Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a method of
insulating a pipe component, e.g. a pipe branch or bend.
In the accompanying drawings:-
Figure l illustrates a previously known insulating
method
Figure 2 is a side view of a mound to be used
in a method embodying the present invention.
Figure 3 is a plan view of the mound.
Figure 4 illustrates an insulated pipe branch
manufactured by means of a method embodying the invention.
Figure 5 is a cross-section of the pipe branch
along the line V-V in Figure 4.
Figure 6 illustrates the area B in Figure 5 on
an enlarged scale, and
Figure 7 (which appears on the same sheet as
Figure l) illustrates a pipe bend manufactured by means
of a method embodying the present invention.
Thermally insulated pipe joints are presently
manufactured, for example, in -the manner illustrated
I in Figure l. A main pipe l usually made of metal is
surrounded at the branching point by a thermal insulation
layer 2 comprising usually a rigid outer layer and a
softer inner layer of foam plastics. Thereafter a hole
is made in the sheath surface of the insulation layer
2. A branch pipe 3 is inserted through said hole and
welded to the edges of an opening in the main pipe l.
Hereafter insulation layer lengths 4, 5 and 6 are pushed
onto the branch pipe and joined -to each other and to the
insulation layer 2 by means of butt welding, manual welding
using a wire or adding a plasticized material to the
seams. This entire operation is very time-consuming,
and often the seams will not be quite tight due to which
moisture may later penetrate into the foam plastic layer.
In addition, the foam plastic is entirely unprotected
at the end of the insulation layer wherefore it may be
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damaged during transport.
The object of the present invention is to provide
a method of insulating e.g. pipe branches and pipe bends
by means of which the work can be carried out quickly
and can be easily automatized and which results in a water-
proof product. In the present method the pipe component
is enclosed in a mound whose inner surfaces are located
at a distance from the outer walls of the pipe component
and whose ends are sealed by means of an element which
is transverse with respect to the pipe component against
the pipe component, a thermoplastic material is fed into
the mound which is heated and put in motion so that -the
thermoplastic material forms a continuous layer along
the inner surfaces of the mound, the mound is removed
upon solidification of the continuous thermoplastic layer
and the space between said layer and the pipe component
is filled with an insulating material. In this way the
pipe component, for example, a pipe branch, is provided
with an insulation layer consisting of a continuous rigid
surface covering also the ends of the layer and of an
inner -foam plastic layer. The method can for the main
part be carried out in an automatic casting machine, and
as a result an insulation is obtained in which water
cannot penetrate into the foam plastic, not even during
transport of the component, and in which the foam plastic
will also not be damaged during the transport.
According to one preferred embodiment of the
method according to the invention the sealing elements
located at the ends of the mound comprise end gables
of the mound provided with a central opening for the
pipe component. Because the end gables are made integral
with the mound, the space between the mound and the pipe
component need not be sealed with any separate means.
According to a second preferred embodiment of
the invention the insulating material preferably
comprising a liquid foaming material is fed into the space
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between the solidified thermoplastic layer and the pipe
component through a hole made in the sheath surface of
the layer. Also this step can be easily automatized which
Involves additional cost savings.
I-t is oaken desirable, for example, in view of
strength requirements to make -the insulating material
adhere to the part to be insulated, in other words,
in this case to the metal pipe. This can be made possible
by cooling the pipe component during the formation of
the thermoplastic layer whereby the thermoplastic does
not adhere to the metal pipe during heating of the mound.
The cooling can be produced, for example, by feeding a
cooling medium into the pipe component.
One preferred embodiment of the method according
to the invention will be described in more detail in the
following with reference to Figures 2 to 7 of -the
accompanying drawings.
The mound 7 shown in the Figures 2 and 3 comprises
two symmetrical halves 8 and 9 which are pivotal
connected to each other by means of two hinges 10. The
mound consists of an elongated cylindrical portion for
the main pipe and a bent portion for the branch pipe
extending laterally from the first-mentioned portion
Both portions have such a configuration that their inner
surface is located at a constant distance from the outer
surfaces of the main and the branch pipes of the pipe
branch. The ends of the mound are provided with gables
11, 12 which, in the closed position of the mound,
form a continuous disc-shaped ring around the main and
branch pipe. In order to permit the pipes to extend through
the gables said gables are provided with recesses 13.
The branch pipe portion is provided with a locking means
14 for locking the mound.
The Figures 4 to 6 illustrate a pipe branch insulated
according to an embodiment of the invention and comprising
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a main pipe 15 and a transverse branch pipe 16 welded
to said main pipe. The pipe branch is surrounded by a
substantially rigid sistered layer 17 of a thermoplas-
tic material. The thermoplastic layer is provided also
with end surfaces 18 which extend from -the sheath sun-
face to the outer surface of the pipes 15, 16, see
Figure 6. The space between the outer surface of the
pipes 15, lo and the inner surface of the thermoplas-
-tic layer is filled with an insulating material 19,
preferably comprising foam plastic, which is inserted
in this closed space through a hole 20 in the thermos
plastic layer.
The pipe branch according to Figures 4 to 6 is
insulated according to the invention in the following
manner. after the branch pipe 16 has been welded to a
lateral opening in the main pipe 15, the pipe branch
is positioned in the mound according to Figures 2 and 3
in which a suitable quantity of a preferably particular
thermoplastic material is disposed. When -the mound is
closed, the pipes are exude in the mound so that they
are located along the central longitudinal axes of the
mound parts. Hereafter the mound is heated while rota-
tying it both around horizontal and vertical axes by
means of means (not shown) for such a long time that
the thermoplastic material is sistered along -the inner
surfaces of the mound. In order to prevent sistering
of the material also on the pipe surfaces the pipes are
cooled by feeding a cooling medium into them. Hereafter
the mound 7 is cooled, and the pipe branch together
with the continuous surrounding thermoplastic layer 17
can be removed from the mound. Because material is also
sistered on the inside of the gables 11, 12 of the
mound, the thermoplastic layer has end surfaces 18
which keep the pipes in position along the center lines
of the thermoplastic layer. Hereafter a hole 20 is made
in the sheath surface of the thermoplastic layer, and
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the closed space between the pipes and the thermoplas-
tic layer is filled with a liquid Roaming insulating
material 19 through the hole 20 whereaE-ter the insulate
Ed pipe branch is ready.
The insulated pipe bend shown in Figure 7 is
made in the same way but the mound must of course
have the same shape as the pipe bend.
If desired, the cooling of the pipes can be
omitted in which case the thermoplastic material is
sistered also on the outer surface of the pipes. The
gables 11, 12 of the mound can be replaced by sealing
plugs which are pressed in between the pipe and the
sheath surface of the mound.
