EP3560844A1 - Packaging machine with heated grid - Google Patents

Abstract

Packaging machine (1) for packaging products under vacuum, the packaging machine (1) comprising a lid (3) and a chamber base (5), which together form a chamber (7), a suction opening which can be closed in a gas-tight manner in the chamber base (5) (9) is formed, with which a suction device (37) for evacuating the chamber (7) is connected. An electrically heated grid (11) is arranged on the suction opening (9) in order to prevent the suction opening (9) from icing up when the chamber (7) is evacuated.

Description

The present invention relates to a packaging machine for packaging products under vacuum.

Products, especially food products, are often vacuum packaged to increase shelf life and product presentation benefits. For this purpose, packaging machines are used which evacuate a product packaging with a product therein and then seal. For this purpose, a vacuum is generated in an otherwise gas-tight sealed chamber by the air is sucked out of the chamber by means of a suction device. In this case, a suitably formed in the chamber bottom suction opening serves as an air outlet. The packaging machine may be designed as a single device, into which the product packaging is manually inserted, or as part of an automated production line, in which the product packaging is transported by means of a conveyor belt into the packaging machine. Such a packaging machine is from the EP 2 110 321 B1 known.

A disadvantage of such packaging machines is that when sucking the air from the chamber at the suction due to the cross-sectional constriction to a local increase in the flow rate and thus a decrease in the static pressure with simultaneous decrease in temperature. This effect often leads to icing of the suction opening.

The object of the invention is to provide a packaging machine in which an operation of the machine is improved.

This object is achieved by a packaging machine with the features of claim 1. Advantageous developments of the invention are specified in the dependent claims.

A packaging machine according to the invention for packaging products under vacuum comprises a lid and a chamber bottom, which together form a chamber, wherein in the chamber bottom a gas-tight closable suction opening is formed, with which a suction device for evacuating the chamber is connected. "At" the suction opening (ie in the region of the suction opening), an electrically heatable grid is arranged to heat the suction opening when evacuating the chamber. Thus, despite the cooling effect described above, there is no formation of ice on the suction opening. This prevents further constriction of the suction opening due to adhering ice. Also remains a closing of the Suction through a valve-like element of the suction device, as described in the cited prior art, further possible. In addition, damage to the suction device, in particular a vacuum pump, is prevented by dissolving ice.

Preferably, the grid is arranged in or above the suction opening. Thus, the heat radiation of the grid can heat the edges of the suction opening, which also contributes to the desired effect, namely the prevention of ice formation.

In an advantageous variant, the grid is mounted on an electrically insulating frame. Since the grid itself flows through current and is usually not covered with insulation, it can still be mounted on the chamber bottom or the edges of the suction opening. The chamber floor, in which the suction opening is formed, is usually made of a metal, for example stainless steel, for reasons of hygiene and stability. By mounting the grid on an electrically insulating frame no conductive connection between the grid and the chamber floor is present and thus precludes an impairment of other electronic components of the packaging machine or an operator by electric current.

Ideally, the frame is substantially flush with the bottom of the chamber and completely surrounds the suction opening, so that all evacuated air flows through the grid. Thus, the device exhibits its greatest possible efficiency, since only air reaches the suction opening, which has flowed through the heated grid.

In a common variant, the grid is fixed at a first and a second end with projecting through the chamber bottom, vacuum-sealed built pins. The contact pins serve to mechanically fix the grid and the insulating frame on the chamber floor, so that all three components lie flush against each other and an air passage between the surfaces with which they are prevented from each other. The attachment can be done via screw, wherein the grid and the insulating frame each have holes or recesses can be inserted through a screw and then screwed with an internal thread in the contact pin. So the connection is also solvable again and the components can be replaced if necessary.

In a typical variant, a power supply for supplying the grid with about 80 to 800 watts of electrical power, preferably 400 to 600 watts, provided. Due to the size and geometry of the grid, there is sufficient electrical power available for this To resist the resistance of the grid. Thus, sufficient electrical current also flows through the lateral regions from the first to the second end of the grid.

In an expedient variant, the contact pins make an electrical connection of the grid with the power supply, wherein the contact pins are electrically insulated from the bottom of the chamber. For this purpose, the contact pins, for example, a core of electrically conductive material and a sheath of electrically insulating material. Thus, the current can be passed through the bottom of the chamber to the grid without electricity being transferred to the bottom of the chamber.

In a preferred variant, the power supply has a regularly recurring duty cycle of approximately 0.5 to 1.5 s. Thus, the required heating power is available within a short time and it is sufficient to turn on the power supply of the grid only just this time before the evacuation process and meanwhile. After completion of the evacuation, the power can be switched off again. Thus, the power consumption is limited to the necessary minimum, but does not affect the cycle times of the packaging machine.

Typically, the grid is made of an electrically conductive and approved for the food industry material, especially stainless steel. Due to its conductivity, the material is therefore suitable for resistance heating, but does not release any substances to the environment as a result of the heating. Thus, an impairment of the products to be packaged is excluded.

In a further variant, the grid has a length of about 50 to 120 mm and a width of about 20 to 80 mm. In this case, the lattice dimensions primarily depend on the size of the suction opening and, if necessary, slightly exceed it in order to completely span the suction opening. The grid and the insulating frame may, for example, have a substantially rectangular shape with a longer and a shorter side. To energize the grid evenly, the contact pins are usually arranged on the short sides. Thus, due to the resistance being generated, the current flows almost equally through all the lattice struts from the first to the second, short side of the lattice.

In a conventional variant, the grid has webs which in particular have a width and a height of about 0.5 to 1.5 mm. The dimensions of the webs are chosen so that they experience a heating due to their resistance with the best possible efficiency when applying a suitable electrical voltage.

In a favorable variant, the webs at a distance of about 8 to 10 mm from each other. This ensures that the air flow through the suction opening is not reduced by the grid.

In a further typical variant, the packaging machine is a chamber belt machine. It is thus part of an automated production line and the product packages to be evacuated are conveyed by means of a conveyor belt to the chamber to be evacuated and sealed there. This allows high cycle times without manual intervention and thus high product output.

Figur 1:

eine perspektivische Ansicht einer Verpackungsmaschine in Form einer Kammerbandmaschine,

Figur 2:

eine perspektivische Ansicht eines beheizbaren Gitters auf einem isolierenden Rahmen fixiert durch zwei Kontaktstifte,

Figur 3:

eine perspektivische Ansicht eines Schnitts durch eine Absaugöffnung mit beheizbarem Gitter und Teil einer Absaugvorrichtung.

Embodiments of the invention will be described in more detail below with reference to the figures. Show

FIG. 1:

a perspective view of a packaging machine in the form of a chamber belt machine,

FIG. 2:

a perspective view of a heatable grid on an insulating frame fixed by two pins,

FIG. 3:

a perspective view of a section through a suction opening with a heated grid and part of a suction device.

Corresponding components are each provided with the same reference numerals in the figures.

FIG. 1 shows a packaging machine 1 in the form of a chamber belt machine with a vertically displaceable lid 3 and a chamber bottom 5. If the lid 3 is lowered onto the chamber bottom 5, a chamber 7 is formed, which closes gas-tight between the lid 3 and chamber bottom 5. In this example, two suction openings 9 are formed in the chamber bottom 5, above each of which a heatable grid 11 is arranged. About the suction openings 9, the chamber 7 is evacuated. The product packages to be evacuated are transported on a conveyor belt 13 into the chamber 7. The ends of a product packaging can be guided over a sealing strip 15 so that the product packaging can be permanently closed by forming a vacuum in the chamber 7 by a heat seal.

FIG. 2 shows the heatable grid 11, which is arranged on an insulating frame 17. The grid 11 has webs 19, which extend in the longitudinal and transverse directions. According to the dimensions described above, the grid 11 has a length L and a width B. The webs 19 have a height H, a width B1 and a distance A from each other. At the substantially rectangularly shaped grid 11, a first and a second solid end 21, 23 are formed in a triangular shape. The two ends 21, 23 are each screwed by means of a screw 25 to the frame 17 and a respective contact pin 27. By means of a respective nut 29, the contact pins 27 are clamped against the chamber bottom 7, so that the frame 17 rests flush on the chamber bottom 7. Spacers 31 are used to adapt to different thicknesses chamber bottoms 5. As can be seen, the frame 17 has on its short sides a massively formed first and second ends 33, 35. As a result, a stable screw connection with the contact pins 27 is ensured. On its long sides, however, the grid 11 rests only on a relatively narrow side wall of the frame 17.

The first and second ends 33, 35 of the insulating frame 17 each have at their top a bevel, which makes it possible to mount the contact pins 27 with a corresponding inclination. Matching the slope of the first and second ends 22, 35 of the insulating frame 17, the first and second ends 21, 23 of the grid 11 are bent upwards. Thus, as in FIG. 3 shown, the contact pins 27 for mounting, for example, the tightening of the nuts 29, also adjacent to a suction well accessible.

FIG. 3 shows a section through the suction opening 9 arranged thereon with heatable grid 11 and a part of a suction device 37. The grid 11 is mounted on the frame 17 and thus electrically insulated from the chamber bottom 5. At the same time the frame 17 is flush with the chamber bottom 5, so that only air which has flowed through the grid 11 and thus was heated, reaches the suction opening 9. The contact pins 27 have an electrically conductive inner part 39 and an inner part 39 surrounding insulation 41. In the inner part 37, a bore 43 is provided with an internal thread into which the screw 25 is screwed to connect the grid 11 and the frame 17 with the contact pin 27.

In the chamber bottom 5 holes or recess are provided, through which the contact pins 27 are performed. On the outer or lower side of the chamber bottom 5 of the contact pin 27 is clamped by means of the nut 29. The vacuum tightness at the implementation of the contact pins 27 is ensured by the contact pins 27 surrounding seals 50.

With the electrically conductive inner part 39 expediently power supply lines 45 are connected, for example by soldering, welding or screwing. A power supply 47, for example a transformer, provides the required electrical energy The suction device 37 comprises an air channel 49 through which the air is sucked out of the chamber 5 by means of a vacuum pump (not shown). For gas-tight closing of the suction opening 9, a piston 53 is arranged in a cylinder-like guide 51, which can be moved up and down and closes the suction opening 9 accurately in an uppermost position.

Starting from the embodiments of a packaging machine 1 shown above, many variations of the same are conceivable. Thus, for example, the grid 11 and the frame 17 can be extended in their longitudinal extent, so that the contact pins 17 can be oriented substantially perpendicular to the chamber bottom 5 and the assembly, in particular the tightening of the nuts 29, nevertheless possible. Thus, an inclination of the first and second ends 21, 23 of the grid 11 and the first and second ends 33, 35 of the frame 17 can be dispensed with. At the same time, the first and second ends 21, 23 of the grid 11 and the first and second ends 33, 35 of the frame 17, ie the solid sections, could be increased accordingly so that the area of the grid 11 through which the air flows remains unchanged in size. Although it is advantageous, as explained in the cited prior art, to arrange the suction openings 9 in the chamber bottom 5, it is also possible, the suction openings 9 at other suitable locations of the chamber 7, for example at the top or side surfaces of the lid. 3 to train. Further modifications to the structure of the packaging machine 1 per se are further possible in many ways. Thus, for example, the lid 3 may be hinged to a hinge on the chamber bottom 5 and a frame of the packaging machine 1 and opened and closed by opening and closing instead of by a vertical displacement. Furthermore, in the sense of the invention, instead of intersecting ridges 19, the lattice 11 can also have these in a different orientation to one another, for example parallel along only one direction. In addition, the webs 19 can be completely dispensed with, so that the grid 11, preferably in dependence on the shape of the suction opening 9, is essentially a resistance-heated frame or ring, which in particular heats the edge of the suction opening 9, so that ice formation is prevented there ,

Claims (13)

Packaging machine (1) for packaging products under vacuum, the packaging machine (1) comprising a lid (3) and a chamber bottom (5), which together form a chamber (7), wherein in the chamber bottom (5) a gas-tight closable suction opening (9) is formed, with which a suction device (37) for evacuating the chamber (7) is connected, characterized in that at the suction opening (9) an electrically heatable grid (11) is arranged. Packaging machine according to claim 1, characterized in that the grid (11) is arranged in or above the suction opening (9). Packaging machine according to one of the preceding claims, characterized in that the grid (11) is mounted on an electrically insulating frame (17). Packaging machine according to claim 3, characterized in that the frame (17) rests substantially flush on the chamber bottom (5) and the suction opening (9) completely surrounds, so that during evacuation all extracted air flows through the grid (11). Packaging machine according to one of the preceding claims, characterized in that the grid (11) at a first and a second end (21, 23) with the chamber bottom (5) projecting, vacuum-tightly installed contact pins (27) is fixed. Packaging machine according to one of the preceding claims, characterized in that a power supply (47) for supplying the grid (11) with about 80 to 800 watts of electrical power is provided, preferably 400 to 600 watts. Packaging machine according to claims 5 and 6, characterized in that the contact pins (27) produce an electrical connection of the grid (11) with the power supply (47), wherein the contact pins (27) against the chamber bottom (5) are electrically insulated. Packaging machine according to claim 6 or 7, characterized in that the power supply (47) has a duty cycle of about 0.5 to 1.5 s. Packaging machine according to one of the preceding claims, characterized in that the grid (11) is made of an electrically conductive and approved for the food industry material, in particular stainless steel. Packaging machine according to one of the preceding claims, characterized in that the grid (11) has a length (L) of about 50 to 120 mm and a width (B) of about 20 to 80 mm. Packaging machine according to one of the preceding claims, characterized in that the grid (11) has webs (19) which in particular have a width (B1) and a height (H) of about 0.5 to 1.5 mm. Packaging machine according to claim 11, characterized in that the webs (19) have a distance (A) of about 8 to 10 mm from each other. Packaging machine according to one of the preceding claims, characterized in that the packaging machine (1) is a chamber belt machine.

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