CA1291412C - Vacuum packaging apparatus and process - Google Patents
Vacuum packaging apparatus and processInfo
- Publication number
- CA1291412C CA1291412C CA000413519A CA413519A CA1291412C CA 1291412 C CA1291412 C CA 1291412C CA 000413519 A CA000413519 A CA 000413519A CA 413519 A CA413519 A CA 413519A CA 1291412 C CA1291412 C CA 1291412C
- Authority
- CA
- Canada
- Prior art keywords
- receptacle
- pressure
- gas
- chamber
- extraction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Vacuum Packaging (AREA)
Abstract
ABSTRACT
"VACUUM PACKAGING APPARATUS AND PROCESS"
A vacuum packaging process and apparatus employ the novel step of deliberatety at least partically repressurizing the exterior of a packaging receptacle after commencement of the evacuation of the exterior and interior of the receptacle in a chamber. Two separate gas pressure restroation phases may be employed, separated by a resumption of the gas extraction, and the receptacle is closed during the second of these gas pressure restoration phases.
"VACUUM PACKAGING APPARATUS AND PROCESS"
A vacuum packaging process and apparatus employ the novel step of deliberatety at least partically repressurizing the exterior of a packaging receptacle after commencement of the evacuation of the exterior and interior of the receptacle in a chamber. Two separate gas pressure restroation phases may be employed, separated by a resumption of the gas extraction, and the receptacle is closed during the second of these gas pressure restoration phases.
Description
DESCRIPTION
"VACUUM PACKAGING APPARATU5 AND PROCES~"
The present invention relates to a process of and apparatus for packaging an article in a receptacle to obtain a vacuum pack.
Hitherto it has been known to package an article in 10 a plastics envelope, such as a plastic bag, by loading the article in the envelope and then inserting the loaded envelope into a vacuum chamber for the atrnosphere around the envelope to be reduced in pressure so that the air or other gas within the envelope is extracted and finally the envelope can be sealed under low pressure conditions. The resulting package is termed a "vacuum package".
.
I t is also known for the operation of the process ~o be such that during the reduction in pressure of the atmosphere 20 around the envelope, the wal I of the envelope baloons away from the enclosed article, so that the extraction of air from within the envelope can be more effectively carried out. Such a system has, ~or example, been disclosed in U.S. Pa~ent N~. 3 714 754 (Holcombe) using a nozzle to extract air from within the envelope 25 while the pressure of the atmosphere around the envelope has ~, -~29~12 reduced to effect the necessary ballooning action. Ballooning has furthermore been disclosed in U.S. Patent No. 3 832 824 (Burrel I ) in which the vacuum chamber in which the envelope is closed 5 has two portions of which a first portion encloses the envelope mouth and the second portion encloses the article-enclosing remainder of the envelope so that the pressure around the exterior of the envelope can initially be reduced more rapidly than the pressure within the envelope ( ;n order to promote the 10 desired bal looning effect) . Such a process is suitable for a high vacuum pack when a long evacuation step can be tolerated.
Furthermore, sealing the pack while it is in a ballooned condition wilI give rise to uncertainty of the volume of residual air still in the pack at the time of sealing, leading to 15 uncertainty of the air pressure within the sealed bag when the pack exterior is returned to atmospheric pressure outside the chamber .
When using such process for packing products 20 having a porous structure the high vacuum applied can remove air out of the product so that the structure of the product will be destroyed or at leas~ damaged.
It has further been found that, with these prior art 25 arrangements, when a short evacuation step (for example for a - ~2~41;2 so-called soft vacuum pack) is needed, there is a possibility for air to become trapped behind the produc-t article and for pockets of such air to be trapped within the sealed pack.
It is an object of the present invention to provide an improved method and appara-tus for packaging articles in a receptacle so as to overcome the disadvantages of -the prior art.
Accordingly, the present invention provides a process for vacuum packaging an ar-ticle in a flexible recep-tacle, compris-ing loading the article in the receptacle, extracting gas from around the exterior of the receptacle to lower the surrounding pressure, extracting gas from within the receptacle, and closing the receptacle in a gas-tight manner after the extraction of gas from i-ts interior, characterized in that after the pressure sur-rounding the receptacle has been initially lowered, tha-t pressure is raised in a pressure restoration phase, before the receptacle is closed, said pressure restoration phase being started at a predetermined pressure difference between the pressure surrounding the receptacle and the pressure within the receptacle, the closing of the receptacle being carried out immediately after the recep-tacle has been pressed against the exterior of the article, andafter said pressure restoration phase the pressure surrounding the receptacle is lowered in a further pressure reduction step before the receptacle is closed.
When the pressure is raised around the receptacle after an initial lowering oE pressure the receptacle will be pressed against the product so that gas located between the outer surface of the article and the receptacle will he pressed out oE the recep-tacle. Thereafter the receptacle can be closed. Since such way of ,~
pressing gas out of the receptacle does not require a high vacuum the structure of the article will not be damaged and a "so-ft vacuum" pack is obtained.
It is also possible to provide for another pressure restoration phase. This results in a repeated inward and outward oscillation of the wall of the receptacle and in a "pumping effect"
removing gas trapped in pockets in the pack.
A further aspect of the present invention provides apparatus :Eor vacuum packaging, comprising a vacuum chamber having an extraction pump for extracting gas from within the interior of the chamber and a support for a loaded flexible receptacle to be evacuated and sealed in the chamber; and means for closing a receptacle in the chamber; characterized by means for restoring pressure to the exterior of a receptacle disposed within the vacuum chamber after partial evacuation of the chamber by the extraction pump before the receptacle is closed, programming means being provided to ensure further pressure reduction in the chamber after operation of the pressure restoration means.
In order that the present invention may more readily be understood the following description is given, merely by way of example, with reference to the accompanying drawings in ~.
4~i~
which:- -.
Figure 1 is a schematic side elevational view of a first embodiment of vacuum packaging apparatus in accordance with the present invention;
Figure 2 is a view similar to Figure 1 but showing a second embodiment of apparatus in accordance : 10 with the invention;
Figure 3 is a cycle timing diagram showing the residual pressure P in the chamber plotted against time of the cycle;
Figure 4 is a v;ew similar to Figure 1 but showing the apparatus during operation of the vacuum pump and with the air admission valve closed;
Figure 5 is a view similar to Figure 4 but showing the effect of the a;r admission valve in the open configuration;
Figure 6 is a view similar to Figure 5 but showing the envelope-closing mechanism in operation; and ,, , . , . ,. . ~ . _. , . ... _ ,... ... _ ,.. ...... ~.,, ._,.. .. . ,, .. _ .... .
1~9~4~LZ, Figure 7 is a cycle diagram of another process in accord--~ .ance with the invention.
The vacuum chamber 1 shown in Figure l is of a conventional form and includes a vacuum enclosure comprising a cover 2 on a base 3 to which the cover is sealed along its rim 4. An air extraction duct 5 leads to an extraction pump 6 whose discharge duct 7 conveys away air which has been extracted from the chamber 1. -The chamber further includes a receptacle-closing unit 8 -having a driven mechanism 9, here comprising a pair of opposed hot weld bars 10 which are driven towards one another to conta~ct the neck region of the receptacle 11 (in this case a plastic bag of heat shrinkable thermoplastic material) and are energized with a pulse of electric energy to heat seal the neck region of the envelope before the chamber 1 opens. This closing unit is also associated with an optional yieldable bag holding means 21, here shown as a resilient blade ~2 clamped along one edge (in this case the upper edge) and having its opposite, free edge ~in this case the lower e'dge) disposed nearer to the bag mouth and nearer to an opposed anvil 23.
The embodiment of the present invention provides for ~X9~4~2 the incorporation of an air admission valve 12 on -the chamber -' cover 2 to admit air into the chamber while the extraction pump 6 is in operation. This unexpected modification has the surpri-5 sing advantage of being able to allow more effective extractionof air from within the receptacle 11 provided the air admission value is operated in accordance with the process of the present invention .
The air admission valve 12 includes an airflow regulator lever 13 allowing a throtlle 14 to be adjusted to give the des;red rate of venting of the valve 12 when in its open configuration. Furthermore, the valve 12 is connected, by pneumatic control line - 15, to a pneumatic control unit 16 which 15 provides signal pulses to the valve 12 in response to the vacuum level in the chamber 1 as sensed by way of a sensing conduit 17. It is expected that the reate of admission of air through the throttle 14 wil I be grater than the rate of extraction by the pump 6.
The control unit 16 for the air admission valve 12 includes a selector control 19 allowing adjustment of the parti-cular valve of the residual pressure within the chamber l at which the valve 12 is opened and closed.
., .. ., ... _ .. ... ... , .... ... _.. _ . ,, . . , . . _. _ .. . ... . . .
lZ9~4~
-~As will be indicated below, making the~ control unit 16 responsive to the chamber pressure is an optional feature, although this type of control does provide a particularly convenient way of controlling the operation of the air admission valve 12 when carrying out the process of the present inventior,.
To perform the process in accordance with the invent-10 ion, the chamber cover 2 is closed over the open receptacle 11 with article 18 therein, and the extraction pump 6 is energized to begin extraction of air from within the chamber 1 and consequently from within the receptacel 11 tby virtue of the neck region being -y;eldable .held by the. holding means. 21 in the 15 region adjacent the two spaced welding bars 10 of the closing mechanism 8).
Ideally the welding bars lO are, during extraction, spaced apart such that air is extracted at a control led rate from 20 within the receptacel 11 as the blade 22 yields, and this rate~of extraction is less than the rate of pressure decrease in the atmosphere within the chamber 1 but ar;:>und the exterior of the receptacle 11, with the result that the receptacle 11 balloons outwardly away from the article 18.
~ ~ . ~ . .. . . . .. . ...... . .
,, ' 1'~914~2 g--According to the invention, the air admission valve ~- 12 should then be opened in order to vent air into the end of the chamber 1 where the ar~icle-enclosing part of the bag is 5 located (preferably by simply opening the chamber 1 directly to atmosphere to al low atmospheric air to mix with the residual atmosphere around the exterior of the receptacle 11 ) . Where the receptacel has already ballooned away from the article, this venting has the result that the receptacle 11 is pressed inwardly 10 against the exterior of the article 18.
During this gas pressure restoration phase, the extraction of air from within the receptacle 11 will continue and in the case of a flexible bag 11 the thrusting of the flexible 15 bag material 11 onto the product article helps to "pump" air from within the bag 11. The operation of the air admission valve ancl the extraction pump, as wel I as of the receptacle closing means 8 is control led by a programmer 20 which maintains the pump 6 in operation even during gas pressure restoration phases.
Where a yieldabJe bag holding means 21 is included, the blade 22 will remain in its "yielded" position (due to its elastic nature and its particular inclination) while air is being ;25 expelled from within the bag but will close off the bag neck ~91~
.
- l o -when air pressure outside the bag neck region ha~s risen to a ~_ value which impedes air venting from the bag.
The air pressure restoration phase is of limited duration so that when the air admission valve 12 i5 reclosed the continuing operation of the extraction pump 6 will effect extract-ion of the now slightly higher pressure atmosphere around the bag 11, while still evacuating the lower pressure inlerior of the bag 11. This extraction of the external air from around the bag 11 may shortly result in recurrence of the ballooning phenomenon, whereupon the air admission valve 12 is once again opened to buiId up gas pressure around the bag 11 to thrust the bag material onto the article 18 to achieve a pulsating reinforce-~15 ment_of the air extraceion from within the bag 1.
It is envisaged that this pulsating action of success-ful pressure reductions followed by pressure increases on the exterior of the receptacle can continue until a desired configur-ation has been obtained at which time the receptacle 11 is closedby operation of the closing means 8 when its actuating means 9 are energized. However, it is preferred for the cycle to continue for only two repressurization pulses, even though the use of more than two such pulses is within the scope of such process according to the present invention.
,.
.. , ................ . _ .. _ ... _ ~9~4~2 Figure 2 i I iustrates an alternative embo~iment of the -~ apparatus in accordance with the present inventi~n, differing only in that the air admission valve 12 is connected in the 5 extraction duct 5 to the pump 6. The functional result will be the same in that the successive opening and closing of the air admission valve 12 superimposed on the continuous operation of the extraction pump 6 will achieve a pulsating pressure in the residual atmosphere around the receptacle 11 in both Figure 1 10 and Figure 2. It wil I of course be understood that the air admission valve 12 in Figure 1 need not be incorporated on the cover 2; air admission means of any suitable form could be - used, for example a valve connected to an air admission port i~
the base 3 inwardly of the position occupied by the rim 4 of the 15 cover 2 in the closed configuration of the chamber.
, ' The embodiment of Figure 2 also includes an adjust-able throttle valve 14 havin~ a control lever 13, and an adjuster 19 on the control unit 16 for selecting a different 20 pressure value at which the air admission valve 12 is to open or c lose .
Although, in Figure 1 and in Figure 2, the air admission valve 12 is operated in response to attainment of 25 particular pressure valve in the chamber 1, as indicated above, , . .. .... . . . . .. .. ..
:: :
-~, ~Z9~412 it is not essential for the control of the air admiss~on valve to be responsive to chamber pressure. For example,~ the control unit 16 may be a pulsing controller of a pneumatic type which 5 imposes pressure of suction pulses on the control line 15 to the air admission valve 12 at predetermined time intervals after commencemennt of the evacutation of the chamber 1. Alter-natively, the control unit 16 rnay not be pneumatic but may be connected So the valve 12 by a mechanical linkage or by an 10 electrical linkage, in which case the pressure- or time-responsive controller will be of a mechanical or an electrical type~ respect-ively. Yet a further possibility suitable where the receptacle is a plastic envelope is for a nnechanical feeler unit to be incorporated within the chamber 1 in order to detect when the 15 flexible envelope such as bag 11 balloons, since the ballooned state of the bag 11 at the instant of the opening of the air admission valve 12 assists the extraction operation.
Throughout the following description, the mechanism 20 f Figure 1 for use with plastics flexible bags 11 will be described in its detai led operating cycle, with reference to the cycle diagram of Figure 3 and with reference to Figures 4, 5 and 6 showing the apparatus of Figure 1 at different states in its operating cycle. It wlll of course be appreciated that the 25 different locations of the control line 15a and the sensing line . ~, ..... . ... .. . . .... .....
~29~412 .
17a in Figures 4 to 6 with respect to the posi,tions of the corresponding lines 15 and 17 in Figures 1 i5 of no functional significance but is simply to illustrate the fact that the routing of these lines is purely optional at the discretion of the machine designer.
Figure 3 shows that at the start of a typical operating cycle the pressure within the chamber is at a value Pl, normally the atmospheric pressure in the packaging room.
The machine is set up by adjusting the throttle control lever 13 to give the desired air admission rate, and also adjustiny the pressure control 19 to select a particular pressure at which the control unit 16 operates to create a signal pulse in control line 15. This pressure P2 is shown in Figure.3.
Referring now to the operating cycle depicted in Figure 3, once that chamber 1 is closed the pressure P reduces 20 from initial value P1 at point I to a value P2 which has been preset on the control 19, and at which the control unit 16 sends a signal pulse to the valve 12. As this pulse is being transmitted to the valve 12, the pressure P is till reducing below the value P2 between points ll and point lll on the 25 pressure/time curve. ~he opening of the air admission valve 12 ' ~'~9~43L~
will, howeverj result in a reduction in the rate of extraction of ~ air by the pump 6 and consequently the pressure P bottoms out at a value P3 at point lll~ and then begins to rise towards the value P2 which is attained at point IV on the curve. At this point the control unit 16 emits another signal pulse closing the air admission valve 12, but nevertheless there remains an upward swing in the pressure value towards the point V on the curve. This upward swing flattens out at point V at pressure value P~, and the pressure then begins to reduce towards point Vl on the curve. The above-described sequence of events between points ll, Ill, IV and V is repeated between points Vl, Vll, Vlll and IX. However, somewhere between points Vll ar,d IX the receptacle-closing unit 8 is operated to seal the bag 11 while the pressure around the bag is increasing and pumping out residual air from within the enverope. This is a preferred aspect of the invention and ensures optimum elimination of trapped bubbles of air or other gas from within the bag 1.
It is particularly preferable for the programmer 20 to trigger the closing action to occur between points Vlll and IX, so that the repressurization pulse on the envelope has had a chance to build up momentum.
' 25 It will readily be appreciated that the flexible bag .. . ... . . . .... . . ......
~29~4~Z
11 balloons at some stage between points I and l~l, collapses -- between points lll and V, balloons again between ~points V and Vll and collapses between points Vll and IX.
Where a particularly high vacuum (low residual pressure) is required within the bag 11, it may be envisaged that the receptacle-closing means 8 are operated between points Vl and Vll or between corresponding points on a further descending half cycle of the curve after point IX.
The process described above has been performed successfully for the packaging of cheese where a relative~y "soft" vacuum is advantageous but where the size of the cheese pack may be such that conventionally the air extraction operat-ion takes a considerable time. It has been found that the extraction time is reduced wtih such process in accordance with the present invention and the occurrence of trapped gas pockets in the pack (particularly likely in the case of Emmental cheese having cavities formed in the surface of the cheese block) is reduced. Although the present invention is not to be limited by any speculation on the functional advantages of the process, it is thought that the inward and outward oscillation of ~he wall of the receptacle (in the case of a flexible bag 11) due to the pulsating pressure on its exterior results in a pumping action .. .. . . . .. . ... . . . ..... . ., , . . , .. _, . . . . . ... . .. .
1~9~L2 which urges escape of gas (e.g. air) through the -neck of the -~ bag 1l with great momentum while the bag is sti~-i ballooned, and that this assists in persuading trapped gas pockets to 5 escape. Furthermore, this ensures that the residuai pressure right through the pack is more uniform than is possibie with prior art vacuum packaging processes.
It is envisaged that the process described wil I be 10 equally applicable to high vacuum (low residual pressure) pack-aging as to "soft vacuum" packaging (with relatively higher residual pressure values).
Figure 4 i I lustrates the condition of the apparatus 15 between points 1, ll and lll of the cycle diagram of Figure 3.
This same configuration applies between points V, Vl and Vll.
The extraction. pump 6 is in operation but the air admission valve 12 is closed.
Figure 5 illustrates the configuration between points I l l, IV and V in the cycle diagram of Figure 3. This configuration is repeated between points Vll, Vlll and IX. The air admission valve receives a signal along the signal line 15_ and opens to admit air into the chamber 1.
.
~X91~
Figure 6 illustrates the configuration at one instant ~~ during the interval between points ~111 and IX, sh~rtly before point IX, when the control unit 16 transmits a signal pulse along the signal line lSa and closes the air admission valve 12 while the receptacle-closing means 8 are actuated to seal the envelope.
The apparatus in accordance with the present invent-ion can also be used to produce a "soft vacuum" packaging whenoperated as shown in the cycle diagram of Figure 7.
At the start of such process-the pressure within the chamber is at a value P1, normally the atmospheric pressure in the packaging room. The machine is then set up as described in connection with Figures I to 6 and the pressure PCH in the chamber is reduced which~also results in a reduction of pressure PR in the receptacle. In the present process in accordance with the invention, it is not important to reach a predetermined value 2~ of pressure PCH but a sufficient pressure difference between the pressure PCH and the pressure Pp.
If a sufficient pressure difference has been generated, e.g. a pressure difference of about lSO mb for a ptastic bag as usually used for producing such packings, then -- ---..- .......
~z~
- . the .:chamber 1 wil.l be vented by opening the air adrr.ission valve 12. In the op.erating cycle depicted in Figure 7 this occurs at the time T1 and the pressure PCH in chamber 1 will increase 5 rapidly upto P1, whereas there will be no increase or almost no increase of pressure PR in the receptacle. By such increase of pressure PCH the flexible receptacle 11 is pressed inwardly against the exterior of the article 18 and the air located between the receptacle and the exterior of the article is pressed 10 out of the neck of the receptacle 11. Preferably, the extraction pump 6 is kept in operation during venting of chamber 1.
In the process described in connection with Figuré
7, generation of a high vacuum is avoided and the vacuum 15 applied shall not be larger than required to obtain the necessary pressure difference between pressure PCH and pressure PR. Therefore, removal of air from~ the interior of article 18 is minimized whereas the air located between the exterior of article 18 and receptacle 11 is effectively removed.
As it is preferre?d to suddenly press- inwardly the receptacle 11 against the exterior of the article 18 to rernove the air located between the receptacle 11 and the ex~erior of the article 18, the apparatus shown in Figures 1 and 2 and 4 to 6 25 would not require a throttle 14 but venting of chamber 1 shoutd : , , ~'~91~Z
be effected in such a way tha~ increase of pressure PCH is_ -- obtained within the shortest time possible, i.e. t-he pressure curve PCH shown in Figure 7 shall have a very high steepness 5 starti ng at T1 immediately after the receptacle 11 has been pressed against the exterior of the article 18 which s~ep has been completed at time T2 in the operation circle depicted in Figure 10 7~ the receptacle 11 wil I be closed by means of the receptacle-closing means 8. Such closing will take place not later than 0.5 seconds after the time T2 of Figure 7 since otherwise air from chamber 1 might enter the neck portion of receptacle 11.
If desired, the sealed receptacle 11 may be subject-ed to a shrinking operation to cause the receptacle material to contact the article 18 intimately.
Although it is envisaged that the apparatus in accordance with the present invention may be equipped from the outset with repressurization means such as the air admission valve 12, it is also within the scope of the present invention for an ex7sting vacuum chamber machine to be modified, simply by the addition of repressurization means such as the air admission valve 12 (and suitable control means therefor) either on the ~L2~
chamber 1 or on the extraction conduit 5, so as t~ modify that - existing machine to operate in accordance with the~-processes of the present invention.
.
Although, in the above description, the envelope-closing means 8 comprises a heat sealing bar arrangement, other suitable closing mechanisms may be provided, For exarnple radiant heat fusion sealing means operating in conjuction with 10 the yieldable holding means 21 to allow escape of air from within the receptacle 11 before the emission of a radiant heat pulse to cause the receptacle to fuse upon pressing contact with itself by the increasing pressure in the chamber 1 between points Vl I and IX of Figure 3 or between T2 and T3 In Figure 7.
1~ :
Other closing systems such as a gathering and clipping mechanism may instead be provided. Likew7se, although the apparatus i I lustrated in Figures 1, 2, 4, 5 and 6 shows a single, open chamber, it is of course possible ~or the processes zO of the present invention to be carried ou~ using the "in-chamber nozzle" disclosed in the above mentioned U.S. Patent No. 3 714 754 (Holcombe), or in the double chamber construction disclosed in the above mentioned U.S. Patent No. 3 B32 824 (Burrel I ) .
As mentioned above, the operation of the air .. : . ,, .,, .. ,, .. , ,. , ., . , . . . . .. , .. . _ _ ... .. ... . . . . .
L4~
admission valve 12 may be controlled simply on the basis of time -~ elapsed since the start of the cycle, or in response-to operation of a mechanical feeler, and both of these control mechanisms can 5 be incorporated as modifications to existing vacuum chamber packaging equipment.
. , , . . . .. . .. .... .. _ .. _ ... . . ..... .... . . .
"VACUUM PACKAGING APPARATU5 AND PROCES~"
The present invention relates to a process of and apparatus for packaging an article in a receptacle to obtain a vacuum pack.
Hitherto it has been known to package an article in 10 a plastics envelope, such as a plastic bag, by loading the article in the envelope and then inserting the loaded envelope into a vacuum chamber for the atrnosphere around the envelope to be reduced in pressure so that the air or other gas within the envelope is extracted and finally the envelope can be sealed under low pressure conditions. The resulting package is termed a "vacuum package".
.
I t is also known for the operation of the process ~o be such that during the reduction in pressure of the atmosphere 20 around the envelope, the wal I of the envelope baloons away from the enclosed article, so that the extraction of air from within the envelope can be more effectively carried out. Such a system has, ~or example, been disclosed in U.S. Pa~ent N~. 3 714 754 (Holcombe) using a nozzle to extract air from within the envelope 25 while the pressure of the atmosphere around the envelope has ~, -~29~12 reduced to effect the necessary ballooning action. Ballooning has furthermore been disclosed in U.S. Patent No. 3 832 824 (Burrel I ) in which the vacuum chamber in which the envelope is closed 5 has two portions of which a first portion encloses the envelope mouth and the second portion encloses the article-enclosing remainder of the envelope so that the pressure around the exterior of the envelope can initially be reduced more rapidly than the pressure within the envelope ( ;n order to promote the 10 desired bal looning effect) . Such a process is suitable for a high vacuum pack when a long evacuation step can be tolerated.
Furthermore, sealing the pack while it is in a ballooned condition wilI give rise to uncertainty of the volume of residual air still in the pack at the time of sealing, leading to 15 uncertainty of the air pressure within the sealed bag when the pack exterior is returned to atmospheric pressure outside the chamber .
When using such process for packing products 20 having a porous structure the high vacuum applied can remove air out of the product so that the structure of the product will be destroyed or at leas~ damaged.
It has further been found that, with these prior art 25 arrangements, when a short evacuation step (for example for a - ~2~41;2 so-called soft vacuum pack) is needed, there is a possibility for air to become trapped behind the produc-t article and for pockets of such air to be trapped within the sealed pack.
It is an object of the present invention to provide an improved method and appara-tus for packaging articles in a receptacle so as to overcome the disadvantages of -the prior art.
Accordingly, the present invention provides a process for vacuum packaging an ar-ticle in a flexible recep-tacle, compris-ing loading the article in the receptacle, extracting gas from around the exterior of the receptacle to lower the surrounding pressure, extracting gas from within the receptacle, and closing the receptacle in a gas-tight manner after the extraction of gas from i-ts interior, characterized in that after the pressure sur-rounding the receptacle has been initially lowered, tha-t pressure is raised in a pressure restoration phase, before the receptacle is closed, said pressure restoration phase being started at a predetermined pressure difference between the pressure surrounding the receptacle and the pressure within the receptacle, the closing of the receptacle being carried out immediately after the recep-tacle has been pressed against the exterior of the article, andafter said pressure restoration phase the pressure surrounding the receptacle is lowered in a further pressure reduction step before the receptacle is closed.
When the pressure is raised around the receptacle after an initial lowering oE pressure the receptacle will be pressed against the product so that gas located between the outer surface of the article and the receptacle will he pressed out oE the recep-tacle. Thereafter the receptacle can be closed. Since such way of ,~
pressing gas out of the receptacle does not require a high vacuum the structure of the article will not be damaged and a "so-ft vacuum" pack is obtained.
It is also possible to provide for another pressure restoration phase. This results in a repeated inward and outward oscillation of the wall of the receptacle and in a "pumping effect"
removing gas trapped in pockets in the pack.
A further aspect of the present invention provides apparatus :Eor vacuum packaging, comprising a vacuum chamber having an extraction pump for extracting gas from within the interior of the chamber and a support for a loaded flexible receptacle to be evacuated and sealed in the chamber; and means for closing a receptacle in the chamber; characterized by means for restoring pressure to the exterior of a receptacle disposed within the vacuum chamber after partial evacuation of the chamber by the extraction pump before the receptacle is closed, programming means being provided to ensure further pressure reduction in the chamber after operation of the pressure restoration means.
In order that the present invention may more readily be understood the following description is given, merely by way of example, with reference to the accompanying drawings in ~.
4~i~
which:- -.
Figure 1 is a schematic side elevational view of a first embodiment of vacuum packaging apparatus in accordance with the present invention;
Figure 2 is a view similar to Figure 1 but showing a second embodiment of apparatus in accordance : 10 with the invention;
Figure 3 is a cycle timing diagram showing the residual pressure P in the chamber plotted against time of the cycle;
Figure 4 is a v;ew similar to Figure 1 but showing the apparatus during operation of the vacuum pump and with the air admission valve closed;
Figure 5 is a view similar to Figure 4 but showing the effect of the a;r admission valve in the open configuration;
Figure 6 is a view similar to Figure 5 but showing the envelope-closing mechanism in operation; and ,, , . , . ,. . ~ . _. , . ... _ ,... ... _ ,.. ...... ~.,, ._,.. .. . ,, .. _ .... .
1~9~4~LZ, Figure 7 is a cycle diagram of another process in accord--~ .ance with the invention.
The vacuum chamber 1 shown in Figure l is of a conventional form and includes a vacuum enclosure comprising a cover 2 on a base 3 to which the cover is sealed along its rim 4. An air extraction duct 5 leads to an extraction pump 6 whose discharge duct 7 conveys away air which has been extracted from the chamber 1. -The chamber further includes a receptacle-closing unit 8 -having a driven mechanism 9, here comprising a pair of opposed hot weld bars 10 which are driven towards one another to conta~ct the neck region of the receptacle 11 (in this case a plastic bag of heat shrinkable thermoplastic material) and are energized with a pulse of electric energy to heat seal the neck region of the envelope before the chamber 1 opens. This closing unit is also associated with an optional yieldable bag holding means 21, here shown as a resilient blade ~2 clamped along one edge (in this case the upper edge) and having its opposite, free edge ~in this case the lower e'dge) disposed nearer to the bag mouth and nearer to an opposed anvil 23.
The embodiment of the present invention provides for ~X9~4~2 the incorporation of an air admission valve 12 on -the chamber -' cover 2 to admit air into the chamber while the extraction pump 6 is in operation. This unexpected modification has the surpri-5 sing advantage of being able to allow more effective extractionof air from within the receptacle 11 provided the air admission value is operated in accordance with the process of the present invention .
The air admission valve 12 includes an airflow regulator lever 13 allowing a throtlle 14 to be adjusted to give the des;red rate of venting of the valve 12 when in its open configuration. Furthermore, the valve 12 is connected, by pneumatic control line - 15, to a pneumatic control unit 16 which 15 provides signal pulses to the valve 12 in response to the vacuum level in the chamber 1 as sensed by way of a sensing conduit 17. It is expected that the reate of admission of air through the throttle 14 wil I be grater than the rate of extraction by the pump 6.
The control unit 16 for the air admission valve 12 includes a selector control 19 allowing adjustment of the parti-cular valve of the residual pressure within the chamber l at which the valve 12 is opened and closed.
., .. ., ... _ .. ... ... , .... ... _.. _ . ,, . . , . . _. _ .. . ... . . .
lZ9~4~
-~As will be indicated below, making the~ control unit 16 responsive to the chamber pressure is an optional feature, although this type of control does provide a particularly convenient way of controlling the operation of the air admission valve 12 when carrying out the process of the present inventior,.
To perform the process in accordance with the invent-10 ion, the chamber cover 2 is closed over the open receptacle 11 with article 18 therein, and the extraction pump 6 is energized to begin extraction of air from within the chamber 1 and consequently from within the receptacel 11 tby virtue of the neck region being -y;eldable .held by the. holding means. 21 in the 15 region adjacent the two spaced welding bars 10 of the closing mechanism 8).
Ideally the welding bars lO are, during extraction, spaced apart such that air is extracted at a control led rate from 20 within the receptacel 11 as the blade 22 yields, and this rate~of extraction is less than the rate of pressure decrease in the atmosphere within the chamber 1 but ar;:>und the exterior of the receptacle 11, with the result that the receptacle 11 balloons outwardly away from the article 18.
~ ~ . ~ . .. . . . .. . ...... . .
,, ' 1'~914~2 g--According to the invention, the air admission valve ~- 12 should then be opened in order to vent air into the end of the chamber 1 where the ar~icle-enclosing part of the bag is 5 located (preferably by simply opening the chamber 1 directly to atmosphere to al low atmospheric air to mix with the residual atmosphere around the exterior of the receptacle 11 ) . Where the receptacel has already ballooned away from the article, this venting has the result that the receptacle 11 is pressed inwardly 10 against the exterior of the article 18.
During this gas pressure restoration phase, the extraction of air from within the receptacle 11 will continue and in the case of a flexible bag 11 the thrusting of the flexible 15 bag material 11 onto the product article helps to "pump" air from within the bag 11. The operation of the air admission valve ancl the extraction pump, as wel I as of the receptacle closing means 8 is control led by a programmer 20 which maintains the pump 6 in operation even during gas pressure restoration phases.
Where a yieldabJe bag holding means 21 is included, the blade 22 will remain in its "yielded" position (due to its elastic nature and its particular inclination) while air is being ;25 expelled from within the bag but will close off the bag neck ~91~
.
- l o -when air pressure outside the bag neck region ha~s risen to a ~_ value which impedes air venting from the bag.
The air pressure restoration phase is of limited duration so that when the air admission valve 12 i5 reclosed the continuing operation of the extraction pump 6 will effect extract-ion of the now slightly higher pressure atmosphere around the bag 11, while still evacuating the lower pressure inlerior of the bag 11. This extraction of the external air from around the bag 11 may shortly result in recurrence of the ballooning phenomenon, whereupon the air admission valve 12 is once again opened to buiId up gas pressure around the bag 11 to thrust the bag material onto the article 18 to achieve a pulsating reinforce-~15 ment_of the air extraceion from within the bag 1.
It is envisaged that this pulsating action of success-ful pressure reductions followed by pressure increases on the exterior of the receptacle can continue until a desired configur-ation has been obtained at which time the receptacle 11 is closedby operation of the closing means 8 when its actuating means 9 are energized. However, it is preferred for the cycle to continue for only two repressurization pulses, even though the use of more than two such pulses is within the scope of such process according to the present invention.
,.
.. , ................ . _ .. _ ... _ ~9~4~2 Figure 2 i I iustrates an alternative embo~iment of the -~ apparatus in accordance with the present inventi~n, differing only in that the air admission valve 12 is connected in the 5 extraction duct 5 to the pump 6. The functional result will be the same in that the successive opening and closing of the air admission valve 12 superimposed on the continuous operation of the extraction pump 6 will achieve a pulsating pressure in the residual atmosphere around the receptacle 11 in both Figure 1 10 and Figure 2. It wil I of course be understood that the air admission valve 12 in Figure 1 need not be incorporated on the cover 2; air admission means of any suitable form could be - used, for example a valve connected to an air admission port i~
the base 3 inwardly of the position occupied by the rim 4 of the 15 cover 2 in the closed configuration of the chamber.
, ' The embodiment of Figure 2 also includes an adjust-able throttle valve 14 havin~ a control lever 13, and an adjuster 19 on the control unit 16 for selecting a different 20 pressure value at which the air admission valve 12 is to open or c lose .
Although, in Figure 1 and in Figure 2, the air admission valve 12 is operated in response to attainment of 25 particular pressure valve in the chamber 1, as indicated above, , . .. .... . . . . .. .. ..
:: :
-~, ~Z9~412 it is not essential for the control of the air admiss~on valve to be responsive to chamber pressure. For example,~ the control unit 16 may be a pulsing controller of a pneumatic type which 5 imposes pressure of suction pulses on the control line 15 to the air admission valve 12 at predetermined time intervals after commencemennt of the evacutation of the chamber 1. Alter-natively, the control unit 16 rnay not be pneumatic but may be connected So the valve 12 by a mechanical linkage or by an 10 electrical linkage, in which case the pressure- or time-responsive controller will be of a mechanical or an electrical type~ respect-ively. Yet a further possibility suitable where the receptacle is a plastic envelope is for a nnechanical feeler unit to be incorporated within the chamber 1 in order to detect when the 15 flexible envelope such as bag 11 balloons, since the ballooned state of the bag 11 at the instant of the opening of the air admission valve 12 assists the extraction operation.
Throughout the following description, the mechanism 20 f Figure 1 for use with plastics flexible bags 11 will be described in its detai led operating cycle, with reference to the cycle diagram of Figure 3 and with reference to Figures 4, 5 and 6 showing the apparatus of Figure 1 at different states in its operating cycle. It wlll of course be appreciated that the 25 different locations of the control line 15a and the sensing line . ~, ..... . ... .. . . .... .....
~29~412 .
17a in Figures 4 to 6 with respect to the posi,tions of the corresponding lines 15 and 17 in Figures 1 i5 of no functional significance but is simply to illustrate the fact that the routing of these lines is purely optional at the discretion of the machine designer.
Figure 3 shows that at the start of a typical operating cycle the pressure within the chamber is at a value Pl, normally the atmospheric pressure in the packaging room.
The machine is set up by adjusting the throttle control lever 13 to give the desired air admission rate, and also adjustiny the pressure control 19 to select a particular pressure at which the control unit 16 operates to create a signal pulse in control line 15. This pressure P2 is shown in Figure.3.
Referring now to the operating cycle depicted in Figure 3, once that chamber 1 is closed the pressure P reduces 20 from initial value P1 at point I to a value P2 which has been preset on the control 19, and at which the control unit 16 sends a signal pulse to the valve 12. As this pulse is being transmitted to the valve 12, the pressure P is till reducing below the value P2 between points ll and point lll on the 25 pressure/time curve. ~he opening of the air admission valve 12 ' ~'~9~43L~
will, howeverj result in a reduction in the rate of extraction of ~ air by the pump 6 and consequently the pressure P bottoms out at a value P3 at point lll~ and then begins to rise towards the value P2 which is attained at point IV on the curve. At this point the control unit 16 emits another signal pulse closing the air admission valve 12, but nevertheless there remains an upward swing in the pressure value towards the point V on the curve. This upward swing flattens out at point V at pressure value P~, and the pressure then begins to reduce towards point Vl on the curve. The above-described sequence of events between points ll, Ill, IV and V is repeated between points Vl, Vll, Vlll and IX. However, somewhere between points Vll ar,d IX the receptacle-closing unit 8 is operated to seal the bag 11 while the pressure around the bag is increasing and pumping out residual air from within the enverope. This is a preferred aspect of the invention and ensures optimum elimination of trapped bubbles of air or other gas from within the bag 1.
It is particularly preferable for the programmer 20 to trigger the closing action to occur between points Vlll and IX, so that the repressurization pulse on the envelope has had a chance to build up momentum.
' 25 It will readily be appreciated that the flexible bag .. . ... . . . .... . . ......
~29~4~Z
11 balloons at some stage between points I and l~l, collapses -- between points lll and V, balloons again between ~points V and Vll and collapses between points Vll and IX.
Where a particularly high vacuum (low residual pressure) is required within the bag 11, it may be envisaged that the receptacle-closing means 8 are operated between points Vl and Vll or between corresponding points on a further descending half cycle of the curve after point IX.
The process described above has been performed successfully for the packaging of cheese where a relative~y "soft" vacuum is advantageous but where the size of the cheese pack may be such that conventionally the air extraction operat-ion takes a considerable time. It has been found that the extraction time is reduced wtih such process in accordance with the present invention and the occurrence of trapped gas pockets in the pack (particularly likely in the case of Emmental cheese having cavities formed in the surface of the cheese block) is reduced. Although the present invention is not to be limited by any speculation on the functional advantages of the process, it is thought that the inward and outward oscillation of ~he wall of the receptacle (in the case of a flexible bag 11) due to the pulsating pressure on its exterior results in a pumping action .. .. . . . .. . ... . . . ..... . ., , . . , .. _, . . . . . ... . .. .
1~9~L2 which urges escape of gas (e.g. air) through the -neck of the -~ bag 1l with great momentum while the bag is sti~-i ballooned, and that this assists in persuading trapped gas pockets to 5 escape. Furthermore, this ensures that the residuai pressure right through the pack is more uniform than is possibie with prior art vacuum packaging processes.
It is envisaged that the process described wil I be 10 equally applicable to high vacuum (low residual pressure) pack-aging as to "soft vacuum" packaging (with relatively higher residual pressure values).
Figure 4 i I lustrates the condition of the apparatus 15 between points 1, ll and lll of the cycle diagram of Figure 3.
This same configuration applies between points V, Vl and Vll.
The extraction. pump 6 is in operation but the air admission valve 12 is closed.
Figure 5 illustrates the configuration between points I l l, IV and V in the cycle diagram of Figure 3. This configuration is repeated between points Vll, Vlll and IX. The air admission valve receives a signal along the signal line 15_ and opens to admit air into the chamber 1.
.
~X91~
Figure 6 illustrates the configuration at one instant ~~ during the interval between points ~111 and IX, sh~rtly before point IX, when the control unit 16 transmits a signal pulse along the signal line lSa and closes the air admission valve 12 while the receptacle-closing means 8 are actuated to seal the envelope.
The apparatus in accordance with the present invent-ion can also be used to produce a "soft vacuum" packaging whenoperated as shown in the cycle diagram of Figure 7.
At the start of such process-the pressure within the chamber is at a value P1, normally the atmospheric pressure in the packaging room. The machine is then set up as described in connection with Figures I to 6 and the pressure PCH in the chamber is reduced which~also results in a reduction of pressure PR in the receptacle. In the present process in accordance with the invention, it is not important to reach a predetermined value 2~ of pressure PCH but a sufficient pressure difference between the pressure PCH and the pressure Pp.
If a sufficient pressure difference has been generated, e.g. a pressure difference of about lSO mb for a ptastic bag as usually used for producing such packings, then -- ---..- .......
~z~
- . the .:chamber 1 wil.l be vented by opening the air adrr.ission valve 12. In the op.erating cycle depicted in Figure 7 this occurs at the time T1 and the pressure PCH in chamber 1 will increase 5 rapidly upto P1, whereas there will be no increase or almost no increase of pressure PR in the receptacle. By such increase of pressure PCH the flexible receptacle 11 is pressed inwardly against the exterior of the article 18 and the air located between the receptacle and the exterior of the article is pressed 10 out of the neck of the receptacle 11. Preferably, the extraction pump 6 is kept in operation during venting of chamber 1.
In the process described in connection with Figuré
7, generation of a high vacuum is avoided and the vacuum 15 applied shall not be larger than required to obtain the necessary pressure difference between pressure PCH and pressure PR. Therefore, removal of air from~ the interior of article 18 is minimized whereas the air located between the exterior of article 18 and receptacle 11 is effectively removed.
As it is preferre?d to suddenly press- inwardly the receptacle 11 against the exterior of the article 18 to rernove the air located between the receptacle 11 and the ex~erior of the article 18, the apparatus shown in Figures 1 and 2 and 4 to 6 25 would not require a throttle 14 but venting of chamber 1 shoutd : , , ~'~91~Z
be effected in such a way tha~ increase of pressure PCH is_ -- obtained within the shortest time possible, i.e. t-he pressure curve PCH shown in Figure 7 shall have a very high steepness 5 starti ng at T1 immediately after the receptacle 11 has been pressed against the exterior of the article 18 which s~ep has been completed at time T2 in the operation circle depicted in Figure 10 7~ the receptacle 11 wil I be closed by means of the receptacle-closing means 8. Such closing will take place not later than 0.5 seconds after the time T2 of Figure 7 since otherwise air from chamber 1 might enter the neck portion of receptacle 11.
If desired, the sealed receptacle 11 may be subject-ed to a shrinking operation to cause the receptacle material to contact the article 18 intimately.
Although it is envisaged that the apparatus in accordance with the present invention may be equipped from the outset with repressurization means such as the air admission valve 12, it is also within the scope of the present invention for an ex7sting vacuum chamber machine to be modified, simply by the addition of repressurization means such as the air admission valve 12 (and suitable control means therefor) either on the ~L2~
chamber 1 or on the extraction conduit 5, so as t~ modify that - existing machine to operate in accordance with the~-processes of the present invention.
.
Although, in the above description, the envelope-closing means 8 comprises a heat sealing bar arrangement, other suitable closing mechanisms may be provided, For exarnple radiant heat fusion sealing means operating in conjuction with 10 the yieldable holding means 21 to allow escape of air from within the receptacle 11 before the emission of a radiant heat pulse to cause the receptacle to fuse upon pressing contact with itself by the increasing pressure in the chamber 1 between points Vl I and IX of Figure 3 or between T2 and T3 In Figure 7.
1~ :
Other closing systems such as a gathering and clipping mechanism may instead be provided. Likew7se, although the apparatus i I lustrated in Figures 1, 2, 4, 5 and 6 shows a single, open chamber, it is of course possible ~or the processes zO of the present invention to be carried ou~ using the "in-chamber nozzle" disclosed in the above mentioned U.S. Patent No. 3 714 754 (Holcombe), or in the double chamber construction disclosed in the above mentioned U.S. Patent No. 3 B32 824 (Burrel I ) .
As mentioned above, the operation of the air .. : . ,, .,, .. ,, .. , ,. , ., . , . . . . .. , .. . _ _ ... .. ... . . . . .
L4~
admission valve 12 may be controlled simply on the basis of time -~ elapsed since the start of the cycle, or in response-to operation of a mechanical feeler, and both of these control mechanisms can 5 be incorporated as modifications to existing vacuum chamber packaging equipment.
. , , . . . .. . .. .... .. _ .. _ ... . . ..... .... . . .
Claims (20)
1. A process for vacuum packaging an article in a flexible receptacle, comprising loading the article in the receptacle, extracting gas from around the exterior of the receptacle to lower the surrounding pressure, extracting gas from within the recep-tacle, and closing the receptacle in a gas-tight manner after the extraction of gas from its interior, characterized in that after the pressure surrounding the receptacle has been initially lowered, that pressure is raised in a pressure restoration phase, before the receptacle is closed, said pressure restoration phase being started at a predetermined pressure difference between the pres-sure surrounding.the receptacle and the pressure within the receptacle, the closing of the receptacle being carried out immediately after the receptacle has been pressed against the exterior of the article, and after said pressure restoration phase the pressure surrounding the receptacle is lowered in a further pressure reduction step before the receptacle is closed.
2. A process according to claim 1, characterized in that there are only two phases during which pressure is restored sur-rounding the exterior of the receptacle, these pressure restoration phases being separated by a pressure reduction step in which gas is extracted from the exterior of the receptacle, and the recep-tacle being closed during the second of said pressure restoration phases.
3. A process according to claim 1, characterized in that the loaded receptacle is placed in a vacuum chamber and the closing of the receptacle is also carried out within the vacuum chamber.
4. A process according to claim 3, wherein the vacuum chamber is connected to an extraction pump, characterized in that the restoration of gas to the exterior of the receptacle is carried out by opening a valve which allows gas to enter the chamber at a rate which is greater than the rate of extraction by the extraction pump.
5. A process according to claim 4, characterized in that the extraction pump operates continuously and the venting valve, which opens while the gas extraction pump is in operation, is cap-able of introducing gas into the chamber at a rate faster than the rate of extraction by the extraction pump.
6. A process according to claim 1, 2 or 3, characterized in that the receptacle is a flexible envelope which balloons away from the article during said pressure reduction step and becomes pressed down against the product article during said gas pressure restoration phase.
7. A process according to claim 1, 2 or 3, characterized in that the receptacle is yieldably held closed during the gas extraction and gas restoration periods, to allow escape of air from, but to impede re-entry of air into, the receptacle.
8. Apparatus for vacuum packaging, comprising a vacuum chamber having an extraction pump for extracting gas from within the interior of the chamber and a support for a loaded flexible receptacle to be evacuated and sealed in the chamber; and means for closing the receptacle in the chamber; characterized by means for restoring pressure to the exterior of the receptacle disposed within the vacuum chamber after partial evacuation of the chamber by the extraction pump before the receptacle is closed, program-ming means being provided to ensure further pressure reduction in the chamber after operation of the pressure restoration means.
9. Apparatus according to claim 8, characterized by a pro-grammer ensures that the pressure restoration means carry out at least two pressure restoration phases separated by a pressure re-duction step during which gas is extracted from within the chamber by the extraction pump.
10. Apparatus according to claim 9, characterized in that said pressure restoration means comprises a gas admission valve connected to the space evacuated by the extraction pump.
11. Apparatus according to claim 10, characterized in that said gas admission valve is connected to a wall of the vacuum chamber.
12. Apparatus according to claim 10, characterized in that the valve is connected to an extraction duct between the vacuum chamber and the extraction pump.
13. Apparatus according to claim 10, 11 or 12, characterized in that said gas admission valve includes a variable throttle valve for adjusting the rate of admission of gas to the chamber.
14. Apparatus according to claim 10, characterized in that said gas admission valve is controlled in response to the vacuum level in the vacuum chamber by a control unit and a vacuum sensing line.
15. Apparatus according to claim 14, characterized in that said vacuum level-responsive control unit includes means for selecting a particular vacuum level at which the control unit sends a signal to open or close the gas admission valve.
16. Apparatus according to claim 10, 11 or 12, characterized in that the gas admission valve is controlled by a timer according to a predetermined programme of gas admission phases when the valve is open and pressure reduction steps when the valve is closed and the extraction pump is in operation.
17. Apparatus according to claim 10, 11 or 12, characterized in that the programmer is effective to open and close the admission valve according to a predetermined programme, to maintain oper-ation of the extraction pump during gas extraction phases and gas restoration phases, and to operate the bag closing means during a pressure restoration phase while the gas admission valve is open.
18. Apparatus according to claim 8, 9 or 10, characterized in that the bag closing means comprises opposed heat sealing bars which, for bag closing, are driven together and energized elec-trically to impart sealing heat to clamped wall portions of the receptacle.
19. Apparatus according to claim 8, characterized by yield-able holding means for holding the receptacle substantially closed while allowing air to vent from the interior of the receptacle.
20. Apparatus according to claim 19, characterized in that the yieldable holding means includes an elastic blade and an anvil to hold a portion of the receptacle therebetween.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT24538A/81 | 1981-10-16 | ||
| IT24538/81A IT1139239B (en) | 1981-10-16 | 1981-10-16 | VACUUM PACKAGING EQUIPMENT AND PROCEDURE |
| EP82108140A EP0077458B1 (en) | 1981-10-16 | 1982-09-03 | Vacuum packaging apparatus and process |
| EP82108140.3 | 1982-09-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1291412C true CA1291412C (en) | 1991-10-29 |
Family
ID=26084275
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000413519A Expired - Lifetime CA1291412C (en) | 1981-10-16 | 1982-10-15 | Vacuum packaging apparatus and process |
Country Status (9)
| Country | Link |
|---|---|
| AR (1) | AR228686A1 (en) |
| AT (1) | ATE17213T1 (en) |
| AU (1) | AU549772B2 (en) |
| CA (1) | CA1291412C (en) |
| DK (1) | DK456382A (en) |
| FI (1) | FI72474C (en) |
| IE (1) | IE53415B1 (en) |
| NO (1) | NO156562C (en) |
| NZ (1) | NZ202174A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1989001440A1 (en) * | 1987-08-18 | 1989-02-23 | Alfa-Laval Engineering Pty. Limited | Improved vacuum packaging technique and devices |
-
1982
- 1982-09-03 AT AT82108140T patent/ATE17213T1/en not_active IP Right Cessation
- 1982-09-21 IE IE229282A patent/IE53415B1/en unknown
- 1982-10-14 FI FI823503A patent/FI72474C/en not_active IP Right Cessation
- 1982-10-14 AU AU89366/82A patent/AU549772B2/en not_active Ceased
- 1982-10-14 NZ NZ20217482A patent/NZ202174A/en unknown
- 1982-10-14 NO NO823431A patent/NO156562C/en unknown
- 1982-10-14 DK DK456382A patent/DK456382A/en not_active Application Discontinuation
- 1982-10-14 AR AR29096682A patent/AR228686A1/en active
- 1982-10-15 CA CA000413519A patent/CA1291412C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| FI823503A0 (en) | 1982-10-14 |
| AU549772B2 (en) | 1986-02-13 |
| FI823503L (en) | 1983-04-17 |
| DK456382A (en) | 1983-04-17 |
| FI72474B (en) | 1987-02-27 |
| NO156562B (en) | 1987-07-06 |
| IE822292L (en) | 1984-03-03 |
| IE53415B1 (en) | 1988-11-09 |
| FI72474C (en) | 1987-06-08 |
| AR228686A1 (en) | 1983-03-30 |
| NO823431L (en) | 1983-04-18 |
| AU8936682A (en) | 1983-04-21 |
| NO156562C (en) | 1987-10-14 |
| NZ202174A (en) | 1986-05-09 |
| ATE17213T1 (en) | 1986-01-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0077458B1 (en) | Vacuum packaging apparatus and process | |
| US4583347A (en) | Vacuum packaging apparatus and process | |
| US4471599A (en) | Packaging process and apparatus | |
| CA1073796A (en) | Vacuum-packing method and apparatus | |
| EP0309132B1 (en) | Packaging method and apparatus | |
| US4379743A (en) | Sputtering apparatus comprising control means for preventing impurity gases from entering a sputtering chamber | |
| GB2104472A (en) | Vacuum packaging in a heat shrinkable thermoplastic bag | |
| DK142491B (en) | Method and apparatus for vacuum packaging a product in a flexible container. | |
| EP0167688A1 (en) | Air extractor for a bag making/filling/packaging machine | |
| CA1291412C (en) | Vacuum packaging apparatus and process | |
| US2888792A (en) | Vacuum sealing machine | |
| EP0541183B1 (en) | Method and apparatus for making a filled and closed vacuum pack | |
| JPH10236428A (en) | Vacuum packaging device | |
| GB2078658A (en) | Vacuum packaging process and apparatus | |
| IE52224B1 (en) | Packaging process and apparatus | |
| JP3406172B2 (en) | Vacuum packaging machine | |
| EP1564147A1 (en) | Vacuum packaging apparatus and process | |
| JPH0958613A (en) | Vacuum packaging method for processed food and its device | |
| JPH07156914A (en) | Vacuum pressure control method of vacuum packer | |
| JP2784855B2 (en) | Vacuum packaging equipment | |
| SU1443792A3 (en) | Apparatus for packing products into thermoplastic bag in vacuum | |
| JPH0455071A (en) | Partial vacuum type fully automatic electron beam welding device and method therefor | |
| JPH0646308Y2 (en) | Anaerobic treatment device for fresh tea leaves | |
| KR100744880B1 (en) | Packaging method and device | |
| JPH10119923A (en) | Vacuum packaging device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |