GB2412625A

GB2412625A - Container sealing

Info

Publication number: GB2412625A
Application number: GB0407209A
Authority: GB
Inventors: Mark Johnathan Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-03-31
Filing date: 2004-03-31
Publication date: 2005-10-05
Anticipated expiration: 2024-03-31
Also published as: GB2412625A8; GB0407209D0; GB2412625B; GB2412625B8

Abstract

A sealing apparatus comprises a sealing aperture 20 which receives two or more container tabs, such as cooperating inter-engaging sealing edge tabs. A heating element 40 mounted on an actuator 30 is impelled towards the tabs and seals them together by heat and/or heat and pressure. The apparatus may feature more than one aperture (20a, 20b, fig.2) to seal more than one tab at once. The apparatus may further feature activation means 50, user input means 60, ventilation means 70, ventilation apertures 75, a transformer 80 and control means 90. The device may find particular application in the sealing of food containers in shops or retail outlets, from such as salad bars or take away counters.

Description

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24 1 2625

SEALING APPARATUS

The present invention relates to an apparatus for sealing a container, and in particular to an apparatus that may be used within a retail environment to seal containers used to hold, for example, foodstuffs.

Supermarkets have been in recent years expanding the range of product lines offered, such as self-service salad bars or takeaway foods, that are conventionally sold in 'clam shell' containers that are hinged and have a number of mutually engaging peripheral areas, for example an upraised ridge and a groove that receives the ridge, one or more circular protrusions that are received within one or more corresponding apertures, etc., that can be used to provide a partial seal. It is a matter of record that such containers have a number of drawbacks, primarily that it is not possible to seal the containers such that it is readily evident if the sealing of the container has been tampered with.

Furthermore, it is desirable if it is not possible to re-seal the container once it has been opened.

According to a first aspect of the present invention there is provided a sealing apparatus comprising a sealing aperture for receiving two or more container tabs to be fused together and a heating element mounted on an actuator, in use the hot element being impelled towards the tabs, the motion and heat of the element acting to fuse the container tabs.

Preferably the apparatus further comprises control means that controls the magnitude and duration of a first electrical signal that determines the temperature of the heating element ë. e 2 and/or the magnitude and duration of a second electrical signal that determines the motion of the actuator.

The apparatus may further comprise an anvil, the anvil being positioned such that the motion of the actuator presses the tabs against the anvil.

Preferably the apparatus comprises activation means wherein, in use, the fusing of the container tabs is initiated by the activation of the activation means. The apparatus may further comprise a proximity detector for determining the location of the container tabs relative to the heating element and the actuator. The activation means may comprise the proximity detector. The apparatus may further comprise user input means, the user input means, in use, enabling the operation of the apparatus to be varied.

The invention will now be described, by way of example only, with reference to the following Figures in which: Figure 1 shows a schematic depiction of a sealing apparatus according to the present invention; and Figure 2 shows a schematic depiction of a further embodiment of a sealing apparatus according to the present invention.

Figure 1 shows a schematic depiction of a sealing apparatus according to the present invention. Sealing apparatus 10 comprises sealing aperture 20, actuator 30, heating element 40, activation means 50, user input means 60, ventilation means 70, ventilation apertures 75, transformer 80 and control means 90.

a a. a a a a a e a a a a bee eca a ala a äa a ea - 3 - In use, a user will place a tab of a sealable container (see below) into the sealing aperture 20 and activate the activation means 50 to begin the sealing process. The actuator brings the heating element into contact with a first surface of the container tab. The heating element preferably has a narrow profile and the combination of the heat of the heating element and the pressure applied through the motion of the actuator acts to fuse together the two halves of the container tab.

When the activation means is activated a current is applied to the heating element. The control means 90 will determine the current to be applied in accordance with the signals received from the user input means. Preferably the temperature of the heating element is maintained at a substantially constant temperature and the time for which the element is applied to the tabs is varied in order to account for differences in tab thicknesses, material parameters, etc.. The ventilation means 70 is preferably a fan that draws air into the apparatus through the sealing aperture and then expels the air through the ventilation aperture. This air flow helps to cool the tabs such that they will cool and be welded together once the heating element is removed. The ventilation aperture preferably has a significantly greater cross-sectional area than the sealing aperture to provide increased flow velocity through the sealing aperture.

A transformer 80 is provided to step down the mains voltage to a more suitable voltage for operating the apparatus, for example 24V and to provide ac and do signals as required.

Whilst the transformer may be located within the apparatus, e e ese e e e ee e e e e e e e see ë e eve e e e e e bee ee. e e it is preferred to locate the transformer externally to the apparatus as some of the materials in the containers that are to be sealed may affect the operation of the transformer in the event of a spillage, for example some of the oils found in Indian foods are electrically conductive.

The actuator is impelled by the application of an electrical signal and will return to its rest position when the electrical signal is removed. Preferably the actuator comprises a return spring that is compressed by the application of an electrical signal. The return spring will urge the actuator back to its rest position when the electrical signal is removed. The actuator preferably comprises a solenoid that is used to move the heating element into contact with the tabs. In order to increase the pressure applied by the heating element to the tabs it is desirable to have a heating element with a small cross- sectional area.

It is believed that a suitable heating element will have a relatively small diameter, for example approximately 3-4 mm and a length in the range of approximately 10-20 mm (it will be readily understood that elements of other sizes may also be used). The elements should have a power rating of approximately 15-25W which is thought to be capable of maintaining an element temperature of 250-300 C. It is preferred to apply an ac signal to the actuator as this has the beneficial effect of causing the heating element to be impacted into the tabs at the frequency of the ac signal, i.e. 50 Hz for UK mains supply, which assists in the welding together of the tabs.

. . e. . - 5 Figure 2 shows a further embodiment of an apparatus according to the present invention. The apparatus 110 of Figure 2 is similar to that described above with reference to Figure 1 and common components will be described using the same reference numerals. It will also be readily understood that the components described below with reference to Figure 2 may be used with the apparatus described above with reference to Figure 1.

Apparatus 110 comprises two sealing apertures 20a, 20b (and it will be readily apparent that more apertures may be provided). This enables containers having two (or more) tabs to be fused in a single process. The apparatus 110 further comprises first actuator 30 and second actuator 35: the heating element 40 is received on the first actuator 30 and the second actuator 35 acts to press the two tabs together.

Once the first actuator is retracted, the second actuator will continue to press the tabs whilst the tabs cool, to reduce the chance of the two tabs becoming separated once the container is removed from the apparatus The apparatus may also comprise an anvil 38 which is located such that the actuator(s) clamp the tabs together against a flat surface of the anvil, which will also assist in the fusing together of the two tabs. A proximity sensor 39 may be provided such that the correct positioning of the tabs relative to the actuator(s) can be indicated to a user, for example by providing a visual or audible indication, to prompt the user to activate the activation means.

e C C C C ce.. c tee . . C C - 6 Alternatively, the proximity sensor may comprise the activation means. When the proximity sensor indicates that the tabs are correctly located within the sealing aperture(s), the control means send an appropriate signal to the actuator(s) and the heating element to initiate the sealing process. A visual or audible indication may be provided to indicate to a user that the sealing process has been completed. Such an arrangement simplifies the operation of the apparatus and also enables the apparatus to operated whilst still holding the container to be sealed with both hands.

The user input means may comprise a number of different forms. At the most simple, a user may select the type of container to be sealed, with the control means containing pre-programmed parameters for the heating element temperature, the time for which the actuator is in contact with the tabs, etc. Alternatively, the user may be able to determine the values to be used for one or more of these parameters, for example by inputting numerical values or selecting one of a number of pre-set values.

The ventilation means may operate at a substantially constant speed, or the speed of the ventilation means my be increased as required in order to inverse the flow-rate through the sealing aperture(s) as appropriate, for example once the heating element has been removed but the tabs are still being pressed by the actuator(s).

In a preferred embodiment of the present invention, a heating current may be permanently supplied to the heating element to maintain the element at an elevated standby temperature, with : : : ë: :. A: :: ae: sea A - 7 - a further current being applied in use to bring the element up to the required operating temperature. It is thought that a suitable operating temperature is 250-300 C and thus the standby element temperature may be in excess of 200 C. In this case, a small volume heating element is preferred as it reduces the electrical power required to maintain the element at its standby temperature. This in turn reduces the excess heat that needs to be vented from the apparatus.

The containers for use with the apparatus are similar to known 'clamshell' containers that clip together, except that the container comprises one or more pairs of tabs that are brought together when the container is closed.

Alternatively, one of the halves of the container may comprise two hinged tabs which fold around the tab located on the other half of the container to from a triple-tab arrangement.

Claims

e e #e e e e e e # c # ë e ce e e see ee. e e - 8 CLAIMS

1. A sealing apparatus comprising a sealing aperture for receiving two or more container tabs to be fused together and a heating element mounted on an actuator, in use the hot element being impelled towards the tabs, the motion and heat of the element acting to fuse the container tabs.

2. A sealing apparatus according to claim 1, wherein the apparatus further comprise control means that controls the magnitude and duration of a first electrical signal that determines the temperature of the heating element.

3. A sealing apparatus according to claim 1 or claim 2, wherein the apparatus further comprise control means that controls the magnitude and duration of a second electrical signal that determines the motion of the actuator.

4. A sealing apparatus according to any preceding claim further comprising an anvil, the anvil being positioned such that the motion of the actuator presses the tabs against the anvil.

5. A sealing apparatus according to any preceding claim further comprising activation means wherein, in use, the fusing of the container tabs is initiated by the activation of the activation means.

6. A sealing apparatus according to any preceding claim further comprising a proximity detector for determining the Bea a * a ee I lea ë ë a _ 9 _ location of the container tabs relative to the heating element and the actuator.

7. A sealing apparatus according to any claim 6 when dependent upon claim 5, wherein the activation means comprises the proximity detector.

8. A sealing apparatus according to any preceding claim further comprising user input means, the user input means, in use, enabling the operation of the apparatus to be varied.

9. A sealing apparatus substantially as described hereinbefore and with reference to Figures 1 & 2.