Air flow in low pressure lines (up to 3 psig) is easily and effectively controlled by the butterfly valve. This may be done manually or automatically by using suitable control equipment. These valves are designed for free flow with minimum air pressure drop. As they are not intended for tight shut-off, slight leakage (less than 2%) may occur in the closed position.
In most applications it is necessary to maintain the rate of firing above the backfire point of the burners. Manual butterfly valves are furnished with an adjustable minimum stop. After once setting this stop, the operator can turn the air up and down without danger of inadvertently going too low. Models are available for electric or pneumatic actuator operation (see Bulletins 1302 and 1303).
Features and Benefits
- For most fuel gases and air.
- 400°F maximum temperature.
- Double bearing shaft – positive alignment.
- Viton O Ring sealed shaft.
- Thumb screw lock – holds disc position.
- Adjustable limit stop – both high and low flow.
- Disc position indicator on name plate.
- Cast iron body, steel disc.
- Large, easy-grip dial handle.
- 1/8 NPT tap for pressure.
- Simple field conversion from manual to automatic operations.