An Improvement in Pressure Gauges and Vacuum Gauges.
Year: 1893

page_text: Date of Application, 27th May, 1893
Complete Specification Left, 27th Feb., 1894-Accepted. 25th May, 1894
PROVISIONAL SPECIFICATION.
An Improvement in Pressure Gauges and Vacuum Gauges.
I, THOMAS EVANS MITTON, of 13, 14 and 15, Oozells Street North, in the City
of Birmingham, Engineer's Brass Founder. do hereby declare the nature of this
invention to be as follows:-
This invention has reference to steam and other pressure gauges such as hydraulic
and pneumatic pressure gauges and to vacuum gauges which as usually made have
a flat or bevelled edged glass disc at the front of the numbered dial and indicating
finger. Unless the person examining one of these gauges stands immediately in
front of or but slightly at one side of the gauge, it is difficult to read the numbers
and divisions distinctly as double figures and divisions will be seen through the
bevelled sui face.
This defect I overcome by making one side of the said front glass, preferably
the outside, with a convex surface the other side of the glass being flat concave or
convex. By making the gauge with a front glass of the kind above described, the
necessary thickness of the glass is maintained and there is no confusion of the
numbers and divisions which can be distinctly read even by a person standing very
much on one side of the gauge and looking at the dial obliquely as the peculiar
form of the glass makes the face of the dial appear square with the line of
vision.
Dated this 26th day of May 1893.
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.
COMPLETE SPECIFICATION.
An Improvement in Pressure Gauges and Vacuum Gauges.
I, THOMAS EVANS MITTON, of 13, 14 and 15, Oozells Street North, in the City
of Birmingham, Engineer's Brass Founder, 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 has reference to steam and other pressure gauges such as hydraulic,
pneumatic, gas, or compound pressure gauges and vacuum gauges, which as usually
made have a flat or a bevelled edged glass disc at the front of the numbered dial
and indicating finger. Unless the person examining one of these gauges stands
immediately in front of or but slightly at one side of the gauge, it is difficult to read
the numbers and divisions distinctly as double figures and divisions will be seen
through the bevelled surface of the glass disc.
This defect I overcome by making the said front glass in the form of a lens that
is to say I make the outside with a convex surface the other side of the glass being
flat concave or convex. By making the gauge with a front glass of the kind above
described the necessary thickness of the glass is maintained and there is no
confusion of the numbers and divisions which can be distinctly read even by a
person standing very much on one side of the gauge and looking at the dial
obliquely as the peculiar form of the glass makes the face of the dial appear more
square with the line of vision.

page_text: This will be rendered more clear by referring to the accompanying drawing on
which
Fig. 1 is a part sectional plan of a pressure gauge with the front glass made in
the form of a lens in accordance with this invention and
Fig. 2 shews the same pressure gauge with the dial and indicating finger in the
position which they will appear to occupy when viewed obliquely by a person
standing towards one side of the gauge.
A is the outer casing of the pressure gauge, B is the lens front glass of the same,
C is the indicating finger and D is the dial. When the pressure gauge or vacuum
gauge made in accordance with this invention with a lens having a convex outer
surface is viewed obliquely by a person standing considerably towards one side of
the lens, as for instance at the point E Fig 2, the convex outer surface of the
lens B makes the dial D and indicating finger C appear more square with the line
of vision, that is to say, they appear to take the position in the gauge shewn by
Fig. 2 and the dial can therefore be read more distinctly than is possible when the
front glass is made flat or bevel edged as at present.
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
In pressure gauges and vacuum gauges and in combination with the dial and
indicating finger thereof the employment of a front glass made as a lens so as to
render the reading of the figures on the dial more distinct as hereinbefore set
forth.
Dated this 26th day of February 1894.
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.