PROCESS AND APPARATUS FOR LINE PRODUCTION OF PLANT GROWTH MEDIUM POTS OR BAGS

Abstract

A process for line production of plant growth medium pots or bags with a closed bottom end includes the steps of: i) continuously folding the free end of a continuous length of water and air permeable sheet material into a sheet material tube around and beyond a free end of a growth medium feeding tube; ii) forming a first sealing in the sheet material tube; iii) filling the sheet material tube with a measured amount of growth medium; iv) forming a second sealing in the sheet material tube; v) separating the part of the sheet material tube positioned downstream from the second sealing to form a first plant growth medium pot or bag with a closed end, repeating as needed to form a plurality of plant growth medium pots or bags.

Claims

1. A process for line production of plant growth medium pots or bags (30) with a closed bottom end and an open top end comprising the steps of: i) continuously folding the free end of a continuous length of water and air permeable sheet material (10), preferably supplied on a reel (20), into a sheet material tube (12) around and beyond a free end of a growth medium feeding tube (208); ii) forming a first sealing in the sheet material tube (12) by engaging and flattening the opposed walls of the sheet material tube (12) at a position beyond the free end of the growth medium feeding tube (208); characterized in that the method further comprises the steps of: iii) through the free end of the growth medium feeding tube (208), filling the sheet material tube (12) with a measured amount of growth medium (34); iv) forming a second sealing in the sheet material tube (12) by engaging and flattening the opposed walls of the sheet material tube (12) at a position above the position of the growth medium (34); v) separating the part of the sheet material tube (12) positioned downstream from the second sealing to form a first plant growth medium bag (30) with a closed end and an open top end; and optionally vi) repeating the steps i), and iii)-v) several times to form a plurality of plant growth medium bags (30) with a closed end and an open top end.

2. The process according to claim 1, wherein the continuous length of water and air permeable sheet material (10) is advanced by grabbing the first sealing in the sheet material tube (12) and pulling the first sealing further away from the free end of the growth medium feeding tube (208).

3. The process according to claim 1, wherein step i) comprises sealing the overlapping sheet side parts to one another.

4. The process according to claim 1, wherein the water and air permeable sheet material (10) comprises a) fibers coated with a thermoplastic material and/or b) fibers of a thermoplastic material; and wherein the sealings are made by heating.

5. The process according to claim 1, wherein the growth medium feeding tube (208) is connected to a growth medium delivering unit comprising: a storage container (204) adapted for holding growth medium, and with an outlet (205) in the bottom wall; a stirrer (230) configured to maintain the growth medium homogeneous in the storage container (204); and an open-ended dosing chamber (210) configured to move between a first position and a second position; wherein a first open end (211) connects to the outlet (205) of the storage container (204) in the first position, and wherein a second open end (213) connects to an inlet of the growth medium feeding tube (208) in the second position, while the first open end (211) disconnects from outlet (205) of the storage container (204), thereby removing a dosage of growth medium from the storage container (204), through the open-ended dosing chamber (210), and into the growth medium feeding tube (208).

6. A growth medium pot or bag (30) obtainable by the process according to claim 1.

7. A growth medium pot or bag (30) with a closed bottom end and an open top end, the growth medium pot or bag comprising a tubular sheet material (32) having two sides, and two ends, and surrounding a portion of growth medium (34); wherein the tubular sheet material (32) is made of a single sheet of water and air permeable sheet material being sealed with two seals formed in said sheet material; wherein a first seal (36) of the two seals is a lap seal joining the two sides of the sheet material to form a tube; and wherein a second seal (38) of the two seals is formed in one of the ends of the tubular sheet material (32) by engaging and flattening the opposed walls of the sheet material tube.

8. An apparatus (100) for use in the process according to claim 1, the apparatus comprising: a storage container (200) adapted for holding growth medium, and comprising a growth medium feeding tube (208) with a free end; wherein the storage container (200) is adapted for delivering dosages of growth medium through the growth medium feeding tube (208); folding means (300) adapted for continuously folding the free end of a continuous length of water and air permeable sheet material (10), preferably supplied on a reel (20), into a sheet material tube (12) around the growth medium feeding tube (208); a suction chamber (400) adapted to be positioned around and beyond the free end of the growth medium feeding tube (208), and adapted to be in a) an open first configuration and b) in a closed second configuration; wherein when in the closed second configuration the suction chamber (400) encloses the free end of the growth medium feeding tube (208) and the sheet material tube formed around it, and engages and flattens the opposed walls of the sheet material tube at a predefined distance downstream from the free end of the growth medium feeding tube (208); and subsequently removes air out of the suction chamber (400), such that a dosage of growth medium in the storage container (200) is transported through the growth medium feeding tube (208) and into the sheet material tube within said suction chamber (400); a first sealing means (500) adapted for forming a sealing in the sheet material tube by engaging and flattening the opposed walls of the open end of the sheet material tube at a position downstream to the suction chamber (400); wherein the free end of the growth medium feeding tube (208) is configured with one or more perforations or slits (209) extending through its walls; and cutting means (700) adapted for separating a formed plant growth pot or bag (30) from the continuous length of water permeable sheet material (10) by cutting downstream from the sealing to form a plant growth pot or bag (30) with an open top end and a closed bottom end.

9. The apparatus (100) according to claim 8, further comprising a second sealing means (610) adapted for lap sealing the sheet material tube.

10. The apparatus (100) according to claim 9, wherein the second sealing means (610) comprises a welding jaw (610), and wherein a part of the free end of the growth medium feeding tube (208) comprises a protrusion (620) adapted for receiving said welding jaw (610).

Description

BRIEF DESCRIPTION OF THE FIGURES

[0055] FIG. 1 shows an apparatus for use in the process in accordance with various embodiments of the invention;

[0056] FIG. 2 shows a part of the storage container in accordance with various embodiments of the invention;

[0057] FIG. 3 shows an example of how to fold the sheet material into a tubular sheet material;

[0058] FIG. 4 shows the suction chamber relative to the free end of the growth medium feeding tube in accordance with various embodiments of the invention; and

[0059] FIG. 5 shows parts of the apparatus for sealing, pulling, and cutting of the tubular sheet material.

DETAILED DESCRIPTION OF THE INVENTION

[0060] FIG. 1 shows an apparatus 100 for line production of plant growth medium pots or bags.

[0061] The apparatus comprises a storage container 200 with a growth medium feeding tube 208 (partly shown), folding means 300, a suction chamber 400 (shown in a closed position), and a first sealing means 500 (partly, only one of the two welding jaws may be seen).

[0062] The storage container 200 is here shown with two storage chambers, a first storage chamber 202 adapted for holding a large amount of growth medium, and a second storage chamber 204 for holding a relatively smaller amount of growth medium. Growth medium is transported from the first storage chamber 202 to the second storage chamber 204 by a conveyor belt 206. In FIG. 2, the second storage chamber 204 is shown relative to an open-ended dosing chamber 210. The open-ended dosing chamber 210 is configured to move between a first position and a second position with the aid of a pneumatic/hydraulic cylinder 212, as indicated by an arrow. A first open end 211 of the open-ended dosing chamber 210 connects to the outlet 205 of the second storage chamber 204 in the first position, and wherein the second open end 213 (not shown, but indicated by an arrow) connects to the inlet of the growth medium feeding tube 208 in the second position (here shown in the second position), while the first open end 211 disconnects from outlet 205 of the second storage chamber 204, thereby removing a dosage of growth medium from the second storage chamber 204, through the open-ended dosing chamber 210, and into the growth medium feeding tube 208. The storage container 200 further comprises a piston 220 configured to move through the first 211 and second 213 open ends of the open-ended dosing chamber 210 when the open-ended dosing chamber 210 is in the second position. This piston is not necessary when producing larger pots or bags. A stirrer paddle blade/head 230 is configured as two cylindrical rods extending radially away from the stirrer shaft. This configuration is to avoid demixing of the growth medium.

[0063] FIG. 3 shows an example of how to fold the sheet material into a tubular sheet material. The folding means 300 is adapted for continuously folding the free end of a continuous length of water and air permeable sheet material 10 supplied on a reel 20, into a sheet material tube (not shown) around the growth medium feeding tube 208. The folding means 300 is here shown comprising two ring- or tube-shaped units. The upper tube-shaped unit 310 is a guide means adapted for securing that one side of the sheet material 10 is continuously positioned below the other side of the sheet material 10 in order to position the sides relative to each other for a lap seal to be formed. The lower ring-shaped unit 320 is adapted to form the sheet material tube. Both units are positioned around the growth medium feeding tube 208 that thereby also aids in the folding operation. The free end of the growth medium feeding tube 208 is configured with two slits 209 (only one is shown) extending through its walls. The two slits secure that the part of the sheet material tube that extends beyond/below the free end of the growth medium feeding tube 208 will not collapse during the filling operation. Otherwise, the dosage of growth medium would not be able to be correctly positioned therein.

[0064] FIG. 4 shows the suction chamber 400 relative to the free end of the growth medium feeding tube 208 in accordance with various embodiments of the invention. The suction chamber 400 is positioned around and beyond the free end of the growth medium feeding tube 208, and adapted to be in a) an open first configuration (as shown) and b) in a closed second configuration. In the closed second configuration, the suction chamber 400 encloses the free end of the growth medium feeding tube 208, and the sheet material tube (not shown) formed around it. Furthermore, it engages and flattens the opposed walls of the water and air permeable sheet material tube at a predefined distance downstream from the free end of the growth medium feeding tube 208; and subsequently removes air out of the chamber (e.g. by the aid of a pump as seen to the right side in FIG. 1), such that a dosage of growth medium in the dosing chamber 210 and/or in the growth medium feeding tube 208, is transported through the growth medium feeding tube 208 and into the sheet material tube within said suction chamber 400. The free end of the growth medium feeding tube 208 is configured with multiple perforations 209 (three are shown) extending through its walls. The perforations secure that the part of the sheet material tube that extends beyond/below the free end of the growth medium feeding tube 208 will not collapse during the filling operation. Otherwise, the dosage of growth medium would not be able to be correctly positioned therein. A second sealing means is configured for sealing the sheet material tube along its length, here a lap sealing. The lap sealing is made on the sheet material tube when it passes over the growth medium feeding tube. The second sealing means comprises a welding jaw 610, and wherein a part of the free end of the growth medium feeding tube comprises a protrusion 620 adapted for receiving said welding jaw 610. Thereby, a part of the free end of the growth medium feeding tube 208 serves as a part of the second sealing means.

[0065] FIG. 5 shows parts of the apparatus for sealing, pulling, and cutting of the tubular sheet material. The first sealing means 500 (here configured as two welding jaws) is adapted for forming a sealing in the sheet material tube 12 by engaging and flattening the opposed walls of the open end of the sheet material tube 12 at a position downstream to the suction chamber (not shown). The sealing is performed while the suction chamber is in the closed second configuration. When the two welding jaws retract, the suction chamber moves to its open first configuration, and the continuous length of water and air permeable sheet material is advanced by grabbing and pulling means 800 configured for grabbing the formed sealing in the sheet material tube and pulling the sealing further away from the free end of the growth medium feeding tube (not shown). The advantage of grabbing the sealing is to avoid that the sheet material brakes during the pulling operation. The grabbing and pulling means 800 is here shown comprising to jaws 810, 820 adapted for grapping the sealing. The jaws 810, 820 are shown grabbing the sealing, while the two welding jaws are in a retracted position.

[0066] A cutting means 700 is also shown in a retracted position. The cutting means is adapted for separating the formed plant growth pot or bag 30 from the continuous length of water permeable sheet material. The cutting operation is performed subsequently to the pulling operation.

[0067] An example of a growth medium pot or bag 30 produced by the process of the present invention is also shown in FIG. 5. Typical pots or bags prepared by the present invention have a diameter of 20-200 mm, and a height of 20-500 mm. The growth medium pot or bag 30 has a closed bottom end and an open top end and comprises a tubular sheet material 32 surrounding a portion of growth medium 34. The tubular sheet material is made of a single sheet of water and air permeable sheet material being sealed with two seals formed in said sheet material. The first seal is a lap seal 36 joining the two sides of the sheet material to form a tube. The second seal 38 (a tap seal) is formed in one of the ends of the tubular sheet material by engaging and flattening the opposed walls of the sheet material tube.

REFERENCES

[0068] 10 Water permeable sheet material [0069] 12 Sheet material tube [0070] 20 Reel [0071] 30 Plant growth pot or bag [0072] 32 Tubular sheet material [0073] 34 Growth medium [0074] 36 Lap seal [0075] 38 Seal [0076] 100 Apparatus [0077] 200 Storage container [0078] 202 First storage chamber [0079] 204 Second storage chamber [0080] 205 Outlet [0081] 206 Conveyor belt [0082] 208 Growth medium feeding tube [0083] 209 Perforation or slit [0084] 210 Dosing chamber [0085] 211 First open end [0086] 212 Pneumatic/hydraulic cylinder [0087] 213 Second open end [0088] 220 Piston [0089] 230 Stirrer paddle blade/head [0090] 300 Folding means [0091] 310 Upper unit [0092] 320 Lower unit [0093] 400 Suction chamber [0094] 500 First sealing means [0095] 610 Welding jaw/second sealing means [0096] 620 Protrusion [0097] 700 Cutting means [0098] 800 Grabbing and pulling means [0099] 810 Jaw [0100] 820 Jaw