Pneumatic globe valve (1)

♦ Standard

♦ Dimensions

♦ Constitution

International electrician committee IEC to regulating valve (overseas name control valve Control Valve) the definition is: "In the commercial run control system the terminal part which forms by the power operation installment, it including a valve body part, the interior has a change process fluid module, the valve body part connects with or many implementing agencies. The implementing agency uses for the signal which responds the control part to send ".

Obviously, the regulating valve is composed by the implementing agency and the valve body part two parts, namely regulating valve = implementing agency + valve body part

Among them, the implementing agency is the regulating valve impetus equipment, it has the corresponding thrust force according to the signal pressure size, causes the throwout lever to have the corresponding displacement, thus drives the regulating valve the valve core movement; The valve body part is the regulating valve adjustment part, it directly with the medium contact, by the implementing agency throwout lever displacement, changes the regulating valve the throttle area, achieves the adjustment the goal.

The regulating valve different mainly divides into the air operated regulating valve, the electrically operated regulating valve, the fluid according to its energy way moves the regulating valve three big kinds. Their difference lies in on the implementing agency which matches. Former matches is the air operated implementing agency (must add locator), the middle one kind matches is the electrically operated implementing agency, latter matches is the fluid moves the implementing agency. (For details sees this book implementing agency about implementing agency to be partial)

♦ Accessories

1. The locator (for details sees this book 119 page)

The locator enhances one of regulating valve performance important methods. The locator use closed loop principle, feeds back the output valve position compares with the input value, namely the valve position signal directly compares with the valve position. When does not bring the locator, the valve position signal is the aerodynamic pressure. It affects on the diaphragm or the piston has the thrust force, axial makes the strength with the spring tension and the valve to be balanced. Therefore, in this strength certain situation, or the friction force, and so on does not change, inevitably causes the spring tension change, but causes the travelling schedule to change, when namely does not bring the locator, the valve position signal pressure is not the direct valve position comparison, but is the strength balance, therefore precision low, does not change in a big way, the valve position change is also big. Therefore, selects the locator to be able greatly to enhance the valve the precision, imultaneously, because is mad source pressure high. Also can enhance the valve to permit with the differential pressure, moreover also has speeds up the valve movement, change function and so on function way, change discharge characteristic.

Locator main function:

(1) it may completely be mad the source pressure delivers the regulating valve in the implementing agency membrane room, causes to be mad the source pressure obtains the full use, to this enhanced the implementing agency output strength, the corresponding threshold energy shuts off a bigger differential pressure.

(2) because is depends on the position to feed back, when the friction force is bigger, then produces in a big way returns to the difference, the locator then may change the discharge pressure to cause the valve to decide in the corresponding position,
"the locator ' ' its comes, is this truth. Therefore, it also has enhances the valve the position precision function.

(3) the locator delivers the entire gas source the membrane room, when the membrane chamber pressure causes the valve movement and walks when the corresponding position, was mad the source is cut, the valve then stabilizes in some position, is said, the valve air feed speed is quick, the valve movement speed speeds up.

(4) the electrical switch function, can use electricity the signal to control the air operated valve.

2. The solenoid valve (for details sees this book 117 page)
The solenoid valve uses for to cut is mad the signal, causes the main valve either Guan orkai. When chooses the solenoid valve, but also must consider solenoid valve signal, whether needs to guard against explosions, to lose when the electricity the main valve switch position.
3. Limit switch
4. The manual operation organization (for details sees this book 128 page)
5. The pressure relief valve (for details sees this book 116 page)
Docking is angry the source pressure air operated measuring appliance and the electrical valve locator, the switch, may select the pressure relief valve. It both may filter the air, and may adjust the solar terms source pressure the size, by obtains the gas source pressure value which needs.

♦ Model establishment