IL44611A - Bag for transporting bulk material - Google Patents

Description

γ A BAG FOR BULK MATERIAL This inven ion relates to containers for bulk particularly for The use of large bags transporting bulk quantities of powdered or granular materiel is and it is known use bags of a disposable In such bags the base of the bag is usually and the top of the bag is with a drawstring encompassed by the fabric of the bag except at four corner The drawstring thus forms four lifting loops at these In use the bag is loaded through the open mouth and then lifted by way of the The drawstring effect closes the south of the To bag this is suspended by the loops over the receiving area and the bottom of the bag is cut away to allow the material to fall The disadvantage with this type of bag is that when the bag is by the loops very high stresses occur at the points where the drawstring enters the encompassing fabric at the fur This can result in early failure of the bags and gives a low factor of This is generally about with a bag designed a load of one According to the present invention there is provided a bag for transporting bulk the bag four separate lifting loops disposed around the each loop having a bight and two spaced and each leg being secured to the by folding a section of the to a substantially configuration along fold lines extending from the top towards the bottom of the bag and stitching through the three thicknesses of fabric and the In a bag according to the invention it will be seen each leg of each loop is stitched to a width of bag which is three times the width of the loop As there are eight such legs the total width of bag to which the lifting load is transmitted is 24 times the width of the loop By proper choice of materials it is possible to provide a bag that is no more expensive than existing bags and yet has a much greater equivalent safety The conventional size of bags with which the invention is concerned is designed to carry one tonne of comminuted material To support this weight it is desirable to use loop material which is at least 2 inches wide and to make the bag from material having a tensile strength of at least per linear The lifting load will be transmitted to a total width of bag material of 48 inches and the maximum load supported will be the bag have a safety factor for a tonne load that is similar to that of bags already in the safety factor can readily be raised above this and it is desirable that this should be The proper to lift or suspend bags according to the invention is to engage all four lifting loops to dispose them substantially it must be recognised that mishandling can occur and that a loaded bag may be engaged on one loop this leads to a requirement of a minimum safety factor of and desirably somewhat above Accordingly the tensile strength of the bag material is preferably at least per linear these change if the can be reduced if the material loop width is increased above 2 inches Conveniently the material of the bag is woven from a high tenacity synthetic for example nylon and mixtures It may be possible to use a strong natural such as but generally synthetic fibres are stronger and more resistant to A particularly preferred for the bag is 15 x 15 inch woven polypropylene of 2000 which is relatively cheap and possesses the required Polypropylene has a tensile strength of per denier a single 2000 denier tape will thus support With a weave of 15 tapes per inch the tensile strength per inch is thus 150 well above the preferred minimum figure of With 48 inches of material taking load the maximum supported load will be giving a safety for a tonne load of significantly higher than that of conventional even though the bag is no more expensive than conventional To maintain the safety factor give by the bag material it is obviously desirable to choose loop material giving the same safety the absolute minimum breaking load of the loop material be 600 the preferred minimum being 1000 The material of each loop is preferably woven terylene of the type used for vehicle seat A two inch width of this has a breaking load of so that lifting loops will give a total load capacity of a safety factor of thus making such material particularly suitable for use with the woven polypropylene described The method of attachment of the loops obviously necessitates a gathering in the material over the upper part of the and the resultant shape is advantageous from a stability view The top of the bag is preferably provided with a cover stitched to the fabric of the bag the cover having a central opening which may be closed by a drawstring to protect the material in the In order that the invention may be better understood a specific embodiment of a bag made i accordance therewith will now be described in more with reference to the accompanying drawings in Figure 1 is a schematic perspective view of a and on the line of Figure 1 Figure 2 is a a loop stitched to the The bag is formed with a body 1 having a substantially square the preferred fabric for the body and base being 15 x 15 per sqv inch woven polypropylene of 2000 Towards the top of the body the fabric is gathered and four lifting loops 2 to 5 are secured to the Each loop loop comprises a bight 6 and two legs 7 and Each leg is secured to the fabric of the bag body by folding the fabric around the leg and then back upon itself spaced legs 7 8 overlie the bag fabric 1 and is folded back over the respective legs to give sections 10 and then folded back upon itself to give a section Each leg is secured to the fabric by stitching 12 through the three thicknesses of bag fabric and through the material of the The material used for the loops is preferably terylene webbing as used for vehicle seat With webbing two inches wide it will be seen that a six inch width of bag fabric is stitched to each leg and the total width of bag fabric available to take the transmitted load from the loops is The bag includes a cover stitched to the bag fabric around the mouth at the upper end and the cover has a drawstring 14 surrounding a central The bag shown may be lined with a detachable or fixed which may for example be of to prevent migration of fine particles of powder through the fabric of the bag the bag as shown has been and the drawstring of the cover the bag may then be lifted by the A number of bags may be stacked one on top of with the bottom of one bag lying on the cover The squat profile of the bag leads to good and the loaded bag carries well by suspension from either a crane or a fork lift A bag designed to carry one tonne of powdered material would have a base approximately square and a height of 50 If made from the preferred materials described bag will have a safety factor of As described the bag is not reusable after the bottom has been cut to release the A reusable bag may made however by cutting a hole may be round or in the hemming the cut edges to prevent tearing of the material and laying a sheet of heavy gauge polyethylene or other sheeting over the hole and surrounding part of the base of the Material can then be loaded into the bag providing the ratio of total base area to area of the hole in the base is above certain minimum determined the pressure of the material on the floor of the bag surrounding the hole maintains sufficient in the sheeting to prevent it from being pushed out of the To empty the bag the is and a new piece of sheeting is put in the bag before a further modification the bag may be formed with a drawstring closure at the although this is expensive it does have the added advantage of giving a degree of control over the from the insufficientOCRQuality

Claims (6)

1. IH611/2

2. Claims; 1 · A bag for transporting bulk material, the bag having a top and having four separate li ting loops disposed around the top, each loop having a bight and two spaced legs, and each leg being secured to the fabric by folding a section of the fabric to a substantially S-shaped configuration along fold lines extending from the top towarda the bottom of the bag and stitching through the three thicknesses of fabric and the leg* 2* A bag according to claim 1 in which the material of each loop is at least 2 inches vide and the material of the bag has a tensile strength of at least 50 kg* per 1linear inch*

3. * A bag accordin to claim 2 in which the material of the bag hss a tensile strength of at least 83*3 kg* per linear inch*

4. . A bag according to claim 2 in which the material of the bag has a tensile strength of about 150 kg* per linear inch*

5. * A bag according to any one of the preceding claims in which the material of the bag is woven from a high tenacity synthetic fibre*

6. * A bag according to claim 5 & Which the material of the bag is 15 x 15 per s¾. inch woven polypropylene of 2000 denier* 7· A bag according to any one of the preceding claims in which the material of each loop haa a breaking load of at least 600 kg* 44611 2 8. A bag according to claim 7 in which the material of each loop has a breaking load of at least 1000 kg. 9. A bag according to claim 7 in which the material of each loop has a breaking load of about 1810 kg. 10. A bag according to any one of the precedin claims in which the material of each loop is woven polyethylene terephthalate· 11. A bag according to any one of the preceding claims in which the top of the bag is provided with a cover stitched to the fabric of the bag, the cover having a central opening which may be closed by a drawstring. 12. A bag for transporting bulk material, substantially as herein described and as shown in the accompanying drawings.