ON THE ALLEN GOVERNOR AND THROTTLE VALVE FOR STEAM ENGINES.*

A Steam Engine Governor is required to maintain a uniform speed in the working of an engine, whilst variations occur in the amount of work done; and the ordinary Watt governor, although capable of effecting this object with a close appoximation to accuracy when the variation of the power is confined with in very narrow limits, fails entirely in maintaining the speed of the engine when extensive and sudden changes occur in the resistance o be overcome.

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This defect becomes of serious consequence in some cases, such as in the engines driving rolling mills in iron works, where the whole power of the engine has to be exerted suddenly whilst the iron is passing through the rolls, and the work then as suddenly ceases, leaving only the resistance of the friction of the machinery to be overcome. In the case of a mill for rolling solid steel tyres at Mr. Kitson's works, Monkbridge, the separate engine that drives two sets of tyre rolls has to exert suddenly about 550 horse power, and then the engine is as suddenly relieved of the whole work excepting the friction of the machinery. With the Watt governor originally used for this engine and fitted with a doublebeat equilibrium valve, the speed was maintained uniformly when running light; but when rolling a tyre it was found difficult to keep up the speed, as the momentum of the flywheel became

*

Partly abridged from a paper by Mr. F. W. KITSON, in the Proceedings of the the Institution of Mechanical Engineers, May, 1873.

Meeting of the Bath and West of England Society, in June,

1873; and a working model was also shewn at the Polytechnic

Exhibition, in August of the same year.

ON THE ALLEN GOVERNOR AND THROTTLE VALVE FOR STEAM ENGINES.*

A Steam Engine Governor is required to maintain a uniform speed in the working of an engine, whilst variations occur in the amount of work done; and the ordinary Watt governor, although capable of effecting this object with a close appoximation to accuracy when the variation of the power is confined with in very narrow limits, fails entirely in maintaining the speed of the engine when extensive and sudden changes occur in the resistance o be overcome.

This defect becomes of serious consequence in some cases, such as in the engines driving rolling mills in iron works, where the whole power of the engine has to be exerted suddenly whilst the iron is passing through the rolls, and the work then as suddenly ceases, leaving only the resistance of the friction of the machinery to be overcome. In the case of a mill for rolling solid steel tyres at Mr. Kitson's works, Monkbridge, the separate engine that drives two sets of tyre rolls has to exert suddenly about 550 horse power, and then the engine is as suddenly relieved of the whole work excepting the friction of the machinery. With the Watt governor originally used for this engine and fitted with a doublebeat equilibrium valve, the speed was maintained uniformly when running light; but when rolling a tyre it was found difficult to keep up the speed, as the momentum of the flywheel became * Partly abridged from a paper by Mr. F. W. KITSON, in the Proceedings of the the Institution of Mechanical Engineers, May, 1873.

used up before the governor acted sufficiently to put on the pressure of steam necessary for carrying on the work, and the engine was often brought to a stand. To prevent loss from this cause, the engineman had constantly to stand by and handle the throttle-valve, so as to put the steam full on whenever he thought it would be required for carrying the work through; but in doing this a greater quantity of steam than necessary was very frequently put on, thereby causing destructive straining of the engine and machinery.

For regulating this engine Mr. Kitson has made trial of the Allen Governor, and it has proved thoroughly successful in removing the

above difficulty, and has been found completely satisfactory in work. During the time, nearly a year, that this governor has been in work upon the engine, the engineman has had nothing to do with the throttle-valve, and has only had to start and stop the

engine, opening the stop-valve to its full extent at starting and leaving it so, as with this governor the engine maintains the required uniform speed so long as there is sufficient steam made in the boilers to do the work. This engine when rolling a steel tyre in the finishing mill has indicated 550 horse power one minute, and only 130 horse power in the next minute, without any change being perceptible except in the rumble of the gearing

the control of the engine being effected by the governor alone, and the stop-valve remaining constantly wide open.

This Governor is the invention of Mr. Huntoon, of Boston, United States, but it is better known as the Allen Governor-the name of the American proprietor being Allen. It has been carried out by Messrs. Whitley, of Leeds.

Different forms of the