Package making – Methods – With contents treating
Reexamination Certificate
2001-03-06
2003-04-08
Gerrity, Stephen F. (Department: 3721)
Package making
Methods
With contents treating
C053S512000, C053S437000, C053S525000, C053S469000, C053S284700, C053S480000, C053S370600
Reexamination Certificate
active
06543206
ABSTRACT:
This invention relates to the formation of sealed packages, more particularly sealed packages containing a charge of a flowable product, for example a comminuted product, such as roasted and ground coffee, and formed from a sealable material.
Comminuted products, such as roasted and ground coffee, tea or instant coffee, are often sold in tins or in packages in the form of sealed bags made of a sealable plastics material. Such a sealable material may be heat sealable or pressure sensitive material (or a so-called cold seal material). The sealable material may include a barrier layer of aluminium foil. In some countries the product is generally packed in such sealed bags at atmospheric pressure; in others it is more usual for the product to be packed under vacuum so that the packaging material conforms closely to the product. This has the benefit that the product is protected from the effects of oxygen and the environment and also that the package, which typically has a rectangular parallelepipedal shape somewhat similar to a brick, takes up less space than a package that has been packed at atmospheric pressure.
Currently used technology involves placing the filled bags in turn into a bell chamber followed by evacuating the chamber and the bag before sealing the top of the bag within the bell chamber. This arrangement typically requires 12 seconds and 30 kW of pump power for bags containing 250 g to 1000 g (e.g. 500 g) of roast and ground coffee in order to evacuate the bags at a rate of 100 bags per minute. Hence the system is relatively slow and has high energy requirements.
Other flowable materials which can be mentioned include sugar, flour, potato crisps, rice grains or flakes, and the like and liquids such as paint and soup.
FR-A-2560857 teaches a machine for filling sealed coffee bags which has a turntable with a drive underneath. Chambers around the periphery of the turntable each contain a vertically supported filled coffee bag. Each chamber is connected to a tube partly under the turntable. A throttling valve arrangement is provided with a channel which ends at a vertical tube communicating with a vacuum pump and to the atmosphere. A valve member is rotated by a radial arm which has a head that is held by a spring against a cam track acting as the turntable rotates. Connection with vacuum and with the atmosphere is achieved by means of a control disc, having a ring of holes, and slots. This arrangement is said to prevent escape of coffee powder.
In U.S. Pat. No. 4,730,439 there is disclosed a method of formation of vacuum sealed packets. In this method open topped packets are formed and filled, whereupon a vacuum tube is inserted in the top of the packet and then the side walls are urged around the vacuum tube in order to cause a temporary vacuum in the packet while the side walls are sealed together below the vacuum tube.
Use of a vacuum packer is described in FR-A-2488215; this nearly seals the packages by welding along the top edge or a side as air is drawn out by a probe which is extracted before final sealing. Sealing is effected by moving the package across a fixed welding head. The probe can be progressively retracted after the beginning of evacuation and before the final closure welding.
In GB-A-1474838 there is described an apparatus for evacuating a fluid from an open-ended flexible, thermosealable bag which comprises a bag holding member arranged to be inserted into the open end of the bag and to fit snugly against the inner surfaces thereof. This member has a plurality of openings in it connected to a vacuum source. A probe with a passage connected to a vacuum source is supported by the member and can be extended into and retracted from the bag. Sealing is effected after the probe is withdrawn from the bag.
GB-A-1416101 teaches use of a suction pipe for sucking gas out of a container containing a pulverulent or granular material. This pipe has a free end with a plurality of apertures separated by elastically deformable tongues effective to close the free end of the pipe by mutual engagement.
U.S. Pat. No. 3,796,020 discloses a hand operated machine for evacuating and sealing a bag.
In U.S. Pat. No. 3,589,098 an arrangement of cams is used to move a bag-evacuating nozzle, to move a pressure bar for applying pressure to the bag, to vary the length of the heater period, and to control the length of the sealing period.
GB-A-1199580 shows use of a hollow needle to evacuate a bag; this needle is then withdrawn before sealing bars close to seal the bag and a knife severs the evacuated bag.
U.S. Pat. No. 2,634,562 and its divisional, U.S. Pat. No. 2,692,074 teach a hand operated machine in which packages are sealed except at an ear. The plies of the bag are held apart by applying vacuum to the outer surfaces and provide an opening through which the package can be evacuated before it is finally sealed.
A bag evacuating and closing apparatus with two opposed jaws which encompass a top closure of a bag to be sealed and which have hollow spaces is taught in U.S. Pat. No. 5,097,648. A sealing rib protrudes from one face end of one of two frames which surround the jaws. This sealing rib is interrupted in a middle region of the frame part at which the closure fold protrudes between the jaws. Suction openings in this region allow the walls of the top closure to be pulled tightly against the frame parts, whereupon air is sucked out of the bag which is then sealed by the sealing jaws.
A method and apparatus for producing a vacuum package filled with granular material are described in EP-A-0626312. A package filled with granular product is compressed by applying pressure to the side walls of the package so that the granular product forms a compact whole. Then the compressed package is evacuated through a small suction opening by means of a vacuum element comprising a needle. Thereafter the package is sealed with the aid of a separate sealing strip, which is placed inside the bag before filling, by pressing a heated sealing jaw against the wall in the region of the sealing strip, the compressed granular material providing support during this step for the sealing strip.
EP-A-0634324 discloses an apparatus for filling with an inert gas the head space of a tub which is closed by a lid.
In EP-A-0685391 there is disclosed a machine for forming-filling packaging bags, with provision for evacuating the filled bags, in the form of a sealed or tight bell.
For the sake of appearance it is desirable that, when the flowable material is a comminuted material such as roasted and ground coffee, the sealed package shall have as regular a shape as possible, most usually in the shape of a rectangular parallelepiped. It is, however, difficult to achieve reliably a truly rectangular parallelepipedal shape. This is because the packaging material tends to crinkle as the air is drawn out of the package and as the packaging material conforms to the outside of the parallelepipedal brick of coffee or other comminuted product. In addition there is the problem that, if any of the comminuted product is disturbed significantly during the evacuation step, it can become displaced into the seal area and result in formation of a faulty seal. There is also a danger that the roasted and ground coffee or other comminuted product can get drawn into the vacuum system.
Prior art methods and apparatus for forming sealed evacuated packages of comminuted products such as coffee are relatively slow in operation. However, although higher speeds are theoretically possible by enlarging the machinery, the size of the resulting machines becomes unmanageable for machines capable of operating at speeds above about 150 bags per minute.
It would be desirable to provide an apparatus for forming evacuated packages of flowable products, such as comminuted products, which is capable of operating reliably at significantly higher operating speeds than the current practical limit of about 150 bags per minute.
Accordingly there is a need in the art for a novel method, and an apparatus for use of such a method, of evacuating and sealing
Cahill Michael John
Hinkley Adrian Mark
Mitchell Roderick Leslie
Seward David Robert
Gerrity Stephen F.
Jensen & Puntigam P.S.
Molins Plc
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