IMPROVEMENTS IN INSTRUMENTS FOR MEASURING THE PRESSURE AND TEMPERATURE OF AIR, STEAM, AND OTHER FLUIDS
Year: 1853

page_text: LETTERS PATENT to Charles Léon Desbordes, of Paris, in France,
Engineer, for the Invention of "IMPROVEMENTS IN INSTRUMENTS FOR
MEASURING THE PRESSURE AND TEMPERATURE OF AIR, STEAM, AND
OTHER FLUIDS."
Sealed the 20th October 1853, and dated the, 25th April 1853.
PROVISIONAL SPECIFICATION left by the said Charles Léon
Desbordes at the Office of the Commissioners of Patents, with
his Petition, on the 25th April 1853.
I, CHARLES LÉON DESBORDES, do hereby declare the nature of the
5 said Invention for "IMPROVEMENTS IN INSTRUMENTS FOR MEASURING THE
PRESSURE AND TEMPERATURE OF AIE, STEAM, AND OTHER FLUIDS," to be as
follows:-
I employ a piston and cylinder and a spring to measure the pressure
of steam or other fluids in the following manner. A diaphragm of
vulcanized caoutchouc, or other suitable flexible material, is placed

page_text: across the cylinder to prevent the passage of the fluid, and the piston
rests upon it. The piston is fitted loosely to the cylinder, so as to
move with very little friction. A plain steel spring, supported at one
or both ends, is placed over the end of the piston, or a rod fixed to the
piston, and on this steel spring rests a lever, which gives motion by a
chain or wheels or other means to an index. By employing a plain,
straight, or slightly curved spring, the action of the instrument is
rendered more permanently correct than with any other form of spring
which I have tried. By placing a disc or piston under the caoutchouc
diaphragm, and attaching the two pistons together with the diaphragm
between them, and attaching the end of the piston rod to the spring,
the instrument serves as both a pressure gauge and a vacuum gauge, for
measuring temperatures...I cinploy a bulb and tube filled with
mercury, air, or other fluid, and connected by its tube to an instrument
similar to that above described. The dilatation of the fluid with changes
of temperature is thus measured. Another form of thermometer consists
in the application of a bulb and tube having a shallow circular
box at the end of the tube, which is covered by a flat or slightly dished
or curved plate of copper or steel or other metal. A lever rests upon
this plate, and gives motion to an index as in the first instrument.
Another form of pressure gauge consists of a shallow box covered with
a diaphragm of vulcanized caoutchouc, or other suitable flexible
material, upon which rests a flat plate of steel, which serves as a spring,
and which covers the flexible diaphragm. The motion of the plate is
communicated to an index as before. Another form of vacuum gauge
consists of a shallow box covered with a flat or dished metallic or
other diaphragm, attached to a simple flat steel spring which supports
it. The index is moved as before.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Léon Desbordes, in the Great Seal
Patent Office, on the 24th October 1853.
year
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
CHARLES LEON DESBORDES, of Paris, in France, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of April, in the
of our Lord One thousand eight hundred and fifty-three, in the six-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles Léon Desbordes, Her special
licence that I, the said Charles Léon Desbordes, my executors, admi-
nistrators, and assigns, or such others as I, the said Charles Léon
Desbordes, 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 "IMPROVEMENTS IN INSTRUMENTS FOR MEASURING THE
PRESSURE AND TEMPERATURE OF AIR, STEAM, AND OTHER FLUIDS,"
upon the condition (amongst others) that I, the said Charles Léon
Desbordes, 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 Charles Léon Desbordes, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, reference being had
to the accompanying drawing, and to the figures and letters marked
thereon (that is to say):
This Invention relates to instruments for measuring the pressure and
temperature of air, steam, and other fluids, by means of flexible

page_text: diaphragms in connection with springs and indices, as herein-after
described.
Figure 1, is a front view, and Figure 2, is a section of one of my
improved instruments for measuring the pressure of steam or other
fluids. A, is a plain flat steel spring, fixed in two supports B, B,
attached to the plate C. D, is a piston working in a cylinder X, and
häving a rod H, which rests upon the spring A. E, is a lever, turning
upon a pin e, and carrying a small roller on its shorter arm, which is
in contact with the spring A. A small chain b, is connected to the
longer arm of the lever E, and passed round a pulley c, and atttached
to the spindle, on which a portion of the chain is wound. The spindle
, carries an index L. f, is a small spiral spring, one end of which
is fixed to the spindle d, while the other end is fixed to the back plate C,
by, a support g. This instrument is connected by a flange a, on the
cylinder X, with a pipe leading from a steam boiler; and a disc or
diaphragm of vulcanized caoutchouc is placed in the joint so as to
rest on the flange a, and piston D, and thus prevent any escape of
steam between the piston and the sides of the cylinder. The pressure
of the steam in the boiler depresses the diaphragm and piston, and
deflects the spring A, in proportion to the pressure; and the motion of
the spring is multiplied by the lever E, chain b, and index L, which
indicates the pressure on a graduated dial, or on graduations on the rim
of the box F, which contains the apparatus. When the pressure
diminishes or ceases, the piston is forced up again by the spring A, and
the index is brought back by the spiral spring f. w, w, are a series of
holes in the back plate C, for the purpose of fixing the supports B, B,.at
different distances apart, or for introducing stops or pins for controlling
the motion of the spring A. By this means, the instrument may be
readily adjusted according to the degree of pressure which it is intended
. to measure. The instrument may be placed in the position. shewn in
Figures 1,.and 2, or it may be inverted as shewn in Figure 3, or placed
horizontally, or in any convenient position. It is advantageous to
allow a portion of water to intervene between the steam and the
caoutchouc diaphragm, in order to preserve the diaphragm from the
direct contact of the hot steam.

page_text: ...
If, instead of connecting the pipe from the instŕunient to a steam
boiler, it be connected to a vessel full of compressed air, the instrument
may be employed for measuring the pressure of the air, and in: like
manner it may be employed for measuring the pressure of other fluids.
The mode of communicating, the motion of the spring A, to the
index may be varied. Thus Figure 4; is a front view, and Figure 5,
is a section of another of my improved instruments. Figure 6, is
another section of the same on the line 1, 2, in Figure 5. A, is the
flat metal spring supported by two supports or brackets B, B,
attached to the back plate C, and confined by, two pins w, w. D, is
the piston, and H, is the rod which rests on the spring A, as before.
a, is a little rod carrying a collar' h, and sliding in a support or guide i.
E, is a toothed sector turning on a pin e, and having a short arm, which
comes in contact with the, collar h, being pressed up by the spring f.
The teeth of the sector E, gear into the teeth of the pinion b, on the
spindle d, of the index L, which works over a graduated dial M. I, is
a three way cock in the pipe N, leading to the instrument, which pipe
has a lateral branch O, opening to the atmosphere. The upper part of
the pipe N, communicates with the steam boiler or other vessel
containing the fluid whose pressure is to be determined. By turning
the cock into different positions, the instrument, may be placed in
communication with the atmosphere, or with the vessel containing the
fluid.
My improved instruments may be adapted for vacuum gauges, or for
measuring pressures, below that of the atmosphere, by placing a piston
on each side of the caoutchouc diaphragm, and connecting the two
together, and attaching the piston rod to the flat spring A, which will
then be deflected in one direction when the pressure is less than 'the
atmosphere, and in the opposite direction when it is greater than the
atmosphere.
.
Another of my improved instruments consists of a shallow box
covered with a diaphragm of vulcanized caoutchouc or thin sheet
copper, or other suitable, flexible material, upon which rests a thin flat
plate of steel, which serves as a spring, and which entirely or partially

page_text: covers the flexible diaphragm. The box is connected by a pipe to the
steam boiler or other vessel containing the fluid whose pressure is to be
measured. The motion of the spring is communicated to an index, as
in the other instruments hercin-before described. The flat spring
affords a good support to the flexible diaphragm, which does not there-
fore require to be so thick and strong as would be necessary, if the
spring were only in contact with the diaphragm at a single point. The
flat spring is placed under. the diaphragm, and within the box when
the Instrument is required to measure pressures below that of the
atmosphere. If the box be exhausted of air, and then hermetically
closed, the instrument serves as a barometer for measuring the pressure
of the atmosphere. In this case, the lever or rod by which the motion
is communicated to the index, is made to rest upon the diaphragm itself.
Figures 7, and 8, show two flat springs adapted for being used in
contact with the flexible diaphragm. A series of cuts or divisions are
here shewn in the springs for the purpose of increasing their flexibility.
Their edges are confined or secured to the edge or circumference of
the box.
The measuring temperatures, I employ a bulb and tube filled with
mercury, air, or other suitable fluid, and connected by the tube to an
instrument similar to those herein-before described. The dilatation of
the fluid, or the variation in its elastic force, produced by changes of
temperature, is thus measured. In all my improved instruments, I
employ simple flat springs, which I have found to answer the purpose
much better than spiral springs, or any other springs which I have
tried. These springs may be either quite straight, or they may be
slightly curved or cambered.
Having now described the nature of my Invention, and in what
manner the same is to be performed, I wish it to be understood that I
do not claim generally the application of springs and flexible diaphragms,
for measuring the pressure of fluids. But what I claim is, the con-
struction of instruments in manner herein-before described, for
measuring the pressure and temperature of air, steam, and other
fluids, by means of a flexible. diaphragm, in combination with a plain,

page_text: as herein-before described.
In witness whereof, I, the said Charles Léon Desbordes, have
hereunto set my hand and scal, this Twenty-first day of
October, in the year of our Lord One thousand eight hundred
and fifty-three.
CHARLES LEON DESBORDES. (L.S.)
Witness, JULES MATTIEU,
Ingénieur Civil,
45, Rue St. Sébastien, Paris.