OF
A GOVERNOR, OR REGULATOR,
For Wind-Mills, Water Mills, Steam Engines, &c.
This Instrument was first intended to regulate the grinding of a wind-mill; and was used for that purpose in Kent, some time before my departure for France, in 1792. It is founded on the doctrine of opposite qualities—and is a practical combat between equal and unequal motions. In wind-mills, the mechanism is exposed to all the variations of a capricious element: and the common way of preventing these convulsive motions from injuring the flour, was for a man to attend a lever connected with the bridge tree, (which carries the upper stone) and by it to bring the stones nearer together when the wind was strong—and nearer still, when it was violent: and, contrariwise, to lift again the upper stone when the wind assumed a milder movement. A process this, which nearly equalizes the degree of grinding, but not so nearly the quality of the meal—for this is found to be more heated by great, than by moderate velocities. At all events I thought a Machine like the present, would regulate this process, as well as a man; and it was found to do so—except, perhaps, in very extreme cases.
This Governor, is represented in [fig. 1] of [Plate 27]—the ground work of which is the same as that of the [third figure] in [Plate 3]: for in reality the present Machine claims the precedence of the Dynamometer; and may therefore, well borrow a figure from it’s description. A is the power-axis, receiving motion from any proper shaft of the mill. It is turned backward by that shaft, and therefore tends to raise the ball B—an operation equivalent to bringing the mill-stones nearer together. At the same time, the axis of resistance C, carries round a pallet-wheel D E, and by the pallet D, sets the pendulum F G a vibrating, which therefore, by every stroke, lets down the ball B, and thus raises the upper mill-stone. A proper position of the latter depends on the similarity of the motion of the power-axis A, which winds up the ball B, and that of the axis C, which lets it down. While these are equal, the weight B remains stationary, and the work goes on well. But if a gust of wind increases the speed of the mover A, (the pendulum F G confining the axis C to it’s usual speed) the ball B is immediately raised and the stones brought closer—which is what the grinding process requires: And should that gust increase in violence and become a hurricane, the intermediate cylinder M, while producing that effect, carries also with it the cord H I, and thereby raises the bob G of the pendulum, and thus fits this movement to the increased speed of the mill: raising, sometimes, the bob to the very centre F of it’s vibration, where it’s oscillations become rapid enough to unwind all the excess of motion which the hurricane had occasioned; until, the wind subsiding, the pendulum acquires a medium length, and things go on moderately as before.
It may be observed, that the present form of this Machine is not quite so simple as it might have been made; nor is it so simple as it first was. The required motions being much shorter than those of a Dynamometer, the cylinder M, among other things, might be dispensed with; and one of the intermediate wheels be likewise suppressed. And if we advert to the retarding principle which resides in the pendulum, the well known conical pendulum might be substituted for the present one; since from it would arise a regular or equable resistance, opposed to an equable effort. Some however, might then consider the conical pendulum as an ordinary centrifugal governor; and, as a mere retarding principle, it may be thought too complex for the occasion: but I think on the contrary, that it’s use in this connection, would make this Machine one of the best of regulators, as well for steam engines as for water and wind-mills of every description: especially if fitted up with my Patent Geering.