JP2015039597A - Drying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drying device capable of preventing reduction of the efficiency in drying in an environment where a temperature of outside air is low.SOLUTION: A drying device includes: a heat pump device 70; a drying chamber 32; ducts 61, 63; a temperature sensor 81; a temperature sensor 84; and a control unit 90. The heat pump device 70 comprises a compressor 14 having a drive part 14a and an expansion valve 16. The temperature sensor 81 detects the temperature on the inlet side of an evaporator 17. The temperature sensor 84 detects the temperature of drying air. The control unit 90 controls the heat pump device 70 so that an operation of the drive part 14a is stopped and the degree of opening of the expansion valve 16 is raised when the temperature detected by the temperature sensor 81 is equal to or lower than a first predetermined temperature and the temperature detected by the temperature sensor 84 is equal to or above a second predetermined temperature after starting the operation of the heat pump device 70.

Description

  The present invention relates generally to a drying device, and more particularly to a drying device using a heat pump as a heat source.

  As a conventional drying apparatus using a heat pump as a heat source, for example, a clothes dryer described in Japanese Patent No. 4976965 (hereinafter referred to as Patent Document 1) is known. In the clothes dryer described in Patent Document 1, the drying efficiency is improved by controlling the heat pump according to the target value of the evaporator inlet / outlet temperature difference SH (referred to as superheat degree). Specifically, in the clothes dryer described in Patent Document 1, the drying efficiency is improved by switching the target value of the superheat degree during the drying operation.

  As a control of the heat pump according to the degree of superheat, when the actual degree of superheat is larger than the target value, the heat pump is adjusted so that the actual degree of superheat approaches the target value by increasing the opening of the expansion valve of the heat pump. Control. On the other hand, when the actual degree of superheat is smaller than the target value, the heat pump is controlled so that the actual degree of superheat approaches the target value by lowering the opening of the expansion valve.

  On the other hand, when the actual degree of superheat is zero (zero) or less, a situation occurs in which the refrigerant in the gas-liquid mixed state flows into the compressor of the heat pump. When the compressor compresses the liquid refrigerant, the compressor is damaged.

  In general, it is known that in the process of drying clothing as an object, the amount of water evaporated from the clothing decreases from the middle to the latter half when the amount of water evaporated from the clothing has peaked. Therefore, the control device for the clothes dryer described in Patent Document 1 increases the target value of the evaporator inlet / outlet temperature difference SH (that is, the degree of superheat) from the middle to the latter half when the amount of water evaporation from the clothes has peaked. The operation frequency of the compressor is lowered, and the discharge temperature from the compressor is kept at the same level from the beginning to the middle of the drying operation. In addition, the dehumidifying ability of the evaporator is slightly reduced and the temperature of the evaporator is controlled to be higher. With such control, in the clothes dryer described in Patent Document 1, it is possible to reduce the amount of power consumption by reducing the overall energy used without reducing the drying speed.

Japanese Patent No. 4976965

  Generally, in a drying apparatus using a heat pump as a heat source, a situation occurs in which refrigerant having a temperature lower than 0 ° C. flows through an evaporator in an environment where the temperature of outside air is low, such as in winter. In this case, the evaporator is condensed by the moisture contained in the circulating air, so that heat exchange in the evaporator is hindered. Therefore, the heat exchange amount is reduced in the evaporator. That is, the performance of vaporizing the refrigerant is reduced. Therefore, when controlling the heat pump according to the target value of the superheat degree for the purpose of increasing the heat exchange amount, in order to increase the actual superheat degree, that is, to improve the heat exchange rate in the evaporator, the flow rate of the refrigerant The opening of the expansion valve is lowered so as to limit

  However, when the opening degree of the expansion valve is lowered in accordance with the target value of the superheat degree despite the heat exchange in the evaporator being hindered, the work of the heat pump is reduced, so that the object is dried. It takes a long time to complete or the object cannot be dried. Further, although the heat exchange in the evaporator is hindered, the expansion valve is adjusted according to the superheat target value so that the expansion valve is finally completely closed. An unexpected situation occurs.

  Furthermore, when the expansion valve is completely closed, the flow of the refrigerant is stopped. Therefore, the temperature of the portion (condenser side) between the compressor and the outlet of the expansion valve rises due to the heat of the compressor. . Since this increases the degree of superheat, the expansion valve is once opened. However, after all, the expansion valve is closed again due to the small amount of heat exchange in the evaporator. In this way, when the heat pump is controlled according to the degree of superheat in an environment where the temperature of the outside air is low, the state where the expansion valve is slightly opened and closed is repeated, so that the actual degree of superheat rises and falls Are repeated within a certain temperature range. Specifically, the temperature on the outlet side and the temperature on the inlet side of the evaporator are repeatedly increased and decreased within a certain temperature range. In such a situation, the ability to dry the object is not exhibited in the heat pump and the drying device.

  For such a situation, even in an environment where the temperature of the outside air is low, by controlling the heat pump according to the target value of the degree of superheat, it is possible to suppress an increase in the time required for drying an object such as clothing. Therefore, a drying apparatus that can prevent a decrease in drying efficiency is desired.

  Therefore, an object of the present invention is to provide a drying apparatus capable of preventing a decrease in drying efficiency in an environment where the temperature of the outside air is low.

  A drying device according to one aspect of the present invention includes a heat pump device, a drying chamber, an air circulation path, a temperature detector, and a control unit. The heat pump device includes a compressor having a drive unit and an expansion valve that adjusts the pressure of the refrigerant. The air circulation path is configured so that the air heated by the heat pump device is supplied to the drying chamber, and the air whose humidity is increased in the drying chamber is returned to the heat pump device. It is arranged between. The temperature detector detects at least one temperature selected from the group consisting of a temperature at a predetermined location of the heat pump device and a temperature of air flowing through the duct. The control unit controls the heat pump device.

  The temperature detector includes a first detector and a second detector that detects a temperature at a position different from the temperature at the position detected by the first detector. The controller, after operating the heat pump device, the temperature detected by the first detector is equal to or lower than the first predetermined temperature, and the temperature detected by the second detector is the second predetermined temperature. When the temperature is equal to or higher than the temperature, the heat pump device is controlled to stop the operation of the drive unit and to increase the opening of the expansion valve.

  A drying device according to another aspect of the present invention includes a heat pump device, a fourth detector, a fifth detector, and a control unit. The heat pump device includes a compressor having a drive unit, an expansion valve that adjusts the pressure of the refrigerant, and an evaporator that vaporizes the refrigerant. The fourth detector detects the temperature on the inlet side of the refrigerant in the evaporator. The fifth detector detects the temperature on the outlet side of the refrigerant in the evaporator. The control unit controls the heat pump device.

  In the drying apparatus according to another aspect of the present invention, the control unit, after operating the heat pump device, sets the temperature detected by the fourth detector and the temperature detected by the fifth detector. Calculate the difference. The control unit controls the heat pump device to adjust the opening of the expansion valve so that the calculated temperature difference value approaches a preset target value. Furthermore, the control unit controls the heat pump device so as to stop the operation of the drive unit and increase the opening of the expansion valve when the temperature difference repeatedly increases and decreases within a predetermined temperature range. To do.

  ADVANTAGE OF THE INVENTION According to this invention, the drying apparatus which can prevent that drying efficiency falls in the environment where the temperature of external air is low can be provided.

It is the schematic which shows the structure of an example of the drying apparatus according to this invention. It is the schematic which shows the heat pump apparatus controlled by the control part of an example of the drying apparatus according to this invention. It is a block diagram which shows each structure controlled by the control part of an example of the drying apparatus according to this invention. When an example of a drying apparatus according to the present invention operates in an environment where the temperature of the outside air is low, the control unit controls the drive unit to stop the operation of the drive unit and increases the opening of the expansion valve. Fig. 6 is a graph showing changes per unit time in actual superheat degree before and after the control unit controls the expansion valve. When an example of a drying apparatus according to the present invention operates in an environment where the temperature of the outside air is low, the control unit controls the drive unit to stop the operation of the drive unit and increases the opening of the expansion valve. 6 is a graph showing changes per unit time in temperature at each position of the heat pump device before and after the control unit controls the expansion valve.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a drying apparatus 100 as an example of a drying apparatus according to the present invention. The drying device 100 is a laundry dryer having functions such as washing and rinsing in addition to a drying function. As shown in FIG. 1, the drying apparatus 100 includes an outer box 1. The outer box 1 forms the outer shape of the main body of the drying device 100. A panel (not shown) including an operation unit for selecting a washing condition and a drying condition is attached to the outer box 1.

  The drying device 100 includes a heat pump device 70, a control unit 90, a blower 9, a water tub 2, a washing tub 3, and a drive mechanism 4. The washing tub 3 rotates based on the operation of the drive mechanism 4.

  The washing tub 3 has a cylindrical shape. In the cylinder, one end side (left side in FIG. 1) is opened, and the other end side (right side in FIG. 1) forms a bottom portion 3b having a bottom wall. The washing tub 3 rotates around a rotation axis extending in a direction inclined from the horizontal direction or in the horizontal direction. A stainless steel plate is generally used as a material for the washing tub 3. A plurality of small holes (not shown) for water supply, drainage and ventilation are formed in the peripheral wall 3a and the bottom 3b of the washing tub 3. The peripheral wall 3 a is a cylindrical part of the washing tub 3. The peripheral wall 3a has a substantially cylindrical shape. The peripheral wall 3a extends in a direction substantially parallel to the direction in which the rotation axis extends.

  A plurality of baffles (not shown) are arranged on the peripheral wall 3a. The baffle extends in a direction substantially parallel to the direction in which the rotation axis extends. Further, the baffle protrudes from the peripheral wall 3a inward in the radial direction of a circle centered on the rotation axis.

  The water tank 2 has a cylindrical shape. In the cylinder, one end side is open and the other end side has a bottom wall. The washing tub 3 is accommodated in the space inside the water tub 2. A counterweight (not shown) is attached to the lower part of the water tank 2. A plurality of counterweights may be attached to the water tank 2 in order to balance the entire water tank 2. The counterweight may be attached to the upper part of the water tank 2. A liquid balancer (not shown) is attached outside the edge of the opening of the washing tub 3.

  The washing tub 3 stores the laundry 5 as an object to be dried. A drive shaft 41 is fixed to the bottom 3 b of the washing tub 3. The drive mechanism 4 including the drive shaft 41 is attached to the bottom 2 b of the water tank 2. The drive shaft 41 is connected to the drive mechanism 4.

  The drying device 100 uses the heat pump device 70 as a heat source. As shown in FIG. 2, the heat pump device 70 includes a compressor 14, a condenser 15, an evaporator 17, and an expansion valve 16. The compressor 14 compresses the refrigerant and raises the temperature of the refrigerant. The condenser 15 heats the air by exchanging heat between the refrigerant compressed by the compressor 14 and the air. The expansion valve 16 reduces the pressure of the refrigerant that heated the air. That is, the expansion valve 16 adjusts the refrigerant pressure. The evaporator 17 cools the air by exchanging heat between the decompressed refrigerant and the air. As a result, the refrigerant is vaporized in the evaporator 17. In addition, the heat pump device 70 includes a refrigerant pipe 18. The refrigerant pipe 18 is connected to the compressor 14, the condenser 15, the expansion valve 16, the evaporator 17, and the compressor 14, so that the refrigerant circulates in this order. And

  The condenser 15 and the evaporator 17 are fin tube type heat exchangers, respectively. In the heat pump device 70, drying air flows through the evaporator 17 and the condenser 15 in the order of the evaporator 17 and the condenser 15.

  The compressor 14 has a drive unit 14 a that drives the compressor 14. The drive unit 14 a constitutes a drive source for the compressor 14. A preferred example of the drive unit 14a is an induction motor. The motor as the drive unit 14a may be another electric motor.

  The blower 9 has a rotating part 9a. The rotating part 9a has a configuration including a general electric motor. The driving unit 14a of the compressor 14 and the rotating unit 9a of the blower 9 are each connected to a circuit 89 including a switch (not shown). The control unit 90 controls the switch so that the switch included in the circuit 89 is switched on and off, whereby the rotation start and rotation stop of the drive unit 14a and the rotation start and rotation stop of the rotation unit 9a are performed. Can be switched.

  As shown in FIG. 1, the drying apparatus 100 includes a drying chamber 32 and a duct 60. The space inside the washing tub 3 functions as the drying chamber 32. The drying chamber 32 is supplied with air heated in the condenser 15 (see FIG. 2) of the heat pump device 70. The blower 9 sends the heated air to the drying chamber 32. The duct 60 is connected to the drying chamber 32 and the heat pump so that the air heated by the heat pump device 70 is supplied to the drying chamber 32 and the air whose humidity is increased in the drying chamber 32 is returned to the heat pump device 70. Connected to the device 70. The duct 60 is an example of a path for circulating air, and is configured by connecting pipe members.

  The duct 60 includes an exhaust duct 61, a connection portion 62, and an air supply duct 63. The duct 63 is disposed between the condenser 15 and the drying chamber 32 so that the air heated in the condenser 15 is supplied to the drying chamber 32. The duct 61 is disposed between the drying chamber 32 and the evaporator 17 so that air used for drying the laundry 5 in the drying chamber 32 flows toward the evaporator 17. The connecting portion 62 is a portion of the duct 60 that extends between the condenser 15 and the blower 9. In the drying process as the process of drying the laundry 5, the air used for drying the laundry 5 (this is called drying air) flows through the duct 60 along the direction indicated by the two-dot chain line arrow. Circulates between the drying chamber 32 and the heat pump device 70.

  FIG. 3 is a block diagram showing each configuration controlled by the control unit 90 of the drying apparatus 100. As shown in FIG. 3, the control unit 90 includes a detection unit 91, a calculation unit 92, a heating control unit 97, and a blower control unit 96. The detection unit 91 includes a temperature detection unit 911. The heating control unit 97 includes a compressor control unit 971 and a flow rate control unit 972. Further, the control unit 90 includes a determination unit 93, a storage unit 94, and a timer 95.

  The calculation for the control necessary for the operation of the drying apparatus 100 is performed by the calculation unit 92. The determination about the control necessary for the operation of the drying apparatus 100 is performed by the determination unit 93. The storage unit 94 stores data and the like necessary for the operation of the drying apparatus 100.

  The storage unit 94 includes a ROM (Read Only Memory) and a RAM (Random Access Memory). In addition, the process of the drying apparatus 100 (see FIG. 1) includes a washing process, a rinsing process, and a dehydrating process in order as a process before the drying process. Information on the operation of each member in each stroke is recorded in the storage unit 94 after being programmed, for example. However, the information on the operation of each member in each stroke may be recorded in the storage unit 94 simply in a map shape or a table shape.

  The control unit 90 controls each member of the drying device 100 including the heat pump device 70 and the rotating unit 9a of the blower 9 in accordance with information recorded in a program or the like. The blower control unit 96 controls the rotating unit 9 a of the blower 9. The compressor control unit 971 controls the drive unit 14 a of the compressor 14. The flow rate control unit 972 controls the expansion valve 16 to adjust the flow rate of the refrigerant flowing through the refrigerant pipe 18 (see FIG. 2).

  When the flow rate control unit 972 controls the expansion valve 16 so as to reduce the opening degree of the expansion valve 16, the resistance in the refrigerant pipe 18 (see FIG. 2) increases and the degree of superheat increases. When the flow rate control unit 972 controls the expansion valve 16 so as to increase the opening degree of the expansion valve 16, the resistance in the refrigerant pipe 18 (see FIG. 2) decreases, and the degree of superheat decreases.

  Also, the operation of the drive mechanism 4 (see FIG. 1) of the washing tub 3 and the operation of a water supply valve (not shown) that opens and closes the flow path through which the water supplied to the water tub 2 (see FIG. 1) passes, etc. The operation of each member in the drying apparatus 100 is based on the control of the control unit 90.

  As shown in FIG. 2, a temperature sensor 81 is disposed in the vicinity of the inlet of the evaporator 17 in the heat pump device 70. The temperature sensor 81 detects the temperature on the inlet side of the evaporator 17. In the heat pump device 70, a temperature sensor 82 is disposed in the vicinity of the outlet of the evaporator 17. The temperature sensor 82 detects the temperature on the outlet side of the evaporator 17.

  A temperature sensor 83 is disposed at the discharge portion of the compressor 14. The temperature sensor 83 detects the temperature of the discharge part of the compressor 14. Alternatively, the temperature sensor 83 can detect the temperature of the refrigerant. In addition, the discharge part of the compressor 14 is a part of the compressor 14 and is a part located on the side where the refrigerant flows out of the compressor 14 rather than the part on the side where the refrigerant flows into the compressor 14. is there. Alternatively, the discharge part of the compressor 14 may be a part of the refrigerant pipe 18 through which the refrigerant flowing out of the compressor 14 passes, and may be a connection part between the refrigerant pipe 18 and the compressor 14.

  A temperature sensor 84 is disposed in the duct 61. The temperature sensor 84 detects the temperature of the air flowing through the duct 61. Alternatively, the temperature sensor 84 can detect the temperature of the duct 61. The temperature sensor 84 is arranged in the duct 61 closer to the heat pump device 70 than the drying chamber 32. In addition, the position of the temperature sensor 84 in the duct 61 is not particularly limited, and may be disposed closer to the drying chamber 32 than the heat pump device 70, and is at a substantially intermediate position between the heat pump device 70 and the drying chamber 32. It may be arranged. A temperature sensor 85 is disposed in the condenser 15. The temperature sensor 85 detects the temperature of the intermediate part of the condenser 15.

  The temperature sensor 86 detects the temperature outside the drying apparatus 100 (see FIG. 1). The place where the temperature sensor 86 is disposed is not particularly limited, and may be the outer surface of the outer box 1 (see FIG. 1), and the inner side of the outer box 1 so as to be accommodated in the outer box 1. Also good.

  The temperature sensor 81 is an example of a first detector. The temperature sensor 84 is an example of a second detector. The temperature sensor 82 is an example of a third detector.

  The temperature detection unit 911 (see FIG. 3) of the detection unit 91 is electronically or electrically connected to the temperature sensors 81, 82, 83, 84, 85, 86. The temperature detection unit 911 includes a temperature on the inlet side of the evaporator 17 (see FIG. 2) detected by the temperature sensor 81, a temperature on the outlet side of the evaporator 17 detected by the temperature sensor 82, and a compression detected by the temperature sensor 83. Of the discharge section of the machine 14 (see FIG. 2), the temperature of the air flowing through the duct 61 (see FIG. 2) detected by the temperature sensor 84, and the condenser 15 (see FIG. 2) detected by the temperature sensor 85. The temperature of the intermediate portion and the temperature outside the drying device 100 (see FIG. 1) detected by the temperature sensor 86 (that is, the temperature of the outside air) are detected.

  The calculation unit 92 is configured so that the temperature on the inlet side of the evaporator 17 (see FIG. 2) detected by the temperature sensor 81 and the temperature detection unit 911, and the evaporator 17 (detected by the temperature sensor 82 and the temperature detection unit 911). The difference from the temperature on the outlet side in FIG. 2) is calculated. The flow rate control unit 972 controls the expansion valve 16 so that the value of the temperature difference (that is, the degree of superheat) calculated by the calculation unit 92 approaches the target value.

  Below, operation | movement of each member which heats the air supplied to the drying chamber 32 in order to dry the laundry 5 among the drying processes of the drying apparatus 100 is demonstrated using FIGS. 1-3.

  When the drying process program is launched, the controller 90 rotates the washing tub 3 by driving the drive mechanism 4. In order to heat the air supplied to the drying chamber 32, the control unit 90 drives the driving unit 14 a of the compressor 14 to increase the pressure of the refrigerant and increase the temperature. The control unit 90 rotates the rotating unit 9 a of the blower 9 so that air heated by exchanging heat with the refrigerant is supplied to the drying chamber 32. Air for drying the laundry 5 flows through the duct 60 as indicated by the two-dot chain line arrow shown in FIG. 1 by the air flow generated by the blower 9. 2 and 2 schematically indicate the direction in which the airflow flows, and do not indicate the velocity or scale of the airflow.

  The air flowing into the drying chamber 32 by the air flow generated by the blower 9 obtains moisture from the laundry 5 stirred in the drying chamber 32 and circulates through the duct 61 toward the heat pump device 70. The air in the duct 61 includes moisture that evaporates from the laundry 5. The air flowing into the heat pump device 70 from the duct 61 is dehumidified below the dew point when passing through the evaporator 17. The dehumidified air is heated in the condenser 15 to be heated and reduced in humidity, and flows again into the washing tub 3 as drying air. By repeating such an air flow, the laundry 5 is dried.

  In the drying device 100, the heat pump device 70 is controlled so that the actual degree of superheat approaches a preset target value. By controlling the expansion valve 16 so that the degree of superheat converges in the vicinity of the target value, it is possible to suppress a decrease in the heat exchange performance of the heat pump device 70, and thus it is possible to improve the drying efficiency.

  Information on the target value of the degree of superheat is stored in the storage unit 94 in advance. The flow rate control unit 972 controls the expansion valve 16 based on the target value information stored in the storage unit 94 (see FIG. 3 for both). The flow rate control unit 972 has a superheat degree calculated by the calculation unit 92 (in other words, the difference between the temperature near the inlet of the evaporator 17 (see FIG. 2) and the temperature of the outlet of the evaporator 17) as a target value. The expansion valve 16 is controlled so as to approach.

  As will be described below, the controller 90 detects that the temperature detected by the temperature sensor 81 is equal to or lower than the first predetermined temperature and the temperature detected by the temperature sensor 84 after the heat pump device 70 is operated. When the temperature is equal to or higher than the second predetermined temperature, the heat pump device 70 is controlled so as to stop the operation of the drive unit 14a and increase the opening degree of the expansion valve 16 (see FIG. 2 for both).

  FIG. 4 shows that when the drying apparatus 100 is operated in an environment where the temperature of the outside air is low, the control unit 90 (see FIG. 2) controls the drive unit 14a so as to stop the operation of the drive unit 14a (see FIG. 2). And it is a graph which shows the change per unit time of the actual superheat degree before and after the control part 90 controls the expansion valve 16 so that the opening degree of the expansion valve 16 (refer FIG. 2) may be raised.

  The F line shown in FIG. 4 is a line which shows the rotation speed of the rotation part 9a (refer FIG. 2) of the air blower 9. As shown in FIG. The operation of the blower 9 is started with the start of the drying process. The rotational speed of the rotating part 9a of the blower 9 rises to a predetermined rotational speed set in two stages after the start of operation. The operation of the blower 9 continues at the predetermined rotation number (for example, 4600 rpm) until the end of the drying operation. The line E shown in FIG. 4 is a line indicating the rotational speed of the drive unit 14a (see FIG. 2) of the compressor 14. With the start of the drying process, the operation of the compressor 14 is started. The rotation speed of the drive unit 14a of the compressor 14 rises to a predetermined rotation speed (5000 rpm as an example) after the start of operation. While the compressor 14 is operating at this predetermined rotational speed, the operation of the compressor 14 is temporarily stopped to prevent condensation or defrost in the evaporator 17 as described later. Thereafter, after a while, the operation of the compressor 14 is resumed. The rotational speed of the drive unit 14a at this time is the same as the rotational speed before stopping.

  The line D shown in FIG. 4 is a line indicating the target value of the superheat degree. Moreover, the C line shown in FIG. 4 is a line which shows the calculated actual superheat degree. In the heat pump device 70 (see FIG. 1) of the drying device 100, the expansion valve 16 (see FIG. 2) is controlled so that the actual degree of superheat converges to the target value. A line indicating the opening degree of the expansion valve 16 is a line A in FIG. Moreover, the integral opening degree of the expansion valve 16 is shown by the B line of FIG. After the drying process is started, the opening degree of the expansion valve 16 is once throttled from the fully opened state, and then adjusted according to the superheat degree target value. As will be described later, the opening degree of the expansion valve 16 is fully opened when the operation of the compressor 14 is temporarily stopped in order to prevent condensation or defrost in the evaporator 17. Thereafter, after a while, when the operation of the compressor 14 is resumed, the opening degree of the expansion valve 16 is once reduced by a predetermined amount. The opening degree of the expansion valve 16 is once throttled and then adjusted in accordance with the target value of the superheat degree. The line B in FIG. 4 changes as the line A changes.

  As shown in FIG. 4, at the operation start time ST for drying the laundry 5, the operation of the compressor 14 (see FIG. 2) is started and the rotation of the blower 9 (see FIG. 2) is started. (Refer to E line and F line in FIG. 4). The rotational speed of the blower 9 once rises to an intermediate level and then rises to a predetermined rotational speed that has been set. Moreover, after the opening degree of the expansion valve 16 is once reduced by a predetermined amount from the fully opened state, it is adjusted in accordance with the target value of the degree of superheat (see line A in FIG. 4).

  Note that the time when the drying process is started or the time when the drying operation is started means the time when the drying process program is started. However, it may be the time when the compressor 14 is activated, or may be the time when the rotation of the drive unit 14a is started. In addition, the part extended in the direction parallel to at least the horizontal axis of the E line and the F line shown in FIG. 4 and the D line represent not a measured value or a detected value but a quantitative value for control. A portion extending in a direction parallel to the vertical axis of the E line and the F line shown in FIG. 4 simply indicates an ascending or descending state.

  FIG. 5 shows that the controller 90 (see FIG. 2) controls the drive unit 14a to stop the operation of the drive unit 14a (see FIG. 2) when the drying apparatus 100 operates in an environment where the temperature of the outside air is low. And the graph which shows the change per unit time of the temperature of each position of the heat pump apparatus 70 before and after the control part 90 controls the expansion valve 16 so that the opening degree of the expansion valve 16 (refer FIG. 2) may be raised. It is. As each position in the heat pump apparatus 70, the temperature of the discharge part of the compressor 14 (refer FIG. 2), the temperature of the intermediate part of the condenser 15 (refer FIG. 2), the temperature of the air which distribute | circulates the duct 61 (refer FIG. 2), Changes in the temperature on the outlet side of the evaporator 17 (see FIG. 2) and the temperature on the inlet side of the evaporator 17 are shown in FIG. That is, FIG. 5 shows changes per unit time in temperature detected by the temperature sensors 81 to 85 and the temperature detection unit 911 (see FIG. 3).

  After the drying process is started, the heat pump device 70 is in a state where the side of the condenser 15 (see FIG. 2) in the heat pump device 70 is higher than the temperature of the evaporator 17 side. Therefore, as shown in FIG. 5, the temperature of the intermediate part of the condenser 15 (see the H line in FIG. 5) rises, and the temperature of the discharge part of the compressor 14 (see the G line in FIG. 5) rises. . Further, the temperature of the drying air that absorbs heat from the condenser 15 rises. This drying air is detected as the temperature of the exhaust gas after passing through the drying chamber 32 (see FIG. 1) (see the I line in FIG. 5).

  When the drying device 100 is installed in an environment where the temperature of the outside air is relatively low, a situation occurs in which the evaporator 17 is condensed by moisture contained in the drying air. As a result, as shown in FIG. 5, the temperature on the inlet side (see the K line in FIG. 5) is higher than the temperature on the outlet side of the evaporator 17 (see the J line in FIG. 5). In this case, the performance of vaporizing the refrigerant in the evaporator 17 decreases. Therefore, in order to increase the actual superheat degree (that is, the calculated superheat degree), the opening degree of the expansion valve 16 is lowered by controlling the heat pump device 70 according to the target value of the superheat degree (FIG. 4 line A).

  However, although the opening degree of the expansion valve 16 is adjusted in accordance with the target value of the superheat degree despite the heat exchange in the evaporator 17 being hindered, the expansion valve 16 is finally completely removed. A situation occurs in which the door is closed (see lines A and B in FIG. 4). When the expansion valve 16 is completely closed, the flow of the refrigerant is stopped. Therefore, a portion of the heat pump device 70 between the compressor 14 and the outlet of the expansion valve 16 (condenser 15) is heated by the heat of the compressor 14. (See the G and H lines in FIG. 5). As a result, the degree of superheat rises, so that the expansion valve 16 is once opened.

  However, the expansion valve 16 is closed again due to the small amount of heat exchange in the evaporator 17. Thus, when the heat pump device 70 is controlled according to the degree of superheat in an environment where the temperature of the outside air is low, the expansion valve 16 is slightly opened and closed repeatedly, so that the actual superheat degree The rise and fall are repeated within a certain temperature range (see line C in FIG. 4). Specifically, the temperature on the outlet side of the evaporator 17 (see line J in FIG. 5) and the temperature on the inlet side (see line K in FIG. 5) rise in a certain temperature range including temperatures below zero. And descent are repeated (refer to the area surrounded by the dashed ellipse shown in FIG. 5). Further, by repeatedly opening and closing the expansion valve 16, the temperature of the discharge portion of the compressor 14 (see the G line in FIG. 5) and the temperature of the intermediate portion of the condenser 15 (see the H line in FIG. 5) are also obtained. , The ascending and descending are repeated respectively.

  Therefore, the control unit 90 (see FIG. 3) determines that the temperature on the inlet side of the evaporator 17 detected by the temperature sensor 81 is, for example, 0 ° C. or less, and the temperature of the exhaust detected by the temperature sensor 84 is, for example, When it is detected by the temperature detection part 911 that it is 15 degreeC or more, the heat pump apparatus 70 is controlled so that the action | operation of the drive part 14a may be stopped and the opening degree of the expansion valve 16 may be raised. During this time, the operation of the blower 9 is continued. As described above, in the drying apparatus 100, it is possible to appropriately estimate an abnormal state (or an unfavorable state) from the viewpoint of heat exchange of the heat pump device 70 such as a state where frost is generated in the evaporator 17 at an early stage. It is possible to quickly return to the state (or a preferable state).

  As shown in FIG. 4, when the operation of the compressor 14 is temporarily stopped, the expansion valve 16 is fully opened. Furthermore, after a lapse of, for example, 5 minutes from when the operation of the compressor 14 is temporarily stopped, the operation of the compressor 14 is resumed, and the expansion valve 16 is once throttled from the fully opened state. Is adjusted to the target value of the superheat degree. When the operation of the compressor 14 is temporarily stopped, the amount of heat is exchanged between the relatively warm refrigerant staying on the condenser 15 side and the relatively cool refrigerant staying on the evaporator 17 side. As a result, the refrigerant in the entire heat pump device 70 shifts to an equilibrium state. Therefore, frost generation can be prevented or defrosted by increasing the temperature of the surface of the evaporator 17 as the temperature of the refrigerant on the evaporator 17 side increases.

  More preferably, the temperature on the inlet side of the evaporator 17 detected by the temperature sensor 81 is equal to or lower than 0 ° C. after the start of the drying process, that is, when a predetermined time has elapsed after the heat pump device 70 is operated. In that case, the control unit 90 controls the heat pump device 70 so that the drive unit 14a operates at a higher rotational speed than a preset rotational speed. In addition, the example of the predetermined time after the operation | movement of the heat pump apparatus 70 is 20 minutes, for example. The predetermined rotation speed of the drive unit 14a of the compressor 14 set in advance is, for example, 3000 rpm. It is preferable to rotate the drive unit 14a at 5000 rpm as described above, for example, as a value increased by about 66% with respect to the number of rotations. In this way, the condensation capacity can be improved by increasing the output of the compressor 14. Thereby, since the temperature of the drying air can be raised at an early stage, condensation of the evaporator 17 can be prevented or defrosted.

  Further, as shown in FIG. 4, when the operation of the compressor 14 is resumed (see the E line in FIG. 4), the compressor 14 is used until the operation of the compressor 14 is temporarily stopped after the drying process is started. Instead of the target value of the degree of superheat, a target value of a higher value is used (see line D in FIG. 4). In other words, until the operation of the compressor 14 is temporarily stopped after the start of the drying process, the actual superheat degree is set to an alternative value that is a target value smaller than the target value set in advance for the drying operation. The expansion valve 16 is controlled to approach. That is, in the drying apparatus 100, when the temperature detected by the temperature sensor 81 is 0 ° C. or less as an example of the first predetermined temperature, the actual value is set to an alternative value set to a value smaller than the target value. The expansion valve 16 is controlled so that the degree of superheating approaches. Specifically, when the temperature detected by the temperature sensor 81 is equal to or lower than 0 ° C., the flow rate control unit 972 (see FIG. 3) sets an alternative value set to a value smaller than a preset target value. The expansion valve 16 is controlled so that the degree of superheat approaches.

  More preferably, after resuming the operation of the compressor 14 (see the E line in FIG. 4), the control unit 90 follows the target value that increases stepwise as indicated by the D line in FIG. The heat pump device 70 is controlled. The target value used here is set stepwise according to the detected temperature of the evaporator 17. As an example, when the temperature on the inlet side of the evaporator 17 is 0.5 ° C. or less, the target value is set to 0.5 ° C. For example, when the temperature on the inlet side of the evaporator 17 is 2.5 ° C. or higher, the target value is set to 4,5 ° C. When the temperature on the inlet side of the evaporator 17 is higher than 0.5 ° C and lower than 2.5 ° C, the target value is obtained by linear interpolation in the range of 0.5 ° C or higher and 4.5 ° C or lower. Get the function value. By using these target values that change stepwise, the expansion valve 16 will not close excessively around the temperature range where condensation is estimated, and recovery is estimated from the occurrence of frost. The heat pump device 70 can be controlled so that the expansion valve 16 does not open excessively to cause frost again.

  In this way, it is possible to improve the condensation capability by increasing the output of the compressor 14 and further increase the flow rate of the refrigerant by using a lower superheat degree target value. Thereby, the temperature of drying air can be raised early from the time of the drying process being started. In addition, after the temperature of the drying air is raised early, the control unit 90 stops the operation of the compressor 14 and increases the opening degree of the expansion valve 16. Thereby, since the refrigerant in the entire heat pump device 70 shifts to an equilibrium state, defrosting can be performed by increasing the temperature of the surface of the evaporator 17 as the temperature of the refrigerant on the evaporator 17 side increases.

  Thus, in the drying apparatus 100, the abnormal state in terms of the heat exchange rate of the heat pump device 70 can be estimated at an early stage, whereby the proper state can be quickly restored. Therefore, since heat pump device 70 and drying device 100 can be operated in an appropriate state, it is possible to prevent a decrease in drying efficiency.

  As described above, the drying device 100 according to the first embodiment includes the heat pump device 70, the drying chamber 32, the duct 60, the temperature sensor 81, the temperature sensor 84, and the control unit 90. The heat pump device 70 includes a compressor 14 having a drive unit 14a and an expansion valve 16 that adjusts the pressure of the refrigerant. The duct 60 constituting the air circulation path is supplied to the drying chamber 32 with the air heated by the heat pump device 70, and the air whose humidity is increased in the drying chamber 32 is returned to the heat pump device 70. In this way, the drying chamber 32 and the heat pump device 70 are connected. The temperature sensor 81 detects the temperature on the inlet side of the evaporator 17 of the heat pump device 70. The temperature sensor 84 detects the temperature of the air flowing through the duct 60. The control unit 90 controls the heat pump device 70.

  After the heat pump device 70 is operated, the controller 90 detects a temperature detected by the temperature sensor 81 equal to or lower than a first predetermined temperature, and a temperature detected by the temperature sensor 84 equals or exceeds a second predetermined temperature. If this is the case, the heat pump device 70 is controlled so as to stop the operation of the drive unit 14a and to increase the opening of the expansion valve 16.

  According to this configuration, in the drying apparatus 100, an appropriate state can be obtained by presuming an abnormal state (or an unfavorable state) from the viewpoint of heat exchange of the heat pump device 70, such as a state where the evaporator 17 is condensed. (Or a preferable state) can be restored early.

  That is, when the expansion valve 16 is opened when the operation of the compressor 14 is temporarily stopped, a relatively warm refrigerant staying on the condenser 15 side and a relatively cold refrigerant staying on the evaporator 17 side. The amount of heat is exchanged between the refrigerant and the refrigerant in the entire heat pump device 70 shifts to an equilibrium state. Therefore, the temperature on the surface of the evaporator 17 also rises as the temperature of the refrigerant on the evaporator 17 side rises, so that condensation of the evaporator 17 can be prevented or defrosted.

  By doing in this way, the drying apparatus 100 which can prevent that drying efficiency falls in the environment where the temperature of external air is low can be provided.

  In the drying device 100, when a predetermined time has elapsed after the heat pump device 70 is operated, if the temperature detected by the temperature sensor 81 is equal to or lower than 0 ° C., the rotation speed is higher than a preset rotation speed. The control unit 90 controls the heat pump device 70 so that the drive unit 14a is activated by the number.

  According to this structure, the capability of condensation can be improved by raising the output of the compressor 14. Thereby, since the temperature of the drying air can be raised at an early stage, condensation of the evaporator 17 can be prevented or defrosted.

  The heat pump device 70 includes an evaporator 17 that vaporizes the refrigerant. Moreover, the drying apparatus 100 includes a temperature sensor 82 that detects the temperature of the outlet side of the refrigerant in the evaporator 17 as a temperature detector. In the drying apparatus 100, the temperature sensor 81 detects the temperature on the inlet side of the refrigerant in the evaporator 17. The control unit 90 calculates the difference (that is, the degree of superheat) between the temperature detected by the temperature sensor 81 and the temperature detected by the temperature sensor 82, and the calculated superheat degree approaches the preset target value. When the temperature detected by the temperature sensor 81 is equal to or lower than 0 ° C., the superheat value approaches the substitute value set to a value smaller than the target value. The expansion valve 16 is controlled.

  According to this configuration, the flow rate of the refrigerant can be increased by using a lower superheat degree target value. Thereby, since the temperature of drying air can be raised at an early stage from the time when the drying process is started, frost growth in the evaporator 17 can be suppressed after the start of the drying operation. Further, after the temperature of the drying air is raised early, the operation of the compressor 14 is stopped and the opening degree of the expansion valve 16 is increased. Thereby, since the refrigerant in the entire heat pump device 70 shifts to an equilibrium state, defrosting can be performed by increasing the temperature of the surface of the evaporator 17 as the temperature of the refrigerant on the evaporator 17 side increases.

  In the drying device 100, the heat pump device 70 includes an evaporator 17 that vaporizes the refrigerant. The temperature sensor 81 detects the temperature of the refrigerant inlet side in the evaporator 17. The temperature sensor 84 detects the temperature of air in the duct 61 that forms a path from the drying chamber 32 to the evaporator 17 in the duct 60.

  According to this configuration, the temperature on the inlet side that is higher than the temperature on the outlet side of the evaporator 17 is detected, and the temperature of the exhaust gas containing water vapor is detected, so that condensation of the evaporator 17 can be easily performed. It can be estimated appropriately.

  Note that examples of the first predetermined temperature and the second predetermined temperature are not limited to the above examples. For example, an example of the first predetermined temperature is a temperature at which the evaporator 17 can be estimated to condense, and may be around 1 ° C. On the other hand, as an example of the second predetermined temperature, by using a lower temperature as a threshold value in the exhaust gas temperature range of 10 ° C. or more and 20 ° C. or less, the occurrence of condensation in the evaporator 17 is reduced after the start of the drying process. It may be estimated at an earlier time.

  In the drying apparatus 100, the temperature on the inlet side of the evaporator 17 detected by the temperature sensor 81 is the first temperature after the start of the drying process, that is, when a predetermined time has elapsed after the heat pump apparatus 70 is operated. When the temperature is equal to or lower than 0 ° C. as an example of the predetermined temperature, the heat pump device 70 is controlled such that the drive unit 14a operates at a rotational speed higher than a preset rotational speed. As another example of control, in the drying apparatus 100, when the temperature of the exhaust gas detected by the temperature sensor 83 is the third predetermined temperature when a predetermined time has elapsed after the heat pump device 70 is operated. The heat pump device 70 may be controlled such that the drive unit 14a operates at a higher rotational speed than a preset rotational speed. Here, an example of the third predetermined temperature is, for example, 10 ° C., and an example of the predetermined time after the operation of the heat pump device 70 is, for example, 5 minutes. As described above, in the drying apparatus 100, the output of the compressor 14 may be increased early based on the degree of increase in the exhaust gas temperature after the start of operation.

  In the drying apparatus 100, the temperature sensors 81, 82, 83, 85 detect the temperature at a predetermined location of the heat pump device 70. Specifically, the temperature sensor 81 detects the temperature on the inlet side of the evaporator 17. The temperature sensor 82 detects the temperature on the outlet side of the evaporator 17. The temperature sensor 83 detects the temperature of the discharge part of the compressor 14. The temperature sensor 85 detects the temperature of the intermediate part of the condenser 15. Further, the drying apparatus 100 includes a temperature sensor 84 that detects the temperature of the exhaust gas flowing through the duct 61. Among these sensors, in the drying apparatus 100, an example of the second detector is a temperature sensor 84. However, the example of the second detector may be a temperature sensor 82 that detects the temperature on the outlet side of the evaporator 17, or may be a temperature sensor 85 that detects the temperature of the intermediate portion of the condenser 15. A temperature sensor 83 that detects the temperature of the discharge part of the compressor 14 may be used.

  On the other hand, an example of the first detector is a temperature sensor 81. However, the example of the first detector may be the temperature sensor 82 that detects the temperature on the outlet side of the evaporator 17, or the temperature sensor 85 that detects the temperature of the intermediate portion of the condenser 15. Moreover, the temperature sensor 83 that detects the temperature of the discharge part of the compressor 14 or the temperature sensor 84 that detects the temperature of the exhaust gas flowing through the duct 61 may be used. As described above, as the predetermined threshold value for control, two temperatures selected from the group consisting of the temperature of the predetermined location in the heat pump device 70 and the temperature of the air flowing through the duct 61 are appropriately set based on experiments and the like. By setting to, the condensation of the evaporator 17 can be estimated appropriately at an early stage.

  Alternatively, the drying apparatus 100 stops the operation of the drive unit 14a based on the temperature detected by the temperature sensor 86 so that the temperature of the outside air detected by the temperature sensor 86 is used as it is for estimation. The heat pump device 70 may be controlled to increase the opening degree of the expansion valve 16.

  The expansion valve 16 is an example of a throttle part for adjusting the flow rate of the refrigerant. In addition, as a structure which adjusts the flow volume of a refrigerant | coolant, you may be comprised with the capillary tube.

  In addition, the position where the control part 90 is arrange | positioned in the drying apparatus 100 is not specifically limited. The control unit 90 shown in FIG. 1 is shown schematically and may be any unit that exhibits a desired function as described above.

  Note that the environment where the temperature of the outside air is low refers to an environment where the outside air is approximately 5 ° C. or less and the evaporator 17 is condensed.

  The drying device according to the present invention may not have functions such as washing and rinsing. The drying apparatus according to the present invention may be a drying apparatus having a drying function.

(Second Embodiment)
Below, the drying apparatus of 2nd Embodiment is demonstrated. In addition, below, the same code | symbol is attached | subjected to the structure which has the function similar to the structure of the drying apparatus 100 of 1st Embodiment.

  The difference between the drying device of the second embodiment and the drying device 100 of the first embodiment is that, in the drying device of the second embodiment, the actual degree of superheat repeatedly rises and falls within a predetermined temperature range. The heat pump device 70 is controlled so as to stop the operation of the drive unit 14a of the compressor 14 and to increase the opening degree of the expansion valve 16. That is, the method for estimating the occurrence of condensation on the evaporator 17 in the drying device of the second embodiment is different from the method for estimating the occurrence of condensation on the evaporator 17 in the drying device 100 of the first embodiment.

  In the drying apparatus of the second embodiment, the temperature sensor 81 that detects the temperature on the refrigerant inlet side in the evaporator is an example of a fourth detector, and detects the temperature on the refrigerant outlet side in the evaporator 17. The temperature sensor 82 is an example of a fifth detector.

  In the control unit 90, for example, when the degree of superheat as the difference between the temperature detected by the temperature sensor 82 and the temperature detected by the temperature sensor 81 is extremely low or high with respect to the normal degree of superheat, that is, When the calculated superheat value is out of the predetermined range of the target value, a flag is first set. Based on these flags, for example, when the calculated value of the actual superheat degree deviates from the predetermined range of the target value a plurality of times during a predetermined time, as shown by the C line in FIG. The control unit 90 (see FIG. 3) can detect that the degree of superheat repeatedly rises and falls within a predetermined temperature range.

  By detecting that the actual degree of superheat repeatedly rises and falls within a predetermined temperature range, the occurrence of condensation in the evaporator 17 can be estimated. Based on this estimation, the control unit 90 (see FIG. 3) controls the heat pump device 70 so as to stop the operation of the drive unit 14a of the compressor 14 and increase the opening degree of the expansion valve 16.

  As described above, the control unit 90 (see FIG. 3) is configured to stop the operation of the drive unit 14a of the compressor 14 when the actual superheat degree repeatedly increases and decreases within a predetermined temperature range, and The heat pump device 70 is controlled to increase the opening of the expansion valve 16. By doing in this way, in the drying apparatus of 2nd Embodiment, the fall of drying efficiency is prevented by returning from the abnormal state in the viewpoint of the heat exchange rate of the heat pump apparatus 70 to an appropriate state at an early stage. Can do.

  In addition, although description is abbreviate | omitted about the structure of the control part 90 in the drying apparatus of 2nd Embodiment, it is comprised similarly to the control part 90 (refer FIG. 3) of the drying apparatus 100 of 1st Embodiment. Moreover, the calculating part 92 in the control part 90 of the drying apparatus of 2nd Embodiment also has a function which processes the calculation different from the calculation processed in the control part 90 of the drying apparatus 100 of 1st Embodiment as mentioned above. .

  As described above, the drying device according to the second embodiment includes the heat pump device 70, the temperature sensor 81, the temperature sensor 82, and the control unit 90. The heat pump device 70 includes a compressor 14 having a drive unit 14a, an expansion valve 16 that adjusts the pressure of the refrigerant, and an evaporator 17 that vaporizes the refrigerant. The temperature sensor 81 detects the temperature of the refrigerant inlet side in the evaporator 17. The temperature sensor 82 detects the temperature on the outlet side of the refrigerant in the evaporator 17. The control unit 90 controls the heat pump device 70.

  In the drying apparatus of the second embodiment, the controller 90 calculates the degree of superheat as the difference between the temperature detected by the temperature sensor 81 and the temperature detected by the temperature sensor 82 after operating the heat pump device 70. To do. The control unit 90 controls the heat pump device 70 so as to adjust the opening degree of the expansion valve 16 so that the calculated superheat value approaches a preset target value. Further, when the degree of superheat repeatedly increases and decreases within a predetermined temperature range, the control unit 90 stops the operation of the drive unit 14a and increases the opening degree of the expansion valve 16. The apparatus 70 is controlled.

  According to this configuration, in the drying apparatus 100, an appropriate state can be obtained by presuming an abnormal state (or an unfavorable state) from the viewpoint of heat exchange of the heat pump device 70, such as a state where the evaporator 17 is condensed. (Or a preferable state) can be restored early.

  That is, when the expansion valve 16 is opened when the operation of the compressor 14 is temporarily stopped, a relatively warm refrigerant staying on the condenser 15 side and a relatively cold refrigerant staying on the evaporator 17 side. The amount of heat exchanged between the refrigerant and the refrigerant in the entire heat pump device 70 shifts to an equilibrium state. Therefore, the temperature on the surface of the evaporator 17 also rises as the temperature of the refrigerant on the evaporator 17 side rises, so that condensation of the evaporator 17 can be prevented or defrosted.

  By doing in this way, the drying apparatus which can prevent that drying efficiency falls in the environment where the temperature of external air is low can be provided.

  Other configurations and operational effects of the drying device of the second embodiment are the same as those of the drying device 100 of the first embodiment. Therefore, the description of other configurations and operational effects of the drying apparatus of the second embodiment is omitted.

  The embodiment disclosed above should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above embodiments but by the scope of claims, and includes all modifications and variations within the meaning and scope equivalent to the scope of claims.

14: compressor, 14a: drive unit, 16: expansion valve, 17: evaporator, 32: drying chamber, 60, 61, 63: duct, 70: heat pump device, 81, 82, 83, 84, 85: temperature sensor , 90: control unit, 100: drying apparatus

Claims (5)

A heat pump device including a compressor having a drive unit and an expansion valve for adjusting the pressure of the refrigerant;
A drying chamber;
Between the drying chamber and the heat pump device so that the air heated by the heat pump device is supplied to the drying chamber and the air whose humidity is increased in the drying chamber is returned to the heat pump device. An air circulation path to be arranged;
A temperature detector for detecting a temperature of a predetermined portion of the heat pump device, and at least one temperature selected from the group consisting of a temperature of air flowing through the path;
A control unit for controlling the heat pump device,
The temperature detector includes a first detector and a second detector that detects a temperature at a position different from a temperature detected by the first detector;
After the operation of the heat pump device, the control unit detects that the temperature detected by the first detector is equal to or lower than a first predetermined temperature and the temperature detected by the second detector is the first temperature. A drying device that controls the heat pump device to stop the operation of the drive unit and to increase the opening of the expansion valve when the temperature is equal to or higher than a predetermined temperature of 2.   When a predetermined time has elapsed after operating the heat pump device, if the temperature detected by the first detector is equal to or lower than the first predetermined temperature, or by the second detector In any case where the detected temperature is equal to or lower than a third predetermined temperature, the control unit is configured to operate the heat pump device so that the drive unit operates at a rotational speed higher than a preset rotational speed. The drying apparatus according to claim 1, wherein the drying apparatus is controlled. The heat pump device further includes an evaporator for vaporizing the refrigerant,
The temperature detector further includes a third detector for detecting the temperature of the outlet side of the refrigerant in the evaporator,
The first detector detects the temperature of the refrigerant inlet side in the evaporator,
The control unit calculates a difference between the temperature detected by the first detector and the temperature detected by the third detector, and the calculated temperature difference approaches a preset target value. In addition, when the temperature detected by the first detector is equal to or lower than the first predetermined temperature, the alternative value set to a value smaller than the target value The expansion valve is controlled so that the value of the temperature difference approaches
The drying apparatus according to claim 1 or 2. The heat pump device further includes an evaporator for vaporizing the refrigerant,
The first detector detects the temperature of the refrigerant inlet side in the evaporator,
4. The drying apparatus according to claim 1, wherein the second detector detects a temperature of air in a portion from the drying chamber to the evaporator in the path. 5. A heat pump device including a compressor having a drive unit, an expansion valve for adjusting the pressure of the refrigerant, and an evaporator for vaporizing the refrigerant;
A fourth detector for detecting the temperature of the refrigerant inlet side in the evaporator;
A fifth detector for detecting the temperature of the outlet side of the refrigerant in the evaporator;
A control unit for controlling the heat pump device,
The controller calculates the difference between the temperature detected by the fourth detector and the temperature detected by the fifth detector after the heat pump device is operated, and the calculated temperature difference When the heat pump device is controlled to adjust the opening of the expansion valve so that the value approaches a preset target value, and the temperature difference repeats rising and falling within a predetermined temperature range Is a drying device that controls the heat pump device to stop the operation of the drive unit and to increase the opening of the expansion valve.

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