Patent ID: 6397874
Filing Date: 2002-06-04
Classification: E03F,F16K,Y10T

Abstract:
A vacuum sewage system comprising:a downstream vacuum source for creating a pressure vacuum in said vacuum sewage system; and at least one dual backflow check valve apparatus, said dual backflow check valve apparatus comprising: a valve body attached to said downstream vacuum source, said valve body defining a branch conduit having an upstream portion and a downstream portion, and a service conduit extending from said branch conduit from a location between the upstream portion and the downstream portion of said branch conduit and forming an acute angle with the upstream portion of said branch conduit, said branch conduit and said service conduit each having an internal bore, the internal bores of said branch conduit and said service conduit being in fluid communication and forming a service inlet; a branch valve seat encircling the upstream portion of said branch conduit; a service valve seat encircling said service inlet formed between the internal bores of said service conduit and said branch conduit; and a valve flap pivotally mounted inside said valve body, said valve flap having a first position wherein said valve flap seatingly engages said service valve seat and having a second position wherein said valve flap seatingly engages said branch valve seat; wherein said valve flap pivots to said first position and prevents backflow into said service conduit when fluid flows from the upstream portion of said branch conduit to the downstream portion of said branch conduit, and said valve flap pivots to said second position and prevents backflow into the upstream portion of said branch conduit when fluid flows from said service conduit to the downstream portion of said branch conduit.