US2708541A - Sealed package evacuating means - Google Patents

Description

y 1955 w. c. JONES 2,708,541

SEALED PACKAGE EVACUATING MEANS Filed Oct. 10, 1952 2 Sheets-Sheet l IN V EN TOR. Wi/[iam 6. Jan 66 A TTORNE Y5 May 17, 1955 w. c. JONES SEALED PACKAGE EVACUATING MEANS 2 Sheets-Sheet 2' Filed Oct. 10, 1952 INVENTOR. W/Y/l'G/f? C. Jones NEKS outer wrap can be pressed together.

United States Patent SEALED PACKAGE EVACUATING MEANS William C. Jones, Midland, Mich assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Application October 10, 1952, Serial No. 314,043

4 Claims. (Cl. 226-56) This invention relates to a machine for evacuating previously sealed packages having a flexible wrap of which at least the inner surface is heat-scalable. It relates in particular to a machine for evacuating packages of the merchandise enclosed between two flexible sheets which have been sealed together about their peripheries.

Many food products and other commodities are now packaged in flexible sheet material made in whole or in part of moisture-impervious plastics. Some of the products so-packaged are adversely affected by prolonged exposure to air, but retain their desired characteristics if kept in an atmosphere relatively free from oxygen. Thus, some materials remain fresh in vacuo, others are favored by the presence of a gas such as nitrogen, or carbon dioxide, or ethylene oxide, and some products, such as pickles and olives, are preserved in vinegar, brines, or other liquids. The attainment of the desired atmosphere in flexible packages has constituted a problem which has heretofore been solved only with difliculty. The usual approach has been to seal three sides of the flexible container, before or after putting the merchandise in place, and to evacuate the package from the open fourth side, and finally sealing that fourth side, suitably after restoration of atmospheric pressure either with an inert gas or with a preservative liquid. Theapparatus required for effective operation of such a process is both cumbersome and expensive. It would be preferable to be able to evacuate packages whose outer wrap is a flexible and heat-scalable plastic material after the four sides of the package have been sealed with the merchandise in place. The provision of a simple apparatus to effect that result is the principal object of this invention.

The machine of the invention accomplishes the desired result, provided the sealed package to be evacuated presents a small area, within the sealed boundaries of the package, in which two of the flexible sides of the scalable The new machine operates by punching a hole through that area of the opposed sheets; the so-perforated opposed sheets are separated by externally applied suction; the package is evacuated by suction applied through the perforations; inert material is fed into the package through the same perforations, if desired; the opposed sheets are pressed together with their perforations in register; and, the

plastic sheet is sealed around the perforations.

The operation of the machine will be more apparent by reference to the accompanying illustrations and the following description which represent a preferred form of the machine. In the annexed drawings,

Fig. l is a vertical mid-section through the machine;

Fig. 2 is a cross section along line 2--2 of Fig. 1;

Fig. 3 is a cross section at the line 33 of Fig. 1;

Fig. 4 is a vertical mid-section of the chief cylindrical member of the lower portion of the machine; and

Fig. 5 is the completed package.

The machine of this invention as shown in Fig. 1 consists of two sections (hereinafter called the upper made of a heat insulating material.

2,708,541 Patented Mayv 17, 1955 and lower sections, respectively) usually mounted vertically within a press or other device by means of which the sections may be caused to move toward or away from each other, into and out of co-acting pressure relationship. Thus, it may be seen that both sections may be movable or one section movable with the other section held stationary to a supporting framework.

In a preferred embodiment as shown in the drawings, the lower section is attached to a supporting framework 10 of convenient height by means of a base piece 11 which is held firmly in place by bolts 12. A hole 13 is centered in the base piece 11 and extends through framework 10 through which, as later described, other parts of the machine project. Fastened to the base piece 11 by cap screws 15 is an inverted straight-cup shaped bracket 14 (hereinafter called the bracket). In the side wall of bracket 14 is bored a circular aperture 16 through which vacuum or gas lines may pass to be connected to inner parts of the machine. Bracket 14 supports a ring 17 of a heat insulating material, fastened to bracket 14 with cap screws 18. The inside circumference of ring 17 is recessed from above. Fitted into the recess 19 so-formed in ring 17 is another ring 20 of heat conducting material having an inside diameter equal to the smaller inside diameter of ring 17 and with its upper edge extending above the upper surface of ring 17. Ring 20 is connected by means of suitable leads (not shown) to an electrical source capable of raising the temperature of ring 20 above the fusion temperature of heat scalable material.

Resting on base piece 11 and inside of bracket 14 is a hollow cylindrical rubber spring or other cylindrically bored yieldable cushion 21 with an inside diameter at least as large as the diameter of hole 13 in base piece 11. The rubber spring 21 may be replaced by other forms of elastic devices such as volute or spiral springs. Resting on spring 21 is a horizontally flanged vertical cylinder 22 whose stem extends through spring 21, hole 13 in base piece 11, and framework 10. The flange of cylinder 22 is of such diameter as to be able to move up and down freely inside the vertical walls of bracket 14. Preferably a hole 23 is bored through the stem and flange of cylinder 22. Fastened by cap screws 24 to the upper flange of cylinder 22 is a cylindrical member 25 embodiment, a hole 26 of the same diameter as the bore 23 in flanged cylinder 22 is bored longitudinally through cylindrical member 25 and communicates with bore 23.

The upper part of hole 26 is counterbored to a larger, inside diameter forming a notch 27. Fitted into notch 27 is a cylindrical rim 28. Rim 28 is made of a material,

suitable for maintaining a sharp edge useful for repeated cutting of the flexible wrapping materials. In other forms of the machine, bore 26 extends vertically downward only as far as the lower edge of rim 28, terminating above the flange of member 22. Also bored longitudinally in cylindrical member 25 are several equally spaced vertical holes 29 arranged in a circle, radially outward from hole 26. Bored laterally near the lower end of cylindrical member 25 is a hole 30 tapped at its ,outer end to receive a standard pipe connection andto which vacuum or gas lines may be attached through aperture 16 in bracket 14 to external sources. Connecting lateral bore 30 with holes 29 is a channel 31 drilled vertically into the lower end of cylindrical member 25 and of a width equal to the diameter of holes 29 and of a depth sufficient to include lateral bore 30. Thus, when cylindrical member 25 is affixed to flanged cylinder .22 with.

In the preferred by means of upwardly projecting coaxial shank 32. The press is capable of exerting a pressure great enough to cause the rubber spring 21 to yield. Projection 32 is integral with a larger cylindrical head piece 33 from which depends a smaller coaxial tube 34. Tube 34 has an external diameter of a size to give a close sliding fit with hole 26 in cylindrical rim 28. The lower outside edge of tube 34 is sharp, and in conjunction with inside upper edge of cylindrical rim 2S acts as a cutter for the packaging material. The bore 35 of tube 34 extends upward into header 33 and communicates with a lateral bore 36 in header 33. The outer end of lateral bore 36 is tapped to receive a standard pipe thread. Drilled radially outward from bore 35 near the lower end of tube 34 is a small hole 37. A hole 38 is also drilled radially into header 33 to communicate with a cylindrical channel 39 which is drilled vertically upward from the lower surface of header 33 and has a radius larger than tube 34. The outer end of lateral hole 38 is tapped to receive a standard pipe connection. The dependent tube 34 and the lower face of header 33 are fitted with a flanged cylinder 40 which is fastened to header 33 with cap screws 41, and is made of an insulating material. Drilled longitudinally through flanged cylinder 40 are several equally spaced holes 42 arranged in a circle of such size as to communicate with channel 39. Thus, a tunnel is formed connecting holes 42 with lateral hole 38 through which suction may be applied. The lower cylindrical projection of insulator 40 is of the same diameter as the upper part of cylindrical member 25.

Fitted around this projection of insulator 40 is a ring 43 of heat or electrically conducting material of such length that its lower surface is flush with the lower surface of the projection of insulator 40. This ring 43 together with ring 20 of the lower section of the machine are electrically heated or are the electrodes of a radio frequency generator and as such act as a sealing device for the plastic portion of the packaging material.

The machine of this invention is designed to function after merchandise has been inserted between sheets of a heat scalable, flexible material and all edges 45 sealed by any suitable means. The merchandise in the bag 44 thus formed must be loose enough so that a corner of the bag 44 at least as large as the sealing rings 20 and 43 may be inserted into the machine. the sealed bag 44 is placed between the upper and lower sections of the machine and the two sections of the machine are caused to move together until insulator 40 and cylindrical member 25 are in close contact with the film. In so doing, a hole 46 is cut in the bag 44 by the edge of rim 28 and tube 34. The small piece of film cut out is transmitted through either hole 25 or 36 to a vacuum pump and out the exhaust of the pump. A vacuum is then drawn on ports 30 and 38 by means of vacuum lines attached to the threaded portions of ports 30 and 38 at one end and to suitable vacuum drawing means at the other end. Suction is transmitted through channels 31 and 39 to holes 29 and 42 and thence to the outer sides of the bag 44, holding the package walls firmly against the upper and lower sections of the machine. The two sections of the machine are then caused to move apart until vacuum port 37 and tube 34 is above the surface of rim 28 and thus between the layers of material forming the walls of the bag 44. A reduced pressure is then created through ports 23 and 36 by means of an external vacuum pump, and is then trans mitted through holes 26 and 35 to port 37 and thence to the interior of the bag 44. However, it should be realized that when hole 26 does not extend completely through cylindrical member 25, suction is applied only through port 36 and hole 35 to port 37. After evacuating the interior of the bag and with the vacuum being maintained, the sections of the machine are caused to move together with suflicient pressure to cause the rubber cushion 21 to yield, depressing the cylindrical This corner of 1 member 25 until the film is contacting sealing rings 20 and 43. The radio frequency generator or electrical heating apparatus is activated causing rings 20 and 43 to heat or to transmit radio frequency waves sufficiently to form a continuous seal 47 around the hole 46 previously punched in the corner of the bag 44. The vacuum at ports 30 and 38 is then released and the upper and lower sections of the machine are separated, leaving the evacuated and sealed bag 44 free to be removed from the machine.

The machine may be modified to provide for the displacement of the original air, after evacuation, with an inert gas or other fluid, by replacing the vacuum lines connected to ports 23 and 36 with three way valves. One outlet of each valve may be connected to ports 23 and 36, one inlet of each valve to the vacuum system, and the remaining inlet of each valve attached to a supply of inert fluid. The gas or other fluid supply may be provided with a suitable regulating device to prevent the fluid from exceeding the bursting strength of the bag 44.

In operation, the vacuum is created as before at which time the three way valve is turned so as to close ofl the vacuum and to admit inert fluid. The machine is then closed and the seal made as before.

The flexible packaging material employed in the package to be sealed must have at least its inwardly directed surface heat scalable. Thus, either unsupported films of plastic or paper or cellophane coated with a heat sealable coating will work in the present machine. The original package need not have been heat sealed, however, as it may have been closed by an adhesive or by any other suitable means by which an airtight seal may be made. The flexible wrapper of the package may be held more positively to the sections of the machine if holes 29 and 42 are connected by a concave channel 48 (Fig. 4) of a diameter equal to channel 30.

It is possible to make the machine semi-automatic by employing a timer controller to sequentially lower the upper section to cut a hole in the package, cause a vacuum at ports 29 and 42 to hold the sides of the package to the upper and lower sections; raise the upper section to sep-' arate the sides of the package, cause a vacuum in the interior of the package, lower the upper section with sufficient pressure to depress the movable parts of the lower section to expose the sealing rings in the lower section, start and maintain electrical flow until the scalable material has fused, and raised the upper section so that the completed package may be removed from the machine.

I claim:

1. A machine for evacuating a sealed package formed from a flexible material, the interior surfaces of which are capable of being heat sealed, and for rescaling the package, said machine having two separately controlled sections in cooperative alignment, each with a working face directed toward the other; a framework supporting the one section; a reciprocating press holding the other section; the first section comprising: a bracket rigidly secured to the supporting framework; a sealing ring mounted in the working face of the said first section; a yieldable cushion within the bracket; movable parts within the bracket, supported on the yieldable cushion means, one surface of said movable parts extending longitudinally through and beyond the exposed surface of said sealing ring, and capable of being depressed below said exposed surface of the sealing ring; a coaxial bore through the said movable parts; a hollow cylindrical metal member with an outer shearing edge in said bore at the plane of the working face of said first section; controllable external means for applying suction through said bore; symmetrically disposed channels arranged externally about and parallel to said bore and communicating with a lateral bore in said movable parts to provide another suction path; an aperture in the fixed bracket aligned with the last said lateral bore in the movable parts; and external and controllable means for applying suction through the said lateral bore and communicating suction channels; said other section of the machine having: a coaxial tubular projection dependent therefrom, aligned with and of a size to fit closely and slidably in the metallic shearing tube in the bore of the first section; a header above said dependent tubular projection; a radial bore near the tip of the tubular projection below said header; a lateral bore in said header communicating with the bore of said dependent tube; means for connecting said lateral bore with the same suction means as the central bore of movable parts of first section; a coaxial channel in said header arranged concentrically about the extension into the header of the bore in the dependent tube and communicating with a second lateral bore in said header; means for connecting the last said lateral bore with the same suction means as the lateral bore of the movable parts of the first section; a sealing ring on the working face of the said section, of a size to mate with the sealing ring in the first section externally of said coaxial channel; insulating means between each sealing ring and other metal parts of their respecting sections of the machine; electrical means connected with said rings to heat interposed plastic packaging material to a sealing temperature; and means for bringing said second section into and out of pressure relation with said first section and intervening sealable packaging material.

2. A machine as claimed in claim 1, in which the sealing rings are electrodes of a radio frequency field.

3. A machine as claimed in claim 1, in which the yieldable cushion is a centrally bored rubber cylinder.

4. A machine as claimed in claim 1, in which a concave circular channel is machined in the upper surface of the movable parts of the first section and in the lower surface of the header of the second section, said concave channels communicating with and forming parts of the outer suction paths in each section of the machine.

References Cited in the file of this patent UNITED STATES PATENTS 1,995,259 Becker Mar. 19, 1935 2,292,295 Royal Aug. 4, 1942 2,387,812 Sonneborn et a1. Oct. 30, 1945 2,506,769 Bergstein May 9, 1950

Images