Control Valve

A Control Valve is a type of valve which is designed to control fluid flow in a pipe by varying the size of the flow passage / orifice as directed by a signal from a controller. This allows the direct control over the flow rates, pressure, temperature and liquid flow.

Control Valves comprises of a valve body – stem, seat, trim and plug & a valve actuator.

They are made from various types of material, like Carbon, or Stainless Steel.

How a Flow Control Valve works?

The desired flow of a control valve is achieved by opening, closing, raising, or lowering of the valve plug, onto or away from the seat which is connected to the valve stem.

This is used to control the coefficient of flow CV (American Imperial) or the KV ( European Metric). The use of the coefficient of flow of a valve offers a standard method of comparing valve capacities and sizing valves for specific customer applications that is widely used in industry.

The amount of flow of the control valve depends on the signal received from the feedback device, a flow meters value normally fed back to a PLC, in turn the PLC will carry out a logic value comparison of a recipes fixed value, then vary the value of a 4-20ma or 0-10Vdc output signal provided to the controller, this in turn uses a complex algorithm, to allow the output device to supply the correct amount of air or electric to the actuators, which in turn adjust the Valve Stem (stroke) this is proportional to the required percentage flow required.

This enables the direct flow control and the consequential control of process quantities such as pressure, temperature, and liquid flow, to ensure the correct amount of medium arrives at the desired time, this can then enable the process to be controlled to the required tolerance, with a fully closed loop process.

Control Valve Actuator Types;

A valve actuator moves or controls a device such as a valve. A control valve actuator responds to a signal using an outside power source. These outside power sources maybe in the form of Pneumatics, Electronics or Hydraulics.

The types of a Control Valve Actuator vary from Linear to Rotary.

Linear Actuators includes;

Diaphragm with spring return
Piston with spring return

and Rotary Actuators includes;

Diaphragm with spring return
Piston with spring return
Link Coupling
Rack & Pinion

How Flexachem can help you?

Flexachem is the leading distributor for the sizing & design of Control Valves throughout Ireland. We have a dedicated Valve Specialist team who are highly experienced and industry trained to assist you with any simple to complex application. Our Service Engineers provide localised technical support & on-site service engineering to support your operational needs.

We supply Flowserve’s general service and high-performance control valves – linear and rotary – with pressure ratings of ANSI Class 150 to 4500/PN 10 to PN 640.

Flowserve Control Valve Brochure