Vertical boiler with injector test rig

A finely made vertical coal-fired boiler and injector test rig, a beautifully made thing by a supremely capable builder responsible for, amongst other things, the Standard Class 5, Hawthorne Leslie, Southern Pacific 2-8-0 and Southern King Arthur which we sold last year.

Based on a design described by W.A.Carter ("Testing Injectors" - Model Engineer magazine, August 1975) for a setup whereby an injector under test could be run for extended periods without either dropping the pressure of, or overfilling, the boiler supplying it with steam.

Carter acknowledged that the original idea came from a 1903 book "The Practice and Theory of the Injector" by S.L.Kneass, his contribution being to make it suitable for testing miniature injectors.

The injector on test delivers into a collection tank via a valve loaded to boiler pressure - this is achieved by means of a floating piston with connection to the boiler one side, the injector delivery on the other. A gauge shows delivery pressure of the injector on test.

We have no documentation for the boiler - we suspect it was never used outside the builder's own workshop - however a twice working pressure hydraulic test showed no evidence of leaks or distortion.