Improvements in Apparatus for Testing Drain and other Pipes.
Year: 1893

page_text: Date of Application, 7th Sept., 1893
Complete Specification Left, 11th Dec., 1893-Accepted, 17th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Testing Drain and other Pipes.
We WILLIAM TWEEDIE and JOHN TWEEDIE Plumbers 6 Castle Street in the
City and County of Edinburgh do hereby declare the nature of this invention to
be as follows:-
The first part has reference to a plug to be used in testing drains, soil, water
gas, or other pipes. It consists of a hollow piece of rubber in the form of a
cup the mouth end being a little larger and the other end a little smaller than
the pipe to be plugged.
The application is as follows:
-
The cup or plug is turned inside out and passed mouth outwards into the pipe.
It is then pulled back into its normal position by means of a ring or hook
attached to the bottom of the plug. The lip, so to speak, of the cup will then press
against the inner periphery of the pipe & will form with it a perfectly tight
joint with either hydraulic or pneumatic pressure. The plug may have a short
pipe passed through its end with a tap attached for the purpose of injecting
water or air into the pipe to be tested.
The friction between the walls of the plug and the inner surface of the pipe
being sufficient in low pressure only to keep the plug in position it is necessary
to apply some mechanical arrangement with which to keep the plug from being
forced out of position when a high pressure test is applied. The second part
of this invention has reference to an apparatus for this purpose. It consists of
a wood or metal disc slightly smaller in diameter than the pipe to be plugged.
To the centre of the disc moving about a common centre are attached two
hinges which when spread out cover a greater space than the diameter of
the pipe.
The application is as follows:-
The plug baving been adjusted in the pipe in the manner described above, a
disc with hinges attached of the proper size is inserted behind the plug.
The free ends of the hinges are pressed against the sides of the pipe causing
the hinges to assume the form of an arch. The great friction between the ends
of the hinges and the sides of the pipe caused by the thrust of the plug against
the disc will be sufficient to keep the plug in the pipe.
Another mode of securing the plug would be by means of metal or wood
wedges.
Again a disc similar to that already described would be used but instead of
the hinges three quoins or wedges filling the diameter of the pipe would be
employed.
The centre wedge or key would protrude beyond the others on the side of the
disc & plug. The effect of the pressure on the centre wedge would be to drive
the other two apart & against the sides of the pipe. The result being that the
plug would be securely held in the pipe.
5th September 1893.
WILLIAM TWEEDIE.
JOHN TWEEDIE.

page_text: Drain and other ripes.
We, WILLIAM TWEEDIE and JOHN TWEEDIE of 6 Castle Street in the City
and County of Edinburgh, Plumbers, 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 first part refers to a plug to be used in testing drain, soil, water, gas or other
pipes.
Drawings, to make the invention and its application more easily understood, are
annexed.
The plug shewn by A. B and C Figure 1 is made of india rubber in the form of
a cup, the mouth being a little larger and the other end a little smaller than the
pipe to be plugged.
The application is as follows:-
The plug is reversed (turned inside out) and passed mouth outwards into the pipe.
It is then pulled back within itself, by means of a ring attached to its end, into
position. The lip, so to speak, of the cup will then press against the inner periphery
of the pipe, forming with it a perfectly tight joint either under hydraulic or
pueumatic pressure.
The plug, instead of being at first reversed, may be simply placed, mouth
inwards, in the pipe in a collapsed state when, through the elasticity of the rubber,
it will regain its circular form, making the air or water tight joint as before.
Figure 2 shews the position of the plug in the pipe, it having been inserted by
one or other of the methods above described. The pressure from the confined air,
smoke or water is exerted against the inner surface of the plug as shewn by the
arrows.
It may be here pointed out that the principle on which the efficiency of the plug
depends is the same as with the leather collar of the Bramah press. As the
pressure is increased the joint between the wall of the plug and the pipe becomes
the tighter.
Another and simpler application of the plug would be to insert it into a pipe,
taper end first, without reversing it. The tightness of the joint will then, of course,
depend upon the elasticity of the rubber only. With this mode of application the
plug would not keep tight under a high pressure.
The plug may have a short pipe, with a stop cock attached, passed through
its end for the purpose of injecting smoke or water into the pipe which is being
tested.
The friction between the plug and the pipe being sufficient in low pressure only,
to keep the plug in position it is necessary to apply some mechanical arrangement
with which to keep the plug from being forced out of position when a high pressure
is applied.
The second part of this invention relates to an apparatus for this purpose. It
consists of a wood or metal disc slightly smaller than the pipe to be plugged. To
the centre of the disc are attached two hinges or flaps which, when spread out,
cover a greater space than the diameter of the pipe. This apparatus, which for
convenience may be called a bridge, is shewn at A and B Figure 3. The application
is as follows:-
The plug having been adjusted in the pipe, in the manner described above, the
bridge is inserted behind it. The hinges, on their free ends being pressed against
the side of the pipe, will assume the form of an arch.
Figure 4 illustrates the whole arrangement. The great friction between the ends
of the hinges and the pipe, caused by the thrust of the plug against the disc, will

page_text: be sufficient to keep the plug from being forced out of a pipe when under a
considerable pressure.
Another mode of securing the plug in a pipe would be by means of wood or
metal wedges. A disc, similar to that already described, would be used but, instead
of the hinges, three wedges filling the diameter of the pipe would be employed.
The centre wedge or key would protrude beyond the others on the side of the disc
and plug. The effect of the pressure on the centre wedge would be to drive the other
two apart and against the side of the pipe, the result being that the plug would be
held securely in the pipe.
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 :-
1st. The plug substantially as and for the purpose herein before described and
illustrated on the accompanying drawings.
2nd. In holding a plug in a pipe the employment of the bridge substantially as
herein before described and illustrated on accompanying drawings.
Dated this Ninth day of December 1893
WILLIAM TWEEDIE.
JOHN TWEEDIE.