VALVES & SWITCHES

What is a Valve ? A valve is a device that regulates the flow of a fluid ( gases,

liquid, fluidized, solids, slurries) by opening, closing, or

partially obstructing various passageways.

Types of Valves:Gate ValveGlobe ValveBall ValvesCheck ValvesButterfly ValveControl Valve

Gate ValveGate Valve are used when a straight line flow of fluid and minimum restriction is desired. When gate valve is wide open, the gate is completely drawn up into the valve body, allowing for pressure and flow through the valve that is consistent with the attached pipe.

Gate Valve Video

Globe ValveThe globe valve derives its name from the globular shape of valve body. They are widely used in industry to regulate fluid flow in both on/off and throttling service. Globe valves are typically two-port valves. Ports are openings in the body for fluid flowing in or out. The two ports may be oriented straight' across from each other on the body, or oriented at an angle such as a 90° angle, called angle globe valves.

Globe Valve Video

Ball ValveThey are widely used in fluid-handling systems for flow control. They provide superior ease of operation and can maintain and regulate high volume, high pressure and high temperature flow. Most ball valves offer rugged construction providing for a long service life, and a comparably low cost. There are three general body styles of ball valves: split body, top entry, and welded.

Ball Valve Video

Check ValveCheck Valves are mechanical valves that permits gases and liquids to flow in only one direction, preventing process flow from reversing. They are classified as one way directional valves. Fluid flow in the desired direction opens the valve, while backflow forces the valve closed.Ball check valves contains a ball that sits freely above the seat, which has only one through hole. The ball has a slightly large diameter than that of the through hole. When the pressure behind the seat exceeds that above the ball, liquid is allowed to flow through the valve. But once the pressure above the ball exceeds the pressure below the seat, the ball returns to rest in the seat, forming a seal that prevents backflow.

Check Valve Video

Butterfly ValveA Butterfly Valve is used for isolating or regulating flow. The Closing mechanism takes the form of a disk. Operation is similar to that of a ball valve, which allows for quick shut off. Butterfly valves are generally lower in cost , lighter in weight and meaning less support is required.

Butterfly Valve Video

Working of Butterfly Valve

Control Valves Control Valves are

valves used to control conditions such as flow, Pressure, Temperature and level by fully or partially opening or closing in response to signals received from controllers that compare a set point to a process variable. Control Valve belongs to the category of Final Control Element.

The Major three elements of Control Valve:

1. Valve Body

2. Actuator

3. Bonnet Assembly

Control Valve AccessoriesPositioner

I/P Converter

Limit Switch

Solenoid Valve

Air Filter Regulator

Pneumatic Lock up system

Solenoid Valve A solenoid valve is an

electromechanical device used for controlling liquid or gas flow. The solenoid valve is controlled by electrical current , which is run through a coil. When the coil is energized, a magnetic field is created, causing a plunger inside the coil to move. Depending on the design of the valve, the plunger will either open or close the valve. When electrical current is removed form the coil, the valve will return to its de-energized state