An Improved Gascheck for Pressure Gauges used in Guns and for Sealing Joints against Gaseous or Fluid Pressures.
Year: 1898

page_text: Date of Application, 7th May, 1898
Complete Specification Left, 20th Feb., 189)-Accepted, 25th Mar., 1899
PROVISIONAL SPECIFICATION.
An Improved Gascheck for Pressure Gauges used in Guns and for
Sealing Joints against Gaseous or Fluid Pressures.
HENRY CAPEL LOFFT HOLDEN, Major, Royal Artillery, Royal Arsenal, Wool-
wich, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved means of preventing the escape of gas or
fluid past a piston such as is used in a pressure gauge, usually termed a crusher
gauge, as used in a gun, or past any joint which is required to be absolutely
tight under gaseous or fluid pressures at any pressure and at any temperature.
When applied to the piston of a pressure gauge my gascheck consists of two
parts; the first being a disc of steel or other suitable material of the same
diameter as the piston itself and of such a thickness as may meet the require-
ments of the case, having on the side of it next to the piston a projection or
projections the use of which will be explained hereafter the second portion con-
sists of a wad or disc of fibrous material, such as asbestos, which may with advan-
tage for the purpose of reducing friction be mixed with a lubricant such as
tallow graphite or mica. This wad should be of suitable thickness in proportion
to its diameter and from one half to one third of the diameter would generally
be suitable though it might be more or less than this. In order to secure this
wad to the steel disc the latter has, as has already been stated a projection or
projections on the side of it next the wad; this projection or projections enter
the wad and secure the two together the wad may, if preferred, be similarly
attached to the piston or to both the piston and disc.
The gaseous or fluid pressure acts upon the disc which is a close working fit
to the cylinder and compresses the wad between itself and the piston, thus com-
pletely filling without any clearance the space between the two, thereby prevent-
ing any escape whatever past the piston even under extreme pressures at the
highest temperatures. The same or similar means can be employed to seal any
joint or opening, suitable modifications of form being made to suit the particular
purpose.
Dated thi Pil Ja Ma.. 1000
An Improved Gascheck for Pressure Gauges used in Guns and for
Sealing Joints against Gaseous or Fluid Pressures.
HENRY CAPEL LOFFT HOLDEN, Major, Royal Artillery, Royal Arsenal, Wool-
wich, 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;
-
My invention relates to an improved means of preventing the escape of gas

page_text: or fluid past a piston such as that used in a pressure gauge, commonly called a
crusher gauge, for ordnance; such a piston is required to make an absolutely
gas-tight joint under the greatest pressures and highest temperatures of the
explosive, whether this be in the gaseous or liquid state; my gascheck effects
this purpose perfectly, whilst allowing the utmost freedom of movement to the
piston, thus avoiding almost entirely the errors due to friction, which latter by
reducing the effective pressure on the copper cylinder causes the record of pres-
sure obtained by means of the compression of the cylinder to be more or less
inaccurate. When applied to the piston of a pressure gauge, usually termed a
crusher gauge employed in guns, my gascheck consists of two parts, the first is
a disc of steel or other suitable material, of the same diameter as the piston and
of such a thickness as may be necessary to meet the requirements of the case,
having on the side of it next to the piston a projection or projections the use of
which will be explained hereafter; the second portion consists of a wad or pad
of fibrous material, such as asbestos, in the form of a disc, which may with
advantage be mixed with a lubricant such as tallow, graphite or powdered mica:
the object of the lubricant being to reduce the friction between the surfaces of
the piston and the cylinder in which it works; a suitable thickness for this wad
would be from one half to one third of its diameter, but it may be greater or
less than this as circumstances may dictate. In order to secure the wad to the
steel disc, the latter has, as has already been stated, a projection or projections
on the side of it next to the wad the projection or projections being of such a
length and form as to enter the wad and attach it to the steel disc. The wad
may in like manner be attached to the piston when so required.
Referring now to the accompanying drawing in order to explain my invention
more clearly and the manner in which it is carried into effect. D is the body of
an ordinary crusher gauge containing the usual copper cylinder F, which is com-
pressed under the action of the pressure transmitted through the piston C which
is a working fit in the portion G which constitutes the remainder of the body of
the gauge over the piston C is placed the pad of fibrous and lubricating
material B into which the projection E of the steel disc A enters in such a
manner as to hold the two together.
When the gauge is placed in the gun and the charge fired the pressure acts
on the disc A forcing the material of the wad B into intimate contact with the
surface of G and absolutely preventing the passage of gases or liquids into the
interior of the gauge.
The same arrangement may be used for analogous purposes in guns, such as
for sealing the piston of a base fuze or the joint between the base fuze itself and
the body of the projectile in which it is fixed.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The combination of a steel or other disc and a fibrous wad impregnated
with lubricant so as to form together a gascheck which can be applied to the
piston of a crusher gauge or analogous contrivance.
2. The gascheck substantially as described and for the purposes set forth.
Dated this 13th day of February 1899.
H. C. L. HOLDEN,
G. F. Redfern & Co.,
Major, R.A.
4, South Street, Finsbury, London, Agents for the Applicant.