage guide pipe and enters the outlet end. According to Bernoulli's equation principle, then:

[0085]

[0086] When the valve closes, water enters the valve cavity from the inlet end through the inlet guide pipe. According to Bernoulli's equation principle, then:

[0087]

[0088] In the formula, h is the head of the valve cavity, h a is the head of the inlet guide pipe, h b is the head of the drainage guide pipe, v is the water flow velocity inside the valve cavity, v a is the water flow velocity of the inlet guide pipe, v b is the water flow velocity of the drainage guide pipe

[0089] Therefore,

[0090] When the valve is open, the water pressure inside the valve chamber is:

[0091]

[0092] When the valve is closed, the water pressure inside the valve chamber is:

[0093]

[0094] When the water level in the valve chamber reaches the maximum value, the water pressure F1 inside the valve chamber is the largest. The elastic force F2 of the spring + the water pressure F1 inside the valve chamber and the pressure F3 at the water inlet end are in a balanced state, and the valve is in the closed state. When the water level in the valve chamber drops, the water pressure F1 inside the valve chamber becomes smaller, driving the valve chamber to rise, and the deformation of the spring becomes smaller, resulting in F2 becoming smaller, and the valve gradually opens. When the water pressure in the valve chamber reaches the lowest point, the valve is fully open. Conversely, when the water pressure in the valve chamber gradually increases, F1 gradually becomes larger, and the valve chamber moves slowly downward under the action of the water pressure + spring force inside the valve chamber, and the valve gradually closes until it is completely closed.

[0095] Therefore, when the main valve is closed, F = F3 = ρgh u S u , then:

[0096]

[0097] In the formula, S is the force-bearing area inside the valve chamber, S u is the cross-sectional area of the pipeline, ρ is the density of water, g is 9.8 N / kg (usually, g = 10 N / kg can be taken), h is the head of the valve chamber, h u is the head at the water inlet end, h b is the head of the drainage guide pipe, v is the water flow velocity inside the valve chamber, v b is the flow velocity of the drainage guide pipe, k is the elastic coefficient of the spring, and x is the deformation of the spring.

[0098] According to equations (1)-(7), it can be obtained that

[0099] When the valve is open, the valve chamber motion equation is

[0100]

[0101] When the valve is closed, the valve chamber motion equation is

[0102]

[0103] According to the relevant motion formulas when the valve is open / closed, establish the functional relationship between the valve chamber pressure and the motion time, and effectively control the pressure inside the valve chamber by controlling the valve chamber motion time, effectively reducing the adverse effects brought by the water hammer effect, and at the same time being beneficial to water conservation.

[0104] Step 2: Collect data and verify the hydraulic transient calculation model of the water conveyance pipeline;

[0105] Specifically, collect relevant data such as the mass, cross-sectional area, height of the valve chamber, radius of the water inlet end, radii of the water inlet conduit and the drainage conduit, and spring elastic coefficient. In the multi-stage valve control scheme, the variations of the valve and valve chamber pressures over time are as Figures 3-5 shown. Among them, the initial state is set as the valve-closed state, the valve movement process is valve-closed - valve-opened - valve-closed, select A and B as the inflection point times for fully opening / closing the valve, that is, the control times of Pulse Module 1 and Pulse Module 2, and 3 s is the switching time of the valve state.

[0106] It should be noted that the selected drawings are one of the random experimental schemes and do not represent all experimental schemes. The opening / closing valve curves of the pipeline model are not unique, but the "valve-closed - valve-opened state" all shows the characteristics of "fast in the early stage, slow in the middle stage, and stable in the later stage", and the "valve-opened - valve-closed state" shows the characteristics of "unchanged in the early stage, fast in the middle stage, and falling back in the later stage", which can be selected according to the actual situation in engineering practice.

[0107] Step 3: Repeat the optimization calculation for control schemes with different opening / closing valve times, statistically analyze the optimization results, determine the optimal control time, and obtain the finally optimized control scheme.

[0108] Embodiment 2

[0109] This embodiment is an improvement of Embodiment 1 and is a refinement of the flow values of the drainage conduit and the water inlet conduit in Embodiment 1.

[0110] By providing a micro-regulating valve in the drainage conduit and / or the water inlet conduit to adjust the flow rate flowing into / out of the valve chamber, so as to control the opening and closing speed of the valve. The micro-regulating valve can use a needle valve.

[0111] Specifically, the relevant data of the difference between the flow rate of the water inlet conduit and the flow rate of the drainage conduit and the pressure are as Figures 5-7 shown.

[0112] The present invention has been described in detail with reference to the accompanying drawings and embodiments. Those of ordinary skill in the art can make various variations to the present invention according to the above description. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the scope of the invention protection of the present invention.

Claims

1. A method for controlling a pulsed solenoid valve to reduce water hammer effect, characterized in that, it includes the following steps: Step 1, establish a hydraulic transient calculation model for the water conveyance pipeline; Step 2, collect data and check the hydraulic transient calculation model for the water conveyance pipeline; Step 3, repeatedly perform optimization calculations on control schemes with different opening / closing valve times, statistically analyze the optimization results, determine the optimal control time, and obtain the finally optimized control scheme. Step 1 specifically includes: Taking the valve cavity as the basic control volume, the main control forces acting on the valve cavity are the water pressure F1 inside the valve cavity and the elastic force F2 of the spring, that is, F = ma = F1 + F2 The motion equation of the valve cavity can be obtained as: ma = ρghS + kx; Where m is the mass of the valve chamber, is the acceleration of motion, S is the force-bearing area inside the valve chamber, ρ is the density of water, g is 9.8 N / kg (usually g = 10 N / kg can be taken), h is the head of the valve chamber, k is the elastic coefficient of the spring, and x is the deformation of the spring. When the valve opens, water flows out of the valve cavity and enters the outlet end through the drain pipe. According to the Bernoulli equation principle, it can be obtained that: When the valve closes, water enters the valve cavity from the inlet end through the inlet pipe. According to the Bernoulli equation principle, it can be obtained that: where h is the head of the valve chamber, h a is the head of the water inlet conduit, h b is the head of the drain conduit, v is the flow velocity of the water in the valve chamber, v a is the flow velocity of the water inlet conduit, v b is the flow velocity of the drain conduit. Therefore, When the valve opens, the water pressure inside the valve cavity is: When the valve closes, the water pressure inside the valve cavity is:

2. The method according to claim 1, characterized in that: When the water level in the valve cavity reaches the maximum value, the water pressure F1 inside the valve cavity is the largest. The elastic force F2 of the spring + the water pressure F1 inside the valve cavity and the pressure F3 at the inlet end are in a balanced state, and the valve is in the closed state; Therefore, when the main valve is closed, F = F3 = ρgh u S u , then: Wherein, S is the force area inside the valve chamber, S u is the cross-sectional area of the pipeline, ρ is the density of water, g is 9.8 N / kg (usually, g = 10 N / kg can be taken), h is the head of the valve chamber, h u is the head of the water inlet end, h b is the head of the drainage guide pipe, v is the water flow velocity in the valve chamber, v b is the flow velocity of the drainage guide pipe, k is the elastic coefficient of the spring, and x is the deformation of the spring.

3. The method according to claim 2, characterized in that, the motion equation of the valve cavity is: When the valve opens, the motion equation of the valve cavity is When the valve closes, the motion equation of the valve cavity is 4. The method according to claim 1, characterized in that: By adjusting the flow rates of the inlet pipe and the drain pipe, a flow rate difference is formed to control the corresponding flow velocity, thereby controlling the opening and closing speed of the valve.

5. The method according to claim 4, characterized in that: The flow rate difference between the inlet pipe and the drain pipe is 0 - 50%.

Images