Bagging of compressible bulk material
A method for bagging compressible particle material in bulk compressed form comprising the steps of providing a compressed free standing compressible particle material on a base, providing a bagging apparatus with a stretchable bag having an open mouth with a perimeter smaller than a body perimeter and than a base perimeter when the bag is relaxed, using the bagging apparatus to stretch the bag such that the mouth perimeter becomes larger than the body perimeter and than the base perimeter, enclosing the body in the bag through the open mouth until the body and a top part of the base are contained therewithin, and releasing the bag so that a sufficient memory of the bag allows the bag to provide a compressing force on the top part of the base and body, the body being sealed by the base and bag. A pack of compressible particle material is also disclosed.
1. Field of the Invention
The present invention relates to bulk shipping. More particularly, the invention pertains to a method for palletizing peat moss or the like in bulk compressed form as well as to the palletized product obtained thereby.
2. Description of the Prior Art
Owing to its unique porous structure, peat moss can absorb from about 8 to about 20 times its weight in water. Such a high absorption capacity renders peat moss particularly suitable for use in absorbent products such as diapers, sanitary napkins, tampons and the like. Peat moss is also widely used in horticulture as soil adduct, compost, culture base, etc.
Peat moss is generally packaged in plastic bags for shipment. A typical apparatus for packaging peat moss into bags is described in Canadian Patent No. 1,043,310. The volume of a bag filled with compressed peat moss is usually not larger than about 0.17 cubic meters in order to facilitate handling and shipping. Thus, a single shipment of peat moss may comprise thousands of such bags. The quantity of plastic bags utilized for packaging, and discarded after use, is of course phenomenal and represents a serious threat to the environment.
On the other hand, bulk shipping of peat moss in large containers must be effected rapidly since a prolonged exposure of peat moss to atmospheric oxygen causes a bacterial decomposition of the peat moss. U.S. Pat. Nos. 5,477,658 and 5,699,915 issued to Berger et al. disclose palletized peat moss in bulk compressed form, wherein the peat moss is enveloped in a plastic wrap. However, plastic wrap creates several joints between adjacent plastic layers, which makes it difficult to obtain a sealed package. Although using less plastic than standard small packages, wrapping in bulk still necessitates a considerable quantity of plastic, increasing production costs.
U.S. Pat. No. 3,961,459 to Wolske, U.S. Pat. No. 3,902,303 to King, and U.S. Pat. No. 3,621,638 to Grocke, all discloses machines and methods for packaging palletized loads using stretched plastic bags. However, these machines and methods are adapted for rigid loads, such as boxes, and are thus not adequate for compressible material such as peat moss.
SUMMARY OF THE INVENTIONIt is therefore an aim of the present invention to provide improved palletized peat moss in bulk compressed form.
Therefore, in accordance with the present invention, there is provided a method for bagging compressible particle material in bulk compressed form, the method comprising the steps of providing a compressed quantity of free standing compressible particle material on a base, the compressed particle material forming a body holding a desired shape for a period of time sufficient to permit bagging, providing a bagging apparatus with a stretchable bag, the bag having an open mouth, a mouth perimeter being smaller than a body perimeter and smaller than a base perimeter when the bag is in a relaxed state, using the bagging apparatus to stretch the bag and the mouth so that the mouth perimeter becomes larger than the body perimeter and larger than the base perimeter, progressively enclosing the body in the bag through the open mouth until the body and at least a top part of the base are contained within the bag, and releasing the bag so that a sufficient memory of the bag allows the bag to provide a compressive force on the at least top part of the base and body, the body being sealed in an enclosure formed by the base and bag.
Also in accordance with the present invention, there is provided a pack of compressible particle material comprising a base, a body of compressed particle material in bulk form upstanding freely from the base and compressed directly thereon, and a bag enclosing the body and producing a compressive force thereon so as to retain the compressed particle material in bulk compressed form on the base, the bag and base defining an enclosure completely enclosing the body with the enclosure having a bottom constituted by the base.
BRIEF DESCRIPTION OF THE DRAWINGSReference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment thereof and in which:
In the present invention, Sphagnum peat moss optionally in admixture with mineral or organic aggregates is used as feedstock. The peat moss should have a water-content ranging from about 25 to about 50 weight % and a density ranging from about 0.05 to about 0.15 gm/cc on dry basis. If the water-content is too low, it is adjusted to the desired content by adding water, for example, by means of water sprays.
The peat moss is batch fed to a compression unit for direct compression on a pallet. A predetermined quantity of peat moss is held stacked vertically on the pallet to confine the peat moss to a desired, compressed shape. The peat moss is compressed downwardly onto the pallet at a pressure ranging from about 3 to about 5 kg/cm2 so as to form the peat moss into a coherent, shaped-retaining body without substantially altering the water-content and intrinsic properties of the peat moss. If desired, an additional quantity of peat moss is fed to the compression unit and compressed to increase the amount of peat moss compressed on the pallet. The steps of peat moss feeding and compressing may be repeated several times, although a single compression stroke is preferred. The body of compressed peat moss is then enveloped by a plastic film bag to retain the peat moss in compressed form on the pallet.
As seen in
The compression of the peat moss on the pallet so as to form a shape-retaining body is done according to U.S. Pat. Nos. 5,477,658 and 5,699,915 previously mentioned and incorporated herein by reference. The compression process will be briefly explained herein below.
Referring to
Through a conveyor, the secondary reservoir 22 empties into the compacting station 24 where the peat moss is received in the housing through an open top end thereof. Fork arms extend under the pallet so as to reinforce it during compaction. When the desired quantity of peat moss is transferred into the housing, a piston and cylinder operate to push a ram head downwardly into the housing to compress the peat moss. After the compression stroke, the ram head is raised. The housing is moved from the compacting station 24, where it is opened and then returned to the compacting station 24, thereby exposing the pallet supporting the shape-retaining body of compressed peat moss behind.
The steps of the bagging process are generally illustrated in
Referring to
Referring to
Referring to
Because the peat moss is highly compressible, standard plastic bags used with solid palletized loads are usually not appropriate to form the bag 16. The memory of the plastic, i.e. its capacity to return to its initial shape after deformation, must be sufficient to maintain the peat moss in compression. This is usually not the case in plastic bags used with solid palletized load where the compression force applied by the bag is significantly smaller. Also, the transition from a solid pallet to a soft body of compressed peat moss forms a stress concentration on the bag along that transition, especially around the corners of the pallet. The plastic used thus has to be sufficiently resistant to tearing, typically twice as much as standard plastic used with solid palletized loads, to preserve the integrity of the enclosure protecting the palletized peat moss.
The palletized peat moss 10 contained within a bag 16 presents several advantages over a similar palletized peat moss wrapped in plastic film. First, the elimination of the numerous joints between adjacent plastic layers greatly improves the sealing of the peat moss, thereby improving the shelf life of the packed product. Also, the bag 16 necessitates less plastic material than a wrap, thus reducing the cost of producing the palletized peat moss and the impact of the discarded packaging material on the environment. Bagging implies a single downward motion, while wrapping necessitated several turns around the peat moss body; the bagging process thus takes less time, increasing production. Finally, the appearance of the bagged pallet of peat moss is more esthetically pleasing than a similar wrapped pallet of peat moss.
While the present process has been described with respect to peat moss, it could be applied to a number of granular or small particle materials that can be compressed such as to form a free-standing body. The pallet could also be replaced by any other appropriate rigid base.
The embodiments of the invention described above are intended to be exemplary. Those skilled in the art will therefore appreciate that the forgoing description is illustrative only, and that various alternatives and modifications can be devised without departing from the spirit of the present invention. Accordingly, the present is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.
Claims
1-5. (canceled)
6. A pack of compressible particle material comprising:
- a base;
- a body of compressed particle material in bulk form upstanding freely from the base and compressed directly thereon; and
- a bag enclosing the body and producing a compressive force thereon so as to retain the compressed particle material in bulk compressed form on the base, the bag and base defining an enclosure completely enclosing the body with the enclosure having a bottom constituted by the base.
7. The pack according to claim 6, wherein the compressible particle material is peat moss.
8. The pack according to claim 7, wherein the peat moss has a water-content ranging from about 25 to about 50 weight % and a density ranging from about 0.05 to about 0.15 gm/cc on dry basis.
9. The pack according to claim 6, wherein the bag is made of a fluid-impervious plastic tube sealed at one end thereof.
10. The pack according to claim 6, wherein the base is a pallet.
11. The bag according to claim 6, wherein the bag is stretchable, the bag having a mouth perimeter which is smaller than a body perimeter when the bag is in a relaxed state.
Type: Application
Filed: Mar 16, 2004
Publication Date: Sep 22, 2005
Inventors: Regis Berger (Notre-Dame-du-Portage), Daniel Lebel (Escuminac), Denis Lebel (Gardiner Point)
Application Number: 10/800,746