Filtering device for removing bacteria from the ventilation air

Claim 2

An air filtering device for removing bacteria from the ventilation air current supplied into rooms to be held under sterile conditions, such as operating theaters in hospitals, laboratories for preparing pharmaceuticals, etc., comprising a ventilation circuit defined by an air supply conduit including a portion limited by an air inlet and a conditioned air outlet, a suspended matter filter in said air supply conduit and a branch disinfection line connected to said air supply conduit on each side of said filter and first and second control valves connected between said air supply conduit and said branch line on each respective sides of said filter, a disinfection device adapted to circulate a disinfectant in said branch line through said filter, said first and second control valves being selectively operable to connect said branch conduit to said air supply conduit.

Claim 3

An air filtering device, according to claim 1, including a gas filter for removing residual disinfectant contained in said air supply conduit downstream of said filter.

Claim 4

An air filtering device for removing bacteria, according to claim 1, wherein said first and second valves are three-way valves.

Claim 5

An air filtering device for removing bacteria, according to claim 3, wherein said disinfection device comprises means for directing a disinfecting liquid into the air stream, and a fan for producing an air stream flow through said branch line and through said suspended matter filter when said first and second valves are set to connect said disinfecting line and the portion of said air supply with said filter together.

Claim 6

An air filtering device, according to claim 3, wherein the disinfection line comprises venting means, and a three-way venting valve connected between said disinfecting line and said venting means permitting venting to the atmosphere.

Claim 7

An air filtering device, according to claim 5, wherein said venting means is located between said disinfecting device and said fan.

Claim 8

An air filtering device for removing bacteria, according to claim 5, including a timing device connected to said first and second control valves, said fan and said disinfecting device and permitting the fOllowing operating positions: a. a position of said first and second control valves in which the inelt and outlet of the air supply control are open, the disinfection equipment is cut off and the vent is closed, so that supplied air flows through the suspended matter filter to the room to be ventilated; b. a position of the valves in which the inlet and outlet of the air supply conduit are closed, the suspended matter filter is connected into the disinfection circuit, the vent is closed, the fan is switched on and the device furnishing the disinfection is in operation, so that only the air contained in the disinfection circuit and entraining the disinfectant is circulated through the suspended matter filter; c. a position of the valves in which the inlet of the air supply conduit is open, the outlet of this conduit is closed, the branch of the disinfection circuit extending from the device furnishing the disinfectant to the inlet side of the filter is shut-off, the device furnishing the disinfectant is out of operation, the vent is open and, in case the vent is located at the pressure side of the fan, the fan is switched on, so that fresh air flows through the suspended matter filter entraining the disinfectant and escapes through the vent.

Claim 9

An air filtering device, according to claim 5, wherein said venting means is lccated between said fan and said suspended matter filter.

Claim 10

An air filtering device, according to claim 8, wherein said venting means is combined with said second control valve and is located downstream of said suspended matter filter.