Process Control Valves: Types, Selection and Applications
Process control valves are vital components of process control systems that seek to automate industrial processes in a safe and efficient manner. This is achieved by regulating the flow of liquids within pipelines for a variety of applications across many industries. The selection of process control valves is dependent on the fluid being managed, the operating conditions, the characteristics of the process and the desired performance. It is essential to ensure that the most suitable valve is chosen in order to allow a safe and reliable operation. This article outlines the types of process control valves, the selection criteria and different applications relevant to industry.
Types of Process Control Valves
There are various types of process control valves available depending on the flow characteristics, applications, properties and media being managed as part of the process. Generally, process control valves can be divided into two categories; pressure-dependent and flow-dependent.
Pressure-dependent valves are designed to maintain the pressure across a device, for example a pressure relief valve. These types of valves are used to protect plant and meet safety requirements. In contrast, a flow-dependent valve is designed to maintain the flow rate of a liquid under dynamic conditions.
Within these categories there are a variety of valves that incorporate different designs, such as the globe valve, ball valve, butterfly valve, diaphragm valve, plug valve and needle valve.
Selection Criteria
The selection of process control valves should be based on application-specific requirements and fluid characteristics. Generally, there are five main selection criteria which a valve should satisfy; application, performance, cost, availability and design features.
Application- The valve must be able to effectively carry out its required function, such as open/close or pressure limiting. Performance- The valve must provide a reliable performance level with regards to fluid flow. Cost- The selected valve should provide the best value for money by taking its performance into account. Availability- The valve should be available from stock or with a short lead time. Design features- The valve should incorporate features that are necessary for the application, such as flange compatibility and body material.
Applications
Process control valves are widely used in many industries, including oil and gas, petrochemicals, food & beverage, water & wastewater, marine and manufacturing. Applications of process control valves include controlling flow, pressure relief and pressure regulation of fluids within a process. For example, a butterfly valve is commonly used to control fluid flow in the oil industry, while a plug valve is used to regulate the pressure of fluids in a water distribution system. Furthermore, they are used in combination with other equipment, such as pumps, hoses and pressure regulators, to ensure a safe and efficient operation.
Conclusion
Process control valves form an integral part of many industrial processes. It is therefore important to choose the most suitable valve for a particular application in order to provide a safe, reliable and cost-effective performance. The selection of process control valves should be scrupulous and should consider the application, design features, performance, availability and cost. These valves have a wide range of applications across many industries and are used in combination with other equipment to ensure a safe and efficient operation.
