DE2117458A1 - Bell-oven heating by radiation and - convection - Google Patents

Abstract

The work pieces, e.g. thermoplastic films, are charged to an inverted bell ooven via its lower access port. The pieces are heated by radiation and convection from heaters placed round the port periphery. The port is the only open secton of the oven and ensures minimal heat losses during charging operations and also even thermal characteristics throughout the heating zone with a capacity for heating during off-load conditions.

Description

Title: Oven bell, heated by radiation (technical name) and convection heat Field of application: The present invention mainly serves The shrinkage of plastic films is now used for closing and packaging Objects, especially from pallet loads.

State of the art: There are currently two different types of devices for palletizing in this way: 1. Convection ovens with doors on two opposite sides Sides that open the ovens to their full width on the one hand, na the processed load to let out, on the other hand, to let in a new charge.

The doors are open for around 50% of working hours, which is considerable Results in energy losses.

The hot air supply of these ovens takes place in two different ways : = vertical hot air supply blowing from top to bottom, which is detrimental to The result is that the top of the load is exposed to an excessive temperature and there is too little shrinkage at the height of the pallet, i.e. exactly the most essential point, since the goal of the whole shrinking process is the To connect the load as perfectly as possible to the pallet.

The vertical supply of hot air is only blowing from the bottom up Very little used because the hot air is between the load and the packaging material is blown, which is very disruptive to the process.

- horizontal hot air supply: this has a poor distribution the warm air on the sides formed by the doors. Around to compensate for this disadvantage, the furnace is enlarged.

In addition, the hot air must be kept at the high temperature at all times that is necessary to trigger the shrinking effect. Towards the end of the process however, this high temperature often causes the film to tear because of the melting point is reached.

2. Systems based on infrared radiation. The job performance is very different, depending on the nature of the foil to be scraped. Different Materials have steep absorption coefficients when exposed to radiation Wavelength. In addition, the convection losses are right with certain radiators significant, which affects the fertility significantly.

Task: The present invention seeks the advantages of both methods use, i.e. even shrinkage of the film on all five sides of the load and above all at the level of the pallet, making optimal use of the available Achieve standing thermal energy.

Solution: The system consists of a cuboid, bee-healed housing, The four vertical sides closed on the four vertical sides and the (2) upper side Inner walls are clad with metal elements (4) which are used to store heat to serve. These four vertical sides are extended downwards by fields (i), which radiator elements accommodate. These elements are arranged so that a part the released energy can be used as convection heat. The dimensions this annex, ii hereinafter called .GlockeN, are according to the size of the charge which should be processed and which should be completely enclosed by the cuboid must be chosen.

The bell can be moved vertically to allow the removal of the the processed load and the introduction of (3) the new load. A Fixed frame is used to accommodate the mechanical and electrical elements and to guide the bell (5) when moving up and down. By an electric Control cabinet is programming the necessary movements and the regulation the performance of the radiator element. The charges move by a conveyor system, which is based on the work cycle of the Bell is set. (Not included in the drawing) Working method: Because the radiator elements use part of their energy as convection heat release, the air stored in the bell is used very quickly for the work process brought the necessary temperature and used the interior cladding as a heat store. These Cladding is corrugated and separated from the heat source by convection to allow from both sides. The bell goes down during an operation and the hot air squeezed out from the volume of the cargo is evacuated, taking it smeared the sides of the load evenly. Is the bell in the lowest Once in position, convection currents build up between the hot inner lining the bell and the cold surface of the foil surrounding the charge. The air temperature quickly falls below the melting point of the film, which prevents any tearing However, by regulating the energy emitted on the basis necessary for the shrinking process Level held. The radiators lead the convection currents enough new energy to and act through radiant heat exclusively in the amount of the pallet, whereby this is where the greatest possible shrinkage is achieved.

After a predetermined time, the bell moves up so that the Charge removed and a new charge introduced.

During this dead time, the radiators continue to heat in order to generate more heat to store in the interior cladding and the air contained in the bell again to heat up.

The principle of the mixed use of radiation and convection waves in a housing that is only open at the bottom can be used in various ways will. When working on small objects, the bell itself could fixed and the objects could be underneath by a vertical conveyor system the bell to be brought.

Application area The most important application area is palletizing be a new form of packaging and distribution of consumer and capital goods.

This technique makes it possible to reduce the costs of transport, maintenance and Significantly lower storage.

patent claim: system that heats bodies evenly has to the subject with the main application of the shrinking of thermoshrinkable Plastic films for @ leasing and holding loads on pallets, characterized by the mixed effect of the radiation and tonvection energy and by the sole opening at the bottom, which prevents thermal losses and thermal charging made possible during the dead times.

Characteristic part Housing open on the lower side only, the lower land of the housing equipped with heating elements, velche by radiation and Convection heat work.

Abstract: Oven bell, heated by radiant and convection heat.

Facility that undergoes thermal treatment on five sides of a three-dimensional Object made possible by infrared radiation and convection heat.

Claims (1)

The system consists of a ring that holds the radiator elements. This ring has a heat-storing housing that is only open at the bottom.