Improvements in India-rubber Valves.
Year: 1890

page_text: Date of Application, 19th Feb., 1890
Complete Specification Left, 13th Nov., 1890-Accepted, 13th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in India-rubber Valves.
I, ISAAC BLUE HARRIS; Superintendent of the North British Rubber Co's. (Limited)
Works, in the City of Edinburgh, do hereby declare the nature of this invention to be
as follows:-
Much inconvenience and trouble, especially at sea, are caused by ordinary india
rubber valves,particularly those used in air pumps, enlarging in diameter or area under
the influence of the oils to which they are exposed, and the object of this invention is
to prevent that enlargement and the consequent disadvantages and also to secure
greater durability and security in the use of such valves.
I form the sheet of unvulcanized rubber, from which a valve is to be made, half
the thickness of the finished valve. I then cut two discs therefrom of the diameter
intended for the valve. I also cut two or more discs of cotton or other fabric of equal
warp and weft which has been covered on both sides with a cementing layer of rubber.
These rubber covered cloth discs I cut a little less in outside diameter than that of the
rubber discs. I also cut a central hole in each of the cloth discs, so as to be a little
larger in diameter than that of the central hole wanted in the valve. These coated
cloth discs are placed concentrically between the two rubber discs, and when they are
pressed together during the process of vulcanization the cloth discs will be completely
surrounded with solid rubber, and thereby insulated from wet. The cloth discs are
placed singly hetween the rubber dises and so that the warp or weft of the one may
make an angle less than a right angle with the warp or weft of the other. (If two
cloth discs are used the angle will be 45°; if three discs, the angles will be 30° and 60°
and so on.) The above mode of construction is applicable to valves made of one
quality of rubber, but I prefer the following construction, which forms an important
feature of my invention.
I make each of the solid rubber discs of two qualities of rubber in the following
manner. The central parts of the two solid rubber discs in which the hole wanted in
the valve is to be cut are made of that combination of rubber and sulphur which forms
vulcanite when vulcanized, and the outer and larger part of each disc of ordinary
flexible india rubber, the two qualities uniting during vulcanization. The vulcanite
centres thus formed in the valves are advantageous in ordinary valves, in which they
have been long used, but according to my invention I form them tapering outwards
which renders the hard and soft rubber much less liable to separate than when the two
square edges only come together. Then the inner edges of the cloth discs are placed
between the vulcanite tapering rings, and those edges are thereby held and the
enlargement of the valve prevented more effectively than when placed between discs
of soft rubber only. The middle layers of rubber valves have occasionally been made
with cloth for the purpose of reducing the flexibility of the rubber, but they have not
been disposed or placed to prevent the extension or enlargement of the valves, and
cloth discs have not hitherto been used stayed at their inner edges with vulcanite or
hard rubber as herein described. I find it very convenient to form the vulcanite
centre of the valve in three pieces, first a ring of rectangular section having an
internal diameter equal to the hole wanted in the valve and equal in thickness thereto;
and second and third, two tapering rings fitting on to the first each nearly half the
thickness of the valve, having the inner edges of the cloth discs placed between them.
The whole of the points, namely, the three hard rings forming the centre, the rubber
coated cloth discs which prevent the enlargement of the valve, and the flexible rubber
discs on either side of the cloth discs and forming therewith the flexible part of the

page_text: valve will all unite as is well known during the process of vulcanization and form a
composite flexible valve inextensible in diameter in all directions.
Dated this 19th day of December 1890.
CARPMAEL & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in India-rubber Valves.
I, ISAAC BLUE HARRIS, Superintendent of the North British Rubber Co's. (Limited)
Works, in the City of Edinburgh, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
Much inconvenience and trouble, especially at sea, are caused by ordinary india
rubber valves, particularly those used in air pumps, enlarging in diameter or area
under the influence of the oils to which they are exposed, and the object of this
invention is to prevent that enlargement and the consequent disadvantages and also to
secure greater durability and security in the use of such valves.
I form the sheet of unvulcanized rubber, from which a valve is to be made, half
the thickness of the finished valve. I then cut two discs therefrom of the diameter
intended for the valve. I also cut two or more discs of cotton or other fabric of equal
warp and weft which has been covered on both sides with a cementing layer of rubber.
These rubber covered cloth discs I cut a little less in outside diameter than that of the
rubber discs. I also cut a central hole in each of the cloth discs, so as to be a little
larger in diameter than that of the central hole wanted in the valve. These coated
cloth discs are placed concentrically between the two rubber discs, and when they are
pressed together during the process of vulcanization the cloth discs will be completely
surrounded with solid rubber, and thereby insulated from wet. The cloth discs are
placed singly between the rubber discs and so that the warp or weft of the one may
make an angle less than a right angle with the warp or weft of the other. (If two
cloth discs are used the angle will be 45°; if three discs, the angles will be 30° and 60°
and so on.)
Figure 1 of the annexed drawings is a section of a valve disc thus constructed. a is
the soft india rubber and bis the cloth embedded and enclosed within it so that the
edges of the cloth are covered.
The above mode of construction is applicable to valves made of one quality of
rubber but I prefer the following construction which forms an important feature of
my invention.
I make each of the solid rubber discs of two qualities of rubber in the following
manner. The central parts of the two solid rubber discs in which the hole wanted in
the valve is to be cut are made of that combination of rubber and sulphur which forms
vulcanite when vulcanized, and the outer and larger part of each disc of ordinary
flexible india rubber, the two qualities uniting during vulcanization. The vulcanite
centres thus formed in the valves are advantageous in ordinary valves, in which they
have been long used, but according to my invention I form them tapering outwards
which renders the hard and soft rubber much less liable to separate than when the two
square edges only come together. Then the inner edges of the cloth discs are placed
between the vulcanite tapering rings, and those edges are thereby held and the
enlargement of the valve prevented more effectively than when placed between discs
of soft rubber only.
Figure 2 shows a section of a valve disc in which the hard rubber centre is applied
in accordance with my invention. a is the soft rubber and a' is the hard rubber
meeting the soft rubber in an oblique joint.
Figure 3 shows a section of a valve disc with cloth embedded and in which the
inner edge of the cloth is surrounded by and united with the hard rubber.
The middle layers of rubber valves have occasionally been made with cloth for the

page_text: purpose of reducing the flexibility of the rubber but they have not been disposed or
placed to prevent the extension or enlargement of the valves, and cloth discs have not
hitherto been used stayed at their inner edges with vulcanite or hard rubber as herein
described. I find it very convenient to form the vulcanite centre of the valve in three
pieces, first a ring of rectangular section having an internal diameter equal to the hole
wanted in the valve and equal in thickness thereto; and second and third, two
tapering rings fitting on to the first each nearly half the thickness of the valve, having
the inner edges of the cloth discs placed between them. The whole of the parts,
namely, the three hard rings forming the centre, the rubber coated cloth discs which
prevent the enlargement of the valve, and the flexible rubber discs on either side of the
cloth discs and forming therewith the flexible part of the valve will all unite as is well
known during the process of vulcanization and form a composite flexible valve
inextensible in diameter in all directions.
Figure 4 shows in section the parts of a valve disc which is thus built up; the
several portions are represented as separated somewhat the one from the other but it
will be understood that this for the purpose only of showing them clearly in the
drawing. In building up the dise from these parts they are laid one on the other,
brought into close contact and vulcanized into one mass. a is the soft rubber.
a a a³ are the rings of rubber which in vulcanizing become hard and b b are the
cloth discs.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. Constructing an india rubber valve disc substantially as described by enclosing
discs of india rubber covered cloth between discs of prepared india rubber in such
manner that the edges of the cloth are not exposed and then vulcanizing and uniting
the whole into one mass.
2. A valve disc with cloth embedded and completely enclosed and formed partly of
soft and partly of hard rubber, the whole vulcanized and united into one mass,
substantially as described.
3. Constructing a valve disc substantially as described partly of hard and partly of
soft rubber in such manner that the joint between the two kinds of rubber is oblique
or inclined to the face of the disc.
4. Constructing a valve disc substantially as described partly of hard and partly of
soft rubber with discs of cloth embedded and completely enclosed; the inner edges of
such discs being surrounded by and united with the hard rubber and the outer edges
with the soft rubber.
Dated this 10th day of November 1890.
CARPMAEL & Co.,
Agents for the Applicant.