Processes for vacuum-sealing packaged products, and vacuum-sealed packaged product

Abstract

 A process for vacumm-sealing a product packaged in a container (1) to be evacuated and sealed, which comprises (a) engaging an evacuation sleeve extending from the container with an evacuation nozzle (5) connected to an evacuation pump, (b) evacuating the container via the sleeve and nozzle, and (c) selaing the sleeve, where the evacuation sleeve of which the interior communicates with the interior of the container is a double sleeve extending outwardly from the container, and comprising an inner sleeve (3) engaging within the evacuation nozzle and an outer sleeve (4) disposed around and outside the evacuation nozzle to hold open the inner sleeve during step (b), and wherein at least the inner sleeve collapses under atmospheric pressure only upon withdrawal of the nozzle, and the evacuation sleeve is then sealed at a distance from its place of connection with the container.

Description

[0001] This invention relates to vacuum-packaging and to vacuum-packaged goods.

[0002] The problems sought to be solved by different packaging methods are highly various and depend on the type and quantity of goods to be packaged. One problem, particularly in connection with compressible materials, is to reduce their bulk in a convenient way for transport without spoiling them. Another problem, particularly in connection with granular or particulate materials, is to provide sufficient strength in the packaged product.

[0003] It has been proposed to vacuum-pack flowable or granular products such as cocoa beans (F. Challot and F.-C. Vincent; "Cafe, Cacao, The", (organ of Institut Français du Cafe, du Cacao et autre Plantes Stimulantes), vol. XXI(2) Apl.-June 1977, pp.129-136).

[0004] However, there can be certain disadvantages associated with the measures previously proposed, on account of the complexity, size and cost of the apparatus need to carry them out.

[0005] According to this invention there is provided a vacuum-pack comprising an airtight container such as a bag and a sealed evacuation sleeve extending outwardly from the container. Such an airtight bag, e.g. containing a product to be vacuum-sealed, and having an open-ended sealable double sleeve extending outwardly therefrom, can easily be evacuated and sealed according to the invention, by inserting the inner sleeve into a suction tube, ., evacuating, and sealing the sleeve after withdrawal of all or part of the contained air.

[0006] Accordingly the invention provides a vacuum-sealed packaged product contained in a sealed container which has a double evacuation sleeve of which the interior communicates with the interior of the container, the sleeve extending outwardly from the container.and comprising an inner sleeve and an outer sleeve, and sealed at a location spaced away from the place of connection of the sleeve and the container. Also provided is a process for vacuum-sealing a product packaged in a container to be evacuated and sealed, which comprises (a) engaging an evacuation sleeve extending from the container with an evacuation nozzle connected to an evacuation pump, (b) evacuating the container via the sleeve and nozzle, and (c) sealing the sleeve, wherein the evacuation sleeve of which the interior communicates with the interior of the container is a double sleeve extending outwardly from the container, and comprising an inner sleeve engaging within the evacuation nozzle and an outer sleeve disposed around and outside the evacuation nozzle to hold open the inner sleeve during step (b), and wherein at least the inner sleeve collapses under atmospheric pressure only upon withdrawal of the nozzle, and the evacuation sleeve is then sealed at a distance from its place of connection with the container. This arrangement keeps the base of the sleeve, where it joins the container, open during the evacuation, to allow a good flow rate of air. There can also for example be provided a relatively stiff ring or weld around the base of the sleeve. It is a particularly simple and convenient arrangement which can utilise a basic vacuum pump with tubular suction nozzle, to dispense with the use of more complex apparatus.

[0007] The arrangement allows particularly easy evacuation using an evacuation pipe or nozzle inserted inside the outer sleeve and with the inner sleeve extending into the pipe. After removal of air either sleeve, or preferably both, can be sealed, e.g. heat-sealed.

[0008] A convenient feature of this arrangement is the facility to remove the seal, e.g. at the end of the sleeve or sleeves, to release the vacuum, e.g. by cutting off the sealed end or ends, and to re-evacuate and re-seal if desired. Depending on the sleeve length, this can be done several times.

[0009] This vacuum-pack arrangement gives an easy and convenient way of packing products to allow economy of shipping bulk and outer packaging material, both because of the compression of compressible materials and because of the rigidification and solidification of flowable or granular or particulate materials packed in such a way.

[0010] Normally, packaging outers have to be of considerable load-bearing strength, and strong enough also to resist the outwardly-directed pressure due to the weight of flowable contents or to the elastic stress of compressed contents.

[0011] With vacuum-packaged materials as described herein, this need no longer be the case, and the function and performance of the outer can be reduced to resisting pinprick or puncture of the airtight bag containing the packed product.

[0012] Also provided according to the invention, therefore, is a vacuum-packaged compressed or granular or particulate product contained in an airtight bag, e.g. having a sealed evacuation sleeve extending therefrom, contained in a packaging outer which protects the bag against puncture and vacuum loss but either would not be strong enough by itself, but for the effect of the vacuum, to bear the weight of a similar packed product placed on top, without distortion, or else would not be strong enough, but for the effect of the vacuum, to contain the contents without distortion.

[0013] Particular embodiments.of the invention can include any of the following features.

[0014] The airtight bags can be made of a thermoplastic material constituting an adequate air barrier, and where needed, an adequate humidity barrier, e.g. polyethylene, or a laminate of polyethylene with high-density polyethylene, nylon, polyvinylidene chloride (PVDC), polyester, aluminium foil, and other suitable materials, e.g. "Cryovac" (TM).

[0015] If the bag is not to be used with an opaque outer, it can be itself opaque, e.g. metallised or metal foil laminated plastics material. The choice of material is very wide and its suitability determined from its air and moisture permeability characteristics and the proposed storage conditions and duration. One suitable material.for many purposes is for excample 0.2-1 mm thick, e.g. 250 micron gauge, low-density polyethylene film.

[0016] The bags can be formed and sealed by any suitable method, e.g. heat-welding for any suitable temperature and time to produce a strong airtight weld seam. In the case of 250 micron LDPE, a few seconds at about 120°-130° is suitable, and ultrasonic welding can be used instead for more rapid effect.

[0017] The evacuation sleeves, e.g. concentric pairs of sleeves extending outwardly from the bags, can be of similar material to that of the baags, and often, if desired, of somewhat lighter gauge, e.g. 125 micron LDPE. The sleeves can be formed with the bags or welded thereto, if desired, more than one sleeve can be used per bag, especially for the larger bag sizes. Two methods of forming the pendent sleeves can in particular be used.

[0018] 

(1) A length of flat thermoplastic tubing can be positioned between two sheets of thermoplastic to be weld-seamed, and extending outwardly from their edges. The assembly is weld-seamed (with a non-sealing tab inserted in the tubing along the line of welding to ensure that the tube remains open). Then the inwardly-extending part of the tubing is inverted and telescoped outwards through the outwardly-extending part so as to form an outwardly-extending double cuff.

(2) Alternatively a double evacuation tube can be heat-welded to extend outwardly from a flanged nipple itself sealingly connected to the bag or container, such as a flanged nipple as shown by numeral 22 in Figures 1-3 of GB Specification No. 1,115,108.

[0019] As an example, a bag to contain about 45 kg powdered leaf tea was made from 250 micron LDPE with a double-sleeve evacuation valve formed by method (2) of two 125 micron LDPE tubes (2 inches lay-flat width). The width of the weld seam between the tubes and bag wall was about ³/₈". The cuff diameter was about 1¹/₄". The bag was filled through its open top, with a plastics foam insert placed in the base of the double cuff to prevent spillage and suction of the contents during evacuation. During the filling and evacuation operation the bag was placed in a rectangular former so that the contents assumed a rectangular block shape. The top was sealed in a usual manner after filling. Evacuation was carried out by inserting a 1¹/₄" diameter end of a metal evacuation pip connected to a vane-type vacuum pump into the outer of the two evacuation sleeves, so that the inner sleeve extended into the pipe. The pump was capable of reducing the pressure to about 1.14 atm (abs) and did so within 40 1 secs. During evacuation the bag contents were tamped down and levelled. The foam insert prevented suction of the bag contents but allowed outflow of air. The contents of the bag became brick-like in consistency. After evacuation, the pump was stopped and the pipe was then 5 removed: then the collapsed inner evacuation sleeve was quickly weld-seamed near its end. Further protection was given by weld-seaming the outer sleeve too. The whole package was put into a (relatively flimsy) 1.5 mm thick cardboard outer (e.g. one that was closely-fitted to the bag shape after evacuation), which proved to have good puncture resistance, although it could not have supported the contents without bulging distortion apart from the effect of evacuation. The outer could not have supported the weight of additional.packages without bursting. Nevertheless, the whole vacuum pack was able to support an impressed load of more than two tons without damage. One further advantage of this construction is that it can be unsealed and resealed at will, after further evacuation if, desired. The relatively flimsy outer can have a flap to allow access to the underlying evacuation sleeve. The end of this can be cut off to allow entry of air and/or further evacuation prior to resealing. If desired, a small quantity of detectable gas, inert with regard to the bag contents, e.g. a halocarbon, (e.g. a Freon (TM)), can be introduced into the bag before evacuation. Such material can be detected by a commercially available halogen ionizing detector, and enables location of leaks even in a largely evacuated bag. If a leak is found it can thus be repaired and the bag if necessary re-evacuated and resealed.

[0020] It can easily be seen that the invention described herein is susceptible of any modifications. Included, for example, are its application to packing compressible fibrous material such as textiles; foam, foam rubber and foam plastics; and granular or particulate materials including tea, grain and bean products such as rice; and powdery or granular chemical products such as for example cement. Pressures less than 0.5 atm, e.g. 0.3 or 0.2 atm down to as little as 0.1 atom may be found suitable. The pipe nozzles for the evacuation can be substituted by other convenient evacuation heads, and any suitable arrangement for keeping the evacuation sleeves open during evacuation can be applied. Where small particles or powder are packed, any suitable filter to prevent loss of contents while allowing airflow out of the evacuation tube can be used.

[0021] An example of an arrangement according to the invention is shown in the Figure, and conforms generally with the description given above. A wall portion 1 of a thermoplastic polymer container lying within an apertured protective outer 2 has a thermoplastic welded double evacuation sleeve welded in any suitable way extending outwardly from it through the aperture. The sleeve comprises an inner sleeve 3 which can conveniently be longer than an outer sleeve 4, though it may be convenient in other arrangements for the lengths to be the same or the reverse. A rigid evacuation nozzle 5 is inserted in between sleeves 3 and 4. After evacuation of the bag, pumping air out in the arrowed direction, at least sleeve 3 tends to collapse on withdrawal of nozzle 5, and sealing is applied in any convenient way, preferably at or near the distal end 6 of the arrangement. Heat-sealing is convenient, and can be used to close off the end of sleeve 3 or of sleeves 3 and 4. An.alternative arrangement has sleeve 3 with an initially closed distal end and a hole at or near the closed end. Sealing can then be achieved by blocking the hole or sealing proximally of it.

Claims

1. A vacuum-sealed packaged product contained in a sealed container which has a double evacuation sleeve of which the interior communicates with the interior of the container, the sleeve extending outwardly from the container and comprising an inner sleeve and an outer sleeve, and sealed at a location spaced away from the place of connection of the sleeve and the container.

2. A vacuum-sealed product according to claim 1, wherein the container comprises a sealed bag of thermoplastic film material contained in an outer to protect against puncture and loss of vacuum.

3. A vacuum-sealed product according to claim 1 or 2, wherein the evacuation sleeve comprises heat-sealed thermoplastic film material.

4. A vacuum-sealed product according to claim 1, 2 or 3, wherein the product contained in the sealed container is a flowable or granular material.

5. A process for vacuum-sealing a product packaged in a container to be evacuated and sealed, which comprises (a) engaging an evacuation sleeve extending from the container with an evacuation nozzle connected to an evacuation pump, (b) evacuating the container via the sleeve and nozzle, and (c) sealing the sleeve, wherein the evacuation sleeve of which the interior communicates with the interior of the container is a double sleeve extending outwardly from the container, and comprising an inner sleeve engaging within the evacuation nozzle and an outer sleeve disposed around and outside the evacuation nozzle to hold open the inner sleeve during step (b), and wherein at least the inner sleeve collapses under atmospheric pressure only upon withdrawal of the nozzle, and the evacuation sleeve is then sealed at a distance from its place of connection with the container.

6. A process according to claim 5, wherein the container comprises a sealed bag of thermoplastic film material contained in an outer to protect against puncture and loss of vacuum.

7. A process according to claim 5 or 6, wherein the evacuation sleeve comprises heat-sealable thermoplastic film material and is heat-sealed in step (c) at a distance from its place of connection with the container.

8. A process according to claim 5, 6 or 7, wherein the product contained in the sealed container is a flowable or granular material.

9. A process for resealing a vacuum-sealed packaged product according to claim 1, which comprises removing the seal located at a distance from the place of connection of the sleeve with the container to leave an outwardly-extending length of the evacuation sleeve remaining, and then evacuating and sealing the opened pack as described in claim 5.

Drawing