Vacuum interface valve

Abstract

A vacuum interface valve is used in a vacuum sewerage system in which sewage is transported under the influence of vacuum to a wastewater treatment station or a public main sewer. The vacuum interface valve includes a casing having an inlet, an outlet and a valve seat, a valve member which is linearly movable between a position engageable with the valve seat and a position away from the valve seat, an element for urging the valve member into engagement with the valve seat, and a vacuum device for lifting the valve member under the action of a vacuum to cause the valve member to disengage from the valve seat. The inner wall of the casing is bulged outwardly from the vicinity of the valve seat in a direction substantially perpendicular to an axis of the valve member, and a space is defined in the vicinity of the valve seat in the casing so that foreign matters are not caught between the inner wall of the casing and the valve member.

Dependencies are inferred from the claim text.