The BV-Butterfly Valve has a flanged construction which eliminates the need for pipe unions. 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. FEATURES For most fuel gases and air 400° maximum temerature Double bearing shaft - positive alignmentViton "O" Ring sealed shaft Thumb screw lock - holds disc positionAdjustable limit stop - both high and low flow Disc position indicator on name plate Cast iron body, steel discLarge, easy-grip dial handle 1/8'' NPT tap for pressureSimple field conversion from manual to automatic operations CAPACITY TABLE Model No. Pipe Size NPT (in.) Capacity Air CFH 1/2" W.C. Drop 1" W.C. Drop 2" W.C. Drop 6 BV 3/4'' 600 900 1,300 8 BV1'' 7501,100 1,500 10 BV 1-1/4'' 1,800 2,500 3,600 12 BV 1-1/2'' 2,000 2,800 3,900 16 BV 2'' 3,700 5,200 7,300 20 BV 2-1/2'' 6,100 8,600 12,200 24 BV 3'' 9,300 13,100 18,500 32 BV 4'' 18,000 25,000 36,000 48 BV 6'' 40,000 55,000 80,000