SU1574508A1 - Thermal shrinkage furnace - Google Patents

Abstract

The invention relates to a packaging technique, in particular to heating furnaces for heat shrinking of a film, and can be used for packaging shrink film of weights having dimensions from 600 ^{. 400.} 400 to ^{1200. 1000.} 1000 mm. The aim of the invention is to reduce energy consumption. The heat-shrinkable furnace contains a heat-insulating chamber 1, in which along the sides there are centrifugal fans 3, blocks of heating elements 2 and guide plates separated from the working zone of chamber 1 by covers 6 with openings 7. The guide plates are arranged in pairs and perpendicular to the covers 6 and the side walls of the chamber 1, at an angle to one another and form channels. In the lower part of the chamber 1, a conveyor 9 passes, at the level of the cargo branch of which nozzles 8 are attached to the openings 7 of the casing 6. 8. 1 z. P. f-ly, 3 ill.

Description

The invention relates to packaging technology, in particular to heating furnaces for heat shrinking of a film, and can be used for shrink wrapping of weights having dimensions ranging from 600x400x400 to 1200x1000x1000 mm.

The purpose of the invention is to reduce the energy capacity.

FIG. 1 shows a heat-shrink oven, a cross-section; in fig. 2 - the same, longitudinal section; in fig. 3 - working area of the heat-shrink oven chamber, top view

The heat-shrinkable furnace contains a heat-insulating chamber 1, in which blocks of heating elements 2, centrifugal fans 3, guide plates 4.5 and housings 6 separating the working space of chamber 1 from centrifugal fans 3 and guide plates are installed at its side walls. 4.5. The covers 6 have openings 7 with nozzles 8 located at the level of the cargo branch of the conveyor 9. The guide plates 4 and 5 are installed in pairs in parallel with the formation of channels 10 and 11 for the passage of air and are arranged perpendicular to the covers 6 and the side walls of the chamber 1 and under angle to one another. The centrifugal fans 3 are located at the junctions of the channels 10, 11 and the nozzles 8 are located at the opposite ends of the latter. The blocks of heating elements 2 in the cross section of their shape are trapezoidal and arranged so that their peripheral sections overlap the cross sections of the channels 10 and 11 directly in front of the nozzles 8, and the middle parts are located between the channels 10,11 and the air is not blown.

The movement of the conveyor 9 for supplying the packages 12 to the furnace and forcing them out of the furnace is associated with the operation of the entrance 13 and exit 14 of the furnace doors.

Shrink lie works as follows.

Before the packaging 12 is fed into the oven, it is preheated for 25-30 minutes to a temperature in the furnace working space of 220-250 ° C. The package 12 in the shrink film is fed into the chamber 1 by the conveyor 9 with the door 13 open and the fans 3 off and stopped in a fixed position After zack

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digging the door 13 turns on centrifugal fans 3, which suck air from the upper part of the working space of chamber 1 and direct it to channels 10 and 11 formed by guide plates 4 and 5. The air passing through the blocks of heating elements 2 is heated and directed on the front and rear faces of the packages 12 due to the location of the nozzles 8 at the level of the cargo branch of the conveyor 9. The location of the nozzles 8 at the level of the cargo branch of the conveyor 9 is necessary to ensure the supply of hot air primarily to the bottom w package part 12 finds schuyus on the cold branch of the loading conveyor 9, and requiring more intensive heating. With this arrangement, the nozzles 8 oncoming air flows out of oppositely located nozzles 8, meeting on the frontal and rear surfaces, uniformly heat the film membrane. At the same time, the film is heated on the side faces of the packaging 12 due to convection of hot air from the covers 6 heating from the middle parts of the blocks of heating elements 2 located between the channels 10 and 11. Thus, the film in which the package is wrapped is heated for 20-30 seconds to the softening temperature of the film, .e. to 200-230 C. After that, the centrifugal fans 3 are turned off, the door 14 is opened and the package 12 on the conveyor 9 leaves the chamber 1. The door 14 is closed. With natural cooling, shrinkage of the film occurs, as a result of which it tightly wraps the packaged load, for example, asbestos briquette. The furnace is ready for a new heating cycle.

The reduction in energy intensity is provided by reducing the power of the heating elements and reducing the power of the drives of the centrifugal fans. This becomes possible due to the proposed change in the shape and location of the described channels 10, 11, along which air moves from the centrifugal fan 3 to the nozzles 8 in the straight line direction, which allows reducing their length, increasing the air flow.

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Claims (2)

1. A heat-shrinkable furnace containing 1 chamber with inlet and outlet doors, blocks of heating elements placed inside the chamber near its side walls, centrifugal fans, guide plates and covers that separate the working space of the chamber from the fans, blocks of heating elements and guides Plates with holes with nozzles located at the level of the cargo branch of the conveyor are distinguished by the fact that, in order to reduce energy consumption, the guide plates are equipped with a 1574508 0 five The pairs are paired in parallel with the formation of channels for air passage, with the guide plates arranged perpendicular to the covers and side walls of the chamber and at an angle to one another, centrifugal fans are placed at the junction of the channels, and the nozzles are located at opposite ends of the latter. 2. The furnace according to claim 1, characterized in that the blocks of the heating elements in the longitudinal section have the shape of a trapezium and are arranged so that their peripheral sections overlap the cross-sections of the channels in front of the nozzle 13 FIG. 2 -V Tool d Fig.Z