IMPROVE- MENTS IN STOPCOCKS OR SAFETY TAPS
Year: 1881

page_text: LETTERS PATENT to Charles Stuart, of Bletchley Iron Works, Fenny Stratford,
in the County of Bucks, Mechanical Engineer, for an Invention of "IMPROVE-
MENTS IN STOPCOCKS OR SAFETY TAPS."
PROVISIONAL SPECIFICATION left by the said Charles Stuart at the Office
of the Commissioners of Patents on the 29th November 1881.
CHARLES STUART, of Bletchley Iron Works, Fenny Stratford, in the County
of Bucks, Mechanical Engineer. "IMPROVEMENTS IN STOP COCKS OR SAFETY
TAPS."
This Invention refers to the manner of working the valves and valve spindles
of stop cocks or safety taps for the purpose of ensuring rapid and automatic closing
and opening.
The valve is held in its seat by a spring of a power equivalent to the required
maximum pressure of the steam in the boiler or other vessel to which the tap is
attached in such a manner that any excess above that pressure immediately lifts
the valve and allows the steam to escape. As soon as the steam is reduced to its
normal pressure the valve drops automatically, and closing the aperture prevents
any further escape.
The valve can also be at once raised and instantaneously closed again by turning
the handle if needed to allow the escape of water or otherwise.
To produce this result a helical feather is cut on the valve spindle, and a groove
of equal width is cut in the female screw formed in the interior of the valve-box,
so that the moment the feather is brought opposite the groove the spindle drops,
and the valve closes again instantaneously.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Stuart in the Great Seal Patent Office on the 26th May
1882.
CHARLES STUART, of Bletchley Iron Works, Fenny Stratford, in the County
of Bucks, Mechanical Engineer. "IMPROVEMENTS IN STOP COCKS AND SAFETY
TAPS."
My Invention refers to the manner of working the valves and valve spindles
of stop cocks and safety taps for the purpose of ensuring rapid and automatic
opening and closing.
The valve is held in its seat by a spring of a power equivalent to the required
maximum pressure of steam in the boiler or other vessel to which the tap is
attached in such a manner that any excess above that pressure immediately lifts
the valve and allows the steam to escape. As soon as the steam recovers its
normal pressure the valve drops automatically, and closing the aperture prevents
any further escape.
The valve can also be at once raised if necessary to allow the escape of water or
otherwise by a turn of the handle, and when the turn is finished will close again
instantaneously. A helical feather is cut on the valve spindle, and a groove of
equal width is cut on the female thread in the interior of the valve box, so that
the moment the feather is brought opposite to the groove the spindle drops, and
the valve closes again.
In further explanation of my said Invention I annex a Drawing.
In this J is the spindle or valve box having the female screw and the slot cut in
it, and E is the spindle having a screw cut feather to work in the slot. By
moving the handle A the spindle E is raised, and when one revolution is completed
the aforesaid feather meets tho slot, and the pressure of the spring F forces the
spindle back to its normal position, the rising and falling being thus repeated at
cach revolution.
The same principle is also applicable to pump plungers, lubricators, injectors,
and other apparatus for the outflow and injection of fluids, steam, or gases.
Having thus explained the nature of my Invention, I declare my claim to bc,-
The particular method of actuating valves and valve spindles, plungers, and
other apparatus for the outflow or injection of steam, fluids, or gases, substantially
as set forth herein, but without confining myself to the exact configuration shown
in the Drawing.
In witness whereof, I, the said Charles Stuart, have hereunto set my hand
and seal, this Twenty-fifth day of May, One thousand eight hundred and