HEAT SHRINK PACKAGING SYSTEM

Abstract

The present apparatus and system relate to a shrink wrap packaging system. The system includes an oven that is a cavity with heating elements positioned inside. A cooling bar traverses the oven. Dies on a conveyor hold packages with shrink wrap sleeves fitted thereon and move the packages through the oven. The cooling bar thermally affects the shrink wrap sleeves such that the sleeves do not immediately begin to shrink as they enter the oven. Rather the cooling bar protects the upper portion of the sleeve such that the entirety of the sleeve shrinks in a more uniform manner as the packages traverse the oven.

Claims

1. A packaging system comprising: a conveyor; a plurality of dies, each die configured to accommodate a package; an oven comprising a cavity with an entrance, and exit, and a heat source disposed within the cavity; a cooling bar that is positioned above the conveyor, in line with a direction of travel of the conveyor, and that traverses at least a portion of the cavity; and the cooling bar having a first end and a second end separated by a length where the second end is arranged closer to the exit of the oven than the first end.

2. The packaging system of claim 1, further comprising: a coolant exchange system connected to the cooling bar and adapted to control the temperature of the cooling bar such that the temperature of the average temperature of the cooling bar is less than the temperature of the oven cavity.

3. The packaging system of claim 2, wherein the cooling bar extends out of the cavity such that the first end of the cooling bar is positioned outside of the cavity while a portion of the length remain inside the cavity, and wherein, when the oven is activated, the first end of the cooling bar is maintained at a temperature that is below a temperature where a shrink wrap sleeve shrinks.

4. The packaging system of claim 1, wherein the heat source is disposed along an interior length of the oven, on either side of the conveyor, and not directly above the conveyor or the cooling bar.

5. The packaging system of claim 1, wherein the cooling bar traverses through the oven and is parallel to the conveyor.

6. The packaging system of claim 1, wherein the heat source and the cooling bar are parallel to the conveyor.

7. The packaging system of claim 1, wherein the cooling bar is hollow and includes a connection at a first end that is connected to a coolant inlet, and wherein the second end is open such that the coolant flows out of the second end.

8. The packaging system of claim 1, further comprising: a package positioned within a die and a sleeve surrounding a top portion of the package such that the height of the cooling bar is such that the sleeve contacts a portion of the cooling bar.

9. The packaging system of claim 1, further comprising: a package positioned within a die and a sleeve surrounding a top portion of the package such that the height of the cooling bar is between one and two millimeters higher than a top-most portion of the sleeve prior to the sleeve shirking.

10. The packaging system of claim 1, wherein the oven is between 60 and 90 centimeters long, and the front of the cooling bar protrudes between 8 and 15 centimeters out of the entrance to the oven.

11. The packaging system of claim 1, further comprising: a package positioned within a die, and a sleeve surrounding a top portion of the package, wherein the package includes at least one protrusion that extends away from the package and toward the sleeve such that the package is asymmetrical about a vertical plane passing through a central axis of the package when the package is positioned within the die.

12. The packaging system of claim 1, wherein the cooling bar is sloped between five and fifteen degrees as it passes through the oven such that the front of the cooling bar is higher than the back of the cooling bar.

13. A packaging system comprising: a conveyor, a cavity containing heating elements, a cooling bar traversing a length of the cavity and positioned above the conveyor; a die positioned on the conveyor and adapted to hold a package fitted with a shrink wrap sleeve; wherein, the conveyor operates to move the die past the cavity such that the heating elements heat at least a portion of a package and shrink-wrap sleeve; and wherein the die positions the shrink-wrap sleeve proximally to the cooling bar such that the uppermost portion of the sleeve is thermally affected by the cooling bar as the package traverses the cavity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a depiction of an embodiment of a preparation section for arranging tubes and sleeves within dies of a conveyor.

[0013] FIG. 2 is a depiction of an embodiment of the exit portion of the oven with the cooling bar arranged within it.

[0014] FIG. 3 is a depiction of an embodiment of the entrance portion of the oven with the cooling bar arranged within it.

[0015] FIG. 4. is a cross-sectional view of block diagram of the cooling bar with dies holding tubes and sleeves passing through the oven (not shown).

[0016] FIG. 5 is a depiction of an embodiment of an enlarged image of a tube with the sleeve shrunken around its exterior.

[0017] FIG. 6 is a perspective depiction of an embodiment of a sleeve sealed around a tube.

[0018] FIG. 7 is a depiction of an embodiment of a tube.

[0019] FIG. 8 is a depiction of an embodiment of the cooling bar positioned at an angle within the oven.

DETAILED DESCRIPTION OF EMBODIMENTS

[0020] Throughout the specification, wherever practicable, like structures will be identified by like reference numbers. Unless expressly stated otherwise, the term or means either or both such that A or B includes A alone, B alone, and both A and B together. Approximately as used herein means rounding to a scientifically significant figure.

[0021] The packaging apparatus is generally two main components. A first portion of the overall machine is a preparation section. In the preparation section, tubes are deposited into the dies of the conveyor, then sleeves are deposited onto the tubes within the dies of the conveyor. A second portion of the machine, the sealing portion, is the oven with cooling bar that shrinks the sleeves onto the tops of the tubes.

[0022] Respecting the preparation section, a conveyor 101 is equipped with one or more dies 102. A tube 103 is placed within the die. Sleeves 105 are placed over the top portion of the tubes. A suction 104 may be used to help position the sleeve over the tube. As the tubes exit the preparation section, a tamper 106 is positioned over the dies of the conveyor and may be used to tamp the sleeve over a tube to assist in proper positioning of the sleeve. The tamper may be in the form of a strip of plastic or metal that lightly brushes the top of the sleeve. A non-stick coating 107 on the bottom of the tamper helps prevent static buildup and ensures the tamper smoothly slides over the top of the sleeve. In the embodiment shown, the tamper is a thin strip of plastic that flexes upward as the tube passes beneath it. The weight of the tamper is sufficient to tamp the sleeve into place.

[0023] The conveyor then carries the tubes and sleeves through the oven. In FIG. 2, the exit of the oven 201 is shown. Within the oven there is positioned one or more heating elements 202. Generally, the oven will have complimentary heating elements on either side of the oven that each radiate heat toward the center of the oven where the tubes pass through the oven. A cooling bar 301 is positioned within the oven, separated from the heating elements and the dies. The cooling bar is raised up, above the passing dies such that there is a gap between the bottom of the cooling bar and the top of the dies. The gap is greater than the height of the tops of the tubes that are protruding from the dies. In the embodiment depicted, the coolant of the cooling bar is air. At the exit of the oven, the cooling bar is open such that air may be flowed through the bar, entering at the entrance to the oven and exiting the cooling bar at the exit of the oven.

[0024] When air is flowed through the bar, the air creates a temperature gradient across the length of the bar. That is, the portion of the cooling bar that is closest to the entrance of the oven is cooler than the portion of the cooling bar at the exit of the oven.

[0025] FIG. 3 depicts the entrance to the oven. Cooling bar 301 extends through the oven. The cooling bar has a first, front end and a second, back end. It is arranged with the front end near the opening of the oven and the back end toward the back of the oven such that the conveyor passes dies under the font end, along the length of the cooling bar, and past the back end. A coolant exchange system is connected to the cooling bar to control the temperature of the cooling bar with respect to the temperature of the oven cavity. Coolant supply line 203 is connected to the one end of the cooling bar. The coolant may be circulated through the cooling bar to keep the cooling bar at an average temperature that is lower than that of the oven. As shown, the cooling bar may extend out of the entrance to the oven. By extending the cooling bar between 8 cm and 15 cm out of the entrance to the oven, the initial contact point between the cooling bar the sleeves remains around room temperature or at least below the temperature at which the sleeves shrink. A secondary tamper 302 may be affixed to the front end of the cooling bar. The secondary tamper may be a piece of flexible film. The flexible film may be a non-stick film that then is also formed into a non-stick coating on the underside of the cooling bar. In another embodiment, the first end (front) of the cooling bar is sloped or curved to eliminate the sharp edge of the cooling bar which could disrupt the placement of the sleeves.

[0026] As noted, the cooling bar is separated from the tops of the dies by a cooling bar height 303. This distance is such that a tube and sleeve may pass beneath the cooling bar. Preferably, the cooling bar height is the same as the height of the unshrunk sleeve so that the top of the sleeve either just brushes the bottom of the cooling bar or almost brushes it. That is the height of the cooling bar is plus or minus 1 to 2 millimeters of the height of the sleeves. If the height of the sleeve is 3 cm., then the height of the cooling bar should be between 2.8 cm and 3.2 cm.

[0027] FIG. 4 is a side view of the sealing portion. The tubes 103 with sleeves 105 are held within dies 102. The top edge of the sleeve brushes along (or approximately one or two millimeters below) the bottom of the cooling bar 301. As the tube passes through the oven, the cooling bar prevents the top portion of the sleeve from prematurely shrinking. For tubes that are approximately 2 cm in diameter, the oven may be between 60 and 90 cm long. After passing through the first quarter of the oven, the heat from the oven begins to shrink the upper portion of the sleeve and simultaneously shrink the lower portion of the sleeve that is around the tube.

[0028] FIG. 5 shows a cross-section finished product, enlarged for reference. As the tubes 103 continue to pass through the oven, the bottom portion 501 of the sleeve 105 becomes fully engaged with the tube and the upper portion 502 continues to shrink around the hinge 503 and lip 504 of the tube and eventually flatten out, fully shrinking over a portion of the top 505 of the tube, leaving a small central circular area 506 of the top of the tube exposed, while completely surrounding and covering the outer circumference of the top. FIG. 6, is a perspective depiction. FIG. 7 is a depiction of a tube without a sleeve. As shown, when the package is held with in the die, the hinge and lip extend away from the sidewall of the package and toward the sleeve. Thus, the package is asymmetrical about a vertical plane of the package passing through the central axis of the package (e.g. a plane along a diameter of the package that does bisect the hinge or the tab) when the package is positioned within the die.

[0029] In one embodiment, the cooling bar is angled upward as it progresses down the length of the oven. From the entry end of the cooling bar to the exit end of the cooling bar, the bar may exhibit an angle of approximately 5 to 15 degrees. The angle of the bar ensures that in the first quarter of the oven, the bar is closer to the tops of the sleeves than it is at the end of the oven. This again assists in initially controlling the temperature at the tops of the sleeves when the tubes enter the oven, but after the bottoms of the sleeves have fully engaged the outer circumference of the tube, more of the heat is allowed to be exposed to the tops of the tube to ensure the tops are fully shrunk over the top of the tube.

[0030] The cooling bar controls the shrinking of the sleeves. Without the cooling bar, the tube affects the shrinking of the bottom portion of the sleeve such that it does not begin to shrink at the same time as the top portion. Instead, the exposed top portion of the sleeve shrinks and deforms first. That causes the sleeve to begin to progress upward on the tube. However, the protruding hinge and tab impede smooth, even upward progression of the sleeve, which then leads to sleeves that are askew and also there can be too much sleeve material overing the top of the tube.

[0031] By equipping the oven with the cooling bar, the cooling bar affects the temperature within the oven at the top portion of the sleeves. This allows the oven to heat the tops and the bottoms of the sleeves more evenly so that the bottoms and tops begin to shrink nearly simultaneously and then fully simultaneously until the bottoms are able to fully engage the outer circumference of the tube. With the bottom portion fully engaged, there is no risk of the sleeve further progressing up the tube. At this point the tubes continue through the oven where the top portion continues to shrink until it flattens out over the top of the tube.

[0032] Although the present invention has been described in terms of various embodiments, it is to be understood that such disclosure is not intended to be limiting. Various alterations and modifications will be readily apparent to those of skill in the art. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the spirit and scope of the invention.