What is a Valve?
A valve is a device for controlling the flow of fluid or air via a pipe, duct, etc., particularly an automatic device that allows movement in just one direction.
Here are some distinct types of valves that have been developed for specific use. Some valves are designed to work in specific settings, while others are designed to exclusively allow the flow of specific substances. Other valves, depending on their make and configuration, can be utilised in a variety of applications or conditions. As a result, it is critical to understand the many types of regularly used valves and what they are used for.
What is Control valve stem?
Types of Valves
There are six different types of valves developed for various purposes in the industry. They are
- Gate Valves
- Ball Valves
- Butterfly Valves
- Globe Valves
- Needle Valves
- Check Valves
What is Poppet valve and How it works?
Gate Valves
In industrial plumbing, gate valves are the most widely utilised valves. They are also utilised in residential piping on occasion. Gate valves offer a considerable advantage since they restrict less material flow and result in a very low-pressure drop within the valve. They have a sliding metal gate that slides up and down to open or close the pipe’s passage, permitting or stopping the flow.
Applications of Gate Valves
Gate valves are frequently seen in sewage and water distribution pipe systems.
Advantages and Disadvantages of Gate Valves
Advantages of Gate Valves
- Available in large sizes
- It can be used in slurries and viscous liquids
- Used as a shut-off valve
- Easy to maintain and disassemble
- Inexpensive
- Bidirectional
Disadvantages of Gate Valves
- Low-pressure limitations
- Slow open and close time
- Poor throttling characteristics
- Difficult to repair
- Should not be used in sanitary applications
Ball Valves
Ball valves have a quarter-turn operation. They are made of a spherical ball (thus the name) with a hole in it. When the valve is open, the hole aligns with the flow of the pipe, allowing the substance to pass through. When it is closed (by 90-degree rotation of the spherical plug), the hole becomes perpendicular to the flow and stops it.
Applications of Ball Valves
Ball valves are typically utilised in cut-off applications, such as systems that handle steam, water, air, oil, and corrosive fluids. They can also handle dusty, dry fluids and slurries, but should not be utilised with fibrous or abrasive materials.
Advantages and Disadvantages of Ball Valves
Advantages of Ball Valves
- They have a compact and low-maintenance design that does not require lubrication.
- They are the most cost-effective of all valves.
- The most significant advantage of ball valves is that they have poor throttling characteristics, which can readily erode the seat of a ball valve.
- They are leak-proof; they open and close rapidly, and they feature multi-way design flexibility.
Disadvantages of Ball Valves
- Ball valves are not ideal for permanent throttling.
- In residual fluids, the particles collide with and adhere to the surfaces. This may cause leakage, abrasion, and other issues.
Butterfly Valves
Butterfly valves are basic yet extremely flexible. Butterfly valves, like ball valves, are quarter-turn-driven valves that are widely utilised in a variety of industries and applications. Its quarter-turn element guarantees that the valve operates quickly.
The butterfly disc permits aerodynamic flow around it when it is open. Because there are no voids within their bodies where solid particles can settle, butterfly valves are excellent for regulating flow and can handle slurries or fluids containing suspended solids.
Applications of Butterfly Valves
Butterfly valves are frequently employed in water and air applications, as well as in large diameter pipes.
Advantages and Disadvantages of Butterfly Valves
Advantages of Butterfly Valves
- Butterfly valves are highly precise, making them useful in industrial applications.
- They are incredibly dependable and require little maintenance.
- They have the power to control flow.
- They may be placed or withdrawn without disrupting the pipe system.
Disadvantages of Butterfly Valves
- Butterfly valves do not have tight cut-offs.
- Butterfly valves do not have tight cut-offs. Regardless of the setting, this may result in a pressure switch across the valve.
Globe Valves
In pipelines, globe valves are typically employed to control the flow of more viscous substances such as oil. They are appropriate for both on/off operations and flow rate control. Flow rate control in this sort of valve is regulated by the distance between the lift plug and the valve seat. It is crucial to note that globe valves have a higher pressure drop than many other types of valves due to their S-shaped channel.
Applications of Globe Valves
Global valves are generally used for throttling. They can be thought of as general-purpose flow control valves utilised in high-temperature settings.
Advantages and Disadvantages of Globe Valves
Advantages of Globe Valves
- Globe valves are throttling, but the full-closing behavior is satisfactory.
- The period between opening and closing is reduced.
- The body ring seating surface method is simplified.
- They can be used as a check and stop valves.
- They have a positive shut-off.
Disadvantages of Globe Valves
- Greater pressure loss
- To close under high pressure, globe valves require more effort or an actuator with high torque.
Control Valve Symbols
Needle Valves
Needle valves are used to make relatively precise adjustments in the regulation or control of flow amount. They have a tapered, long, needle-like valve stem that serves as the valve’s control mechanism.
Applications of Needle Valves
They are widely used in various industrial areas, including pressure pump governors, autonomous combustion systems, and instrumentation control.
Advantages and Disadvantages of Needle Valves
Advantages of Needle Valves
- The flow control at a low rate is quite precise.
- Needle valves are more compact and can be utilised for throttling.
- Flow rates can be precisely adjusted.
- Needle valves are utilised as bleed valves in hot water heating systems. These valves are readily shut off.
Disadvantages of Needle Valves
- Because of the significant limitation of the fluid flow, pressure loss is high in needle valves.
- Because of the tiny passage flow between the seat and needle, this valve is utilised for low flow rates.
- If the fluid contains suspended particulates, the seat and needle may be damaged.
- Examining the handle position will not tell us whether the valve is open or closed.
Check Valves
Check valves are valves used in pipe systems to prevent backflow. The pressure of the fluid passing through them activates them. That example, as the fluid flows in one direction, the pressure compels the valve to open and enable the fluid to pass through. When the flow is reversed, however, the valve automatically closes. Back pressure, a spring, a check mechanism, or a combination of all of these are used to close the door.
Applications of Check Valves
- Check valves are utilised in a wide range of markets and applications due to their simple design and diverse material possibilities.
- They aid in the prevention of backflow and the maintenance of pressure.
- Check valves are widely found in industries such as refining, petrochemical, chemical, and so on, oilfield production, water, steam, refining petrol, and viscous fluids, as well as waste-water management systems and manufacturing.
Advantages and Disadvantages of Check Valves
Advantages of Check Valves
- Check valves prevent backflow
- They can sustain pressure
- Check valves serve as backup system
Disadvantages of Check Valves
- They cannot be utilised with pulsing systems.
- The closing element may collide, resulting in damage and excessive wear.