Year: 1899

page_text: 1. JAMES JOIN GUEST, of 19, Trinity Road, Birchfield, Birmingham, Mechanical
and Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention refers to a new or improved pressure gauge & consists of a tube,
the cross section of which is elliptical or other than circular, twisted about its
axis. The corresponding points of the various cross sections then lie upon helices
around the axis of the tube. One end of the gauge tube is connected to the
vessel containing the fluid, the pressure of which it is desired to measure, the
ather end of the gauge tube is closed.
If the axis of the gauge tube is straight, the closed end twists relatively to
the fixed end when fluid pressure is applied. By mounting a pointer or mirror
on the closed end, the amount of twist & hence the pressure, is readily determined.
To eliminate any chance error due to twisting movement of the fixed end,
the scale for the pointer may be mounted on the fixed end.
The amount of twist for a given pressure may be made to be of any convenient
amount by altering the effective length of the gauge-tube.
The axis of the gauge-tube need not however be straight, but may be bent
into a helix, spiral or other convenient form & suitable end pieces attached for
indicating the movement due to the integration of the effect of the twist of
each element of the axis of the tube.
Dated this 8th day of November 1899.
I, JAMES JOHN GUEST, of 19, Trinity Road, Birchfield, Birmingham, Electrical
& Mechanical 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:-
My invention refers to a new or improved pressure gauge & consists of a tube,
the cross section of which is elliptical, or other than circular, twisted about its
axis. The corresponding points of the various cross sections then lie upon
helices round the axis of the tube. One end of the gauge tube is connected to
the vessel containing the fluid, the pressure of which it is desired to measure;
the other end of the gauge tube is closed.
If the axis of the gauge tube is straight, the closed end twists relatively to
DS.11

page_text: the fixed end when fluid under pressure is applied to the interior of the gauge.
By mounting a pointer or mirror on the closed end, the amount of twist &
hence the pressure, is readily determined.
To eliminate any chance error due to twisting movement of the fixed (or open)
end. the scale should be mounted on the fixed end.
The amount of twist for a given pressure. may be made to be of any convenient
amount by altering the effective length of the gauge tube.
The axis of the gauge tube need not however be straight, but may be bent into
a helix, spiral, or other convenient form, & suitable end pieces attached for
indicating the movement due to the integration of the effect of the twist of each
element of the length of the tube.
In Figs. 1. 2 & 3 is shown a gauge, where the axis of the tube is straight & a
nointer is used. ABCDEFGH K is the gauge tube. It is open at the end A
for connection to the vessel containing the fluid whose pressure is to be measured.
It is closed at the other end K. At b c d e f g & h are shown the sections of the
tube at B C D E F G & H respectively. The section indicated is elliptical. The
change of orientation of the section with change of its position on the axis, as
shown at he defa & h indicates the manner in which the tube is twisted about
its axis. W L is the pointer, attached to the closed end K of the gauge. Two
scales, visible from different directions are shown at M & N: these should be
mounted upon the casing P Q fastened to the gauge tube at its open end A.
In Fig. 4. is shown a gauge tube the axis of which is wound into a helix. R is
the open end. The cause S T U is formed of a tube first made like the gauge
Tube ABCDEFGHIK in Fig. 1. & then bent as a whole into the helix (screw
thread) shown in Fig. 4. R S & UV are the end pieces, rending from the end of
the twisted gauge tube to the axis of the helix. R S is tubular to convey the
fluid under pressure to the helical part of the gauge. R & V should be on the
exis of the helix, X is a scale arranged parallel to the axis of the helix & W is
the pointer.
Having now particularly described & ascertained the nature of my said inven-
tion & in what manner the same is to be performed, I declare that what I claim
is:-
A pressure gauge constructed of a tube, the cross section of which is elliptical
or other than circular. twisted about its axis so that the corresponding points of
the various cross sections lie upon helices around the axis of the tube, which
axis may be either straight or curved, the distortion which is observed to deter-
mine the pressure being that due to the integration of the offect of the twist
of the elements of the length of the gauge tube.
Dated this 17th day of January 1900.