Improvements in Coating Water Pipes with a Protective Covering of a Tarry Nature and in Machinery for Effecting the same.
Year: 1886

page_text: Date of Application, 18th Nov, 1886
Complete Left, 18th Aug., 1887
Complete Accepted, 25th Oct., 1887
Improvements in Coating Water Pipes with a Protective Covering
of a Tarry Nature and in Machinery for Effecting the same.
We DAVID JOHN RUSSELL DUNCAN and HENRY CHARLES MYLNE both of No. 32
Queen Victoria Street London E.C. Engineers do hereby declare the nature of this
invention to be as follows :-
This invention relates to improvements in coating water pipes with a protective
covering of a tarry nature, and in machinery for effecting the same, and is applicable
to long pipes of large diameter, especially such long pipes as are made of steel
plates.
We employ a tank having a semi circular bottom and of sufficient length and width
to receive the largest pipe we propose to coat. This tank may be horizontal and of
equal depth from end to end but we prefer to make it deeper at one end than the
other.
And on the bottom of the tank we place two or more frames each containing several
rollers so arranged that a pipe laid down in the tank shall rest between two rollers on
each frame and be easily rotated.
And at one end of the tank we build a furnace the flues of which we lead under
and at the sides of the tank, and we provide several openings between these flues and
the chimney in which openings we insert dampers, so that we may regulate the heat
of the tank, by keeping the hot gases from the furnace in contact with the tank during
a longer or shorter time.
Into the tank we put a composition made up of tar and other ingredients in certain
proportions. This composition melted and kept liquid by the furnace mentioned
above.
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11

page_text: The pipe which it is desired to coat is laid on the rollers at the bottom of the tank,
and the positions of the rollers and the depth of the melted composition are so chosen
that only about of the circumference of the pipe inside and outside shall be immersed
in the liquid, the other two thirds being exposed to the cooling action of the air.
The pipe on being immersed is left stationary until it has acquired the temperature
of the melted compound or it may be heated up to that temperature in a suitable furnace
or oven before being immersed in melted compound. It is then rotated on the rollers
so that another part of the circumference is immersed in the compound, that which
was previously immersed being now exposed to the cooling action of the air. And
sometimes we employ a jet or blast of air propelled by a fan or other suitable machine
to play upon the coated pipe and cool it.
And in this manner we continue to rotate the pipe until all parts of the pipe have
been immersed, and further, we continue the rotation giving the pipe any number of
complete rotations according to the thickness of the coating which it is desired to put
on the pipe each part of the pipe being exposed to the air before being again immersed
in the composition, or to the air blast mentioned above.
By this process we are enabled to give to the pipes a coating of any thickness
which may be desirable by immersing each part in turn in the melted composition and
then exposing it to the atmosphere or air blast to cool it and hardon it and by the method
described above we effect this in an economical manner and without having to move
the pipe bodily.
Dated this 18th day of November 1886.

page_text: of a Tarry Nature and in Machinery for Effecting the same.
We, DAVID JOHN RUSSELL DUNCAN and HENRY CHARLES MYLNE both of No. 32
Queen Victoria Street London E.C. Engineers, 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 invention relates to improvements in coating water pipes with a protective
covering of a tarry nature and in machinery for effecting the same, and is applicable
to long pipes of large diameter especially such long pipes as are made of steel
plates.
We employ a tank having a semi circular bottom and of sufficient length and width
to receive the largest pipe we propose to coat. This tank may be horizontal and of
equal depth from end to end but we prefer to make it deeper at one end than the
other.
And on the bottom of the tank we place two or more frames each containing several
horizontal rollers so arranged that a pipe laid down in the tank shall rest between two
rollers on each frame and be easily rotated.
And at one end of the tank we build a furnace the flues of which we lead under
and at the sides of the tank, and we provide several openings between these flues and
the chimney in which openings we insert dampers, so that we may regulate the heat
of the tank by keeping the hot gases from the furnace in contact with the tank during
a longer or shorter time.
Into the tank we put a composition made up of tar and other ingredients in certain
proportions. This composition is melted and kept liquid by the furnace mentioned
above.

page_text: The sort of petroleum known as paraffin oil we find to be suitable. Instead of
powdered chalk we sometines use slaked lime. In either case care has to be taken to
keep the composition thoroughly agitated whilst in use to prevent the solid material
being deposited at the bottom of the tank. When this precaution cannot conveniently
be taken it is better to dispense with the chalk or lime.
The pipe which it is desired to coat is laid on the rollers at the bottom of the tank,
and the positions of the rollers and the depth of the melted composition are so chosen
that only about of the circumference of the pipe inside and outside shall be immersed
in the liquid the other two thirds being exposed to the cooling action of the air.
We use these rollers for resting the pipes on when they are heavy, but if the pipes
are light we find it sufficient to balance them in a chain sling suspended from a crane
and lower them into the composition..
The pipe on being immersed is left stationary until it has acquired the temperature
of the melted compound or it may be heated up to that temperature in a suitable
furnace or oven before being immersed in melted compound. It is then rotated on
the rollers so that another part of the circumference is immersed in the compound
that which was previously immersed being now exposed to the cooling action of the
air. And sometimes we employ a jet or blast of air propelled by a fan or other
suitable machine to play upon the coated pipe and cool it.
And in this manner we continue to rotate the pipe until all parts of the pipe have
been immersed, and further, we continue the rotation giving the pipe any number of
complete rotations according to the thickness of the coating which it is desired to put
on the pipe each part of the pipe being exposed to the air before being again immersed
in the composition, or to the air blast mentioned above.
In the case of a small pipe it may be made to acquire the temperature of the com-
pound by immersing it completely in the composition for a short time. This is easily
done when the pipe is suspended in a sling chain from the crane in the manner above
described.
Afterwards whilst the pipe is still suspended but only partially immersed it is
rotated as already described until it is coated to the desired thickness.
By this process we are enabled to give to the pipes a coating of any thickness which
may be desirable by immersing each part in turn in the melted composition and then
exposing it to the atmosphere or air blast to cool it and harden it and by the method
described above we effect this in an economical manner and without having to move
the pipe bodily.
In order that our said invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a longitudinal and vertical section. Figure 2 is a plan partly in section
and Figure 3 is a transverse vertical section of the apparatus. Figure 4 is an elevation
and Figure 5 is a section of the roller frame.
a is the tank, b is the furnace by which the tank is heated c c are the flues around
the tank, d d are dampers which when raised allow the products of combustion from
the furnace to enter the main flue e and so to pass to the chimney. ff are the roller
frames and ff are the rollers which these frames carry. The dotted lines g¹ g² repre-
sent pipes of different sizes resting on these rollers. When coating small pipes the
roller frames need not be used. The pipes are rotated by hand levers, whether they
be large pipes resting on the rollers or small pipes held suspended from a crane in a
chain sling.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we declare that what we claim is :-
1. The means substantially as described of applying a protective resinous or pitchy

page_text: coating to water pipes consisting in partially immersing the pipes in the heated com-
position and in rotating them progressively so that each part of the pipe in succession
is made to emerge from beneath the heated composition and allowed to cool in order
that the composition may set upon it as herein set forth.
2. The machinery substantially as described for applying a protective resinous or
pitchy coating to water pipes consisting of a tank having a semicircular bottom heated
by a furnace and flues and appliances by which the pipe under treatment can be
supported partially immersed in the composition contained in the tank and admitting
of the pipe being progressively rotated to cause each part in succession to emerge
from beneath the heated composition as herein set forth.
3. The combination of apparatus consisting of the parts a, b, c, d, e and ƒ substan-
tially as described.
4. Coating water pipes with a protective resinous or pitchy coating substantially as
described and consisting of Resin, Pitch, Tar Boiled linseed oil and Petroleum and
with or without powered chalk as herein set forth.
Dated this 17th day of August 1887.
D. J. RUSSELL DUNCAN.
HENRY C. MYLNE.