Types of Valve

CONTENT
what is valve?
valves function?
types of valves?

1. FOUNDATION UNIVERSITY RAWALPINDI CAMPUS HARIS ALI

2. TYPES OF V ALVE

3. What is valve ? Valve Functions? Valve types ? C ontent

4. What is valve? A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways.

5. Valve Functions Stopping and starting fluid flow. Varying the amount of fluid flow. Controlling the direction of fluid flow. Regulating downstream system or process pressure. Relieving component or piping over pressure

6. Globe valve Gate valve Ball valve Needle valve Butterfly valve Diaphragm valve Check valve Safety valve Valve T ypes

7. Globe Valve A Globe valves is a linear motion valve and are primarily designed to stop, start and regulate flow. The flow pattern through a globe valve involves changes in direction, resulting in greater resistance to flow, causing high pressure drop. The globe valve is an excellent valve to use for on-off service, but is highly suited for frequent cycling and control of fluids anywhere in amount or volume between the open and closed positions

8. Gate Valve Gate valve is a sliding type of valve. The gate slides down to close the valve. In fully open conditions, the flow area is equal to the area of the pipe and hence, there is negligible pressure drop across the valve. Gate valves operate slowly.

9. Ball Valve Advantages Maintains and regulates high volume, high pressure, and high temp flow . No lubrication requirements. Time of valve operation is minimized. Can handle fluids with suspended solids. Disadvantages Have relatively poor throttling characteristics. Difficult to clean, leads to contamination . A ball valve is a rotational motion valve that uses a ball-shaped disk to stop or start fluid flow.

10. Needle valve A needle valve is a type of valve having a small port and a threaded, needle-shaped plunger. Needle valves are usually used in flow-metering applications, especially when a constant, calibrated, low flow rate must be maintained for some time.

11. Butterfly Valves Butterfly valve is a simple system which has a rotating thin disc rotating across the flow. Quick opening valve. Pressure drop across a butterfly valve is small. Used with chemical or corrosive media . A butterfly valve can be operated manually and automatically. The effect on the fluid by the closing and opening of the disc is shown.

12. Diaphragm Valves Diaphragm valves get their name from a flexible disc which comes into contact with a seat at the top of the valve body to form a seal. The valve body may be constructed from plastic, metal, wood or other materials depending on the intended use . Advantages Valve construction prevents leakage of the fluid without the use of a gland seal ( packing) Disadvantages These types of valves are generally not suited for very high temperature fluids and are mainly used on liquid systems.

13. Check Valve The check valves are non-return valves. These valves allow the fluid to flow only in one direction. Check valve will be open only when the fluid is flowing in the allowed direction. If the fluid flows in the opposite direction, the pressure in the opposite direction closes the valve automatically. These valves are important for preventing backflow to systems.

14. Safety valve S afety valve is also called a pressure relief valve (PRV), which automatically releases a substance from a boiler, pressure vessel, or other system, when the pressure or temperature exceeds to reference value/limits . The primary purpose of a safety valve is the protection of life, property and environment . A safety valve is not a process valve or pressure regulator and should not be misused as such. It should have to operate for one purpose only: overpressure protection.