Patent ID: 8182702

Claim:
In a gas pipeline, the improvement comprising a strainer for filtering a gaseous flow stream passing therethrough, while reducing vortex shedding and related noise and vibration, which comprises: a) a generally conical elongated member defining a generally longitudinal axis, and having an opening at one end and a closed end at the opposite end, said elongated member having a plurality of rows of apertures located between said opening and said closed end, said apertures of each row being of dimension generally equal to the dimension of the remaining apertures in said row and being located in a plane generally perpendicular to said longitudinal axis, said plurality of rows of apertures including: i) a first row of apertures defining a first series of apertures of predetermined dimension; ii) a second row of apertures located adjacent said first row and defining a second series of apertures having a dimension less than the dimension of said apertures of said first series, at least one of said first and second rows of apertures causing a flow stream passing therethrough to produce a pressure pulsation of a first frequency; iii) a third row of apertures located adjacent said second row and defining a third series of apertures of dimension at least equal to or greater than the dimension of said apertures of said second series; and iv) at least a fourth row of apertures located adjacent said third row and defining a fourth series of apertures of dimension at least equal to or greater than the dimension of said apertures of said third row, at least one of said third and fourth rows causing the flow stream passing therethrough to produce a pressure pulsation of a second frequency that at least substantially reduces the pressure pulsation produced by the first frequency.