Double Flap Valves
Double Flap Valves are a type of airlock valve commonly used in industrial applications as a component in bulk material handling applications. Double flap valves are primarily used to discharge chunky or fibrous, bulk materials from hoppers, bins, and cyclones operating under positive or negative pressure. Double flap valves are used to discharge a flow of material while at the same time serving as an airlock transition point to preserve the pressure differential above and below the valve. This type of material handling valve is ideal for use with bulky or abrasive materials that would tend to jam or damage a rotary feeder.
Operation
Double flap valves have two trap-door flap plates which open and close on an alternating cycle. The top gate opens to allow collected material to drop through onto the bottom gate. The top gate then re-closes to prevent air leakage above the valve. The bottom gate then opens to allow material to pass completely through the valve. The bottom gate then re-closes to prevent air leakage below the valve. This cycle is continuously repeated in order to maintain a steady discharge of material from the valve, while maintaining a positive seal on the system.