Improvements in Siphon Test Boxes for Gas Mains.
Year: 1894

page_text: Date of Application, 29th Mar., 1894-Accepted, 5th May, 1894
COMPLETE SPECIFICATION.
Improvements in Siphon Test Boxes for Gas Mains.
I, ADOLPHE BOUVIER of 25 Avenue de Noailles, Lyons, in the Republic of
France, 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 :—
The object of this invention is a siphon test box for detecting leaks of gas.
The apparatus is shown in the annexed drawings, in which
Figure 1 is a vertical section along the axis of the dipping pipe.
Figure 2 is a vertical section along the axis of the dipping pipe and at right
angles to the preceding figure.
Figure 3 is a plan.
In these figures
A is a siphon receptacle or box of metal usually cast iron connected to the gas
main by means of two tubes a a¹.
The inside chamber or box A of the siphon is U shaped as shown being, divided
into two separate parts by a partition a² cast with the box.
B, C, D are three vertical tubes.
Each of these tubes B, C, D receives a pipe marked with the corresponding
small letter bc d. is a pipe fixed in the central tube B. This pipe is a
prolongation of the pipe b. It is bevelled at its lower end which dips to the
bottom of the box A. I call it the dipping pipe. It serves to introduce water
nto the siphon.
The tubes C and D with their respective pipes c d serve for the passage of gas
when testing the tightness of the mains.
E is an inspection box with a cover e beneath which I place my siphon.
F F is the ground line.
fff are screw caps for the pipes b c d having generally a triangular or other
shaped head.
9992 are grease cups which like the caps are preferably of inoxidisable metal.
His a horizontal plate connecting the three tubes B, C, D.
is a similar plate receiving the pipes b c d and which is fixed to the plate H.
I, J are lateral tubes or junction pieces which serve to connect the siphon to
the main.
K is a plug in the bottom of the box.
Leaks are searched for in the following manner :-A given section of the main
comprising part of a street or even several neighbouring streets in the same
quarter being isolated from the rest of the system by means of one or more
siphon boxes previously filled with water, as shown in Figure 1, I bring up a
portable gasometer of ordinary construction mounted on wheels which is not shown
in the drawings.
It is assumed that the pipe a and consequently also the tube C and pipe c
communicate with the side where the gas is supplied freely from the gas works
under the usual daytime pressure of gas, for example 20 millimetres of water, and
that the pipe a¹ and consequently the tube D and pipe d communicate with the
isolated section. I close all the supply branches from this section ceasing therefore
to supply gas to the consumers of this section; this interruption does not last more
than half an hour and only takes place once or twice a year. I connect the supply
The bell of the
pipe of the gasometer by an indiarubber pipe with the pipe c.
gasometer rises owing to its floatation and is filled with gas at a pressure of
20 millimetres. When it is full I close the supply pipe c and connect the exit

page_text: pipe of the small gasometer with the pipe d of the siphon and thus with the section
to be tested. Sufficient weights are placed on the bell to give the gas it contains
a considerable pressure for the test say 100 millimetres.
I introduce this gas under pressure into the isolated section and the bell first
descends a certain distance by reason of this. Afterwards if there are leaks in
this section the bell descends at a rate proportional to the size of the leaks. I note
how many litres of gas escape per minute from each section under the testing
pressure of 100 millimetres. I am thus enabled to know in figures the relative
tightness of each section under conditions which augment the sensibility of the
test and the precision of the measure, I know where the leaks are and their
importance, it is thus easy to repair them.
This siphon test box also serves as an ordinary siphon for receiving the
condensations from the gas as a connecting piece for the mains and as a hydraulic
stop valve for closing the passage for the gas under any circumstances for example
in case of accident, fire or explosion, repairs &c.
Having now particularly described and ascertained the nature of my said inven-
tion and in what mauner the same is to be performed I declare that what I
claim is :-
1. The siphon box substantially as described and shown in the drawings.
2. The combination of these siphons with a system of gas mains for dividing
them into sections which can be completely isolated the one from the other by
introducing water into the siphons.
3. The combination with these siphons of a portable gasometer for the purpose of
testing under pressure for leaks and for exactly measuring their importance.
Dated this 29th day of March 1894.
CARPMAEL & Co.,
Agents for the Applicant.