Abstract: A new type of mesh valve with self-elastic buffer sheet compressor is presented. The center of this valve buffer sheet has no elastic arm and is designed as an elastic body. Therefore, the working process of the buffer sheet has small stress, large self-rigidity coefficient, Sheet spring force, valve reliability. The finite element method is used to calculate the stiffness coefficient, work process stress and equivalent mass of self-projectile, and the corresponding mathematical model of valve working process is established. Mesh valve with self-elastic buffer sheet compressor mesh valve used in a series of large! Medium-sized compressor valve design or modification, the effect is good. Keywords: compressor; mesh valve; self-elastic buffer piece; reliability; mathematical model; application 0 Introduction The valve is one of the most important and most vulnerable parts of reciprocating compressors [1]. Mesh valve is commonly used in large and medium-sized reciprocating compressor valve. The traditional non-friction belt buffer sheet mesh valve buffer sheet by the center of the fixed part of the elastic arm, buffer sheet in the spring force under the elastic deformation is mainly the deformation of the elastic arm. This buffer piece of flexible arm work stress, and its own smaller coefficient of rigidity. In many occasions, the need for the buffer itself has a high stiffness coefficient, which can use a larger buffer spring force to increase the buffering effect, but at the same time buffer stress during the work can not be too large, so as not to cause the buffer piece reliability Decline, this time, the traditional buffer elastic arm is difficult to design [2]. To this end, this paper presents a self-elastic buffer sheet mesh valve compressor [3]. 1 with self-populating buffer compressor mesh valve structure with self-populating buffer compressor mesh valve structure shown in Figure 1, which from top to bottom seat, valve, lift pads, self-elastic buffer sheet and Lifting limiter. Lifting limiter spring hole, which by the outer side of the slightly smaller spring hole is equipped with a pressure on the buffer piece of the spring, called the buffer spring; by the inner slightly larger spring hole is equipped with a pressure on the valve spring, said The valve spring. Unlike the traditional non-friction belt mesh type valve, the mesh type valve with self-elastic buffer sheet compressor is characterized in that the buffer sheet has no elastic arm on the fixed center of the buffer sheet, and the buffer sheet itself is designed as an elastic body, thus the buffer sheet Since the bomb buffer film. Since the elastic buffer piece ring connected by the tendons, the elastic deformation under the spring force of the buffer piece mainly refers to the deformation of the connecting bars. Since the bomb buffer film in addition to the outermost ring, the ring inside the straight slot broken. In this way, on the one hand the valve plate spring can be pressed through these grooves against the valve plate and on the other hand the rigidity of the damping plate itself can be reduced. 2 self-elastic buffer piece calculation Figure 1 shows the mesh valve self-projectile buffer top view in Figure 2, since the buffer center of the buffer plate close to the site for the fixed part of the gasket, the outermost outer ring for the free end, A ~ H in Figure 2 at the buffer with a spring piece. Obviously, under the action of the spring force of the buffer sheet, the buffer sheet has the deformation and the stress. The maximum deflection of the buffer sheet is at the outermost circumference of the outer ring, and the maximum tensile stress is at the joint between the root of the connecting rib and the center fixing ring. Because of the complex shape of the buffer sheet, the finite element method is used to calculate the deformation and stress during the working process of the buffer sheet. The elastic coefficient Ks of self-elastic buffer sheet is the formula, Fs is the total spring force that presses on the buffer sheet; Wmax is the maximum deflection of self-elastic buffer sheet. Since the deflection of each ring of self-elastic buffer sheet is not the same, when using single point mathematical model to analyze the movement rule of valve, the motion quality of buffer sheet needs to adopt equivalent motion quality [4]. Since the buffer piece equivalent to the quality of movement can be obtained by Rayleigh law. Taking the static flexural surface of self-elastic buffer plate as the vibration shape [5], the equivalent mass Med of self-projectile buffer plate is calculated by finite element method, where Ï is the density of self- Average deflection of a unit; Vi is the volume of the ith unit. For self-elastic buffer sheet shown in Figure 1, the outermost outer diameter of 332mm, rib width of 16mm, the outer diameter of the centering ring is 74mm lift gasket outer diameter of 52mm, the outermost ring width of 13mm, the middle ring Width of 10mm, ring and ring groove width of 5mm, the thickness of the buffer piece 2mm, the diameter of the center of the buffer piece spring is 312mm The width of each ring when the slit width of 30mm, finite element analysis by ANSYS software [6], get The stiffness coefficient of the self-elastic buffer sheet is 3214 kN / m, and the equivalent exercise mass is 01318 kg. When the maximum deflection of the buffer piece is 1mm, the maximum tensile stress of the buffer piece is 4416MPa. Compared with the traditional friction-free mesh valve buffer sheet with elastic arms, the rigidity coefficient of the self-elastic buffer sheet is much larger, so it can withstand the larger spring force of the buffer sheet, the buffering effect is good, the amplitude of the tilting movement of the valve is small ; When the maximum deflection is the same, the maximum stress of self-elastic buffer sheet is much smaller, so it has good reliability [2]. The stiffness coefficient of self-elastic buffer sheet is easily adjusted according to requirements, such as changing the thickness of self-elastic buffer sheet, the number, width and length of connecting ribs. 3 mathematic model of working process of mesh valve with self-absorbing buffer compressor The mathematical model of working process of mesh valve with self-absorbing buffer plate compressor includes valve's equation of motion, energy conservation equation, continuity equation and corresponding boundary conditions And the initial conditions. Take the cover side suction valve as an example to establish the mathematical model of the working process of the mesh valve with self-acting buffer sheet compressor. Valve during the opening process, before colliding with the buffer sheet, or in the process of closing, and the buffer sheet after the separation, the equation of motion is where Mv is the equivalent weight of the valve disc and leaf spring; ω is Crankshaft rotation angular velocity; h is the valve disc displacement; γ is the crank angle; Ap is the effective bearing area; β is the thrust coefficient relative to Ap [4]; ps is the gas pressure in the suction chamber; p is the gas pressure in the cylinder; Fv is the sum of the elastic force generated by the elastic arm and the leaf spring [4]. When the valve plate and the buffer fit, together with the movement, the equation of motion is: where Md is the sum of the equivalent mass of motion of the self-projectile and the buffer; Fd is the sum of the self-projectile and the buffer spring The sum of elasticity. When the compressed gas can be simplified to ideal gas flow through the suction valve can be simplified into one-dimensional, stable, adiabatic flow, you can get the following energy conservation equation, K is the isentropic index; V is the cylinder working volume [1 ]; Ms is the specific volume of gas in the suction; m is the mass of gas flowing through the suction valve. The gas mass flowing through the suction valve is obtained from the continuity equation, where N is the number of valves on the same side of the same name; Aef is the effective flow area of ​​the valve [4]; R is the gas constant; Ts is the gas in the suction chamber temperature. Cover side of the suction valve working process energy loss W1, where γ0 is the valve opening angle [1]; Vh is the cylinder stroke volume; λ is the crank radius connecting rod length ratio. In the working process of the mesh valve with self-elastic buffer compressor, there is a collision between the valve plate and the valve seat and the lift limiter. The speed relationship before and after the collision is in the formula, CR is the rebound coefficient, which is taken as 0125 [4]. During the valve opening process, there is also a collision with the self-projectile buffer. When the collision between the valve plate and the self-projectile buffer is regarded as a completely inelastic collision [4], the following boundary conditions are available: Numerical calculations using smaller steps , Hi \ H1 when, where, H1 is the valve lift minus the static state of self-elastic buffer under the action of the spring force under the maximum deflection. In the mathematical model of the working process of a mesh valve with a self-acting snubber compressor, the initial conditions are the same as those of the ring valve [1]. At this time, the crank angle is the opening angle, and the corresponding gas pressure in the cylinder is controlled by the gas force of the valve plate and the valve The relationship between the spring force is equal, the valve displacement, velocity, the gas flow through the valve, the valve loss of energy are zero. The above mathematical model is solved by fourth-order Runge-Kutta method [1], which can get the movement law, the flow capacity and the energy loss of the valve. One of the laws of movement of the valve economy and reliability of a great influence. In order to verify the above mathematical model, this article uses a self-projectile buffer compressor mesh valve on the LW-22/8 oil-free air compressor. Measured a cover side of the suction valve movement law and simulation of the valve movement in Figure 3. As can be seen from Fig. 3, the law of motion of the gas valve simulated by the above mathematical model can basically reflect the actual movement law of the gas valve. Good valve movement law requires the valve to open in time, close in time and have a longer period of full open, while the valve moving parts collision speed, high reliability. The analysis of the movement rule of the mesh valve with self-elastic buffer sheet compressor obviously shows that the existence of self-elastic buffer sheet and buffer sheet spring can effectively reduce the collision speed between the valve sheet and the lift limiter. Compared with the traditional friction-free belt mesh valve, the mesh valve with self-absorbing buffer plate compressor can properly increase the rigidity coefficient of the self-elastic buffer plate and the spring force of the buffer plate, correspondingly slightly reduce the spring force of the valve plate, It is conducive to the timely opening of the valve, closing in time, but also help to reduce the valve and lift limiters, the seat of the collision speed. Through the optimization of the mesh valve with self-elastic bumper compressor [4], the maximum static deflection of self-elastic bumper under spring force is about 40% of the lift. 4 with self-populating buffer compressor mesh valve applications Self-populating buffer compressor mesh valve has been used in a series of large and medium-sized compressor valve design or transformation, the effect is good. The following to H22â…¢-165/320 nitrogen and hydrogen compressor valve transformation as an example. H22â…¢-165/320 Nitrogen Hydrogen Compressor is a four-row symmetrical balanced compressor with an annual output of 20,000 tons of synthetic ammonia. It is the main type of nitrogen-hydrogen compressor in medium-sized ammonia plant, accounting for medium-sized ammonia plant nitrogen and hydrogen 1/3 of the total number of compressors. According to statistics, the average compressor of the first stage of the average valve life of about one month, second to fourth-class valve average life of about two months. After using the mesh valve with self-elastic buffer compressor to transform, the average service life of the first-stage valve exceeds 4 months, and the average service life of the 2nd-4th valve exceeds 6 months. The first to the fourth level of the valve from the bomb buffer after a long period of operation, there is no fracture. Mesh valve with self-elastic buffer compressor has been in the country more than 20 major H22III-165/320 nitrogen and hydrogen compressor to run business promotion [7]. Through a large number of applications of mesh valve with self-absorbing buffer compressor, the application effect analysis shows that the mesh valve with self-absorbing buffer compressor has high reliability. References: [1] Lin Mei, Yu Yongzhang. Valve components. See: Yu Yongzhang editor. Volume compressor technical manual. Beijing: Mechanical Industry Press, 2000 [2] Pan Shulin, Lu Zhaoxia, Zhang Zengying, etc. Compressor Compressor technology, 2002 (5): 43 ~ 45 [3] Pan Shulin, Xie Lianhua, Yang Lin. A compressor valve. Chinese utility model patents, ZL98217013.0, 1999 [4] Pan Shulin. Reciprocating compressor mesh valve working characteristics: [Ph. D. Thesis]. Xi'an: Xi'an Jiaotong University, 1996 [5] Ni Zhenhua. Vibration Mechanics. Xi'an: Xi'an Jiaotong University Press, 1989 [6] Tan Jianguo. Finite element analysis using ANSYS6.0. Beijing: Peking University Press, 2002 [7] Pan Shulin, Lu Zhaoxia, Zhang Zengying, etc .. Research and application of H22 nitrogen and hydrogen compressor high efficiency valve. Journal of Guangxi University, 2002 , 27 (4): 284 ~ 287 (edit Guo Wei) About the author: Pan Shulin, male, born in 1970. Xiangtan University, Associate Professor of Mechanical Engineering, Ph.D. Research direction for the compressor work process. Published 22 papers. Gong Shuguang, male, born in 1964. Xiangtan University, Associate Professor of Mechanical Engineering. Lu, female, born in 1969. Guangxi University School of Chemistry and Technology lecturer. Wolfson, male, born in 1947. Wenzhou City, Zhejiang Europe Valve Manufacturing Co., Ltd. General Manager, economist.
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