IMPROVEMENTS IN VALVES FOR REGULATING THE FLOW OF GAS IN MAINS AND OTHER PASSAGES
Year: 1884

page_text: "
I EDWIN BRYAN DONKIN of Bermondsey in the County of Surrey Mechanical
Engineer do hereby declare the nature of my Invention for "IMPROVEMENTS
IN VALVES FOR REGULATING THE FLOW OF GAS IN MAINS AND OTHER PASSAGES
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:—
This Invention has for its object improvements in valves for regulating the flow
of gas in mains and other passages.
The gas valves at present in common use for such purposes usually consist of a
sliding door which is moved along a face so as to cover or uncover a mouth by
which the gas passes.
As at present constructed these sliding doors are held up
to the face by means of a blade spring attached by its centre to the sliding door
and pressing by its ends against guide surfaces within the valve case.
The door receives its movement from a rack formed upon its back, and with
this rack a pinion engages. In some cases a screw is employed to give motion to
the sliding door and other means are also employed.
In valves having blade springs the spring frequently breaks, and when it does
so, there is not only the trouble of replacing it, but frequently the broken spring
jams the valve so that it cannot be noved and considerable inconvenience
sometimes arises.
According to my Invention I dispense altogether with the blade spring, and
I form cavities in the back of the sliding door, one on either side of it. In each
of these cavities I lodge a volute or spiral spring and over this spring I place a
cap. The cap is held by the spring in contact with the guide surface provided
within the valve case, and its reaction keeps the door to its face. These springs
rarely break and when they do the pieces are retained in the cavity by the cap
and the door does not become jamined.
In order that my said Invention may be most fully understood and readily
carried into effect I will proceed to describe the Drawings hereunto annexed.

page_text: and the door B. In the position in which the parts are shown the door closes the
mouth in the valve case and prevents the passage of gas.
B is the rack formed upon the back of the valve; it is as heretofore except that
it is without the slot which is necessary when a blade spring is employed for the
insertion of the said spring beneath the rack.
B* B* are the two chambers or cavities one on either side of the sliding door in
which the volute or spiral springs C C are contained.
Figure 4 shows to a large scale a portion of the sliding door and also of
the case.
Figure 5 is a horizontal section showing the same portion of the sliding door
together with parts A and A¹ of the valve case. Here the spring C is seen within
the chamber or cavity B and over it the cap D. This figure shows also the guide
faces at A* A* upon which the caps D D rest. The faces A* A* form abutments
for the springs Cagainst which they react whilst they press the outer edges of the
sliding door at two diametrically opposite points against the face formed around
the mouth by which when the said mouth is uncovered the gas issues.
In the Drawings volute springs are represented but in lieu of these spiral springs
may be employed. Volute springs as shown are however preferred.
The gas tight closing of the valve is not wholly dependent on the springs C. C
but the back of the sliding door and the guide faces are slightly inclined so that
when the door is in its lowest position it is as is usual pressed up to its face by
the wedge like action of these surfaces. The springs serve to hold the door to the
face during its movement and so to prevent the accumulation of tar upon the face
which would otherwise occur and interfere more or less with the action of the
valve.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is Gas valves constructed as herein described with spiral or volute springs
contained within chambers one on either side of the valve and provided with caps
abutting upon guide faces substantially as herein described.
1
JA
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17
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CARPMAEL & Co.,
Agents for the Applicant.