RU2198358C2 - Quick freezer for fruit, berries and vegetables - Google Patents

Abstract

FIELD: agriculture. SUBSTANCE: quick freezer has screen trays moved into chamber over guides. Fruit and vegetables are frozen by flow of air fed over closed ring through one fan, distributing cells, tray for freezing products in fluidized layer, air coolers and trays for freezing products in dense layer. EFFECT: low cost of manufacture; reduced power requirements. 2 cl, 4 dwg

Description

 The invention relates to refrigeration and can be used in refrigerators, food enterprises that produce frozen fruits and vegetables. Known freezers used in industry for freezing food products (see Refrigeration. Handbook. The use of cold in the food industry. // M: Food industry, 1979).

 The indicated freezers are rather cumbersome and metal-intensive and are mainly designed for relatively large capacities, which is not always acceptable for the production of frozen fruits, berries and vegetables in small enterprises and farms.

 The closest analogue is the freezing apparatus (see the patent of the Russian Federation 2036396) "Method for freezing fruits and vegetables and a device for its implementation", the essence of which is that the products are moved on a conveyor and frozen in a fluidized bed during alternation along the length of the conveyor zones with jets of increased air pressure with zones without such jets, and freezing is carried out when the product is located on the conveyor belt in a dense layer and air is supplied to it in a downward flow. The device contains a heat-insulated chamber, divided by partitions into freezing and freezing sections, a food conveyor, air coolers located under it, an air distribution system located under the conveyor in the freezing section and containing rows of cells and rotary blades installed under the cells with the possibility of their alternating overlapping. Air cooler fans are installed with the possibility of air supply in the first section under the conveyor, and in the second section - on the conveyor from above.

 The specified method and device have quite complex and relatively metal-intensive and expensive conveyors and a drive to them, several fans for supplying air under the product and on top of it. All these transporting mechanisms have a rather high share of the cost in freezers with low required capacity (50-250 kg / h) and their use in such devices is irrational. In addition, conveyors occupy a rather large volume of a thermally insulated chamber. In such devices, it is impossible to freeze fruits, berries or vegetables in fluidized and dense layers with the help of a single fan.

 The basis of the invention is the task of improving the “Freezing apparatus for fruits, berries and vegetables”. The technical result is to reduce material costs in the manufacture of the apparatus and energy costs during its operation, which is especially important for devices of low productivity (50-250 kg / h). The specified technical result is achieved due to the fact that in the "Freezing apparatus for fruits, berries and vegetables" containing a heat-insulated chamber, air coolers, fan, air ducts, mesh trays, control blades with distribution cells, air coolers are installed between the mesh tray with a fluidized bed of the product and mesh pallets with a dense layer of product for air circulation in a closed ring including a fan, distribution cells, a pallet with freezing of the product in ps fluidized bed, air coolers, trays with freezing the product in a dense layer.

 In addition, to reduce energy costs, by significantly reducing the air velocity when passing through a dense layer, depending on the geometric dimensions of the fruit or vegetables, the ratio of the cross-sectional area of the supporting mesh for the fluidized bed of the product to the cross-sectional area of the supporting mesh of the dense product layer can be 0, 25; 0.33; 0.50. The ratio of the areas is selected by placing one mesh pan in the freezing section of the product in the fluidized bed and two, three or four mesh pallets in the section of freezing the product in a dense layer.

 The invention is illustrated by drawings, where in FIG. 1 shows a freezing apparatus for freezing fruits, berries and vegetables.

 In FIG. 2 shows a plan view of distribution cells for air flow.

 In FIG. 3 shows the position of the blades for directing air into odd cells, and FIG. 4 - into even cells.

 The freezing apparatus for fruits, berries and vegetables includes a fan 1, rotary blades 2, distribution cells 3, a mesh tray 4 for freezing in a fluidized bed, a mesh 5 preventing the product from being carried away by the air flow, an air cooler 6 with an increased fin spacing, an air cooler 7 with a reduced fin spacing , mesh pan 8 for freezing in a dense layer, a thermally insulated chamber 9 and guide vanes 10.

 The freezing apparatus for fruits, berries and vegetables works as follows. Outside the apparatus, the product to be frozen is loaded into the mesh tray 4. Then, through special guides (not shown), the product tray is fed through the wall opening into the heat-insulated chamber 9 and installed above the distribution cells 3. Turning the blades 2 by a special mechanism (not shown) and blocking even cells, in odd cells, the air velocity is approximately doubled, which contributes to the erosion of the product and its fluidization in areas above the cells (Fig. 3). Then, by turning the vanes 2, the odd cells overlap and the product is brought into a fluidized state over the even cells with a high-speed flow (Fig. 4). This operation provides fluidization on the grid 4 and freezing of the product, which, with further freezing, prevents freezing of the product particles. To prevent product entrainment by an air flow above the mesh pan 4, a mesh 5 is installed in the duct. The heated and moist air after the fluidized bed enters the fin-tube air cooler 6 with an increased pitch between the ribs, where a significant amount of moisture settles mainly in the form of frost and partial cooling of the air occurs. In the air cooler 7, with a reduced pitch of the ribs, the final cooling of the air and frost formation occurs.

 Cooled air from the air cooler 7 passes through a dense layer of product in pallets 8 and finally freezes it. Having passed through the product, still cold air is taken in by the fan 1 and is fed to freeze the newly fed product in the fluidized bed. At the entrance of the pallet 4 with the warm product, the previously loaded pallets move through the chamber and one pallet 8 with the frozen product passes through the opening in the wall of the insulated chamber 9, where it is unloaded and again fed to the loading of the warm product. To reduce the aerodynamic resistance to air flow in the duct, guide vanes are installed 10. The air flow circulates in a closed ring: fan, rotary blades with cells, a tray with freezing the product in a fluidized bed, air coolers, pallets with freezing the product in a dense layer.

 To reduce energy costs, it is most advisable to place one mesh pan in the freezing section of the product in the fluidized bed, and two, three or four pallets in the dense section of the dense bed, depending on the type of frozen product. Since the air flow rate at any point of the freezing apparatus is the same, the highest air flow rate and the greatest aerodynamic losses will occur when air (filtering) passes through a dense layer of the product. When two, three or four pallets are installed in a dense layer of a product in a dense layer, the sectional area of this section proportionally increases and the air filtration rate decreases through a dense product layer, which makes it possible to equalize the air flow through the product layer in the freezing section and in the freezing section.

 The freezing apparatus for fruits, berries and vegetables is universal and can be used to freeze small batches of various fruit and vegetable raw materials in relatively small farms and other small enterprises that produce frozen products.

Claims (2)

 1. A freezing apparatus for fruits, berries and vegetables, comprising a thermally insulated chamber, a fan, air separators, mesh trays, rows of distribution cells with rotary blades, guide vanes for air flow, characterized in that the air coolers are installed between the mesh tray with a fluidized bed of the product and the mesh pallets with a dense layer of the product for circulating the air flow in a closed ring including a fan, distribution cells, a pallet with freezing of the product in pseudo izhennom layer coolers, trays with freezing product in the dense layer.  2. The freezing apparatus for fruits, berries and vegetables according to claim 1, characterized in that 0.25; 0.33; 0.50.

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