page_title: Blastpipe
section_title: Later development
hierarchical_section_title: Blastpipe / Later development
caption_attribution_description: Kylchap steam locomotive exhaust system Personal 3D diagram modeled with Google SketchUp
context_page_description: The blastpipe is part of the exhaust system of a steam locomotive that discharges exhaust steam from the cylinders into the smokebox beneath the chimney in order to increase the draught through the fire.
context_section_description: Little development of the basic principles of smokebox design took place until 1908, when the first comprehensive examination of steam-raising performance was carried out by W.F.M. Goss of Purdue University.  These principles were adopted on the Great Western Railway by Churchward.  A later development was the so-called jumper-top blastpipe which controlled the area of the blastpipe at different steaming rates to maximise efficiency.
  The aim of blastpipe modification is to obtain maximum smokebox vacuum with minimum back pressure on the pistons. The simplest modification is a double chimney with twin blastpipes, but many other arrangements have been tried.  Towards the end of the steam era the Kylchap exhaust was popular and used on the Nigel Gresley's Mallard.  Other designs include Giesl, Lemaître and Lempor blastpipes.
caption: The Kylchap exhaust system
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