The Stanelle overpressure and vacuum flap type SDAK is a safety organ for silos which are filled pneumatically. Overpressure as well as vacuum - the latter arising from exhaust fans or through rat hole collapses - can be equalized because of the combined design of the pressure flaps. The optimum protection of the silo is guaranteed through the maintenance-free construction of the SDAK flaps.
The weighted, ball bearing supported flaps are opened through the outside, respectively to the inside pressure of the silos. In the unopened position, the rubber-coated flap discs are dust tight. With a negative pressure of more than 5 mbar the negative pressure flap is opened through the outside pressure. Outside air can stream into the silo for pressure equalization. When overpressure occurs in the silo interior, the flap, with an adjustable weight, opens. The excessive pressure can be neutralized via the flap opening. The special design guarantees that the actuating pressure does not increase excessively and the outlet opening can respond fully.