JPH0536711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a drying device for foods, wood, clothes, etc.

Prior Art Figure 3 shows a conventionally used heating type drying device. In the figure, 01 is a drying chamber, 02
is the item to be dried, 03 is the fan, 04 is the heater, 05
is a heat exchanger, 06 is an intake port, and 07 is an exhaust port.

This will be explained as a drying device that removes moisture. A material to be dried 02 is placed in a drying chamber 01, and air inside the chamber is circulated by a fan 03. Intake of outside air 06
The heat exchanger 05 exchanges heat with the exhaust gas, and the temperature rises. The air is further heated by a heater 04 to become dry air and introduced into the refrigerator. On the other hand, the air containing moisture coming out of the material to be dried 02 is heated in the heat exchanger 05 and then released from the exhaust port 07.

Problems to be solved by the invention A: Heating requires a large amount of energy and running costs are high.

(b) It is necessary to keep the inside of the refrigerator in a high temperature state, and it cannot be used for objects that will deteriorate in quality.

C. As the moisture content of the material to be dried decreases, the drying speed slows down.

Means for solving the problem Heat exchange is performed between the discharge gas of the vacuum pump (compressor) and the suction gas, and the drying gas is supplied to the drying device.

Function: Supplies room temperature drying gas into the drying chamber to dry the items to be dried.

Embodiment In the first embodiment shown in FIG. 1, 1 is a drying chamber, 2 is an object to be dried, 3 is a fan, 11 is a vacuum pump or compressor, 12 is a heat exchanger, 13 is a separator, 14 is a demister, 15 ,16,
17 is a valve, 18 is an expansion valve (pressure reducing valve), and 19 is an auxiliary heater.

Although the diagram shows a mesh demister as a separator for separating gas and liquid, it is also a common method to use a cyclone. Although the valves 15 and 16 are two two-way valves that switch the flow paths, they can also be configured with one three-way valve. Although an expansion valve is used to reduce pressure, a capillary tube, orifice, etc. can also have the same function.

Although this will be described as a drying device for removing moisture, the same applies to drying devices for removing substances that evaporate and condense, such as solvents. The material to be dried 2 is placed in the drying chamber 1, and the vacuum pump or compressor 11 is first
The air inside the refrigerator is sucked in and discharged to the outside through the heat exchanger 12, demister 14, and valve 15 (valve 16 is closed). This step is omitted when drying the interior of the refrigerator at normal pressure. When a predetermined pressure is reached at which a large amount of water evaporates from the material to be dried 2, the valve 15 is closed and the valve 16 is opened to form a closed cycle, and the air containing moisture in the refrigerator is sucked into the vacuum pump or compressor 11. The high-pressure and high-temperature air that is pressurized is cooled by the heat exchanger 12, and moisture is condensed. Further, the liquid and gas are separated by a separator 13, and condensed water is collected in the separator 13 and discharged through a valve 17. On the other hand, the air, which is a non-condensable gas, and the uncondensed gaseous moisture are separated into mist by a demister 14, go through a valve 16 to an expansion valve 18, are depressurized, become a low-pressure gas, and are heated by a heat exchanger 12. The air is then returned to the refrigerator as dry air with high temperature and low moisture content. There is a fan 3 inside the refrigerator, which circulates the air inside the refrigerator. Auxiliary heater 1
9 is provided to keep the temperature inside the refrigerator constant, but may be omitted if there is little heat radiation. There are various factors that determine whether or not to create a vacuum inside the refrigerator, and the amount of water evaporated from the material to be dried.
Qualitatively, if the degree of vacuum is increased, the rate of evaporation of the material to be dried increases and the amount of non-condensable gas decreases, improving efficiency, but heat transfer becomes worse and it becomes difficult to impart the heat of evaporation to the material to be dried. If the pressure inside the refrigerator or the pressure inside the separator rises too much during operation, stable operation can be achieved by releasing it from the valve 15.

Next, the second embodiment shown in FIG. 2 is the one in which a heat exchanger 20 is added to the first embodiment described above, and the evaporation pressure of condensed gas such as moisture in the refrigerator is high.
This is a good system when the steam pressure is close to saturated steam pressure.

Only the differences from the first embodiment will be explained as follows. The high-pressure, high-temperature air leaving the vacuum pump or compressor 11 is cooled by a heat exchanger 20, and moisture is condensed. Furthermore, the moisture and gas are cooled in the heat exchanger 12, and the separator 1
Send to 3. Air inside the refrigerator is circulated through one side of the heat exchanger 20, and is heated here to become dry air.

Effects of the invention A: By pressurizing with a vacuum pump or compressor, the latent heat of condensation can be recovered in a heat exchanger, resulting in high efficiency and low running costs.

(b) Since the inside of the refrigerator is vacuumed, the inside of the refrigerator can be dried at low temperatures.

In addition, the system can be established even if the inside of the drying chamber is kept at normal pressure and the vacuum pump is used as a compressor, which is efficient and eliminates the need for the drying chamber to be a vacuum container.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a first embodiment of the drying apparatus of the present invention, FIG. 2 is a schematic diagram of a second embodiment of the present invention, and FIG.
The figure is a schematic diagram of a conventional device. 1... Drying warehouse, 2... Material to be dried, 3... Fan, 11... Vacuum pump or compressor, 12
...Heat exchanger, 13...Demister, 18...Expansion valve (pressure reducing valve).

Claims (1)

[Claims] A vacuum pump or compressor that sucks the gas in the drying chamber, a heat exchanger that cools the gas discharged from the vacuum pump or compressor and condenses the moisture in the gas, and a heat exchanger that separates the moisture in the condensed gas. It has a separator and a pressure reduction mechanism that reduces the pressure of the gas from which moisture has been separated by the separator, and the gas reduced in pressure by the pressure reduction mechanism is introduced into the heat exchanger, and after exchanging heat with the discharged gas, the drying chamber A drying device characterized by forming a closed circuit for internal circulation.