Regulating valve technical problem solving

Our some customer for regulating valve products in use process, a series of questions caused our engineers to make the following solutions, suggest another customer before selection please consulting engineers, or the personnel of the service. Because selection is more important than calculation, calculation and selection of comparison, selection is much more important and more complex. Because computing is just a simple formula, its itself is not the accuracy of the formula, but in a given by process parameters are accurate. Selection involves the content is more, a little careless, will lead to improper selection, not only a waste of manpower, financial and material resources, and use effect is not ideal, so bring some use problems, such as feasibility, reliability and quality of life, running, etc. A, regulating valve which several main functions are there? 1, regulating flow, pressure, adjust temperature, cut off the medium, the shunt confluence, etc. Second, why is regulating valve in use process produce oscillation? 1, the regulating valve spring stiffness is insufficient, regulating valve output signal is not stable and rapid changes in easy cause oscillation regulating valve. 2, and the selected valve at the same frequency and system frequency or pipe and a violent vibration, the regulating valve vibration. 3, improper selection of regulating valve working in a small open degree there is a sharp change of flow resistance, flow velocity, pressure, when more than the stiffness of the valve, poor stability, serious when produce oscillation. 4, due to the causes of oscillation are various, specific analysis to specific issue. 3 why cannot be used as cut off valve, double sealing valve? 1, two-seater valve valve core has the advantage of force balance structure, allow the pressure difference is big, but its disadvantage is that the two seal face not good contact at the same time, cause leakage. 2, if it is artificially, forcibly used to cut off the occasion, obviously the result is bad, even as it made many improvements ( Such as double sealing sleeve valve) It is not desirable. Four criteria for the installation, regulating valve is what? 1, first of all to adjust valve installation shall be in accordance with the regulations of the design drawings and design documents strictly implement and performance of all inspection before installation. 2, want to consider the valve to the work environment adaptability, and the installation of the regulating valve, must ensure the safety, ensure the use of performance, easy operation and maintenance. Five, the regulating valve plugging problems often appear card? 1, regulating valve, plug often appear at the beginning of the new operation system and overhaul of commissioning, due to the pipe welding slag, rust and other body parts in the throttle opening and guide jam making medium circulation. 2, regulating valve repair in sealed tight, causing friction increases, lead to small signal action, the phenomenon of large signal action too. Six, why quarter-turn valves to cut off the pressure difference is bigger? 1, quarter-turn valves to cut off the pressure difference is bigger, because the media on the valve core and valve plate produced by the resultant force on the rotating shaft torque is very small, so it can bear large pressure difference. Seven, why easy oscillation when small two-seater valve opening work? 1, for single core, when the medium is away, the valve has good stability; When the medium is flow closed type, poor stability of the valve. Two-seat valves have two valve core, the valve core flow closed, valve core in the flow, so, when you are working in a small open degree, the flow of the closed type valve core is easy to cause the vibration of the valve, this is the reason why two-seat valves cannot be used for small open degree work. Eight, cut off valve: why do you want to choose hard seal? 1, cut off valve leakage, the lower the better, soft sealing valve leakage is the lowest, to cut off the effect of course good, but not wear-resisting, poor reliability. From small leakage and sealing and reliable double standards, soft seal cutting is not as good as hard seal cut off. If the seal with a hard seal cut off valve, its reliable performance, leakage rate 10 ~ 7, have been able to meet the requirements of cut off valve. Nine, general positioning device mainly exist the following fault type 1, due to adopt mechanical force balance principle of work, the more moving parts, are susceptible to the influence of temperature, vibration, due to the volatility of the regulating valve. 2, the nozzle baffle technology, as a result of nozzle hole is very small, vulnerable to dust or dirty air plug, make the positioning device can't work normally. 3, using force balance principle, the elastic coefficient of spring in bad change, caused by nonlinear led to the decrease of the quality of the control valve adjustment. Ten: welcome and look forward to your participation and technical difficulties, or if you have any more questions, you are welcome to call the valve door counseling and communication, because of your participation, we will become stronger, more professional.