Year: 1886

page_text: I, WALTER JOHN THOMAS, of 21 Allendale Road, Denmark Hill, in the county
of Surrey, 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 :-
This improved gauge is designed specially for indicating the pressure of coal gas as
supplied for illuminating purposes, but is applicable with modifications for measuring
the pressure of other fluids.
The ordinary pressure gauge for gas is formed of a glass tube bent U shape, with a
suitable metal tap on the upper ends, which admits the gas to be tested on one side of
the tube, while the atmosphere is admitted to the other.
A coloured liquor is placed in the bend of the tube, and the pressure acting on
this liquor in one side of the tube only, causes the liquor to rise in the other side, and
register the difference of pressure, between the gas and the atmosphere, on a scale
placed on or adjacent to the tube.
In my improved gauge I employ two separate straight tubes of unequal diameter,
one of which I place inside the other.
These tubes may be of glass or of metal with glass panels.
The outer tube must be closed at its lower end when in use, and may be either
made to close with a cap or end piece, or the end may be formed of the glass itself.
This separate cap or end piece has two special advantages over the solid end tube.
It allows the glass tube to be made of any required strength, and it supports a per-
forated ferrule, which holds the end of the inner tube.
It is made air tight by means of a leather or india-rubber washer or by cement.
The inner tube is open at the lower end, which reaches to within a short distance of
the end of the outer tube.
For testing the pressure of gas the usual coloured liquor is placed in the bottom of
the outer tube and forms a seal between the two tubes to be acted on by the gas.
The nature of the liquid forming the seal, can of course be varied according to the
kind of fluid the gauge is designed to register. On the summit of these two tubes is
a special form of tap, having two concentric sockets or projecting ferrules, one inside
[Price Sdl

page_text: the other, into or onto which the two tubes are fitted, and cemented or otherwise
attached.
This tap has two ports or ways one being an inlet for the gas to be tested, which
inlet communicates with the outer tube, and the other an outlet for air, communicating
with the inner tube.
These two ports are opened and closed simultaneously by turning the key, which is
attached to the plug of the tap.
For convenience of attaching my gauge to an ordinary gas pipe, I have designed a
special swivel or knuckle joint, which screws on to either a horizontal or vertical gas
pipe, and suffers the gauge to swing vertically, while the gas enters to be tested.
This joint resembles part of a gas cock, the plug being hollow so that the gas passes
through it to the gauge.
When the gas is admitted into the outer glass tube, the pressure operating on the
coloured liquor causes it to rise in the inner tube.
A scale being attached to this inner tube or placed contiguous thereto, the force of
the pressure is easily shown and recorded.
My improved gauge being cylindrical or of any other preferred shape, and of simple
configuration, is easily enclosed or covered with a metal or other case, which will
effectually protect it from fracture.
This case has several narrow openings or longitudinal slits, so placed that light can
be admitted to the inner tube which can be seen through them, and the scale can be
marked on the sides of one of these apertures, so that the pressure indicated by the
liquor can be conveniently read without removing the case.
My gauge can be made of various sizes and strengths, and can be mounted with
various fittings to adapt it for different kinds and amounts of work.
In the accompanying drawings, the tubes are shown round, but they can be made
oval, oblong, square or of any other shape preferred.
Fig. 1. Shows the gauge with solid glass end.
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2. Shows the same gauge in metal case with scale.
3. Shows the tap and inner tube with ferrules supporting the tube at each end.
4. Shows the outer glass tube open at both ends."
5. Shows a special form of case to be used with the open end outer glass tube.
6. Shows a section of the cap or end piece, which closes the lower end of the
case and outer tube.
7. Shows a cross section of the case with slots for light.
8. Shows a vertical section of the gauge with the special case and cap as in
Figs. 5 and 6.
9. Shows a horizontal section of the special tap enlarged.
10. Shows a vertical section of the swivel joint.
A. is the inner glass tube.
B. is the outer glass tube with enclosed end.
C. is the outer glass tube with open end.
D. is the metal case.
E. is the cap or end piece.
F. is the leather or india rubber washer.
G. is the special tap.
H. is the key of the tap.
I. is the plug of the tap.
J. J. are the ferrules to support the inner tube at each end, the lower ferrule being
perforated.
K. is the inlet for gas.
L. is the outlet for air.
M. is the liquor used for registering the pressure.
N. N. are the slots in the case.
O. is the boss of the swivel joint.
P. is the hollow plug of ditto.
Q. is a projecting stud to receive the end of the lower ferrule J.

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 :-
1. A method of testing the pressure of Gas and other fluids by means of two tubes,
one inside the other, fitted with a scale or register substantially as explained and
set forth.
2. A special form of tap with two ports, having projecting sockets or ferrules, one
inside the other, to receive the aforesaid tubes, as herein explained and set forth.
3. A special swing joint or knuckle for attaching the gauge to ordinary gas pipes
as herein explained and set forth.
4. A metal or other tube with glass panels or glazed slots, with or without an outer
case of metal or other suitable material, perforated with longitudinal slits, to protect
the fragile parts of the gauge from fracture, while permitting the register to be read as
herein described and set forth.
5. A special tube end or cap having a stay or socket for supporting the inner tube
as herein explained and set forth.
S. S. BROMHEAD,
97, Newgate Street, E.C.,
Patent Agent.