FLOW CONTROL VALVES: DIAGRAM, TYPES, WORKING & USES
#1 Butterfly Valve
The butterfly valve has a circular disc that can be rotated through one complete revolution. The circular disc has a diameter equal to that of a pipe.
The valve is connected across both faces by two pipes with flanges. A circular disc is made to rotate around an axis passing through the vertical diameter of the disc. This type of flow control valve is used for controlling moderate flow.
#6 Pressure Compensated Flow Valve
The pressure compensation flow valve provides a uniform volume flow rate independent of the pressure drop across the valve. On the other hand, the non-pressure-compensated valves have a variable flow rate that changes as the pressure in the valve fluctuates.
#7 Pinch Valve
These are types of flow control valves, which are inexpensive and are used in almost all industries. It consists of flexible elements such as rubber tubes for sealing purposes. They are designed to give a tight seal around trapped solids with their flexibility, these rubber tubes are the moistened part in a pinch valve.
Pinch valves are perfect for liquids that contain large amounts of suspended solids. The valve body acts as a built-in actuator, reducing the need for expensive operators such as pneumatic, hydraulic, or electric operators.
#8 Globe Valve
These are considered valuable for starting, stopping, and regulating the flow in a linear motion. Globe valves are used for throttling applications because the disc of the valve can be completely removed from the flowline and are also capable of closing the flowline completely.
Unlike the other types that are straight-through valves, these valves produce slightly high-pressure drops. The closure in a globe valve is opened by means of a plug that covers a flat bottom and is then lowered onto a horizontal seat in the center of this valve. The plug in the globe valve lifts when the user opens it, and this allows the fluid to flow.
#9 Diaphragm Valve
These valves are built to handle conditions that require erosive, corrosive, and dirty services. It consists of a flexible disc that reaches the top of the valve body along with the seat to form a seal. These are used to control the opening or closing of the valve.
These valves work by an elastomeric diaphragm in the valve body, rather than an elastomeric liner, which is attached to a compressor to isolate the closure element from the fluid flow. This gives the advantage that they feature a leak-proof seal and are easy to maintain.
#10 Ball Valve
Ball valves are commonly used in a variety of industries because of their low cost, durability, and excellent closing capability. These are similar to a butterfly valve, they are not suitable for flow control applications as they require high accuracy and control.
This is because a high level of torque is required to open and close a ball valve which prevents an operator from making fine adjustments. The ball valve is used for filling a tank with reasonable accuracy. A trunnion or V-port ball valve design is usually the best type.