JP3332512B2 - Cold air dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cool air dryer used for drying foods and agricultural products.

[0002]

2. Description of the Related Art Conventionally, this kind of cool air dryer has been used for drying foods, agricultural products and the like. For example, as disclosed in Japanese Patent Application No. 5-29906 filed by the applicant, the temperature inside the drying chamber is low. When the temperature becomes higher than the set temperature, it is detected by the thermostat in the drying chamber, the three-way valve is switched to the condenser side, and the high-temperature refrigerant discharged from the compressor is condensed,
The cooling operation is performed by reducing the pressure and flowing into the cooler.When the temperature falls below the set temperature, the three-way valve is switched to the reheater side, and the high-temperature refrigerant discharged from the compressor flows into the reheater and condenses. Then, the reheat operation is performed by reducing the pressure and flowing the cooler. The cooling operation and the reheating operation are repeated to dry the food.

[0003] Fig. 10 shows an internal configuration diagram of an indoor unit 101 of a conventional cool air dryer 100 according to Fig. 10. Cold air dryer 10
Reference numeral 0 denotes an indoor unit 101 mounted in a drying cabinet such as a prefabricated type, and an outdoor unit (not shown), and a so-called plate fin type in the cabinet 101K of the indoor unit 101 corresponding to the air suction port 101S at the center. A cooler 102 and a reheater 103 are provided. The cooler 102 and the reheater 103 are sequentially arranged side by side from the air suction port 101S side as shown in FIG.

Further, a blower 104 is provided in the cabinet 101K so as to correspond to the upper air discharge port 101D. When the blower 104 is operated, the air in the drying chamber is supplied to the air suction port 101S as shown by an arrow in the figure. The air was sucked in, passed through the cooler 102 and the reheater 103 sequentially, and then blown out from the air discharge port 101D through the blower 104 into the drying chamber.

[0005]

As described above, in the conventional cool air dryer 100, since the amount of air passing through the cooler 102 and the reheater 103 is the same, the capacity (heat exchange amount) of the cooler 102 The capacity (heat exchange amount) of the reheater 103 could not be changed.

FIG. 8 shows the high pressure of the refrigerant circuit during the reheating operation and the cooling operation under the condition of the outside temperature of + 32 ° C., and FIG. 9 also shows the low pressure of the refrigerant circuit. During the cooling operation, the high pressure of the condenser is determined by
It is constant at 32 ° C. and is only affected by the refrigerating capacity at the evaporation temperature determined by the internal temperature (set to an arbitrary value from + 15 ° C. to + 30 ° C.). The difference between the high pressure and the case of + 15 ° C. is about 2.5 kg / cm 2 as shown by the solid line in FIG.

On the other hand, the high pressure during the reheating operation is affected by the refrigerating capacity at the evaporating temperature determined by the reheater inlet temperature and the internal temperature (+ 15 ° C. to + 30 ° C.). The difference between the high pressure at the time of + 15 ° C. and that at the time of + 15 ° C. is also about 7 kg / cm 2 as shown by the solid line in FIG. Is consistent by design at 19 kg / square centimeter).

That is, when the internal temperature is + 15 ° C., the high pressure during the cooling operation is 16.5 kg / cm 2 (condensing temperature + 45 ° C.), and the high pressure during the reheating operation is 12 k.
g / square centimeter (condensation temperature + 32 ° C), switching from the cooling operation to the reheating operation in this state
The high pressure in the refrigerant circuit drops sharply. On the other hand, it takes time for the refrigerant liquid temperature to drop, and
During 30 minutes to 3 minutes, the refrigerant cannot be condensed and flash gas is generated. During this time, the refrigerating capacity of the cooler 102 is reduced, so that the dehumidifying capacity in the drying cabinet is reduced.

When the temperature in the refrigerator is + 30 ° C., the low pressure of the refrigerant circuit during the cooling operation (reheating operation) is 6.5 kg / cm 2 (evaporation temperature +
13 ° C.), and the load on the compressor is overloaded.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional technical problems, and has as its object to provide a cool air dryer capable of preventing a decrease in dehumidifying capacity and an overload of a compressor. I do.

[0011]

According to the present invention, there is provided a cool air dryer including a cooler, a reheater, and a blower for ventilating the cooler, a reheater, and condensing a high-temperature refrigerant discharged from a compressor. A cooling operation by flowing the high-temperature refrigerant into the reheater, and condensing the high-temperature refrigerant by flowing into the reheater; and performing a reheating operation by flowing the reduced-pressure refrigerant into the cooler. The cooler and the reheater are arranged in order in a ventilation path of the air when air is sucked in from the air suction port and blown out from the air discharge port with an interval, and the cooler and the reheater are arranged. A space between the coolers and the reheater is provided at least above the space between the cooler and the reheater, and a space above the cooler is separated from the space between the cooler and the reheater. The cooler and the reheat A single air volume adjusting means for switching between a state of isolating the space above the reheater and a state of isolating the space between the cooler and the reheater and the space above the reheater. is there.

[0012]

In the cool air dryer 1 of the present invention, since the air volume adjusting means for adjusting the air volume passing through the cooler and the reheater is provided, when the temperature in the refrigerator is low, the air passes through the reheater by the air volume adjusting device. By reducing the amount of air, the high-pressure pressure during the reheating operation can be increased. As a result, it is possible to reduce the high pressure drop when switching from the cooling operation to the reheating operation, reduce the flash gas generation time, and improve the dehumidifying ability of the cooler.

In addition, when the temperature in the refrigerator is high, the amount of air passing through the cooler is reduced by the air volume adjusting means, so that the low pressure during cooling and reheating can be reduced. Thereby, the load on the compressor can be reduced.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view of an indoor unit 2 of the cool air dryer 1 of the present invention, FIG. 2 is an internal configuration diagram of the indoor unit 2 of the cool air dryer 1, and FIG. 3 is a refrigerant circuit diagram of the cool air dryer 1. . The cool air dryer 1 includes an indoor unit 2 mounted in a drying cabinet 3 of a prefabricated type or the like, and an outdoor unit 4, and a so-called plate corresponding to the air suction port 2S at the center in the cabinet 2K of the indoor unit 2. A fin type cooler 21 and a reheater 23 are provided.

The cooler 21 and the reheater 23 are sequentially arranged side by side from the air suction port 2S via a space 63, and a space 61 is formed above them. This cooler 21
In a space 61 corresponding to a space 63 above the space 63 between the heat exchanger 23 and the reheater 23, a flow rate adjusting bracket 62 having a substantially L-shaped cross section as a flow rate adjusting means.
Is rotatably mounted. By rotating the air volume adjusting bracket 62, in a state where the top of the L-shape corresponds to the upper end of the cooler 21 as shown in FIG.
3 and the space 61 above the cooler 21 are isolated, and the space 63 and the space 61 above the reheater 23 are communicated. When the apex of the L-shape is directed upward as shown in FIG. 6, the space 63 and the space 61 above the cooler 21 and the reheater 23 are both separated. Further, in a state where the apex of the L-shape corresponds to the upper end of the reheater 23 as shown in FIG. 7, the space 63 and the space 61 above the reheater 23 are isolated, and the space 63 and the space 61 above the cooler 21 are separated. Communication.

On the other hand, a blower 26 is provided in the cabinet 2K so as to correspond to the upper air discharge port 2D. When the blower 26 is operated, the air in the drying chamber 3 is supplied to the air suction port as shown by the arrow in the figure. After being sucked in from the 2S and sequentially passing through the cooler 21 and the reheater 23, the air is blown into the drying chamber 3 from the air discharge port 2D via the blower 26.

Next, in the refrigerant circuit of FIG. 3, a three-way valve 7 is connected to a discharge side of a compressor 6 provided on the indoor unit 2 side, and one outlet of the three-way valve 7 is connected to the outdoor unit 4.
Is connected to the condenser 8 provided in the first stage. 9 is a condenser 8
This is a blower for forced air cooling.

The compressor 6 is, for example, a scroll compressor as disclosed in Japanese Patent Application No. 4-5612 filed by the applicant of the present invention. Circuit 11 is attached. The capacity control circuit 11 communicates the discharge side and the suction side of the compressor 6 before the three-way valve 7 by a thin tube including on-off valves 12 and 13 and a check valve 14 connected in series. Further, a portion between the on-off valves 12 and 13 is connected to a scroll of the compressor 6. On-off valve 12
Is open and the on-off valve 13 is closed, the operating capacity is 100%. When the on-off valve 12 is closed and the on-off valve 13 is open, the operating capacity is reduced by about 40% (to about 60%).

The condenser 8 is connected to a receiver 17 via a check valve 16 provided on the drying cabinet 3 side, and the receiver 17 is connected to a cooler 21 via an expansion valve 19. Cooler 2
Numeral 1 is connected to the suction side of the compressor 6 via an accumulator 22 to form an annular refrigeration cycle. The expansion valve 1
9 detects the temperature on the outlet side of the cooler 21 and adjusts the opening degree so as to maintain the degree of superheat at a predetermined value.

The other outlet of the three-way valve 7 is connected to a reheater 23, which is connected to the liquid receiver 17 via a check valve 24. Each of the check valve 24 and the check valve 16 has the liquid receiver 17 side directed forward.

A defrost circuit 27 is connected to the discharge side of the compressor 6 before the three-way valve 7. The defrost circuit 27 is connected between the expansion valve 19 and the cooler 21 via an on-off valve 28 and a capillary tube 29. It is connected to the. The on-off valve 28 detects the temperature on the outlet side of the cooler 21 and opens and closes the defrost circuit 27 (indicated by * 2 in the figure). The three-way valve 7 is controlled by a control circuit 31 constituting a capacity control device (indicated by * 1 in the figure), and the control circuit 31 controls the on-off valves 12 and 13 (* 3 and * in the figure). * 4), a thermostat 32 for detecting the temperature in the refrigerator, a thermostat 33 for detecting the temperature in the refrigerator for controlling the three-way valve 7, and a humistat 34 for detecting the humidity in the refrigerator. I have.

A liquid injection circuit 38 having an on-off valve 36 and a thermo valve 37 is connected to the compressor 6 from the outlet of the liquid receiver 17. Reference numeral 39 denotes an on-off valve, and 41 denotes a liquid solenoid valve, which is always open. Furthermore,
Reference numerals 42, 43, and 44 denote a dryer, an indicator, and a strainer, respectively. Reference numeral 46 denotes an oil control circuit that returns lubricating oil to the compressor 6.

Next, the operation of the cool-air dryer 1 of the present invention having the above-described configuration will be described. The cold air dryer 1 has an internal temperature of, for example, +1.
The temperature is used in the range of 5 ° C. to + 30 ° C., and the control circuit 31 is set to an arbitrary temperature within the range of + 15 ° C. to + 30 ° C. Here, the internal temperature + 23 ° C
Is set, and the set value of the internal temperature is +2.
In the case of 0 ° C. to + 25 ° C., the air volume adjusting fitting 62 is in the state shown in FIG. Then, the control circuit 31 operates the compressor 6, and sets the flow path of the three-way valve 7 to the one outlet direction until the internal temperature decreases to the set temperature.

As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 6 enters the condenser 8 through the three-way valve 7 as shown by the arrow in FIG. Then, the liquid enters the liquid receiver 17 and reaches the expansion valve 19 through the liquid electromagnetic valve 41. The opening of the expansion valve 19 is adjusted based on the outlet temperature of the cooler 21 as described above, and the condensed and liquefied refrigerant is throttled and supplied to the cooler 21. The refrigerant flowing into the cooler 21 evaporates, absorbs heat from the surroundings to exhibit a cooling function, and is then sucked into the compressor 6 via the accumulator 22.

By the cooling operation, the temperature in the refrigerator becomes, for example, +
When the temperature has dropped to 25 ° C., the control circuit 31 detects this based on the thermostat 32,
3 to perform a capacity control operation for reducing the operating capacity of the compressor 6 to 60%. By the capacity control operation of the compressor 6, the rate of decrease in the internal temperature becomes slow.

Then, the internal temperature is set to the set temperature (+23).
° C), the control circuit 31 detects this based on the thermostat 33, and sets the flow path of the three-way valve 7 to the other outlet direction. Thereby, the high-temperature and high-pressure gas refrigerant discharged from the compressor 6 enters the reheater 23 through the three-way valve 7 as shown by the arrow in FIG. On the other hand, the refrigerant is condensed there, enters the receiver 17 via the check valve 24, and thereafter flows as described above.

When the temperature inside the refrigerator rises to a predetermined upper limit value (a value set with a predetermined hysteresis width above + 23 ° C.) by the reheating operation, the control circuit 31 returns to the cooling operation of FIG. After that, the cooling operation and the reheating operation are repeated. All the air sucked in by the blower 26 passes through the cooler 21 and the reheater 23 as shown by arrows in FIG. 6, and is cooled by the cooler 21 and the air heated by the reheater 23 is shown by arrows in FIG. As shown in the figure, the articles are circulated in the refrigerator, and the articles stored in the refrigerator are dried by repeating the cooling / reheating operation.

By the way, the temperature inside the refrigerator is + 15 ° C. to + 20 ° C.
(For example, at + 15 ° C.), the air volume adjustment fitting 62 is set to the state shown in FIG. As a result, a part of the air entering the reheater 23 after passing through the cooler 21 flows through the interval 61 and bypasses the reheater 23, so that the heat of the reheater 23 during the reheat operation is reduced. The exchange rate decreases, and the high pressure of the refrigerant circuit increases as shown by the broken line in FIG. 8 to about 14 kg / cm 2.

Therefore, the pressure difference when the operation is switched from the cooling operation to the reheating operation is reduced, and the flash gas generation time after the switching is about 1 minute to 1 minute and 10 seconds. That is,
Since the flash gas generation time is reduced to about 40% of the conventional time, the dehumidifying ability of the cooler 21 is improved.

On the other hand, when the internal temperature is set in the range of + 25 ° C. to + 30 ° C. (for example, + 30 ° C.), the air volume adjusting fitting 62 is brought into the state shown in FIG. As a result, a part of the air sucked from the air suction port 2S and entering the cooler 21 flows through the space 61 and bypasses the cooler 21, so that the cooler 21 during the cooling (reheating) operation is operated. , The low pressure of the refrigerant circuit decreases as shown by the broken line in FIG. 9 to about 5.5 kg / cm 2 (evaporation temperature + 8 ° C.). Therefore, the load on the compressor 6 is reduced.

[0031]

As described above in detail, according to the present invention, since the air volume adjusting means for adjusting the air volume passing through the cooler and the reheater is provided, when the temperature in the refrigerator is low, the air volume adjusting device controls the air volume. By reducing the amount of air passing through the heater, the high pressure during the reheating operation can be increased. As a result, it is possible to reduce the pressure drop of the high pressure when switching from the cooling operation to the reheating operation, reduce the flash gas generation time, and improve the dehumidifying ability of the cooler.

When the temperature inside the refrigerator is high, the amount of air passing through the cooler is reduced by the air volume adjusting means, so that the low pressure during cooling and reheating can be reduced. Thereby, the load on the compressor can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of an indoor unit of a cool air dryer of the present invention.

FIG. 2 is an internal configuration diagram of an indoor unit of the cool air dryer of the present invention.

FIG. 3 is a refrigerant circuit diagram showing a flow of a refrigerant during a cooling operation of the cool air dryer of the present invention.

FIG. 4 is a refrigerant circuit diagram showing the flow of the refrigerant during the reheating operation of the cool air dryer of the present invention.

FIG. 5 is a diagram showing a state of an air volume adjusting fitting of the cool air dryer of the present invention and an air flow in that case.

FIG. 6 is a view showing the state of the air volume adjusting fitting of the cold air dryer of the present invention and the flow of air in that case.

FIG. 7 is a view showing the state of the air volume adjusting fitting of the cool air dryer of the present invention and the flow of air in that case.

FIG. 8 is a diagram showing the relationship between the internal temperature of the cold air dryer and the high pressure.

FIG. 9 is a diagram showing the relationship between the internal temperature of the cold air dryer and the low pressure.

FIG. 10 is an internal configuration diagram of an indoor unit of a conventional cool air dryer.

FIG. 11 is a diagram showing a flow of air flowing through a cooler and a reheater of a conventional cool air dryer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cold-air dryer 6 Compressor 7 Three-way valve 8 Condenser 19 Expansion valve 21 Cooler 23 Reheater 26 Blower 61 Interval 62 Airflow adjusting bracket (airflow adjusting means)

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F26B 21/00 F25B 29/00 A23L 3/40

Claims (1)

(57) [Claims] A cooling operation is provided by providing a cooler, a reheater, and a blower for ventilating these, and condensing a high-temperature refrigerant discharged from a compressor, reducing the pressure of the high-temperature refrigerant, and flowing the refrigerant into the cooler. , and condensed allowed to flow into the high-temperature refrigerant to said reheater, the cold air drying machine to perform reheating operation by flowing into the cooler under reduced pressure, by the blower
Air is sucked in from the air inlet and blows out from the air outlet
The cooler and the reheater in the air passage when
Are arranged in order with an interval, and the cooler and the front
Provide a space for air flow above the reheater, at least
The distance between the cooler and the reheater and above the cooler
The cooling device and the reheating device
And the spacing above the cooler and the reheater,
Condition between the cooler and the reheater
Cut off the condition that separates the space from the space above the reheater.
A cool air dryer having a single air volume adjusting means for changing .