AN IMPROVEMENT IN GUAGES FOR ASCERTAINING THE PRESSURE OF STEAM AND OTHER FLUIDS
Year: 1854

page_text: Sealed the 26th January 1855, and dated the 29th November 1854.
PROVISIONAL SPECIFICATION left by the said Sydney Smith at the
Office of the Commissioners of Patents, with his Petition, on the
29th November 1854.
I, SYDNEY SMITH, of Hyson Green Works, near Nottingham, do hereby
declare the nature of the Invention for "AN IMPROVEMENT IN GUAGES FOR
ASCERTAINING THE PRESSURE OF STEAM AND OTHER FLUIDS" to be as follows:
This Invention consists of applying a flat coiled spring above the vulcanized
india-rubber or flexible diaphragm, or partition of guages, for ascertaining the
pressure of steam and other fluids; by which combination, when the flexible
diaphragm or partition is pressed on, and rendered convex outwards, it will
press the flat spring also into a convex form outwards, and thus by the ordinary.
rack bar give motion to the index.hand.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Sydney Smith in the Great Seal Patent Office on the
23rd May 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SYDNEY
SMITH, of Hyson Green Works, near Nottingham, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of November, in the year of our
Lord One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Sydney Smith, Her special licence that I, the said Sydney Smith, my
executors, administrators, and assigns, or such others as I, the said Sydney
Smith, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "AN IMPROVEMENT IN GUAGES FOR
ASCERTAINING THE PRESSURE OF STEAM AND OTHER FLUIDS," upon the condition
(amongst others) that I, the said Sydney Smith, by an instrument in writing
under my hand and seal, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Sydney. Smith, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof (that is to say):-
This Invention consists of applying a flat coiled spring above the vulcanized
-india-rubber or flexible diaphragm, or partition of guages, for ascertaining the
pressure of steam and other fluids; by which combination,-when-the.flexible
diaphragm or partition is pressed on and render convex outwards, it will
press the flat spring also into a convex form outwards, and thus by the
ordinary rack bar give motion to the index hand.
"
Having thus stated the nature of my said Invention, I will proceed to
describe the manner of performing the same.
'
-
Figure 1 shows a front view, partly in section, of a pressure.guage, con-
structed or combined according to my Invention; Figure 2 shows a side-view,

page_text: partly in section, and Figure 3 shows a plan, of the flat coiled spring used.
In each of these Figures the same letters are used to indicate similar parts.
a is a circular graduated dial; b is the index or pointing hand on the axis c,
which receives motion in the following manner-d is a toothed wheel or
pinion fixed on the axis c; and e is a rod, having a toothed rack e¹ formed at
its upper end; the teeth of this rack take into and drive the toothed wheel d.
The rod e is guided by the groove wheel or pulley g, and the axis c is supported
in bearings c¹, as shewn. h is a flexible diaphragm, which I prefer to be of
vulcanized india-rubber, but other materials may be used. These parts and
their combination are very similar to pressure guages heretofore used, and are
not therefore claimed separate from their combination with a flat spring i,
which is, in the case j, above the diaphragm, and held in the case at its
circumference, as is shewn. The lower end of the rod e enters by its foot e*
into the centre of the coil, and also rests on the upper surface of the coil.
The flat coiled spring is preferred to be made in the first instance slightly
convex downwards, as shown, but this is not essential. When the pressure of
steam or other fluid takes place on the under surface of the diaphragm, it forces
the coiled spring upwards, so as to make it convex upwards, and thus is the
rod e caused to rise and to give motion to the axis, and the pointer 6 fixed
thereon, and thus will the pressure be pointed out on the dial.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that what I claim is, the
application of a flat coiled spring to the flexible diaphragm of a pressure guage,.
as herein explained.
In witness whereof, I, the said Sydney Smith, have hereunto set my
hand and scal, this Twenty-first day of May, in the year of our Lord
One thousand eight hundred and fifty-five.
Witness,
JOHN THOMPSON BREWSTER,
Solr, Nottingham.
SYDNEY SMITH. (L.S.)