Combined drying and refrigerating storehouse

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates, in general, to a combined drying and refrigerating storehouse and, more particularly, to a combined drying and refrigerating storehouse using a heat pump unit.

2. Description of the Prior Art

As well known to those skilled in the art, a drying technique has been generally utilized to easily store and transport agricultural, marine or livestock products, and a refrigeration or freezing technique has been generally utilized to maintain the freshness of the agricultural, marine or livestock products.

In general, the agricultural, marine or livestock products are stored in the refrigerating storehouse after the products are dried. Accordingly, the products are transported to and stored in the refrigerating storehouse after the products are dried, so that the treatment and transportation costs of the products become expensive.

Japanese Patent Publication No. Sho 50-16022 discloses a combined drying and refrigerating storehouse for reducing the treatment and transportation costs. In this combined drying apparatus and refrigerating storehouse, the unitized principal parts of the drying and refrigerating apparatus are mounted on one side of a dry and refrigerating chamber, and the unit is fabricated by disposing an air-cooled condenser and a water-cooled condenser in parallel between a compressor and an evaporator. For a drying operation, high temperature and high pressure coolant gas is condensed in the water-cooled condenser, and indoor air is dehumidified and cooled by the evaporator, heated by the water-cooled condenser and circulated through the drying and refrigerating chamber by its blower, thereby allowing articles to be dried. On the other hand, for a refrigerating operation, the temperature of the drying and refrigerating chamber is lowered by the water-cooled condenser and the evaporator after the drying of the articles is completed, thereby allowing articles to be refrigerated.

However, in this conventional combined drying apparatus and refrigerating storehouse, since the water-cooled condenser is formed separately to condense coolant gas, the compressed coolant liquid is dehumidified and cooled in the evaporator and, thereafter, the dehumidified and cooled coolant is heated in the air-cooled condenser, its construction is complicated and the time period for drying articles in the storehouse is lengthened owing to difficulty in increasing the temperature of drying air.

In order to overcome the problems, the inventor of the present invention proposed a combined drying apparatus and refrigerating storehouse in Korean Patent No. 226679. In this combined drying apparatus and refrigerating storehouse, a exhaustion chamber, a circulation passage and a drying and refrigerating chamber are formed one after another in a housing, an outdoor heat exchanger and an indoor heat exchanger are respectively mounted on the sidewall of the exhaustion chamber and under the partition plate of the drying and refrigerating chamber, thus forming a closed circulation pass that is positioned between the circulation passage and the drying and refrigerating chamber and passes through the heat exchangers, dampers are mounted on the partition plate of the exhaustion chamber, and ambient air preheating means communicating with the exhaustion chamber is disposed on the upper portion of the housing, thereby performing drying and refrigerating operations effectively,

This combined drying apparatus and refrigerating storehouse has advantages in which drying air is circulated and a dehumidifying operation is performed easily, drying efficiency is increased by the promotion of the gasification of coolant liquid, and the dried articles can be refrigerated without being removed. However, this combined drying apparatus and refrigerating storehouse has shortcomings in which a first group of articles must be removed to another refrigerating chamber when a second group of articles are desired to be dried while the first group of articles are refrigerated in the storehouse and a third group of articles must be completely dried and removed to another place when a fourth group of articles are desired to be refrigerated while the third group of articles are dried in the storehouse because drying and refrigerating operations can be performed selectively, thereby increasing the treatment time period and treatment cost for the articles.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a combined drying apparatus and refrigerating storehouse, which is capable of rapidly drying and refrigerating agricultural, marine or livestock products at the same time and easily performing the ventilation of its drying chamber and the defrosting of its refrigerating chamber.

In order to accomplish the above object, the present invention provides a combined drying and refrigerating storehouse, comprising: a housing having a heat pump unit chamber at its central portion and two combined drying and refrigerating chambers at its side portions, the heat pump unit chamber being divided from the combined drying and refrigerating chambers by two partition walls; two circulating chambers extended outwardly from the partition walls and extended vertically, the circulating chambers respectively communicating with the upper and lower portions of the combined drying and refrigerating chambers and having blowers at their lower portions; a heat pump unit having a compressor, a four-way valve, first and second heat exchangers and a second condenser, the compressor, the four-way valve, the first heat exchanger, the second condenser, the second heat exchanger and the compressor being connected one after another by means of a first conduit, the outlet of the four-way valve being connected to the inlet of the compressor by means of a suction conduit, the compressor, the four-way valve and the second condenser being disposed in the heat pump unit chamber and the first and second heat exchangers being disposed in upper portions of the circulation chambers; a second evaporator disposed on a portion of a second conduit, the second conduit connecting the second condenser to a point on the output-side portion of the first conduit with regard to the second heat exchanger functioning as an evaporator; means for controlling a flow passage of coolant, the flow passage control means being disposed on the first and second conduits; and a control unit for controlling the four-way valve, the flow passage control means, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1

is a cross section showing a combined drying and refrigerating storehouse in accordance with a preferred embodiment of the present invention;

FIG. 2

is a cross section showing a state where a heat piping is mounted;

FIG. 3

is a block diagram showing a control-related construction for the combined drying and refrigerating storehouse; and

FIG. 4

is a diagram showing a control unit for the combined drying and refrigerating storehouse.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As illustrated in

FIG. 1

, a combined drying and refrigerating storehouse according to the present invention comprises a housing

1

and a heat pump unit

2

that is mounted in the housing

1

.

In the housing

1

, a heat pump unit chamber

3

opened to the atmosphere is formed on the central portion of the interior of the housing

1

, two combined drying and refrigerating chambers A and B (will be referred to as “chamber A” and “chamber B”) are respectively formed on the side portions of the interior of the housing

1

, and two circulation passages

5

and

5

′ respectively communicating with the upper and lower portions of the chambers A and B are respectively formed between the heat pump unit chamber

3

and the chamber A and between the heat pump unit chamber

3

and the chamber B. The heat pump unit chamber

3

is divided from the two circulation passages

5

and

5

′ by means of partition walls

4

and

4

′.

The circulation passages

5

and

5

′ are respectively divided into upper passages and lower passages

7

and

7

′ by partition plates

6

and

6

′. Two blowers

8

and

8

′ are respectively mounted in the lower passages

7

and

7

′. Two dampers

9

and

10

are respectively mounted on the upper and lower portion of the partition wall

4

, two dampers

12

and

13

are respectively mounted on the upper and lower portions of the partition wall

4

′, and two dampers

11

and

14

are respectively mounted on the partition plates

6

and

6

′. Two temperature sensors

15

and

15

′ are respectively disposed in the chambers A and B.

In the heat pump unit, a compressor

16

, a four-way valve

17

and a second condenser

20

are disposed in the heat pump unit chamber

3

, and a first heat exchanger

18

and a second heat exchanger

19

are respectively disposed in the upper portions of the circulation passages

5

and

5

′. The compressor

16

, the four-way valve

17

, the first and second heat exchangers

18

and

19

and the compressor

16

are connected one after another by means of a first conduit

21

, and the outlet of the four-way valve

17

is connected to the inlet of the compressor

16

by means of a suction conduit

22

. Accordingly, the first heat exchanger

18

functions as a condenser and the second heat exchanger

19

functions as an evaporator when the chamber A functions as a refrigerating chamber and the chamber B functions as a drying chamber, whereas the functions of the first and second heat exchangers

18

and

19

are changed when the functions of the chambers A and B are changed. In order to evaporate coolant liquid while the coolant liquid condensed in the second condenser

20

is bypassed to the compressor

16

without passing through the first and second heat exchangers

18

and

19

, a point on the output-side portion of the first conduit

21

with regard to the second heat exchanger

19

functioning as an evaporator is connected to the second condenser

20

by a second conduit

24

, a second evaporator

23

is disposed on the portion of the second conduit

24

passing through the heat pump unit chamber

3

, and a point on the input-side portion of the first conduit

21

with regard to the first heat exchanger

18

functioning as a condenser is connected to a point on the second conduit

24

by a third conduit

25

. When the first heat exchanger

18

functions as a condenser, low temperature and low pressure coolant gas evaporated in the second evaporator

23

passes through the second conduit

24

and enters the compressor

16

through the four-way valve

17

and the suction conduit

22

; whereas when the second heat exchanger

19

functions as an condenser, low temperature and low pressure coolant gas evaporated in the second evaporator

23

passes through the third conduit

25

and enters the compressor

16

through the four-way valve

17

and the suction conduit

22

.

Flow passage control means comprised of solenoid valves for changing the flow passage of coolant is disposed on the first and second conduits

21

and

24

. That is, a first solenoid valve

31

is disposed on the portion of the first conduit

21

between the second heat exchanger

19

and the second condenser

20

, a second solenoid valve

32

is disposed on a first bypass

26

around the first solenoid valve

31

, a third solenoid valve

33

is disposed on the portion of the first conduit

21

between the first heat exchanger

18

and the second condenser

20

, a fourth solenoid valve

34

is disposed on a second bypass

27

around the third solenoid valve

33

, a fifth solenoid valve

35

is disposed on the portion of the second conduit

24

between the second condenser

20

and the second evaporator

23

, and a sixth solenoid valve

36

on a third bypass

28

connecting the second bypass

27

with the input-side portion of the second conduit

24

with regard to the second evaporator

23

. A first expansion valve

19

is disposed on the input-side portion of the first conduit

21

with regard to the second heat exchanger

19

functioning as an evaporator, a second expansion valve

20

is disposed on the input-side portion of the first conduit

21

with regard to the first heat exchanger

18

functioning as a evaporator, and a third expansion valve

42

is disposed on the input-side portion of the second conduit

24

with regard to the second evaporator

23

.

As depicted in

FIG. 3

, the combined drying and refrigerating storehouse of the present invention comprises a control unit

50

. The control unit

50

selectively operates the four-way valve

17

, the defrosting heaters

18

′ and

19

′, the six solenoid valves

31

to

36

, and the dampers

9

to

14

, in response to an output signal of the temperature sensors

15

and

15

′, the timers

29

and

29

′, and the switches

37

,

38

and

39

.

As illustrated in

FIG. 4

, the control unit

50

comprises a compressor relay

16

′ connected in series to a switch relay

51

having first and second contacts

54

and

55

. A four-way valve relay

17

′ is connected to the second contact

55

so that the flow passage of coolant can be changed when the second contact

55

becomes ON.

A temperature sensor relay

56

, a timer relay

57

, a defrosting heater relay

58

and solenoid valve relays

32

′,

33

′ and

35

′ are connected in parallel to the first contact

54

of the switch relay

51

via auxiliary relays

59

and

60

, a timer relay contact

63

and auxiliary relays

64

and

65

. A temperature sensor relay

56

′, a timer relay

57

′, a defrosting heater relay

58

′ and solenoid valve relays

31

′,

34

′ and

36

′ are connected in parallel to the second contact

55

of the switch relay

51

via auxiliary relays

61

and

62

, a timer relay contact

63

′ and auxiliary relays

66

and

67

. A second relay evaporator relay

23

′ that is operated in response to a relay signal of the temperature sensor relays

56

and

56

′ or timer relays

57

and

57

′ is connected in parallel to a compressor relay

16

′, first and second damper relays

68

and

69

are respectively connected to first and second switch relays

52

and

53

connected in parallel to the compressor relay

16

′, and simultaneously the contacts

70

of the first damper relay contact

68

are respectively connected to damper auxiliary relays

9

′,

10

′ and

11

′ and the contacts

71

of the second damper relay contact

69

are respectively connected to damper auxiliary relays

12

′,

13

′ and

14

′.

The damper auxiliary relays

9

′ to

14

40

may be classified into one group of first, second and third damper auxiliary relays

9

′,

10

′ and

11

′ connected to the first damper relay contact

70

in series and another group of fourth, fifth and sixth damper auxiliary relays

12

′,

13

′ and

14

40

connected to the second damper relay contact

71

in series. The first and second switch relays

52

and

53

used to operate the damper auxiliary relays

9

′ to

12

40

may be replaced with timer relays or humidity sensor relays.

The housing

1

may preferably be fabricated in the form of a portable container for the convenience of movement. For example, in the case of a 40-foot housing, the chamber B is integrated with the heat pump unit chamber

3

into a single body, the chamber A is formed larger than the chamber B, they are moved to a place where a combined drying and refrigerating storehouse is installed, and, thereafter, the combined drying and refrigerating storehouse is completed by connecting their conduits to one another. In this case, the relatively large chamber A is preferably used as a refrigerating chamber.

As depicted in

FIG. 1

, two groups of heat piping

75

are respectively disposed on the portions of the first conduit

21

passing through the chambers A and B. As illustrated in

FIG. 2

, the heat piping

75

comprises an evaporating portion

76

surrounding the first conduit

21

, a plurality of condensing portions

77

vertically mounted to communicate with the evaporating portion

76

, and working fluid

78

, such as distilled water, alcohol, liquid ammonia or the like, filling the interiors of the evaporating portion

76

and the condensing portions

77

. In the heat piping

75

, there is reiterated a cycle in which the working fluid

78

is evaporated in the evaporating portion

76

by means of the heat possessed by the coolant flowing through the first conduit

21

, the evaporated working fluid

78

ascends to the evaporating portion

77

and is condensed in the evaporating portion

77

, and, thereafter, the condensed working fluid

78

descends back to the evaporating portion

76

. Additionally, a far-infrared ray radiating film

79

is formed on the exterior surface of the heat piping

75

, so that the heat piping

75

radiates far-infrared rays to articles desired to be dried and refrigerated.

Dehumidifying agents

80

made of diatomaceous earth, zeolite, silica, alumina or the like are positioned on the upper portions of the chambers A and B.

Reference numeral

81

designates an exhaustion fan.

In the combined drying and refrigerating storehouse of the present invention, before a drying operation and a refrigerating operation are performed at the same time in the chambers A and B, the blowers

8

and

8

′ and the compressor

16

are operated by the manipulation of a switch (not shown) and the abnormal pressure in the compressor

16

is examined. When abnormality does not exist, the operations are initiated by manipulating the switch

37

. At this time, the third damper

11

and the sixth damper

14

are kept open. Hereinafter, the operations of the combined drying and refrigerating storehouse are described.

1. Refrigerating Operation in Chamber A and Drying Operation in Chamber B

As the first contact

54

of the switch relay

51

is rendered to be ON by the manipulation of the switch

37

, the third solenoid valve relay

33

′ becomes ON to open the third solenoid valve

33

, the four-way valve relay

17

′ becomes OFF to maintain the four-way valve

17

in a state where the four-way valve

17

allows the coolant to flow toward the chamber A through the chamber B, the fifth solenoid valve relay

35

′ becomes OFF by means of the first auxiliary relay

59

and the first auxiliary relay contact

64

to close the fifth solenoid valve

35

, and the second solenoid valve relay

32

′ becomes ON by means of the first auxiliary relay contact

64

to open the second solenoid valve

32

.

Preparation for the operations is performed in such a way that the temperature sensor relay

56

is rendered to be ON as the temperature sensor

15

begins to take temperatures, and the timer

29

disposed in the chamber A sets a defrosting time period for the second heat exchanger

19

by means of the timer relay

57

. At this time, the set value of the temperature sensor

15

is different depending upon the kinds of articles stored in the chamber A.

As the first contact

54

is rendered to be ON by the manipulation of the switch

37

, there is reiterated a cycle in which coolant is compressed into high temperature and high pressure coolant gas in the compressor

16

, passes through the four-way valve

17

and the heat piping

75

of the chamber B and performs the drying operation in the chamber B by means of condensation heat while being condensed in the first heat exchanger

18

functioning as a condenser, the condensed coolant liquid passes through the third solenoid valve

33

and is completely condensed by means of the reduction of temperature while being secondly condensed in the second condenser

20

, the completely condensed coolant liquid passes through the second solenoid valve

32

, is expanded in the first expansion valve

40

and performs the refrigerating operation in the chamber A by means of its evaporation heat while being evaporated in the second heat exchanger

19

, and the evaporated coolant gas of low temperature and low pressure passes through the heat piping

75

of the chamber A and enters the compressor

16

through the four-way valve

17

and the suction conduit

22

.

The third and sixth dampers

11

and

14

are kept open and the blowers

8

and

8

′ are operated while the refrigerating and drying operations are respectively performed in the chambers A and B, so that air in the chambers A and B are circulated through the circulation passages

5

and

5

′, thus allowing the drying and refrigerating operations to be well performed.

While the drying and refrigerating operations are performed, the working fluid

78

is evaporated in the evaporating portion

76

by means of the heat possessed by the coolant flowing through the first conduit

21

, the evaporated working fluid

78

ascends to the evaporating portion

77

and is condensed in the evaporating portion

77

, and, thereafter, the condensed working fluid

78

descends back to the evaporating portion

76

. When the working fluid

78

is condensed in the evaporating portion

77

, the working fluid

78

radiates condensation heat and simultaneously far-infrared rays are radiated from a far-infrared ray radiating film

79

formed on the exterior surface of the heat piping

75

. Since the far-infrared rays are radiated to the articles desired to be dried or radiated, the articles desired to be dried are dried uniformly and sufficiently and the articles desired to be refrigerated are kept fresh.

In the meantime, a portion of circulated air is automatically dehumidified by the dehumidifying agent

80

.

As the switch relay

53

is rendered to be ON by the manipulation of the switch

39

, the sixth damper

14

is closed by means of the second damper relay contact

71

and the sixth damper auxiliary relay

14

′, and the fourth damper

12

and the fifth damper

13

are respectively opened by means of the fourth damper auxiliary relay

12

40

and the fifth damper auxiliary relay

13

′. Accordingly, the chamber B is ventilated, so that the circulation air is dehumidified, thus shortening the time period for the drying operation.

2. Refrigerating and Defrosting Operations in Chamber A

When the temperature of the chamber A falls on or below the set value while the refrigerating operation is performed in the chamber A and the drying operation is performed in the chamber B as described above, the temperature sensor

15

renders the temperature sensor relay

56

to be OFF, thereby closing the second solenoid valve

32

through the second solenoid valve relay

32

′ by means of the first auxiliary relay

59

and the first auxiliary relay contact

64

, and opening the fifth solenoid valve

35

through the fifth solenoid valve relay

35

′ by the first auxiliary relay contact

64

and simultaneously allowing the second evaporator

23

to be operated by means of the second evaporator relay

23

′. On the one hand, coolant liquid flowing out of the second condenser

20

does not flow into the second heat exchanger

19

and accordingly the operation of the second heat exchanger

19

is stopped, so that the refrigeration temperature of the chamber A is adjusted. On the other hand, the coolant liquid flowing out of the second condenser

20

passes through the fifth solenoid valve

35

of the second conduit

24

and is expanded in the third expansion valve

42

, the expanded coolant liquid is evaporated into low temperature and low pressure coolant gas in the second evaporator

23

, and the low temperature and low pressure coolant gas passes through the second conduit

24

and the first conduit

21

and enters the compressor

16

through the four-way valve

17

and the suction conduit

22

. The air of the heat pump unit chamber

3

cooled by the second evaporator

23

is exhausted out of the housing

1

by means of the exhaustion fan

81

. If the chamber B is ventilated by the opening of the fourth and fifth dampers

12

and

13

while the air in the heat pump unit chamber

3

is exhausted to the outside as described above, the waste heat in the chamber B is supplied to the second evaporator

23

, and so the evaporation of coolant liquid is performed well in the second evaporator

23

. Accordingly, superior drying capacity can be maintained when the temperature of the ambient air is low, and thermal efficiency can be improved by the utilization of the waste heat.

When the temperature of the chamber A rises above the set value from the above-described state, the temperature sensor

15

renders the temperature sensor relay

56

to be ON, thereby closing the fifth solenoid valve

35

through the fifth solenoid valve relay

35

′ by means of the first auxiliary relay

59

and the first auxiliary relay contact

64

, and opening the second solenoid valve

32

through the second solenoid valve relay

32

′ by the first auxiliary relay contact

64

and simultaneously stopping the second evaporator

23

from being operated by means of the second evaporator relay

23

′. Accordingly, the operation of the second heat exchanger

19

is restored, and so the refrigeration operation in the chamber A is continued.

Meanwhile, when the set time period of the timer

29

, which is operated as soon as the temperature sensor

15

begins to take a temperature, terminates, the timer

29

opens the fifth solenoid valve

35

through the fifth solenoid valve relay

35

′ using the second auxiliary relay

60

and the second relay contact

65

through the timer relay

57

and the timer relay contact

63

, closes the second solenoid valve

32

through the second solenoid valve relay

32

′ by means of the second auxiliary relay contact

65

, and allows the second evaporator

23

to be operated by means of the defrosting heater contact

72

and the second evaporator relay

23

′ and simultaneously operates the defrosting heater

19

′ disposed under the second heat exchanger

19

by means of the timer relay contact

63

and the defrosting heater relay

58

(the operation of second heat exchanger

19

is automatically stopped).

While the second heat exchanger

19

is defrosted by the defrosting heater

19

′, coolant liquid flowing out of the second condenser

20

is expanded in the third expansion valve

42

and evaporated into low temperature and low pressure coolant gas in the second evaporator

23

, and the evaporated coolant gas passes through the second conduit

24

and the first conduit

21

and enters the compressor

16

through the four-way valve

17

and the suction conduit

22

.

When the defrosting operation has been performed for the set defrosting time period, the timer

29

stops the defrosting heater

19

′ by means of the timer relay

57

and the timer relay contact

63

, closes the fifth solenoid valve

35

through the fifth solenoid valve relay

35

′ using the second auxiliary relay

60

and the second auxiliary relay contact

65

through the timer relay contact

63

, opens the second solenoid valve

32

through the second solenoid valve relay

32

′ by means of the second auxiliary relay contact

65

, and stops the second evaporator

23

from being operated by means of the defrosting heater contact

72

and the second evaporator relay

23

′. Additionally, as soon as the second evaporator

23

is stopped from being operated, the second heat exchanger

19

is automatically operated, so that the refrigerating operation in the chamber A is continued.

3. Refrigerating Operation in Chamber B and Drying Operation in Chamber A

As the second contact

55

of the switch relay

51

is rendered to be ON by the manipulation of the switch

37

, the first solenoid valve relay

31

′ becomes ON to open the first solenoid valve

31

, the four-way valve relay

17

′ becomes ON to manipulate the four-way valve

17

to a state where the four-way valve

17

allows the coolant to flow toward the chamber B through the chamber A, the fourth solenoid valve relay

34

′ becomes ON by means of the third auxiliary relay

61

and the third auxiliary relay contact

66

to open the fourth solenoid valve

34

, and the sixth solenoid valve relay

36

′ becomes OFF by means of the third auxiliary relay contact

66

to close the sixth solenoid valve

36

. Meanwhile, preparation for the operations is performed in such a way that the temperature sensor relay

56

′ is rendered to be ON as the temperature sensor

15

′ begins to take temperatures, and the timer

29

′ disposed in the chamber B sets a defrosting time period for the first heat exchanger

18

by means of the timer relay

57

′. At this time, the set value of the temperature sensor

15

′ is different depending upon the kinds of articles stored in the chamber B.

As the second contact

55

is rendered to be ON by the manipulation of the switch

37

, there is reiterated a cycle in which coolant is compressed into high temperature and high pressure coolant gas in the compressor

16

, passes through the four-way valve

17

and the heat piping

75

of the chamber A and performs the drying operation in the chamber A by means of condensation heat while being condensed in the second heat exchanger

19

functioning as a condenser, the condensed coolant liquid passes through the first solenoid valve

31

and is completely condensed by means of the reduction of temperature while being secondly condensed in the second condenser

20

, the completely condensed coolant liquid passes through the fourth solenoid valve

34

, is expanded in the second expansion valve

41

and performs the refrigerating operation in the chamber B by means of its evaporation heat while being evaporated in the first heat exchanger

18

, and the evaporated coolant gas of low temperature and low pressure passes through the heat piping

75

of the chamber B and enters the compressor

16

through the four-way valve

17

and the suction conduit

22

.

The third and sixth dampers

11

and

14

are kept open and the blowers

8

and

8

′ are operated while the drying and refrigerating operations are respectively performed in the chambers A and B, so that air in the chambers A and B are circulated through the circulation passages

5

and

5

′, thus allowing the drying and refrigerating operations to be well performed.

While the drying and refrigerating operations are respectively performed in the chambers A and B, the heat piping

75

and the dehumidifying agent

80

perform the same function as that of the case where the refrigerating and drying operations are respectively performed in the chambers A and B.

As the switch relay

52

is rendered to be ON by the manipulation of the switch

38

, the third damper

11

is closed by means of the first damper relay contact

70

and the third damper auxiliary relay

11

′, and the first damper

9

and the second damper

10

are respectively opened by means of the first damper auxiliary relay

9

′ and the second damper auxiliary relay

10

′. Accordingly, the chamber A is ventilated, so that the circulation air is dehumidified, thus shortening the time period for the drying operation.

4. Refrigeration and Defrosting Operations in Chamber B

When the temperature of the chamber B falls on or below the set value while the drying operation is performed in the chamber A and the refrigerating operation is performed in the chamber B as described above, the temperature sensor

15

′ renders the temperature sensor relay

56

′ to be OFF, thereby closing the fourth solenoid valve

34

through the fourth solenoid valve relay

34

′ by means of the third auxiliary relay

61

and the third auxiliary relay contact

66

, and opening the sixth solenoid valve

36

through the sixth solenoid valve relay

36

′ by the third auxiliary relay contact

66

and simultaneously allowing the second evaporator

23

to be operated by means of the second evaporator relay

23

′. On the one hand, coolant liquid flowing out of the second condenser

20

does not flow into the first heat exchanger

18

and accordingly the operation of the third heat exchanger

18

is stopped, so that the refrigeration temperature of the chamber B is adjusted. On the other hand, the coolant liquid compressed in the second condenser

20

passes through the sixth solenoid valve

36

of the third bypass

28

and is expanded in the third expansion valve

42

, the expanded coolant liquid is evaporated into low temperature and low pressure coolant gas in the second evaporator

23

, and the low temperature and low pressure coolant gas passes through the second conduit

24

, the third conduit

25

and the first conduit

21

and enters the compressor

16

through the four-way valve

17

and the suction conduit

22

. The air of the heat pump unit chamber

3

cooled by the second evaporator

23

is exhausted out of the housing

1

by means of the exhaustion fan

81

. If the chamber A is ventilated while the air in the heat pump unit chamber

3

is exhausted to the outside as described above, superior drying capacity can be maintained and thermal efficiency can be improved the same as that of the case where the refrigerating and defrosting operations are performed in the chamber A.

When the temperature of the chamber A rises above the set value from the above-described state, the temperature sensor

15

′ renders the temperature sensor relay

56

′ to be ON, thereby closing the sixth solenoid valve

36

through the sixth solenoid valve relay

36

′ by means of the third auxiliary relay

61

and the third auxiliary relay contact

66

, and opening the fourth solenoid valve

34

through the fourth solenoid valve relay

34

′ by the third auxiliary relay contact

66

and simultaneously stopping the second evaporator

23

from being operated by means of the second evaporator relay

23

′. Accordingly, the operation of the first heat exchanger

18

is restored, and so the refrigeration operation in the chamber B is continued.

Meanwhile, when the set time period of the timer

29

′, which is operated as soon as the temperature sensor

15

′ begins to take a temperature, terminates, the timer

29

′ opens the sixth solenoid valve

36

′ through the sixth solenoid valve relay

36

′ using the fourth auxiliary relay

62

and the fourth relay contact

67

through the timer relay

57

′ and the timer relay contact

63

′, closes the fourth solenoid valve

34

through the fourth solenoid valve relay

34

′ by means of the sixth auxiliary relay contact

67

, and allows the second evaporator

23

to be operated by means of the defrosting heater contact

72

′ and simultaneously operates the defrosting heater

18

′ disposed under the first heat exchanger

18

by means of the timer relay contact

63

′ and the defrosting heater relay

58

′ (the operation of first heat exchanger

19

is automatically stopped).

While the first heat exchanger

18

is defrosted by the defrosting heater

18

′ as described above, coolant liquid flowing out of the second condenser

20

is expanded in the third expansion valve

42

and evaporated into low temperature and low pressure coolant gas in the second evaporator

23

, and the evaporated coolant gas passes through the second conduit

24

, the third conduit

25