Method of packing products with increased temperature

Description of the invention

The subject of the invention is a method of packaging products with elevated temperature, in particular metallurgical powder, including powder for zipper closures, packed in paper bags with a foil insert.

In the case of packaging products with elevated temperatures, we are dealing with the accumulation of water vapor after packing within the collective packaging, i.e. the so-called. hood on the pallet.

To prevent the adverse effects of the accumulation of unfavorable gases, in the case of food or pharmaceuticals, blowing with gases is used to ensure the sterility of the atmosphere in the package. In the production of oxygen for industrial purposes, significant amounts of liquefied nitrogen are produced, which is an inert gas, cheap to obtain, easy to transport, non-explosive.

From the Polish patent description 177976 there is known a device which has a compartment for aseptic filling of the package with the product, a compartment for sealing said package with two sealing elements and a transport device for transferring the packages to two compartments, the second compartment containing a fixed nozzle for nitrogen injection and the nozzle is placed between two movable sealing elements.

From the Japanese patent application JPH09295677 we learn about the use of a small amount of gas, creating a gas filling tray from the part of the tray on which the matter to be packed is to be placed, and the lid to cover the tray, setting the gas blower - in the inlet on the upper surface of the lid and placing gas outlet around the lid. An auxiliary rib for reinforcement is present on the slanted portion around the lid. The air outlet is formed by drilling into the trap-like horizontal surface of the secondary rib. Thus, the gas outlet is located on the secondary rib. The gas injection inlet is also located on the top surface of the lid. Thus, in gas filling, the material to be packaged is first placed on a tray, and a lid having a gas inlet and a gas outlet is placed on the tray to cover. Then the edge of the tray and the rim of the lid are matched to each other. The filling gas is then blown from a gas injection inlet located on the top surface of the lid.

From the American patent application US2010055275 we learn about methods of packaging meat, fish, poultry, vegetables or other food products. The package of the present invention is a vacuum skin package comprising a multi-layer film comprising at least one layer of an organic acid-modified ionomer blend and at least one layer of an ethylene-containing polymer such as ethylene vinyl acetate, the film having specific gas permeability requirements.

The technical problem in the invention is the removal of the accumulating water - water vapor under the hood foil when collectively packed on pallets during the hooding process of metallurgical mixtures packed in paper bags with a foil insert. This accumulation of water vapor is due to the packaging of the product at a temperature of approx. 40°C in bags. Moisture of the product resulting from the accumulation of water vapor adversely affects the parameters of the product. In the previously used solutions, in order to avoid the accumulation of steam under the hood, the packaging of the product on pallets was divided into stages including cooling in dry bags with backfill. Such a process, however, requires the provision of an appropriate room with conditions for cooling and storing the finished product.

The essence of the invention is the elimination of water vapor and its condensation during the hooding of the material at elevated temperature, accumulating under the hood of collective packaging on a pallet, which will make it possible to speed up the packaging process and guarantee the appropriate quality of the product.

Unexpectedly, it turned out that the application of injection of inert gas in a dry and cool form, i.e. nitrogen, caused the removal of the adverse effects of water vapor condensation under the hood of the sorted material by removing moist air and cooling it.

The method of packaging products with elevated temperature according to the invention in the range from 20°C to 50°C, which are packaged in paper bags with a foil insert, and then placed on a pallet and covered with a plastic hood, is characterized by the fact that after stacking the bags on pallet after they are covered from the top and sides with a hood, nitrogen is fed under the hood with an efficiency of 0.5 to

nm³ onto the pallet, after which the plastic hood closes the pallet from the bottom, preferably gluing the foil of the hood. Preferably, a stack of bags containing powder for zipper closures is blown through.

The advantage of using the invention is simplicity, the use of a material available at a favorable price, which is a by-product of the industrial production of other gases such as helium, oxygen, etc.

An additional advantage resulting from the very properties of the gas is its ease of collection, storage and adjustment of its parameters.

Nitrogen is commonly used in industrial plants for packaging, e.g. during the bagging process, food products requiring packaging in an inert atmosphere and ensuring the sterility of the packaging process.

Example

The material, i.e. powder for zipper closures used in metallurgy, is packaged in paper bags with a foil insert.

The material is then dumped from the packaging machine onto a set of conveyors. During transport, bags are formed and then placed on a pallet.

When the material is bagged, it is around 40°C.

Then, the material in the form of bags is hooded with a Stretch Hood machine. The pallet protection film has shrinking properties. In order to eliminate moisture between the bags, a nitrogen purge is used during the hood application process, under the hood, where gas exchange is naturally limited, and the hood itself is tight, so there is no risk of additional moisture getting under the hood. Immediately after blowing, the hood is compressed. Nitrogen is stored in liquid form, and the use of an evaporator allows you to adjust the nitrogen parameters to the set operating conditions.

Approximately 1.5 Nm is consumed during the hooding process³ on the pallet. The demand for nitrogen at the stage of packing into bags is about 30-60 m3³/h at a pressure of 0.03-0.05 MPa.

Then, after applying nitrogen, the hood is sealed or welded from the bottom of the pallet, thus maintaining a favorable atmosphere within the hood.

The invention is applicable not only in the process of packing metallurgical powders, but also other materials with elevated temperatures that require maintaining a sufficiently low level of product moisture.

The given embodiments do not exhaust the possibilities of using the invention.