Improvements in Apparatus for Testing Gas or Air Mains.
Year: 1890

page_text: Date of Application, 26th Aug., 1890-Accepted, 11th Oct., 1890
COMPLETE SPECIFICATION.
Improvements in Apparatus for Testing Gas or Air Mains.
I, GEORGE MOAT, of Bingham, in the County of Nottingham, Manager of Gas
Works, 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, reference being had to the accompanying drawings and to the
jetters and figures marked thereon, that is to say :-
This invention relates to improvements in syphons or test boxes for gas or air mains
and its object is to greatly facilitate the testing of three-way or four-way mains.
In the accompanying drawings:
Fig. 1 is a plan of a three-way gas main junction test box, and
Fig. 2 is a plan of a four-way gas main junction test box, constructed according to
my invention.“
Fig. 3 is a vertical section of Fig. 2 with the leak indicator attached.
Figs. 4 and 5 are vertical sections showing modified constructions of a three-way
and four-way syphon or test box respectively.
The syphon or test box a, which is sufficiently deep to permit the hydraulic sealing
thereof, is provided in its interior with three or four gas tight radial partitions e, as
shown in Figs. 1 and 2 according to whether the box is constructed for a three-way or
a four-way junction. These partitions do not reach to the bottom of the box a but
extend sufficiently far down to project well into the water when the box is sealed,
otherwise they permit a free and uninterrupted flow of gas. The box a is provided
with the usual lid or cover d which is preferably formed with a central opening or
tube for the water pipe 6 through which the water is introduced into box a, and with-
drawn therefrom when necessary. This water-pipe 6 extends to near the bottom of
the box a and passes preferably through an opening formed at the junction of the
radial partitions e. The cover d is further provided with three or four tubes c, c¹, c², c³,
according to the number of radial partitions the box is provided with. To these tubes
the branches of the leak indicator fare connected during the operation of testing.
The pipe band the tubes e, c¹, c², c³, are provided with gas-tight plugs or caps which are
only removed during the testing as occasion demands.
b
When it is desired to test any of the gas inains the plug or cap of the water pipe b
is removed and the box a filled with water nearly up to the level of the mains as
indicated in Fig. 3. The partitions e projecting well into the water, the box is thus
divided into three or four distinct and separate chambers into each of which terminates
one branch of the mains. It is, of course, to be understood that the neighbouring box
or boxes of the main or mains to be tested must also be thus sealed. Supposing that
the main g is the live main, i.e. the one in connection with the gasometer, the cap or
plug of the tube c is removed and one of the branches of the leak indicator connected
in the usual manner. When it is desired to test the main i, the other branch of the
leak indicator is connected to the tube c¹; for testing the main the second branch of
the leak indicator is connected to the tube c² as shown in Fig. 3; and, for the main k,
to the tube c³. The tap or cock of the leak indicator f is then opened and the index
finger of the indicator will then either pronounce the main sound by remaining
stationary, or indicate a leak in the usual manner.
In order to permit the testing of the branch pipe or pipes and to permit the gas still
to flow or pass uninterruptedly through the main trunk pipes, the partition e¹, as
indicated in Fig. 4, is constructed somewhat shorter than the partitions e, in the three-
way syphon or test box, so that by filling the latter with water up to the level shown
in Fig. 4 the gas will still pass underneath the partition e¹ from the main 9 to h, or
vice versa, while the chamber communicating with the branch i is perfectly sealed by
the partitions e projecting sufficiently far into the water.

page_text: To effect the same purpose in a four-way syphon, the central opening at the junction
of the radial partitions, through which the water-pipe 6 passes, is constructed somewhat
larger, and an opening is formed on each side of it, below the level of the main pipes,
and communicates with the chambers of the main trunk pipes, so that by filling the
box with water up to the level of these openings 7, the chambers of the branch i, k, will
be sealed while the gas will still pass from the main pipe g, to h, or vice versa, through
the openings 1, and round the water pipe b. If desired, two of the radial partitions may
be constructed somewhat shorter than the other two, so that, if necessary, one branch
only may be sealed.
When it is desired to test the mains, the test box in each case is filled with water
up to the level of the mains as usual, when all the compartments or chambers will
be sealed.
After the testing is over the pump is attached to the water pipe b, the water with-
drawn from the box a, and the mains are again ready for use after the caps or plugs
are replaced on the pipe 6 and tubes c, c¹, c², c³.
These test boxes can of course be used to test running mains by simply leaving out
the branch outlets.
Although I have described my invention as applied to gas mains, it is obvious that
it may be applied in like manner to air mains.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In apparatus for testing gas or air mains, the construction and use of syphon or
test boxes provided with radial partitions, such as e, corresponding to the number
of mains to be tested, substantially as described and illustrated in the accompanying
drawings.
2. In a radially divided three-way syphon or test box as herein described for gas or
air mains forming or constructing one of the radial partitions shorter than the others
in order to permit of the uninterrupted flow of gas or air through the main pipes
during the testing operation, substantially as described and shown with reference
to Fig. 4 of the annexed drawings.
3. In a radially divided four-way syphon or test box, as herein described, for gas
or air mains, forming or constructing the central part at the junction of the radial
partitions with a transverse passage or opening situated below the level of the main
pipes and communicating with two opposite chambers of the test box and constructing
two of the radial partitions shorter than the other two, as and for the purpose described
and shown with reference to Fig. 5 of the annexed drawings.
Dated this 26th day of A
1890.
ERNEST DE PASS,
78, Fleet Street, London, Agent for the Applicant.