RU2642954C1 - Heat exchanger for electric food driers - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to energy saving, namely to devices for heat energy recovery in drying installations, and can be used, mainly, in household electric desiccants for vegetables, berries, fruits and other products with a sharp reduction in electricity consumption. All known household electric food driers during operation are discharged with moist air into the surrounding space and all heat received from the electric heater. Heat exchanger is a nozzle consisting of concentrically arranged shells of different thermal conductivity materials, forming channels for incoming and outgoing air flows with their optimal heat exchange, inner shell is made with a varying height. This design of the claimed heat exchanger makes it easy to install and remove it without any connecting operations and devices for connection to dryers, and the inner shell with a variable height allows it to be used for a different number of sections (pallets) installed in the dryer and even with different models of dryers (with the same diameter). Counter motion along the surfaces of the middle shell of the two streams creates optimal heat exchange regime, providing the necessary maximum possible heat recovery. At the same time, energy costs are reduced several times, that in the general scale of mass use of electric dryers will provide energy saving in the domestic sector in significant amounts.

EFFECT: proposed heat exchanger reduces power consumption several times while maintaining the quality and duration of drying of products; it does not require any assembly with dryers, is compact and convenient to use.

1 cl, 1 dwg

Description

The invention relates to the field of energy conservation, in particular to devices for recovering thermal energy in drying plants, and can be used mainly in household electric dryers for vegetables, berries, fruits and other products, providing a sharp reduction in energy consumption.

All well-known household electric dryers for food, for example, Alvin SU-1, EzidriUltra FD 1000, SUPRA DFS-211, Veterok, Veterok-2, Polaris PFD 0205AD, Sukhovey-3, Sukhovey MP-5, Smile FD 993, Saturn ST-FP0111 and other models, in the operating mode of operation, discharge with moist air into the surrounding space and the heat received from the electric heater. At the same time, the use of recirculation in a closed loop even of a part of the air flow prolongs the drying time and adversely affects the quality of the products, while the energy saving is negligible.

Known designs of heat exchangers with their complexity and cumbersomeness in everyday conditions are practically not applicable for these purposes. Simple and convenient analogues were not found.

The aim of the invention is the acquisition of commercially available and newly developed models of household electric dryers with compact, simple and easy to use heat exchangers that reduce several times the energy consumption while maintaining the quality and duration of drying of products.

This problem is solved in that the dryers manufactured by the plants are equipped with heat exchangers that do not require assembly - nozzles, consisting of concentrically arranged shells of different shapes from materials of different thermal conductivity, forming channels for intake and discharge of the air flow with optimal heat transfer, while the inner shell is made with a changing tall.

This design of the inventive heat exchanger makes it easy to install and remove it without any connecting operations and devices for connecting to dryers, and the inner shell with a variable height allows you to use it with different dryers with a different number of sections (pallets) installed in them.

The description of the device of such a heat exchanger is illustrated by the attached figure with its axial section.

The inventive heat exchanger is a nozzle consisting of several concentrically located shells, between which there are channels (slots) for the passage of air. The inner shell 1 with a movable base 2 (for example, a light cylinder) is made, like the outer (3), from a heat-insulating material or from metal with a heat-insulating coating. The middle shell 4, on the contrary, has good thermal conductivity. The surface of this shell can be developed by longitudinal ribbing or corrugation. All shells are fastened by pins 5, providing a uniform gap between them for the passage of air flow.

In working condition, the dryer 6 with pallets 7 is located inside the heat exchanger, which rests on its cover 8 with its toroidal bell 9.

For visual control of the temperature in the dryer, it is advisable to provide the possibility of installing a thermometer 10, for example, an axial bimetal, at the end of the outer shell 3.

The inventive heat exchanger is used as follows. Loaded by the products to be dried, the section-pallets 7 are installed on the electric dryer 6, closed with a lid 8, after which the dryer is turned on and the desired temperature or the program of the thermal regime of drying are set. Then, the heat exchanger is put on it coaxially, which is provided by the protruding ends of its pins 5. In this case, the heat exchanger, resting on the cover 8 with its socket 9, covers its outlet hole with it and fits snugly to its surface, and the movable base 2 of the inner shell 1 with its end face so it fits snugly on a flat table surface.

Heated air is supplied through the loaded pallets 7, moistened with evaporated liquid and removed through the opening of the lid 8 (here its temperature can be controlled by the readings of the thermometer 10). Further, along the slit-like channel between the middle (4) and outer (3) shells, the moist air stream descends, giving off its heat to the middle shell 4, after which, already cooled, it is directed by flanging upwards into the surrounding space.

Since the free access of ambient air to the intake openings of the dryer 6 is blocked by the base 2 of the inner shell 1, fresh air flow is drawn by the fan through the slit-like channel between this shell and the heated middle shell 4. The oncoming movement of the flows along its two surfaces creates the optimal heat transfer regime, providing the necessary maximum possible heat recovery, as a result of which a fresh air stream enters the dryer already in a heated state.

At the same time, energy costs are reduced several times, and this, with the systematic drying of berries, fruits, vegetables, mushrooms, medicinal herbs using only one unit, gives a monthly savings of more than 100 kWh, so that in the general scale of mass use of electric dryers with such heat exchangers energy savings in the domestic sector can be significant.

Claims (1)

A heat exchanger for electric food dryers having channels for oncoming air flows over the surfaces of the heat transfer wall, characterized in that it is made in the form of a nozzle from concentrically located shells, the middle of which is made of a material with high thermal conductivity, and the others are insulated, and the inner shell equipped with a movable base with the possibility of using a heat exchanger with dryers of different heights and with a different number of pallets.

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