Method of making sealed packages

May 30, 1939.

D. E. MAXFIELD

2,160,367

METHOD OF MAKING SEALED PACKAGES

Sheets-Sheet 1

Filed Nov. 27, 1937

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May 30, 1939. d. e. maxfield 2,160,367

METHOD OF MAKING SEALED PACKAGES Filed Nov. 27, 1937 2 Sheets-Sheet 2

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A i

Patented May 30, 1939

2,160,367

UNITED STATES PATENT OFFICE

2,160,367

METHOD OF MAKING SEALED PACKAGES

Daniel E. Maxfield, Philadelphia, Pa., assignor to Stokes and Smith Company, Summerdale, Pa., a corporation of Pennsylvania

Application November 27, 1937, Serial No. 176,815

Claims.

My invention relates to methods of making, filling and sealing containers to form sealed packages, and particularly to methods of making, filling and sealing non-rigid containers for vari⁰ ous solid materials.

In accordance with my invention, during formation and/or filling of a container and before its final closure, and preferably before and/or ₁₀ during the filling operation, there is introduced into the container a conditioning agent, specifically a desired gas, vapor, or mixture of gases, or vapors, for beneficially affecting or preserving the package contents, the agent remaining in the package after it is sealed.

More specifically, after formation of a tub» from a web of “Cellophane”, or other suitable flexible material, and closure of the tube at one end to form a receptacle open at its other end, ₂₀ a desired gas, vapor, or mixture of gases or vapors, is caused to flow into the receptacle partially or completely to displace the air therein; preferably, the flow is continued until the receptacle is sealed, as by flattening the walls of the tube, above its contents, into adhesive relation 25 with each other.

Further in accordance with my invention, there additionally may be introduced with the filling material, a gas or vapor, or mixture of them, of composition the same as, or different from, that 30 previously introduced as aforesaid into the receptacle during its formation, which additional gas or vapor itself, or with the previously introduced gas or vapor, comprises or constitutes the conditioning agent.

My invention further resides in methods having the features hereinafter described and claimed.

For an understanding of my invention, reference is to be had to the accompanying drawings ⁴⁰ in which:

Fig. 1; in perspective, illustrates formation of a tube from a web of flexible material:

Fig. 2, in perspective, illustrates closure of one ₄₅ end of the tube of Fig. 1 and in addition of filling material and a conditioning agent;

Fig. 3, in perspective, illustrates the completed, sealed package, before its severance from the web or strip;

Mg. 4 diagrammatically illustrates elements of a machine for performing the methods of Mgs.

to 3 and several packages at successive stages of their completion;

Mg. 5 is a plan view in section taken on line 55 5—5 of Mg. 4;

Mg. 6 is a front elevational view, partly in section, of a modified form of filling tube;

Mg. 7 illustrates the method as applied to formation of square bags and significant parts of 60 a mechanism for performing it;

(Cl. 93—3)

Fig. 8 is a plan view in section, taken on line 8—8 of Mg. 7;

Mgs. 9 and 10 illustrate another mode of making, filling and sealing a container using two webs of flexible material; 5

Fig. 11, in perspective, illustrates a third continuous method of making, filling and sealing containers;

Fig. 12, in perspective, shows the product resulting from the method of Mg. 11. ¹⁰

In the packaging of materials such as food products, medicinal powders or tablets, tobacco, and other materials, it is frequently desirable to preserve or modify their characteristics during the period elapsing before they are opened for use ¹⁵or consumption of their contents. In some cases, t he nature of the contents of the package may be such the air in the package should be very dry, or again, of moisture content approaching saturation, or, in other cases, the atmosphere may 20 preferably comprise or consist of some gas, such as nitrogen or carbon dioxide.

Although not in all aspects unsuited for use in connection with rigid packages, such as those of tin, glass, pitch-board, fiber or the like, my ₂₅invention is especially suited for non-rigid sealed packages, particularly those made of flexible materials such as “Cellophane”, paper, or the like.

Referring to Fig. 1, a web or strip W of bag material fed, for example, from a roll A is formed ₃₀into a tube T and the edges of the strip forming the seam of the tube joined in any suitable manner; for example, the edges of the strip may be overlapped to suitable extent to form a seam S which is made gas-tight in any desired or suit- ₃₅able manner. When the strip is of heat sealing “Cellophane”, the sealing may be accomplished by applying heat and pressure, as by a corrugated, heated roll, along the overlapping edges of the strip.

The tube so formed is flattened, as at E, to provide a receptacle R closed at its lower end and open at its upper end; the flattened portion E may be sealed in any suitable manner; for example, when the strip S is of moisture-proof heat 43 sealing “Cellophane”, or of “Sylphrap”, “Maralux” or like papers having a coating of, or impregnated with, a substance which softens upon application of heat, the sealing may be accomplished concurrently with the flattening of the 50 strip by heated, clamping tools, preferably corrugated.

The contents of the package, such as candies, potato chips, soap flakes, or the like, is introduced into the tube or open end of the recep- 55 taele, which is thereafter closed and sealed, in any suitable manner, and particularly as hereinafter described. After formation of the seam S and closure E, and before, or during, addition to the receptacle R of the package contents or go

2,160,367 filling material F, the desired or selected conditioning agent is introduced into the receptacle, as through the tube I. When the conditioning agent is gaseous, such as dry or moist steam, car5 bon dioxide, nitrogen or the like, the addition of the conditioning agent may be for a predetermined time, by a predetermined amount, or may be continuous throughout the formation, filling and closing of the package.

The gas or vapor, or mixture of them, introduced into the open-ended receptacle or bag more or less completely displaces the air therefrom and maintains its distended form to receive its intended solid contents, whether they be in the 15 form of powders, flakes, tablets, or any other shape or form.

After or during introduction of the conditioning gas, the strip W, or tube T, is fed to bring the solid contents suitably below the lower end 20 of the tube I, whereupon the tube T is again flattened, as In Fig. 3, to form the second seal E for the upper end of the package or receptacle R. The completed package containing the filling material F and the conditioning gas is then severed 25 from the strip. For continuous flow of the conditioning agent through the pipe I, the clamping of the tube to form the upper seal E serves as an automatic cut-off preventing further addition of gas to the receptacle or escape of gas 30 when the strip is severed as hereinafter described.

The clamping of the tube as foresaid to provide the top seal for package R concurrently forms the bottom closure for the next receptacle 35 R&lt; which, for continuous flow of gas through pipe I, immediately begins to receive conditioning agent before or during addition of the filling material.

As thus far described, the packages are in a 40 continuous string attached to each other by the flattened portions E of the strip or web; to form individual packages, each of the seals E is cut crosswise, as in Fig. 4, by a knife 14 or the like.

Although not limited to any particular mech45 anism, my method may be conveniently performed by suitable modification of known types of package-forming and filling machines, for example, a machine of the type illustrated and described in Zwoyer Patent #1,986,422 or of the 50 type shown in Aldrich Patent #1,937,501.

Referring to Fig. 4, the web W is threaded over the shoulder plates 2, 2, and thence downwardly between the outer former-tube 3 and inner former-tube or mandrel 4. The edges of the 55 strip are led downwardly and across, one inside the other, to form a seam; the left-hand edge of the strip is led to the right by the guide piece 5, while the right-hand edge of the strip is led to the left by the guide piece 6. Thus there is GO formed on the outside of the inner former-tube 4, a tube T of flexible bag material with a longitudinal seam comprised of the overlapping edges of the web or strip. A heated corrugated roll presses the overlapping edges of the web against 05 tube 4 to form the seal S. The flexible tube T is flattened, beyond the former-tube 4, to form the seal E by the heated clamping tools 7 which move from the dotted to the solid line positions indi. cated in Fig. 4, to draw further web material from 70 the roll A for shaping into tubular form as above described. The flattening of the tube T at E forms a receptacle whose lower end is closed and whose upper end surrounds the former-tube 4.

The contents of the bag are fed thereinto, by 75 gravity or some positive feeding means, through the passage or tube 8 disposed within the inner former-tube 4. The amount of material fed for each movement of the. clamping tools 7 from and back to its dotted line position may be regulated in any desired way, for example, by a cut-off 5 valve in a hopper or conduit forming a continuation of tube 8, or by any other of the known expedients used in filling machines.

As appears in Figs. 4 and 5, the space between the filling tube 8 and the inner former-tube 4 jo is divided, as by partitions 9, 9, into two chambers 10, 12, which extend lengthwise of the filling tube 9 and which are out of communication with each other except at their lower ends. At its upper end the chamber 10 is in communication 15 with a pipe or conduit 11 extending to the source of conditioning gas or vapor. In the communication line between the gas source and chamber 10 there may be interposed any suitable valve mechanism for controlling the pressure or rate 20 of flow of gas and/or suitable valve mechanism operated manually, or automatically»· in timed relation to the formation, filling and closing of packages on and below the tube-forming mandrels 3 and 4. 25

The upper end of chamber 12 is in communication with a pipe or conduit 13 which may discharge to waste or to reclamation apparatus.

In the absence of control valves in the supply line 11, gas flows continuously from the source 30 through chamber 10 into the closed tube or partially formed package extending from the former-tube 4 to the clamping tools 7, and thence upwardly through chamber 12 and out of the discharge pipe 13 which is preferably provided with 35 a check-valve not shown.

The flow of gas or vapor replaces the air within the receptacle including any air which may have been entrained by the filling material during its movement from a hopper or other source of sup- 40 ply downwardly through tube 8. Preferably the flow of conditioning gas continues, insofar as any particular receptacle is concerned, until after it has been filled and the clamping tools have flattened the tube T above the contents or filling 45 material to complete the sealing of that receptacle. My invention is not limited, however, to such continuous flow of conditioning agent, for a valve in the gas-supply line may be timed to provide for introduction of a predetermined 50 amount of conditioning agent into each package.

After each package has been filled and sealed, it is severed from the continuous strip as by a knife 14, Fig. 4, which cuts midway of the flattended portion E between two successive pack- 55 ages. If desirable or necessary, a suitable strip of metal or foil may be applied to embrace the ends of the packages to add strength to the seal. ' For most applications this is not necessary, particularly when the strip is moisture-proof, heat- 60 sealing “Cellophane”, since the heat and pressure applied to the ends and seam form a joint which remains gas-tight for all ordinary handling.

When the material is not free-flowing and tends to jam in the tube 8, there may be pro- 65 vided a feed auger 15, Fig. 6, extending lengthwise and interiorly nf the tube 8. Such an auger also may be utilized to provide for feed of a predetermined amount of material to each receptacle in turn; in such case, the auger 15 is intermittently 70 actuated to rotate a predetermined angular extent between successive strip-feeding movements of the clamping tools 7.

When it Is desired to make bags of the square type, the shape of the inner former-tube is cor- 75

2,160,367 respondingly modified, as shown in Figs. 7 and 8. The upper cylindrical portion of the formertube gradually merges into a portion 4A of rectangular cross-section and accordingly the 5 tube T of bag material is caused to assume a similar shape. .The inner former-tube and the filling tube 8 may be, as suggested in Fig. 8, a single piece or may be fabricated; specifically, as shown in Fig. 8, the gas inlet duct 10 and gas 10 outlet duct 12 are formed in the walls of a member 4A whose hollow center provides for flow of the filling material to the receptacles, and whose outer perimeter corresponds in shape to the receptacles to be formed. In the particular ex15 ample shown, the interior configuration of the passage for filling material is suited for crackers or wafers C.

In similar manner, a conditioning agent may be introduced into packages, formed from two 20 webs of flexible material, during their formation, before and/or during filling thereof, and before their severance from the two webs after sealing. Referring to Fig. 9, the two webs Wl, W2, of any of the flexible materials herein contemplated, are 25 drawn from rolls Al, A2 and shaped, as about former-tube 4, into a tube T2. Each of the webs is of a width somewhat greater than half the circumference of tube 4 to provide margins or flanges eventually to be joined, as by applica30 tion of heat and pressure to form the seams SI, S2 extending from tube T2, Fig. 10. As in the preceding methods, the tube T2 is flattened below the lower end of the former-tube 4 to provide an end seal E for the lower end of a bag or re35 ceptacle R8 whose upper end at that time snugly fits the former-tube 4. Before and/or during the filling of the bag with candies, powders, or the like, which are introduced into it through the filling conduit 8, a conditioning gas is permitted 40 or caused to flow into the bag from duct 10, the excess flowing out of the bag through duct 12. The tube of web material is then flattened and sealed above the filling material to form a closed package R7, which is subsequently severed from ₄₅ the web, as indicated in Figs. 9 and 10, and so then becomes a separate individual package R6.

In the method illustrated in Fig. 11, the edges of a single web W3 of package material, instead of being overlapped as in Fig. 1, are brought into _so face to face engagement to form a seal S3 extending outwardly from the former-tube 4. As in the prior methods described, during the formation of a package, a conditioning gas is introduced thereinto, preferably before or during fill55 ing of the bag, when in the position of bag RII. After the bag is sealed above the contents, as indicated by bag RIO, it is detached from the web by cutting of seal E transversely of the web to form the completed package R9 containing solid CO contents and a conditioning agent therefor.

Though in the methods specifically described, I prefer to use, because of simplicity of seal-formation, web material coated or impregnated with a bonding substance which becomes plastic or ad,.5 hesive upon application of heat, my invention comprehends use of other types of adhesives; for example, unset glue may be applied to those surfaces of the web or webs which subsequently are to be joined to form the various seals of each ₇₀ package.

It is sometimes desirable, in any of the methods described herein, to provide for introduction with the filling material of a conditioning gas or vapor which may be the same as or different from that introduced through pipe I of Fig. 2 or duct 11 of Figs. 4, 6, 7, 9 or 11. This is readily accomplished when the gas is heavier than air by utilizing, for the solid material to be packaged, a hop- 5 per of considerable depth. When heavy gas, for example, carbon dioxide, is supplied to the hopper, it sinks toward the bottom thereof to displace air which otherwise would pass with the material to the bags during the filling operation. 10 The downward movement of tube Tor Tl by the clamping tools affords a pumping action which may be utilized to draw the heavy gas from the hopper through conduit 8 into the receptacles as they are successively formed.