Control valves are used to manipulate the flow of fluid and are described as possibly the most important, and in some cases the most neglected, part of a control loop. Control valves, aside from heater or other device, are actuated to produce a change in the process variable of a control loop and ensure safe and efficient operation of the process.
A basic control loop process is shown below:
The Valve Manufacturers Association of America classifies the common types of valves that can be found in the industrial flow control industry:
- Multi-turn valves/linear motion valves
- Specialty valves that are customized depending on different factors such as the substance to be handled, the required flow rate, the various abilities of the valve, and maintenance and repair requirements
- Quarter turn valves or rotary valves
- Self-actuated valves
- Control valves – designed to guarantee accurate proportioning control of flow
Valves are used in various purposes in the industrial, engineering, scientific and manufacturing communities. Examples of their applications include pipelines, valves in the oil and gas industry, and valves in the food and beverage industry. Valves are also applied in the marine industry to regulate a ship’s power supply, provide water for ships with fire-fighting capabilities, store any liquid cargo, and many others. Take the example of what the Gulf Coast Air & Hydraulics did to improve Eagle Chemical Co.’s manufacturing plant, which has been shut down for several years and was in need of major renovations in its hydraulic system to bring the facilities back online. One of the changes implemented was the identification and replacement of the company’s rusty and already useless hydraulic control valves.
Emerson Process Management has released the fourth edition of the “Control Valve Handbook,” which contains information on control valve performance and the latest technologies. It contains a comprehensive guide when selecting the best control valve for an application. Armed with this handbook and partnering with an expert in the production and design of control valves, your organization may be on its way to a productive transformation.