Improvements in the Manufacture of Enamelled Pipes and Tubes.
Year: 1899

page_text: Date of Application, 23rd Jan., 1899-Accepted, 19th Aug., 1899
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Enamelled Pipes and Tubes.
I, EMIL FERDINAND GUSTAV PEIN, of 33, Kaiser Wilhelmstrasse, Hamburg,
in the Empire of Germany, 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:-
This invention relates to a method of and device for coating the inner and
outer walls of pipes and tubes with liquid enamel, which will resist moisture,
chemical influences of all kinds and heat, and in addition form an insulator for
electrical currents.
The main object of the invention is to enable the inner walls of narrow tubes
to be coated with enamel, the tube so treated being adapted for purposes of all
kinds, such for example as for liquids in chemical manufactories, beer pipes and
the like, and in addition to this as insulating pipes for the laying of electrical
conductors.
As regards the tubes to which this process is to be applied, the only point to
be considered is that the material of which they are formed should be adapted to
receive readily, and retain the enamel with which it is desired to coat them.
In no other respect does the kind of tube employed exercise any influence upon
the enamelling operation.
It must however be taken into consideration that pipes for the principal
purpose above named, that is to say for constituting insulators for electrical
conductors, have a certain length which is most suitable for the purpose in view.
The most suitable length for such tubes may be taken as three metres.
In the employment of pipes of such a length and of comparatively very small
cross section, considerable difficulty is experienced, owing to the fact that a
special device must be employed for drying the interior of the pipes.
Such a device is illustrated in the accompanying drawing, in which;
Figure 1 is a longitudinal section of the improved apparatus and
Figure 2 is a cross-section partly broken away.
After the pipes have been coated internally and externally with enamel, which
may be effected either by immersing them in the liquid mass of enamel so that it
adheres to the walls, or by causing the enamel to flow through the pipes by
means of suitable devices, the drying process is effected.
When the pipes have been coated with the enamel, the next step is to dry the
enamel in such a manner that when the drying operation is completed the enamel
may lie uniformly upon the entire surface of the pipe.
The natural tendency of the liquid enamel is to collect upon the lowest points
of the pipes. For this reason the inside middle point of a pipe three metres
long is more difficult to dry than the extremities to which the air has freer access.
The object of the special device above referred to is to overcome this difficulty.
Upon an axis a, which is caused to rotate by means of toothed wheel gearing b,
and adjacent to each extremity of such axis is arranged within a drum c which
forms a casing for the whole of the apparatus, discs d and e respectively. These

page_text: discs are provided with conical sockets f arranged exactly opposite one another,
for the reception of the pipes to be dried.
These pipes are inserted in the sockets f of the left hand disc d through the
trap or door 9 and clamped in the spring holders which are provided upon a
supporting disc i arranged upon the shaft a. This disc serves to prevent the
pipes from sagging.
The disc e is capable of displacement along the shaft a, and when the ends of
the pines have been inserted in the sockets f upon the disc d and the disc e fixed
in position, the door g is closed. At one end of the drum c is provided an exhaust
pipe j, through which is exerted the suction of a flue or of a powerful ventilator k.
This suction device draws atmospheric air, which may be previously dried and
heated, and which enters the drum by way of the inlet pipe 7, through the pipes
to be dried, whereby a uniform and rapid drying of the enamel is effected. The
discs and c do not fit tightly against the walls of the enclosing drum, so that
a portion of the air passes through the aperture m and passes over the outer walls
of the pipes, thus drying them at the same time.
As the enamel is of a pasty consistency, it has a tendency to collect in the
lowest portions of the pipes, and unless special measures were taken to prevent
this, these latter would not be enamelled uniformly and would be useless for
practical purposes.
The pipes are however caused to rotate together with the discs d and e between
which they are placed, whilst the air is passing through them, owing to the
rotation imparted to the shaft a by means of the gearing b. By this means all
parts of the pipes successively assume the lowest position, so that no time
is allowed for the liquid enamel to collect at any one point; it is therefore
uniformly distributed.
When the drying operation has been completed, stoving is effected in the usual
manner.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
The hereindescribed improvements in the manufacture of enamelled pipes and
tubes, characterised by the fact that after the pipes, which may be manu-
factured in any suitable manner and of any appropriate material, have been
coated in any desired manner with the wet mass of enamel, they are
placed within a closed drum upon a vertically rotatable flame and dried
by means of currents of air which are conducted through and over them, the
pipes rotating around the horizontal driving shaft during this time, in order
that the enamel may be uniformly distributed upon the walls of the said pipes
and so be in readiness for the stoving operation which is subsequently effected.
Dated this 23rd day of January 1899.
HASELTINE, LAKE & CO.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.