Types of Valves: Application, Working, Design & Methods
What is Valve?
Types of Valve: Application, Working, Design & Methods :- Valves are referred to as those devices which are found controlling work, regulating or directly flowing within a particular system or a process. These mostly feature a range of characteristics which helps in order to define an ideal application. Whereas, if there is a need to control the flow then it must be provided with safety with a system that includes the piping liquids, solids, gasses or anything within it that are likely to be stainless steel valves available to help.
These valves are actually of various uses and also perform several functions which are mentioned below:
- Proper functioning in starting or stopping a flow based on the valve state.
- Consistent regulating of flow and pressure within the piping system.
- It has a major role in controlling the direction of flow within a piping system
- Throttling flow rates within a piping system
- Helps in Improving the safety through relieving pressure or vacuum in a piping system
Categories and Methods of Valve Opening
By now we all are well known with the functions of valves now let’s understand what all are the methods of opening and closing a valve which does not impact the performance but on the other hand also determines the amount of control which you have over the flow and how quickly the valve operates.
Most of the valves are fit into the below mentioned categories:
1. Multi-Turn Valves
These valves are thought like a screw or piston. Crank the handle and the plug, plate, membrane, or other controlling obstruction which moves into the path of the pipe blocking access. It also depends on the valve which can have a higher or lower differentials that allows you in opening or closing them at varying speeds.
2. Quarter Turn Valves
Quarter-turn valves are the types of valves which offer a complete range of motion in a 90-degree turn of the handle. This is the condition which makes it an ideal one for situations where the precision is not that important as compared to the rapid action and easy opening or closing.
The top of the mechanical motion includes a valve which is also considered as the method of actuation. Also in most of the cases the valves fall into one amongst these categories.
3. Manual Valves
As clearly predicted by the name, these are mostly the valves which are adjusted by hand. These are the valves which use hand wheels, hand levels, gear wheels or chains to actuate.
4. Actuated Valves
These types of valves are usually connected to the electric motors, air or pneumatic systems, hydraulic systems or solenoids. These valves help in allowing the remote control and automation for high-accuracy or large-scale applications.
5. Automatic Valves
These are some valves which get activated only when there specific flow condition is met. For instance it includes check valves closing during the backflow or pressure release valves that gets activates whenever an over-pressure condition is detected.
Types of Valves
Valves are found in a very wide range with various characteristics, standards and groupings that help in giving you an idea about their applications and the expected performance. The designing of the valve is one of the most basic way in order to sort the huge range of valves which is available and also finds a good fit for a project or process.
Some of the most common types of valves are mentioned below along with their applications:
1. Rotary Valve: ( Types of Valves )
Rotary Valve : These valves are also referred to as quarter turn valves that mostly relies on the rotary motion of the flow obstructer. In maximum cases the rotation is limited to an angle of 90 degrees which makes it one quarter-turn, whereas, there are various other valves which can operate by the help of a larger degree of rotation that can have more than 2 positions in the regular operation.
Valves which are truly quarter-turn are found closing completely at an angle of 0˚ and completely opening at an angle of 90˚. Ball valves, plug valves, and butterfly valves are some examples of quarter- turn valves.
2. Linear Valve: ( Types of Valves )
There are 2 different types of linear valves first is multi-turn and the other is axial. These two valves are found relying on the linear motion of the flow obstructer, whereas they are quite different in terms of construction and operation.
3. Multi-Turn Rising Stem Valve: ( Types of Valves )
Multi-turn rising stem valves are those valves which move the obstructer by rotating a threaded rod also referred as stem which can be attached to the obstructer. These types of valve are mostly used for flow control applications.
4. Axial Valve: ( Types of Valves )
Axial valves are those types of valves which use pneumatic or electro-magnetic force in order to slide the obstructer along the axis. Coaxial valves angle seat valves are some of the examples of axial valves. These are the valves which are found acting fast and only used for an on/off process.
5. Actuated Valve: ( Types of Valves )
A actuated valve is referred to as a component of a piping system which is mostly used in controlling the flow of the media through the system. This control is developed by manipulation some different types of obstructer within the valve. Actuated valves are those which use mechanical devices known as actuators that operate the valve by the help of a power source like the compressed air or electricity.
Almost all the actuated valves are available in a manually operated version or in an actuated valve accompanied with a manual override. The most popular types of automated valves fall in one amongst these three main categories which are linear, rotary and self-actuated.
6. Ball Valve: ( Types of Valves )
These are referred to as those valves which are predominantly equipped with quick-acting 90-degree turning handles. These are the valves which use a ball in order to control the flow and to also provide an easy on-off control. It is usually accepted by most of the operators to be faster and easier in order to operate as compared to the gate valves.
7. Butterfly Valve: ( Types of Valves )
The butterfly valve is designed in a very compact way with a quick-acting rotary motion valve which is quite ideal for tight spaces. Butterfly valve bodies are found in various configurations.
8. Gate Valve: ( Types of Valves )
A gate valve is referred to as one of the most common type of valves which uses a linear motion in order to start or stop the flow. These valves are mostly not used in the flow regulation process rather are used in the completely open or closed positions.
9. Knife Gate Valve: ( Types of Valves )
These are referred to as those valves which are used for controlling the flow of media which containing solids, the knife gate valve features a quite thin gate which is controlled through the linear action that cuts through the materials and creates a seal. These valves are not that much suited for high-pressure implementations while these valves are considered ideal for the use with grease, oils, paper pulp, slurry and wastewater which might obstruct the operations of the other valve types.
10. Globe Valve: ( Types of Valves )
Globe valves are referred to as those valves which are typically applied in modulating control operations. These are available in three body types T-body, Y-Pattern, and angle body.
11. Needle Valve: ( Types of Valves )
Needle valves are mostly used in the small diameter piping systems where fine and accurate flow control is needed. The needle valves got its name from the point on a conical disc which is used within it.
12. Pinch Valve: ( Types of Valves )
Pinch Valve : These valves are mostly used for handling solid materials, slurries and liquids with suspended solids. These valves are found using a linear motion and also feature an internal sleeve to isolate the media.
Common Functional Designation And Design Types
Isolation Valves:– Ball Valve, Butterfly Valve, Diaphragm Valve, gate Valve, Pinch Valve, piston and plug valves
Regulatory Valves:– Ball Valve, Butterfly Valve, Diaphragm Valve, Globe Valve, Needle Valve, Pinch Valve and Plug Valves
Safety Relief Valves:– Designed as pressure releasing and vacuum relief valves
Non-Returnable Valves:– Swing check and lift check valves
Special Purpose Valves:– Mostly featured as multi-port, float valve, foot, knife gate valve and line blind valves
Sizing Of Valves
Valves might be a very small part of any piping process or system with respect to space which is often a substantial portion of the design and build budget. It is found that they have a quite vital impact at the long-term costs and also on the overall performance of the system. Selecting a correct valve size is quite essential in both optimizing costs which ensures safety, accuracy and reliability in operations. The first and the foremost thing which is kept in consideration is the overall size of the valve, in terms of physical dimensions and also in terms of the internal size and flow rates.
Selecting a valve which does not fit in properly in required space can result in additional costs. Choosing a valve that does not provide the ideal flow rate can lead to an inaccurate flow which at least controls the complete system failure. In case the valve is too small, it can cause a reduced downstream flow by creating a back-pressure upstream. In case the valve is too large it can control the flow which can be reduced drastically and further can move from fully opened or fully closed.
While selecting an accurate size, one must consider both the connector diameters accompanied with the overall flow rate of the valve which should be compared according to your needs. There are some valves which offer an excellent flow whereas the others constrict flow and increase the pressure which means that sometimes you should install a larger valve in order to adjust the flow than the adapter diameter alone might imply.
Valve End Connections
Just considering the size and design is not important, it is also important to consider the valve end connections. So, below is discussed a valve end connection about which one must know:
Common Valve End Types:
The implication of such valve end connection is due to the end connection compatible with the piping. At the same time there is also a functional characteristic to the common end type which might make one valve more suited to the requirement as compared to the others.
The common valve end connections includes some more varieties which needs to be understood:
- Screwed or Threaded:- Mostly used in the connections of an instrument or sample points
- Flanged:- One of the most common ends for piping use
- Butt Welded:- Widely used in high-pressure or high-temperature operations
- Socket Welded:- Highly used in small bore piping where threaded connections are not permitted
- Wafer and Lug:- It is commonly used for compact valves installed in systems with limited space
Importance Of Selecting The Valve Material
Depending on the type of use the material with which the valves are build is a critical aspect which ensures the safe operation and reduces the maintenance and replacement cost during the entire life of your operation.
It is commonly known that the valves made of stainless steel are excellent options in a range of processing environment which also includes the corrosive media like the chemicals, saltwater, and acids with complete sanitation standards and processes by using a quite high pressure or high temperature.
Other than this selecting a correct body material should be evaluated for the chemical compatibility which is of utmost importance. In case there are elastomers present in your valve there should be a complete evaluation for its chemical compatibility as well as the limitations of pressure and temperature.
Selecting a standard of the valve is also important but for that you might need to find that the valve must adhere to the particular standards in order to meet the regulatory requirements for safety, sanitation and other concerns. There are various standard organizations and potential regulations amongst which some common general standard organizations include:
- CSA Group (CSA)
- The American Society of Mechanical Engineers (ASME)
- The American National Standards Institute (ANSI)
- The Manufacturers Standardization Society (MSS)
- The International Organization for Standardization (ISO)
- The Public Health and Safety Organization (NSF)
- NACE International (NACE)
- The American Petroleum Institute (API)