IMPROVEMENTS IN COMBINED SAFETY-VALVE AND GAUGE OR DRAW-OFF COCKS."
Year: 1881

page_text: LETTERS PATENT to Edward Field and Francis Michael Cotton, both of the
· Firm of Field, Field, and Cotton, Consulting Engineers, of Chandos Chambers,
Adelphi, in the City of Westminster, for an Invention of "IMPROVEMENTS
IN COMBINED SAFETY-VALVE AND GAUGE OR DRAW-OFF COCKS."
PROVISIONAL SPECIFICATION left by the said Edward Field & Francis
Michael Cotton at the Office of the Commissioners of Patents on the
27th January 1881.
EDWARD FIELD and FRANCIS MICHAEL COTTON, both of the Firm of Field, Field,
and Cotton, Consulting Engineers, of Chandos Chambers, Adelphi, in the City of
Westminster. "IMPROVEMENTS IN COMBINED SAFETY-VALVE AND GAUGE OR
DRAW-OFF COCKS."
Our Invention has reference to combined safety valve and gauge or draw off
cocks, wherein the plug or valve opens in opposition to a spring or load tending to
keep the plug or valve to its seat, so that fluid may be drawn off from the boiler
or vessel to which the apparatus is applied by moving the plug or valve from its
seat in opposition to the load, or if the pressure in the said boiler or vessel should
rise above that due to the load on the plug or valve it will be raised from its seat
by the pressure acting against it, and so relieve the pressure in the boiler or
vessel.
We make the plug or valve and its stem able to rotate, and we provide an incline
and a projection, one of these being carried by and moving with the plug or valve
stem, and the other being stationary, so that on turning the said stem the incline
will cause the stem to move endwise and draw the plug or valve from its seat in
opposition to the load. We arrange the apparatus so that the plug or valve can
also be partly rotated in contact with its seat, which tends to keep the plug or
valve tight, and also to prevent sticking.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Field & Francis Michael Cotton in the Great Seal Patent
Office on the 26th July 1881.
EDWARD FIELD and FRANCIS MICHAEL COTTON, both of the Firm of Field, Field,
and Cotton, Consulting Engineers, of Chandos Chambers, Adelphi, in the City of
Westminster. "IMPROVEMENTS IN COMBINED SAFETY-VALVE AND GAUGE OR
DRAW-OFF Cocks."
Our Invention has reference to combined safety valve and gauge or draw off
cocks, wherein the plug or valve opens in opposition to a spring or load tending to
keep the plug or valve to its seat, so that fluid may be drawn off from the boiler
or vessel to which the apparatus is applied by moving the plug or valve from its
seat in opposition to the load, or if the pressure in the said boiler or vessel should
rise above that due to the load on the plug or valve it will be raised from its seat
by the pressure acting against it, and so relieve the pressure in the boiler or
vessel.
We make the plug or valve and its stem able to rotate, and we provide an incline
and a projection, one of these being carried by and moving with the plug or valve
stem, and the other being stationary, so that on turning the said stem the incline
will cause the stem to move end wise and draw the plug or valve from its seat in
opposition to the load. We arrange the apparatus so that the plug or valve can
also be partly rotated in contact with its seat, which tends to keep the plug or
valve tight, and also to prevent sticking.
Referring to the accompanying Sheet of Drawings, Fig. 1 is an end elevation,
Fig. 2 is a plan, and Fig. 3 is a vertical longitudinal section of a combined safety
valve and gauge or draw off cock according to our Invention. a is the valve held
or pressed on to the seat b by the spring c which surrounds the stem d; f is a tube
or chamber screwed into the body of the cock g, and provided with an incline h
which engages with an incline i on the handle e when the latter is sufficiently
rotated. As shewn in Fig. 1 the two inclines are apart when the valve is on its
seat and the handle is in its normal position (that is, at right angles to the axis of
the cock), and consequently the valve or plug may be partly rotated in contact
with its seat to keep the said valve or plug tight, and to prevent sticking, and not
only so, but whenever the handle is turned for the purpose of opening the valve.
the first effect will be to cause a partial rotation of the valve in contact with its
seat, and the like will take place in returning the handle to its normal position to
close the valve. and Z.are two washers, the latter bearing against and compressing
the packing m. In use, the valve is exposed to fluid pressure on its lower side,
and to the pressure of the spring on its upper side. The spring pressure can at any
time be overcome by turning the handle e so as to cause the incline i to mount up
the incline h, carrying with it the valve stem and valve. The spring is so con-
structed or adjusted as to exercise a pressure on each unit area of the valve
somewhat greater than the working pressure of the boiler or vessel to which the
cock is connected, and consequently if that pressure is exceeded to any appreciable
amount the valve will be raised, and the fluid will escape.
Fig. 4 is an elevation partly in section shewing the fitting that carries the lower
end of a glass water gauge tube provided with a combined safety valve or draw-off
cock according to this Invention. n is the gauge glass fitting in the socket o, and
situated over the draw off cock g, which is similar, except in the form of its outlet,
to the cock shewn in Figs. 1, 2, and 3.
Spindles of cocks according to our Invention may be packed by glands and
stuffing boxes in the usual way, the incline h being formed upon the upper part of
the gland

page_text: Having described the nature of the said Invention, and the manner in which it
is to be or may be performed or carried into practical effect, we would have it
understood that what we consider to be novel and original, and therefore claim'as
secured to us by the Letters Patent hereinbefore in part recited is,
Constructing and arranging combined safety valve and gauge or draw off cocks
so that their plugs or valves can be partly rotated without leaving their seats,
and also can be moved from their seats by rotative movement, substantially as
described and shewn in the accompanying Drawings.
In witness whereof, I, the said Francis Michael Cotton, have hereunto set
my hand and seal, this Twenty sixth day of July, in the year of our
Lord One thousand eight bundred and eighty one.
("S"T)
'NOTIO0 'TI SIONVALL