SU785615A1 - Method of convection drying - Google Patents

Description

The invention relates to the field of use of solar energy, in particular for drying agricultural products.

A known method of convective drying by circulating air in a closed loop And

When using the known method for drying agricultural products, a lot of time is spent, because, as a rule, in a drying chamber using heat, solar energy, a trolley is located with boxes of dried products placed on it in several rows, i.e. the volume of dried products is quite large. _s

The aim of the invention is to reduce. drying time. ,

This goal is achieved by periodically changing the direction of air movement. ₂

The drawing shows a plant for convective drying of agricultural products using solar energy, which implements this method.

The installation comprises a fan 1 with a discharge duct · 2 having a nozzle 3, an air heater 4 connected to the drying chamber 5 having an exhaust pipe 6 to the lower part of the chamber ⁽ 5 is connected to a recirculated heat-insulated duct 7 to create a closed air circulation circuit. The nozzle 3 and the exhaust pipes 6 have control flaps 8 and 9, and a humidifier 10 is installed in the discharge duct 2. The electric drive of the fan 1 is equipped with a phase switch (not shown).

The upper wall 11 of the heater 4 is made of translucent material, and the heating element 12 is made in the form of a corrugated blackened metal sheet.

Inside the drying chamber 5 is installed with the possibility of moving the trolley 13 with trellis boxes 14 for dried agricultural products. The installation operates as follows.

The sun's rays, passing through the wall 11 of the heater 4, give their thermal energy. Using a fan 1, external air is pumped through the pipe 3 into the air heater 4. Next, the heated air is supplied to the drying chamber 5, where a trolley 13 with drawers 14 is installed. The air in the chamber 5 is passed through the grate boxes 14, while the heated air takes moisture from the dried agricultural products , partially through the exhaust pipe 6, the air goes out, and the main part of the air is passed through a recirculated heat-insulated duct 7, thereby providing a closed loop circulation.

Instead of the air removed through the exhaust pipe 6 from the atmosphere, external air is sucked in the same amount.

To ensure uniform drying of agricultural products and reduce drying time periodically change the direction is important moisture content of heated air. In this regard, during drying, it is necessary to adjust the humidity. To do this, use a humidifier 10, and humidity is regulated depending on the readings of a psychrometer (not shown).

Thus, due to the periodic change in the direction of air movement, time is reduced while maintaining the quality of dried agricultural products.

Claims (1)

The invention relates to the use of solar energy, in particular for the drying of agricultural products. There is a method of convective drying by skipping air around a closed loop fl. When using a known method for drying agricultural products, a lot of time is spent, since, as a rule, a trolley with several products with dried products, i.e., is located in a drying chamber that uses solar heat. the volume of dried products is quite large. The aim of the invention is to reduce the drying time. The goal is achieved by periodically changing the direction of air movement. The drawing shows a plant for convective drying of agricultural products using solar energy, which implements this method. The installation contains a fan 1 with a pressure air duct 2 having a hose 3, an air heater 4 connected to a drying chamber 5 having a chimney 6, a recirculation heat insulated air duct 7 is connected to the lower part of the chamber 5 to create a closed air circulation circuit. . The pipe 3 and the exhaust pipe 6 have control valves 8 and 9, and a humidifier 10 is installed in the discharge duct 2. The electric drive of the fan 1 is equipped with a phase switch (not shown). The upper wall 11 of the air heater 4 is made of translucent material, and the heating element 12 is made in the form of a corrugated blackened metal sheet. Inside the drying chamber 5 is installed with the possibility of moving the trolley 13 with trellised boxes 14 for dried agricultural products. The installation works as follows. 378 The sun's rays, the passage through the wall 11 of the air heater 4, give up their energy. With the help of a fan 1, external air is pumped through pipe 3 into the air gap 4. Next, heat air is fed into the drying chamber 5, where trolley 13 with pins 14 is installed. Air in chamber 5 is passed through grate bins 14, while the heated air draws moisture from dried agricultural products, partly through the exhaust pipe 6, the air comes out, and the main part of the air is passed through the recirculation heat-insulated air duct 7, thereby ensuring circulation in a closed circuit. Instead of the air removed through the exhaust pipe 6 from the atmosphere, outside air is sucked in with the same amount. To ensure uniform drying of agricultural products and reduce the time, cytmcH periodically changes the direction of air movement. It is very important that the moisture content of the heated air {scansify the drying process, for example, silk mulberry cocoons). Therefore, it is necessary to regulate the humidity during drying. For this, a humidifier U is used, and the humidity is regulated depending on the readings of the psychrometer (not shown). Thus, by periodically changing the direction of air movement, time is reduced while preserving the quality of the dried agricultural products. Claims of the method of convective drying, mainly agricultural products using solar energy by circulating air in a closed loop, characterized in that, in order to reduce the drying time, they periodically change the direction of air movement. Sources of information taken into account during the examination 1. USSR author's certificate No. 619295, cl. Р 26 В 3/04, 1977.