Various styles, sizes, materials, and connections are available for valves. The right valve should be selected based on the task (control or on/off), the service conditions, the fluid (liquid, gas, combustible, corrosive, etc..), and the load characteristics of your application. When selecting your valve, keep these suggestions in mind:
1. Valve size:
Matching the valve’s size to the expected flow through the system is important when choosing a valve. Valve flow coefficients (Cv), or valve characteristics. Are use to determine the right valve size while maintaining stable flow. The following equation can use to calculate CV:
A common mistake is calculating a Cv based on the maximum flow rate, which results in an oversized valve. For proper valve sizing, it is important to consider the range of flow rates (min, max, and mean). Nevertheless, it is important to choose a valve whose Cv value is sufficiently larger than the calculate Cv so that they expect flow performance can achieve.
2. Valve types:
Here are some common valve types and their general usage, along with a short description of their distinct advantages & disadvantages:
|Ball Valves||It is normally limit to an “on-off” control function (fully open or fully close positions).||They are reliable, cost-effective, require little maintenance, are diverse (available in a wide range of sizes and materials), and offer full unrestricted flow.||It has limited throttling characteristics, and it is difficult to clean, which can lead to contamination.|
|Needle Valves||It is used to control a low flow rate precisely and consistently (modulating) in flow metering applications||Precision and control, flexibility, resistance to both hot and cold temperatures, and the ability to withstand constant high pressures and vibrations.||It has a high pressure loss, can only be used at low flow rates, and its seat and needle could be damaged if not operated carefully.|
|Globe Valves||It is use for regulating flow and pressures as well as shutting off a flow completely.||It has a good shutoff capability, a shorter stroke (compared to gate valves), and can be used in high-pressure systems.||There is a high pressure drop (head loss), it is unidirectional, the opening speed is slower, and it is not suitable for clean or sterile applications.|
|Gate Valves||It can use in either the fully open or fully close position. The flow rate of the fluid is not proportional to how much the valve is open, so it is not usually use to regulate flow.||It has low fluid resistance, is energy efficient, and has unobstructed flow (does not decrease pressure).||Low pressure, slow-acting, bulky, not drip-tight shutoff, do not partially open as it will damage the seat/disc.|
|Butterfly Valves||This valve is use to regulate flow and is available in both fully open and fully close positions. Water and slurry applications require them to perform well.||Opens quickly is lightweight, reduces space requirements, and requires less maintenance.||As compared to ball valves and globe valves, their flow adjustment range is small. They are not suitable for high-temperature or high-pressure piping systems, and their sealing performance is poor.|
|Plug Valves||Similar to ball valves, the control is on-off.||High reliability, long service life, and ease of use.||A higher initial cost than ball valves, and no throttling capability.|
3. Chemical and Environmental Compatibility:
Corrosion Resistance: For a valve to function properly, it must be made of a material compatible with the gases or liquids that flow through it. Chemical reactions will cause unsuitable valve materials to deteriorate in hostile environments.
Pressure: It is important to consider the pressure ranges where the valve will be installed. A valve’s strength is its ability to withstand the internal stresses generated by containing and controlling a fluid under pressure
Temperature: Choosing the right valve material for your application depends on the operating temperature. A valve’s material strength will change when the temperature is raise, usually becoming softer and weaker.
Environment and Maintenance: What type of environment your valve will be installed in and what does this means for its maintenance? A harsh environment includes extreme cold/heat, saline, moisture, acidic/alkaline, etc.
Aira Euro Automation is a Leading Valve Manufacturer & Exporter in India. We Have a Wide Range of Industrial Pneumatic Actuated & Manual Valves.