Abstract: An object is to provide a decompression device including a plurality of stages of orifice plates disposed in a flow passage, which generates less noise in response to sonic feedback phenomenon and gas-column resonance. A decompression device 10A includes: an upstream orifice plate 14 disposed in a duct 12 forming a flow passage for a fluid F; and a downstream orifice plate 16 disposed in the flow passage and downstream of the upstream orifice plate 14. A jet-flow interference part 22A is disposed only partially on an outlet rim portion of an orifice 18 on the upstream orifice plate 14 and configured to interfere with a jet flow discharged from the orifice 18. Positions of Karman vortices e are differentiated in a duct axial direction between regions with and without the jet-flow interference part 22A to reduce generation of noise.

Abstract: An object is to provide a decompression device including a plurality of stages of orifice plates disposed in a flow passage, which generates less noise in response to sonic feedback phenomenon and gas-column resonance. A decompression device 10A includes: an upstream orifice plate 14 disposed in a duct 12 forming a flow passage for a fluid F; and a downstream orifice plate 16 disposed in the flow passage and downstream of the upstream orifice plate 14. A jet-flow interference part 22A is disposed only partially on an outlet rim portion of an orifice 18 on the upstream orifice plate 14 and configured to interfere with a jet flow discharged from the orifice 18. Positions of Karman vortices e are differentiated in a duct axial direction between regions with and without the jet-flow interference part 22A to reduce generation of noise.

Abstract: An object is to provide a heat exchanger including a resonance-prevention baffle plate disposed between a plurality of heat transfer tubes, the resonance-prevention baffle plate being obtainable and mountable readily and at lower cost. A heat exchanger 10 disposed in a flow passage of combustion gas of a boiler or the like includes: a plurality of heat transfer tubes 14 disposed in parallel and spaced from one another, an axial direction of each heat transfer tube intersecting with the combustion gas g, inside a duct wall 12 forming the flow passage of the combustion gas g; and a resonance-prevention baffle 16 having a plate shape and disposed along the combustion gas g and between the heat transfer tubes 14, the resonance-prevention baffle including a metal foil sheet 18.

Abstract: A heat transfer pipe support structure has a heat transfer pipe support plate with through-holes formed therein, heat transfer pipes inserted through the through-holes, and a vibration-damping support plate joined to the heat transfer pipe support plate. An edge of the vibration-damping support plate is joined to the heat transfer pipe support plate so that the heat transfer pipes are held between the edges of the through-holes and the vibration-damping support plate. As a result, the clearance between the edges of the through-holes and the heat transfer pipes is reduced, enabling vibration of the heat transfer pipes to be reduced. This results in a reduction of sliding movement of the heat transfer pipes with respect to the edges of the through-holes, and thereby, wear of the heat transfer pipes is reduced.

Abstract: A multistage pressure reduction device (10) of the present invention includes a fuel pipe (1) forming a flow path (5), an upstream orifice plate (2) disposed in the flow path (5), and a downstream orifice plate (3) disposed downstream of the upstream orifice plate (2) in the flow path (5). The upstream orifice plate (2) is formed such that a jet flow (7-i) discharged from a hole (6-i) formed at the upstream orifice plate (2) contacts a certain target. With this multistage pressure reduction device (10), the jet flow (7-i) discharged from the upstream orifice plate (2) contacts the certain target to prevent air column resonance excited between the upstream orifice plate (2) and the downstream orifice plate (3). Noise due to the air column resonance can be reduced without providing a porous metal between the upstream orifice plate (2) and the downstream orifice plate (3).