Micro-power pilot valve with conical surface valve element and optimization design method of micro-power pilot valve

Abstract

The invention discloses a micro-power pilot valve with a conical surface valve element and an optimization design method of the micro-power pilot valve, and belongs to the technical field of pressure reducing valves. Firstly, the water inlet and outlet flow speed of a pilot upper cavity is calculated based on the Bernoulli equation and the Darcy-Weistbach formula, and then the minimum water inlet and outlet volume of the pilot upper cavity is obtained; and the minimum action stroke of the upper diaphragm is calculated. And the minimum through-flow area of the conical surface valve element is determined, and the constraint condition of the minimum opening degree of the pilot valve is constructed based on the mechanical balance relation between the pressure of the upper cavity of the main pressure reducing valve and the conical surface valve element, so that the pilot valve meets the adjusting requirement under the extreme working condition. And obtaining the maximum stroke of the pilot valve based on the fact that the equivalent through-flow area of the maximum stroke of the pilot valve is equal to the through-flow area of the pilot valve pipeline. The system systematically solves the bottlenecks of a traditional pilot-operated type pressure reducing valve in the aspects of dynamic response, energy dependence, adjusting precision and flow management, and has good practicability.

Description

Technical Field

[0001] This invention belongs to the technical field of pressure reducing valves, specifically relating to a micro-powered pilot valve with a conical valve core and its optimized design method. Background Technology

[0002] A pilot-operated pressure reducing valve is a hydraulic or pneumatic control element that controls the operation of the main pressure reducing valve through changes in the pressure of the pilot chamber. It is widely used in industrial automation, engineering machinery, and hydraulic support systems in coal mines. The core advantage of a pilot-operated pressure reducing valve lies in using a small-flow pilot signal to adjust the large-flow output pressure of the main pressure reducing valve, thereby achieving precise control of the system pressure.

[0003] Existing pilot-operated pressure reducing valves mostly rely on adjusting spring pins or mechanical adjustment mechanisms to change spring deformation and set the pressure. However, traditional pin-type pressure reducing valves require frequent manual operation of the spring pin when adjusting the pressure, which can easily lead to spring pin failure. Mechanically adjustable pressure reducing valves face two major challenges: firstly, the mechanical mechanism is prone to failure or malfunction due to long-term use; secondly, their adjustment power requirements are relatively high, such as relying on mains power, which limits their engineering applications. In addition, mechanically adjustable pressure reducing valves also suffer from insufficient adjustment accuracy, and the flow area of ​​the valve core exhibits non-linear characteristics, further reducing the accuracy of pressure regulation. Summary of the Invention

[0004] The purpose of this invention is to provide a micro-powered pilot valve with a conical valve core and its optimized design method, in order to solve the above-mentioned problems.

[0005] This invention is mainly achieved through the following technical solutions:

[0006] A micro-powered pilot valve with a conical valve core includes a valve body, an upper diaphragm, a lower diaphragm, and a conical valve core. The upper and lower diaphragms are slidably disposed at the upper and lower ends of the valve body, and the valve body is divided into a pilot upper cavity, an atmospheric cavity, and a pilot cavity from top to bottom. The conical valve core is disposed inside the pilot cavity.

[0007] The inlet and outlet of the pilot upper cavity are respectively equipped with solenoid valves, and the atmospheric cavity is connected to the atmosphere; the conical valve core includes a valve plug and a valve seat, the valve plug has a conical structure, the bottom of the valve plug is connected to the valve body through a pilot lower spring, and the top of the valve plug is connected to the lower diaphragm, and a pilot upper spring is provided between the upper diaphragm and the lower diaphragm.

[0008] To better realize the present invention, the upper end of the pilot chamber is further connected to the outlet of the main pressure reducing valve through a pipe, and the lower end of the pilot chamber is connected to the upper chamber of the main pressure reducing valve through a pipe.

[0009] To better realize the present invention, the equivalent diameter ratio of the upper diaphragm and the lower diaphragm is further defined as follows:

[0010]

[0011] Where: Du is the equivalent diameter of the upper diaphragm;

[0012] Dd is the equivalent diameter of the lower diaphragm;

[0013] This is the area ratio coefficient between the upper and lower membrane sheets.

[0014] To better realize the present invention, the relationship between the top diameter and the bottom diameter of the valve plug is further defined as follows:

[0015] ;

[0016] The flow area of ​​the conical valve core is:

[0017] ;

[0018] in: The cone angle of the valve plug in the cone valve core;

[0019] This refers to the stroke of the valve plug in the conical valve core.

[0020] The cone height of the valve plug in the conical valve core;

[0021] L1 is the bottom diameter of the valve plug of the conical valve core;

[0022] L2 is the top diameter of the valve plug of the conical valve core.

[0023] An optimized design method for a micro-powered pilot valve with a conical valve core, used to optimize the design of the aforementioned micro-powered pilot valve with a conical valve core, characterized by comprising the following steps:

[0024] Step S1: Calculate the inlet and outlet flow velocities of the pilot upper cavity based on Bernoulli's equation and Darcy-Weisbach's formula. Then, based on the inlet and outlet flow velocities, obtain the minimum inlet and outlet volume VT of the pilot upper cavity, and further calculate the minimum actuation stroke lT of the upper diaphragm as follows:

[0025] ;

[0026] Where: Su is the equivalent area of ​​the upper membrane;

[0027] Step S2: Based on minimum inlet and outlet water volume Minimum travel of the upper diaphragm The minimum flow area of ​​the conical valve core is determined, and based on the mechanical balance relationship between the pressure in the upper chamber of the main pressure reducing valve and the conical valve core, constraints on the minimum opening of the pilot valve are constructed to ensure that the pilot valve meets the regulation requirements under extreme operating conditions; the constraints are as follows:

[0028] ;

[0029] in: This refers to the upper chamber pressure generated by the pilot valve under the minimum flow area.

[0030] The pressure in the upper chamber of the main pressure reducing valve;

[0031] This is the pressure redundancy coefficient;

[0032] Step S3: Based on the fact that the equivalent flow area of ​​the pilot valve's maximum stroke is equal to the flow area of ​​the pilot valve pipeline, the maximum stroke of the pilot valve is obtained.

[0033] To better realize the present invention, further, in step S1, the inlet and outlet water flow rates of the pilot upper cavity are:

[0034] ;

[0035] in: The pressure before the main pressure reducing valve;

[0036] Standard atmospheric pressure;

[0037] This refers to the inner diameter of the pipe.

[0038] This is the frictional resistance coefficient along the friction path;

[0039] The length of the pipe;

[0040] The fluid density is (kg / m³).

[0041] The minimum inlet and outlet water volume VT of the pilot upper cavity is:

[0042] ;

[0043] in: This is the minimum operating cycle time of the solenoid valve.

[0044] To better realize the present invention, further, in step S1, the equivalent area Su of the upper diaphragm is:

[0045] ;

[0046] Where: Du is the equivalent diameter of the upper diaphragm.

[0047] To better realize the present invention, further, in step S2, the minimum flow area of ​​the conical valve core is... for:

[0048] ;

[0049] in: The cone angle of the valve plug in the cone valve core;

[0050] The cone height of the valve plug in the conical valve core;

[0051] This refers to the stroke of the valve plug in the conical valve core.

[0052] L1 is the bottom diameter of the valve plug of the conical valve core;

[0053] L2 is the top diameter of the valve plug of the conical valve core.

[0054] To better realize the present invention, further, in step S2, constructing the constraint conditions includes the following steps:

[0055] (1) Based on the actual working conditions and the minimum design pressure after the valve, the low-peak flow rate QL of the main pressure reducing valve is estimated by Bernoulli's equation and West-Weisbach's formula;

[0056] ;

[0057] in: The design pressure of the main pressure reducing valve;

[0058] The pressure after the main pressure reducing valve during its lowest point;

[0059] The peak flow rate of the main pressure reducing valve;

[0060] To determine the final outlet pressure of the downstream system;

[0061] (2) Calculate the minimum flow area AL of the main pressure reducing valve based on the low-peak flow rate QL of the main pressure reducing valve;

[0062] ;

[0063] in: The flow coefficient of the main pressure reducing valve;

[0064] (3) Calculate the spring deformation of the main pressure reducing valve based on the minimum flow area AL. Then calculate the pressure in the upper chamber of the main pressure reducing valve. ;

[0065] ;

[0066] ;

[0067] in: The spring deformation of the main pressure reducing valve;

[0068] The Hooke's constant of the spring in the main pressure reducing valve;

[0069] Dmian-u is the diaphragm diameter of the upper chamber of the main pressure reducing valve;

[0070] Dmian is the diameter of the valve core cylinder of the main pressure reducing valve.

[0071] (4) Calculate the upper chamber pressure generated by the pilot valve under the minimum flow area. ;

[0072] ;

[0073] in: : The pressure before the main pressure reducing valve;

[0074] Friction resistance coefficient along the pipe (related to pipe wall roughness);

[0075] The equivalent length of the pipe installed on the pilot cavity;

[0076] : The length of the pipe between the pilot chamber and the upper chamber of the main pressure reducing valve;

[0077] : The length of the pipe between the pilot chamber and the main pressure reducing valve chamber;

[0078] : The diameter of the equivalent pipeline;

[0079] : Flow coefficient of the pipe connected to the conical valve core;

[0080] : Flow coefficient of the conical valve core;

[0081] : Cross-sectional area of ​​the conical valve core inlet;

[0082] : Cross-sectional area of ​​the cone-shaped valve core outlet.

[0083] To better realize the present invention, further, in step S3: the maximum stroke Δhmax of the pilot valve is:

[0084] ;

[0085] Where: L2 is the top diameter of the valve plug of the conical valve core;

[0086] The cone height of the valve plug in the conical valve core;

[0087] The cone angle of the valve plug in the cone valve core;

[0088] It is the equivalent coefficient of the flow area for the maximum stroke.

[0089] To better realize the present invention, further, in step S3: the Hooke coefficient of the pilot spring... for:

[0090] ;

[0091] The total length of the pilot lower spring of the pilot valve for:

[0092] ;

[0093] in: The Hooke's constant for the pilot spring;

[0094] This is the initial compression of the spring;

[0095] The spring compression rate is denoted as .

[0096] The beneficial effects of this invention are as follows:

[0097] (1) The conical valve core of the present invention adopts a conical structure, which has a more refined flow area adjustment capability. It can quickly and accurately adjust the spring deformation based on the small changes in the pilot chamber pressure, so as to achieve precise control of the high flow output pressure of the main pressure reducing valve, and make the fluid form a more uniform and stable flow field when passing through the valve core. The atmospheric cavity designed in the present invention uses the power generated by the pressure difference between the pipeline and the atmosphere to control the volume of the sealing water, so as to achieve the self-adjustment of the spring deformation. It does not need to rely on power energy, which greatly reduces the restriction threshold of installation and maintenance costs.

[0098] (2) Adjustment resolution is one of the important indicators for evaluating the performance of pilot-operated pressure reducing valves. This invention optimizes the linearity of the flow area through a conical valve core, solving the problem of low pressure regulation resolution caused by the nonlinearity of the flow area of ​​traditional valve cores, and achieving higher resolution pressure regulation control. This invention achieves a significant improvement in adjustment resolution by integrating Bernoulli's equation and Darcy-Weisbach formula from fluid mechanics, as well as the geometric structure of mechanics and other multidisciplinary theories. This invention combines fluid pressure monitoring technology to calibrate parameters such as the valve's equivalent flow area and fluid viscosity coefficient, and estimates valve flow based on fluid modeling, providing precise adjustment functions and multi-dimensional data support, effectively contributing to the construction of smart water management. This invention achieves breakthroughs in reducing energy consumption, improving adjustment accuracy, and adapting to complex working conditions, and has good practicality.

[0099] (3) Based on three levels of theoretical modeling, engineering calculation and system adaptation, this invention deeply integrates fluid mechanics and mechanical geometric parameters. Through multi-physics coupling analysis, precise correlation between dynamic flow velocity and volume, and performance verification under extreme conditions, a scientific, systematic and intelligent solution is constructed. Specifically, through multi-physics coupling analysis and dynamic verification, it ensures that high-precision regulation can still be maintained under minimum pressure and extreme conditions.

[0100] (4) Traditional pilot-operated pressure reducing valve design methods often rely on empirical formulas or simplified models, making it difficult to take into account the complex relationship between fluid dynamics characteristics, mechanical geometric constraints and actual working conditions. This invention introduces Bernoulli's equation (describing the conservation of fluid energy) and Darcy-Weisbach's formula (for calculating pressure loss along the flow path) from fluid mechanics, combined with mechanical geometric parameters (such as the cone angle of the conical valve core, the length of the flow path, the stiffness of the diaphragm, etc.), to construct a complete theoretical chain from flow velocity calculation to minimum inlet and outlet water volume, minimum diaphragm stroke, flow area and main pressure reducing valve flow rate, thus realizing the scientific prediction and verification of valve performance;

[0101] Precise correlation between flow velocity and volume: This invention first calculates the flow velocity of the pilot cavity during drainage or water intake based on Bernoulli's equation and Darcy-Weisbach's formula. Flow velocity is the core parameter for determining the minimum inlet and outlet water volume, and precise control of volume directly determines the minimum stroke of the upper diaphragm. Through mathematical modeling, the theoretical derivation of fluid mechanics and the physical response of mechanical displacement are unified, avoiding the accumulation of errors caused by neglecting fluid resistance or energy conversion in traditional designs.

[0102] Dynamic Verification of Flow Area and Mechanical Balance: In the geometric design of the conical valve core, this invention derives the flow area of ​​the conical valve core (a function of the cone angle and displacement) by using the minimum inlet and outlet water volumes and the minimum diaphragm stroke. Combined with the pressure in the upper chamber of the main pressure reducing valve and the mechanical balance relationship of the valve core, it verifies whether the valve core meets regulation requirements under extreme conditions (such as low pressure or high dynamic load) based on constraints. This process not only solves the problem of low pressure regulation resolution caused by the nonlinearity of the flow area of ​​traditional valve cores, but also ensures a high degree of matching between the structural parameters (such as cone angle and surface roughness) of the conical valve core and its actual performance through theoretical closed-loop design (calculation → verification → optimization), achieving a paradigm shift from "experience-driven" to "science-driven."

[0103] (5) In engineering practice, this invention has achieved a breakthrough in overcoming the dependence on traditional mechanical regulation and external energy. Through dynamic calculation and self-driving technology, it has significantly improved the reliability and adaptability of the system.

[0104] Self-powered energy utilization optimization: Traditional mechanical regulating pressure reducing valves rely on mains power or frequent manual operation of the pressure pin, resulting in installation limitations, high energy consumption, and decreased reliability. This invention creatively proposes using the power generated by the pressure difference between the pipeline and atmospheric pressure to control the volume of the sealing water, thereby driving the spring deformation for self-regulation. This design requires no external energy source, reducing reliance on complex power supply facilities and significantly improving safety and applicability in flammable and explosive environments or scenarios with inconvenient power supply, such as coal mine hydraulic support systems and industrial automation. Through theoretical calculations (such as analyzing the pressure difference energy conversion efficiency using Bernoulli's equation), this invention can accurately determine the minimum power requirement, ensuring stable regulation even with low energy consumption. This represents a major breakthrough in traditional energy-driven models.

[0105] Performance Verification under Extreme Conditions: This invention uses a theoretical model to quantitatively verify the performance of the conical valve core under extreme conditions. For example, under minimum pressure conditions, the flow requirement of the main pressure reducing valve is estimated using Bernoulli's equation and the Darcy-Weisbach formula. Combined with the minimum actuation stroke parameter, it is derived whether the flow area of ​​the conical valve core satisfies the mechanical equilibrium condition of the main pressure reducing valve. This process ensures the reliability of the design parameters in practical applications and avoids the performance deviation or failure risk caused by neglecting extreme conditions in traditional designs.

[0106] (6) This invention can not only serve the optimization of the physical performance of a single valve, but also provide a technical foundation for the intelligent management of complex systems through intelligent flow estimation and multi-dimensional data support;

[0107] The intelligent flow estimation system derives the flow area by analyzing the position and geometry of the conical valve core. Combined with the pressure difference across the main pressure reducing valve and fixed design parameters (such as valve seat diameter and flow path length), it estimates the flow rate in the main pressure reducing valve passage using Bernoulli's equation and the Darcy-Weisbach formula. Simultaneously, the flow rates in the main pressure reducing valve passage and the pilot passage are added to obtain the total valve flow rate. This intelligent flow estimation method, based on fluid mechanics and geometric parameters, achieves accurate quantification of total flow rate for the first time, providing data-driven decision-making capabilities for complex systems. This method also achieves real-time quantification of total flow rate for the first time (traditional valves often rely on empirical estimation), providing a theoretical basis for dynamic system adjustment and fault early warning.

[0108] Multi-dimensional data support: This invention integrates fluid pressure monitoring technology to calibrate key parameters such as the valve's equivalent flow area and fluid viscosity coefficient, constructing a complete data model. This data is not only used for real-time adjustment but also provides customers with precise adjustment functions and multi-dimensional data support (such as flow trend prediction and pressure fluctuation early warning), facilitating the digital upgrade of scenarios such as smart water management and industrial automation.

[0109] (7) This invention systematically solves the bottlenecks of traditional pilot-operated pressure reducing valves in terms of dynamic response, energy dependence, regulation accuracy, and flow management through multi-physics coupled modeling (fluid mechanics and mechanical geometry), self-driven energy innovation, dynamic pressure regulation strategy, and intelligent flow estimation system. Its advancement lies not only in the breakthrough of a single technical point, but also in the construction of a new design paradigm that highly integrates theoretical depth and engineering practice. It provides efficient, reliable, and highly adaptable solutions for scenarios such as industrial automation, coal mine hydraulic support systems, and smart water management, and has significant engineering value and industry promotion potential.

[0110] (8) This invention calculates the inlet and outlet water flow velocities of the pilot upper cavity using Bernoulli's equation and the West-Weisbach formula; determines the minimum inlet and outlet water volume (minimum injection or drainage volume) of the pilot upper cavity using the calculated flow velocities; and determines the minimum stroke (minimum displacement) of the upper diaphragm (actuator diaphragm) using the minimum inlet and outlet water volume. The flow rate of the main pressure reducing valve at minimum pressure is estimated using design parameters, Bernoulli's equation, and the West-Weisbach formula; the minimum flow area of ​​the conical valve core in extreme cases is determined using the flow rate and minimum displacement at the minimum pressure of the main pressure reducing valve, and the mechanical balance with the main pressure reducing valve is used to determine whether the design requirements are met; thereby determining whether the conical surface of the pilot valve core meets the requirements; and calculating the optimal stroke and the deformation and stroke of the valve core warning spring. This invention achieves the effects of optimized structural design, innovative power source, and improved regulation resolution.

[0111] (9) This invention calculates the flow velocity of the pilot upper cavity for drainage and water injection using Bernoulli's equation, West-Weisbach formula, and mechanical equilibrium; calculates the volume of the pilot upper cavity using the flow velocity of drainage and water injection and the opening time of the inlet and outlet solenoid valves; determines the position of the pilot valve core using the volume of the pilot upper cavity (intelligent pressure regulation requires leakage compensation); determines the flow area of ​​the valve core using the position and geometry of the pilot valve core; determines the pilot valve circuit flow rate and the pressure of the upper cavity of the main pressure reducing valve using the pilot valve flow area, the pressure before and after the valve, and fixed design parameters; determines the flow area of ​​the main pressure reducing valve using the pressure of the upper cavity of the main pressure reducing valve and the valve core parameters of the main pressure reducing valve; and determines the flow rate of the main pressure reducing valve passage using the flow area of ​​the main pressure reducing valve and the pressure difference before and after the main pressure reducing valve. The sum of the flow rates of the main pressure reducing valve passage and the pilot passage is the total valve flow rate. Attached Figure Description

[0112] Figure 1 This is a schematic diagram of the micro-powered pilot valve with a conical valve core according to the present invention.

[0113] Figure 2 This is a schematic diagram of the connection structure between the pilot valve and the main pressure reducing valve.

[0114] Figure 3 This is a schematic diagram showing the changes in the opening of the pilot valve.

[0115] Figure 4 This is a flowchart illustrating the design method of the micro-powered pilot valve with a conical valve core according to the present invention.

[0116] Wherein: 100-pilot valve, 101-valve body, 102-pilot upper cavity, 103-atmospheric cavity, 104-pilot cavity, 105-upper diaphragm, 106-lower diaphragm, 107-valve plug, 108-valve seat, 109-pilot upper spring, 110-pilot lower spring, 200-main pressure reducing valve, 201-main pressure reducing valve upper cavity, 202-main pressure reducing valve cavity, 203-pressure reducing valve core. Detailed Implementation

[0117] Example 1:

[0118] A micro-powered pilot valve with a conical valve core, such as Figure 1 and Figure 2As shown, the valve includes a conical valve core, a valve body 101, an upper diaphragm 105, and a lower diaphragm 106. The valve body 101 includes a pilot upper cavity 102, an atmospheric cavity 103, and a pilot cavity 104 arranged sequentially from top to bottom. The atmospheric cavity 103 is connected to the atmosphere. The conical valve core is disposed inside the pilot cavity 104. The upper diaphragm 105 and the lower diaphragm 106 are slidably disposed between the pilot upper cavity 102 and the atmospheric cavity 103, and between the atmospheric cavity 103 and the pilot cavity 104, respectively. A pilot upper spring 109 with a large Hooke's coefficient (approximately rigid) is disposed between the upper diaphragm 105 and the lower diaphragm 106. The conical valve core includes a valve seat 108 and a valve plug 107. The valve plug 107 has a conical structure. The top of the valve plug 107 is connected to the lower diaphragm 106, and a pilot lower spring 110 is provided between the bottom of the valve plug 107 and the pilot cavity 104.

[0119] Preferably, such as Figure 2 As shown, the main pressure reducing valve 200 includes an upper chamber 201, a body 202, and a pressure reducing valve core 203. The pressure reducing valve core 203 is housed within the body 202. A diaphragm is positioned between the upper chamber 201 and the body 202, and a spring is connected between the diaphragm and the upper chamber 201. The bottom of the diaphragm is connected to the valve plug 107 of the pressure reducing valve core 203. The upper and lower chambers of the pilot chamber 104 are connected to the upper chamber 201 and the outlet of the main pressure reducing valve, respectively, via pipes. The inlet of the main pressure reducing valve is connected to the upper chamber 201 and the upper pilot chamber 102, respectively, via pipes. Solenoid valves are installed at the inlet and outlet ends of the upper pilot chamber 102.

[0120] According to the principle of energy conservation and Bernoulli's equation in fluid mechanics, the pressure at the convergence point of the main pipe and the bypass in a fluid system is equal. The law of equal pressure difference in parallel pipe systems states that in a parallel pipe system (i.e., fluid flows from a main pipe to multiple branch pipes and eventually returns to the main pipe), the pressure difference (ΔP) between the inlet and outlet of each branch pipe is equal, and also equal to the pressure difference before and after the branching in the main pipe. Therefore, the following holds:

[0121] The pressure balance formula for the main pressure reducing valve 200 is:

[0122] (1);

[0123] in: Pressure loss in the main pressure reducing valve 200 circuit and the pilot valve 100 circuit;

[0124] : The pressure before the main pressure reducing valve 200;

[0125] : The pressure downstream of the main pressure reducing valve 200.

[0126] Pilot valve 100 pressure balance formula:

[0127] Setting: Since the cross-section of the upper pilot chamber 102 of the pilot valve 100 is much larger than the cross-section of the flow guide pipe of the pilot valve 100, the pressure loss of the upper chamber 201 of the main pressure reducing valve due to flow is ignored. ,

[0128] (2);

[0129] in: The dynamic pressure loss from the inlet of the main pressure reducing valve 200 to the upper chamber 201 of the main pressure reducing valve corresponds to the effective length of the pipeline. ;

[0130] The dynamic pressure loss from the upper chamber 201 of the main pressure reducing valve to the valve chamber of the pilot valve 100 corresponds to the effective length of the pipeline. ;

[0131] Dynamic pressure loss of the conical valve core;

[0132] The dynamic pressure loss from the pilot valve 100 valve chamber to the outlet of the main pressure reducing valve 200 corresponds to the effective pipeline length of: ;

[0133] The equivalent pipeline pressure loss caused by the combined pressure loss of the upper chamber 201 and the pilot chamber 104 of the main pressure reducing valve is 0 by default.

[0134] Example 2:

[0135] An optimized design method for a micro-powered pilot valve with a conical valve core, the design of which includes the following steps:

[0136] Step 1: Determine the pipe diameter using standard components;

[0137] Step 2: Based on Bernoulli's equation and the West-Weisbach formula, determine the minimum inlet and outlet water volumes generated by the solenoid valve of the pilot upper cavity 102 at the design pressure. Specifically, calculate the volume of water discharged based on the minimum operating cycle time of the solenoid valve (the limit time of switching), and determine the minimum operating stroke of the affected upper diaphragm 105.

[0138] First, the flow velocity in the pilot upper chamber 102 is calculated when the solenoid valve has the minimum operating cycle time, and then the minimum inlet and outlet water volume VT of the pilot upper chamber 102 is calculated.

[0139] (3);

[0140] in: The inner diameter of the pipe;

[0141] : Fluid flow velocity in the pilot upper cavity 102;

[0142] The minimum operating cycle time of the solenoid valve (the limit time for switching).

[0143] Preferably, the derivation process of the flow velocity is as follows:

[0144] Calculate the flow velocity of drainage or inflow in the upper cavity 102 of the pilot chamber: For incompressible fluids (such as liquids), when elevation changes are ignored, Bernoulli's equation simplifies to:

[0145] (4);

[0146] in: , These are the flow velocities before and inside the pipe, respectively. If the pipe diameter remains constant, then... ;

[0147] : Gravitational acceleration;

[0148] The pressure before the main pressure reducing valve 200, i.e. ;

[0149] Standard atmosphere;

[0150] Fluid density;

[0151] Pressure loss along the friction (Pa), calculated using the Darcy-Weisbach formula:

[0152] (5);

[0153] Friction resistance coefficient along the pipe, which is related to the Reynolds number Re and the pipe wall roughness;

[0154] : Length of the pipe (m);

[0155] : Inner diameter of the pipe (m);

[0156] Fluid velocity (m / s) Furthermore, by combining formulas (4) and (5), the calculation formula is obtained as follows:

[0157] (6);

[0158] If water continues to flow in, the flow rate will decrease as the flow continues.

[0159] Example 1: Assume the flow velocity (design maximum pressure) is If the pipe diameter is 6mm and the minimum operating cycle time of the solenoid valve is 0.05s, then substituting into formula (3) yields:

[0160] .

[0161] Example 2: Flow rate (actual operating condition) is If the pipe diameter is 6mm and the minimum operating cycle time of the solenoid valve is 0.05s, then substituting into formula (3) yields:

[0162] .

[0163] Example 3: The pressure before the valve is 1000 kPa (design maximum pressure), the atmospheric pressure is 101.3 kPa, the pipe diameter is 6 mm, the equivalent length of the pipeline (including equivalent bends, joints, solenoid valve body, etc.) is 20 m, the density of water is 1000 kg / m3, and the equivalent friction coefficient is 0.5 (including equivalent bends, joints, solenoid valve body, etc.); Substitute these values ​​into formula (6) to calculate the flow velocity:

[0164] ;

[0165] Example 4: The pressure before the valve is 450 kPa (actual working pressure), atmospheric pressure is 101.3 kPa, pipe diameter is 6 mm, equivalent pipe length (including equivalent bends, joints, solenoid valve body, etc.) is 20 m, water density is 1000 kg / m3, and equivalent (including equivalent bends, joints, solenoid valve body, etc.) friction coefficient is 0.5; substitute these values ​​into formula (6) to calculate the flow velocity:

[0166] Step 3: Determine the minimum actuation stroke of the upper diaphragm 105 of the pilot valve 100 by using the minimum inlet and outlet water volumes. ;

[0167] (7);

[0168] in: : The equivalent area of ​​the upper membrane 105.

[0169] Example: If the minimum inlet / outlet water volume of the pilot upper cavity 102 is The effective diameter of the upper diaphragm 105 is 74 mm. Substituting this into formula (7), the minimum stroke (i.e., resolution) of the upper diaphragm 105 is:

[0170] .

[0171] Example: If the minimum inlet / outlet water volume of the pilot upper cavity 102 is The effective diameter of the upper diaphragm 105 is 74 mm. Substituting this into formula (7), the minimum stroke (i.e., resolution) of the upper diaphragm 105 is:

[0172] .

[0173] Step 4: Under the minimum operating stroke lT of the upper diaphragm 105, the minimum flow area ΔSmin is obtained as follows:

[0174] (8);

[0175] The derivation of formula (8) can be found in Example 3.

[0176] The bottom diameter L2 of the valve plug 107 is usually the same as the diameter of the pipeline; the relationship between the top diameter L2 and the bottom diameter L1 of the valve plug 107 is as follows:

[0177] (9).

[0178] Step 5: Introduce actual operating conditions and establish an actual operating condition model. Calculate the low-peak flow rate of the main pressure reducing valve 200 based on the minimum design pressure downstream of the valve. Assume: 1. The downstream environment is not an open environment, but rather pipelines, equipment, etc., all of which have flow resistance; 2. The characteristics of the downstream system can be simplified to a resistance equation; 3. Water is an incompressible liquid, and the flow velocity is equal at all points with a constant pipe diameter. .

[0179] For water flowing through the main pressure reducing valve 200, the basic relationship of its volumetric flow rate Q follows the following standard formula:

[0180] (10);

[0181] in:

[0182] The pressure before the main pressure reducing valve 200, i.e. ;

[0183] The downstream pressure of the main pressure reducing valve 200, i.e. ;

[0184] Fluid density;

[0185] : The flow area of ​​the valve core of the main pressure reducing valve 200;

[0186] : The flow coefficient of the main pressure reducing valve 200 (dimensionless, usually determined by experiments; for water valves, an initial estimate of 0.65~0.75 can be taken).

[0187] The relationship between pipeline pressure loss and flow rate / velocity is a core component of fluid mechanics and engineering calculations, and can be specifically divided into two categories: friction loss and local pressure loss. Based on formula (5) and Q=S×v=(πD² / 4)×v, the Darcy-Weisbach formula is obtained as follows:

[0188] (11);

[0189] in:

[0190] Pressure loss along the friction path (Pa);

[0191] Friction drag coefficient along the pipe (related to Reynolds number Re and pipe wall roughness);

[0192] Pipe length (m);

[0193] Pipeline flow rate;

[0194] : Inner diameter of the pipe (m);

[0195] Fluid density (kg / m³);

[0196] : Fluid velocity (m / s);

[0197] S: Pipe cross-sectional area.

[0198] Simplifying it, we get:

[0199] (12);

[0200] make: Then the operating condition of the downstream end of the main pressure reducing valve 200 can be simplified as follows:

[0201] (13);

[0202] in: The total resistance coefficient of the downstream system (unit: Pa / (m³ / s)²) can be obtained by calculating the sum of the pipe friction loss and local losses, or by experimental calculation.

[0203] : Determine the final outlet pressure (atmospheric pressure) of the downstream system.

[0204] Based on formula (13), calculate the off-peak flow rate of the main pressure reducing valve 200:

[0205] (14);

[0206] in: The design pressure of the main pressure reducing valve 200;

[0207] The pressure downstream of the main pressure reducing valve 200 during its lowest period;

[0208] The peak flow rate of the main pressure reducing valve 200;

[0209] The low-peak flow rate of the main pressure reducing valve 200.

[0210] For example, the design pressure of the main pressure reducing valve 200 is 1 MPa, the peak flow rate is 0.35 m³ / s, and the downstream pressure during the off-peak period needs to reach 0.15 MPa. Substituting this into formula (14), the off-peak flow rate is obtained as follows: .

[0211] Step 6: Based on the mechanical balance of the main pressure reducing valve 200 under actual working conditions, set the constraint conditions for the pilot valve 100.

[0212] Based on formula (10), and taking into account the low-peak flow rate QL of the main pressure reducing valve 200, the minimum flow area AL of the main pressure reducing valve 200 is calculated as follows:

[0213] (15);

[0214] Spring deformation of main pressure reducing valve 200 for:

[0215] (16);

[0216] The pressure in the upper chamber 201 of the main pressure reducing valve is... for:

[0217] (17);

[0218] (18);

[0219] The pressure generated by the pressure on the diaphragm inside the main pressure reducing valve 200 is achieved by the spring force transmitted to the diaphragm from above. (Upward), and the pressure in the upper chamber 201 of the main pressure reducing valve. (Downward), the pressure below is influenced by the low-pressure downstream of the main pressure reducing valve 200. (Upward), and the pressure difference between the water pressure and the pressure of the pressure reducing valve core 203 is transmitted to the diaphragm. (Upward); Based on the equilibrium equation, we get formula (17), where the left end is the downward pressure on the diaphragm and the right end is the upward pressure on the diaphragm.

[0220] in: The spring deformation of the main pressure reducing valve 200;

[0221] The Hooke's constant of the spring in the main pressure reducing valve 200;

[0222] Dmian-u is the diaphragm diameter of the upper chamber 201 of the main pressure reducing valve;

[0223] Dmian is the diameter of the valve core cylinder of the main pressure reducing valve 200.

[0224] ΔP12 is the difference between the upstream pressure P11 and the downstream pressure P13 of the main pressure reducing valve 200.

[0225] The pressure after the main pressure reducing valve 200 during its lowest period.

[0226] Calculate the upper chamber pressure generated by pilot valve 100 under minimum flow area. : (19);

[0227] The specific derivation of formula (19) can be found in Example 3, which is based on formula (54), formula (57) and formula (58).

[0228] If the valve core angle is a parameter of When the cone height is h1, the minimum operating cycle time of the solenoid valve is... Pipe diameter L2 is At this time, the minimum opening degree of the pilot valve 100 needs to meet the following requirements:

[0229] (20).

[0230] Example 1: If the traffic flow during off-peak hours for The flow coefficient of the main pressure reducing valve 200 during off-peak hours If the value is 0.65, then substituting it into formula (15), the minimum flow area of ​​the main pressure reducing valve 200 is obtained as follows:

[0231] ;

[0232] If the diameter Dmian of the valve core cylinder of the main pressure reducing valve 200 is 300mm and the minimum flow area of ​​the main pressure reducing valve 200 is 0.0127 square meters, then substituting into formula (16), the required spring deformation of the main pressure reducing valve 200 is:

[0233] ;

[0234] If the diaphragm diameter Dmian-u of the upper chamber 201 of the main pressure reducing valve is 640mm, the Hooke coefficient of the spring of the main pressure reducing valve 200 is... Given a spring deformation of 0.0135m required for the main pressure reducing valve 200 (1000 N / mm), substituting this into formula (17), the required pressure for the upper chamber 201 of the main pressure reducing valve is:

[0235] .

[0236] Example 2: The design pressure of the main pressure reducing valve 200 is 1 MPa, the peak flow rate is 0.35 m³ / s, and the downstream pressure needs to reach 0.15 MPa during off-peak periods. The pipeline diameter L2 = 6.5 mm. The pilot valve 100 is designed with the following parameters: Cone height If the minimum flow area of ​​the conical valve core is The equivalent length of the pilot valve pipeline (m) is 100. It is 2mm. , The lengths are 0.2m and 0.8m respectively. The pressure before the main pressure reducing valve 200 is 1 MPa, and the pressure after the main pressure reducing valve 200 is 0.15 MPa. The flow coefficient of the pilot valve 100 in the small pipeline is... If the pilot valve 100 has a pipeline diameter of 0.65, the valve core flow coefficient is: 0.75, friction coefficient of pilot valve 100a : 0.02; then substitute into formula (19) to obtain the upper cavity pressure generated by the minimum flow area of ​​the pilot valve 100. Then, substitute into formula (20) to determine whether the constraint conditions are met. Step 7: Design the maximum stroke of the conical valve core through the equivalent flow area;

[0237] Basic theory: The equivalent flow area of ​​the pilot valve 100 at its maximum stroke is greater than the equivalent flow area of ​​the pilot valve 100 pipeline; that is:

[0238] (twenty one);

[0239] (twenty two);

[0240] The derivation of formula (22) is shown in Example 3; here it is the condition for the pilot valve stroke when the flow area of ​​the conical valve core is greater than or equal to the pilot valve inlet area in the second stage.

[0241] : Equivalent coefficient of flow area at maximum stroke default ;

[0242] Pilot loop pipe diameter, ; ;

[0243] Based on formulas (21) and (22), we obtain:

[0244] (twenty three);

[0245] Simplified, we get:

[0246] (twenty four);

[0247] The limit requirement is:

[0248] (25).

[0249] Example: If the cone height h1=2.2; the cone angle α=π / 6; the flow area equivalent coefficient K2s=1.8; and the pipe diameter L2=6.5; then substitute into formula (25) to obtain the design stroke of the pilot valve 100.

[0250] Preferably, it also includes the design of the upper diaphragm 105 and the pilot upper spring 109;

[0251] The top of the upper diaphragm 105 is subjected to pressure from the upper pilot cavity 102, and the bottom of the upper diaphragm 105 transmits pressure through the upper pilot spring 109 in the air cavity; the force generated by the lower diaphragm 106 is obtained by combining the force generated by the pilot cavity 104 and the atmosphere and the force generated by the compression deformation of the lower pilot spring 110. To ensure the power of the pilot valve 100, the model is simplified: other influences (such as gravity, friction, etc.) are ignored, and it is assumed that... ,in:

[0252] : The equivalent area of ​​the upper membrane 105;

[0253] The area ratio coefficient between the upper membrane 105 and the lower membrane 106;

[0254] The equivalent area of ​​the lower diaphragm along its axis is 106; therefore, the following condition is met:

[0255] (26);

[0256] Right now:

[0257] (27);

[0258] Simplified, we get:

[0259] (28);

[0260] The equivalent area of ​​the upper membrane 105 is:

[0261] ;

[0262] Where: Du is the equivalent diameter of the upper diaphragm 105.

[0263] Therefore, the effective diameter ratio of the upper diaphragm 105 and the lower diaphragm 106 is:

[0264] (29);

[0265] The deformation of the pilot spring 109 satisfies:

[0266] (30);

[0267] (31).

[0268] Example: If the lower diaphragm 106 is a standard diaphragm with an outer diameter of 80 mm and an outer diameter (the part that can effectively withstand pressure) of 54 mm, then substituting into formula (29), the outer diameter of the upper diaphragm 105 is obtained as follows:

[0269] ;

[0270] The outer diameter of the upper diaphragm 105 is 76 + (80 - 54) = 102 mm.

[0271] Preferably, it also includes the design of the pilot lower spring 110;

[0272] Initial spring compression (deformation): The valve is in the fully closed state (all points are under static pressure, and the pressure after the valve is 0, i.e.): If so, the pressure generated by the pilot valve 100 cannot push it open:

[0273] (32);

[0274] (33);

[0275] (34);

[0276] in: : Hooke's constant of the pilot spring 110;

[0277] : Initial compression (deformation) of the spring;

[0278] The area of ​​the top of valve plug 107.

[0279] The valve is in a slightly open state (each point is in a micro-flow state, the opening of the conical valve core is less than the minimum solenoid valve action time, and the downstream pressure is the minimum design pressure, i.e.: If the pilot valve 100 is in a slightly open state, then the pressure generated by the pilot valve 100 is in this state. The minimum slightly open deformation is:

[0280] (33);

[0281] Simplified to:

[0282] (34);

[0283] Establish the balance of the pilot spring 110:

[0284] (35);

[0285] in: The valve design requires the valve core stroke (opening) at the minimum regulating pressure (pressure).

[0286] The differential pressure achieved by the conical valve core under minimum pressure conditions;

[0287] (36);

[0288] The flow area through the pilot valve 100 is:

[0289] (37).

[0290] In the pilot valve 100 system, to ensure the stiffness of the upper spring (default micro-rigid body), the Hooke coefficients of both the upper and lower springs are selected as follows:

[0291] (38);

[0292] Since the spring has a limiting compressibility, the total length of the spring is:

[0293] (39);

[0294] (40);

[0295] in: : Total length of the pilot valve spring 100;

[0296] : Spring compression rate.

[0297] Example: Since springs are standard parts, they are usually made in 5mm increments, therefore the following must be met:

[0298] ;

[0299] in: : Positive integer;

[0300] : Natural numbers.

[0301] Example 3:

[0302] This embodiment is an optimization based on Embodiment 2. The derivation of the flow area ΔS is as follows:

[0303] like Figure 3 As shown, the area of ​​the standard cone surface is:

[0304] ;

[0305] in: : Radius of the base of the cone;

[0306] : Length of side busbar.

[0307] Phase 1: As Figure 3 As shown in (a) above, the flow area at this time The area of ​​the frustum obtained by drawing a perpendicular line between the valve core and the guide cone surface (the area of ​​the larger cone S1 is reduced by the area of ​​the smaller cone S2);

[0308] Where A'B'C'D' is the position where ABCD is shifted down by Δh, and a perpendicular line is drawn from point A' to the side of AC, with the foot of the perpendicular at R and the intersection point with the central axis at O; then there exists:

[0309] A'B'=L2, A'N=L2 / 2, AA'=Δh, A'N=L2 / 2, ∠ACD=∠RON=α, NO=h1;

[0310] NO = (L1 / 2) × cotα;

[0311] A'R = Δh × cosα;

[0312] A'O = L2 / (2sinα)

[0313] Based on r2=A'O, calculate S2=πr2×r2×sinα=π(L2 / (2sinα))2×sinα;

[0314] Based on r1=RO=A'O+A'R, calculate S1=πr1×r1×sinα=π(Δh×cosα+L2 / (2sinα))2×sinα;

[0315] Based on the above formula, we can obtain:

[0316] (8);

[0317] Phase Two: As Figure 3 As shown in (b) above, the flow area at this time This refers to the area of ​​the frustum formed between the upper edge of the valve core and the lower edge of the guide cone surface. (The area of ​​the larger cone S1 is reduced by the area of ​​the smaller cone S2).

[0318] ;

[0319] ;

[0320] Among them, such as Figure 3 As shown in (b), the transformation relationship is obtained by using the proportional relationship between the hypotenuse and base of similar triangles (△CEA' and △COM):

[0321] ,Right now .

[0322] The basic formula based on the lateral surface area of ​​a cone ,get:

[0323] .

[0324] Similarly, by using the proportional relationship between the hypotenuse and base of similar triangles (△CEA' and △A'ON), we can obtain:

[0325] ;

[0326] ;

[0327] ;

[0328] In the third stage, such as Figure 3 As shown in (c), assuming the minimum flow area equals the inlet area, then based on the formula for the lateral surface area of ​​a frustum, we obtain:

[0329] (twenty two);

[0330] like Figure 3 As shown in (b), in the second stage, when a perpendicular line is drawn from point A' to AC, with the foot of the perpendicular at point C, then:

[0331] ;

[0332] like Figure 3 As shown in (c), the third stage occurs when the flow area of ​​the second stage equals the valve core inlet area. At this point:

[0333] ;

[0334] Simplifying, we get:

[0335] ;

[0336] Therefore, in the second stage:

[0337] .

[0338] In summary, the cone area S1 of the guide is:

[0339] (41);

[0340] The area S2 formed by the valve core and the conical surface is: (42);

[0341] The flow area ΔS of the conical valve core is:

[0342] (43);

[0343] (9);

[0344] in: for Figure 3 The cone surface area of ​​the cone formed by the virtual radius r1 shown;

[0345] for Figure 3 The area of ​​the cone surface formed by the virtual radius r2 shown;

[0346] The cone angle of the valve plug 107 of the cone valve core;

[0347] L1 is the bottom diameter of the valve plug 107 of the conical valve core;

[0348] L2 is the top diameter of the valve plug 107 of the conical valve core.

[0349] The cone height of the valve plug 107 of the conical valve core;

[0350] The stroke of the valve plug 107 of the conical valve core.

[0351] Preferably, in order to better apply it to actual engineering projects, and taking into account multiple factors, the above-mentioned approach based on the second and third stages... The formula for equality introduces the equivalent coefficient of the flow area for the maximum stroke. The stroke Δh of the pilot valve in the second stage is derived and simplified to:

[0352] (25).

[0353] Based on formula (25), the maximum stroke Δhmax of the pilot valve in step S3 is obtained as follows:

[0354] .

[0355] Preferably, the relationship between the pressure in the upper chamber 201 of the main pressure reducing valve and the flow area of ​​the pilot valve 100 is derived as follows (i.e., the derivation process of formula (19)):

[0356] Based on formulas (2) and (11), the equivalent pipeline pressure loss of the combined pressure loss of the upper chamber 201 and pilot chamber 104 of the main pressure reducing valve is calculated. It is calculable under extreme conditions (Darcy-Weisbach modified formula):

[0357] (44);

[0358] get:

[0359] (45);

[0360] in: Equivalent pipe length;

[0361] The flow rate of the equivalent pipeline is the same at all points in the branch.

[0362] : The diameter of the equivalent pipeline;

[0363] Width of the main pressure reducing valve 200;

[0364] The equivalent diameter of the main pressure reducing valve 200. ;

[0365] Friction resistance coefficient along the pipe (related to pipe wall roughness);

[0366] : Design volume of the upper chamber 201 of the main pressure reducing valve (ignoring the volume difference caused by deformation);

[0367] For example, if the equivalent pipeline inner diameter is 6mm, the upper cavity design volume is 22.1L, and the main pressure reducing valve 200 has a designed effective modulus length of 220mm, then the equivalent pipeline length of the upper cavity 201 of the main pressure reducing valve is:

[0368] ;

[0369] For example, if the equivalent pipeline inner diameter is 6mm, the pilot valve 100 has a design volume of 0.41L, and the main pressure reducing valve 200 has a design effective length of 20mm, then the equivalent pipeline length of the upper cavity is:

[0370] ;

[0371] Based on formula (2), ignore ,make: Based on formula (11), substitute into the Darcy-Weisbach formula: (46);

[0372] in:

[0373] : Pressure loss along the pipe installed on the pilot cavity 104 (Pa);

[0374] : Equivalent length (m) of the pipe installed on the pilot cavity 104. ;

[0375] : The flow velocity of the pipe installed on the pilot cavity 104;

[0376] Fluid density (kg / m³).

[0377] Among them, the dynamic pressure loss of the conical valve core The derivation is as follows:

[0378] Bernoulli's equation is a fundamental equation in fluid mechanics describing the energy conservation relationship along streamlines for an ideal fluid under steady flow conditions. Its general form is as follows:

[0379] set up:

[0380] 1. The fluid is an ideal fluid (viscous and incompressible);

[0381] 2. Under dynamic equilibrium, the flow is steady (i.e., the velocity, pressure, etc. at each point do not change with time).

[0382] 3. The mass force is only gravity (or there is a potential external force).

[0383] 4. Established along the same streamline.

[0384] "Hydraulic and Pneumatic Transmission Control Technology" 2.3.3 Bernoulli's equation is:

[0385] (47);

[0386] in: : is the velocity of the fluid;

[0387] It is gravitational acceleration;

[0388] : is the height relative to a certain reference point (usually in the vertical direction);

[0389] It is pressure;

[0390] : is fluid density;

[0391] : is a constant along the same streamline;

[0392] : Differential symbol; Head form: Based on formula (47), divide each term by gravitational acceleration The energy per unit weight of fluid can be obtained; converted into:

[0393] (48);

[0394] in: Total head (constant along streamlines);

[0395] Based on formula (48), substituting the valve core:

[0396] (49);

[0397] in: : is the velocity of the inlet fluid;

[0398] : is the height of the entrance relative to a reference point (usually in the vertical direction);

[0399] : is the inlet pressure;

[0400] : is the velocity of the inlet fluid;

[0401] : is the height of the entrance relative to a reference point (usually in the vertical direction);

[0402] : is the inlet pressure;

[0403] If the pilot valve is installed horizontally, then In other methods, the elevation difference can be ignored. (Actual engineering requires horizontal installation); Based on formula (49), it can be simplified to:

[0404] (50);

[0405] Compared to formula (4) above, the pressure loss along the friction path is ignored here because the friction path is shorter. .

[0406] in: : Pressure difference of the valve core;

[0407] Substitute the relationship between flow rate and flow velocity:

[0408] (51);

[0409] in: : Cross-sectional area of ​​valve core inlet;

[0410] : Cross-sectional area of ​​valve core outlet;

[0411] Pipeline flow rate;

[0412] Note: In some theories, the velocity before the valve is neglected. :Right now However, it cannot be ignored in this project;

[0413] In practical engineering, the viscosity coefficient affects the pressure loss caused by viscosity and friction during the flow of actual fluids. ;

[0414] (52);

[0415] in: The flow coefficient for small pipelines is obtained through laboratory calibration or by referring to a table.

[0416] The valve core flow coefficient varies with the Reynolds number and is obtained through laboratory calibration or by referring to a table.

[0417] Based on the above formulas (46) and (52), the equilibrium state is as follows:

[0418] (53);

[0419] in: The flow coefficient of the conical valve core varies with the Reynolds number and can be obtained by laboratory calibration or by referring to a table.

[0420] The flow coefficient of the conical valve core connecting pipe varies with the Reynolds number and can be obtained by laboratory calibration or by referring to a table.

[0421] The inlet cross-sectional area of ​​the conical valve core is equivalent to the flow area of ​​a small pipe. ;

[0422] The cross-sectional area of ​​the conical valve core outlet is obtained by the pilot valve's 100-degree stroke.

[0423] ;

[0424] Therefore, the relationship between the equivalent pipeline flow rate and the valve core flow area is as follows:

[0425] (54);

[0426] Based on formula (52), the dynamic pressure loss of the conical valve core is... for:

[0427] ;

[0428] In the circuit containing the pilot valve:

[0429] ;

[0430] Then, formula (54) is derived.

[0431] in: Pressure loss in the main pressure reducing valve 200 circuit and the pilot valve 100 circuit;

[0432] : Pressure loss along the pipe installed on the pilot cavity 104 (Pa);

[0433] Based on formulas (11), (53), and the above The formula is used to obtain the pressure in the upper cavity of the pilot valve 100. The relationship with pilot valve 100 is as follows: (55);

[0434] Based on formulas (54) and (55), substitute into have to:

[0435] (56).

[0436] Secondly, the relationship between the upper chamber pressure (industry-standard pressure) and the flow area of ​​the pilot valve spool is as follows: (57);

[0437] Based on formula (54), substitute into ,get:

[0438] (58);

[0439] Wherein, ΔP12 equals P11-P2-L; and thus formula (19) is derived.

[0440] in: The dynamic pressure loss from the upper chamber 201 of the main pressure reducing valve to the valve chamber of the pilot valve 100 corresponds to the effective length of the pipeline. ;

[0441] Dynamic pressure loss of the conical valve core;

[0442] The dynamic pressure loss from the pilot valve 100 valve chamber to the outlet of the main pressure reducing valve 200 corresponds to the effective pipeline length of: .

[0443] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A micro-powered pilot valve with a conical valve core, characterized in that, The valve body includes a valve body, an upper diaphragm, a lower diaphragm, and a conical valve core. The upper and lower diaphragms are slidably arranged at the upper and lower ends of the valve body, and the valve body is divided into a pilot upper cavity, an atmospheric cavity, and a pilot cavity from top to bottom. The conical valve core is arranged inside the pilot cavity. The inlet and outlet of the pilot upper cavity are respectively equipped with solenoid valves, and the atmospheric cavity is connected to the atmosphere; the conical valve core includes a valve plug and a valve seat, the valve plug has a conical structure, the bottom of the valve plug is connected to the valve body through a pilot lower spring, and the top of the valve plug is connected to the lower diaphragm, and a pilot upper spring is provided between the upper diaphragm and the lower diaphragm.

2. A micro-powered pilot valve with a conical valve core according to claim 1, characterized in that, The upper end of the pilot chamber is connected to the outlet of the main pressure reducing valve via a pipe, and the lower end of the pilot chamber is connected to the upper chamber of the main pressure reducing valve via a pipe.

3. A micro-powered pilot valve with a conical valve core according to claim 1, characterized in that, The equivalent diameter ratio of the upper and lower diaphragms is: ； Where: Du is the equivalent diameter of the upper diaphragm; Dd is the equivalent diameter of the lower diaphragm; This is the area ratio coefficient between the upper and lower membrane sheets.

4. A micro-powered pilot valve with a conical valve core according to claim 1, characterized in that, The relationship between the top diameter and the bottom diameter of the valve plug is as follows: ； The flow area of ​​the conical valve core is: ； in: The cone angle of the valve plug in the cone valve core; This refers to the stroke of the valve plug in the conical valve core. The cone height of the valve plug in the conical valve core; L1 is the bottom diameter of the valve plug of the conical valve core; L2 is the top diameter of the valve plug of the conical valve core.

5. An optimization design method for a micro-powered pilot valve with a conical valve core, used to optimize the design of a micro-powered pilot valve with a conical valve core as described in any one of claims 1-4, characterized in that, Includes the following steps: Step S1: Calculate the inlet and outlet flow velocities of the pilot upper cavity based on Bernoulli's equation and Darcy-Weisbach's formula. Then, based on the inlet and outlet flow velocities, obtain the minimum inlet and outlet volume VT of the pilot upper cavity, and further calculate the minimum actuation stroke lT of the upper diaphragm as follows: ； Where: Su is the equivalent area of ​​the upper membrane; Step S2: Based on the minimum inlet and outlet water volume VT and the minimum operating stroke of the upper diaphragm The minimum flow area of ​​the conical valve core is determined, and based on the mechanical balance relationship between the pressure in the upper chamber of the main pressure reducing valve and the conical valve core, constraints on the minimum opening of the pilot valve are constructed to ensure that the pilot valve meets the regulation requirements under extreme operating conditions; the constraints are as follows: ； in: This refers to the upper chamber pressure generated by the pilot valve under the minimum flow area. The pressure in the upper chamber of the main pressure reducing valve; This is the pressure redundancy coefficient; Step S3: Based on the fact that the equivalent flow area of ​​the pilot valve's maximum stroke is equal to the flow area of ​​the pilot valve pipeline, the maximum stroke of the pilot valve is obtained.

6. The optimized design method for a micro-powered pilot valve with a conical valve core according to claim 5, characterized in that, In step S1, the inlet and outlet water flow velocities of the pilot upper cavity are: ； in: The pressure before the main pressure reducing valve; Standard atmospheric pressure; This refers to the inner diameter of the pipe. This is the frictional resistance coefficient along the friction path; The length of the pipe; The fluid density is (kg / m³). The minimum inlet and outlet water volume VT of the pilot upper cavity is: ； in: This is the minimum operating cycle time of the solenoid valve.

7. An optimized design method for a micro-powered pilot valve with a conical valve core according to claim 5 or 6, characterized in that, In step S1, the equivalent area Su of the upper diaphragm is: ； Where: Du is the equivalent diameter of the upper diaphragm.

8. The optimized design method of a micro-powered pilot valve with a conical valve core according to claim 5, characterized in that, In step S2, the minimum flow area of ​​the conical valve core for: ； in: The cone angle of the valve plug in the cone valve core; The cone height of the valve plug in the conical valve core; This refers to the stroke of the valve plug in the conical valve core. L2 is the top diameter of the valve plug of the conical valve core.

9. The optimized design method of a micro-powered pilot valve with a conical valve core according to claim 8, characterized in that, In step S2, constructing the constraints includes the following steps: (1) Based on the actual working conditions and the minimum design pressure after the valve, the low-peak flow rate QL of the main pressure reducing valve is estimated by Bernoulli's equation and West-Weisbach's formula; ； in: The design pressure of the main pressure reducing valve; The pressure after the main pressure reducing valve during its lowest point; The peak flow rate of the main pressure reducing valve; To determine the final outlet pressure of the downstream system; (2) Calculate the minimum flow area AL of the main pressure reducing valve based on the low-peak flow rate QL of the main pressure reducing valve; ； in: The flow coefficient of the main pressure reducing valve; (3) Calculate the spring deformation of the main pressure reducing valve based on the minimum flow area AL. Then calculate the pressure in the upper chamber of the main pressure reducing valve. ; ； ； in: The spring deformation of the main pressure reducing valve; The Hooke's constant of the spring in the main pressure reducing valve; Dmian-u is the diaphragm diameter of the upper chamber of the main pressure reducing valve; Dmian is the diameter of the valve core cylinder of the main pressure reducing valve. (4) Calculate the upper chamber pressure generated by the pilot valve under the minimum flow area. ; ； in: : The pressure before the main pressure reducing valve; Friction resistance coefficient along the pipe (related to pipe wall roughness); The equivalent length of the pipe installed on the pilot cavity; : The length of the pipe between the pilot chamber and the upper chamber of the main pressure reducing valve; : The length of the pipe between the pilot chamber and the main pressure reducing valve chamber; : The diameter of the equivalent pipeline; : Flow coefficient of the pipe connected to the conical valve core; : Flow coefficient of the conical valve core; : Cross-sectional area of ​​the conical valve core inlet; : Cross-sectional area of ​​the cone-shaped valve core outlet.

10. The optimized design method of a micro-powered pilot valve with a conical valve core according to claim 5, characterized in that, In step S3: the maximum stroke Δhmax of the pilot valve is: ； Where: L2 is the top diameter of the valve plug of the conical valve core; The cone height of the valve plug in the conical valve core; The cone angle of the valve plug in the cone valve core; It is the equivalent coefficient of the flow area for the maximum stroke.

11. The optimized design method of a micro-powered pilot valve with a conical valve core according to claim 5, characterized in that, In step S3: the Hooke coefficient of the pilot spring for: ； The total length of the pilot lower spring of the pilot valve for: ； in: The Hooke's constant for the pilot spring; This is the initial compression of the spring; The spring compression rate is given.

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