Research On The High Pressure And Large Flow Relief Valve Design And Experimental System

High pressure and large flow relief valve is a key application infrastructure which controls the operation of hydraulic support. When the relief valve working, it discharges on time the high pressure emulsion inside the upright post which could easily harms equipment under the impact load, thus protecting the support. With the rapid growth on the high yield and high efficiency coal face, relief valve developing to high pressure and large flow is required as well as more reliability and longevity. Now the relief valve in China produced and designed mainly though survey or imitation of related products abroad, which lacks direction of design philosophy. Meanwhile, be short of synthetic test-bed of relief valve characterized with large flow, approximate working conditions and commonality not only seriously constrains the development of relief valve technology and quality, but also affects the standard implementation of the high pressure and large flow valve of hydraulic support.The core of the research of the relief valve technology is structure design and experimental installations. The high pressure and large flow relief valve used by hydraulic support is featured typically with high pressure when working, with large flow, with working conditions under sudden impact and using HFAM as working medium. Under the condition that those typical conditions mentioned above are satisfied, this thesis aims at the improvement of design capability and experiment measures of relief valve. Combined with theoretical analysis and experimental verification, the paper puts main indexes design, structure design and test-bed construction, etc. as key research problems. Related researches mainly own following five aspects:(1) Analysis has been made on the physical and chemical property of HFAE which is the working medium of high pressure and large flow relief valve. It has been compared and analyzed on the different structure forms(Directly Drive Type, Pilot Type and Differential Type), on the different elastic elements(Spring-loaded Type and Air-filled Type) and on the different seal forms for valve port(Cone Valve, Spool Valve and Ball Valve). On the basis, the influence of different type of relief valve structure to its performance is studied which lies foundation for the design of high pressure and large flow relief valve. Based on the rated flow and working pressure of the high pressure and large flow relief valve the paper intends to designe, valve core structure of directly drive type is adopted, drainage holes of track type is employed for the first time on the design of valve core structure, and the related mechanical analysis is made according to the working principle of relief valve, and the main technology indexes is initially confirmed.(2) Three-dimensional simulation analysis is carried out on the static pressure, dynamic pressure and speed, etc. of the relief valve flow distribution of four valve core structures with software Fluent. The influence of the valve core structure and the indexes to the the flow conditions inside the valve core of relief valve. Through comparative analysis, it is obtained that 1 with the same shape yet different area of oil discharging holes, the area of oil discharging holes directly relates to the changes of flow speed and pressure inside valve body, the minimum negative pressure and the speed of fluid in runner decreases with the increasing of the area of drainage holes; 2 that under the condition that the areas are the same, yet the shapes of the oil discharging holes are different, the liquidity inside the valve core of track type is better than that inside round type. With powerful discharging capacity and with the fluid inside valve runner under impact state featured with low flow liquidity and small negative pressure, it is certain that the comprehensive performances of Plan 4 valve core of track type is optimum.(3) Modeling and simulated analysis is conducted on the high pressure and large flow relief valve with machinery system dynamics software ADAMS and electric-hydraulic simulative software AMESim. By the construction of the shock mass-spring system for this valve, the shock conditions of relief valve under high impact pressure can be simulated. Through repeated modification, the quality spring system for relief valve characterized with fast response, small shock range and short steady time is gained. The dynamic performances of the valve core system of relief valve is improved as well as the reliability of valve.(4) The hydraulic system of synthetic test-bed of high pressure and large flow relief valve is designed. The key components of test-bed is designed and the model selected. Meanwhile the test system based on Lab VIEW is designed.(5) Four valve cores with different structure of relief valve are tested under impact experiment. It is arrived at the conclusion that the Plan 4 relief valve is optimum at flow discharging and steady through experiment which is consistent with simulated results. Meanwhile, through experiment on nominal flow cracking, spilling and closing, experiment on small flow cracking, spilling and closing and experiment on pressurization and low pressure seal which indicate that all the technological indexes of the Plan 4 relief valve totally satisfying the national standard GB25974.3-2010 with outstanding performance and fine stability.Put structure design as principle line, modern analysis instruments like CFD, ADAMS and AMESim systematic simulation used as supplementary means, this thesis states the analysis and design process of relief valve, develops the product of large flow relief valve and experimental system, brings about the reliable design and quality detection for relief valve, constructs the design theory and method for high pressure and large flow relief valve used by support, supports the design of high pressure and large flow relief valve with high performance technically.