Apparatus for the release of the jacket material of rod-shaped carriers and recovery of the same, particularly of waste welding rods

The jacket material of welding rods is removed and processed for reuse, and the rods are cleaned and processed for reuse by delivering the jacketed rods to a ball mill, grinding the jackets from the rods within the ball mill by oscillating the jacketed rods in the environment of equally long cylindrical grinding bodies while holding the rods and the grinding bodies against axial movement and in generally parallel disposition with respect to one another. The detached jacket material is conveyed continuously from the grinding chamber and further comminuted, the transport of the ground material being supported by flowing a fluid through the grinding chamber. The fluid may be a gas or a liquid and may contain a chemical reacting agent for an after treatment. The fluid may advantageously be circulated, freed from the solid material transported thereby, regenerated and/or heated. Both neutral and chemically reacting fluids may be alternately employed, depending on the particular materials involved.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a apparatus for the release of the jacket 
material of rod-shaped carriers and for the recovery of the material, and 
the carriers for reuse, and more particularly to the removal of jacket 
material of waste welding electrodes in which the jacketed rod-shaped 
carriers are delivered chargewise to a ball mill and the unsheathed rods 
are taken chargewise from the mill, while the released jacket material is 
conveyed from the grinding chamber and, if necessary, further comminuted. 
2. Description of the Prior Art 
Heretofore it has been attempted to recover the jacket material of waste 
welding rods in squeezing or striking comminution machines. This 
technique, however, has the disadvantage that the rod-shaped carriers 
become bent or shattered and must be scrapped. As with automatically 
controlled production lines for welding rods, always greater quantities of 
reject electrodes occur, the most complete and economical recovery of the 
jacket material and the carriers becomes more important, along with the 
preparation of the jacket materials. 
In U.S. patent application Ser. No. 712,942, filed Aug. 9, 1976, issued 
Apr. 25, 1978 as U.S. Pat. No. 4,085,898, and assigned to the same 
assignee as the present invention, the removal of the jacket material by a 
new and unique technique is disclosed in which the welding electrodes are 
placed in grinding chambers of substantially equal length to the 
electrodes, the grinding chamber being filled to about 40% of its volume 
with grinding rods. The chamber is perforate to permit the broken jacket 
material to fall therethrough for removal through a discharge conduit as 
the chamber is oscillated. 
SUMMARY OF THE INVENTION 
The primary object of the present invention is to improve the removal of 
jacket material, in particular welding rod jacket material, over the 
method and apparatus set forth in the above-identified application so as 
to provide a more economical recovery of the rods along with the 
simultaneous comminution of the jacket material. 
According to the invention, the above object is achieved in that a fluid is 
conveyed through the grinding chamber to support the transport and 
discharge of the released jacket material, and that the unsheathed rods, 
before a charge wise removal, are post-treated in the grinding chamber. 
Upon the grinding operation in the ball mill, cylindrical grinding bodies 
effectively impact the jacket material to release the same without 
damaging the carrier rods. The jacket material is continuously ground off 
and advantageously accelerated by the fluid and conveyed off more rapidly 
than would occur through discharge by gravity from the grinding chamber. 
As a result, several steps of the method may be carried out more rapidly, 
supported by vibration of the mill: namely, the removal of the dust of the 
unsheathed rods or the moist detachment of sheathing residues; the 
neutralization after chemical detachment; and the drying after a wet 
treatment in the grinding container, without the rods having to be 
transported or rearranged, and before the rods are removed, chargewise, 
for reuse directly or conveyed to a storage container ready for reuse. 
According to a further feature of the invention, the flowing fluid may be 
a gas. This is particularly of advantage when the rods, dry and blown free 
from dust, may be conveyed to a new use because the dust removal is 
effected concurrently with the jacket removal operation by the gaseous 
transporting medium. 
It is further provided that the fluid be a liquid, with the advantage that 
the transporting medium is able to enhance, in addition to the accelerated 
discharge of the jacket material, also the release or disintegration 
thereof and, with relatively hard sheathings, their detachment. In 
addition to the discharge of the detached jacket material, without change 
of media, a time saving washing operation is performed on the rods. 
If it is further provided that a chemically reacting agent suitable for the 
after-treatment is utilized as the flowing fluid, the detachment of 
residues of the jacket material and adhesions thereof may be obtained. In 
this case, and quite advantageously, according to the composition of the 
jacket material, a base or acidic liquid, or the injection of a chemically 
active mist, into the flowing fluid, contributes to the detachment or 
release of the jacket material and/or accelerating the detachment. 
According to a further feature of the invention, it is provided that a 
neutral medium be utilized alternately with a chemically reacting medium. 
This is of particular advantage when, after a liquid reaction phase, a 
neutralization and a drying of the cleansed or purified rod surface is 
necessary. 
According to another feature of the invention, it is provided that the 
flowing medium be circulated and be freed from the solids carried thereby, 
and that the medium, if necessary be regenerated and/or heated, whereby 
the detached jacket material is continuously removed from the transporting 
medium in a solid separator, for example, by means of a cyclone or similar 
apparatus, and conveyed to the comminution state which is connected in 
series with the separator. Thereby, it is of advantage that the quantity 
of transporting medium present in the process remain small and need only 
be brought back to a degree of purity occasioned by the particular method, 
whereby an emission, for example of portions of dust in the environment or 
in the liquid transporting medium, may be prevented at little expense. 
An apparatus adapted for carrying out the method comprises a ball mill 
which includes a grinding tube having at least one exchangeable grinding 
container, with the advantage that several grinding containers may be 
provided as rapidly exchangeable inserts which are adapted to the 
particular lengths of the carrier rods as charging containers, and through 
the exchangeability of the grinding containers contribute to the 
acceleration of the charging operation. In addition, the grinding 
containers may be exchanged according to the course of treatment provided. 
Thereby, it is of advantage that the exchangeable grinding container is 
constructed as a grate or grid and is centered with a wedge-ring tension 
element, in that additional locating and fitting operations are 
unnecessary upon the introduction of a new grinding container. An 
adaptation of the grinding containers to the length of the carrier rods to 
be processed is possible in that the grinding container is closed with 
rapid-closure covers having attachments which project different distances 
into the container in order to permit no axial shifting and crossing of 
the rods, and to thus prevent damage to the rods during the grinding 
operation. 
According to another feature of the invention, the grinding tubes or pipes 
of the apparatus are equipped with several conduits which are uniformly 
distributed in the lower area of the grinding pipe sleeve over the length 
of the sleeve for conveying off the flowing fluid and, of course, the 
broken jacket material being transported by the fluid. Through this 
distribution of the discharge conduits, a continuous withdrawal of the 
broken pieces of jacket material may take place with a gaseous 
transporting medium, as well as with a liquid transporting medium and the 
broken pieces are accelerated along the shortest path toward a separator 
and a subsequent comminution stage. Thereby, advantageously the grinding 
operation is intensified and completed in a shorter time, and in addition 
the efficiency of a washing operation, rinsing operation or drying 
operation is improved by the zone wise passage of the particular medium.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, a ball mill is illustrated as comprising a grinding 
pipe 1 having located therein a grinding container 3 which is spaced from 
the pipe 1 by means of an annular chamber 2. The grinding container 3 may 
be constructed of a mesh grating so as to be perforate and have openings 
therein for the passage of the ground jacket material. The grinding 
container 3 contains jacketed rods 4 which are constituted, for example, 
by waste welding electrodes, and equally long cylindrical grinding bodies 
5, which under the influence of the impulses introduced by an oscillatory 
drive (not shown) causes the detachment of the jacket material from the 
carriers rods. It is desirable that not only the jacket material be 
recovered for recycling, but also the relatively long carrier rods are to 
be recovered without damage, that is, unsheathed, straight and without 
squeezing. The chargewise delivery (in the grinding containers) of the 
waste welding electrodes into the grinding container is symbolically 
illustrated by the arrow 6, while the chargewise removal of the unsheathed 
rods (initially still in the grinding container) is symbolically 
illustrated by the arrow 7, the rods being delivered either directly back 
for receiving a new jacket or stored in a container ready for receiving a 
new jacket. 
The ground pieces of jacket material are continuously discharged from the 
annular chamber 2 through discharge pipes 8 which are distributed along 
the lower side of the grinding pipe 1 and are further comminuted in a 
grinding stage 17 to the fineness required for the preparation of a new 
sheathing, and then conveyed to the material preparation stage (not 
shown). 
In order to accelerate the discharge of the broken pieces of jacket 
material, either a liquid or gas transport medium is provided, with whose 
aid the ground particles are appreciable accelerated, whereby the grinding 
operation is intensified and shortened. With tests related to the 
shortening of the grinding operation, with a suitable filling of waste 
electrodes, in one particular case, the grinding duration could be reduced 
from a gravity operation of 15 minutes to less than 5 minutes by utilizing 
the present invention with a forced discharge. Accordingly, the grinding 
operation was reduced to less than one-third. 
The carrier rods must, however, be freed of tightly adhering jacket 
residue, or also from a dust coating, and in order to attain a chemically 
pure surface, the rods are subsequently treated in a suitable manner, that 
is, washed and dried. For this purpose, the washing operation is 
advantageously to be carried out with agents determined as to the chemical 
composition of the jacket material and suitable for the rod surface so 
that the entire, necessary after-treatment is completed in the ball mill, 
without an intermediate transport of material being necessary. In this 
connection, appreciable costs related to work time of operating personnel 
are saved and there is a saving in transportation time over techniques 
heretofore used, by means of which the regeneration of the rods may be 
carried out economically, although the introduction and removal of the 
rods must be carried out in charges. An apparatus for carrying out the 
detachment process is provided for this purpose with several discharge 
conduits 8 which are uniformly distributed on the lower side of the 
grinding pipe 1, with which a gas conduit 14 and a liquid conduit 22 may 
be selectively connected. Inasmuch as one skilled in the art would readily 
appreciate the interconnection of several of the conduits 8 with the 
conduits 14 and 22 by means of additional sections of conduit and by means 
of the illustrated valves, or suitable equivalence thereof, the same will 
not be further discussed herein. This also applies to the other valves 
illustrated in the upper portion of the drawing, whose operation will be 
readily apparent to those skilled in the art. 
A gas circulation system is diagrammatically illustrated on the right-hand 
side of the drawing, and a liquid circulation system is illustrated on the 
left-hand side of the drawing. 
A stream of gas is fed to an input conduit 9' of the ball mill grinding 
pipe 1 by means of a blower 10 and a conduit 11, or a stream of liquid is 
fed to the conduit 9' by means of a pump 12 through a conduit 13. 
Suitably, the gaseous medium is freed from the discharge portions of 
solids and supplied anew to the grinding container 3. For this purpose, a 
cyclone separator 15 is provided in the conduit 14 as a solids separator, 
the solid material being discharged from the cyclone separator 15 through 
a gas-tight feed device 16 for the continuous discharge of solids to the 
subsequent comminution stage 17 which is connected in series with the 
separator 15. The gas-tight feed device 16 may be, for example, a worm 
conveyor. In each of the circulating systems a respective heat exchanger 
18, 18' may be provided to heat the flowing medium. Thus, for example, for 
the drying of the rods after a washing operation or for the acceleration 
of a chemical reaction, and indeed when the grinding operation is to be 
shortened by means of the addition of rapidly reacting agents, or when 
such agents are required for a surface treatment, the heat exchangers 18 
may be energized. The pump 12 feeds a liquid, for example, water, through 
the conduit 13 and the conduit 9' into the grinding pipe 1. With the aid 
of this liquid, the ground jacket pieces are conveyed off at 9 from the 
discharge conduits 8 to the conduit 22. The broken pieces of jacket 
material are then deposited in a solids separator 20 and, by way of a 
conveyor device 21, are continuously forwarded through a conduit 
(illustrated by a broken line) to the comminution stage 17 for the fine 
grinding operation. Again, the conveyor 21 may be a worm conveyor. The 
rinsing liquid or washing liquid is drawn off by the pump 12 from a 
storage container 24, or through the conduit 23' in the clarified portion 
of the solids separator 20. In this connection, it is of advantage that 
the quantity of liquid found in circulation, after the solids separation, 
may be inserted again upon the removal of sludge. In this manner, the use 
of a liquid medium is limited, which is particularly favorable when an 
expensive agent must be utilized. The utilization of a chemically reacting 
medium as the transporting means, provided in any case upon the 
after-treatment, is of advantage when its chemical properties support the 
grinding operation, whereby the additional investment for separate 
conveying apparatus and switching apparatus required for the transfer 
switching operation upon change from transporting medium to an 
after-treatment medium, may be saved, by means of equalization of the 
after-treatment medium as the transporting medium. 
The carrier rods to be prepared for reuse, particularly the welding 
electrodes which have been separated out as waste, occur in different 
lengths. In one case, standard rod lengths necessary for recycling are, 
for example, 450, 550, 650, 700, 800, 900, 1050 mm. The grinding of the 
jackets of the carriers rods takes place by means of the elongate grinding 
rods 5 which are of the same length as the carrier rods which are to be 
unsheathed. As long as the carrier rods and the grinding rods cannot be 
deflected in the axial direction they roll against one another whereby the 
jacket material is quickly separated due to the oscillatory impulses. Upon 
shifting of the rods in the axial direction, in the case of detachment on 
one side of the jacket, crossing and interconnecting may easily occur, 
whereby the carrier rods of the welding electrodes become bent or 
deflected. Such rods are then no longer suitable for receiving a new 
jacket. It is therefore necessary that the grinding container be adaptable 
to the different lengths of the carrier rods to be processed. 
Advantageously, in order to reduce the number of the grinding containers 
to be held ready, and in order to be able to equalize intermediate 
dimensions, according to a particular feature of the invention the 
grinding container is closed with rapid-closure covers, each having a 
different length attachment which projects into the grinding part, 
occasioned by means of the grinding pipe and its final tolerance. Each 
attachment to the cover is, according to the invention, of a diameter 
adapted to tightly close to the internal diameter of the grinding 
container in order to prevent a locking of the rods. Through the longer 
attachment fixed to the cover, the grinding chamber is so shortened in 
axial length, that the rods retain only a small permissible axial play in 
order not to be able to cross or interconnect. In the aforementioned group 
of standard lengths, with three differently long cover attachments and two 
grinding container lengths, the grinding containers are inserted for eight 
different lengths of electrodes. 
The grinding pipe 1 is equipped with several attachment conduits 8 for the 
attachment of the discharge pipe conduits 9, the conduits 8 being 
connected centrally of each section of the grinding pipe and therefore 
distributed in the lower area of the grinding pipe sleeve uniformly in the 
axial direction. Through this distribution of the discharge conduits, the 
detached jacket material may be removed along the shortest path and with 
the greatest speed, without the individual broken pieces of jacket having 
to be moved along mutually retarding on long chutes to the ends of the 
pipe. At the same time, and quite advantageously, additionally the wear on 
the apparatus is appreciably reduced, and therewith the life of the 
grinding pipe is extended. According to a further feature of the 
invention, the exchangeable grinding container 3 is constructed as a grate 
or as a cylindrical sieve and is centered with a wedge-ring tension 
element, whereby the surface of the grinding container 3 which is 
subjected to wear may advantageously be turned in order to prevent wear on 
one side. With the aid of a wedge-ring tension element, the centering of 
the grinding container is made possible rapidly and accurately, and the 
grinding container exchange may be carried out in a shorter time. 
A more detailed description will now be given with respect to the ball mill 
and the rapid closure structure. 
FIG. 2 illustrates a ball mill which is known per se, comprising two 
parallel grinding tubes 1 and 17, which are fixedly connected by clamping 
yokes 25 to a carrier frame. The carrier frame comprises two legs 26 and a 
connecting tube 27. On the sides of the legs 26 are brackets 28 through 
which, and via rubber springs 29, the unit comprising the grinding tubes 
and carrier frame is supported for oscillation of a stand 30. 
In the interior of the legs 26 are located imbalance masses, which are 
connected to a coupling shaft by the connecting tube 27. The drive of this 
oscillating arrangement takes place by means of a motor (not illustrated 
on the drawing), through a drive shaft 31. The grinding tube 1 contains a 
number of grinding containers 3 which are arranged spaced from the 
grinding tube wall within the tube 1 so that an annular chamber 2 results 
between the inner wall of the grinding tube 1 and the outer wall of the 
grinding container 3. This annular chamber 2, by way of three material 
outlet pipes 8, is connected with a collection conduit 9 which serves for 
conveying off the released jacket material. The collection conduit 9 
passes into the conduits 22 (FIG. 1) or 14 (FIG. 1), each according to 
whether the jacket material is conveyed by a liquid medium or a gaseous 
medium. The jacket material separated from the carrier medium passes 
through the conduit 32 for further comminution. In this manner, the 
fineness of the jacket material is attained for a subsequent preparation. 
The jacket material comminuted to the final degree of fineness is 
discharged from the grinding tube 17 by means of an outlet conduit 33. 
In order to charge the ball mill, a grinding container 3 is filled with 
rod-shaped grinding bodies 5 (FIG. 1) and the rod-shaped carriers 4 (FIG. 
1) which are to be unsheathed, and the grinding container is placed into 
the grinding tube 1. During the operation of the ball mill, a loosening of 
the jacket material takes place and the material, through the chamber 2 
and supported by the flowing carrier medium, is continually discharged. 
After conclusion of the unsheathing process, the grinding containers 3 are 
removed from the grinding tube 1, so that the rod-shaped carriers may be 
removed from the grinding containers. 
An end area of a grinding tube 1 with a grinding container 3 is illustrated 
in an enlarged view in FIG. 3. A free chamber 2 separates the inner side 
of the grinding tube 1 from the outer side of the grinding container 3, 
which supported on its end facing the end area of the grinding tube 1 on a 
ring 34. The ring 34 is advantageously welded to the grinding container 3. 
Such a support is provided at both ends of the grinding container 3 when 
its length corresponds to that of the grinding tube 1. In other cases, the 
support must be carried out in the interior of the grinding tube 1 on 
spacing members and supporting shoes, so that in the free chamber 2, the 
released jacket material is free to move from the carriers to the grinding 
tube 1. 
The grinding container 3 has a rapid closure cover 35 which fits with its 
outer contours in that portion of the grinding tube 1 which is conically 
shaped on its inner side in a small area 36. The cover 35 is provided with 
a handle 37 for easier removal from the grinding container 1 and for 
arresting in the grinding container several slide members 38 which are in 
engagement with a corresponding recess 39 of the grinding tube 1. 
In order to be able to easily adapt the axial length of the inner chamber 
of the grinding container 1 to the different dimensions of the rod-shaped 
carrier to be unsheathed, particularly in order to be able to equalize 
intermediary dimensions of the carrier, the grinding container 3 is 
equipped on one or both sides with rapid closure covers 35, which are 
provided with exchangeable attachments 40 of the same or different length 
projecting into the grinding container 3. 
Each attachment 40 on the cover 35 is, according to the invention, adapted 
in diameter so as to connect closely with the diameter of the grinding 
container rim. Through the attachment 40 fixed on the cover, the grinding 
container is advantageously shortened in axial length so that the rods may 
only have a small axial play. In the case that each grinding container 3 
is closed on one end with a rapid closure cover 35, for which three cover 
attachments 40 of different length are available, (and the grinding 
container can be used without the cover attachment 40, with only two 
different grinding container lengths, eight different lengths of electrode 
may be treated, because of the possibilities of combination between 
grinding container length and the three different thicknesses of the 
attachment 40. 
The grinding container 3 is centered in the grinding tube 1 by means of a 
keyway ring clamping element 41 which is known per se. The element 41 is 
located, in each case, in the end area of the grinding tube 1 and 
comprises a ring element 42 and a plurality of screws 43, with which the 
ring element 42 is fastened to the grinding tube 1. The grinding tube has 
a widened portion 44 whose inner side, that is in the direction toward the 
end of the grinding tube 1, is conically widened in an area 45. The 
conicity of the grinding tube 1 corresponds to a conicity of the outer 
contour of the ring element 42. By tightening the screw 43 a sliding of 
the corresponding conical surfaces on one another results, and in this 
manner radial pressure forces exerted on the ring 34, as well as a center, 
and also an axial fixation of the grinding container 3 occurs in the 
grinding tube 1. Advantageously, the possibility of turning the surface of 
the grinding container 3 which is subjected to wear is made possible, in 
order to prevent wear of the container on one side. With the aid of the 
keyway ring clamping element 41, the centering of the grinding container 3 
and an exchange of the grinding containers may be carried out rapidly and 
accurately. 
Although we have described our invention by reference to specific 
illustrative embodiments thereof, many changes and modifications of the 
invention may become apparent to those skilled in the art without 
departing from the spirit and scope of the invention. We therefore intend 
to include within the patent warranted hereon all such changes and 
modifications as may reasonably and properly be included within the scope 
of our contribution to the art.