Patent ID: 6990964

Claim:
An apparatus for regulating the gas/air ratio for a pre-mixing combustion device comprising: a pneumatic regulator, which maintains a ratio of pressure in a gas conduit and pressure in an air conduit constant; a mixing device, which is arranged downstream of the regulator, said mixing device comprising: a mixing chamber, which diverges from its inlet opening in the flow direction in the manner of a venturi nozzle, a nozzle, which is connected to the air conduit and extends into the inlet opening of the mixing chamber, an annular gap, which is connected to the gas conduit and is defined between an edge of the inlet opening of the mixing chamber and the nozzle connected to the air conduit, and a conical member, which is arranged in the air conduit and is moveable in an axial direction relative to the nozzle connected to the air conduit in dependence on a signal from a sensor; and a fan whose speed is controllable, said fan for conveying a gas/air mixture out of the mixing chamber to the combustion device.