Double Cone / Flap valves are used for controlled feeding as well as achieving air lock sealing. These valves consist of two independent Cone / Flap valves mounted one upon other with their opening and closing alternated and synchronized to ensure that only one valve opens at a time.

DEMECH manufacture these valves to suit the opening sizes and required through-put rate. The through-put of these valves depend on the holding volume of the upper valve chamber and the rate of operations.

These are very slow operating valves as the operation cycle rate does not usually exceed beyond 6 cycles per minutes. Thus these valves have a batch feeding pattern rather than continuous feeding.

Selection of Cone or Flap depends on the characteristics of material to be handled and system requirement like pressure sealing. Cone valve has a better sealing than the flap valve. However, in smaller size valves, the cone can act as an obstruction in the flow resulting in clogging of the small opening. The cone valves usually have round opening whereas the flap valves can have square.

Double Flap/Cone Valves are used for extracting bulk material from collection vessels which are maintained at a pressure different than the outside. Typical locations include below ESP hoppers & Bag House hoppers etc., where the dust collection chambers are at a negative pressure. The valves can handle fine dusty or grainy material like cement, crushed ore, sugar, minerals, grains, plastics, dust, fly ash, flour, gypsum, lime, coffee, cereals, pharmaceuticals etc.

Technical Details

  1. DEMECH has supplied flap valves having inlet size from 200 to 500 mm square and cone valves upto of 400 mm diameter have been supplied.
  2. The valves need power to open but are closed naturally by counter-weights.
  3. The valves are fabricated from mild steel plates with access cover to inspect and attend to the cone or flap. Due to low and controlled speed, wear due to abrasive material is minimal. The entry and exit of chamber can be provided with liners for longer life.
  4. Cone and seat are casted in suitable wear resistant material to take care of abrasion.
  5. The flaps are fabricated either with replaceable liners of hard material or they are manufactured from hard plates like Sailhard or Hardox.
  6. The valves are either driven by electric motors or pneumatic / hydraulic cylinders. To achieve the alternate and sequential operation, the motor driven valves have specially custom designed cam arrangement and the cylinder operated valves have a sequential timer based controller.

DEMECH valves offer the following benefits –

  1. Custom made design of valves ensure total satisfaction of customers’ requirements.
  2. Valves are designed to operate at low speed resulting in longer life and reliability of material handling rates.
  3. Optimum opening at valve entry, thus minimizing blockages.
  4. Heavy shaft diameters minimizing deflection.
  5. Outboard bearings for non-contamination.
  6. Sealing by using gland packing.
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