'The Duke', is fitted with two injectors which supply water from the tender to the boiler, using a vacuum principle. One uses live steam (direct from the boiler) and the other uses exhaust steam (which has passed through the cylinders). The latter is a Davies and Metcalfe, 11mm cone, large-bodied Class K exhaust steam injector - a brand new injector manufactured by us from scratch - The first of its kind to be made since 1961. The project was a protracted saga.
The original exhaust injector fitted to 'The Duke' was, without doubt, melted down, like most injectors and non-ferrous fittings from engines scrapped at the end of steam on BR. In the early '70's, exhaust steam injectors were a rare commodity and no large Class K's were found at all, in this country or abroad. Davies and Metcalfe had a fire in their pattern store in 1962, which destroyed most of the patterns for the injectors, including those for the complicated one piece body casting of the large Class K. It was thought that many of the drawings for them had also disappeared, again including those for the large Class K body, which were absolutely essential. For these reasons, attempts to manufacture these injectors in latter days had been aborted.
In restoration, 'The Duke' was fitted with a 10mm cone, small-bodied, exhaust steam injector, which we had obtained from Italy. This proved to be inadequate for the phenomenal steaming capacity of the re-draughted boiler and we substituted a large-bodied Class K kindly loaned to us on a temporary basis by The National Railway Museum (from 70013 "Oliver Cromwell"). We began re-investigating the possibility of making a new large Class K, but with no success, until one of our most loyal supporters telephoned with a significant offer of funding and thus removed one major problem.
We asked for help from Jon Leigh, Technical Manager at Davies and Metcalfe and he began a lengthy search for anything which would assist us - things which might not have been viewed for many years. A small number of patterns and about a third of the component drawings were found. Most importantly, against expectations, a drawing of the body was discovered. However, when the latter was checked by Hugh Phillips, a specialist in this field, it was found to be unfinished. Hugh stripped our loaned injector, measured some internal dimensions and components, then completed the drawing. In the process, another discovery was made - there was a significant mistake in the body drawing. This was corrected. New component drawings were then made.
