Abstract: Noise attenuation during the purging of pipes by means of steam blowing is achieved by the use of a receptacle into which steam is blown upon discharge from one end of a pipe; a linkage pivotally suspends an exchangeable mouthpiece adjacent to a front end opening of the receptacle and carries a stop member; actuation of the linkage places the mouthpiece over a front end of the pipe adjacent to said opening while removing said stop and, alternatively, places the mouthpiece over a front end of the pipe adjacent to said opening while removing said stop and, alternatively, pivots the mouthpiece to clear the pipe while causing the stop member to be placed in front of that front end.

Abstract: Zinc coated tubes are cleaned by means of steam, and the zinc residue -- steam mixture is blown into a nozzle which is heated, and discharged into a noise attenuation chamber; the latter discharges into an expansion chamber, which in turn discharges into a filter. The mixture is diluted in the attenuation chamber by air sucked in from the outside along a tortuous path.