A Guide To Choosing Control Valves
Did you know that at least 30,000 gallons of water can be saved for a family of four when control valves are properly used in residential settings? Imagine how much water can be saved for other applications, especially for commercial projects with expected high consumption rates of water. Control valves are essential pieces used to control and modify the rate at which fluid flows.
They do more than control and modify flow, and that’s why they’re important in multiple processes. From saving water and money to enhancing safety measures while reducing unneeded energy consumption and strain on different systems, these tools are vital for most engineering processes.
There is no one size fits all control valve for every application so, to find out how to size your equipment for the proper valve fit, keep reading.
The Different Types of Control Valves and Their Applications
Knowing the types of control valves most appropriate for your applications can save money and ensure you’re using the proper equipment. While there are a variety of valves on the market, there are four primary types.
Ball valves use a ball that pivots and it’s also perforated and hollow in design and that ball helps to control the flow of fluids. When the valve is blocking fluid flow, the ball will pivot about 90 degrees. When it’s open, the hole of the ball will be flush with the opening of the valve’s inlet.
This type of valve is very prone to blockages, although they do have high-efficiency ratings. If you are using operations that involve gas or oil production, this would be an appropriate choice.
This type of valve gets its name from its shape. Most often, you will see this valve being used in pipe-planting operations.
You can use them with either manual or automatic control as well. What makes them different is that they can be used for complete shut-off options. They can also regulate the flow and pressure of the liquid that’s used.
Butterfly valves are extremely versatile. They can help regulate fluid flow like the other options but they are flexible based on the industry. They can be used in pharmaceutical facilities, for wastewater treatment, and even in pipeline modifications and fire prevention applications.
Plug valves are often used in lighter applications. They are popular choices for directional flow and adjusting to low-pressure applications.
This also applies to lower-temperature projects. Plug valves are more so seen in chemical servicing plants and corrosive substance processing applications as well as oil piping facilities.
How to Tell What Size Is the One You Need
Calculating the size you need can be a bit difficult. The overall goal is to find the size that matches the material you will be using and the flow rate of that material. This means that if you will be using anything other than water, the formula will be different.
The valve coefficient is what’s used to help figure out the exact size. Most of the time, you won’t need to calculate the size manually as most product materials and manuals will include the sizing charts with the appropriate values listed.
For water, you will need to take the flow you need represented in gallons per minute (GPM) and divide it by the difference in the pressure given off between the inlet and the outlet of the valve, or in other words, the psi. For anything other than water, you will need to account for the gravity of that material.
The Importance of Proper Sizing
Sizing control valves are one of the most important things you need for valve selection before installing them into your system. You don’t want to install a valve that’s too big or too small for your application because it can cause damage to the system and make it inefficient or cause damage to the machine itself and the operators using them if not using a remotely-operated system.
If you have too small of a valve, the flow rate your application requires won’t be reached once you open the valve fully. Also, it might cause the system to back up or create too much pressure. This could cause an excessive amount of output which could result in cavitation of the valve.
You have to also realize that the valves will experience flashing at this point. If you have too large of a valve, it might cause the system to run slowly, wasting energy and money and you will end up with a higher stroke count. This will ultimately result in wearing down the trim of the valve, which will end up needing to be replaced faster than it would if you had the right size.
Keep in mind that using valves that aren’t sized correctly will cause your equipment to operate outside of the parameters that it should. This could cause excessive and sometimes, irreversible damage to not only the primary equipment but the entire system that’s used.
Actuator and Positioner Selection: What to Know for Control Valves
A valve actuator is something you’ll need to operate your valve and it’s exactly as it sounds. It’s a device that uses power to operate and control the valve you’re using. Also, it doesn’t matter what power source you’re using as you can use the compressed air method or a system that runs off of hydraulic power.
Rotary and linear are the two types of actuators that you can use. If you didn’t realize, there is one actuator for both of the main types of valves that need them to operate. The control valve itself should be located anywhere that it can be accessed from different platforms on your site and the reason for this is safety.
You also need to consider selecting positioners. A positioner is the electronic device that regulates, modifies, and controls valve positioning based on a computer program. A positioner can be used instead of a manual actuator to regulate the position of the valve which could make it easier to use depending on your project.
A positioner uses sophisticated technology and sensors to fully control and regulate the valve and there are three main types;
- Digital Valve
The reason this is important is that the positioning of the valve may require a different type. It’s important to note that you can configure your control valves without a positioner in some cases so it heavily depends on the application.
The Quality Materials You Need
The control valves you use will be dependent on the application you are using them for. There are certain options for low and high-pressure projects. The same goes for temperature and flow direction parameters.
If you get the proper size, you could ensure higher safety and efficiency ratings for your applications. You can also save the time and money that it takes to complete or run certain operations.
Working with Anything Flows allows you to get high-quality equipment for every job you have. Contact us today to get the instruments you need, the first time.