IMPROVEMENTS IN COMBINED PRESSURE AND VACUUM GAUGES
Year: 1885

page_text: We, GEORGE SALTER of the Firm of George Salter and Company of West
Bromwich in the County of Stafford, Manufacturer, and HERBERT AULT of Herbert
Street, West Bromwich, aforesaid, Manager of Works, do hereby declare the nature
of said invention for " IMPROVEMENTS IN COMBINED PRESSURE AND VACUUM
GAUGES," to be as follows:-
Our invention has reference to that class of steam pressure and vacuum gauges
of the Bourdon type, in which the pressure and vacuum is indicated by the
inflection of curved flat tubes fixed at one end and free at the other. The last
named or free end being provided with a link, which is connected to the arm of a
toothed quadrant, which gears with a toothed pinion on the axis of the indicating
finger, so that on the straightening out or dilation of the tube, motion is imparted
to the finger carrying axis; and our said invention has reference to combined
pressure and vacuum gauges where two such curved tubes are arranged concentric
or nearly concentric to each other within a casing or covering behind the usual
dial plate.. The one bent tube which is to indicate pressure forms the outer tube,
while that which is to indicate vacuum forms the inner tube; and each of the
aforesaid tubes embrace nearly a complete circle; that is, there is only com-
paratively a short distance between the fixed and the movable ends of each tube,
thereby imparting great sensitiveness to the gauge, in virtue of the increased
length of curved flat tubing which is brought into requisition; and further, the
compound gauge is capable of indicating up to high pressures, which are unattainable
in gauges of the ordinary construction, where only about a semi-circle of dilatable
tubing is employed.
We will first describe our invention as applied to a combined pressure and
vacuum gauge where the indicating fingers are situated near to each other and in
the same line.
The pressure part of the gauge consists of a flat tube fixed at one end, and
through this end steam or other fluid and liquid passes to the tube. The other or
free end is closed, and is provided with a short arm, to the end of which a link is
connected, which communicates motion to a toothed quadrant supported and
working within a carrying bracket; that is, the link is connected at one end to
the end of the short arm described, which latter passes through a hole in the middle
of the vacuum tube which comes in front of the terminal end of the pressure tube,

page_text: as will be hereinafter fully described. The other end of the link is connected to
the arm below the centre upon which the toothed quadrant turns, while the teeth
of the quadrant gears with the teeth of the pinion on the finger axis.
The vacuum tube which is of less gauge, starts from the opposite side to the
pressure tube, or takes a direction contrary to the pressure tube, thus one takes one
direction and the other takes the other direction, but lying in the same plane and
concentric to each other. The terminal end of the vacuum tube is provided with
an arm as before and a jointed link which is jointed at one end to the arm and the
other to a toothed quadrant above the centre or fulcrum upon which it turns. The
teeth of this quadrant engage with the teeth of a pinion on the axis of an indicating
finger similar to the one with regard to the pressure portion of the gauge. The
axes of these pinions are supported by a bracket which is common to them both.
The gapped or cut away part at the fixed end of the vacuum tube is for the
purpose of allowing the free movement of the arm, on the end of the pressure
tube, or rather to allow the movement of the pressure tube which is outside the
vacuum tube, to communicate its motion to the movements and finger axis within
the inside of the pressure tube. The inside edges of this hole or gap are made
perfectly sound with the tube so as not to impare its efficiency, or weaken the
passage at that part. Instead of the arm passing through a hole or side gap as
described, communication can be made from the outside to the inside of the vacuum
tube, by making the arm cranked or bent, so as to get round the edge of the tube,
instead of passing through it.
Where the pointers or indicators become central, instead of side by side as
described, the teeth of the quadrant arms engage with pinions with the axle of the
one working within a sleeve of the other, like the minute and hour hands of
a clock.
The graduated dial of the vacuum portion of the gauge is arranged within a
concentric circle of the pressure portion of the said dial.
Instead of employing toothed quadrants and pinions, for the communication of
motion, levers may be substituted which are respectively connected to the links;
that is, one lever is connected to an axis carrying a finger, and the other connected
to a sleeve over the axis, so as to allow the working of central pointers or hands
for both vacuum and pressure in that class of gauges called central gauges.
Dated this Twenty fourth day of June 1885
GEORGE SALTER.
HERBERT AULT.
By Henry Skerrett,
6, Livery Street, Birmingham,
Agent to the Applicants.

page_text: Improvements in Combined Pressure and. Vacuum Gauges.
We, GEORGE SALTER of the Firm of George Salter and Company of West
Bromwich in the County of Stafford Manufacturer, and HERBERT AULT of
Herbert Street, West Bromwich, aforesaid, Manager of Works, do hereby declare
the nature of said invention for "IMPROVEMENTS IN COMBINED PRESSURE AND
VACUUM GAUGES," and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
Our invention has reference to that class of steam pressure and vacuum gauges
of the Bourdon type, in which the pressure and vacuum is indicated by tho*
inflection of curved flat tubes fixed at one end and free at the other. The last
named or free end being provided with a link which is connected to the arm of a
toothed quadrant, which gears with a toothed pinion on the axis of the indicating.
finger, so that on the straightening out or dilation of the tube, motion is imparted
to the finger carrying axis, and my said invention bas reference to combined
pressure and vacuum gauges where two such curved tubes are arranged concentric.
or nearly concentric to each other within a casing or covering behind the usual
dial plate The one bent tube which is to indicate pressure forms the outer tube,
while that which is to indicate vacuum forms the inner tube; and each of the
aforesaid tubes embrace nearly a complete circle; that is, there is only com-
paratively a short distance between the fixed and the movable ends of each tube,
thereby imparting great sensitiveness- to the gauge, in virtue of the increased
length of curved flat tubing which is brought into requisition; and further, the
compound gauge is capable of indicating up to high pressures, which are unattain-
able in gauges of the ordinary construction, where only about a semi circle of
dilatable tubing is employed.
We will first describe our invention as applied to a combined pressure and
vacuum gauge where the indicating fingers are situated near to each other and in
the same line.
The pressure part of the gauge consists of a flat, tube fixed at one end, and
through this end steam or other fluid and liquid passes to the tube-The other or
free end is closed, and is provided with a short arm, to the end of which a link is
connected, which communicates motion to a toothed quadrant supported and
working within a carrying bracket; that is, the link is connected at one end to
the end of the short arm described, which latter passes through a hole in the
middle of the vacuum tube which comes in front of the terminal end of the pressure
tube; as will be hereinafter fully described-The other end of the link is connected
to the arm below the centre upon which the toothed quadrant turns, while the
teeth of the quadrant gears with the teeth of the pinion on the finger axıs,

page_text: The vacuum tube which is of less breadth, starts from the opposite side to the
pressure tube, or takes a direction contrary to the pressure tube, thus one takes one
direction and the other takes the other direction, but lying in the same plane and
concentric to each other-The terminal end of the vacuum tube is provided with
an arm as in the before described arrangement and a jointed link which is jointed
at one end to the arm and the other to a toothed quadrant above the centre or
fulcrum upon which it turns-The teeth of this quadrant engage with the teeth of
a pinion on the axis of an indicating finger similar to the one with regard to the
pressure portion of the gauge-The axes of these pinions are supported by a bracket
which is common to them both.
The gapped or cut away part at the fixed end of the vacuum tube is for the
purpose of allowing the free movement of the arm on the end of the pressure tube,
or rather to allow the movement of the pressure tube which is outside the vacuum
tube, to communicate its motion to the movements and finger axis within the inside
of the pressure tube-The inside edges of this holo or gap are made perfectly sound
with the tube so as not to impair its efficiency, or weaken the passage at that
part Instead of the arm passing through a hole or side gap as described, commu-
nication can be made from the outside to the inside of the vacuum tube, by making
the arm cranked or bent, so as to get round the edge of the tube, instead of passing
through it.
'
Where the pointers or indicators become central, instead of side by side as
described, the teeth of the quadrant arms engage with pinions with the axle of
the one working within a sleeve of the other, like the minute and hour hand of a
clock.
The graduated dial of the vacuum portion of the gauge is arranged within a
concentric circle of the pressure portion of the said dial.
Instead of employing toothed quadrants and pinions, for the communication
of motion,. levers may be substituted which are respectively connected to the
links; that is, one lever is connected to an axis carrying a finger, and the other
connected to a sleeve over the axis, so as to allow the working of central pointers
or hands for both vacuum and pressure in that class of gauges called central
gauges.
A
We will now proceed to describe with reference to the accompanying Drawings
the manner in which the same is to be performed..
Figure 1 represents in front elevation a combined pressure and vacuum gauge
(of the Bourdon type, with quadrant and pinion) constructed according to our
invention Figure 2 is the same with the back plate removed, or with the gauge
turned round from front to back in order to exhibit the movements or the
mechanism constituting the gauge, whereby pressure and vacuum is indicated by
the inflection of curved flat tubes of nearly a complete circle-Figure 3 is a trans-
verse section of the vacuum tube which shows clearly the opening through which
the arm or link of the pressure tube passes to impart the motion of the latter to
the pressure pinion axis through the toothed quadrant.
The same letters of reference indicate corresponding parts in figures 1, 2 and 3
of the Drawings.
.
a is the frame or case of the gauge and b is the pressure tube embracing nearly a
complete circle, the said pressure tube which is flat in cross section is fixed at the
end b and provided with au inlet passage 63, while the other or free end b, has a
short arm which passes through an opening c³ in the vacuum tube c; and to the
end of this arm, is a jointed link d, which communicates motion to a toothed
quadrant d supported by a bracket d³, and turning upon a fulcrum centre d'
The teeth of the quadrant arm engage with a toothed pinion e which is on the
pressure indicating finger axis f of the compound gauge, and so indicates; the
pressure through the dilation or opening out of the tube-The vacuum tube c
is affixed in a similar way to pressure tube and has also the same mechanical

page_text: equivalents, or movements for transmitting the dilation of the said vacuum tube
to its indicating finger axis; that is; the entrance end c³ of the vacuum tube is fixed
to the case a, while the free end chas, an arm c³ connected to a link co, which
-latter actuates the toothed quadrant c and which quadrant engages with the teeth
of a pinion g on the vacuum indicating finger axis h-The axes f and h are carried
by the suspending bracket i affixed to the back of the gauge case.
The opening through the vacuum tube of the gauge through which the pressure
arm passes, is made perfectly sound, by soldering or brazing sides c¹ within the
.opening c³ as best seen in longitudinal section figure 4 and transverse section
figure 5 upon an enlarged scale.
By piercing the vacuum tube with an opening as described and represented, the
tube is not materially weakened or its efficiency impaired-Thus the difficulty of
transmitting or communicating the dilation of an outer tube embracing nearly a
complete circle, to its own transmitting movements, and indicating finger axis,
situated within a space enclosed by a second inner concentric tube of a like kind,
is overcome, by having an opening in the latter through which an arm on the end
of the former passes.
In virtue of the increased length of the tubes thus employed, great sensitiveness
is imparted to the gauge; and further, compound gauges provided with extended
tubes, are capable of indicating higher pressures than are attainable in compound
gauges of the ordinary construction, where only about a semi-circle of dilatable
tubing is employed.
Instead of having the hole c* in the middle of the tube c it may with like effect
be gapped out of the side as shown at figure 6, and through this gapped part the
arm on the outside tube passes.
In figure 7 the arm b³ on the end of the pressure tube b, instead of passing
through a hole in the middle of the inside tube c or through a gap in the side
thereof, the said arm bo is made cranked or bent downwards and then upwards, so
as to get round or pass under the edge of the inside tube, instead of passing
through it.
Figure 8 represents in front elevation and figure 9 in transverse section a
compound central hand gauge of essentially the same construction as figures 1 and 2.
other than with respect to the arrangement of the movements which are like those
of an ordinary compound gauge of this type; that is, the finger carrying axes, are
arranged to work one within the other like the minute and hour hand axes of a
clock is the hand for indicating pressure, and its axis-j³ is the pinion on the
said axis which gears with the teeth of the toothed quadrant k-The axis j2 passes
through the sleeve axis of the finger indicating vacuum. 13 is a pinion on the
sleeve l, this pinion 1 gears with the quadrant m which is moved by the dilation
of the vacuum tube c through the link c
Figure 10 shows another form of gauge which is known as an excentric hand
lever gauge, being of essentially the same construction as those hereinbefore
described, other than with respect to the means of communicating motion to the
hand axes.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is
The improvements in combined pressure and vacuum gauges herein before
described and illustrated in the several figures of the drawings; whereby the
dilation tubes b c admit of an increased radius, amounting to nearly a complete
circle, by piercing or gapping the inner tube, in order to admit of the passage
through it of the terminal or transmitting arm on the end of the outer tube. In
virtue of the increased radius thus acquired, compound gauges become more sensitive
and capable of indicating higher pressures, than those of the ordinary kind where

page_text: only about a semi circle of tubing is employed. The parts being constructed,
arranged and carried out in the way and for the purpose substantially as described
and set forth; also the modification described and represented in figure 7 where
the arm on the outer tube is cranked or bent, so as to get round the inner tube.
instead of passing through it.