PAV Pneumatc control valve:

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 "setpoint" to a "process variable" whose value is provided by sensors that monitor changes in such conditions.The opening or closing of control valves is usually done automatically by electrical, hydraulic or pneumatic actuators. Positioners are used to control the opening or closing of the actuator based on electric, or pneumatic signals. These control signals, traditionally based on 3-15psi (0.2-1.0bar), more common now are 4-20mA signals for industry, 0-10V for HVAC systems, and the introduction of "Smart" systems, HART, Fieldbus Foundation, and Profibus being the more common protocols.A control valve consists of three main parts in which each part exist in several types and designs:Valve's actuatorValve's positionerValve's body
Control valve is made up of pneumatic multi spring diaphragm actuator and lower flow resistance straight single seat valve(sleeve). The single valve is connected directly with its guilding structure on the cap; with its corn is ram structure, which is smaller and lighter than normal single seat valve and its flux is bigger than normal sleeve valve. It is widely applied in industry process and automatic controlling system.    
Features:Body type: Straight line single seat (sleeve) foundry valve S style
D N: DN10~300mmPN:   PN1.6    4.0    6.4  10.0MPa Connecting way: Flange style JB78-59 JB/T79.2-94 concave style Material : HT200 ZG230—450 ZG1Cr18Ni9Ti ZG0Cr18Ni12M02Ti
Back cover: Normal temperature -20~+200℃ Heat elimination type -40~+450℃
Packing: V-pattern PTFE, soft graphite, stainless steel bellows