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Control valves are valves used to control conditions such as flow, pressure, temperature, and liquid level by fully or partially opening or closing in response to signals received from controllers that compare a "set point" to a "process variable" whose value is provided by sensors that monitor changes in such conditions. The opening or closing of control valves is done by means of electrical, hydraulic or pneumatic systems. Positoners are used to control the opening or closing of the actuator based on electric, or pneumatic signals. These control signals, traditionally based on 3-15 psi, more common now are 4-20ma signals for industry, 0-10v for hvac systems, & the introduction of "smart" systems, hart, field bus foundation, & profibus being the more common protocols.The most common and versatile types of control valves are sliding-stem globe and angle valves. Their popularity derives from rugged construction and the many options available that make them suitable for a variety of process applications, including severe service. In automatic flow control valve is formed of a housing defining a valve chamber and a valve body axially displaceable within the valve chamber. The juxtaposed surfaces of the valve chamber and valve body form a flow passageway through the valve and are arranged to avoid any sudden changes in the cross-sectional flow area. The juxtaposed surfaces have a frustoconical shape converging in the direction of flow of a pressurized fluid through the valve. The valve body and the valve chamber cooperate to form a number of separate chambers which receive pressurized fluid for balancing the counteracting forces on the valve for regulating flow through it. The present control valve is directed to an automatic flow control valve, and more particularly, it is concerned with the arrangement of the flow passageway surfaces within the valve for avoiding any sudden changes in cross-sectional area in response to pressure changes within the fluid flowing through the valve for preventing cavitation and vortical flow. Generally, the quantity of fluid flowing through a valve is increased or decreased in direct relationship with the increase or decrease of the square root of the pressure differences in the fluid passing through the valve, that is, the pressure differences in the fluid at the inlet to and the outlet from the valve. However, when the pressure differences within the valve vary upwardly or downwardly, an automatic flow control valve must be able to regulate the resistance within the valve for maintaining a selected flow rate from the valve.
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Featured Suppliers of Automatic Control Valve
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Eagle Poonawalla Industry Ltd. |
| Company Profile : |
Elomatic, pneumatic actuators, electrical actuators, control systems, valve, automation, india, poonawalla, butterfly, ball, plug, valves, accessories, solenoid |
| Products Profile: |
Valves |
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