Plumbing is all about controlling fluids (water and gases). That’s why valves are essential for any plumbing service and are found extensively in household and industrial plumbing. Valves are devices that regulate and control the flow of fluids by opening, closing, or partially obstructing the flow. Each valve has its properties and costs, but it is so important to select the right one according to your needs.
This article outlines a few important types of valves used in plumbing. Following are some common plumbing valves:
- Gate valve
- Globe valve
- Check valve
- Plug valve
- Ball valve
- Butterfly valve
- Needle valve
1. Gate valve
Gate valve is extensively used in several applications, including plumbing. It is installed in pipelines for isolation purposes only. That means it can be used to start or stop the flow of fluids completely. The gate valve consists of a rectangular or circular gate that restricts or allows the passage to the flow. The gate is completely removed from the course when the valve is open and offers no resistance to the flow. On the other hand, when the gate valve is closed, the gate makes 360° contact with the seat to provide a proper seal.
Gate valves should not be utilized for throttling purposes because they don’t offer precise control. Moreover, with a partially open gate valve, there is a great risk of damage to the gate due to the high velocity of the fluid. Gate valves are operated by a threaded stem and require multiple turns to fully open or close. These valves are easy to maintain and perform well in high temperature and pressure applications.
2. Globe valve
Globe valve is a spherical-shaped unidirectional valve that can start, stop, and throttle fluid flow. It consists of a disc or plug which sits on a stationary seat ring. The disc is connected to the stem, and it is further attached to a handwheel, which rotates to open and close the valve. The disc moves perpendicular to the seat as you turn the handwheel. Compared to the gate valve, the globe valve’s seat provides a tighter seal due to right-angle contact with the disc.
Globe valves are used in chemicals, oils, feed-water, and other plumbing services. Additionally, they are ideal for any application where pressure drop is not concerned. Depending on the body type, globes valves are of three types; z-type, y-type, and angle-type globe valves. Their main function is to provide reliable throttle. However, it is heavier and offers a high-pressure drop than other valves.
3. Check valve
Check valve, also known as a non-return valve, prevents the backflow of fluid in a pipeline. This plumbing valve is operated automatically without any external control. It works on pressure difference; higher pressure on the inlet side than outlet side will open the valve while higher pressure on the outlet side will close it. Typically, its body is made of brass, stainless steel, or plastic. It has two openings, one for the fluid entrance and the second for the fluid exit. Furthermore, check valve comes in various types, sizes, and prices for different applications.
The check valve is a one-way valve whose primary function is to protect the pipelines from water hammers by preventing the fluid from flowing back. It is a simple, easy, and cost-effective solution for backflow issues. Water and wastewater treatment, pumps, pipelines, and chemicals are some of the plumbing applications that feature check valves.
4. Plug Valve
Plug Valve consists of a conical or cylindrical plug with a hollow passageway inside the valve body. It is a quarter-turn valve, which means a quarter-turn motion will align the pipe with the hole, and fluid will begin to flow. And a 90° turn from here will lead to a closed state which will stop the flow. Plug valves are ideal for commercial and light industrial applications, including plumbing services. Moreover, due to its smooth, multi-port designs, plug valves can find applications in many other sectors as well.
Plug Valve is leak-free and provides minimum resistance to the flow of the medium. It is durable as there is a lower risk of corrosion because the actual plug and seat do not get exposed to line fluid. However, it is not meant for throttling applications and requires more force for actuation due to high friction.
5. Ball valve
The ball valve is another quarter-turn valve that controls the flow of fluid with a pivoting ball. This pivoting ball has a hole or bore in the center; it is connected to the stem, which helps rotate the ball to open or close the valve. There are two significant types of ball designs; floating and trunnion. Floating balls are ordinary and cheaper than trunnion balls. Ball valves can have multiple ports; there are two-way, three-way, and four-way ball valves are available.
The ball valve is commonly made of durable materials such as PVC, stainless steel, bronze, or brass. The ball valve is compact compared to other valves and offers fast shut-off speeds. Besides, it works well in high-pressure and high-temperature environments. Due to these qualities, the ball valve is perfect for shut-off and control applications and is preferred over gate and globe valves. However, it lacks in providing precise control in throttling applications.
6. Butterfly Valve
Butterfly Valve has a rotating disc that acts as a gate to start, stop and regulate the fluid flow. The disc is bored and connected with a handwheel through a stem. In the closed state, the disc blocks the flow, while in the opened position, the disc is become perpendicular to the flow direction to allow the fluid to flow. Furthermore, there are multiple ways to actuate a butterfly valve; manual, semi-manual, or fully automatic.
The butterfly valve is also a member of the quarter-turn valve family. With the economic design, it offers low installation costs and maintenance requirements. The butterfly valve is suited to handle large volumes of fluids like in water treatment plants, water distribution systems, and pumping stations. It is quite versatile and can be installed underground as well.
7. Needle valve
The needle valve uses a threaded, tapered pin to offer precise control in small diameter pipelines. The pin is connected to a handle and moves up and down as you turn the handle. Also, a locking pin prevents the pin from fully unscrewing. The valve body is usually made of brass and stainless steel due to its chemical-resistant properties.
The needle valve design is similar to that of the globe valve, with the only difference being a sharp needle-like disc. It is used in flow metering applications when a constant low flow rate is required to be maintained.