Air admittance valve for sanitary waste pipe system

摘要

The invention relates to a valve for admitting atmospheric air into the waste pipe system in response to a pressure reduction in the system and for preventing discharge of contaminated air from the waste pipe system to the atmosphere. The valve consists of a valve body having at least two air inlet openings (30) in connection with the atmospheric air, each of the openings (30) alternating with a passage (14) towards the waste pipe system, said openings and passages (14) being equally distributed within the valve housing when considering a cross sectional view in a horizontal plane about the valve seat level (H). The valve member (34) resting, in normal closed position, on a the valve seat (24) separating said openings (30) from said passages (14) and having a substantially butterfly shaped sealing surface in case of a valve embodiment having two diametrically opposed openings (30) situated perpendicular to respectively two diametrically opposed passages (14)