V-notch Ball Valve Disc Structure And Equal Percentage Flow Characteristic Analysis

Since the1970s, the V-notch ball valve was invented abroad, it has a wide rage of usesin the medium fluid systems which is containing fiber of industrial production because of itsfluid resistance small, the flowing capability big, the switch rapid, the good tightness, thelong life of use and the high adjustable ratio. It was introduced into China since the80’s,there have been only a few manufacturers in the country having the capable of producing theV-notch ball valve, and the design method of the V-notch ball valve is mainly based on theexperimental parameter, but there are still key technologies not to solve, and the regulationperformance is still low, It is difficult for products to achieve the ideal percentage flowcharacteristics.The basic structure of the V-notch ball valve was analyzed, the structure parameterssuch as the chord length of the valve core spherical crown league round bottom, radius ofthe spherical crown, the height between the centre of rotation and round bottom, the size andposition of the V openings etc. The relations between the circulation area and flow indifferent openings were deduced, at the same time proposing requirements of parameteroptimization.The flow characteristic analysis of the V-notch ball valve is mainly discussing the flowarea analysis, different circulation area have different flow resistance, so the flow coefficientis not the same. Want to make the flow characteristics reach to the ideal percentage flowcharacteristics, we must change the circulation area in different openings, and make flowcoefficient be close to the coefficient of the ideal percentage flow characteristics, and thenimprove its flow characteristics. According to the structural mechanism and relationship ofthe V-notch ball valve, the three-dimensional model of the rotation disc was established,adjusting the all parameters of the disc, and make the flow coefficient in different openingscompliance with the regulations of the ideal percentage flow characteristics.This calculation method was tested in this paper. The flow coefficient which obtainedfrom the structure calculation of original disc is close to the test flow coefficient, and thecorrectness and feasibility of using this method that change the structure parameters of discand the optimized flow characteristics are proved. Calculating on this basis, develop thecorresponding optimization software, and using this optimization software can change thestructure parameters of valve disc easily and quickly until find the structure of the valve discsuit with the ideal percentage flow characteristics. Through the above research, improve the V-notch ball valve flow characteristicseffectively, the design V-notch ball valve flow characteristics consistent with equalpercentage flow characteristic, reduce the flow coefficient error. The flow area calculateformula, flow coefficient calculate method and optimization software of V-notch ball valveunder different degrees, for engineering design provides a fast and efficient calculationmethod, simplifies the design calculation process, optimization of the Disc structure,improve the regulate characteristics of V-notch ball valve.