RU2514275C2 - Method for food products drying and device for method implementation - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention relates to food industry. The method envisages the product placement into a drying chamber and continuous supply of a heated drying agent into the chamber. The drying agent temperature in the drying chamber is maintained at a level no higher than 60°C. The drying chamber inner volume is continuously vacuumised by way of the drying agent suction into the drying chamber through small perforation holes of the drying agent inlet wall of the drying chamber with a blower the suction device whereof is placed outside the drying chamber directly near the opposite drying agent outlet wall of the drying chamber that is perforated with large holes. The drying agent is returned for repeated recirculation. The method implementation device includes a thermally insulating sealed body attached to the base and enclosing (with space gaps) the drying chamber and a technical section conjugated with the drying chamber wall. The technical section has a window for the drying agent outlet into the space gaps ensuring the drying agent return into the drying chamber. A blower, an evaporator and a condenser of the heat pump and a heater are sequentially placed inside the technical section along the drying agent path. The drying chamber wall, wherewith the technical section is conjugated, is perforated with holes having a major diameter while the opposite drying chamber wall at the drying agent inlet into the chamber is perforated with holes having a smaller diameter.

EFFECT: invention ensures minimisation of heat losses and electric energy expenditures.

2 cl, 2 dwg

Description

The invention relates to the food industry, and in particular to means for drying products, mainly vegetable, and can be used in other industries for drying other materials.

A known method of drying, including drying the product at room temperature for one hour, placing it in a drying chamber, provided with the ability to evacuate, and drying at a temperature of 60-70 ° C with a cyclic pressure reduction from 0 to 0.04 MPa (RF patent No. 2133094 , (22) 01/04/1996, (45) 07/20/1999). The implementation of this method certainly requires a means of heating the drying agent (air), a means of introducing the drying agent into the chamber, means of evacuation (i.e. pumping the drying agent out of the chamber). All of these funds are energy-consuming, and the evacuating pumping of the drying agent is an irrevocable loss of heat and condensate.

A known method of drying a food product according to the patent of the Russian Federation No. 2195824, (22) 23.06.2000, (45) 10.01.2003, according to which the product is blanched in a dryer with a microwave energy of 0.5-3.0 W / g and evacuation in 200- 400 mmHg while centrifuging the product, and the removal of free water is carried out by microwave energy of 1.0-0.25 W / g and a vacuum pressure of 30-100 mm RT. Art. The disadvantages of this method: complex, expensive, energy-consuming equipment, the presence of heat losses of the drying agent and useful product vapors, the vacuum cycle, which drains the drying time.

The known drying method according to the patent of the Russian Federation No. 2410882, (22) 02.25.2009, (45) 02.10.2011, (prototype), characterized in that the heated drying agent is fed into the vacuum chamber to the product to be dried there placed on the sieve, a vacuum is created in the chamber and at the same time, the product sieve is centrifuged at a speed of 500-1000 rpm.

The disadvantages of this method are the same as that of the analogue of patent No. 2195824.

The technical result achieved by the claimed drying method, the intensification of the drying of the product due to the continuous vacuuming of the drying chamber, cheaper method. This technical result is ensured by the fact that in the method of drying a food product placed in a drying chamber, including heating the drying agent, feeding it into the drying chamber and evacuating, the drying agent is continuously supplied to the drying chamber, the internal volume of the drying chamber is continuously evacuated by suction of the drying agent into the drying chamber through small holes in the perforation of the inlet wall of the drying chamber by a fan, the suction of which is located outside the drying chamber immediately near opposite outlet wall of the drying chamber, perforated by large holes, and returning the drying agent to multiple recycling without emissions to the outside.

The claimed drying method is implemented using the device for drying food products described below.

A device for drying food products according to the patent No. 2045187, (22) 05/05/1993, containing a drying chamber with a thermally insulating body, with a packet of screens located inside the chamber with the formation of a channel for passage and heating of the drying agent drawn by a fan, the suction of which is located in the lower parts of the housing of the drying chamber directly below the sieve package, and a heat exchanger with condensate collection means.

The disadvantages of this device, taken as the closest analogue, are the low cost-effectiveness of drying due to the emission of a third of the spent drying agent (air) outside, which takes away heat and useful product fumes, and a long drying time.

The technical result achieved by the claimed device is the intensification of the drying of the product with a constant initial volume of the drying agent, reduction of energy consumption and drying time.

This technical result is ensured by the fact that in the device for drying food products containing a drying chamber, a fan, a condenser and a heater installed on the base, an external heat-insulating sealed housing is additionally strengthened on the base, covering the drying chamber and the section connected to the wall of the drying chamber with spatial gaps, inside of which the fan, the evaporator and the condenser of the heat pump and the heater are placed sequentially in the direction of the drying agent, NCA drying chamber, which entails a section perforated with holes of large diameter and the opposed wall of the drying chamber it (inlet therein a drying agent) is perforated with holes of smaller diameter, the section has a window for the exit of the drying agent in the space gap to return to the drying chamber.

The drawing shows the inventive device (two projections). The device comprises a heat-insulating casing 2 mounted on the base 1 with a hermetically closing door 3, a drying chamber 4 and a technical section 6 adjacent to the wall 5 of the drying chamber, in which the heat pump elements (evaporator, condenser) 7 with a retractor fan 8 and electric heaters 9 are mounted. The heat pump consists of an evaporator 10, a condenser 11 and a compressor 12. A moisture collector 13 is installed under the heat pump evaporators 10 with a means of removing moisture from the device. The technical section has a window 14. The drying chamber 4 and the technical section 6 are enclosed by a housing 2 with spatial gaps 15 between the inner surfaces of the housing 2 and the side walls and the ceiling (roof) of the drying chamber. The wall 5 of the drying chamber 4 is perforated with large holes, and the opposite wall 16 of the drying chamber is perforated with holes of a smaller diameter. The compressor 12 of the heat pump is located outside the heat insulating casing.

Inside the drying chamber, the product to be dried is placed on roll-out trolleys in mesh baking sheets. On the bogies, the baking sheets are arranged with the highest possible density evenly throughout the chamber. The filling height of the baking sheets is no more than 5-6 cm.

The device operates as follows: after loading the drying chamber with the dried material, the START button on the control panel turns on the fan 8 and electric heaters 9 to bring the unit into operation. The fan draws in the drying agent from the drying chamber through the openings in the wall 5. A vacuum is created in the drying chamber, and under the action of the vacuum from the opposite side of the drying chamber, the drying agent begins to flow through the perforated openings of the wall 16. The drying agent, penetrating the chamber with the dried product and taking moisture evenly throughout the volume, begins to move to the opposite wall 5 and through its openings to the suction fan. The temperature in the chamber is maintained no more than 60 degrees Celsius. When the device enters the operating mode, the heat pump turns on: moisture evaporated from the drying chamber by the drying agent begins to condense on its evaporator 10. When passing through the evaporator 10, the drying agent loses the temperature of about 3-4 degrees, then it moves through the condenser 11, where it is heated by 3-4 degrees, passes through the electric heaters 9 and enters the drying chamber through the cavities 15. The recycling process continues until the product has completely dried without significant loss of heat of the drying agent, which leads to significant energy savings. During the operation of the device, a vacuum is created inside the drying chamber, which increases the drying speed.

The drying process is automated, the parameters of the device are monitored and regulated by a microprocessor system. Controlled and adjustable parameters: temperature, humidity, pressure in the drying chamber and the amount of liquid discharged. Using this method and a drying device, in contrast to traditional methods and dryers, the drying speed is increased by 2 times, energy savings are 2.5-3 times (depending on the time of year).

The condensation product during the drying of the dried material is a valuable product.

Claims (2)

1. The method of drying a food product placed in a drying chamber, comprising heating the drying agent, feeding it into the drying chamber and evacuating, characterized in that the drying agent is continuously fed into the drying chamber continuously, continuously vacuuming the internal volume of the drying chamber by drawing in and out the drying agent into the drying chamber through small holes in the perforation of the wall of the drying chamber inlet for the drying agent by a fan, the suction device of which is located outside the drying chamber directly near the opposite outlet for the drying agent, the wall of the drying chamber, perforated with large holes, and the drying agent is returned for repeated recirculation without emissions to the outside, while the temperature of the drying agent in the drying chamber is not higher than 60ºC. 2. A device for drying food products comprising a drying chamber mounted on the base, a fan, a condenser and a heater, characterized in that it further comprises an external thermally insulating sealed enclosure fixed on the base, covering the drying chamber with spatial gaps and the technical section connected to the wall of the drying chamber, inside of which the fan, the evaporator and the condenser of the heat pump and the heater are placed sequentially in the direction of the drying agent, the wall dried hydrochloric chamber, which entails a section perforated with holes of large diameter and the opposed wall of the drying chamber it at the inlet of the drying agent it is perforated smaller diameter holes, technical section has a window for the exit of the drying agent in the space gaps, ensuring its return into the drying chamber.