IMPROVEMENTS IN PRESSURE AND VACUUM GAUGES
Year: 1877

page_text: LETTERS PATENT to William Campbell Eyton, of Weston Stevenage, Herts,
for the Invention of "IMPROVEMENTS IN PRESSURE AND VACUUM GAUGES."
Sealed the 2nd November 1877, and dated the 4th May 1877.
PROVISIONAL SPECIFICATION left by the said William Campbell Eyton at
the Office of the Commissioners of Patents on the 4th May 1877.
WILLIAM CAMPBELL EYTON, of Weston Stevenage, Herts.
PRESSURE AND VACUUM GAUGES."
"IMPROVEMENTS IN
My improvements in pressure gauges refer more particularly to that class of
gauge used in connection with steam boilers, although they are also applicable in all
cases in which it is desired to determine any fluid or gaseous pressure, or the degree
of absence of such pressure.
In ordinary gauges the pressure either acts (through the medium of a curved
tube, as in the Bourdon gauge, or of an elastic diaphragm, or of some other suitable
arrangement) through a more or less complicated and delicate system of mechanismı
upon an oscillating index needle, the whole of which is both liable to derangement,
and is considerably affected by changes in the external temperature, or else the fluid
where pressure is to be estimated acts directly on one extremity of a column of
mercury, the opposite extremity of which is either exposed to atmospheric pressure,
or is exposed to the action of a portion of air confined in the upper part of the con-
taining tube, the indications in both these cases being given by the position of the
mercury in the tube. Neither of these forms is fairly portable, and both are subject
to variations due to atmospheric temperature.
To obviate the objections alluded to I construct my improved gauge in the
following manner: The lower part of the gauge consists of a funnel-shaped
receptacle, into which the steam, gas, or other fluid, where pressure is required to be
determined, is admitted. Upon this is placed a similar but inverted vessel, the two
being attached to each other by a flange or other suitable joint. Between these
two vessels is placed an elastic diaphragm of metal or other suitable material (pre-
ferably of corrugated nickel plated steel), the under side of which is pressed by the
steam, gas, or other fluid. A strong glass tube hermetically sealed at the upper end
is firmly fixed into a suitable aperture in the upper or inverted funnel, such tube
Paine 77

page_text: being wholly or partially filled with atmospheric air at the ordinary pressure, or at
any other degree of tension that may be convenient, the air being confined by
mercury or other convenient medium with which the upper funnel is wholly or
partially filled, and through which the pressure acting on the elastic diaphragm is
transmitted to the confined air, causing the latter to occupy a space in the tube
proportionate to the pressure exerted on the diaphragm, the degree of such
pressure being indicated by the position of the mercury in the tube to which a
suitable seal is attached.
In order to compensate for the effects of variation in atmospheric temperature I
propose (in the case of steam or of any other fluid or gas where pressure may be
due to the amount of heat to which it is subjected) to enclose the upper part of the
gauge, viz., that containing the air and mercury, in a second vessel or jacket suitably
constructed of glass and metal, through which the steam or other fluid shall circulate,
thus keeping the contained air and mercury at the same temperature as the fluid
where pressure is to be determined. It is at once obvious that as steam at any
given pressure is always at the same temperature all difficulty arising from external
variations of temperature is at once overcome.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Campbell Eyton in the Great Seal Patent Office on the
3rd November 1877.
WILLIAM CAMPBELL EYTON, of Weston Stevenage, Herts.
PRESSURE AND VACUUM GAUGES."
"IMPROVEMENTS IN
My Invention in pressure gauges refer more particularly to that class of gauge
used in connection with steam boilers, although they are also applicable in all cases
in which it is desired to determine any fluid or gaseous pressure, or the degree of
absence of such pressure.
In ordinary gauges the pressure either acts (through the medium of a curved
tube, as in the Bourdon gauge, or of an elastic diaphragm, or some other suitable
arrangement) through a more or less complicated and delicate system of mechanism
upon an oscillating index needle, the whole of which is both liable to derangement,
and is considerably affected by changes in external temperature, or else the fluid
where pressure is to be estimated acts directly on one extremity of a column of
mercury, the opposite extremity of which is either exposed to atmospheric pressure,
or is exposed to the action of a portion of air confined in the upper part of the
containing tube, the indications in both these cases being given by the position of
the mercury in the tube. Neither of these forms is fairly portable, and both are
subject to variations due to atmospheric pressure.
To obviate the objections alluded to I construct my improved gauge in the
following manner :-The lower part of the gauge consists of a funnel-shaped
receptacle, into which the steam, gas, or other fluid where pressure is required to
be determined is admitted. Upon this is placed a similar but inverted vessel, the
two being attached to each other by a flange or other suitable joint. Between
these two vessels is placed an elastic diaphragm of metal or other suitable material
(preferably of corrugated nickel plated steel), the under side of which is pressed by
the steam, gas, or other fluid. A strong glass tube hermetically sealed at the upper
end is firmly fixed into a suitable aperture in the upper or inverted funnel, such
tube being wholly or partially filled with atmospheric air at the ordinary pressure
or at any other degree of tension that may be convenient, the air being confined by
mercury or other convenient medium with which the upper funnel is wholly or
partially filled, and through which the pressure acting on the elastic diaphragm is
transmitted to the confined air, causing the latter to occupy a space in the tube
proportionate to the pressure exerted on the diaphragm, the degree of such pressure
1

page_text: being indicated by the position of the mercury in the tube, to which a suitable seal
is attached.
In order to compensate for the effects of variation in atmospheric temperature I
propose (in the case of steam or of any other fluid or gas where pressure may be
due to the amount of heat to which it is subjected) to enclose the upper part of the
gauge, viz., that containing the air and mercury, in a second vessel or jacket suitably
constructed of glass and metal, through which the steam or other fluid shall circulate,
thus keeping the contained air and mercury at the same temperature as the fluid
where pressure is to be determined., It is at once obvious that as steam at any
given pressure is always at the same temperature all difficulty arising from external
variations of temperature is at once overcome.
Having thus described the nature of my said Invention, and how the same is to
be performed, I wish it to be understood that although I have particularly described
one form of gauge constructed on my principle, that I claim as my Invention, all
forms of pressure or vacuum gauges in which the following principles are combined,
vizt.-
-The use of a spring of air or other suitable gaseous fluid acted upon and
confined in its proper chamber by a piston of mercury, hydrocarbon oil, or other
suitable fluid, such fluid being confined by and the pressure being communicated to
such fluid through the medium of an elastic diaphragm of suitable material. I do
not claim as my Invention either the elastic diaphragm as a communicator of
pressure, or the gaseous spring and fluid piston as the indicator of such pressure,
but confine my claim to any combination of the principles, such combination being
my Invention.
In witness whereof, I, the said William Campbell Eyton, have hereunto set
my hand and seal, this Third day of November, in the year of our Lord
One thousand eight hundred and seventy-seven.
WILLIAM CAMPBELL EYTON. (L.S.)