ASTM A105/A105M – Standard Specification for Carbon Steel Forgings for Piping Applications
ASTM A106- Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service
ASTM A216 WCB/WCC – Standard Specification for Steel Castings, Carbon, Suitable for Fusion Welding, for High-Temperature Service
ASTM A350 LF2 – Standard Specification for general Carbon steel usually supplied in the Normalised, Normalised and Tempered or
Quench and Tempered condition.
ASTM A352 LCB, LCC – Standard Specification for Steel Castings, Ferritic and Martensitic, for Pressure-Containing Parts, Suitable for Low-Temperature Service
||Equivalent Cast Steel
|Moderate, high temp. service
||A216-WCA WCB WCC
|Cold temp. service
Each type of carbon steel valve serves a very distinct purpose. Such valves are used in a number of industries around the world, including water management, chemical processing, and food production. Valves are quite diverse and may be classified into a number of basic types.
Valves can also be classified based on their functions:-
- End connection
- How it operates
- Types of Actuator it used.
Classification of Valves based on end connections:-
- Wafer and Lug end construction
- Screwed or threaded
- Flanged type ends
Classification of Valves based on actuator:-
The last way to classify the valve is, types of the actuator used to transfer the motion to operate the valve. The valve can be operated manually with the help of handwheel, lever, chain or by a gear wheel. An external power source such as an electric motor, air, hydraulic fluid or solenoid is used to operate valve from the control room. Check valve works automatically when subjected to the backflow.
- Solenoid valve
Classification of Valves based on mechanical motion:-
- Linear Motion Valves
- Rotary Motion Valves
- Quarter Turn Valves
Types of Valve, Butterfly Valve, Pressure Relief Valve, Ball Valve, Gate Valve, Check Valve, Globe Valve, Control Valve, Plug Valve, Diaphragm Valve, Needle Valve
Types Of Valves:
- Check Valve:- Check valves are commonly used for the prevention of back flow into a pipeline.
- Plug Valve:- A plug shaped valve that uses a tapered or cylindrical plug to stop or start the flow. Plug valve is Quarter-turn rotary motion Valve. Plug valve can be used in vacuum to high-pressure & temperature applications
- Pressure Relief Valve:- Pressure Relief Valve also known as Pressure Safety Valve are used to protect equipment or piping system during an over pressure event or in the event of vacuum. This valve releases the pressure or vacuum at pre-defined set pressure.
- Gate Valve:- A carbon steel gate valve functions as an on/off valve. The gate or disc located inside the value is raised and then lowered while a handle is turned. Such valves are not ideally suited for regulating flow, and using them in that manner could result in damage to the disc mechanism. Two styles of gate valves are available: rising stem and non-rising stem. Gate valves are used in almost all fluid services such as air, fuel gas, feed water, steam, lube oil, hydrocarbon, and all most any services.
- Knife Valve:- Knife valves are actually similar in nature to gate valves. The main difference is that a knife valve is more compact than a gate valve.
- Butterfly Valve:- Butterfly valve is a quarter-turn rotary motion valve, used to stop, regulate, and start the flow.
- Ball Valve:- Ball valves are typically used as a type of on/off control without incurring a drop in pressure. These types of valves are ideally suited for situations requiring a quick shut-off. A 90-degree turn can complete a shut-off with this valve, as opposed to the multiple turns that would typically be necessary for manual valves.
- Disc Check Valve:- Disc check valves, also called as non-return valves allow the flow to pass through them in only one direction and stop the flow in reverse direction. Because of this unique directional property, disc check valves are essentially used for some critical applications in the steam systems. There are 4 major types:-
- Diaphragm Valve:- In situations in which flow needs to be controlled with the movement of a diaphragm, a diaphragm valve is commonly used.
- Lift Check Valve:- Lift check valves work simply on the principle of gravity.
- Swing Check Valve:- In this kind of check valve, the disc or the closing element swings around a point to which it is hinged.
- Spring loaded Check Valve:- In this kind of check valves, tight shut-off it provided using a spring.
- Globe Valve:- Globe valve is used to stop, start, and regulate the fluid flow. Globe Valves are used in the systems where flow control is required and leak tightness is also necessary. Globe valve provides better shut off as compared to gate valve and it is costlier than gate valve.
- Needle Valve:- Needle valves are similar to a globe valve in design with the biggest difference that is the sharp-pointed conical disc and matching seat. Needle valves are designed to give very accurate control of flow in small diameter piping systems.
- Pinch Valve:- Pinch valves consist of a plastic tube/sleeve which is made up of reinforced elastomers. The sealing/ closing action is achieved by throttling or pinching this sleeve/tube. Pinch valves are best suited for handling slurries and fluids having suspended solids. Pinch valves offer many benefits over the other types of valves. They can be used for handling corrosive fluids as there is no contact between the fluid carried and the actual valve mechanism. Generally, pinch valves are suitable for low pressure applications. When used with abrasive slurries, they should be used as on-off valves; if used for throttling purposes, the sleeve will get worn out.