US3831340A

US3831340A - Method for compacting thermoplastic film material and apparatus therefor

Info

Publication number: US3831340A
Authority: US
Inventors: M Tulkoff
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-03-26
Filing date: 1973-03-26
Publication date: 1974-08-27
Anticipated expiration: 1991-08-27

Abstract

There is disclosed a method for compacting thermoplastic film material usually waste film material presenting a rather bulky appearance due to incorporation of air pockets. The waste film is oftentimes in the form of thermoplastic bags of fairly heavy gauge and of fairly large size. The bag is usually the result of use as a means to enclose a stack of a plurality of boxes which have been positioned on a pallet. The bag has been removed and discarded. It is accumulated in a receptacle of relatively large size. The receptacle is constructed of open mesh work on all sides and bottom and possesses a size approximating an area dimension of a pallet and a conventional height of a stack of boxes on such a pallet. The receptacle when loaded with a plurality of the bags is subjected to a heat treatment in an oven which surrounds the receptacle along its sides and top while the receptacle is on the floor, for instance. The oven employed is essentially a housing having an open bottom with a plurality of electric heating elements positioned internally with respect to the inner walls thereof. The oven is relatively movable to encompass the bag containing receptacle. The bags are melted or fused within the receptacle during its dwell time in the confines of the oven. To prevent sticking of the bags to any of the surfaces of the receptacle, at least the inside of the receptacle is given a coating treatment with a plastic release material for instance.

Description

United States Patent 1 1 Tulkoff [451 Aug. 27, 1974 [76] Inventor: Martin J. Tulkoff, 1020 East Lomard St., Baltimore, Md. 21202 22 Filed: Mar. 26, 1973 [21] Appl. No.: 344,624

[52] US. Cl 53/24, 53/25, 53/127,

219/385 [51] Int. Cl. B651) 1/24 [58] Field of Search 219/385, 354, 388, 406,

219/521, 535; 53/27, 29, 30, 184, 24, 25, 127; 100/38, 93 P; 264/D1G. 69

[56] References Cited UNITED STATES PATENTS 2,741,009 4/1956 Slayter et a1 53/127 X 3,012,125 12/1961 Woolhouse 219/385 3,214,798 11/1965 Cook 100/38 X 3,283,469 11/1966 McBrady et a1. 53/184 X 3,312,811 4/1967 Shanklin 219/388 3,581,458 6/1971 Gustavsson 53/30 3,589,102 6/1971 Zelnick 53/184 3,662,512 5/1972 Zelnick .53/30 3,702,920 11/1972 Taylor 219/521 X 3,723,708 3/1973 Tulkoff 219/385 3,745,915 7/1973 Rehm 53/25 X Primary Examiner-Travis S. McGehee Attorney, Agent, or FirmEric P. Schellin; Martin P. Hoffman 1 1 ABSTRACT There is disclosed a method for compacting thermoplastic film material usually waste film material presenting a rather bulky appearance due to incorporation of air pockets. The waste film is oftentimes in the form of thermoplastic bags of fairly heavy gauge and of fairly large size. The bag is usually the result of use as a means to enclose a stack of a plurality of boxes which have been positioned on a pallet. The bag has been removed and discarded. It is accumulated in a receptacle of relatively large size. The receptacle is constructed of open mesh work on all sides and bottom and possesses a size approximating an area dimension of a pallet and a conventional height of a stack of boxes on such a pallet. The receptacle when loaded with a plurality of the bags is subjected to a heat treatment in an oven which surrounds the receptacle along its sides and top while the receptacle is on the floor, for instance. The oven employed is essentially a housing having an open bottom with a plurality of electric heating elements positioned internally with respect to the inner walls thereof. The oven is relatively movable to encompass the bag containing receptacle. The bags are melted or fused within the receptacle during its dwell time in the confines of the oven. To prevent sticking of the bags to any of the surfaces of the receptacle, at least the inside of the receptacle is given a coating treatment with a plastic release material for instance.

4 Claims, 13 Drawing Figures 'v MYM o. I

PATENTEDAUEZTISH SHEET 1 BF 4 FIG.

METHOD FOR COMPACTING THERMOPLASTIC FILM MATERIAL AND APPARATUS THEREFOR BACKGROUND OF THE INVENTION Thermoplastic film material is being used to a great degree as covering material for packaging small and large items of commerce. Large sheets of solid waste plastic film material have been posing a real disposal problem. The large sheets are difficult to compress into a mangeable shape as large sheets tend to possess pockets of air as they are folded or bunched into a trash receptacle. It is quite easy thereby to rapidly fill a trash receptacle with only a few sheets of relatively heavy gauge thermoplastic film material. The trash receptacle has the bulk but not the weight.

The use of thermoplastic film material has become even more widespread with the advent of the use of bags of such material which are used to encompass a stack of boxes, for instance, on a pallet. The bag is utilized in an upside-down manner and is subjected to heat treatment to thereby heat shrink the bag rather form fittingly about the stack of boxes. Numerous recently issued US. patents have dwelt with this subject at great length. Copending US. Pat. application Ser. No. 254,548 filed May 18, 1972, now US. Pat. No.

. 3,723,708 teaches the concept of employing just such an oven which is moved vertically to enclose a loaded pallet having a heat shrinkable plastic bag thereon to thereby shrink the bag about the load. The so loaded encompassed pallet is transported to its final destination, at which point the bag is removed as by tearing it off. Such bags now constitute bulky light trash which is difficult to dispose. The mentioned US. Pat. No. 3,723,708 is herewith incorporated by reference. Certain improvements have been made over the oven disclosed in application Ser. No. 254,548; these improve ments have been disclosed and claimed in a US. patent application Ser. No. 344,774 filed Mar. 26, I973 entitled: Improved Apparatus for Heat Shrinking Material About a Loaded Pallet, herewith incorporated by reference.

SUMMARY OF THE INVENTION As thermoplastic film in either sheetform or torn bags has become an ever greater problem, the present invention has solved the dilemma by arranging to compact such trash material by employing compaction by heat. In carrying out the invention the trash plastic material is loaded into a receptacle. The receptacle has sides, ends and a bottom of open mesh material to permit the flow of heat and infrared radiation into the interior of the receptacle. The receptacle may also have a closure at its top, also of open mesh material. The receptacle has the area size of a conventional pallet and is raised in a similar manner by conventional skids or casters. The height of the receptacle is about the size of the height presented by a pallet having a load thereon normally encompassed by a thermoplastic bag. The receptacle may have one of many embodiments hereinafter discussed and disclosed at considerable length. The receptacle is filled with bags to a level which may be higher than its uppermost leading edge. The receptacle is then positioned so as to be enclosed in a unique oven as disclosed and taught in the US. Pat.

No. 3,723,708 and further described hereinafter. Suffice it to say at this juncture that the oven has solid insulated sides and likewise insulated top. The oven is open at the bottom. Electric heating elements are positioned interiorly of the ends and sides of the oven, thereby providing a captured heated ambient. The oven is relatively movable with respect to the filled receptacle. Means may be located in the ceiling to compress the bags to a degree so that they are held below the edge of the receptacle when the oven is placed over the receptacle. The bags are fused or melted into a much smaller amorphous mass than was present before the heating step. As a result of the melting of the bags to a much smaller mass, the receptacle is given additional room for more waste torn bags. The receptacle is cycled again and again to a heat treatment during which more and more bags are melted into a solid mass. The receptacle in at least some of the embodiments are provided with means for access to the receptacle to empty it out when desired. Also the receptacle is treated with a material which inhibits the sticking of the melted bags to the bottom or sides of the receptacle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one embodiment of the receptacle for carrying out the practice of the present invention.

FIG. 2 is a perspective view of the arrangement including the oven of the present invention illustrating the operation thereof.

FIG. 3 is a cross-sectional view taken along line 33 of FIG. 2.

FIG. 4 is a side view similar to FIG. 3 with a portion broken away.

FIG. 5 is a cross-sectional view taken along line 55 of FIG. 3.

FIG. 6 is an enlarged fragmentary view taken in cross section showing a corner of the receptacle and of the heating oven, respectively.

FIG. 7 is the same cross-sectional view of FIG. 3 wherein the oven is in heating position.

FIG. 8 is a perspective view of another embodiment of the receptacle of the present invention.

FIG. 9 is a side view of a group of nested receptacles of the present invention.

FIG. 10 is a perspective view of another embodiment of the receptacle of the present invention.

FIG. 11 is a perspective view of another embodiment of the receptacle of the present invention in a blank condition.

FIG. 12 is a side elevation of the embodiment of FIG. 11 wherein a plurality are stacked one above the other.

FIG. 13 is a fragmentary cross-sectional view of a portion of the apertured material of an embodiment taken along line 13-13 of FIG. 1.

DETAILED CONSIDERATION OF THE INVENTION Now, turning to the drawings for a detailed consideration of the invention, attention is initially directed to FIG. 1. It will be noted therefrom that the figure illustrates a rectangularly shaped receptacle ll. The receptacle has a bottom, not shown, end walls 12 and side walls 13. The receptacle possesses skids 14 of the type normally employed on a pallet. The bottom and walls are constructed of a material providing a multiplicity of openings so that there is easy communication between the outside and interiorly of the receptacle.

The receptacle in the embodiment shown has hinged doors and 16 for the top of the receptacle. Each hinged door comprises one half of the top. The material of construction is similar to the other parts, namely, having a plurality of apertures.

In the embodiment shown the forwardly facing end wall 12 constitutes a gate which swings outwardly horizontally on hinges 17. It is latched by a fastening means 18 at one corner of the receptacle. The fastening means may be a hasp, for instance.

The FIG. 1 embodiment is constructed of a grid of wire 20 which is secured to a rectangularly shaped frame constructed of tubular metal 19, for instance. The tubular metal is employed whenever the grid 20 does not possess sufficient strength to be selfsupporting. In place of the tubular metal, angle iron may be employed. The hinges 17 may be attached to the frame at the corner by means of bolts, rivets or welding, for instance. Similarly, the latch may be attached at the other side of the gate by suitable means.

While not shown the receptacle may have suitable braces or cross pieces as a means of giving more rigidity should it be required. The need for additional rigidity depends to a large measure on the thickness of the grid employed.

Similarly, top hinged doors l5 and 16 have their re spective hinges secured to the top of the frame by suitable means. The doors may hang loosely as shown prior to introducing the thermoplastic bags that are to be compacted. The doors are then closed by merely rotating them in the direction of the arrows as shown in FIG. 1.

It is contemplated within the purview of the invention that the grid employed in sides, end walls, top door or doors and bottom be constructed of one of many materials and may take the form of a variety of construction. For instance, the grid may be fabricated from woven wires to produce a pattern of open squares or rectangles. The grid may be fabricated of woven wires to produce a pattern of diamonds as shown, generally, in FIG. 1. The grid may be constructed of conventionally available expanded metal. The grid may also be constructed of what is commonly referred to as cyclone fencing. The grid may also be constructed of sheet metal having apertures cut thereinto. The grid may also be constructed of a series of thin strips to produce a grid which is secured as by welding, for instance. It will be appreciated that many other manner and forms will come to mind as being applicable in carrying out the present invention.

As has been previously stated, the receptacle 11 or container is to be loaded with thermoplastic bags. The thusly loaded receptacle is subjected to a heat treatment which essentially softens the bags to a sufficient degree to collapse them into a relatively small heap. It has been found that the thermoplastic material when softened has an affinity for the metal surfaces of the receptacle so that it will adhere thereto. To avoid adhesion the metal surfaces coming in contact with the thermoplastic bags are coated with a release material. The material applied may be a permanently applied plastic coating such as polytetrafluoroethylene such as Teflon or a polyester such as Dieldrin. FIG. 13 is illustrative of a grid constructed of wire 20 having a coating 21 of a polytetrafluoroethylene. The plastic coating so applied provides excellentv release properties. On the other hand, it has also been found desirable to provide a sprayed-on release coating prior to use of the receptacle. FIG. 8 depicts just such an operation. It will be observed that a conduit 22 extends downwardly into a receptacle, of another embodiment. The conduit terminates in a nozzle 23 adapted to spray a liquid release agent which is either a mineral oil, organic animal fat or any silicone oil. It is also contemplated that the release agent may be applied from an aerosol container under pressure by any one of a number of conventional means well known in the art.

Before discussing some of the other embodiments of the type of receptacle within the consideration of the present invention, it appears appropriate to further elucidate at this point the manner of use of the receptacle already discussed. As heretofore disclosed the receptacle is used to contain a plurality of thermoplastic bags of fairly heavy gauge thermoplastic film material. These bags constitute waste or refuse. They are the result of removal from pallets containing a plurality of stacked boxes which have been covered with the thermoplastic film usually in bag form.

After the receptacle has been filled with such bags, the doors are operated to enclose the receptacle. Usually, the bags are quite cumbersome being filled with pockets of air. The receptacle is dimensioned so that it has the approximate size of a conventional pallet loaded with a plurality of boxes. By being placed on skids 14 as shown in the embodiment of FIG. 1, the empty or filled receptacle may be moved about by means of a conventional forklift truck. When the receptacle is filled as in FIG. 1, the forklift truck is employed to move the filled receptacle to a position beneath an open bottomed vertically movable oven 30 of the type illustrated in copending application Ser. No. 254,548 filed May 18, 1972, now U.S. Pat. No. 3,723,708. FIGS. 2 and 3 clearly illustrate such an oven.

The oven 30 has side walls 31 and end walls 32. A top 33 completes the oven. It does not possess a bottom as this would defeat its unique utilizability. The walls and top are constructed of sheet metal, for instance. Preferably, the construction as clearly shown in FIG. 3, is of the sandwich type with outer and inner lamina of sheet metal and a core of suitable insulation material, such as asbestos.

Inside each of the inner end walls 32 is an elongated electric element 34, shown by dotted lines. The ele- I ment 34 is positioned along the lower portion of the wall. The longest dimension of the heating element is such that it bridges a major portion of the width of the end wall. Further, inside each of the side walls 31 are two elongated electric heating elements 35 also shown by dotted lines in FIG. 1. Two of the heating elements 35 are positioned in approximately the same horizontal plane as the heating elements 34 of the end walls 32. Each of the other heating elements are secured to the inner side wall at the upper portion thereof. The heating elements 35 on each side wall are parallel to one another. Additionally, they are of a length so that each bridges a major portion of the width of the side wall 31.

From FIG. 2 it will be seen that a receptacle 11 having a plurality of empty used thermoplastic bags therein has been located on the floor 36 by a forklift means 37,

(shown in a broken manner) to a control station 40 having suitable electric switches for starting and stopping the operation of the hoist 38. The electric hoist has suitable sensing switches designed to stop the operation when the oven is in its uppermost raised position and when it has come to its lowermost position, that is, when it has come to rest on the floor 36, for instance. Switches are also at the control station for reversing the movement of the oven either at the end of the uppermost position or at the lowermost position or at any intermediate position. Additionally, the control station possesses a selective timer device whereby the period of time when the oven is in the lowermost position can be controlled by presetting the time. The control stamately 250F. A thermostatically operated switch 41 is located in the housing to control a desirable preselected temperature level. The electricity is supplied to the heating elements by a flexible conduit 42 shown in fragmentary form.

In FIG. 2 the oven is shown in partial ascent or descent. However, in FIG. 4, the housing has descended so that it rests on the floor 36 thereby completely enclosing the loaded receptacle. It has been found that with a preset temperature of about 250F, and heating elements drawing about 10.6 KW, a dwell time of ID to minutes is sufficient to bring the load to a temperature which enables it to be melted into an amorphous mass. FIG. 3 depicts the oven, in cross section, in a completely raised position.

For greater assurance that the oven descends in the exact same vertical plane on every occasion, vertical guide upright 43 is provided as more succinctly seen from FIGS. 3, 4 and 5. The upright is seen to be an I- beam which may also structurally help to support the ceiling of a building. A carriage 44 is designed to ride on the four leading edges of the support as can be seen from FIG. 5. With regard thereto the carriage 44 has, generally, a U-shaped frame 45 with the end portion of the

legs

46 and 47 secured, as by welding, for instance, to a side wall 31 of the oven 30. The inner portions of the

legs

46 and 47 have extension means 48 which have journalling means for one end of an axle 49. The other end is suitably journalled at the apex portion of the frame. The axles 49 have journalled thereon wheels 50 which are adapted to ride on the edges of the upright 43. By accurately controlling the movement of the oven 30, suitable markings may be made on the floor to delineate the area in which the receptacle is to be positioned. Several color coded markings may be made to accommodate various sizes of pallets.

FIG. 3 illustrates the oven 30 in a raised position over a positioned receptacle having a plurality of bags loaded therein. In FIG. 4 the oven has been lowered and the loaded receptacle is being subjected to heat treatment.

FIG. 6 shows an enlarged cross-sectional view of the oven with the heating element to show the concave heat reflector 51 therebehind. The heat reflector 51 is constructed of an elongated concave sheet metal and is positioned to direct the reflected heat rays in a general upward direction in the direction of the receptacle as shown. With regard to the heating elements secured to the upper portion of the side walls 31, the reflectors are positioned to direct the raysin a somewhat downward direction. It will be seen that the reflectors are located between the heating elements and the walls of the oven.

FIG. 7 represents a cross-sectional view through the oven 30. As the bottom of the receptacle is also constructed of open mesh-like material, the heat is permitted to penetrate all facets of the receptacle with mini mum interference. It will be seen that the view presented shows the thermoplastic bags in a partially softened condition and has already begun to collapse towards the bottom of the receptacle. It will also be noted that the oven 30 has been modified to include a plurality of pins 53 depending downwardly from the ceiling of the oven. The function of these pins is ingenious. It will'be considered that the receptacle may be filled to a point where the thermoplastic bags are overflowing above the brim of the receptacle. As stated heretofore the-bags are bulky due to pockets of air. As i the oven 30 is lowered into position, the pins 53 are arranged and constructed to push or mechanically assist in compressing the bags to a position below the edge of the receptacle. For instance, in the embodiment of FIG. 3 it will be seen that the ceiling of the oven does not possess compressing pins. However, as the receptacle in the embodiments shown in FIG. 3 has top closure doors, the receptacle may be filled to be above the top edge of the receptacle. While the top doors may not be closed due to the excess quantity of bags the weight of the oven on the doors combined with the weight of the doors themselves will assist in compressing the bags down into the receptacle. It is entirely possible that when an oven is employed having the downwardly depending pins 53, the doors at the top may be totally omitted.

After bags have been melted and thereby compacted into a mass at the bottom of the receptacle, the oven is removed so that the receptacle may be moved away and/or additional bags or thermoplastic film material may be added thereto. This procedure may be accomplished as many times as practicable until the receptacle is filled with a mass of thermoplastic material. Gate 12 then provides access to the interior of the receptacle so thatthe now resultant mass of melted thermoplastic material may be removed.

FIG. 8 illustrates another embodiment of the receptacle of the present invention. It will be seen that instead of providing agate 12, a completely removable partition 60 is employed. The partition is retained in place by a plurality of loops 61 on the sides thereof which are arranged and constructed to sit on complementary hooks 62 on the edge side walls of the receptacle. In this embodiment the partition 60 is liftedoff to provide communication interiorly with respect to the receptacle.

It will also be observed that the receptacle of FIG. 8

does not have the skids 14 as heretofore illustrated but rather possesses a plurality of casters 63 at the bottom corners of the receptacle. In this embodiment the receptacle may be moved about as desired without the necessity of employing a forklift truck, unless it becomes too heavily laden. The casters are of a sufficient size to provide adequate clearance for the tines of a forklift truck.

FIG. 9 depicts yet an additional embodiment of the type of receptacle applicable to the present invention. By sloping the walls inwardly downwardly, it is possible and desirable to nest the receptacles as shown.

The receptacle in FIG. 10 is still another embodiment. It will be noted therefrom that only a single door 64 is used as it is of a size to cover the entire opening of the receptacle. Additionally, the receptacle is on metal frame skids 65 as opposed to the wood skids 14 commonly used in connection with pallet-like structures.

In another embodiment as disclosed by FIGS. 11 and 12, the receptacle is constructed from a foldable blank shown, generally, by reference numeral 66. The receptacle may be easily fabricated by properly folding the blank. The resultant receptacle may be held together by suitable means such as metal clips applied to the corners. Those skilled in the art will, of course, visualize means for adequately securing the parts. H0. 12 is clearly illustrative of a manner of stacking a plurality of blanks prior to use. While a completed receptacle will consume considerable volume, it will be readily appreciated that such is not the case when the receptacles are stored in a blank condition and stacked in the fashion of FIG. 12. y

lt will be seen that the invention here described in considerable detail provides a highly acceptable means and method for the disposal and recycling of waste thermoplastic material.

What is claimed is:

l. A method for compacting bulky convoluted air pocket containing thermoplastic film material comprising establishing a hot zone of at least 240 F. consisting of a confined heated body of air, introducing a quantity of the said film material into a receptacle having a plurality of openings along all of its surfaces, then relatively moving said hot zone and said receptacle whereby said receptacle is introduced into said hot zone and the contents therein are subjected to the said body of heated air in said hot zone, maintaining said receptacle in said hot zone for a period of time sufficient to fuse said film material into a mass, thereafter separating said hot zone and said receptacle.

2. The method of claim 1 wherein the film material comprises thermoplastic film material in the form of waste bags.

3. The method of claim 2 wherein the additional step is included of adding additional film material to .the mass in the receptacle and again subjecting the receptacle to said hot zone.

4. The method of claim 2 wherein the bags are subjected to mechanical compression while the receptacle is in the hot zone.

Claims

1. A method for compacting bulky convoluted air pocket containing thermoplastic film material comprising establishing a hot zone of at least 240* F. consisting of a confined heated body of air, introducing a quantity of the said film material into a receptacle having a plurality of openings along all of its surfaces, then relatively moving said hot zone and said receptacle whereby said receptacle is introduced into said hot zone and the contents therein are subjected to the said body of heated air in said hot zone, maintaining said receptacle in said hot zone for a period of time sufficient to fuse said film material into a mass, thereafter separating said hot zone and said receptacle.

3. The method of claim 2 wherein the additional step is included of adding additional film material to the mass in the receptacle and again subjecting the receptacle to said hot zone.