The principle and characteristics of electric control valves
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2014-09-23
Electric control valve is an intelligent control valve that is powered by a power source and receives a unified standard electrical signal of 0-10mA (or 4-20mA). After being amplified by a servo amplifier, the electric motor drives the reducer to operate and generate axial thrust, thereby adjusting the valve core for corresponding displacement, and achieving variable regulation of process medium flow, pressure, temperature, liquid level, and other variables.
Electric control valves are composed of two parts: an electric actuator and a control valve, which are divided into two types: straight through single seat and straight through double seat. The latter has the characteristics of high flow capacity, low imbalance force, and stable operation, so it is usually particularly suitable for situations with high flow rate, high pressure drop, and low leakage.
The flow characteristic of an electric regulating valve is the relationship between the relative flow rate of the medium flowing through the regulating valve and its opening under the condition of maintaining a constant pressure difference at both ends of the valve. There are three types of flow characteristics of electric control valves: linear characteristics, equal percentage characteristics, and parabolic characteristics.
The meanings of the three flow characteristics are as follows: (1) Equal percentage characteristic (logarithmic) The relative stroke and relative flow rate of equal percentage characteristic are not linearly related, and the change in flow rate caused by unit stroke change at each point of stroke is proportional to the flow rate at that point, and the percentage change in flow rate is equal. So its advantage is that when the flow rate is small, the flow rate changes little. When the flow rate is large, the flow rate changes greatly, which means that it has the same adjustment accuracy at different opening angles.
(2) The relative stroke and relative flow rate of a linear characteristic are linearly related. The change in flow rate caused by a change in unit stroke remains unchanged. When the flow rate is high, the relative change in flow rate is small, while when the flow rate is low, the relative change in flow rate is large.
(3) The parabolic characteristic flow rate varies proportionally to the two sides of the stroke, and generally has intermediate characteristics of linear and equal percentage characteristics.
From the analysis of the above three characteristics, it can be seen that in terms of its regulation performance, the equal percentage characteristic is the better, with stable regulation and good regulation performance. The parabolic characteristic has better regulation performance than the linear characteristic, and any one of the flow characteristics can be selected according to the requirements of different usage scenarios. Beijing Xinmeidi Valve Control Valve Series Products: Pneumatic Control Valves: Pneumatic Diaphragm Single Seat Control Valves ZMZP, ZMAP, ZMBP, Pneumatic Diaphragm Double Seat Control Valves ZMAN, ZMBN. Pneumatic precision small film regulating valve ZJHP, pneumatic precision small film sleeve regulating valve ZJHM, pneumatic three-way diversion regulating valve ZAZQ, ZMAQ, pneumatic three-way merging regulating valve ZAZX, ZMAX, pneumatic light small regulating valve ZXMAP, ZXMAN, ZXMAM, pneumatic high-pressure angle regulating valve ZMAS, ZMBS, pneumatic regulating cut-off, O-type ball valve ZSHO, pneumatic piston regulating cut-off butterfly valve ZSCW, pneumatic V-type clamp ball valve ZSHV, pneumatic piston type quick cut-off valve ZSPQ Pneumatic diaphragm piston shut-off valve ZMQ, ZSQ, pneumatic fluorine lined regulating valve ZMPF, CV3000 series regulating valve HLS, HTS, HCB, HPS, HPC, HAA, HAC, HCP, HPN electric regulating valve: electric single seat regulating valve ZAZP, electric double seat regulating valve ZAZN, electric sleeve regulating valve ZAZM, intelligent regulating ball valve ZRQO, electronic electric regulating valve ZDLP, ZDLM, electronic electric double seat regulating valve ZDLN, electronic electric three way combined regulating valve ZDLQ, ZDLX Electric three-way shunt regulating valve ZAZQ, electric three-way combined regulating valve ZAZX, electric V-type regulating valve ZKJV, electronic V-type regulating valve ZDJV, electric precision small single seat regulating valve ZAJP, electric precision small sleeve regulating valve ZAJM, precision small electronic regulating valve ZDHP, ZDHM, electric regulating butterfly valve ZAJM Self operated regulating valve: self operated pressure regulating valve ZZYP, ZZV, ZZVP, self operated temperature regulating valve ZZWP, ZZWEP. Valve body material: cast steel, stainless steel, chromium molybdenum steel. Working pressure 1.6-32MPA, working temperature -40 ℃ -600 ℃. Valve diameter DN15-DN200. Connection method: flange. Manufacturing standard: National standard. The principle and function of the VTON shield self operated regulating valve in the United States: The self operated regulating valve relies on the pressure and temperature of the medium flowing through the valve as energy to drive the valve to work automatically, without the need for external power supply and secondary instruments. This type of self operated regulating valve utilizes feedback signals (pressure, pressure difference, temperature) from the valve output end to be transmitted through a signal pipe to the actuator to drive the valve disc to change the opening of the valve, achieving the purpose of regulating pressure, flow, and temperature. This type of regulating valve is divided into two types: direct acting and indirect acting.
Direct acting self operated regulating valves, also known as spring loaded valves, have elastic components such as springs, bellows, bellows type temperature bulbs, etc. in their structure, utilizing the principle of balancing elastic force and feedback signals. The indirect acting self operated regulating valve adds a pilot valve, which amplifies the feedback signal and then drives the main valve disc to move through the actuator to change the valve opening. If it is a pressure self operated regulating valve, the feedback signal is the outlet pressure of the valve, which is introduced into the actuator through the signal pipe. If it is a flow self operated regulating valve, there is an orifice plate (or other resistance device) at the outlet of the valve. The pressure difference signal is taken out from both ends of the orifice plate and introduced into the actuator. If it is a temperature self operated regulating valve, there is a temperature sensor (or temperature bulb) at the outlet of the valve to drive the actuator through the Thermal expansion of the medium in the temperature sensor. Beijing Xinmeidi Valve Control Valve Series Products: Pneumatic Control Valves: Pneumatic Diaphragm Single Seat Control Valves ZMZP, ZMAP, ZMBP, Pneumatic Diaphragm Double Seat Control Valves ZMAN, ZMBN. Pneumatic precision small film regulating valve ZJHP, pneumatic precision small film sleeve regulating valve ZJHM, pneumatic three-way diversion regulating valve ZAZQ, ZMAQ, pneumatic three-way merging regulating valve ZAZX, ZMAX, pneumatic light small regulating valve ZXMAP, ZXMAN, ZXMAM, pneumatic high-pressure angle regulating valve ZMAS, ZMBS, pneumatic regulating cut-off, O-type ball valve ZSHO, pneumatic piston regulating cut-off butterfly valve ZSCW, pneumatic V-type clamp ball valve ZSHV, pneumatic piston type quick cut-off valve ZSPQ Pneumatic diaphragm piston shut-off valve ZMQ, ZSQ, pneumatic fluorine lined regulating valve ZMPF, CV3000 series regulating valve HLS, HTS, HCB, HPS, HPC, HAA, HAC, HCP, HPN electric regulating valve: electric single seat regulating valve ZAZP, electric double seat regulating valve ZAZN, electric sleeve regulating valve ZAZM, intelligent regulating ball valve ZRQO, electronic electric regulating valve ZDLP, ZDLM, electronic electric double seat regulating valve ZDLN, electronic electric three way combined regulating valve ZDLQ, ZDLX Electric three-way shunt regulating valve ZAZQ, electric three-way combined regulating valve ZAZX, electric V-type regulating valve ZKJV, electronic V-type regulating valve ZDJV, electric precision small single seat regulating valve ZAJP, electric precision small sleeve regulating valve ZAJM, precision small electronic regulating valve ZDHP, ZDHM, electric regulating butterfly valve ZAJM Self operated regulating valve: self operated pressure regulating valve ZZYP, ZZV, ZZVP, self operated temperature regulating valve ZZWP, ZZWEP. Valve body material: cast steel, stainless steel, chromium molybdenum steel. Working pressure 1.6-32MPA, working temperature -40 ℃ -600 ℃. Valve diameter DN15-DN200.
Connection method: flange.
Manufacturing standard: National standard.
The principle and function of the VTON shield pneumatic control valve in the United States explain that the pneumatic control valve is an executing unit in the pneumatic unit combination instrument and an important component of the automatic regulation system in the safety production process. It uses compressed air as the power source, receives a unified standard signal of 0-10mA (or 4-20mA), changes the valve opening, and achieves control of pipeline fluid flow, pressure, temperature, liquid level and other parameters. Beijing Xinmeidi Valve Control Valve Series Products: Pneumatic Control Valves: Pneumatic Diaphragm Single Seat Control Valves ZMZP, ZMAP, ZMBP, Pneumatic Diaphragm Double Seat Control Valves ZMAN, ZMBN. Pneumatic precision small film regulating valve ZJHP, pneumatic precision small film sleeve regulating valve ZJHM, pneumatic three-way diversion regulating valve ZAZQ, ZMAQ, pneumatic three-way merging regulating valve ZAZX, ZMAX, pneumatic light small regulating valve ZXMAP, ZXMAN, ZXMAM, pneumatic high-pressure angle regulating valve ZMAS, ZMBS, pneumatic regulating cut-off, O-type ball valve ZSHO, pneumatic piston regulating cut-off butterfly valve ZSCW, pneumatic V-type clamp ball valve ZSHV, pneumatic piston type quick cut-off valve ZSPQ Pneumatic diaphragm piston shut-off valve ZMQ, ZSQ, pneumatic fluorine lined regulating valve ZMPF, CV3000 series regulating valve HLS, HTS, HCB, HPS, HPC, HAA, HAC, HCP, HPN electric regulating valve: electric single seat regulating valve ZAZP, electric double seat regulating valve ZAZN, electric sleeve regulating valve ZAZM, intelligent regulating ball valve ZRQO, electronic electric regulating valve ZDLP, ZDLM, electronic electric double seat regulating valve ZDLN, electronic electric three way combined regulating valve ZDLQ, ZDLX Electric three-way shunt regulating valve ZAZQ, electric three-way combined regulating valve ZAZX, electric V-type regulating valve ZKJV, electronic V-type regulating valve ZDJV, electric precision small single seat regulating valve ZAJP, electric precision small sleeve regulating valve ZAJM, precision small electronic regulating valve ZDHP, ZDHM, electric regulating butterfly valve ZAJM Self operated regulating valve: self operated pressure regulating valve ZZYP, ZZV, ZZVP, self operated temperature regulating valve ZZWP, ZZWEP. Valve body material: cast steel, stainless steel, chromium molybdenum steel. Working pressure 1.6-32MPA, working temperature -40 ℃ -600 ℃. Valve diameter DN15-DN200.
