barbed wire,Barebed Wire,Stainless Steel Wire Hogs Fence,Iron Wire Barbed Wire anping yaqi wire mesh co.,ltd , https://www.apyaqiwiremesh.com
Flow coefficient in the valve during the use of important parameters
Valve flow coefficient and cavitation coefficient is an important valve parameters, which are generally available in the advanced industrial countries, the valve material, even in the sample also printed. China's production of the valve is basically no information in this area, because access to this information need to do experiments can be made, this is our country and the world's advanced level of the valve one of the important performance gap. Valve flow coefficient Valve flow coefficient is a measure of valve flow capacity index, the greater the value of the flow coefficient, the smaller the pressure loss when the fluid flows through the valve. According to KV value calculation formula: KV-flow coefficient Q-volume flow m3 / h ΔP-valve pressure loss bar P-fluid density kg / m3 valve cavitation coefficient Cavitation coefficient δ value, to select the control flow, the choice of what type of valve structure. Where: H1 - after the valve outlet pressure m? H2 - atmospheric pressure and its temperature corresponding to the difference between the saturated vapor pressure m? ΔP - before and after the valve pressure difference m? Due to the different structures of various valves, therefore, allowed cavitation coefficient δ Also different. as the picture shows. If the calculated cavitation coefficient is greater than the allowable cavitation coefficient, then it is available and no cavitation will occur. If the butterfly valve allows a cavitation coefficient of 2.5, then: • If δ> 2.5, cavitation does not occur. When 2.5> δ> 1.5, slight cavitation can occur. When δ <1.5, vibration occurs. δ <0.5 continued to use the case, it will damage the valve and downstream piping. The basic characteristics of the valve and operating characteristics of the valve, the valve cavitation occurs at a time when it is out of sight, not to mention that at that point to reach the operating limit. Through the above calculation is clear at a glance. So cavitation, because the liquid flow through the process of accelerating a tapered cross-section, some of the liquid gasification, the bubble then generated after the valve open section of the burst, the performance of three:? 1 noise? 2 can cause severe vibration Damage to the foundation and related structures, resulting in fatigue fracture? 3 on the material damage to the valve body and pipeline erosion? Again from the above calculation, it is not difficult to see the cavitation and valve pressure H1 have a great relationship, increase H1 apparently To change the situation, to improve the method:? A. The valve installed in the pipeline lower point. b. Install the orifice plate on the pipe behind the valve to increase the resistance. c. Valve outlet is open, direct reservoir, so that the bubble burst space increases, reduced cavitation. ? Comprehensive analysis of the above four aspects, discussion, summed up the gate valve, butterfly valve main features and parameter list easy to use. Two important parameters in the valve operation.