Improvements in the Method and Means of Drying the Insulation of Electric Cables, Armatures, Bobbins, and the like.
Year: 1898

page_text: Date of Application, 9th Aug. 1898
Complete Specification Left, 8th May, 1899-Accepted, 9th Aug., 1899
Improvements in the Method and Means of Drying the Insulation of
Electric Cables, Armatures, Bobbins, and the like.
I, EMIL PASSBURG, of 33, Brückenalle, Berlin, in the Empire of Germany,
Manufacturer, do hereby declare the nature of this invention to be as follows:-
The drying of electric cables suffered till now from the fault that the necessary
degree of dryness of the cables could not be recognized or gauged with surety
at the end of the drying process. By the means hitherto known it was necessary
in order to prove the conductibility of the cable, after taking it out of the drying
apparatus, to pass an electric current through it, the conductibility of the cable
depends upon its absolute dryness, for this purpose the manufacture of cables
was hitherto continued until after the lead covering had been fitted, they were
then twisted and if found of faulty conductibility in consequence of dampness
therein it was necessary to remove the expensive lead covering and to again
go through the drying process at the expense of both time and money.
A further fault in the drying apparatus hitherto used was that they were
only able to contain one coil of cable which was let down from the top into the
apparatus by means of pulley blocks or the like. This drying apparatus not
being high but having a large diameter took up considerable space in the factory.
Moreover the apparatus was not very effectual since the covers being movable
on the top the apparatus could only be heated from beneath and consequently
the heat in the apparatus only reached one side of the cable coil so that the
latter was dried at its lower side while it was still damp at its upper side which
necessitated that the drying process should be continued for a considerable
length of time also one could not ascertain if all the parts of the cable were
sufficiently dry.
In order to avoid these faults I have constructed a vacuum drying apparatus
in which the coils of cable are introduced upon movable trays arranged story
like one above another, between hollow heating plates or planes of coiled or bent
heating pipes in order that the cables are exposed on all sides equally from
above and below to the heat rays causing thus a quicker and more thorough
drying of the cable and an easier manipulation of the apparatus than was hitherto
possible.
Further a condensing apparatus is arranged to condense the vapors coming
out of the cable, and collects the same in a measured manner in order that the
dryness of the cable can be ascertained from an estimation of the amount of
moisture collected. The drying is effected as follows-
By opening a valve steam is introduced through a steam distributing pipe
into the heating plates or tubes and goes back again through another pipe.
The door of the apparatus is opened and the travs which are provided with
wheels or runners or the like and charged with cable coils are brought before
the story like heating system of the apparatus by means of an hydraulic or

page_text: electric lift or in any other manner, they are then rolled on rails arranged suit-
ably in the apparatus and are hermetically closed therein by means of the door.
Then a vacuum is made in the condenser and in the apparatus by opening an
air pump valve.
;
The heating installation of the apparatus radiate their warmth from both
sides upon the cable whereby by influence of the vacuum the moisture quickly
evaporates. Cooling water is led into the condenser and in its passage through the
same comes against the cooling tubes of the condensor thus condensing the vapors
coming from the cables into the tubes and the moisture is then collected in re-
ceivers arranged under the condensor. The receivers have receiving glasses through
which the dropping of the condensed vapors can be observed. The condensed
water flows from the upper receiver into a lower receiver through a tube out of
which at the commencement of the drying process the liquid streams in a jet.
Towards the end of the drying process, the evaporization being weaker the liquid
· only drops out of the same. The formation of drops becomes less the more the
drying process is advanced, then the liquid is allowed to flow out of the receivers
by opening a cock in the lower receiver. After having closed the lower receiver
cock and the vacuum being again made by the suitable position of the circula-
tion cock and after having opened a second circulation cock the remaining
moisture is evaporated out of the cable and the condensed water flows out of the
lower receiver into a glass tube suitably arranged and which can be provided
with a scale.
This installation permits the measurement of the liquid in the glass tube so
that when after a certain time the level of liquid in the tube does not rise
higher it is certain that the evaporization is finished and that the cable is dry.
Instead of the described plates or tubes heated with steam electrical heating
bodies or other heating means can be employed. Also the drying apparatus
can be of any suitable shape such as round cylindrical or square.
The apparatus is applicable in the same way for the drying of bobbins wound
armatures and the like.
Dated this 9th day of August 1808
HERBERT HADDAN & Co.,
Agents to Applicant,
Improvements in the Method and Means of Drying the Insulation of
Electric Cables Armatures, Bobbins, and the like.
I, EMIL PASSBURG, of 33, Brückenalle, Berlin, in the Empire of Germany,
Manufacturer, do hereby declare the nature of this invention and in what man-
ner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
The drying of electric cables and covered wires has hitherto been unsatis-
factory owing to the long duration of the drying methods used, the high tem-
perature required and the circumstance that the degree of dryness of the cable
or wire could not be recognised with surety at the end of the drying process.
By the hitherto known process it was necessary for examining the cable as to
its efficiency, which depends upon its absolute dryness, to pass an electric current
through it after it had been taken out of the drying apparatus. For this purpose
the manufacture of the cable was continued so far as to provide it with its lead
clothing. If it were then found on examination that its conductivity was too
little or the insulation faulty in consequence of dampness remaining therein, it

page_text: was necessary to remove the expensive lead covering and dry the cable again
with a very considerable loss of time, material, and labor.
A further disadvantage of the drying apparatus was that they were only able
to contain one coil of cable which was let down from the top into the apparatus
by means of pulley blocks or the like. These drying apparatus not being high
but having a large diameter took up a considerable space in the factory. More-
over the capacity of these apparatus was not adequate to their considerable space
since the covers being movable on the top, the apparatus could only be heated
from beneath and consequently the heat in the apparatus reached only one side
of the cable coil, so that the latter was sometimes dry at its lower side while it
was still damp at its upper side, which necessitated that the drying process
should be continued for a considerable length of time. This often resulted in
an overheating of the first dried side and the carbonization of the same, that is
to say the destruction of the insulating material, whilst as mentioned already
it could not be ascertained if any parts of the cable were even sufficiently dry.
In order to avoid these faults of the hitherto existing apparatus I have con-
structed a drying apparatus as illustrated in the accompanying drawings in
which Fig. 1 is a vertical section thereof, Fig. 2 a horizontal section on the
line 22 of Fig. 1 and Fig. 3 a similar section showing tubular heaters.
In this apparatus:-
-
1. The coils of cable or covered wire or bobbins of the same provided with
armatures such as induction coils are introduced upon movable trays arranged
story like one above another and between steam tight heaters h h or bent heating
pipes S S so that the cables or wires are exposed equally from above and
below to the heat, causing quicker and more thorough drying and an easier
manipulation of the apparatus than was hitherto possible.
2. A condensing apparatus C is arranged to condense the vapours coming out
of the cable, to collect and measure the same, in order that the degree of dryness
of the cable can be ascertained from their quantity.
The drying is effected in the following manner.
By opening a valve v steam is introduced through a steam distributing pipe D
into the heating plates h or bent heating pipes S of the apparatus and goes out
again through the pipe D¹. The door T of the drying chamber is opened and
the trays W, placed on trucks W', which are provided with wheels or runners W2
and charged with the cable coils K, are lifted before the story like heating
system by means of any suitable lift and are then rolled on rails f f arranged
suitably in the chamber, and then hermetically closed therein by means of the
door T.
Then a vacuum is made in the chamber by opening a valve in the suction
pipe of the air pipe, whilst the heating plates or the bent heating pipes S in
the apparatus radiate their heat from both sides upon the cable whereby the
moisture quickly evaporates.
Cooling water is led into the condenser at i and flowing out at in its passage
through the same, comes against the cooling pipes, thus condensing inside the
pipes the vapours coming from the cables and the moisture is then collected in
receivers E El arranged under the condenser. The receivers E E¹ have win-
dows gg through which the dropping of the condensed vapours can be observed.
The liquid flows from the upper receiver E into a lower receiver E' through
a dropping tube or out of which at the commencement of the drying process
the condensed liquid falls in or like a stream. But towards the end of the
drying process, the evaporation being less, the liquid only drips out of pipe o r.
The formation of drops becomes less the more the drying process advances,
whereupon the liquid collected in the receiver E¹ can be allowed to flow away
by opening a cock m. After having closed this cock m and having again pro-
duced the vacuum by means of the cock B, the remaining moisture of the cables
is evaporated so that the condensed liquid now produced slowly, passes through

page_text: the pipe or into E¹, whereupon on opening the cock ? the liquid falls into the
glass tube t suitably arranged and provided with a graduated indicating scale.
This installation permits the measurement of the liquid dropped into the
glass tube so that when after a certain time the level of the liquid in the glass
tube t does not rise higher it is certain that the vaporization has ceased and that
the cable is dry. It is then immediately taken out of the apparatus and there
is no fear of insufficient conductibility in consequence of any dampness still
remaining therein.
Instead of the heaters h h or bent pipes S S heated by steam there can natu-
rally be used also electrical heating bodies or any other heating means, heating
the cables from two sides, that is from above and below; also the form of the
drying apparatus may be cylindrical or square.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what
I claim is:
In apparatus for drying the insulation of electric cables, armatures, spools
and the like.
1. The herein described vacuum drying apparatus A of box like or cylindrical
form with the steam chambers or steam tubes s s or electrical heaters or
other heaters arranged in stories between which heating systems the cable or
wound wire to be dried may be inserted in trucks so that the heat warms the
cable or wire on both sides.
2. The herein described condenser C for receiving and measuring the liquid
evaporated in vessel A, having the collecting chambers E E' with windows g',
drop tube o and glass tube or receiver t, for the purpose of ascertaining or show-
ing the progress and completion of the drying process substantially as described.
3. The combination of the apparatus described in Claims 1 and 2 with a
vacuum pump or other suction device for producing a vacuum.
Dated this 8th day of May 1899.
HERBERT HADDAN & Co.,
Agents to Applicant,
18, Buckingham Street, Strand.