Patent ID: 8176941

Claim:
An apparatus for reducing pressure and velocity of a supersonic vent gas stream from a pressure vessel, the apparatus comprising: a) a duct extending along an axis and having an upstream portion and a downstream portion, wherein the upstream portion has an inlet for receiving the vent gas stream and diverges toward the downstream portion along at least a part of its length; wherein the upstream portion and the downstream portion of the duct have radial flanges along which they are secured together; b) a perforated plate provided inside said duct and axially positioned between the upstream and downstream portions of the duct, wherein the perforated plate has an upstream surface, an opposed downstream surface, a central portion and a peripheral portion, wherein the central portion of the perforated plate is provided with a plurality of holes extending through the perforated plate from the upstream surface to the downstream surface so as to permit the vent gas stream to flow through the perforated plate from the upstream portion of the duct to the downstream portion of the duct, and wherein the peripheral portion of the perforated plate is resiliently secured between the radial flanges of the upstream and downstream portions of the duct; c) a first body of resilient packing material provided between the radial flange of the upstream portion of the duct and the upstream surface of the peripheral portion of the perforated plate; and d) a second body of resilient packing material provided between the downstream surface of the peripheral portion of the perforated plate and an upstream surface of the support ring.