The working principle of the pneumatic control valve

Used for regulating the flow of medium, pressure and liquid level. According to adjust the position signal, automatic control valve opening, so as to achieve the adjustment of the medium flow rate, pressure and liquid level. In the automatic control of modern factory, pneumatic control valve plays a very important role, the production of the factory depends on the correct allocation and control flow of the medium. These controls both the exchange of energy, pressure reducing, or is a simple container loading, will need some final control elements to complete. ACTS as the variable resistance in the pipeline. Its change process fluid turbulence scale, or provide a pressure drop in the case of laminar flow, pressure drop is caused by resistance change valve or 'friction'. The pressure to reduce process is often referred to as 'throttling'. Under the condition of the liquid pressure, which is turbulent or viscous friction consumption, both of which put pressure is converted into heat energy, lead to an elevated temperature slightly. For gas, it is close to isothermal adiabatic condition, deviation depends on the degree of non-ideal gas ( Joule Thomson effect) 。 Common control circuit includes three main parts, the first part is the sensitive element, it is usually a transmitter. It is a device used to measure the modulated process parameters, the parameters such as pressure, level, or temperature. The output of the transmitter was sent to adjust the instrument - — Regulator, it determines or expectations and the process parameters and to measure a given value deviation between the actual value, one by one, the correction signal is sent out to final control element. Valve to change the flow of the fluid, the process parameters to achieve the expectations. Belong to the control valve series, the main function is to regulate the medium parameters such as pressure, flow, temperature, is the final control element in process loop. Aka control valve, by accepting conditioning control unit of the output control signal, from engine operation to change fluid flow. And valve general, the executing agency. If by their ticket enforcement agencies use the power, can be divided into pneumatic, electrical, fluid movement three, namely to compressed air to power sources pneumatic pneumatic control valve, based on electric power sources of electric pneumatic regulator, as a liquid medium ( Such as oil, etc. ) Pressure as the power of electric hydraulic pneumatic control valve.