The present invention concerns a method for automated filling and packing powder or fluid material in long tubes. The invention also concerns a filling/packing system for performing the inventive method. This system comprises a silo for powder material or feeding tubes for fluid material, a magazine for empty tubes, and arrangements for supplying and further trans¬ porting boxes for the tubes.

Current strenuous demands regarding the work environment and safety cannot be satisfied by existing technigues for filling tubes, such as cartridges, with explosives. Besides, there is a need to develop a more efficient production and packing system for explosive charges. A high degree of automation is desired so that manual operations can be reduced to an absolute minimum.

A known method for filling powder explosive comprises injection by means of pressurized air through nozzles from the top of a tube. The explosive is thereby blown into casings placed in a magazine. To attain good packing of the explosive inside the casings, a relatively high injection pressure is required, such as 2 kg/cm ² above atmospheric pressure. After each filling, the

injection air is reduced to atmospheric pressure. This may pollute the working environment. Machinery performing this procedure is relatively expensive and requires large air consumption.

Further, Norwegian patent no. 155 613 discloses a cartridging machine for slurry explosives. It comprises a vertically standing rotary revolver magazine and pressurized container for introduc¬ ing slurry to the casings via valve controlled nozzles. Although this machine includes individual components such as a silo and a casing magazine where the individual casings can be coupled to nozzles, the machine is unsuitable and expensive with regard to filling cartridges with the powder explosive. Among other problems, compact filling of the casings cannot be achived by such a machine, which in addition lacks a sufficently effective system for feeding and withdrawal of the casings from the casing agazine.

The object of the invention was to arrive at a method and a system which in an effective manner provides an environmental and safe total production of filled long tubes, particularly charges for powder or fluid explosive.

The inventors ¹ challenge was not limited to inventing an effective filling operation, but in addition to integrate this operation with an effective feeding and withdrawal of the respective empty tubes and completely filled, closed and packed tubes.

In order to fill long tubes simply and effectively, the inventors decided to concentrate on some kind of tube magazine connectable to either a silo for powders or a feeding conduit for fluids. A non-rotary, circular magazine with a number of apertures for the tubes circu ferentially arranged along the periphery of the magazine was selected. Further, it was found to be advantageous

to have two substantially identically shaped magazines arranged so as to be pivotable on each side of an axis. During the development, it was found that feeding and withdrawal of the tube would be simpler if each of the magazines could be individually turned from horizontal to vertical position. Empty or filled tubes could then in a simple manner be conveyed into the magazine and pushed out of it. Empty tubes could be fed to the magazine by a drum on which the tubes were arranged along its periphery. The empty tubes could therefore be used as ejectors for the filled tubes in such a manner that both of the described operations coincide in time. Also, when emptying the magazine, one could use a similar drum which was shown to precisely fill the boxes with the completely filled tubes.

It was found that a fluid could be filled into the long tube by using special cannulae or nozzles having an outer diameter a little smaller than the diameter of the tubes. The cannulae or nozzles are coupled to at least one fluid feeding line or conduit. The fluid can be completely mixed when it is fed to the cannulae or nozzles. Alternatively, several fluid components may be fed via separate conduits leading into the cannulae/nozzles. The cannulae/nozzles can then be directed down into the tubes and withdrawn in step with the filling of the tubes. If desired, the filling operation can be performed by shooting the fluid against the tube's bottom plug which at the start of the filling operation is located at the tube's inlet and which is subse¬ quently pressed by the fluid into a position against or on the bottom of the tube.

When a powder is filled into the tubes, the powder is transported from a silo down into a distributor which via pneumatically controlled valves feeds the powder to the individual tubes.

When adding powder down into a tube, it may be difficult to attain a desired degree of packing of the powder. To attain this, it has been found necessary to use vibration during the filling operation. The filling and packing system must consequently include an adjustable vibrator which can operate together with the magazine and/or the tubes within the magazine.

When filling with a fluid, such as slurry or emulsion explosives, it is in the strict sense of the word unnecessary to use vibration during the filling operation. The vibrator will therefore only exceptionally be coupled in when filling with fluids.

By coupling all of these units together, one arrives at a safe and effective system for filling long tubes. The system has a capacity of at least 25 tubes/ minute. The entire operation from feeding tubes to delivery of boxes completely packed with tubes can be manned by only one person.

Special features of the inventive procedure and the system for its performance are defined in the attached patent claims.

The invention will be further explained by reference to the description of the drawings.

Fig. 1 shows how the individual units of the filling and packing system are coupled together.

Fig. 2 shows the tube magazine with the feeding arrangements for empty tubes and for powders.

Fig. 3 shows a drum for placing empty tubes into the magazine.

Fig. 4 shows a drum for withdrawal of completely filled tubes, and for feeding these to boxes.

Fig. 5 shows cannulae and nozzles for introducing fluid material into the tubes.

Fig. 6 shows a cannula for feeding and mixing two components which are fed to the tubes.

Fig. 1 shows in juxtaposition the main elements of a filling and packing system in accordance with the invention. The system starts with use of empty tubes 12 with bottom plugs 28. By using the inventive system, one ends up with completely filled or charged tubes packed in boxes 17 ready for dispatching.

The tubes 12 are conducted into the system via a container 21 and a drum 20 (see also Fig. 2) . The tubes 12 are then pushed into a loading magazine la by means of a device 16. After being filled by powder or fluid, each tube 12 is closed with a top end cover or cap 23 fed from a magazine 22 by a transporting conduit 11. The completely filled and closed tubes 12 are transferred then to a drum 18 as an empty tube 12 pushes a respective one of the filled tubes out of the loading magazines la,b. The magazines la,b are also longitudinally displaceable such that they can be positioned between magazines 20 for empty tubes and an axially displaceable magazine 18 for filled tubes. The tubes 12 are conducted out of the drum 18 and into boxes 17 which are then sealed and sent to storage.

Fig. 2 shows the charging magazines la,b in further detail. In the preferred embodiment, the magazines la,b consist of two identical parallel units la and lb which are suspended on a respective horizontal axis 2 arranged on a vertical axis 3. The

magazines la,b can be individually turned on the horizontal axis 2 and swung around axis 3 so as to thereby change places. The empty tubes 12 are conducted by means of transporter 25 from the container 21 into the drum 20 and placed along its periphery such that the location of the tubes corresponds to the apertures 8 along the periphery of the charging magazines la,b. One of the magazines la is turned around to a horizontal position, and empty tubes are pushed from drum 20 into the apertures 8. The magazine la is then turned to a vertical position and swung into a loading position under powder silo 4a or feeding tubes 4b and over vibrator 15. During filling with powder, the powder is conducted from silo 4a down over a cone 7 and outwardly to the periphery of distributor 5 with pneumatically controlled nozzles 6 and down into the tubes 12. Vertically displaceable pins 26 bring the nozzles 6 into operation with the tubes 12, such that the nozzles 6 may penetrate into at least part of each tube 12. The tubes 12 are vibrated during filling. This can be done in several ways. For example, a continually operating vibrator 15 can be brought into engagement with the tubes 12 during filling operations by means of the pins 26 arranged on a plate 27 coupled to the vibrator 15.

After finishing filling, the magazine is swung over to the right position (at lb) shown in Fig. 2. There, the tubes 12 are sealed with covers or caps 23 fed via conduit 11 to the sealing apparatus 9 with holes 10 placed right over the respective apertures 8 in the magazine la. The magazine la is turned to its horizontal position after the tubes 12 are sealed with the covers 23. In this position, the filled tubes are pushed out of the magazine la as it is simultaneously reloaded with empty tubes 12 from the drum 20.

Fig. 3 shows the drum 20 with magazine 21 for empty tubes placed at a distance from each other corresponding to that of the apertures in loading magazines la,b.

Fig. 4 shows the drum 18 with magazine 19 for putting covers 23 onto filled tubes 12. These tubes 12 exit from magazine 19 through canals 24 and go down into boxes 17.

Fig. 5 shows three fundamentally similar methods for adding a completely mixed fluid to the tubes 12. In Fig. 5a,b,c is shown a tube 12, which can be a tube to be loaded with fluid explosive. The fluid 32 is added from feeding conduit 4b (not shown) . As shown in Fig. 5a, the fluid 32 is pressed through cannula 36 and out through its opening 30 down into the tube 12 with its bottom plug 28. The cannula 36 has a slightly smaller diameter than the tube 12 and is directed downwardly inside the tube before filling commences. The tube 12 is then filled from the bottom and upwardly.

In the method illustrated in Fig. 5b, the tube 12 is filled from its upper open end where the bottom plug is positioned at the start of the filling operation. The tube 12 is in this embodiment equipped with end flanges 29 upon which the bottom plug 28 will lay against when the tube 12 is filled. Filling is done as the fluid 32 presses the plug 28 downwardly against the bottom of the tube 12 simultaneously as the cannula 36 is conducted correspond¬ ingly downwardly within the tube 12. Cannula 36 is withdrawn when the tube is completely filled.

In Fig. 5c, the fluid is added at relatively high pressure through a nozzle 36 with a nozzle opening 31. The tube 12 is filled from the bottom, and the nozzle 36 is drawn out in step with the filling of the tube 12.

The present invention has provided a safe and efficient method and apparatus for producing filled tubes as well as charges with powder or fluid materials. The actual filling of all the tubes in a magazine takes about 45 seconds and the total cycle time is

about 1 minute. The present invention provides a relatively simple and operationally secure system which can be manned by just one operator. The system is very flexible in that it can easily be switched from filling powder to fluid material.