Plumbing is mainly about controlling the flow of water, gas, and other things. If you want to control the water/gas flow, you’re going to need plumbing valves. There are a lot of things to consider when manufacturing and choosing the right valve for the purpose it may serve.
There are several ways that valves can be used in plumbing, and choosing the right one needs thorough research on how it’s going to be used, and the help of a manufacturer or professional.
There are a number of different plumbing valves used to control the flow of water and gas
in a building. In this article, you will learn the different types of valves, how they work and their pros and cons.
Gate Valves
Gate valves are the sliding types of valve. In this type, the closing part is a metal gate. It slides down to seal the valve. In fully-opened conditions, the pipe’s area is equal to the flow area. Therefore, there’s an inconsequential drop of pressure across the valves.
These valves are ideally used for on-off purposes. It’s not advisable that they are utilized for throttling as the erosion of the gate may happen in partly-opened situations.
In partially-opened situations, the valve is vulnerable to wear and tear due to the vibrations.
Moreover, during opening and closing, there’s a significant amount of friction. As a result, opening and closing gate valves frequently and quickly aren’t possible.
Gate valves are useful in petrochemical industries because they work well with metal-metal sealing.
The Advantages of Gate Valves:
- They have resistance to little fluid, which means the sealing surface can’t be eroded easily by the medium.
- Operation is labor-saving
- The design is simple, excellent manufacturing performance, and a full scope of application
The Disadvantages of Gate Valves:
- The structure is a bit complicated.
- Erosion and abrasion can likely happen between the sealing surface.
- Maintaining it can be difficult.
- Has a bigger dimension, it requires more space to open properly.
- It requires time during the opening and closing process.
Plug Valves
These valves are quarter-turn types. They consist of a plug, which can be conical or cylindrical in shape. The plug contains a slit, which stays in-line with the flow during an open condition. When the plug turns ninety degrees, the slit changes into a perpendicular shape to flow, and the valve becomes closed.
The plug valves are suitable to control liquids with suspended slurries, solids, oils, etc. Also, they are mainly used for on-off operations. If they are used for throttling applications, the pressure drop is higher due to the incorrect arrangement between the opening or slit direction and the flow direction.
The Advantages of Plug Valves:
- They have a simple design that comes with a few parts.
- Easy to open and close
- Low resistance to flow
- Has a decent leak-tight function
- Multiple-port design reduces the number of valves required
- Smooth maintenance can be achieved
The Disadvantages of Plug Valves:
- The prices for plug valves may be higher compared to ball valves.
- The big valves can’t be controlled by hand and will need an actuator.
- It needs more force to control.
- Pressure drop because of reducing port
Butterfly Valves
Butterfly valves have the simplest design; however, they are the most versatile. They’re quarter-turn controlled valves, which are usually used in different industries for various operations. Quarter-turn applications make sure that valve operation is quick. During open conditions, there is a minimal obstruction to the flow of fluid through the butterfly valve as the flow goes around the wedge smoothly. As a result, there is a low-pressure drop through the valves.
Due to its unique method of application, the butterfly valve can be activated without the need for high torques, as well as wear and tear. Because there isn’t any friction, the use of heavy actuators is prevented.
The Advantages of Butterfly Valves:
- When pneumatically actuated, they can be opened and closed quickly.
- They are small.
- The disc is lighter compared to the ball, which makes the valve require less support compared to a ball.
- They are precise, which makes them ideal in industrial operations.
- They require minimal maintenance.
The Disadvantage of a Butterfly Valve:
- The downside of using a butterfly valve is that there are some parts of the disc are always exposed to the flow, even when they are fully opened. Therefore, when using a butterfly valve, the result will always cause a pressure switch across the valves, regardless of the conditions.
Globe Valves
The globe valves are linear motion types of valves. They are mainly used in both throttling and on-off operations. In these valves, the fluid flow through the valves will follow an S-path. Because of this, the direction of the flow will change twice, and as a result, the high pressure will drop.
Because they offer several benefits, the globe valves are typically used in operations where pressure drop through the valves is not a significant factor.
Globe valves are not commonly used when the sizes are more than NPS 12 (DN300) as massive forces are released on the stem to open and close the valves under liquid pressures.
These valves need high pressures on the seat so they can remain sealed when the liquid releases pressure from the base part of the disc.
They are commonly used for both throttling and on-off operations, but special kinds of trims are needed for throttling operations wherein massive pressure drops are engaged.
The globe valves can be used in several arrangements, depending on the type of operation. These can be:
- Wye Pattern
- Tee Pattern
- Angle Pattern
The Advantages of Globe Valves:
- Excellent shutoff capacity
- Great valve throttling
- Shorter stroke in contrast to gate valves
- Can be utilized as a stop check valve
The Disadvantages of Globe Valves:
- There is a higher pressure drop in contrast to gate valves
- Needs more force or a bigger actuator to seat the valve
Pinch Valves
A pinch valve is comprised of a plastic sleeve or tube, which is made out of supported elastomers. The closing or sealing mechanism is done by pinching or throttling the sleeve or tube.
This type of valve is well-suited for controlling liquids and slurries that have suspended solids.
They must be used as on-off valves when they are used with abrasive slurries.
The Advantages of Pinch Valves:
Pinch valves provide more benefits compared to the other valve types.
- They can be used in managing corrosive liquids since there isn’t any contact between the valve system and the being liquid transported. Since there isn’t any contact between the medium transported and the metal parts, the pinch valves are excellent for food-grade operations.
- They are, in general, ideal for low-pressure operations.
- Lightweight
- Easy to maintain
- Less consumption of air
- Minimal friction and turbulence
- Self-cleaning
- No extra actuator needed
The Disadvantages of Pinch Valves:
- The sleeves will get worn out when used for throttling applications.
- The range of temperature is limited.
- Limited medium-operating pressure
- Face-to-face length might be a concern when there is limited space for fitting the valve.
Disc-check Valves
Disc-check valves also called as non-return valves, enables the flow to go through them in a single direction and seal the current in the opposite direction. Due to this special directional feature, these valves are used principally for some significant operations in the steam mechanisms.
The Advantages of Disc-check Valves:
- They’re self-actuated and don’t need any external methods to actuate the valves to open and close.
- They’re fast-acting
The Disadvantages of Disc-check Valves:
- They can stick when in an open position.
- They have limitations on installation arrangements.
- Since the parts are enclosed, it’s hard to identify if the valve is open or sealed.
Conclusion
In plumbing, there are no one-size fits all. All these valves are designed for different plumbing systems under different circumstances. Some will excel in a particular operation, while others will fail. You must focus on your medium, whether it’s water, gas, or other properties. You should pay attention to other elements as well, such as pressure and temperature. If possible, please turn to professionals. Hopefully, the information provided will help you in deciding which plumbing valve is perfect for your application.
English 
Español