JP2019027726A - Dehumidifying dryer - Google Patents

Abstract

To provide an energy-saving dehumidifying dryer of a simple structure for drying an object to be dried by dehumidifying air in a dry warehouse, capable of drying an object to be dried reducing its moisture content of not higher than 10%, suppressing the power consumption of a heater even upon carrying out the drying at a relatively high temperature, and of easily controlling the indoor temperature.SOLUTION: Air in a drying warehouse is circulated to reduce its relative humidity while keeping the warehouse shielded from the outdoor air. The circulation route 2 of the indoor air is provided with bypass routes 3 (3a, 3c) so that a coolant flowing through a condenser 6 of an air cooler C is cooled by the indoor air a flowing in the bypass routes 3 and by the outdoor air B, and the indoor temperature is controlled by a heater 7 provided in the circulation route of the indoor air, according to the type of an object to be dried .SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dehumidifying and drying apparatus that dehumidifies the air in a drying cabinet that contains a material to be dried, and in particular, dries vegetables and fruits to a moisture content of approximately 10% or less. The present invention relates to the above-mentioned apparatus suitable for the above.

  The dehumidifying and drying device promotes the evaporation of moisture in the object to be dried by reducing the relative humidity of the air in the drying chamber (air in the container) containing the object to be dried using a heat pump type air cooler. Drying is performed. In the dehumidifying and drying apparatus for food, it is necessary to avoid the outside air from being mixed into the air in the cabinet for hygienic reasons.

  As a dehumidifying and drying apparatus for food, there are widely used air coolers (generally referred to as dehumidifiers, hereinafter referred to as “dehumidifiers”) having an evaporation temperature (dew point) of refrigerant of −5 to −15 ° C. It's being used. As shown in FIG. 5, when the internal air A is passed through only the evaporator 25 of the dehumidifier and circulated, the humidity decreases and the internal temperature also decreases. Therefore, a heater 27 is provided in the circulation path of the internal air A in order to maintain the internal temperature at a desired temperature. The dehumidifying and drying apparatus having this structure is simple in structure, low in apparatus cost, and easy to control the internal temperature.

  On the other hand, a dehumidifier having a structure in which indoor air is sucked into a dehumidifier, passes through an evaporator and a condenser of the dehumidifier in series, and blows back the entire amount into the room has been proposed. In this structure, the room temperature rises due to the operation of the dehumidifier. Patent Document 1 discloses a dehumidifier in which a water-cooled precooling cooler that prevents this temperature rise is provided in an air flow path.

  The dehumidifying / drying device of the single dehumidifier can dry the object to be dried by limiting the relative humidity of the internal air to about 20%. When the relative humidity of the internal air is to be lower than this, for example, 10% or less, an air cooler (hereinafter referred to as “refrigerator”) whose evaporating temperature is lower than that of the dehumidifier, for example, −25 ° C. Say). In a dehumidifying and drying device equipped with a refrigerator, the internal air passes only through the evaporator of the refrigerator, and the condenser of the refrigerator is cooled by outside air, thereby suppressing the temperature rise of the internal air due to the operation of the dehumidifier However, since two air coolers must be provided, there is a problem that the apparatus cost increases.

  The inventor of the present application adjusts the temperature in the refrigerator by switching the air passing through the condenser of the refrigerator to the indoor air and the outside air with a damper in the dehumidifying and drying apparatus for food provided with the dehumidifier and the refrigerator. A technique is proposed in Patent Document 2. However, the structure proposed in Patent Document 2 has a problem that outside air is mixed in the internal air when the damper is switched in addition to the problem of the apparatus cost.

  Further, in Patent Document 3, as a structure of a dehumidifier installed in a room such as a factory, as shown in FIG. 6, a condenser that cooperates with one evaporator 25 is divided into three 26a, 26b, and 26c. Thus, a dehumidifier has been proposed in which two condensers 26a and 26b are used as in-system condensers that allow room air to pass through, and the other one 26c is installed outside the system. Or it is shown that it cools with outside air. The indoor temperature is controlled by controlling the ratio of the refrigerant sent to the condensers 26a and 26b in the system and the condenser 26c outside the system.

JP 2002-228188 A JP 2011-202914 A Japanese Utility Model Publication No. 62-3633

  When making foods such as fruits into powder, it cannot be made into powder unless the water content is 10% or less. Moreover, it is desirable to dry foods with high sugar content or foods with strong acidity at a relatively high temperature of 30 to 50 ° C. A dehumidifier having an evaporation temperature of −5 ° C. to −15 ° C. is used, and only the evaporator 25 is arranged in the circulation path of the internal air, and a decrease in the internal temperature due to dehumidification is suppressed by the heater 27 to obtain a desired internal The dehumidifying and drying apparatus having the structure shown in FIG. 5 that maintains the temperature can only dry the moisture content of vegetables and fruits to about 20%. As a dehumidifying and drying apparatus capable of reducing the moisture content of the object to be dried to 10% or less, a structure using two air coolers, a dehumidifier and a refrigerator, is generally used. However, this structure has a problem that the apparatus cost becomes high. The dehumidifier described in Patent Document 3 is said to be able to reduce the relative humidity of the circulating air to 20% or less. However, even if the relative humidity of the circulating air is set to 20% or less, the moisture content of the material to be dried is 10% or less. It is difficult to make. Moreover, in the dehumidifier of patent document 3, since a several condenser is provided and the quantity of the refrigerant | coolant which flows into each condenser is adjusted, apparatus structure and temperature control become complicated, and apparatus cost becomes high.

  As a dehumidifying and drying apparatus capable of reducing the moisture content of an object to be dried to 10% or less while suppressing an increase in apparatus cost, the conventional dehumidifying and drying apparatus shown in FIG. 5 is a freezer having a low dew point temperature. It is possible to change to a machine. However, this structure can provide the device at a relatively low cost. However, when drying is performed at a high temperature, the power consumption of the heater increases to maintain the internal temperature at a high temperature, and the running cost increases. Happens.

  This invention can dry the moisture content of the material to be dried to 10% or less, and can suppress the power consumption of the heater even when drying at a relatively high temperature. An object of the present invention is to obtain an energy-saving dehumidifying and drying apparatus that can easily control the temperature.

  The dehumidifying and drying apparatus according to the present invention is a dehumidifying and drying apparatus that dries an object to be dried in a drying cabinet by circulating the air in the drying cabinet with the outside air blocked to reduce the relative humidity of the air in the cabinet. is there.

  In the dehumidifying and drying apparatus of the present invention, the bypass path 3 (3a, 3b, 3c) is provided in the circulation path 2 (2a, 2b, 2c) of the internal air that is blocked from outside air, and the condenser 6 ( 6, 6 a, 6 b) is a heater in which the refrigerant flowing through the bypass passage 3 is cooled by the internal air a and the external air B, and the internal temperature is adjusted in the internal air circulation path according to the type of the object to be dried. 7 to adjust.

  About 70% of the air necessary for cooling the refrigerant passing through the condenser 6 is returned to the circulation path through the internal air a branched from the internal air circulation path 2, and 30% is cooled by the outside air B. Energy saving of the heater 7 is achieved. The ratio between the bypass air and the outside air can be adjusted by controlling the rotational speeds of the cooling fans 9a and 9b disposed in the internal air region 3b and the outside air region 8, respectively. Further, the adjustment of the drying temperature according to the type of the object to be dried is performed by the energization amount of the heater 7.

  By using a refrigerator having a dew point temperature of about −25 ° C. as the air cooler, the moisture content of the object to be dried when drying fruits and vegetables can be dried to 10%. Furthermore, in order to prevent discoloration at high temperature drying or room temperature drying, it is possible to dry in a nitrogen gas or carbon dioxide atmosphere. Nitrogen gas and carbon dioxide gas have a large specific gravity, so the inside of the cabinet can be replaced by removing air from above the drying cabinet.

  In the apparatus of the present invention, a part of the internal air A that has been dehumidified and cooled by passing through the evaporator 5 is circulated through the bypass passage 3 that is blocked from the outside air B, and is circulated in the condenser 6 of the refrigerator. By raising the temperature a part of the air, the temperature drop of the air in the cabinet that has passed through the evaporator 5 is suppressed, and the temperature inside the cabinet is maintained at a desired temperature by the heater 7. Even when an object to be dried is dried in a relatively high temperature atmosphere, the power consumption of the heater 7 can be reduced, and an increase in running cost during high temperature drying can be suppressed.

  Then, by arranging the condenser 6 of the refrigerator across the outside air region 8 and the inside air region 3b, it is possible to avoid the complicated structure of the apparatus and the complicated control of the inside temperature. Can do. Even when the condenser 6 is divided into the outside air passage side 8 and the bypass passage side 3b, the refrigerant flows in the entire condenser in series, and there is no need to provide a branch passage or a flow rate adjusting valve in the refrigerant passage. It is possible to prevent the device structure from becoming complicated.

The block diagram of the principal part of the dehumidification dryer of this invention Sectional side view showing an embodiment of the dehumidifying dryer of the present invention Explanatory drawing which shows the example of arrangement | positioning form of a condenser Explanatory drawing which shows the other example of the arrangement | positioning form of a condenser Block diagram of the main parts of a general dehumidifying dryer The block diagram of the principal part of the dehumidifier of patent document 3

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a dehumidifying and drying apparatus according to the present invention, in which hollow arrows A and a indicate the flow of internal air, and solid arrows B indicate the flow of outside air. 5 is an evaporator of the refrigerator C, 6 is a condenser, 21 is a compressor, and 22 is an expansion valve.

  The bypass path 3 (3a, 3b, 3c) is provided in the circulation path 2 (2a, 2b, 2c) of the internal air A. The drying chamber 1, the circulation path 2 for the internal air A, and the bypass path 3 are blocked from the outside air B. The internal air A is circulated by the fan 14 via the material to be dried, the evaporator 5 of the refrigerator C, and the heater 7. A part a of the in-compartment air A that has passed through the evaporator 5 flows into the bypass passage 3a, and returns to the return passage 2b through the in-compartment air region 3b in which the condensers 6 and 6a of the refrigerator are arranged.

  The arrangement space of the condenser 6 of the refrigerator is partitioned by an airtight partition wall 10 into a region 3b where the internal air a flows and a region 8 where the outside air B flows. As shown in FIG. 3, the condenser 6 may have a structure in which an area where one condenser 6 is arranged is divided into an internal air area 3 b and an outside air area 8 by an airtight partition wall 10. As shown in FIG. 4, physically divided into two pieces 6a and 6b, and each is divided into an air region 3b and an outside air region 8 partitioned by an airtight partition wall 10, and both are separated into 3b and 8 respectively. It is also possible to cause the refrigerant to flow in series.

  FIG. 2 is a sectional side view specifically showing one embodiment of the dehumidifying and drying apparatus of the present invention. The drying cabinet 1 is provided with a turntable 11 on the floor surface, and a shelf 12 on which a material to be dried is placed is provided on the turntable. By drying the object to be dried while rotating the turntable 11, the object to be dried mounted on the shelf 12 can be uniformly dried.

  The drying cabinet 1 is partitioned by a partition wall 15 that supports the ceiling 13 and the fan 14, the upper space of the ceiling 13 is a return flow path 2 b for the internal air, and the space 2 c on the right side of the partition wall 15 is a fan 14. Inhalation space. On the opposite side of the fan 14 of the drying cabinet 1, an evaporator 5 of a refrigerator is arranged. A heater 7 is provided in the return channel 2b.

  An inflow duct 3a and an outflow duct 3c of the bypass channel are opened at a portion where the internal air passes through the evaporator 5 and flows into the return channel 2b. The internal air a flowing into the inflow duct 3a flows from the outflow duct 3c to the return flow path 2b through the internal air region 3b (see FIGS. 3 and 4) in which the condenser 6 in the refrigerator C is disposed.

  The refrigerant passing through the condenser 6 of the refrigerator C is cooled by the outside air B and the internal air a flowing through the bypass passage 3. When drying an object to be dried at an internal temperature of 30 to 50 ° C., bypass air for internal air to the extent that the refrigerant flowing through the condenser 6 is cooled at a ratio of internal air: outside air = 7: 3. It is appropriate to lead to 3. The amount of the internal air flowing through the bypass passage 3 can be adjusted by controlling the rotational speeds of the fans 9a and 9b (see FIGS. 3 and 4) on the inside and outside of the refrigerator that send cooling air to the condenser 6. The in-compartment air that has passed through the bypass passage merges with the in-compartment air that has not passed, flows through the return passage 2b, is heated by the auxiliary heater 7, and flows into the drying compartment 1 again.

  In the dehumidifying and drying apparatus according to the present invention, about 70% of the heat deprived by passing through the evaporator 5 is recovered by the internal air flowing through the bypass passage. Therefore, the temperature drop of the air in the warehouse due to passing through the evaporator 5 can be suppressed, and the interior temperature is maintained at a relatively high desired temperature with a small amount of electricity by adjusting the energization amount of the auxiliary heater 7. By using an air cooling device (refrigerator) having a low dew point temperature, the moisture content of the material to be dried can be dried to about 10%. In this case, it is possible to attach a dehumidifier to promote drying in the initial stage of drying.

  When food is dried at high temperatures, color and flavor may be impaired by oxidation. When such a problem may occur, drying may be performed by replacing the air in the drying chamber 1 with nitrogen gas or carbon dioxide gas. Since nitrogen gas and carbon dioxide gas are heavier than air, if nitrogen gas or carbon dioxide gas is slowly supplied from the bottom of the apparatus while exhausting the air inside the apparatus with the exhaust fan 16 from the ceiling of the apparatus, the air inside the apparatus is converted to nitrogen gas or carbon dioxide. Can be replaced with gas.

  Therefore, when it is desired to dry the food at a high temperature without being oxidized, the exhaust fan 16 and the lid 17 for sealing the exhaust passage provided with the exhaust fan are provided on the ceiling of the dehumidification drying apparatus, and a nitrogen cylinder is provided near the bottom of the dehumidification drying apparatus. Alternatively, a gas inlet 18 with a sealing lid connected to the carbon dioxide cylinder may be provided.

2 (2a, 2b, 2c) Circulation path 3 (3a, 3b, 3c) Bypass path 6 (6, 6a, 6b) Condenser 7 Heater 8 Outside air region 9a, 9b Cooling fan a Inside air B Outside air C Air cooling Machine

Claims (3)

A drying cabinet that accommodates an object to be dried, an air cooler that dehumidifies the air in the drying cabinet, a circulation path and a fan that circulates the air in the warehouse, and a heater provided in the circulation path, In the dehumidifying and drying apparatus for the object to be dried, the evaporator of the air cooler is arranged in the circulation path,
Dehumidification drying comprising a bypass path provided in the middle of the circulation path and an outside air passage cut off from the bypass path, and a condenser of the air cooling device is disposed across the bypass path and the outside air passage. apparatus.   Rotational speed control of a cooling fan in which the air volume of the internal air of the bypass passage for cooling the condenser of the air cooler and the air volume of the external air are respectively provided in the internal air area and the external air area of the arrangement area of the condenser The dehumidifying and drying apparatus according to claim 1, wherein the dehumidifying and drying apparatus is adjusted according to claim 1.   A sealable exhaust port provided in the upper part of the space including the circulation path and the drying cabinet, an exhaust fan installed in the exhaust port, and a sealable connection port for gas introduction provided in the lower part of the space The dehumidifying and drying apparatus according to claim 1 or 2.

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