Control Valve

Working principle of control valve

The operating principle of the control valve is to control the flow of fluid by adjusting the size of the flow path. The valve body provides a path for fluid flow, while the valve internals regulate velocity and direction. Valve internals include such internal components as plugs, seats, stem, and other internal components that interact with fluid flow to regulate velocity.

The valve actuator generates the force needed to move the stem and control the flow of fluid. Depending on the requirements of the application, the actuator can be pneumatic, electric or hydraulic. When the control signal is received, the actuator moves the stem, thereby changing the position of the valve internals, thereby regulating the fluid flow.

The valve positioner receives a control signal from the controller to determine the desired flow rate. The positioner then adjusts the position of the valve to maintain the desired flow rate. Depending on the requirements of the application, the positioner can be pneumatic or electric.

Instruments that control valves include sensors and other devices that measure process parameters such as pressure, temperature, and flow. This information is used to provide feedback to the controller and ensure that the desired flow rate is maintained.

Pressure control valve (PV)

As the name suggests, a pressure control valve or PV is a valve commonly used to regulate and control fluid pressure in a system. The main function of the valve is to maintain a consistent pressure level within a specific range, regardless of whether the upstream or downstream pressure changes.

The operation of the pressure control valve involves opening and closing in response to pressure changes, which helps regulate the flow of fluid through the system. If the pressure exceeds the set point, the valve opens to allow the fluid to escape and reduce the pressure. Conversely, if the pressure drops below the set point, the valve closes to prevent fluid from escaping and increasing the pressure.

Flow control Valve (FV)

A flow control valve or FV is a valve that helps regulate and control the flow rate of fluid in a system. It works by changing the size of the valve opening to maintain a consistent flow rate within a specific range, regardless of what is happening upstream or downstream.

If the fluid flow rate exceeds a predetermined level, the stem lowers the spool to reduce the opening size and reduce the flow rate. Conversely, if the flow rate drops below the set value, the stem lifts the spool to increase the opening size, allowing more fluid to pass through.

Temperature control Valve (TV)

The temperature control valve is usually installed in a pipe or container within the treatment system, and it is connected to a temperature sensor that monitors the temperature of the fluid or treatment system. If the temperature is above or below the desired set point, the valve will adjust the flow of hot or cold fluid to maintain the desired temperature range.

Level control Valve (LV)

A level control valve or LV is a device used to maintain a consistent level in a storage tank or container. Its working principle is to adjust the flow of liquid into and out of the tank according to the change of the liquid level. The valve ensures that the level is kept within a specific range, which helps prevent overflows, underflows, or other problems.

Manual control valve (HV)

A manual control valve or HV is a valve that is manually controlled by a handle or lever. They are often used in applications where manual control is required or preferred, especially in low-voltage or small-scale systems.

Remote Operation Shut-off Valve (ROSOV)

A remote operated shut-off valve or ROSOV is a control valve that can be controlled remotely by an electronic device or computer. These valves are used in a variety of industrial Settings, including oil and gas pipelines, water treatment facilities and chemical plants. They are usually installed in hard-to-reach or dangerous locations, such as deep underground or at sea.