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  Colliery Guardian, 6th February 1858
The Coal Trade—Prices of Coal—Horton’s Patent Equilibrium Valve

THE reduction in wages has had no effect upon the price of coal, which may be quoted at the Coalport Severn Wharf at former prices. The fact is, coal companies here could sell, at present rates, twice as much as they now do if they had it to dispose of; but with the prospect of an exhausted field before them, it is scarcely likely that coal owners will strip themselves of the means of working up other minerals, yet abundant, for mere temporary convenience.

I had an opportunity, the other day, at Coalbrookdale, of witnessing, in operation, one of Horton’s patent equilibrium valves- A new invention for the purpose of preventing explosions of steam boilers. It appeared to act freely and satisfactorily, giving out in puffs the surplus steam whenever the pressure became greater than that deemed desirable.

Mr. Horton, of Brierly-hill, has, for some time, devoted his attention to the construction of a valve which should be capable of retaining the steam to any desired amount of pressure, and beyond that amount of pressure, presenting an outlet of sufficient area to carry off the surplus. And which, should also be so acted upon when the water in the boiler falls below its proper level, as to allow the steam to escape. This he appears to have accomplished by means of a large valve having two seats, the upper part being fitted as an ordinary engine-piston which, so long as the steam acts on each side of it, remains closed; but the instant the steam is shut off from the upper side, opens and allows any excessive pressure to escape.

To effect this, there is affixed to the large cylinder of the piston a pipe with a valve at the top, opening upwards, and on the same stalk, at the bottom, another opening downwards.

The upper valve is loaded to the pressure required, the space between the lower one and its seat being 1/50th of an inch. When the latter valve is lifted by an increase of force that 50th of an inch, the opening is immediately closed, shutting off all steam from the top of the large piston valve in another cylinder which at once lets off the surplus and re-acts immediately to produce an equilibrium.

This action may be witnessed a hundred times a minute, so susceptible is the machine to pressure. Within the boiler is a lever of 8 inches long, with a spherical hollow float weighing 20th suspended.

The distance from the fulcrum to the centre of the valve is 3 inches, so that as the water falls, the float following it raises the small valve even if loaded to 100 lb per square inch without the assistance of steam, and only requires to move 16/50ths of an inch to open the large valve 3 inches. The invention certainly seemed to me exceedingly ingenious, and efficient, and capable of preventing the possibility of explosion from undue pressure.


Submitted by Steve Dewhirst

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