Abstract
By analyzing the working principle of the wedge gate valve with large diameters, an optimal design scheme for the structure of the wedge gate valve with large diameters is proposed. Design the size of the corresponding parts, and optimize the calculated size according to the use requirements; select the materials of each part reasonably. The results show that the design meets the requirement for strength.
Background
A gate valve with a large diameter has a diameter of 350 to 1 200 mm and is widely used in industrial pipelines and water supply pipelines. The valve body is the main part of the gate valve, and its parameters and structure type have a certain influence on the overall performance. Because the valve body of the gate valve with large diameters is limited by the length of the structure and the inner cavity of the gate valve is an elliptical or oblate container, so theoretical formulas cannot be used to analyze the strength and optimize the structure based on engineering experience. In the process of continuous development of information technology, advanced design methods are used for engineering technology in the process of the traditional product's development and design. The optimal design of the wedge gate valve with a large diameter is analyzed.
1. The structure of the wedge gate valve with large diameters
The wedge gate valve with large diameters adopts the principle of threaded screw drive to transmit force to the plate through an electric mechanism or a hand wheel, making the wedge plate rise or fall to open or close the valve. When the gate valve is opened, the drive motor turns on the power; the valve stem is used to drive the valve to move upward at a certain speed, generally at a speed of 10mm/s. Set a predetermined height for the valve plate. After it reaches the height, the power drive of the electric mechanism will stop. At this time, the valve plate is fully opened and the medium flows smoothly. For wedge gate valves with large diameters, the flow can be adjusted. The flow of the flowing medium can be adjusted according to the height of the valve plate. When the valve plate is closed, it will be lowered to the lowest point, and the groove under the valve plate will be deformed, which has a good sealing effect. The main modes of the wedge gate valve with large diameters designed in this article include opening and closing. The function of the valve body is medium transmission when it is opened, making it a part of the pipeline. The valve body is required to have sufficient strength because of the resistance of the conveying pipeline to the force of the medium and the tensile stress when it is closed. The valve body is the main component, which is especially important when the valve is opened or closed. The valve body will be subjected to the pressure of the flow medium when it is closed, and the outflow section of the medium doesn't bear force, resulting in the pressure difference between the inlet and outlet and the deformation of the valve body. In engineering, the requirements for the strength and rigidity of the valve body are relatively high, which makes the valve have good sealing and reliability.
2. Structural optimization of wedge gate valves with large diameters
2.1 Influencing parameters of the strength of valve bodies
The ribs on both sides of the valve body are positions with the maximum stress, so the size of the outer ribs and the shape of the cavity will affect the strength of the valve body. The structural parameters of the middle cavity section and outer reinforcing rib are considered and optimized in this article.
2.2 Optimization of the section parameters of the valve seat's boss
In order to avoid the problem of stress concentration in the valve body, to make the stress evenly distributed, and to meet the requirement for strength, it is necessary to optimize the cavity's structure. The main goal of this optimization is that the maximum value of the equivalent stress of the valve body is smaller than the allowable stress of the material. The results show that the valve cavity has the maximum stress, which affects the shape parameters of the middle valve cavity. The main parameters include R, R1 and L1, so the design variables are defined as DS_R, DS_R1 and DS_L. The initial values are 1300 mm, 40 mm and 112. 5 mm.
Because of practical engineering problems, the actual requirements for the project must be met in the variable selection and design process, so the constraint conditions are designed as follows: DS_R being 900 to 1500 mm, DS_R1 30 to 70 mm, and DS_L 101 to 124 mm.
Use the first-order optimization method to optimize. Set the penalty function in the objective function. Transform the constrained multivariable nonlinear programming problem to unconstrained; automatically optimize the program, and divide the model network in the optimization. After optimization analysis, optimized results can be obtained. The corresponding results are obtained after the finite element optimization analysis of the interface size of the valve seat's boss. DS_L has an effect on the equivalent stress of the valve body, which means that when the short axis length L is 109 mm, the maximum equivalent stress is the smallest. When it deviates from this value, the stress can rise rapidly, and this distribution law also exists in the response diagram of other parameters.
By analyzing the working principle of the wedge gate valve with large diameters, an optimal design scheme for the structure of the wedge gate valve with large diameters is proposed. Design the size of the corresponding parts, and optimize the calculated size according to the use requirements; select the materials of each part reasonably. The results show that the design meets the requirement for strength.
Background
A gate valve with a large diameter has a diameter of 350 to 1 200 mm and is widely used in industrial pipelines and water supply pipelines. The valve body is the main part of the gate valve, and its parameters and structure type have a certain influence on the overall performance. Because the valve body of the gate valve with large diameters is limited by the length of the structure and the inner cavity of the gate valve is an elliptical or oblate container, so theoretical formulas cannot be used to analyze the strength and optimize the structure based on engineering experience. In the process of continuous development of information technology, advanced design methods are used for engineering technology in the process of the traditional product's development and design. The optimal design of the wedge gate valve with a large diameter is analyzed.
1. The structure of the wedge gate valve with large diameters
The wedge gate valve with large diameters adopts the principle of threaded screw drive to transmit force to the plate through an electric mechanism or a hand wheel, making the wedge plate rise or fall to open or close the valve. When the gate valve is opened, the drive motor turns on the power; the valve stem is used to drive the valve to move upward at a certain speed, generally at a speed of 10mm/s. Set a predetermined height for the valve plate. After it reaches the height, the power drive of the electric mechanism will stop. At this time, the valve plate is fully opened and the medium flows smoothly. For wedge gate valves with large diameters, the flow can be adjusted. The flow of the flowing medium can be adjusted according to the height of the valve plate. When the valve plate is closed, it will be lowered to the lowest point, and the groove under the valve plate will be deformed, which has a good sealing effect. The main modes of the wedge gate valve with large diameters designed in this article include opening and closing. The function of the valve body is medium transmission when it is opened, making it a part of the pipeline. The valve body is required to have sufficient strength because of the resistance of the conveying pipeline to the force of the medium and the tensile stress when it is closed. The valve body is the main component, which is especially important when the valve is opened or closed. The valve body will be subjected to the pressure of the flow medium when it is closed, and the outflow section of the medium doesn't bear force, resulting in the pressure difference between the inlet and outlet and the deformation of the valve body. In engineering, the requirements for the strength and rigidity of the valve body are relatively high, which makes the valve have good sealing and reliability.
2. Structural optimization of wedge gate valves with large diameters
2.1 Influencing parameters of the strength of valve bodies
The ribs on both sides of the valve body are positions with the maximum stress, so the size of the outer ribs and the shape of the cavity will affect the strength of the valve body. The structural parameters of the middle cavity section and outer reinforcing rib are considered and optimized in this article.
2.2 Optimization of the section parameters of the valve seat's boss
In order to avoid the problem of stress concentration in the valve body, to make the stress evenly distributed, and to meet the requirement for strength, it is necessary to optimize the cavity's structure. The main goal of this optimization is that the maximum value of the equivalent stress of the valve body is smaller than the allowable stress of the material. The results show that the valve cavity has the maximum stress, which affects the shape parameters of the middle valve cavity. The main parameters include R, R1 and L1, so the design variables are defined as DS_R, DS_R1 and DS_L. The initial values are 1300 mm, 40 mm and 112. 5 mm.
Because of practical engineering problems, the actual requirements for the project must be met in the variable selection and design process, so the constraint conditions are designed as follows: DS_R being 900 to 1500 mm, DS_R1 30 to 70 mm, and DS_L 101 to 124 mm.
Use the first-order optimization method to optimize. Set the penalty function in the objective function. Transform the constrained multivariable nonlinear programming problem to unconstrained; automatically optimize the program, and divide the model network in the optimization. After optimization analysis, optimized results can be obtained. The corresponding results are obtained after the finite element optimization analysis of the interface size of the valve seat's boss. DS_L has an effect on the equivalent stress of the valve body, which means that when the short axis length L is 109 mm, the maximum equivalent stress is the smallest. When it deviates from this value, the stress can rise rapidly, and this distribution law also exists in the response diagram of other parameters.
Next: The Optimal Structural Design of the Large Wedge Gate Valve (Part Two)
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