IMPROVEMENTS IN STEAM OR PRESSURE GAUGES
Year: 1879

page_text: LETTERS PATENT to George Salter, of West Bromwich, in the County of
Stafford, Manager of Works, for the Invention of "IMPROVEMENTS IN STEAM
OR PRESSURE GAUGES."
Sealed the 2nd March 1880, and dated the 13th September 1879.
PROVISIONAL SPECIFICATION left by the said George Salter at the Office
of the Commissioners of Patents on the 13th September 1879.
GEORGE SALTER, of West Bromwich, in the County of Stafford, Manager of
Works. "IMPROVEMENTS IN STEAM OR PRESSURE GAUGES."
My Invention has reference to steam or pressure gauges, in which the steam or
other fluid or liquid, the pressure of which is to be measured, communicates with the
interior of a flat tube curved into a nearly semi-circular figure, the said curved tube
tending to straighten itself under the pressure.
In the ordinary method of constructing steam or pressure gauges of this kind the
free end of the curved flat tube is connected by a link or connecting rod to the short
arm of a lever, the long arm of which carries a toothed quadrant which gears with
a pinion on the axis of the indicating finger. The motion of the free end of the
tube under the influence of pressure within the tube communicates motion through
the parts described to the indicating finger.
Or the link or connecting rod on the free end of the curved flat tube is jointed to
a slotted arm fixed on the axis of the indicating finger, the said indicating finger
in this arrangement being excentric to the axis of the case of the gauge.
In constructing one of the said steam or pressure gauges according to my
Invention I dispense with the toothed quadrant and pinion and connecting link or
connecting link and slotted arm described, and employ the following arrangement
of parts for communicating the motion of the free end of the curved flat tube to the
indicating finger :-Near the free end of the tube I fix an axis, the said axis being
secured to the back of the case of the gauge. Upon the said axis I place a short
cylinder or bush, the said cylinder or bush turning freely on the said axis.. The
underside of the said bush has a deep groove in it, the said groove having the
position of a radius. To the free end of the tube an arm is fixed, the said arm
carrying at its end a pin which takes into the radial groove on the underside of the

page_text: bush. In the normal position of the tube the pin carried by it is situated in that
part of the groove near the margin of the bush. The end of the tube in moving
under the influence of pressure in its interior describes a path nearly in the direction
of a tangent to the bush. In consequence of this motion in the end of the tube
the pin carried by it and engaged in the slot in the bush gives motion to the bush
upon its axis, the said bush slightly changing its position in the slot as the bush
travels through the angle to which its motion is limited. The upper or outer side
of the bush protrudes through a hole in the dial plate, and is made square for the
reception of the indicating finger, which is fixed on the bush by a screw and screw
nut.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Salter in the Great Seal Patent Office on the 4th March
1880.
GEORGE SALTER, of West Bromwich, in the County of Stafford, Manager of
Works. "IMPROVEMENTS IN STEAM OR PRESSURE GAUGES."
My Invention has reference to steam or pressure gauges in which the steam or
other fluid or liquid, the pressure of which is to be measured, communicates with
the interior of a flat tube curved into a semi-circular figure or other curved figure,
the said curved tube tending to straighten itself under the pressure.
In the ordinary method of constructing steam or pressure gauges of this kind the
free end of the curved flat tube is connected by a link or connecting rod to the sbort
arm of a lever, the long arm of which carries a toothed quadrant which gears with
a pinion on the axis of the indicating finger. The motion of the free end of the
tube under the influence of pressure within the tube communicates motion through
the parts described to the indicating finger. Or the link or connecting rod on the
free end of the curved flat tube is jointed to a slotted arm fixed on the axis of the
indicating finger, the said indicating finger in this arrangement being excentric to
the axis of the case of the gauge.
In constructing one of the said steam or pressure gauges according to my
Invention I dispense with the toothed quadrant and pinion and connecting link, or
connecting link and slotted arm described, and I employ the following arrangement
of parts for communicating the motion of the free end of the curved flat tube to the
indicating finger :-Near the free end of the tube I fix an axis, the said axis being
secured to the back of the case of the gauge. Upon the said axis I place a short
cylinder or bush, the said cylinder or bush turning freely on the said axis. The
underside of the said bush has a deep groove in it, the said groove having the
position of a radius.. To the free end of the tube an arm is fixed, the said arm
carrying at its end a pin which takes into the radial groove on the underside of the
bush. In the normal position of the tube the pin carried by it is situated in that
part of the groove near the margin of the bush. The end of the tube in moving
"

page_text: under the influence of pressure in its interior describes a path nearly in the direction
of a tangent to the bush. In consequence of this motion in the end of the tube the
pin carried by it and engaged in the groove in the bush gives motion to the bush
upon its axis, the said pin slightly changing its position in the groove as the bush
travels through the angle to which its motion is limited. The upper or outer side
of the bush protrudes through a hole in the dial plate for the reception of the indi-
cating finger, which is fixed on the bush by a screw and screw nut or otherwise.
I will now proceed to describe with reference to the accompanying Drawing the
manner in which my Invention may be performed.
Figure 1 represents a front elevation, and Figure 2 a horizontal section of a
steam or pressure gauge containing my improvements; Figure 3 is an elevation,
partly in vertical section, of the same with the glass covering dial plate and indi-
cating finger removed; Figure 4 is a side elevation and plan of the short cylinder
or bush of the transmitting mechanism detached; and Figure 5 represents a side
elevation and edge view of the free end and arm of the curved flat tube of the gauge
detached.
The same letters of reference indicate the same parts in Figures 1, 2, 3, 4,
and 5.
'
a is the flat curved tube situated within the case of the gauge, the interior of
the said tube a being put into communication with the steam or other fluid or
liquid to be measured in the usual way; b is the graduated dial plate of the gauge ;
and c is the indicating finger traversing the dial of the dial plate b; e is the axis of
the transmitting mechanism fixed to the back of the case of the gauge. Turning
upon the said fixed axis e is a short cylinder or bush f, the hole in the middle of
the said bush fitting loosely on the said axis e; the bush f is thereby capable of
rotating with great freedom upon the axis e. The cylinder or bush f is preserved
in its place upon the axis e by the free end of the tube a, as herein after explained.
In the back of the bush f is a deep groove or slot g, having the position of a radius,
but for convenience of manufacture may extend across the bush as a diameter, as
represented in the Drawing. To the free end of the curved tube a an arm h is
fixed (see Figure 5), the said arm having at its end a pin i which takes into the
groove g in the back of the bush f, as best seen in the section of the bush, Figure 3.
By the engaging of the pin i on the arm h with the slot g in the bush f the said
bush is kept in its place on the axis e, but is capable of rotating upon the said axis.
The indicating finger c of the gauge is connected to and partakes of the motion of
the bush f, the said indicating finger c being secured to the said bush by a square
part of the said finger fitting upon a square collar k at the top of the bush, the said
square part of the bush protruding through the dial plate b, and by means of a
screw nut screwing upon the end of the axis e the indicating finger c is fixed in
its place.
When the curved tube a is in its normal position that is not under the influence
of steam or other pressure to be measured, the pin i on the arm h at the free end
of the said tube is situated in that part of the groove g near the margin of the
bushf. When however the tube a is put into communication with the steam or
pressure to be measured, the said tube tends to straighten itself as is well under-
stood, its end describing a path nearly in the direction of a tangent to the bush f.
As the free end of the tube a takes the motion described, the pin i carried by the
arm hand engaged in the groove or slot in the bush f, gives a motion through
the required angle to the said bush f upon its axis e. As the bush ftravels through
the angle to which its motion is limited by the change of Figure of the end of the
tube a, the pin i moves in the slot or groove g towards the axis e. The motion
thus given to the bush fis transmitted to the indicating finger c fixed to it, which
finger traverses the dial band indicates therein the pressure of the steam or other
fluid or liquid pressure within the tube a.
:
The pin on the arm h may be made adjustable so as to regulate with great
nicety its position in the groove g of the bush.
Figure 6 represents in elevation and Figure 7, in horizontal section a gauge

page_text: constructed according to my Invention, in which the pin is made adjustable as
last described; Figures 8 and 9 represent the parts of the arm of the tube.
In this arrangement, the arm at the free end of the curved tube a is made in
two parts marked respectively m and n. The part m is shown separately in
Figure 9, and the part n connected with the curved tube a, is shown separately
in Figure 8. The part m carries the pin i which engages with the groove g in the
bush fand the part n is furnished with a slot in which a guide stud p on the other
part m works. After the position of the pin i has been adjusted by sliding the
two parts m, n, upon one another, the said parts are fixed together in the adjusted
position by passing a screw pin q through the slot in the part n and through a
holes in the other part m as illustrated in the Drawing.
In Figure 7 the bush is omitted but is indicated in dotted lines in Figure 6.
My Invention is also applicable to steam or pressure gauges in which the flat
tube has a nearly circular figure, or other curved figure instead of the nearly semi-
circular figure represented in the Drawing.
Having now described the nature of my Invention, and the manner in which
the same is to. be performed, I wish it to be understood that I claim as my
Invention of improvements in steam or pressure gauges of the kind described,-
The construction and combination of the parts herein before described and
illustrated in the accompanying Drawing for communicating or transmitting the
motion of the free end of the curved tube of the gauge to the indicating finger of
the said gauge; that is to say, the construction and combination of the grooved or
slotted bush f, g, k, turning on the fixed axis e with the arm and stud h, i, (or the
adjustable stud described and represented) on the free end of the curved tube, the
said stud i engaging in the groove in the bush and communicating or transmitting
the motion of the free end of the curved tube to the indicating finger, substantially
as described and illustrated.
In witness whereof, I, the said George Salter, have hereunto set my hand
and seal, this Twenty first day of February, in the year of our Lord One
thousand eight hundred and eighty.
Witness,
J. H. BIRCH.
Handsworth.
GEORGE SALTER. (L.S.)