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 in order to protect the water traps in the system and to prevent discharge of contaminated air from the waste pipe system to the atmosphere. The valve consists of a valve body (10) having at least two air inlet openings (30) in communication 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 (20) 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 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). In order to obtain a balanced air distribution within the valve body, the total surface of the air flow passage through the open valve function elements (24, 34, 64) should be substantially equal to the total surface of the air inlet openings (30).