Detailed description of how to choose the control valve model

So what is a regulating valve? Regulating valve, also known as control valve, is the final control element in the field of industrial automation process control. It changes the process parameters such as medium flow, pressure, temperature and liquid level by receiving the control signal output from the regulating control unit and relying on electric power operation. Generally, it consists of actuator and valve. There are many kinds of regulating valves, how to choose them?

First, how to choose the control valve model

When selecting the type of regulating valve, the function should be considered first. According to the temperature and corrosion properties of the pipeline conveying medium, the temperature resistance, corrosion resistance (corrosion resistance, cavitation and erosion), anti-clogging, pressure difference △p (including normal working pressure difference and pressure difference when the valve is closed) and leakage of the control valve should meet the technical requirements. This aspect is mainly reflected in the valve body of the control valve.

And control valve parameters. The selection of control valve parameters mainly includes action mode selection, adjustment speed selection, adjustable ratio check calculation, flow characteristic selection, valve diameter selection and accompanying opening check calculation. This project is mainly about the selection of technical parameters of control valve actuator.

2. What types of control valves are available?

(1) Pneumatic control valve

(1) is classified according to the form of pneumatic actuator.

(a) membrane actuators. It can also be divided into direct installation (positive action and reaction) and side installation (positive action and reaction).

(b) The piston actuator is divided into proportional type (positive action and reaction and two-position type).

Long stroke actuator

(d) rolling film actuator.

② According to the regulation form, it can be divided into: (a) regulation type; Cut off; (c) adjust the cut-off type.

(3) According to the action type: (a) straight stroke; (b) angular travel.

④ Classification according to the shape of valve core: (a) flat valve core; (b) a plunger-shaped valve core; (c) a window-shaped valve core; (d) a sleeve-shaped valve core; (e) multi-stage valve core; (f) deflecting the valve core; (g) butterfly valve core; (h) spherical valve core.

⑤ Classification according to flow characteristics: (a) Linear type; Equal percentage; (c) parabola; (d) driving fast.

⑥ According to the form of the upper valve cover, it can be divided into: (a) ordinary type; Heat dissipation (absorption) type; (c) long neck type; (d) bellows seal type.

2) Electric regulating valve

① According to the form of electrical professional title organization, it can be divided into: (a) Angle line; (b) straight strokes; (c) multi-rotation type.

(2) According to the attachment form: (1) servo amplifier; Limit switch.

③ Classification according to flow characteristics: (a) linear type; Equal percentage; (c) parabola; (d) driving fast.

④ According to the form of upper cover, it can be divided into: (a) ordinary type; Heat dissipation (absorption) type; (c) long neck type; (d) bellows seal type.