Improvements in Gauges for Indicating or Registering Pressure or Vacuum.
Year: 1898

page_text: Date of Application, 1st Nov., 1898
Complete Specification Left, 17th July, 1899-Accepted, 26th Aug.,
1899
PROVISIONAL SPECIFICATION.
Improvements in Gauges for Indicating or Registering Pressure
or Vacuum.
I, EMILE HERVAIS, of 9, Rue Saint Sébastian, Paris, in the Republic of France,
Engineer, do hereby declare the nature of this invention to be as follows:
The pressure or vacuum indicating apparatus which forms the subject of this
invention is based upon the application of a metal tube in an extremely flattened
condition which is wound upon itself in such a manner as to form an elastic
This flattened tube
spiral, either plane or conical, having several convolutions.
is placed in communication, by means of its external extremity which is fixed,
with the vessel or the like the pressure existing in which it is desired to measure;
the internal extremity of the tube, which is movable, is fixed directly to the
axis of oscillation of the indicating needle or registering stylus, in such a manner
as to actuate it when the spiral becomes wound or unwound owing to the varia-
tions of pressure within the tube.
For a given variation of pressure, the angular displacement of the movable
end of the tube being proportional to the number of convolutions, it follows
that by a suitable determination of this number, an angular displacement of the
indicating needle or registering part may be obtained which is as great as may
be desired, without recourse to the employment of multiplying mechanism.
The application of my flattened elastic tube having a number of convolutions
permits of the construction of pressure gauges and similar instruments capable
of indicating or registering any variations of pressure, large or small, and abso-
lutely without transmission parts, connections or joints, which on the one hand
injuriously affect the sensibility of the apparatus and which on the other hand
rapidly deteriorate when the apparatus is subjected to oscillations or shocks or
are exposed to humidity or to certain emanations.
In carrying my invention into practice the external extremity of the com-
pletely flattened metal tube wound in a spiral is attached to the tube for the
The other
supply of the fluid the pressure of which it is desired to measure.
extremity of the flattened tube is fixed to a socket which supports the axis of
the indicating needle.
.
The dial may be marked in the usual manner by employing a standard pressure
gauge. If, however, in the case of a dial which has been marked beforehand,
the divisions do not correspond to the displacement of the needle, these latter
may be readily modified in such a manner as to cause them to conform to the
indications upon the dial.
It will be
For this purpose I employ a slide embracing two convolutions.
understood that it is only necessary to change the position of the slide, by causing
it to move along the convolutions, in order to cause a variation of the angular
displacement of the needle corresponding to a given difference of pressure; it
will thus be seen that the adjustment of the apparatus is extremely simple.
This form of pressure gauge being free from any transmission part between

page_text: the tube and the needle, may be employed, and have a long life, in many cases
in which an ordinary pressure gauge would not stand, either owing to its being
submitted to shocks, or exposed to humidity or to emanations which would
modify the articulations and delicate parts.
As an example of the applications of my pressure gauge I will cite its adapta-
tion to a pump for the inflation of pneumatic tyres;
The arrangement described is applicable not only for the construction of
pressure gauges, but also for the construction of vacuum indicators. In this
case the tube is not completely flattened; a small space is left between its
walls in order to enable the atmospheric pressure exerted externally to produce
the deformation of the section of the tube.
For apparatus for registering pressure or vacuum, the indicating needle is
replaced by a part carrying the stylus.
The flattened tube is wound in a conical or flat spiral thus forming a path of
considerable length with a very small volume and weight; it is especially applic
able for dynamometric indicators intended for tracing diagrams. Indicators
thus formed are free from the defects of ordinary indicators arising from the
inertia and friction of the pistons. For this class of apparatus the tube is
arranged so as to become deformed in both ways; pressure or vacuum.
The arrangement of my indicators or registering apparatus for pressure or
vacuum may be reversed, that is to say, the internal extremity of the spiral may
be fixed and connected with the vessel or the like of which it is desired to
measure the pressure, the outer extremity being movable and attached to the
indicating or registering part.
Dated this 1st day of November 1898
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements in Gauges for Indicating or Registering Pressure
or Vacuum.
I. EMILE HERVAIS, of 9, Rue Saint Sébastian, Paris, in the Republic of France,
Engineer, 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:-
-
The pressure or vacuum indicating apparatus which forms the subject of this
invention is based upon the application of a metal tube in an extremely flattened
condition which is wound upon itself in such a manner as to form an elastic
spiral, either plane or conical, having several convolutions. This flattened tube
is placed in communication, by means of its external extremity which is fixed
with the vessel or the like the pressure existing in which it is desired to measure;
the internal extremity of the tube, which is movable, is fixed directly to the
axis of oscillation of the indicating needle or registering stylus, in such a manner
as to actuate it when the spiral becomes wound or unwound owing to the varia-
tions of pressure within the tube.
For a given variation of pressure, the angular displacement of the movable
end of the tube being proportional to the number of convolutions, it follows
that by a suitable determination of this number, an angular displacement of the
indicating needle or registering part may be obtained which is as great as may
be desired, without recourse to the employment of multiplying mechanism.

page_text: The application of my flattened elastic tube having a number of convolutions
permits of the construction of pressure gauges and similar instruments capable
of indicating or registering any variations of pressure, large or small, and abso-
lutely without transmission parts, connections or joints, which on the one hand
injuriously affect the sensibility of the apparatus and which on the other hand
rapidly deteriorate when the apparatus is subjected to oscillations or shocks or
is exposed to humidity or to certain emanations.
In the accompanying drawing:
Figure 1 is
vertical section of a pressure-gauge embodying my invention.
Figure 2 is a horizontal section of same through line CD of Figure 1.
Figure 3 is a front view of same.
Figure 4 is an enlarged view intended to more clearly show the shape of the
flattened tube in cross section.
Figure 5 shows the mode of securing the tube to the central socket which is
fixed to the axis of the indicating needle.
Figure 6 illustrates the application of my pressure gauge to a pump for inflat-
ing pneumatic wheel-tyres."
In carrying my invention into practice the external extremity a of the com-
pletely flattened metal tube A wound in a spiral is attached to the tube for the
supply of the fluid the pressure of which it is desired to measure. The other
extremity of the flattened tube is fixed to a socket B which supports the
axis D of the indicating needle E.
The dial may be marked in the usual manner by employing a standard pressure
gauge. If, however, in the case of a dial which has been marked beforehand,
the divisions do not correspond to the displacement of the needle, these latter
may be readily modified in such a manner as to cause them to conform to the
indications upon the dial.
For this purpose I employ a slide C which consists of a metallic blade pro-
vided with a groove for the passage of the axis D of the needle and bent down
at its end c'. By turning such slide C round while it freely slides, its end c¹
can be brought close to any desired point of the spiral A, after which it is fixed
in position on the socket B by means of the nut c².
As only the portion of the spiral which is comprised between the points a
and cacts to displace the needle, it is obvious that you have but to change the
position of the slide to make different the angular displacement of the needle
for a given change in the pressure it is desired to measure. It will thus be seen
that the adjustment of the apparatus is extremely simple.
This form of pressure gauge being free from any transmission part between
the tube A and the needle, may be employed, and have a long life, in many
cases in which an ordinary pressure gauge would not stand either owing to its
being submitted to shocks, or exposed to humidity or to emanations which would
modify the articulations and delicate parts.
As an example of the applications of my pressure gauge I will cite its adapta-
tion to a pump for the inflation of pneumatic tyres; (see Figure 6).
The arrangement described is applicable not only for the construction of
pressure gauges, but also for the construction of vacuum indicators. In this
case the tube is not completely flattened; a small space is left between its
walls in order to enable the atmospheric pressure exerted externally to produce
the deformation of the section of the tube.
For apparatus for registering pressure or vacuum, the indicating needle is
replaced by a part carrying the stylus.
The flattened tube is wound in a conical or flat spiral thus forming a path of
considerable length with a very small volume and weight; it is especially applic-
able for dynamometric indicators intended for tracing diagrams. Indicators
thus formed are free from the defects of ordinary indicators arising from the
inertia and friction of the pistons. For this class of apparatus the tube is
arranged so as to become deformed in both ways; pressure or vacuum.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1st. A gauge for indicating or registering pressure or vacuum, consisting of a
metallic tube in a much flattened condition which is wound upon itself in such
a manner as to form an elastic spiral, either plane or conical, having several
convolutions, the outer extremity of such tube being fixed and placed in communi-
cation with the vessel or the like the pressure existing in which it is desired
to measure, while the other extremity is movable and directly connected to the
needle, stylus or other indicating or registering device.
2nd. In a gauge for indicating or registering pressure or vacuum of the above
description, a slide provided at its end with a projection which can be brought
in contact with any desired point of the length of the spiral tube, for the
adjustment of the gauge.
11
LT1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.