What is the working principle of control valve?

Control valves are valves used to control conditions such as flow, pressure, temperature, and liquid level by fully or partially opening or closing in response to signals received from controllers that compare a “setpoint” to a “process variable” whose value is provided by sensors that monitor changes in such …

Is gate valve a control valve?

Gate valves are designed for fully open or fully closed service. They are installed in pipelines as isolating valves, and should not be used as control or regulating valves. A gate valve is a multiturn valve meaning that the operation of the valve is done by means of a threaded stem.

What is the main purpose of a control valve positioner?

A positioner for a control valve is used to adjust a valve’s position based on a desired setpoint for a process variable, whether it be pressure, temperature, or flow. Types of valve positioners include pneumatic, electro-pneumatic, and digital.

What does Valve mean?

noun. any device for halting or controlling the flow of a liquid, gas, or other material through a passage, pipe, inlet, outlet, etc. a hinged lid or other movable part that closes or modifies the passage in such a device.

What is control valve trim?

What is Control Valve Trim? High Pressure Control Valve trim consists of three basic items: the stem, ball, and seat. These are the operative parts that control the flow of liquid and gas through a valve. They are also the parts most exposed to process elements, and therefore most vulnerable to wear.

What are the 3 most common control valve flow characteristics?

The three most common types of flow characteristics are quick opening, equal percentage and linear.

What is equal percentage valve?

An equal percentage flow characteristic is a nonlinear curve of which the slope increases as the valve opens, while a linear flow characteristic is a straight line (Figure 1). Figure 1. Control valves manipulate the rate of liquid/gas flow through them by altering the open area through which the liquid/gas passes.