Improvements in Pressure Gauges.
Year: 1890

page_text: Date of Application, 14th Mar., 1890
Complete Specification Left, 14th Jan., 1891-Accepted, 7th Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in Pressure Gauges.
ALEXANDER THOMAS CLARKSON, 28, Bartlett's Buildings, Holborn Circus, E.C.,
Scientific Instrument Maker, and JAMES BLEWITT SPURGE, 4, Reede Villas,
North Street, Romford, Essex, Engineer, do hereby declare the nature of this
invention to be as follows:-
:-
This invention applies to gauges employed for indicating the pressures of com-
pressed gases.
The object of this invention is to provide means to minimize the effect produced,
when the indicating portion of a gauge under pressure becomes fractured, for the
purpose of securing that surrounding bodies shall not be damaged in consequence.
The indicating part of a gauge must of necessity be of an elastic nature, and of a
particular shape, in order that a sensible distortion shall take place when a given
pressure is exerted upon it. The first of these conditions prevents any increase
being made in the thickness of the material for the purpose of strengthening it,
whilst the second involves the risk of unseen flaws being developed in the process
of shaping. Our improvement consists in filling the indicating part with an inelastic
fluid preferably pure water.
Outside the gange and communicating with the indicating part, is constructed a
small cavity or chamber of simple form, which can be made to withstand pressure
with greater certainty.
In the channel of communication a valve is fitted which is arranged to auto-
matically close it, when the difference of pressure upon each side exceeds the
normal limit. This cavity or chamber is divided into two parts by means of a
flexible partition, preferably of india-rubber forming a diaphragm.
The part in the cavity nearest to the gauge with its channel and valve is com-
pletely filled with the fluid, the function of the diaphragm being simply to retain it
in position.
This arrangement prevents access of the gases to the interior of the gauge, the
pressure being communicated by means of the fluid contained therein. At the same
time it reduces the volume required to actuate it, as the diaphragm can be fitted
close to the outer part of the cavity, and consequently the danger of admixture on
account of alternately employing the same gauge for oxygen and inflamable gases
is avoided.
The action would be as follows in the event of the indicating part fracturing, the
pressure would be suddenly released when the valve would be situated between an
enormously increased difference of pressure, which would quickly bring it into
action, close the channel and arrest any further flow.
Dated this 14th day of March 1890.
ALEXANDER THOMAS CLARKSON.
JAMES B. SPURGE.
COMPLETE SPECIFICATION.
Improvements in Pressure Gauges.
ALEXANDER THOMAS CLARKSON, of 28, Bartlett's Buildings, Holborn
Circus, E.C., Scientific Instrument Maker, and JAMES BLEWITT SPURGE, of
4, Reede Villas, North Street, Romford, Essex, Engineer, 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 :-
This invention applies chiefly to gauges of the bourdon type which are employed
Priced 1

page_text: for indicating the pressures of compressed gases, it can also be applied to other
types of gauges.
The improvement consists in filling the indicating part viz. the bourdon tube
when that type is considered, with a fluid that is but slightly compressable such as
water, soft soap, treacle, gelatin or other liquid for the purpose of preventing the
access of the gases.
In order to retain the liquid a strong chamber A provided with a moveable
partition P (such as a diaphragm or piston & cylinder arrangement) is secured to
the inlet I. In the space enclosed by the inner side of the partition F a valve V is
located, which is arranged to close the inlet at point T when a great difference of
pressure is created upon it; this space is also filled with the liquid the valve
being immersed therein. Upon the chamber a suitable union U is formed for
putting the space enclosed by the outer side of the partition into communication
with the vessel containing the compressed gas.
The action is as follows:
The gas being admitted presses upon the partition P which in its turn forces
more of the liquid into the elastic chamber (forming the indicating part of the
gauge) and distends it.
This liquid for practical purposes being considered as incompressable, only slight
movement takes place, and that with little friction, consequently no great difference
of pressure can be created that will affect the valve. On the other hand, in the
event of fracture occuring to the indicating part, the liquid would be released, a
great difference of pressure would be created, which would close the valve, and
arrest any further How.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is:
I. The filling of the indicating part of a gauge with a fluid that is but slightly
compressable, substantially as herein set forth.
11. The location of the valve V for the purpose of arresting the flow in the
event of fracture of the indicating part, substantially as herein set forth.
Dated this 14th day of January 1891
ALEXANDER T. CLARKSON
JAMES B. SPURGE.