CERTAIN IMPROVEMENTS IN APPARATUS FOR MEASURING THE PRESSURE OF AIR, STEAM, GAS, AND LIQUIDS
Year: 1853

page_text: COMPLETE SPECIFICATION filed by Theodore Benoit Warée at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 13th October 1853, pursuant to the 9th Section.
of the Patent Law Amendment Act, 1852.
I, THEODORE BENOIT WAREE, of Paris, in the Empire of France, and
of 16, Castle Street, Holborn, (City,) London, do hereby declare the
nature of the said Invention for "CERTAIN IMPROVEMENTS IN APPARATUS
FOR MEASURING THE PRESSURE OF AIR, STEAM, GAS, AND LIQUIDS," to be as
follows, viz.
Fig. 1, of the annexed Drawings is a plan, and Fig. 2, is a section
(in the line a, y, of Fig. 1). A, is a plate, having a circular eccentric-
groove to receive the rim of a copper cap B, and which is fixed into it..
The surface of the cap is slightly convex; and the edge rounded, so that
when the vacuum is made in the interior. the convex and circular parts
in the circumference of the cap cause a greater displacement, that is to.
say, descend more than if the cap were cylindrical, as this cap could.
not. (in consequence of its thinness) after having been submitted to the
atmospheric pressure resume its original position if the pressure ceased.
I have placed under the cap at its centre a spiral spring. c, strong
enough to raise it; this spring is retained on-the-plate A, in a small

page_text: cavity, and at its upper part it is held by a piece soldered to the centre
of the cap, and which rests within the spring. This piece projects slightly
beyond the cap, and has a division to allow the passage of a watch
chain hook, which is held by a pin traversing the groove in an opposite
direction. This chain passes through an aperture made above it in the
bridge P, the fect of which are screwed to the plate A. Upon this
bridge (which is arranged so as to receive the whole mechanism) is
placed a small bridge R, having a very sensitive pulley over which the
chain passes, and returns at right angles by means of a double link, so
that instead of being flexible vertically it is so horizontally. This chain
afterwards encircles a portion of pulley which is fixed by two screws on
the wheel D. Its extremity is supported by another screw placed on the
flat part of the pulley. The wheel D, which carries a portion of the
pulley, has one hundred teeth, and gears with a ten-toothed pinion E,
fixed on the axis of the wheel F, of ninety teeth, and which gears with
the ten-toothed pinion H, upon the axis of which is placed the wheel
G, of eighty teeth, which gears with the fen-toothed pinion K. The
latter is fixed on the axis which bears the needle of the barometer,
and is placed in the centre of the plate A, and its axis passes through
the little plate R', in order that the needle may be fixed to it. To this
last pinion the end of a spiral spring is fixed by a collar and pin; the
other end of the spring is held by a ring screw fixed on the plate R.
The spiral spring is wound up by giving it a few turns, and it then
acts on the wheel D, which carries the chain communicating with the
cap, which is slightly raised by the spiral spring, the force of which, by
the intervention of gearing wheels and pinions, is increased about 720
times. Thus, the least movement of the cap caused by the changes of
atmospheric pressure, the vacuum being made in the interior, the last
pinion, that which bears the spiral spring and the needle, will turn to
the right if the cap be depressed, and to the left in the contrary sense.
The sensitiveness of the apparatus will be proportionate to the number
given above; that is to say, it will require on the 720th part of a turn
of the wheel D to effect a whole turn of the pinion K. To regulate
the barometer the part of the pulley over which the chain passes must
be moved towards the centre of the wheel D, if it has not sufficient

page_text: motion, and moved towards, the circumference in a contrary case; for
this purpose this piece is fixed by two screws in a slot M, which allows
it to advance and recede.
Other combinations wheels, pins, and chains, may be used, besides
the one above indicated. This apparatus can also be applied to mano-
meters by means of a tube so arranged on the plate A, as to conduct
steam or other fluid, the pressure of which it is desired to measure, into
the cap B. The spring C, instead of being placed in the interior of
the cap, should be outside, and should rest one side on the centre
of the cap, and the other under the plate R'. The other portions of
the apparatus are not changed, but the thickness of the cap and the
strength of the spring should be proportionate to the pressure of the
steam or fluid to be measured.
I claim the arrangement of apparatus above indicated for the pur-
pose of measuring the pressure of air, steam, water, and any other
liquid or gas.
In witness whereof, I, the said Theodore Benoit Warée, have here-
unto set my hand and seal, this Tenth day of October, in the
year of our Lord One thousand eight hundred and fifty-three.
T. B. WARÉE. (L.s.)