Electric control valve
Electric regulator components include: electric actuator, between the actuator and the valve fittings, valve parts, valve core is the core of the valve components, its principle is that connected the stem and electric actuator, electric actuator control system control the transmission of signals and the implementation, the current valve positioner valve and actuator, we can know if the dead zone, by executing a command implementation throttling mouth opening change, the final adjust medium flow, electric drive compared with those of other wide power supply, convenient operation and fast optimal Lou include: the implementation process of electric control valve when the pipeline fluid parameter changes (such as flow, pressure), these parameters through the PID calculation, one of 20 ma (4) the analog current signal is passed to the RTU upper machine, and then through the deviation signal (4 to 20 ma) to the electric actuator, the opening of the pressure and flow control can be realized through regulating valve stem in signal to move up and down,
Self-reliance type pressure regulating valve
Self-reliance type pressure regulating valve series (FL) can be divided into two parts, the first part is the voltage regulator, is mainly composed of valve core, a fixed seat, diaphragm and spring connection, etc, in the condition of equilibrium, the downstream pressure P2 (pressure pipe through guide into to the low pressure valve cavity) connected to the diaphragm spring pressure PM with load pressure Pv (upstream pressure PI regulation of junior people via the command to the high pressure valve cavity) phase equilibrium "in the second part to control apparatus, when using self-reliance type pressure regulating valve outlet pressure is set to the voltage regulator, is through the adjustment screws G, to spring compression of MS degree change of command device, so as to set the outlet pressure, the profile control process is given when the outside world a jamming signal (gas and the change of inlet pressure), the parameters are tuned change (outlet pressure), to the measuring element, a signal measuring element and the given value comparison, get the deviation signal, and be sent to the transmission device, transmission device according to the deviation signal displacement signals sent to the regulating mechanism, make the valve action, regulating object role to adjust output a signal to interference effects,

A gas areas use problem analysis
A gas station in website building, on the way of sichuan gas pipe used DN80 electric regulating valve is made up of FISHER regulator and BIFFI external regulation electric actuators, in be used actually, when using automatic adjustment function, actuator repeated movements, oscillation system cannot work normally, basically has the following reasons:
According to the best flow control curve of FISHER regulator valve opening should be within the scope of 40% to 90% adjustment, if always let the regulator within the scope of work in a small open degree, cavitation, erosion will damage the valve core, shorten valve life, in addition, small open degree of flow speed, noise,
Because domestic gas peaks and troughs, the requirements and conditions in the flow of constant pressure is the most important at the same time, due to the large in nanchong regulating valve selection system can work normally, and the advantages of constant pressure is self-reliance type pressure regulating valve,
Single in terms of function, and electric control valve is mainly used for long-distance pipeline of medium pressure and large flow rate adjustment, self-reliance type pressure regulating valve used for relatively small flow of medium pressure setting,
At the same time, in the gas zone also used three DN 0 of the tower tower, self-reliance type pressure regulating valve regulating, in use process due to P2 + PM> Pv, the valve core will move to the position of the fixed seat opening decreases, and flow rate decreases, and analyze reasons are as follows:
When the pipe diameter must be the size of the differential impact velocity, and the size of the flow velocity is related to the size of the traffic, for gas, improvement of stress result in the same line at the time of gas flow through the same party, the real flow rate decreased, thus for gas flow and pressure is a relationship, when the pressure of gas transmission line more close to the design and use of self-help type pressure regulating valve adjusting flow will be more difficult, this is the advantage of electric control valve,
If you want to meet with self-reliance type pressure regulating valve to ensure flow should reduce the pressure difference, is bound to add another to the secondary voltage regulation, this will increase the cost of investment, the venue construction difficulty increases, the regulator can be set arbitrary its opening meet traffic demand,