Improvements in Piston Rod Packing.
Year: 1889

page_text: Date of Application, 11th Feb., 1889
Complete Specification Left, 6th Nov, 1889-Accepted, 7th Dec., 1889
PROVISIONAL SPECIFICATION.
Improvements in Piston Rod Packing.
I, ISAAC BLUE HARRIS of Castle Mills Fountainbridge, Edinburgh, India Rubber
Manufacturer, do hereby declare the nature of this invention to be as follows:-
These improvements relate to the manufacture of piston rod packing more
particularly for high pressure steam and consist in the employment as heroinafter
described of brass or metallic wire cloth coated with india rubber.
A web of wire cloth is coated with india rubber in the same way as a web of
textile material. By this means the openings between the wires of which the web
is woven are completely filled up with india rubber and furthermore any number
of layers of such coated wire cloth can be cemented together by the said contings.
Such coated wire cloth is cut into suitable strips. In order to make those available
for piston packing wrap the wire cloth strips round a core of india rubber or
other elastic material to get a cord of any required diameter. I lay the wire cloth
cord in a spiral form about a round mandril and keep it in that form while the
rubber thereof is being vulcanised. After it is vulcanised the cord forming the
packing remains in a circular and spiral form and all that is required in applying
it to a given rod and stuffing box is to cut off two or more rings of suitable
length or inside circumference so that they will barely encircle the piston rod.
The packing thus consists of two or more cut rings placed so that the cut of one
ring is against the whole part of the one next it that is the rings are so placed
as to "brake joint."
The metallic wire cloth is unaffected by the heat of steam and the whole forms
a durable packing not liable to char with heat like packing made of textile
materials.
Dated this 11th day of February 1889.
CARPMAEL & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in Piston Rod Packing.
I, ISAAC BLUE HARRIS of Castle Mills, Fountainbridge, Edinburgh, India Rubber
Manufacturer, 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 :-
These improvements relate to the manufacture of piston rod packing more
particularly for high pressure steam and consist in the employment as hereinafter
described of brass or metallic wire cloth coated with india rubber.
A web of wire cloth is coated with india rubber in the same way as a web of textile
material. By this means the openings between the wires of which the web is woven
are completely filled up with india rubber and furthermore any number of layers of
such coated wire cloth can be cemented together by the said coatings. Such coated
wire cloth is cut into suitable strips. In order to make these available for piston
packing I wrap the wire cloth strips round a core of india rubber or other elastic
material to get a cord of any required diameter. I lay the wire cloth cord in a spiral
form about a round mandril and keep it in that form while the rubber thereof is being
vulcanised. After it is vulcanised the cord forming the packing remains in a circular
and spiral form and all that is required in applying it to a given rod and stuffing box
is to cut off two or more rings of suitable length or inside circumference so that they

page_text: will barely encircle the piston rod. The packing thus consists of two or more cut
rings placed so that the cut of one ring is against the whole part of the one next it-
that is the rings are so placed as to "break joint."
The metallic wire cloth is unaffected by the heat of steam and the whole formng
a durable packing not liable to char with heat liko packing madu of textile
materials.
The following is the manner in which I prefer to proceed :-
I take wiro cloth, preferably copper, closely woven and sufficiently fine to he
readily formed into a roll. I coat this wire cloth thinly on both sides with india
rubber composition suitable for vulcanising and then cut the sheet of wire cloth
obliquely from side to sido into bands. The cloth is cut so that the wires cross the
band at an angle of about 45 degrees. These bands are then laid end to end to any
desired length with an overlap of about one inch in each case.
The core of india rubber of the required length and circular or rectangular in
section is laid upon the prepared bands of wire cloth and these are wound closely
around it until any required diameter or thickness of roll or cord is obtained; the
width to which the bands are cut being such as to give the thickness of cord
required.
Then I wind the roll or conl in a close spiral upon a mandril of about the same
diameter as the piston rod with which the packing is to be used, and whilst on the
mandril vulcanise the roll or cord in the usual way. The mandril is then withdrawn
and the packing is ready for use.
Although it is preferred to have an india rubber core, this may in some cases he
omitted.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
A packing substantially as described consisting of wire gauze, coated with india
rubber composition, formed into a cord or rope with or without a core and vulcanised
in a circular form as herein set forth.
Dated this 6th day of November 1889.
CARPMAEL & Co.,
Agents for the Applicant.