Back pressure flap valve arrangement and the use thereof

1. Back pressure flap valve arrangement comprising a housing having an inlet opening and an outlet opening adapted for connection of the housing to a ducting, and at least one side wall extending along a flow direction through the housing from the inlet opening to the outlet opening, the arrangement further comprising

a flap which is pivotably hinged about a shaft thereby being movable between an open position and a closed position, said shaft extending transverse the flow direction, wherein

an arrangement further comprises at least one locking device being fixedly mounted to the side wall and comprising a locking pin and a stopping member,

said locking pin being movable between a retracted position and a locking position, and being biased towards said locking position, and

the stopping member being movable from a stop position in which the stopping member is adapted to hold the locking pin in its retracted position, to a release position by the flap acting on the stopping member in case of a back pressure, thereby allowing the locking pin to move into the locking position in which the locking pin maintains the flap in the closed position wherein the stopping member comprises a shoulder arranged to engage the locking pin when the locking pin is held in its retracted position.

2. Back pressure flap valve arrangement according to claim 1 , wherein the ducting comprises a flexible sealing arranged in a position between an inlet opening of the ducting and the flap, and wherein the flexible sealing must be at least partly compressed by the pivoting of the flap for the flap to be able to act on the stopping member.

3. Back pressure flap valve arrangement according to claim 2 , wherein a radial gap is formed between the flexible sealing and the inlet opening of the ducting.

4. Back pressure flap valve arrangement according to claim 1 , wherein the stopping member is movable from the stop position to the release position by the stopping member being arranged to pivot around a pivot, said pivot having a longitudinal extension essentially in parallel with the surface extension of the flap as seen in a position when the flap has pivoted to its closed position in case of a back pressure.

5. Back pressure flap valve arrangement according to claim 1 , wherein the stopping member comprises a stop face having a surface extension essentially in parallel with the surface extension of the flap as seen in a position when the flap has pivoted to its closed position, and wherein the flap, in case of a back pressure, is arranged to act on said stop face thereby moving the stopping member from its stop position to its release position.

6. Back pressure flap valve arrangement according to claim 1 , wherein the flap comprises at a stiffener, and wherein the locking pin is adapted to abut said stiffener in a condition when the flap has been pivoted to its closed position.

7. Back pressure flap valve arrangement according to claim 1 , wherein the locking device further comprises a base plate via which the locking device is fixedly mounted to a side wall of the housing, wherein the locking pin is arranged to extend from a first side of the base plate, via a through hole in the base plate, to a second side of the base plate, and wherein the locking pin is biased towards the locking position by an elastic member being supported by the portion of the locking pin extending on the second side of the base plate.

8. Back pressure flap valve arrangement according to claim 7 , wherein the locking device further comprises a resetting member, said resetting member comprising a resetting pin extending from the first side of the base plate, via a through hole in the base plate, to the second side of the base plate, and whereby the stopping member is arranged to be moved from its release position to its stop position by pushing the resetting member towards the stopping member.

9. Back pressure flap valve arrangement according to claim 8 , wherein the resetting member is biased towards the first side of the base plate.

10. Back pressure flap valve arrangement according to claim 1 , wherein the locking pin is arranged to be set from the locking position to the retracted position by pulling the locking pin, thereby overcoming the biasing, and while pulling the locking pin, moving the stopping member from its release position to its stop position.

11. Back pressure flap valve arrangement according to claim 1 , wherein the shaft is rotatably suspended in two opposing side walls of the housing, and wherein the suspension is made via two long holes arranged in the respective side walls.

12. Back pressure flap valve arrangement according to claim 1 , wherein the flap is further pivotably hinged along a pivot extending in parallel with the shaft, said pivot being arranged to extend across the surface extension of the flap.

13. Use of a back pressure flap valve arrangement according to claim 1 in a ducting intended to conduct a dust or particulate laden gas flow.