An Improved Pressure Gauge.
Year: 1890

page_text: Date of Application, 13th Sept., 1890-Accepted, 18th Oct., 1890
An Improved Pressure Gauge.
We ISAAC SMITH, SAMUEL SMITH, and WILLIAM SMITH, Brassfounders, trading.
as Sydney Smith and Sons, Basford Brass Works, Nottingham, 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:-
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a front view of one of our improved pressure gauges, with the spring
case and springs shown in section.
Figure 2 shows an underside view of the upper half of the spring case, and an
upper spring.
Figure 3 shows a plan of the lower half of the case and a lower spring.
Each pressure gauge consists of a circular hollow metal case A provided interiorly
with bearing plates in which an axle pin B rocks, the axle pin carries a small toothed
pinion wheel, which gears into the teeth of a metal quadrant projecting from an axle.
pin rocking in bearings within the case, the tail of the toothed quadrant being hinged
to one end of a short link having its other end hinged to the upper end of a rod
terminating at the bottom in a ball C.
The ball C fits into the upper end of a stud C³ forming a ball and socket joint in"
the usual way, see Figures 1 and 2. The lower part of the stud forms the centre of
a volute spring D, usually employed in pressure gauges, the outer coil of which rests
on an upper seat D' cut in the underside of the upper part of a metal case D² which
projects from the bottom of the hollow metal case A.
Beneath the spring D we place an additional volute spring E, which we terin the
load spring, the outer coil of which rests on a lower seat E also cut in the underside
of the upper half of the metal case D2, the central coil of the spring terminates in a
stud E². And beneath the load spring we place a flat disk of vulcanized indiarubber F
the edge of which lies in a recess cut in the upper side F1 of the lower part of the
metal case D2, the edge of the disk being firmly clamped between the two parts of
the case by screws passed through the flanges.
The lower part of the case D may be formed either square, hexagonal or octagonal
in shape at D³, and terminate with a short pipe D scrow threaded exteriorly as
shown at Figure to connect the pressure gauge to one end of a syphon pipe the.
other end of the pipe being attached to the vessel containing the steam, air, water or
other fluid under pressure.
The front of the hollow metal case A is provided with a dial having two scales G
and H, the inner scale G showing the number of pounds pressure per square inch,
and the outer scale H showing the number of feet of water in a column.
The front end of the axle pin B carries a hand B¹ for indicating the pressure and
the height of a column of water or other fluid.
The hand and dial are covered with a sheet of glass in the usual way.
The combined action of the spring D and the loading spring E is as follows:-
Both springs when at rest assume the position shown at Figure 1, but upon steam,
air, water or other fluid under pressure being admitted through the pipe D₁ the india-
rubber disk F and the load spring E will be forced upward until the top of the
stud E (when the pressure has reached one hundred pounds per square inch) touches
the bottom of the stud C₁ of the spring D, further pressure causing the stud C¹ to
rise and move the hand B to indicate the pounds pressure per square inch and the
number of feet of water in column.
We have described the loading spring E as requiring a pressure of one hundred
pounds per square inch before the hand B₁ indicates a greater pressure. But we do

page_text: not confine ourselves to a load spring requiring only that pressure as we may employ
loading springs requiring a pressure of from ten pounds per square inch u, to two
thousand pounds or more before the hand commences to indicate, and provide dials
each having two scales figured to indicate the pounds pressure per square inch, and
the number of feet of water in column above the loading pressure of the additional
spring employed.
In pressure gauges so constructed the hand on the dial shown at Figure 1 will
indicate the pressure above the loading pressure of the additional spring employed.
The advantage of our improved pressure gauge consists in being able to indicate
by means of a hand on a dial, the pressure required starting from an already allowed
pressure on the loading spring. By which we are enabled to make the divisions on
the scales of the dial with a greater range, and thus admit of larger figures being
marked on a dial of small diameter.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The employment in pressure gauges of an additional volute loading spring placed
below the spring usually employed to operate the indicating hand. The loading spring
receiving a certain known pressure before the spring usually employed begins to
operate the indicating hand substantially as described and illustrated in the drawings
annexed for the purposes specified.
2. The employment of a loading spring below and in addition to the spring usually
employed to operate the indicating hand of a pressure gauge substantially as described
for the purposes specified.
Dated this Twelfth day of September 1890.
H. W. GOUGH, C.E.,
Agent.