A METHOD AND A SYSTEM FOR PRODUCING BLOCK BODIES FROM LOOSE MATERIAL SUCH AS SPHAGNUM

Abstract: In the production of growth blocks of sphagnum there are considerable operational problems with the required compacting of the loose sphagnum, as both compaction worms and pistons may easily get stuck. Instead, the invention provides for the use of a suction technique, whereby the loose sphagnum (2) is sucked into a perforated pipe (34) in a suction chamber (28), whereby a marked compaction of the material is achievable without any use of mechanical devices. The compacted block material may be surrounded by a decomposable paper casing, which is laid in successively as a lining hose of air permeable paper. The compacted material can be delivered as a compact string (46) by successive projection movements of the suction chamber (28) for being cut into blocks (56), and the suction chamber can be temporarily opened for free return movements into its initial position.

Description: A method and a system for producing block bodies from loose material such as sphagnum. The present invention relates to a method of pro¬ ducing substrate blocks, primarily small blocks of sphagnum for the growing af cuttings and seed plants, and of the type consisting of a cylindrical block having an envelope of paper or a similar material and and an associated filling of sphagnum or a corresponding sub¬ strate material. Such blocks can be produced by extru¬ sion of a substrate string that is introduced into a casing tube and cut into pieces of suitable length, and it is common practice that the cylindrical blocks thus produced are mounted in an e.g. vacuum shaped cutting tray of thin plastic, arranged with pockets for receiv¬ ing the blocks, normally with the blocks somewhat up¬ standing from the top side of the tray. When the young plants have grown to a certain extent the substrate blocks are transferred to plant pots having a larger substrate volume, and the casing material is gradually decomposed, such that the plant can then freely grow its roots out in the plant pot. It is already known that for the production of the substrate blocks it is possible to use machines operat¬ ing roughly in the same manner as cigarette machines, but also being correspondingly very expensive, whereby they are entirely out of reach for even very large gar¬ dening enterprises or for only average sized special factories for the production of such blocks. There is an expressed need for cheaper machines for use in average sized enterprises, and here it has been customary to use a machinery operating by axially pressing the substrate material into the casing tube by means of either a con¬ veying worm or a compaction piston. Basically this is a simple technique, which can be applied with relatively very simple means, but for one thing the machinery is rather expensive anyway, and for another thing it is well known to the skilled people that there are noticeable operational difficulties with these machines, because a pressing forward and compac¬ tion of a loose sphagnum like material gives rise to big problems due to the coarse fibrous character of the material. With the use of both a piston and a worm there are frequent operational disturbances and stops, and the cheaper, yet still quite expensive machines in this group are thus largely problematic due to the coarse and sometimes even very coarse structure of the substrate. In connection with the present invention it has been realized that it is possible to effect an opera¬ tionally much safer stowing together of the substrate material in the casing tube with the use of highly simple means, viz. by using suction in stead of pres¬ sing. The casing tube may well be made of air permeable material, this even applying to a here well usable material which has in fact already been used as a casing material, without, however, the said property of the material having been paid particular attention or utilized in connection with the filling in of the sub¬ strate. The casing tube can be advanced through a vacuum zone, in which air is sucked in or rather out with such a capacity that the suction can be brought to propagate axially through a feeder conduit in a manner such that the material may be supplied by suction in from a storage of loose substrate material, while in the suc¬ tion chamber it will be packed together with a force depending of the applied vacuum. This provides for operational conditions quite different from those as¬ sociated with pressing means, as there will be no risk of any jamming. The compaction of the material will take place successively from the suction end of the suction zone, and it has been found that the operational safety can hereby be extremely high. Once the block material has been built up in the suction zone the filled paper tube may be further ad¬ vanced by mechanical means, whereby blocks of a suitable length can be currently cut from the advanced material string, and these blocks may then be transferred for automatic mounting in receiver units such as cutting trays. The invention, which is further defined in the appended claims and also comprises a system for carrying out the method, will now be described in more detail with reference to the drawing, in which: Fig. 1 is a schematic perspective view of a system according to the invention, Fig. 2 is a lateral view thereof, Fig. 3 is an end view of a paper inlet station, and Fig. 4 is an end view of a suction chamber in the system. In the right hand side of Fig. 1 is shown an amount of sphagnum 2 supplied on a conveyor belt 4 forwardly towards the end of a suction funnel 6, which projects from a conveyor pipe 8, optionally in a crosswise movable manner, such that by control means not shown it can be displaced for currently sucking away the arriving sphagnum by the action of a suction blower 10 connected with the pipe 8 further ahead thereof. It is not de¬ cisive how the sphagnum is supplied to the suction pipe 8, when only there is arranged for a preferably con¬ tinuous sucking in. The pipe extends further through a folding zone 12, in which an air permeable paper strip 14 supplied from a storage reel 16 is successively wrapped about the pipe and continues into the pipe through a narrow annular slot 18 so as to form an inner lining hose in the further projecting pipe, designated 20. In a gluing station 22 glue is applied to a joining edge area of this hose, and the glue is set by the hose passing through a heating station 24, such that thereafter the paper web is stabilized in its hose shape for further advancing inside the pipe 20. The introduction of the paper web 14 is also il¬ lustrated in Fig. 3, where it is shown that the pipes 8 and 20 meet so as to form the annular slot 18, holding means 26 being arranged for mutually centered fixing of the pipes in this ares. Thereafter the pipe 20 continues further into a suction chamber 28 designed as a cylindrical housing consisting of two mutually separable half parts having a outer shell 30 and an internal tube or half tube shell 32, these shells 32 in the joined condition of the two half parts forming a perforated tube 34 extending as a prolongation of the pipe 20, though with a slightly larger diameter. As shown in Fig. 2 the pipe 20 is in¬ truding into a part of the perforated tube 34, with light slide fit therein. The suction chamber is suspended in a surrounding frame 36 and is, together with this frame, axially reci¬ procal by means of suitable driving means such as cyl¬ inders 38. The connection between the frame 36 and the suction chamber is established through opposite working cylinders 40 cooperating with the respective halves of the suction chamber, such that these can additionally be controlled to move away from each other, as indicated by dotted lines in Fig. 4. The suction chamber 28 or rather the two halves thereof are connected, through flexible hoses 42, with the suction side of the said suction blower 10, the outlet or pressure side of which is connected with a separator cyclone 44. As further mentioned below, a rigid material rod or string 46 will be formed in the suction chamber 28 and brought forwardly to a receiver tube 48, which continues into a cutting box 50, in which a knife 52 controlled by a cylinder 54 will successively cut the material string for forming it into block bodies 56, Fig. 2. These bodies are conveyed through a funnel member 58 for being received in suitable receptacles, a preferred design of which will be indicated below. In an initial start phase the paper web 14 is in¬ troduced through the annular slot 18 and is 'fished' forwardly to the left end of the suction chamber 28, Fig. 1 and 2. This end is temporarily closed, whereby the suction blower 10 will suck in air through the hoses 42, the wall of the perforated inner tube 34, the wall of the tubular portion of air permeable paper located thereagainst, the interior of the pipe 20 and its con¬ tinuation 8 in front of the annular slot 18, and finally (or rather in the first place) through the outer suction funnel 6. The supplied sphagnum 2 will thus be sucked forwardly for being deposited in the suction chamber 28, where the sphagnum is positively compacted at the left hand end and therefrom further to the right. Hereby a rigid string 46 of paper wrapped, compacted sphagnum will be built up. After this initial starting phase the cylinders 38 are actuated for pushing the suction chamber 28 towards the cutting box 50, whereby the suction chamber, bring¬ ing along the sphagnum string as compacted therein, causes this string to be introduced into the inlet tube 48 on the cutting box 50, while also causing the sur¬ rounding paper casing to be advanced and thus also the paper web 14 to be drawn forwardly and into the pipe 20 through the annular slot 18. Thereafter the cylinders 40 are actuated to draw the half parts of the suction chamber from each other, i.e. to the positions shown in dotted lines in Fig. 4, in which the inner, perforated tube portions 32 fully leave their engagement with the formed string 46, and then the cylinders 38 are actuated for returning the thus separated half parts of the suction chamber into their initial positions, in which they are again brought together by means of the cylinders 40. Now the compacted material string 46 as emerging from the left hand end of the suction chamber will form a practically airtight plug against air being sucked in from this end of the suction chamber, such that thereafter the said temporary closing of this end will no longer be required. New material 2 will be sucked in for compaction in immediate continuation of the string portion 46 which has already been projected from the suction chamber 28, and it will be appreciated that in this manner, by successive move¬ ments of the half parts of the suction chamber, it is possible to achieve a stepwise projection of the paper wrapped material string 46 to the cutting unit 50. The material is introduced at the right hand end of the perforated tube 36 of the suction chamber as the tube 36 is moved forwardly over the end of the pipe 20, and this movement is to be stopped just before the suc¬ tion chamber would hereby leave this pipe end, confer the suction chamber position shown in dotted lines in Fig. 2. The suction chamber should not be opened until the material has been compacted all over the length of the chamber and a short distance into the mouthing of the pipe 20, viz. such that the material string 46 will be self carrying between the mouthings of the pipes 20 and 48 when the suction chamber is opened for its return movement; it could be a possibility, however, that the string should not be fully self-carrying, as the lower half part of the suction chamber could be left unlowered by the returning of the suction chamber. It is a theoretical possibility that the suction chamber could be left unopened or unseparated, such that it should not have to be movable or divided in separate halves, viz. if the conveying of the material string 46 is effected by separate means in front of the front end of the suction chamber, e.g. by driving means including toothed wheels, the teeth of which intrude directly into the side of the string 46; it will not be very important if the paper casing is hereby widely damaged, but it has been found that it is difficult in this manner to achieve a well defined conveyance of the string 46, because of a pronounced friction between this string and the inner side of the perforated tube 36. It is this friction which is utilized for the already described, preferred conveying method. With reference to the above it can be of importance to determine when the perforated tube 36 has been en¬ tirely filled out by compacted material. This may be determined iteratively, but also with the use of a sub pressure gauge connected to the suction connection be¬ tween the suction blower 10 and the suction chamber 28; the applied sub pressure will rise noticeably when the material has been compacted to such an extent that the further sucking in of air is blocked essentially. In principle, the delivery of the cut block members 56 may take place directly to respective receiver open¬ ings in receiving trays which are displaced stepwise and laterally in front of the cutting unit 50, but in prac¬ tice this has been found less attractive. In stead it is preferred, as shown in Fig. 1, to drop the cut block members 56 through the spout portion 58 such that they fall down into funnel members 60 carried by supporting means 62 conveyed chainlike along a path 64 crossing over a longitudinally extending conveyor 66, which car¬ ries along the said receiver trays 68 having receiving pockets 70. Above the conveying path of the supporting means 62 there is provided a push-down station 72 with pusher pistons 74, which, by means of a working cylinder 76, are operable to push down the block members 56 into the respective receiver pockets 70 in the underlying trays 68 as conveyed on the conveyor 66. The push-down pistons 74 are able to surpass the pressure necessary for pressing the block members 56 downwardly out of the funnel members 60. In the cutting station 12 the effective cutting means may be a circular saw, but in practice it will be preferred to make use of more adjacent, parallel process lines for concurrently filling substrate blocks into more tray pockets, and if so it will be suitable to use a rapidly reciprocal saw blade, which can cut more sub¬ strate strings at a time by a unitary cross feed of the saw blade. The compactness of the formed block substrate is highly depending of the applied suction pressure, and it can be suitable to make use of a pressure regulator 43, either for a production of blocks having a varying den¬ sity or for adjusting the density when the quality of the raw material varies. For successful tests of the principles of the in¬ vention an ordinary household vacuum cleaner has been used in connection with a 40 mm suction pipe, i.e. it has proved sufficient to use a simple suction blower as distinguished from a real vacuum pump. Of course, sever¬ al production strings would be serviceable from a common suction blower. The building up of the block string af sphagnum or other substrate material may of course take place also without any preceding introduction of the air permeable web and casing material, though in that case the tube 34 in the suction chamber 28 should be finely perforated, and in some cases it is acceptable to deliver the string or block material without the surrounding envelope. Alternatively a casing material may be applied in con¬ nection with the block string leaving the tube after the chamber 28. It is a further possibility that the chamber 28 and its downstream tube outlet can be arranged with a cer¬ tain directional break from the direction of the preced¬ ing feeding pipe, whereby it would be possible to use a piston in connection with an external working cylinder for pressing out the material from the chamber region, without the latter being opened. It should be mentioned that the technique according to the invention may well be used for similar block formation of materials other than sphagnum, also for other purposes.

Claims: C L A I M S : 1. A method of manufacturing substrate blocks from a loose material such as sphagnum, characterized in that the material is sucked in through a pipe for deposition in a suction chamber connected with a suction source through a perforated sieve wall, and that the resulting, compacted material collected in the suction chamber is continually or blockwise let out from the suction chamber. 2. A method according to claim 1, whereby in con¬ nection with the letting out of the material there is steadily left a material plug in an outlet conduit of the suction chamber. 3. A method according to claim 1 for producing block members surrounded by a tubular sheet or paper casing, characterized in that a web of an air permeable sheet/paper material is currently introduced through a slot in the suction pipe and the web is guided so as to form a lining pipe in the end portion of the suction pipe part facing the suction chamber, said lining pipe currently being let out from the chamber together with the discharged block material as housed in the lining web. 4. A method according to claim 1, whereby for ad¬ vancing the wrapped material string the suction chamber is moved forwardly in a non-divided condition, while it is thereafter returned freely in a divided condition, back to its starting position for renewed advancing of the material string with the suction chamber in a non- divided condition. 5. A system for carrying out the method according to claim 1, characterized in that it comprises a suction pipe for for sucking in a loose material to a perforated tube member in a suction chamber provided around this tube member and and connected to an external suction source, and means for discharging the sucked in and compacted material from said tube member. 6. A system according to claim 5, in which the discharging means comprise the suction chamber itself, this chamber being arranged in an axially reciprocal manner and being openable in such a manner that after having advanced the material string it can freely return into its starting position, where it is reassembled. 7. A system according to claim 5, in which the suction pipe is designed so as to allow an air permeable paper or sheet web to be introduced through the pipe side for currently forming an axially movable lining pipe inside the suction pipe. 8. A system according to claim 5, in which a suc¬ tion pressure regulator is provided between the suction source and the suction chamber.

Inventors: ELLEGAARD OEYVIND, ELLEGAARD, OEYVIND
Applicants: ELLEGAARD OEYVIND, ELLEGAARD, OEYVIND
Application year: 1991
Main classification: A01G9
IPC codes: A01G1, A01G9