Packaging apparatus

Abstract

Apparatus and method of packaging liquids wherein an elongated plastic envelope, sealed at one end, is filled with liquid under predetermined static pressure and a selected liquid-filled portion thereof is then heat-sealed and severed from the remainder of the envelope; the liquid being isolated from the heat-sealing and severing zone during such operations to prevent heating the liquid to boiling or gasifying temperatures.

Parent Case Text

This is a division of application Ser. No. 169,439, filed Aug. 5, 1971 now U.S. Pat. No. 3,785,556.

Description

This invention relates generally to packaging, and more particularly, is directed to improved means and method for encapsulating liquids within a heat-sealed plastic package to produce an improved product, particularly useful in disseminating vaporizable liquids.

Various products for purifying, odorizing or deodorizing the atmosphere or for destroying or repelling insects are currently packaged in hermetically-sealed containers. Commonly used containers are either boxes, bottles, destructible plastic film enclosures or the like from which the products, usually in solid or paste form, are removed for use so that the active components thereof may sublimate or vaporize into the atmosphere.

It has been recognized for some time that such a program of diffusing materials of this nature is inefficient and ineffective, particularly over extended periods of time, inasmuch as the relatively high degree of effectiveness thereof, experienced upon first exposing the same to the atmosphere, rapidly diminishes after a relatively short time due to the inability to regulate the rate of dispersion sublimation or vaporization. Attempts have been made to diffuse such materials with controlled rates of vaporization or sublimination. Generally speaking, however, such efforts to date, particularly when dealing with solid materials, have been less than totally effective. In certain other instances, particularly with deodorants, release of liquid deodorizers through capillary wicking systems have proven somewhat more effective and acceptable in controlling the rate of disseminating the ingredients to the atmosphere. Yet, these systems too are incapable of sustaining constant rates of dispersion over extended periods.

It is known that liquid odorants, deodorants, repellents and insecticides, particularly in highly concentrated forms, are highly effective for their intended purposes. However, to date, there has been an absence of a simple, economical and efficient system for releasing the active ingredients of odorizers, deodorizers, repellents, insecticides and the like over extended periods of time so as to benefit from the capabilities of concentrated forms thereof. Foremost in the problems confronting the utilization of such liquids is the problem of diffusing or releasing the same to the atmosphere at a predetermined rate so that the active substances thereof produce their desired effects over extended time intervals. Typifying past efforts to overcome this problem is the invention described in U.S. Pat. No. 2,979,268 issued Apr. 11, 1961, or U.S. Pat. No. 3,216,882 issued Nov. 9, 1965.

In brief, the present invention is directed to improvements in processs, apparatus and product whereby concentrated liquid odorizers, deodorizers, insecticides, repellents and the like may be released to the atmosphere at substantially constant rates for extended time intervals. Essentially the basic scientific mechanism employed, according to this invention, for regulating the rate of release of liquids is that of permeation by which is meant diffusion by absorption not to be confused with porosity or capillarity. This phenomenon of permeability, as herein employed, relates to utilization of plastic films and fluid compounds which are permeant thereto whereby the vapor release of ingredients at the outer surface of the plastic materials after migration of the liquid ingredients therethrough effectively produces an efficient and economical means for releasing the active ingredients of the liquids to the atmosphere. In simplified terms, a body of permeant liquid is encapsulated within a hermetically sealed envelope of a homo-polymer plastic such as polyethylene or polypropylene. When the packaged ingredients are exposed to atmosphere, the permeant liquid releases or vaporizes into the atmosphere at a substantially constant rate dependent primarily on the migration ability of the permeant through the plastic. This permeation rate generally is independent of pressure so that regardless of whether the liquid is pressurized or depressurized within the container it progresses or permeates through the plastic to produce a given quantity output per unit of area. Among other novel aspects of the present invention is the unique system of packaging such permeant liquids within the plastic containers, which preferably comprise an envelope of two superposed plastic layers, hermetically sealed around the borders or margins thereof; the liquid filling the interior of the envelope and disseminating across the interior walls of the package either by capillary activity or direct liquid flow. Essentially, the interior of the envelope is free of any gaseous atmosphere which could affect the output of the permeant liquid. In order to avoid boiling or gasifying the liquid permeant during the heat-sealing operation, which takes place at temperatures in excess of the normal boiling temperatures for the liquids, means are provided for effectively isolating or removing the liquid ingredients from the zone to be heat sealed and/or thermally severed. Thus the liquids are effectively insulated from the undesirable effects created by heat sealing and severing temperatures during the sealing process.

Among the objects of this invention is the provision of an improved procedure for encapsulating liquids in plastic containers, preferably in envelope form.

Another object of this invention is to provide an improved process for thermally sealing liquid-filled plastic containers without boiling or gasifying the liquid during the heat-sealing operation at temperatures in excess of the boiling point for the liquid.

Still another object of this invention is to provide an improved hermetically sealed package containing liquid permeant to the plastic walls of the container.

A still further object of this invention is to provide an improved packaged product of liquid odorant sealed within a plastic container permeable to the odorant, whereby the latter is released from the container at a substantially constant rate for an extended period of time.

Still another object of this invention is to provide improved apparatus for heat sealing a thermoplastic container about a body of liquid.

Having thus described this invention, the above and further objects, features and advantages thereof will be recognized by those familiar with the art from the following detailed description of a preferred embodiment thereof, illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a side elevational view setting forth the features of apparatus for packaging liquids according to this invention;

FIG. 2 is a partial enlarged view in top plan with portions thereof in section taken substantially from vantage line 2--2 of FIG. 1 and looking in the direction of the arrows thereon;

FIG. 3 is an enlarged cross sectional view taken substantially along vantage line 3--3 of FIG. 1 and looking in the direction of the arrows thereon;

FIG. 4 is another enlarged cross sectional view taken substantially at vantage line 4--4 of FIG. 1. and looking in the direction of the arrows thereon;

FIGS. 5, 6 and 7 are enlarged views in side elevation illustrating the sequential steps of heat sealing a plastic container about a body of liquid according to this invention;

FIG. 8 is an enlarged view in side elevation taken substantially from vantage line 8--8 of FIG. 1 and looking in the direction of the arrows thereon; and

FIG. 9 is a perspective view of a package produced according to this invention, showing the same broken open to illustrate capillary distribution means employed therein.

Turning now to the particulars of the particular embodiment set forth in the accompanying drawings for purposes of illustrating and describing the present invention so as to enable those skilled in this art to practice the same, initial reference is made to FIG. 1. As therein shown, apparatus designated generally by numeral 10 is schematically represented for purposes of packaging liquid materials in accordance with the present invention. As set out in this figure, a package tube or blank 11 is formed preferably from two rolls of tape 12, 12' of polyethylene film suitably supported by means not shown, but well within the normal capabilities of one skilled in this art. The width of the tape rolls is generally selected to be just slightly in excess of the desired width for the end packaged product and the two rolls 12, 12' are mounted so as to oppose one another on opposite sides of a filler tube 13. Thus the two layers of plastic 14 and 14' from the respective rolls 12, 12' thereof meet in opposing registration on opposite sides of filler tube 13. The plastic layers extend downwardly along the tube 13 through a sealing and cutting assembly 15 to be described in greater detail presently. Assembly 15 functions both to heat-seal opposite lateral margins of the opposing plastic layers 14, 14' and to trim off excess materials beyond the welded margins; the scrap being removed by periodically actuated roller means 16 according to conventional practice.

The tubular package blank which exits from the sealing and trimming assembly 15 extends below the latter through a fluid level control assembly 18, and into an under-disposed feeding assembly 19. Assembly 19 serves to periodically grip the opposite lateral margins of the tubular package and pull the same downwardly through the sealing and trimming assembly and level control assembly as will be described presently. Beneath the feeder assembly 19, the tubular package 11 passes through a novel heat sealing and cut-off means 20 which serves to produce heat-sealed margins extending transversely between the sealed side margins of the tubular package 11. Means 20 also optionally severs the tube 11 into selected lengths. In this manner, liquid-filled packages are formed from the elongated tubular envelope 11 as will be amplified later herein.

The lowermost end of the tubular package 11 abuts a vertically adjustable stop gauge 21 which by its positioning regulated the vertical dimensions of the liquid-filled packages severed from the tube 11.

With particular reference now to FIGS. 1 and 2, the details of the tube sealing and trimmming assembly 15 will now be described. As best shown in these figures, assembly 15 comprises a supporting bracket 25 having a central anvil portion 26 features by a concave face 27 against which one of the plastic films 14', for example, is shaped during the side margin sealing and trimming operations. Extending laterally outwardly of opposite sides of the central anvil portion 26 are a pair of L-shaped arms 28 and 29, of which only 28 is shown in full plan in FIG. 2. The particulars of arm 28 and related elements will be described with the understanding that arm 29 and its arrangement with the mechanism are identical thereto.

Pivotally connected to the outer end of arm 28 is a knife actuator 30 mounted to pivot about pin means 31. Actuator 30 rocks about the pin 31 in response to periodic energization of a solenoid means 32; being joined to the latter by connector rod 33 which passes through an opening 34 in arm 28 and axially through a return spring means 35 mounted between arm 28 and the adjacent face of the actuator 30. A nut fastener means 36 is threaded over the outer end of the connector rod 33 on the opposite or outer side of actuator 30 to secure the latter to the rod 33 and provide a means for adjusting the arcuate throw of the actuator as deemed desirable. The non-pivotally supported or outer end of actuator 30 is attached by bolt and nut fastener means 37 to a movable hot sealing knife 38 having an electrical heater element 39 near the tip end thereof. Knife 38 opposes a stationary knife 40 adjustably mounted on one side of the central anvil portion 26, as by bolt fastener means 41; the adjustability of knife 40 serving to accommodate varying thicknesses for superposed plastic material of the layers 14, 14'.

As with the movable sealing knife 38, the stationary knife 40 is likewise equipped with a heater element 42 near the outer end thereof to elevate the temperature thereof. In operation, the movable knife 38 is normally at a temperature in excess of that required for sealing the plastic material while the stationary knife 40 is slightly below sealing temperature. For polyethylene, typical temperature for knife 38 are in the order of 320.degree. F. and for the stationary knife 40 in the order of 280.degree. F. As best shown in FIG. 2, a second set of sealing knives 38' and 40' are provided on the opposite side of anvil portion 26 with the movement of the knife 38' being effected by a solenoid operated actuator of the order above described, but not illustrated.

Supported opposite the central anvil portion 26 and located between the hot knives 38 and 38' is a movable anvil member 45 having an arcuately concave face 46 which is adapted to receive and support the second plastic film layer 14. Anvil member 45 is biased normally toward the stationary anvil portion 26 by spring means 47 affixed at one end to a stationary support 48.

In operation, the assembly 15 has the two plastic layers 14, 14' gripped between the anvil portion 26 and member 45 with the filler tube 13, preferably of pliable material disposed therebetween. Periodically the two hot knife blades 38, 38' are moved toward abutting engagement with the stationary knife blades 40, 40'. This occurs upon actuation of solenoid means 32 and its counterpart (not shown) associated with the second set of knife blades 38' and 40'. The hot knife blades press through the two layers of plastic, melting the same until they abut against the stationary knife blades 40, 40', thereby effecting a thermal seal along the lateral margin of plastic layers 14 and 14' held in assembly 15. When the opposing knife blades contact one another they also sever the waste marginal portions 50, 50' of the plastic layers from the central sealed envelope formed between the margin seals. The scrap portions 50, 50' are pulled away by the roller assembly 16 across guide members 51, 51' which are mounted alongside the stationary knife blade members 40, 40'.

In reponse to periodic actuation of the feeding assembly 19, the tubular package member 11, laterally sealed by assembly 15, are periodically indexed or fed downwardly to bring unsealed portions of the plastic layers 14, 14' into assembly 15 where the sealing and trimming operation above described are repeated. It will be appreciated that once the sealing and trimming operations take place, the heated knife elements 38, 38' are withdrawn in response to deenergization of the actuating solenoid means therefor, such as solenoid 32 associated with the illustrated actuator 30. Energization of the solenoid means takes place after each down-feed operation of the tubular member 11 as will appear in greater detail from the description which follows.

The tubular package 11 with its lateral margins now sealed, depends downwardly past the sealing and trimming assembly 15, as hereinabove described, through the level control assembly 18 which will be best understood by examination of FIGS. 1 and 3 of the drawings. From such figures, it will be recognized that a light source 55 is supported to one side of the tubular package member 11 so as to shine toward a photocell 56 located on the opposite side of the package and disposed between the spaced arms of a generally U-shaped guide member 57. Such guide member is adjustably clamped to a support rod 58 depending vertically between upper and lower arm portions 59 and 60 of a C-shaped supporting bracket 61. It will be noted that clamping connection of member 57 with support rod 58 is effected by bolt means 62 which permit adjustable positioning of the guide member 57 and the photocell 56 vertically. Rod 58 is also threadingly fastened at its upper end to arm portion 59 for adjustment purposes, although such adjustments are relatively minor in normal operation.

With the above-described arrangement for the assembly 18, it will be appreciated that when the tube member 11, having the lower end thereof sealed as illustrated in FIG. 1, is filled with liquid up to the level 63 indicated by dotted lines in FIG. 1, the light energy from source 55 is focused by the liquid between the opposing walls 14, 14' of the tube 11 to energize photocell 56. Conversely, when the liquid level falls below level 63, the light rays from source 55 fail to focus on cell 56 and the latter is deenergized. In its energized condition, cell 56, through suitable control circuitry, not shown, but well within the skill of those normally versed with this art, signals a liquid supply source (not shown) associated with filler tube 13 to shut off the supply of additional liquid to the interior of the tube member 11. Conversely, when the cell 56 is deenergized, the liquid supply system is appropriately conditioned to supply liquid to filler tube 13. In this manner, the level of liquid within the tubular package member 11 is maintained substantially constant at level 63 so as to provide a predetermined static head of liquid within the lower regions of the tubular package member 11.

It is to be noted from FIG. 3 in particular that the U-shaped member 57 associated with the liquid level control assembly is provided with a pair of guide elements 64, 64' having substantially V-shaped opposing faces 65, 65' maintained in a spaced opposing relationship and between which tubular member 11 is trained, the apex of each face 65, 65' engaging one of the marginal seals of the package tube 11. The lateral spacing between the V-shaped guide surfaces is by design just slightly less than the distance between the lateral margins of the unfilled tube portion thereabove (depicted in FIG. 2 showing the configuration of the unfilled tube member 11 in assembly 15). As a consequence, the V-shaped guide surfaces 65, 65' serve to bow the tubular member outwardly between the lateral sealed margins thereof, to bring about a generally predetermined spacing and cross section between the opposing walls 14, 14'. This assists in filling the lower portions of the tubular member with a uniform volume of liquid determinative of the desired static head but more importantly the bowed configuration accomplished provides the desired lens for the photocell of the level control assembly. Importantly, of course, it is essential that the lens configuration be uniform for successful operation of the photocell for each downfeed of the package tube.

Located generally beneath the level control assembly 18 and spaced conveniently along the length of the tubular member 11 is the feeding assembly 19 previously alluded to. For a better understanding of this assembly, reference is particularly made to FIGS. 1 and 4. As therein shown, a feeder block 70 is slidably mounted on a vertical cylindrical post 71 supported at its lower end on the lower arm portion 60 of support bracket 61. The block member 70 is movable vertically up and down the post 70 against the action of intervening spring means 72. Normally, spring means 72 serves to bias block 70 to its upper position as illustrated in FIG. 1 which is limited by an enlarged upper end portion of the post 70. An actuator link 73, responsively movable downwardly with energization of a solenoid means 74, also supported on the outer end of the arm portion 60 on bracket means 61, is connected to the feeder block 70 as by a pivot pin.

With this described arrangement, it will be understood that energization of solenoid means 74 serves to pull the block 70 downwardly against the action of spring 72 with the latter returning the block 70 upwardly upon deenergization of the solenoid means 74. It further will be appreciated that the guide rod 71 is located to one side of the rod 58 which supports the liquid level assembly 18.

A second solenoid gripper means 76 is carried in a central opening 77 of the block member 75. The core of the solenoid means 76 is coupled to an actuator rod 78 which extends through an opening in an intermediate wall portion 79 of the block member 70 and is coaxially surrounded by a spring means 80. The outer end of actuator rod 78 is fixed to a movable L-shaped gripper member 81 whereby the latter moves responsibly with the actuator rod 78. In operation, energization of solenoid means 76 serves to move the gripper member 81 to the right as viewed in FIG. 4 or, that is, toward block member 70 with the spring means 80 effecting return movement of the gripper member upon deenergization of the solenoid 76.

The gripper member 81 is slidably supported on the block member 70 by means of a connector pin or rivet 82 extending outwardly of one side 83 of the block member 70 and through a slotted opening 84 (see FIG. 1) formed in a base arm 85 of the L-shaped gripper member 81. The other arm 86 of the gripper member 81 extends at right angles to base arm 85 thereof and is fixed, as previously described, to the outer end of the actuator rod 78. The outermost end of the arm 86 opposes a stationary gripper finger 90 formed at one adjacent corner of the block member 70.

In operation, when it is desired to downfeed the package tube 11, the solenoid means 76 is energized, drawing the gripper member 86 inwardly toward the stationary gripper finger 90 to pinch the adjacent margin 91 of the package member 11 therebetween. Thereafter, solenoid means 74 is energized, drawing the entire block 70 downwardly against spring 72 to feed the tubular member downwardly in accordance with the down-stroke of the solenoid-actuated link 73. After completion of the down-stroke, the gripper finger solenoid 76 is selectively deenergized, releasing the margin of the tubular package member 11, following which solenoid means 74 is deenergized, permitting return spring 72 to raise the feeder block 70 to its uppermost position illustrated in FIG. 1.

In order to adjust the down-feed stroke of the assembly 19, block member 71 is fitted with an adjustable stop bolt 92 at the innermost end thereof which may be adjustably positioned to engage the head of a second adjustable stop 93 projecting upwardly from arm portion 60 of bracket 61.

As previously mentioned, the package tube 11 having its bottom end 95 sealed and the portion thereof below level 63 filled with liquid, is position with its lower end gauge means 21 which is adjustably mounted on a support means 96. As shown best in FIG. 1, the gauge 21 comprises a lower block portion 97 having a resilient spring finger 98 extending upwardly from one side thereof. Finger 98 is disposed in spaced relation to the support 96 to provide a uniform spacing receptive of the lower end of the package tube 11 and effectively determinative of the desired thickness. Adjustable positioning of the gauge 21 is coordinated with the down-stroke of the feeder assembly 19 so that as successive packages are sealed and cut from the lower end of the package tube 11 by means 20, each down-stroke of the feeder assembly will reposition the lower sealed end of the tube 11 in the gauge means. After the sealing and severing operation by the means 20, the liquid-filled packages held between the gauge 21 and support 96 may be removed by any conventional known means, unnecessary to describe herein.

The heat sealing and cut-off means 20 will be understood best from an inspection of FIGS. 1, 5-8 of the drawings. As particularly shown in FIG. 1, means 20 comprises an actuating solenoid 100 having a core-responsive actuator link 101 supported on an upwardly extending bracket means 102. The lower end of the actuator link 101 is pivotally joined at 103 to one end of a T-shaped rocker arm 104 comprising a bottom cross arm portion 105 and a central stem portion 106. Pivotal connection 103 is at one end of the cross arm 105 while the opposite end thereof is pivotally joined to a pivot block 107 by pin means 108. A spring member 109 is coupled to and extends between the central stem portion 106 and the support bracket 102 to normally bias member 104 in a clockwise sense as viewed in FIG. 1. This action effects the return of member 104 to its upright position as illustrated in that figure upon deenergization of the solenoid means 100. Conversely, energization of the solenoid 100 serves to actuate the coreactuated link 101 upwardly, rocking member 104 counterclockwise about pivot pin 108 for purposes to appear presently.

At the upper end of the stem portion 106 is a transversely related, horizontal knife support arm 110. The right hand outer end of arm 110 (see FIG. 1) is adapted to abut the upper end of bracket 102 to serve as a stop device for limiting clockwise movement of the T-shaped member 104, as urged by spring means 109. Affixed to one upper side of arm 110, as by spot-welds 111 (see FIG. 8), is a generally rectangular shaped sealing plate member 112 having a sealing knife portion 113 extending centrally outward of one front marginal edge 114 thereof (see FIG. 8). The portion 113 is equipped with the usual heater wire 115 adjacent the outer tip end 116 thereof as best shown in FIG. 8.

Mounted on opposite sides of the sealing plate member 112 and intersecting substantially at right angles immediately in front of the outer tip end 116 of portion 113 are a pair of planar wiper blade members 118 and 119, each respectively associated with a pair of support brackets 120, 120 and 121, 121 secured to opposite faces of plate 112 as by rivet means 122. The connection between the wiper blades 118 and 119 and their brackets 120, 121 is by pairs of leaf spring means 125, 125', attached to the blades 118 and 119 and brackets 120, 121 by rivet means 126. It will be noted (FIG. 8) that such springs cross one another on opposite sides of knife portion 113.

It will be recognized from FIG. 1 of the drawings that the wiper blades 118 and 119, with portion 113 disposed therebetween, is located on one side of the package tube 11 directly opposite a stationary knife assembly 130 comprising a bracket 131 affixed to a support, a stationary heater blade 132 having heater wire 133 and a guard member 134 adjacent the blade means 132. Specifically, the guard member 134 and blade 132 are affixed to the support means 131 by mounting bolt 135. In operation, the movable blade 113 affixed to the upper end of the T-shaped member 104 moves toward and away from the stationary blade 132, with the liquid-filled package tube 11 disposed therebetween.

It will be recalled that one of the principal problems confronted in packaging liquids utilizing thermally sealed materials, such as plastic films, occurs when attempting to heat-seal the plastic films around the liquid at temperatures in excess of the normal boiling temperatures of the liquid being encapsulated. It readily will be appreciated that if boiling or gasification of the liquid does occur within the package, there is great risk and danger of violently disrupting the package and this is even more so when, as in the present instance, it is intended to completely fill the package with liquid prior to sealing the same. In packaging liquids according to the present invention, it is preferred that there be no partial gaseous atmosphere within a package of the permeant liquids so that the effective area for permeation of the active liquid ingredients through the walls of the plastic package can be maintained at a predetermined constant. If the liquids should diffuse into a gaseous atmosphere within the package interior, the gaseous materials will permeate through the walls of the package, at a lower rate than the liquid and more importantly will reduce the area in contact with the liquid permeant. Consequently, if one is to maintain a rate of permeation at a known constant, it is essential that either all liquid state or gaseous state permeation take place, but not a combination of both.

In order to hermetically seal a completely liquid-filled plastic package utilizing heat sealing principles, particularly when packaging the more volatile materials, the present invention presents a unique method and means for effectively isolating the liquid contents of the package from the zone of thermal sealing. To this end, particular reference is now made to FIGS. 1, 5, 6 and 7 of the drawings.

As illustrated in these figures, the operational sequence for effecting the desired heat sealing of the top margin of a packaged product filled with liquid is set forth. As initially illustrated in FIG. 1 of the drawings, the liquid-filled tube 11 is in position ready for producing a thermal weld or seal across the top end of the selected bottom portion thereof to produce a liquid-filled packaged product 135 (see FIGS. 7 and 9). This sealing operation is brought about by the means 20, the elements of which have been described hereinabove.

As shown in FIG. 5, energization of the solenoid means 100 serves to advance the sealing member 113 toward the liquid-filled package tube 11. Prior to engagement of the member 113 with the wall 14' of the tube 11, however, the wiper blades 118 and 119 engage such wall well in advance of the sealing tip end and serve to pinch wall 14' tightly against the opposing wall or film layer 14 and the secondary heater blade 132. As with the sealing blades 38 and 40 of assembly 15, the movable sealing member 113 is generally at an elevated temperature over that of the stationary blade 132 which for convenience sake herein may be termed "hot" and "cold" blades, respectively. Be that as it may, as shown in FIG. 5, initial contact and movement of the wiper blades 118 and 119 against the package tube 11 effectively pinches off the package tube between the two opposing blades 113 and 132. Continued advancement of the hot blade 113 toward the cold knife blade 132 causes the wiper blades 118 and 119 to move laterally away from one another bowing the springs 125, 125', as illustrated in FIG. 6, and thereby maintaining resilient pressure contact with the plastic layer wall 14' of the tube. This effectively wipes the liquid upwardly and downwardly away from the zone of thermal sealing designated 136 in FIG. 6. In this state, the two layers 14 and 14' of the plastic tube are pressed firmly together and stretched across the cold blade 132, with back-up support therefor being provided by the adjacent platen ends of the support bracket 131 and the shield member 134 associated with and located laterally adjacent the cold blade 132. Continued advancing movement of the hot blade 132 brings the same into contact with the plastic walls of the tube member 11 to produce a thermal weld barrier laterally thereacross. At eventual contact of blade 113 with the cold blade 132, the tube 11 is severed and the bottom portion or tubular package 135, filled with liquid, is effectively separated therefrom.

Deenergization of solenoid means 100 causes returning movement of the hot blade 113 toward the right as viewed in FIG. 7 along with returning movement of the wiper blades 118 and 119. This frees the packaged product 135 for removal from the lower end of the tube member 11.

After the severing of the package 135 as hereinabove described, feeder assembly 19 releases the tube 11 and then is actuated to downfeed the tube 11 into the gauge means 21 thereby pulling the tube material through the lateral margin sealing and trimming assembly 15. Inasmuch as the liquid level within tube 11 lowers with the downfeeding thereof, the liquid level control assembly 18 will sense, as heretofore explained, the absence of fluid within tube 11 opposite the photocell 56. Consequently, appropriate circuitry is energized to signal for the inflow of liquid via the filler tube 13. Sufficient liquid is then added to the tube 11 to bring its level up to the desired static head control level 63 as previously explained.

From the foregoing description of the apparatus illustrated in FIGS. 1 through 8 of the drawings and its operation, it will be readily understood that the fundamental operating steps for the improved procedure for packaging liquids according to this invention has been fully set forth, along with a preferred means for accomplishing the same. Nevertheless, it is to be recognized that exact means of the apparatus described is not essential to the accomplishment of the disclosed method and it is fully contemplated that various changes, modifications and substitutions can be made therein by those familiar with the art without departing from the teachings of this invention. For example, instead of two separate tapes for the formation of the tube package 11, the same may be produced from a single tape, folded over into a double layer and then marginally sealed along one lateral edge. Additionally, the particular liquid supply system described is not necessarily essential to the accomplishment of the described method inasmuch as liquid may be supplied by any number of known systems, including pressurized control systems, gravity feed systems, pumps and so forth. Further, while the disclosed apparatus has basically been described as being actuated by solenoid means, the functions thereof may be accomplished by utilizing hydraulic, pneumatic, mechanical or other systems well within the skill of the art. Of like import is the removal of the packaged items from the forming equipment which may be done manually or by any number of known pick-off systems. Additionally, it is fully contemplated that the described photocell system for regulating the level of liquid within the tube 11 may be replaced by a variety of other devices including pressure-sensitive switch means located to sense the static head of the liquid in tube 11.

With respect to the packaged product 135 as herein described, it is not essential that the same be severed from the tube member 11 during the sealing operation of the means 20. To the contrary, it is fully contemplated that it may, in certain instances, be desirable to present an elongated product in which individual packets of liquid are separated by intervening thermal-weld seals, but not individually severed as hereinabove set forth. It is also fully contemplated that different package configurations and size may be employed, including the provision of hanging tabs at one end of the sealed packets.

It also is to be noted, as best shown in FIG. 9, that the interior surfaces of the plastic layers 14 and 14', for the package 135 are preferably scored with a series of fine line scratches to provide a uniform capillary distribution system over the interior walls of the package. This feature is of particular importance in distributing the liquid permeants evenly over the interior of the package walls, especially when the package is in a near collapsed state. That is to say, as liquid permeates through the package walls, the volume of liquid therein diminishes and the package walls gradually collapse inwardly under atmospheric pressure. When the liquid content is nearly exhausted, the capillary feed system takes over to evenly distribute the liquid over the entire interior surface area of the walls until all permeant has escaped. In this manner, the effective area for permeation distribution of liquid through the package walls is maintained substantially uniform throughout the package life. Without such a capillary distribution system or its equivalent, as the package walls collapse toward one another, areas appear where the opposing walls contact one another without any liquid therebetween. Such contacting areas are then ineffective to the distribution of permeant through the package walls. For similar reasons, bubbles of air or gases in the package are to be avoided, since such act to keep the walls separated and effectively prevent distribution of liquid over the interior wall surfaces.

Claims

I claim:

1. Apparatus for hermetically sealing, between opposing walls of a thermoplastic package, a gas-free body of liquid which is vaporizable at atmospheric conditions, said apparatus comprising means for forming a vertically elongated tubular package blank sealed along the bottom and lateral margins thereof, means for filling said blank with the liquid being packaged, means for controlling said filling means to maintain a predetermined head of liquid in said blank to control package size, means for heat-sealing said blank within an area spaced from the bottom margin of said blank and located in a part of said blank filled with liquid, means for severing said blank within said area, and means for avoiding vaporization of the liquid during heat-sealing by displacing the liquid in said blank from said area prior to heat-sealing and for maintaining the liquid in spaced relation from said area during heat-sealing, said means for avoiding liquid vaporization comprising means for engaging the opposed surfaces of the walls over a selected region which include said area and which extends above and below said area, and means for actuating said wall engaging means to press together opposing interior surfaces of said walls in said selected region with sufficient pressure so as to eliminate liquid therebetween, and to maintain together the interior surfaces of said walls in said selected region during heat-sealing so as to retain the liquid being packaged in spaced relation to said area.

2. The apparatus of claim 1 wherein said wall engaging means comprises a pair of wiper blade means engageable with one of said walls, platen means opposite said blade means engageable with the opposing wall, and means for moving said blade means apart in the direction of the length of said package blank while maintaining said walls pressed against said platen means thereby to wipe the liquid from the interior surfaces of said walls.

3. Apparatus according to claim 1 and further including gauge means for regulating the volume of liquid within the lower end of said blank between said bottom margin and said region.