dryer

Abstract

A dryer that shortens the time of a drying process is provided. The dryer according to the present disclosure includes a housing tank that houses an object; a heat pump device that is obtained by connecting a compressor, a condenser, an expansion mechanism, and an evaporator through refrigerant piping in which a refrigerant circulates; an air duct member that demarcates an air duct between the housing tank and the heat pump device; a fan that is provided to the air duct member and circulates air between the housing tank and the heat pump device; a first sensor that is provided to the condenser and measures a first temperature of the refrigerant; and a control unit that controls the compressor and the expansion mechanism, wherein the expansion mechanism has a flow rate adjustment unit that can change the flow rate of the refrigerant flowing in, and if the first temperature exceeds a first threshold value, the control unit controls the flow rate adjustment unit in such a manner that the flow rate of the refrigerant flowing into the expansion mechanism increases.

Description

Technical Field

[0001] This disclosure relates to a dryer. Background Technology

[0002] For example, Patent Document 1 discloses a dryer that includes a heat pump unit consisting of a compressor, a condenser, an expansion unit, and an evaporator connected in a ring. The heat pump unit is used to dehumidify and heat the air inside the drying chamber to dry clothes.

[0003] The dryer described in Patent Document 1 also includes an auxiliary cooler on the air inlet side of the evaporator to cool the air flowing into the evaporator. When the operating pressure of the heat pump unit rises as drying proceeds, the auxiliary cooler cools the air flowing into the evaporator to suppress excessive rise in evaporation pressure.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-48811 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] By suppressing the rise in the operating pressure of the heat pump unit, interruptions in compressor operation can be avoided. On the other hand, if the air flowing into the evaporator is cooled as in Patent Document 1, the humidity of the air increases, potentially lengthening the drying process. Therefore, there is room for improvement in both suppressing the rise in the operating pressure of the heat pump unit and shortening the drying process time.

[0009] The purpose of this disclosure is to solve the above-mentioned problems and provide a dryer that shortens the drying process time.

[0010] Solution for solving the problem

[0011] One aspect of the dryer disclosed herein includes: a receiving tank for receiving an object; a heat pump unit that connects a compressor, a condenser, an expansion mechanism, and an evaporator via refrigerant piping for refrigerant circulation; an air duct component that defines an air duct between the receiving tank and the heat pump unit; a fan disposed on the air duct component for circulating air between the receiving tank and the heat pump unit; a first sensor disposed on the condenser for measuring a first temperature of the refrigerant; and a control unit that controls the compressor and the expansion mechanism, wherein the expansion mechanism has a flow adjustment unit capable of changing the flow rate of the incoming refrigerant, and if the first temperature exceeds a first threshold, the control unit controls the flow adjustment unit in such a way as to increase the flow rate of the refrigerant flowing into the expansion mechanism.

[0012] The effects of the invention

[0013] According to this disclosure, it is possible to provide a dryer that shortens the drying process time. Attached Figure Description

[0014] Figure 1 This is a schematic cross-sectional view of a dryer according to an embodiment of the present disclosure.

[0015] Figure 2 This is a schematic diagram of the heat pump device included in the dryer of the embodiment.

[0016] Figure 3 This is a Morrill line diagram of the heat cycle achieved through a heat pump device.

[0017] Figure 4A This is a schematic diagram of the electronic expansion valve in the expansion mechanism of a heat pump unit.

[0018] Figure 4B This is a schematic diagram of an electronic expansion valve.

[0019] Figure 5 This is a flowchart of the first action performed by the dryer in the embodiment.

[0020] Figure 6 This is an action diagram showing the first temperature and the opening degree of the electronic expansion valve in the first action.

[0021] Figure 7 This is a Morrill line diagram of the heat cycle achieved through a heat pump device.

[0022] Figure 8 This is a flowchart of the second action performed by the dryer in the embodiment.

[0023] Figure 9 This is an action diagram showing the second temperature and the opening degree of the electronic expansion valve in the second action.

[0024] Figure 10 This is a schematic cross-sectional view of the evaporator of a heat pump unit.

[0025] Figure 11 This is a flowchart of the third action performed by the dryer in the embodiment.

[0026] Figure 12 This is an action diagram showing the third temperature and the opening degree of the electronic expansion valve in the third action. Detailed Implementation

[0027] (Implementation Method 1)

[0028] The dryer 1 according to the embodiments of this disclosure will be described. The dryer 1 is a device for drying wet clothing, towels, sheets, and other items that are to be dried. In Embodiment 1, the dryer 1 is a washer-dryer (a so-called drum washer-dryer) that also has a washing function. Alternatively, the dryer 1 may not have a washing function.

[0029] Figure 1 This is a schematic cross-sectional view of the dryer 1 according to Embodiment 1 of this disclosure. Figure 2 This is a schematic diagram of the heat pump device 6 provided by the dryer 1.

[0030] exist Figure 1 In this model, two mutually orthogonal directions within the horizontal plane are designated as the width direction X and the front-back direction Y, while the vertical direction orthogonal to the horizontal plane is designated as the up-down direction Z.

[0031] like Figure 1 As shown, the dryer 1 includes a housing 2, an outer tank 3, a receiving tank 4, a drive unit 5, a heat pump device 6, an outer shell 8, an air duct component 9, a fan 10, and a control unit 12.

[0032] The housing 2 is a component that forms the exterior of the dryer 1. An opening 20 and a freely opening and closing door 21 covering the opening 20 are provided on the front surface of the housing 2.

[0033] The outer tank 3 is located inside the housing 2 and is a roughly cylindrical component that serves to collect washing water. The outer tank 3 can also be called a water tank or a tub. The outer tank 3 has an opening 31 at the position facing the opening 20 of the housing 2, and the edge of the opening 31 is connected to the opening 20 by a bellows 32.

[0034] The receiving tank 4 is disposed inside the outer tank 3 in a manner that allows it to rotate about the rotation axis V0, and is a generally cylindrical component capable of accommodating objects. The receiving tank 4 may also be referred to as a drum, inner tank, or washing tank. Multiple through holes 40 are formed in the receiving tank 4, connecting the receiving tank 4 to the outer tank 3. The receiving tank 4 has openings 41 at the opening 20 facing the housing 2 and the opening 31 of the outer tank 3. When the user of the dryer 1 opens the door 21, they can place objects into the receiving tank 4 through the openings 20, 31, and 41.

[0035] The rotation axis V0 of the receiving slot 4 extends obliquely downward toward the rear (+Y side). Alternatively, the rotation axis V0 may extend horizontally.

[0036] The drive unit 5 is a component that drives the receiving groove 4 to rotate about the rotation axis V0. The drive unit 5 may include, for example, a motor that rotates the receiving groove 4.

[0037] The heat pump unit 6 is a device that adjusts the humidity and temperature of the air passing through it. Figure 2 This is a schematic diagram of heat pump device 6. (For example...) Figure 2 As shown, the heat pump unit 6 includes a compressor 61, an expansion mechanism 62, an evaporator 63, a condenser 64, and a refrigerant piping 65. The evaporator 63, compressor 61, condenser 64, and expansion mechanism 62 are connected in sequence via refrigerant piping 65 for refrigerant circulation.

[0038] Evaporator 63 is a heat exchanger that cools the surrounding air by vaporizing the incoming refrigerant. Evaporator 63 dehumidifies the air by condensing moisture contained in the air through cooling. Evaporator 63 can also be referred to as a cooler or a dehumidifying heat exchanger. Evaporator 63, for example, has: multiple fins made of thin metal plates; and heat transfer tubes arranged to penetrate the surface of the fins and connected to refrigerant piping 65 for refrigerant flow.

[0039] The refrigerant in the evaporator 63 changes from a two-phase state of mixture of gas and liquid to a gaseous state as it flows from the refrigerant inlet to the refrigerant outlet. Therefore, the refrigerant flowing out of the evaporator 63 is delivered to the compressor 61 in a gaseous state. By suppressing the inflow of liquid into the compressor 61, malfunctions of the compressor 61 can be prevented.

[0040] The compressor 61 is a device for compressing the incoming refrigerant. Specifically, the compressor 61 has a rotary mechanism that uses the kinetic energy of the rotary mechanism to compress the refrigerant. The compressed refrigerant is then sent to the condenser 64.

[0041] The pressure of the refrigerant flowing into compressor 61 (i.e., the pressure on the low-pressure side) is set as pressure P1, and the pressure on the high-pressure side after compression is set as pressure P2. In order to suppress compressor 61 failure, an upper limit P0 is set for the high-pressure side pressure P2.

[0042] The condenser 64 is a heat exchanger that heats the surrounding air by liquefying the incoming refrigerant. The condenser 64 can also be referred to as a heater or a heating heat exchanger. The condenser 64, for example, has heat transfer tubes and multiple fins, similar to the evaporator 63.

[0043] The refrigerant in condenser 64 flows from the refrigerant inlet to the refrigerant outlet, changing from a gaseous state to a liquid state through a two-phase process. The refrigerant flowing out of condenser 64 is sent to expansion mechanism 62.

[0044] The expansion mechanism 62 is a mechanism for reducing the pressure of the refrigerant flowing into the condenser 64. In Embodiment 1, the expansion mechanism 62 includes an electronic expansion valve 66 (described later) capable of changing the flow rate of the refrigerant flowing into the expansion mechanism 62. Figure 4A, Figure 4B In addition, the expansion mechanism 62 may also have other structures, such as expansion valves or capillary tubes, that can change the flow rate of the incoming refrigerant, to replace the electronic expansion valve 66. The depressurized refrigerant is sent to the evaporator 63 and circulates within the heat pump unit 6.

[0045] Return to Figure 1 In Embodiment 1, the evaporator 63 and the condenser 64 are arranged in a front-to-back direction Y. Specifically, the evaporator 63 and the condenser 64 are arranged such that the main surface of the fins of the evaporator 63 and the condenser 64 faces the width direction X and extends in the front-to-back direction Y. Considering the airflow (refer to arrow A), the evaporator 63 is located upstream of the condenser 64, and the air passes through the evaporator 63 and the condenser 64 in sequence to be dehumidified and heated.

[0046] The heat pump unit 6 is disposed on the upper part of the housing 2. Specifically, the heat pump unit 6 is disposed above the outer tank 3.

[0047] The outer casing 8 is a component that houses the heat pump device 6. The outer casing 8 has an inlet 81 upstream of the evaporator 63 and an outlet 82 downstream of the condenser 64. In Embodiment 1, the inlet 81 and the outlet 82 are arranged in the front-rear direction Y, and air inside the outer casing 8 flows from the inlet 81 toward the outlet 82 to the rearward side (+Y side).

[0048] The air duct component 9 is disposed inside the housing 2 and defines the air duct R between the receiving tank 4 and the heat pump device 6. In embodiment 1, the air duct component 9 has a first air duct component 91 and a second air duct component 92. The first air duct component 91 connects the opening 33 provided in the outer tank 3 to the inlet 81 of the housing 8. The second air duct component 92 connects the outlet 82 of the housing 8 to the opening 34 provided in the outer tank 3.

[0049] Multiple temperature sensors 74 for measuring the temperature of the air flowing within the air duct component 9 are provided. One temperature sensor 74 is located near the opening 33 of the outer tank 3. Another temperature sensor 74 is located near the opening 34 of the outer tank 3. With this configuration, the temperature of the air upstream and downstream of the receiving tank 4 can be measured. Furthermore, the temperature sensors 74 can be located at any position on the air duct component 9, or they can be located on the outer tank 3.

[0050] A fan 10, disposed in the air duct component 9, circulates air between the housing 4 and the heat pump unit 6. The fan 10 circulates air that has passed through the housing 8 back to the housing 4 (refer to arrow A). Specifically, when the fan 10 is driven, humid air from the housing 4 flows into the housing 8 from the inlet 81 through the first air duct component 91. Air dehumidified and heated by the heat pump unit 6 returns to the housing 4 from the outlet 82 of the housing 8 through the second air duct component 92.

[0051] Fan 10 can also have any type of fan, such as an axial fan or a Sirocco fan.

[0052] In embodiment 1, the fan 10 is located downstream of the heat pump device 6.

[0053] The control unit 12 is a device for controlling the operation of the dryer 1. The control unit 12 controls the drive unit 5, heat pump device 6, and fan 10 of the dryer 1. Alternatively, the control unit 12 may include, for example, a memory (not shown) storing a program and a processing circuit (not shown) corresponding to a processor such as a CPU (Central Processing Unit), and perform the functions of the aforementioned elements by having the program executed by the processor.

[0054] Specifically, the control unit 12 controls the rotation mechanism of the compressor 61 and the electronic expansion valve of the expansion mechanism 62 in the heat pump device 6.

[0055] Next, refer to Figure 2 and Figure 3 The heat pump device 6 will be described in more detail. Figure 3 This is a Mollier chart showing the relationship between pressure P and enthalpy H in the heat cycle achieved by heat pump unit 6. Figure 3 In the diagram, line R1 represents the changes in compressor 61, line R2 represents the changes in expansion mechanism 62, line R3 represents the changes in evaporator 63, and line R4 represents the changes in condenser 64.

[0056] like Figure 2 As shown, the heat pump unit 6 also includes a first sensor 71, a second sensor 72, and a third sensor 73 for measuring the temperature of the refrigerant. Furthermore, sensors 71-73 in this specification measure the temperature of the piping supplying the refrigerant and estimate the measured piping temperature as the temperature of the refrigerant itself.

[0057] The state of the thermal cycle achieved by the heat pump device 6 can be estimated based on the temperature measured by sensors 71-73. Specifically, such as Figure 3As shown, based on the Morrill line diagram assuming an isentropic state (i.e., the compressor 61 operates at 100% efficiency), the refrigerant pressure and the refrigerant temperature at other locations can be estimated from the temperatures measured by sensors 71-73.

[0058] A first sensor 71 is disposed in the condenser 64 and is used to measure the first temperature T1 of the refrigerant in the condenser 64. In Embodiment 1, the first sensor 71 is disposed in the condenser 64 at a position where the refrigerant is in a two-phase state of liquid and gas mixture. The first sensor 71 is disposed, for example, in the center of the condenser 64.

[0059] The first temperature T1 is correlated with the pressure P2 on the high-pressure side of compressor 61. Therefore, the pressure P2 on the high-pressure side can be estimated based on the first temperature T1. Since an upper limit P0 is set for the pressure P2 on the high-pressure side, it is necessary to suppress excessive increases in the first temperature T1. Therefore, a first threshold S1 corresponding to the upper limit P0 is set for the first temperature T1. If the first temperature T1 exceeds the first threshold S1 for a specified period of time, it is necessary to stop compressor 61.

[0060] The second sensor 72 is located at the refrigerant inlet of the evaporator 63 and is used to measure the second temperature T2 of the refrigerant flowing into the evaporator 63.

[0061] The second temperature T2 is an indicator of the phase state of the refrigerant in the evaporator 63. Specifically, the pressure of the refrigerant in the evaporator 63 can be estimated based on the second temperature T2. The pressure of the refrigerant in the evaporator 63 is related to the state of the refrigerant (two-phase state or gaseous state). Therefore, the position where the refrigerant in the evaporator 63 switches from a two-phase state to a gaseous state can be estimated based on the second temperature T2.

[0062] The third sensor 73 is disposed between the compressor 61 and the condenser 64 to measure the third temperature T3 of the refrigerant discharged from the compressor 61. In Embodiment 1, the third sensor 73 is disposed at the compressor 61 on the discharge pipe of the compressor 61 that discharges refrigerant toward the condenser 64. Therefore, the third temperature T3 measured by the third sensor 73 can also be referred to as the discharge pipe temperature.

[0063] The third temperature T3 is related to the refrigerant pressure P2 on the high-pressure side of compressor 61. A fifth threshold S5 is also set for the third temperature T3. If the third temperature T3 exceeds the fifth threshold S5 for a specified period of time, compressor 61 is required to stop.

[0064] The temperature difference between the refrigerant at the refrigerant outlet and the refrigerant at the refrigerant inlet of the evaporator 63 can be estimated based on the temperature difference between the third temperature T3 and the second temperature T2. This temperature difference can also be referred to as the suction superheat (SH). Suction SH is an indicator of the heat conversion efficiency of the evaporator 63; a stable suction SH indicates that the evaporator 63 is being used efficiently. The suction SH varies depending on the operating conditions of the heat pump unit 6 and the progress of the drying process, for example, from 1°C to 10°C.

[0065] Alternatively, if the operation of compressor 61 differs significantly from the ideal isentropic state, i.e., the state of 100% operating efficiency, an additional sensor can be installed between evaporator 63 and compressor 61 to measure the temperature of the refrigerant flowing into compressor 61. In this case, the suction temperature SH is the difference between the temperature measured by the additional sensor and the second temperature T2.

[0066] Furthermore, the temperature difference between the refrigerant at the refrigerant inlet and the refrigerant at the refrigerant outlet of the condenser 64 can be estimated based on the temperature difference between the third temperature T3 and the first temperature T1. This temperature difference can also be referred to as the discharge superheat (SH). Discharge SH is an indicator of the heat conversion efficiency of the condenser 64; a stable discharge SH indicates that the condenser 64 is being used efficiently.

[0067] Figure 4A and Figure 4B This is a schematic diagram of part of the electronic expansion valve 66 of the expansion mechanism 62.

[0068] like Figure 4A and Figure 4B As shown, the electronic expansion valve 66 has a cylindrical portion 75 and a needle-shaped member 76. The cylindrical portion 75 is a cylindrical member with an opening 75A defined at its front end. The needle-shaped member 76 is a rod-shaped member with a tapered shape, which can be inserted into the cylindrical portion 75 to seal the opening 75A. The needle-shaped member 76 is movable relative to the cylindrical portion 75 along the long side direction L between a position sealing the opening 75A and a position opening the opening 75A.

[0069] The needle-shaped member 76 has a first tapered portion 77 and a second tapered portion 78 in sequence in the direction toward the top end 76A. The side surfaces of the tapered portions 77 and 78 have an inclined angle relative to the long side direction L, and the cross-sectional area of ​​the needle-shaped member 76 orthogonal to the long side direction L decreases as it moves toward the top end 76A of the needle-shaped member 76.

[0070] The tilt angle of the second tapered portion 78 is smaller than that of the first tapered portion 77. Therefore, compared with the first tapered portion 77, the rate of change of cross-sectional area per unit length in the long side direction L of the second tapered portion 78 is smaller.

[0071] In embodiment 1, the needle-shaped member 76 is movable along the long side direction L within the range of inserting the second tapered portion 78 into the opening 75A. This movement changes the distance between the side surface of the second tapered portion 78 and the edge of the cylindrical portion 75 that defines the opening 75A, thus changing the area of ​​the open opening 75A. The area of ​​the open opening 75A can also be referred to as the opening degree.

[0072] For example, when the needle-shaped part 76 is from Figure 4A Move to the position shown Figure 4B When the position is shown, the distance between the side of the second conical portion 78 and the edge of the cylindrical portion 75 of the defined opening portion 75A decreases from distance G1 to distance G2, and the opening degree of the electronic expansion valve 66 decreases. On the other hand, when the needle-shaped member 76 moves in the opposite direction, the opening degree increases.

[0073] The flow rate of refrigerant flowing into the expansion mechanism 62 through the opening 75A can be adjusted by increasing or decreasing the opening degree. If the opening degree decreases, the flow rate of refrigerant flowing into the expansion mechanism 62 also decreases; if the opening degree increases, the flow rate of refrigerant flowing into the expansion mechanism 62 also increases.

[0074] Furthermore, by moving the needle-shaped member 76 within the range of inserting the second tapered portion 78 into the opening 75A, the increase or decrease in the opening degree relative to the amount of movement in the long side direction L can be reduced compared to the case where it moves within the range of inserting the first tapered portion 77 into the opening 75A. Therefore, the opening degree can be controlled with higher precision.

[0075] The movement of the needle-shaped part 76 in the long side direction L is controlled by the control unit 12.

[0076] [Example of action: First action]

[0077] Next, the first operation will be described as an example of the operation of the dryer 1 having the above structure. Figure 5 This is the flowchart for the first action. Figure 6 This is an action diagram representing the first temperature T1 and the opening degree J of the electronic expansion valve 66 in the first action. Figure 7 The Morrill diagram shows the thermal cycle achieved by the heat pump device 6 in the first action.

[0078] like Figure 5 As shown, the control unit 12 starts the drying process according to the operation of the user of the dryer 1.

[0079] Next, the control unit 12 acquires the opening degree J of the electronic expansion valve 66 and sets it as the first opening degree J1 (S11).

[0080] In Embodiment 1, after step S11, the control unit 12 keeps the speed of the compressor 61 constant.

[0081] Next, the control unit 12 acquires the first temperature T1 of the first sensor 71 (S12). The control unit 12 may also execute step S12 simultaneously with step S11.

[0082] Next, the control unit 12 determines whether the acquired first temperature T1 exceeds the first threshold S1 (S13). The first threshold S1 is the temperature corresponding to the upper limit P0 of the pressure P2 on the high-pressure side of the compressor 61, for example, 70°C.

[0083] If the first temperature T1 is less than the first threshold S1 (which is "No" in S13), the control unit 12 returns to step S11. If the first temperature T1 is less than the first threshold S1, the control unit 12 can also control the opening degree J of the electronic expansion valve 66 based on parameters different from the first temperature T1. For example, the control unit 12 can also control the opening degree J of the electronic expansion valve 66 based on the intake SH.

[0084] If the first temperature T1 exceeds the first threshold S1 ("yes" in S13), the control unit 12 determines whether the opening degree J of the electronic expansion valve 66 has been increased (S14). Specifically, the control unit 12 determines whether the increase in opening degree J after step S13 is the first increase or the increase in opening degree J after the second increase. The control unit 12 may also refer to a memory (not shown) for example to make the determination.

[0085] If the initial opening J increases ("No" in S14), then the control unit 12 increases the opening J of the electronic expansion valve 66 by a first increase amount ΔJ1 (S15). Figure 6 As shown, the control unit 12 increases the opening J of the electronic expansion valve 66 from a first opening J1 to a second opening J2 by ​​a first increase ΔJ1. In Embodiment 1, the control unit 12 immediately increases the opening J to the second opening J2 after making a determination.

[0086] In Implementation 1, the first increase ΔJ1 is a predetermined value, but it can also be a value determined based on the obtained first temperature T1.

[0087] By increasing the opening J of the electronic expansion valve 66, the flow rate of refrigerant flowing into the expansion mechanism 62 increases. Therefore, as Figure 7As shown, in the expansion mechanism 62, the refrigerant pressure reduction decreases (the length of line R2). If the pressure reduction decreases, the pressure difference between the high-pressure side (line R4) and the low-pressure side (line R3) decreases, and the pressure P2 on the high-pressure side drops. Therefore, the pressure P2 on the high-pressure side becomes less than the upper limit P0, allowing the compressor 61 to continue operating.

[0088] If the opening J increases after the second time ("Yes" in S14), the control unit 12 increases the opening J of the electronic expansion valve 66 by a second increase amount ΔJ2 within a predetermined time (S16). By further executing step S16 after step S15, even if the first temperature T1 has not decreased sufficiently by the first increase amount ΔJ1, the first temperature T1 can be decreased by increasing the opening J of the electronic expansion valve 66 in stages.

[0089] In Implementation 1, the second increase ΔJ2 is determined based on the obtained first temperature T1. Specifically, the control unit 12 determines the second increase ΔJ2 based on the difference between the first temperature T1 and the first threshold S1. On the other hand, the second increase ΔJ2 can also be a predetermined value.

[0090] like Figure 6 As shown, in Embodiment 1, the second increase ΔJ2 is smaller than the first increase ΔJ1. This structure helps to suppress excessive decreases in the pressure P2 on the high-pressure side. Furthermore, the change in the opening J per unit time in step S16 is smaller than the change in step S15.

[0091] Next, as Figure 5 As shown, the control unit 12 acquires the first temperature T1 of the first sensor 71 again (S17).

[0092] Next, the control unit 12 determines whether the acquired first temperature T1 is lower than the second threshold S2 (S18). The second threshold S2 is a temperature lower than the first threshold S1, for example, 68°C.

[0093] If the first temperature T1 is not lower than the second threshold S2 (which is "No" in S18), the control unit 12 directly proceeds to step S101.

[0094] If the first temperature T1 is lower than the second threshold S2 ("yes" in S18), the control unit 12 reduces the opening J of the electronic expansion valve 66 (S19). Figure 6 As shown, the control unit 12 reduces the opening J of the electronic expansion valve 66 to a third opening J3 within a specified time. In Embodiment 1, the third opening J3 is smaller than the first opening J1.

[0095] Furthermore, the control unit 12 can also immediately reduce the opening J to the third opening J3 after the determination. Alternatively, the third opening J3 can also be the first opening J1 or higher.

[0096] Next, as Figure 5 As shown, the control unit 12 determines whether the drying time has elapsed (S101).

[0097] If the drying time has not been completed (in S101, this is "No"), the control unit 12 returns to step S14. By repeatedly performing steps S14 to S17, the control unit 12 can increase the opening J of the electronic expansion valve 66 in stages by a second increase amount ΔJ2 until the first temperature T1, which is above the first threshold S1, is lower than the second threshold S2.

[0098] If the drying time has elapsed (in S101, it is "Yes"), then the control unit 12 ends the first action.

[0099] [Example of action: Second action]

[0100] Next, the second operation will be described as an example of other operations of the dryer 1. Figure 8 This is the flowchart for the second action. Figure 9 This is an action diagram representing the second temperature T2 and the opening degree J of the electronic expansion valve 66 in the second action. Figure 10 This is a schematic cross-sectional view of evaporator 63.

[0101] Based on the user's operation of the dryer 1, the control unit 12 begins the drying process. Therefore, as Figure 8 As shown, the control unit 12 performs the first control. In the first control, firstly, the control unit 12 acquires the opening degree J of the electronic expansion valve 66 and sets it to the fourth opening degree J4 (S21).

[0102] Next, the control unit 12 determines whether the current time point is the second half of the drying process (S22). In this specification, the "second half" of the drying process refers to the drying process after the time point when the amount of moisture evaporated from the object in the receiving tank 4 is at its maximum.

[0103] The control unit 12 indirectly determines the time point when the amount of moisture evaporated from the object is at its maximum. Specifically, if at least one of the first, second, and third predetermined conditions is met, the control unit 12 determines that the current time point is after the time point when the amount of moisture evaporated from the object is at its maximum. The first predetermined condition is that the air temperature or temperature difference measured by the temperature sensor 74 installed on the air duct component 9 is below a predetermined value. The second predetermined condition is that the rotational speed of the compressor 61 is below a predetermined value. The third predetermined condition is that the third temperature T3 measured by the third sensor 73 is above a predetermined value.

[0104] In Implementation 1, if all of the first, second, and third specified conditions are met, the control unit 12 determines that the current time point is the latter half of the drying process. Alternatively, if at least one of the first, second, and third specified conditions is met, the control unit 12 determines that the current time point is the latter half of the drying process.

[0105] If it is not the latter half of the drying process ("No" in S22), then the control unit 12 returns to step S21.

[0106] If it is the latter half of the drying process ("Yes" in S22), the control unit 12 switches from the first control to the second control. Alternatively, the control unit 12 can also perform other steps in the first control.

[0107] In the second control, firstly, the control unit 12 reduces the opening degree J of the electronic expansion valve 66 (S23). By reducing the opening degree J of the electronic expansion valve 66, the opening degree J of the electronic expansion valve 66 in the second control is less than the opening degree J in the first control. Figure 9 As shown, the control unit 12 reduces the opening J of the electronic expansion valve 66 from the fourth opening J4 to the fifth opening J5 within a specified time. The fifth opening J5 is a predetermined value.

[0108] By reducing the opening J of the electronic expansion valve 66, the flow rate of refrigerant flowing into the expansion mechanism 62 is reduced. Therefore, in the expansion mechanism 62, the pressure P1 on the low-pressure side of the compressor 61 decreases, and the temperature of the refrigerant at the refrigerant inlet of the evaporator 63 (i.e., the second temperature T2) decreases, maintaining the dew point temperature of the refrigerant near the refrigerant inlet of the evaporator 63 relative to the air. In this state, the air passing near the refrigerant inlet of the evaporator 63 can be dehumidified.

[0109] In Embodiment 1, after the control unit 12 reduces the opening J of the electronic expansion valve 66, it maintains the fifth opening J5 for a predetermined time.

[0110] Next, as Figure 8 As shown, the control unit 12 acquires the second temperature T2 of the second sensor 72 (S24).

[0111] Next, the control unit 12 determines whether the acquired second temperature T2 exceeds the third threshold S3 (S25).

[0112] If the second temperature T2 exceeds the third threshold S3 (which is "yes" in S25), the control unit 12 reduces the opening J of the electronic expansion valve 66 (S26). By reducing the opening J of the electronic expansion valve 66, the flow rate of refrigerant flowing into the electronic expansion valve 66 is reduced, the pressure P1 on the low-pressure side of the compressor 61 decreases, and the second temperature T2 decreases.

[0113] If the second temperature T2 does not exceed the third threshold S3 (which is "No" in S25), the control unit 12 increases the opening degree J of the electronic expansion valve 66 (S27). By increasing the opening degree J of the electronic expansion valve 66, the flow rate of refrigerant flowing into the electronic expansion valve 66 increases, the pressure P1 on the low-pressure side of the compressor 61 rises, and the second temperature T2 rises.

[0114] In step S27, when the opening J of the electronic expansion valve 66 is increased, the control unit 12 maintains the opening J at or below the fourth opening J4 in the first control. Specifically, the control unit 12 maintains the opening J at or below the minimum value of the fourth opening J4 in the first control.

[0115] Through steps S25 to S27, the control unit 12 can adjust the opening degree J of the electronic expansion valve 66 to bring the second temperature T2 close to the third threshold S3. In Embodiment 1, the third threshold S3 is the temperature at which the refrigerant in at least a portion of the evaporator 63 is in a two-phase state. That is, the control unit 12 can adjust the opening degree J of the electronic expansion valve 66 to bring the second temperature T2 close to the third threshold S3, thereby maintaining the refrigerant in at least a portion of the evaporator 63 in a two-phase state.

[0116] like Figure 10 As shown, the evaporator 63 has multiple rows 93-95. Each of the multiple rows 93-95 has multiple fins 98 arranged in the width direction X and a heat transfer tube 99 extending through the multiple fins 98 in the width direction X. The heat transfer tubes 99 of each of the multiple rows 93-95 are connected in series.

[0117] Columns 93-95 represent the airflow relative to arrow A, flowing from upstream to downstream, i.e. from the inlet 81 of the outer casing 8 to the outlet 82 (see reference). Figure 1 Arrange them sequentially. If airflow is taken into account, then arrange the second column 94 downstream of the first column 93, and arrange the third column 95 downstream of the second column 94.

[0118] On the other hand, as indicated by arrow B, the refrigerant passes through each heat transfer tube 99 from the expansion mechanism 62 in the order of the third column 95, the second column 94, and the first column 93. Therefore, considering the flow of the refrigerant, the second column 94 is arranged downstream of the third column 95, and the first column 93 is arranged downstream of the second column 94.

[0119] The control unit 12 can adjust the second temperature T2 by adjusting the opening degree J of the electronic expansion valve 66, thereby adjusting the state of the refrigerant in each of the multiple columns 93 to 95.

[0120] As the refrigerant moves from column 3 (95) to column 1 (93), it changes from a two-phase state to a gaseous state.

[0121] In Embodiment 1, when the second temperature T2 is the third threshold S3, all the refrigerant in the third column 95 becomes a two-phase state, while the refrigerant in columns 94 and 93 becomes a gaseous state. With this structure, a two-phase state can be maintained in the third column 95, thus enabling dehumidification of the air through the third column 95. On the other hand, since the air is not dehumidified in columns 94 and 93, no dehumidifying water adheres to them. Therefore, after the drying process is completed, the drying process of the evaporator 63 can be shortened.

[0122] If the second temperature T2 exceeds the third threshold S3, the range of the refrigerant in a two-phase state expands, and dehumidifying water adheres to columns 94 and 93. On the other hand, if the second temperature T2 is lower than the third threshold S3, the range of the refrigerant in a two-phase state decreases, and the dehumidification function of the evaporator 63 is excessively reduced.

[0123] Furthermore, the third threshold S3 is not limited to the setting described above. The third threshold S3 can also be set such that less than half of the volume of the second column 94 (excluding the third column 95) is in a two-phase state. Alternatively, the third threshold S3 can also be set such that at least a portion of the refrigerant in the third column 95 is in a two-phase state.

[0124] In steps S26 and S27, when the opening degree J of the electronic expansion valve 66 is changed, the control unit 12 maintains the rotational speed of the compressor 61.

[0125] Additionally, in steps S26 and S27, the control unit 12 can also acquire the third temperature T3 measured by the third sensor 73, and determine the change in opening J (i.e., the change in flow rate) in steps S26 and S27 based on the third temperature T3. For example, the control unit 12 can also determine the change in opening J based on the difference between the third temperature T3 and the fifth threshold S5. For instance, if the difference between the third temperature T3 and the fifth threshold S5 is large, the control unit 12 can increase the change in opening J.

[0126] Next, as Figure 8 As shown, the control unit 12 determines whether the drying time has elapsed (S28). If the drying time has not elapsed ("No" in S28), the control unit 12 returns to step S25 and repeats the operation. If the drying time has elapsed ("Yes" in S28), the control unit 12 ends the second operation.

[0127] [Example of action: Third action]

[0128] Next, the third operation will be described as an example of other operations of the dryer 1. Figure 11 This is the flowchart for the third action. Figure 12 This is an action diagram representing the third temperature T3 and the opening degree J of the electronic expansion valve 66 in the third action.

[0129] Based on the user's operation of the dryer 1, the control unit 12 begins the drying process. Therefore, as Figure 11 As shown, the control unit 12 performs the third control.

[0130] In the third control, firstly, the control unit 12 controls the opening degree J of the electronic expansion valve 66 based on one or more parameters that include parameters different from the third temperature T3. For example, the control unit 12 may also control the opening degree J of the electronic expansion valve 66 based on the rotational speed of the compressor 61. The control unit 12 may also control the opening degree J of the electronic expansion valve 66 based on the suction SH calculated according to the second temperature T2 and the third temperature T3. The control unit 12 may also control the opening degree J of the electronic expansion valve 66 based on the discharge SH calculated according to the first temperature T1 and the third temperature T3.

[0131] Next, the control unit 12 determines whether the current time point is the second half of the drying process (S32). In Embodiment 1, the control unit 12 performs the determination in step S32 in the same way as step S22 of the second operation.

[0132] If it is not the latter half of the drying process ("No" in S32), the control unit 12 will execute step S32 again after a specified time has elapsed.

[0133] If it is the latter half of the drying process (marked as "Yes" in S32), then the control unit 12 switches from the third control to the fourth control. Alternatively, the control unit 12 can also perform other steps in the third control.

[0134] In the fourth control, firstly, the control unit 12 acquires the third temperature T3 (S33) from the third sensor 73.

[0135] Next, the control unit 12 determines whether the acquired third temperature T3 exceeds the fourth threshold S4 (S34). The fourth threshold S4 is a temperature lower than the fifth threshold S5 corresponding to the upper limit P0 of the pressure P2 on the high-pressure side of the compressor 61.

[0136] If the third temperature T3 exceeds the fourth threshold S4 (which is "yes" in S34), the control unit 12 increases the opening degree J of the electronic expansion valve 66 (S35). By increasing the opening degree J of the electronic expansion valve 66, the flow rate of cold refrigerant flowing into the compressor 61 increases, thereby cooling the compressor 61. Therefore, the rise in the third temperature T3 of the refrigerant flowing out of the compressor 61 can be suppressed.

[0137] like Figure 12 As shown, the control unit 12 increases the opening J of the electronic expansion valve 66 by a fourth increment ΔJ4 within a specified time. The fourth increment ΔJ4 can also be determined based on the third temperature T3.

[0138] like Figure 11 As shown, if the third temperature T3 does not exceed the fourth threshold S4 (in S34 it is "No"), the control unit 12 maintains the opening degree J of the electronic expansion valve 66 (S36).

[0139] Following step S35, the control unit 12 acquires the third temperature T3 from the third sensor 73 again (S37).

[0140] Next, the control unit 12 determines whether the acquired third temperature T3 exceeds the fifth threshold S5 (S38). The fifth threshold S5 corresponds to the upper limit P0 of the pressure P2 on the high-pressure side of the compressor 61.

[0141] If the third temperature T3 exceeds the fifth threshold S5 (which is "yes" in S38), the control unit 12 increases the opening degree J of the electronic expansion valve 66 (S39).

[0142] like Figure 12 As shown, the control unit 12 increases the opening J of the electronic expansion valve 66 by a fifth increment ΔJ5 within a specified time. The fifth increment ΔJ5 can also be determined based on the third temperature T3 and is larger than the fourth increment ΔJ4. In addition, the change in the opening J per unit time in step S39 is larger than the change in step S35.

[0143] like Figure 11 As shown, if the third temperature T3 does not exceed the fifth threshold S5 (which is "No" in S38), the control unit 12 maintains the opening degree J of the electronic expansion valve 66 (S36).

[0144] Next, the control unit 12 determines whether the drying time has elapsed (S40). If the drying time has not elapsed ("No" in S40), the control unit 12 returns to step S33 and repeats the above operation. If the drying time has elapsed ("Yes" in S40), the control unit 12 ends the third operation.

[0145] Before step S40, the control unit 12 may also acquire the third temperature T3 from the third sensor 73 and determine whether the acquired third temperature T3 is lower than the sixth threshold S6. The sixth threshold S6 is less than the fourth threshold S4. If the third temperature T3 is lower than the sixth threshold S6, the control unit 12 may switch from the fourth control to other control that controls the opening degree J of the electronic expansion valve 66 based on the same parameters as the third control.

[0146] The dryer 1 according to Embodiment 1 can achieve the following effects.

[0147] [Effect 1]

[0148] The dryer 1 according to Embodiment 1 includes: a receiving tank 4 for receiving an object; a heat pump device 6; an air duct member 9 for defining an air duct between the receiving tank 4 and the heat pump device 6; and a fan 10 provided on the air duct member 9 to circulate air between the receiving tank 4 and the heat pump device 6. The heat pump device 6 connects a compressor 61, a condenser 64, an expansion mechanism 62, and an evaporator 63 via a refrigerant piping 65 for refrigerant circulation. The dryer 1 also includes: a first sensor 71 provided on the condenser 64 for measuring a first temperature T1 of the refrigerant; and a control unit 12 for controlling the compressor 61 and the expansion mechanism 62. The expansion mechanism 62 has an electronic expansion valve 66 (flow adjustment unit) capable of changing the flow rate of the refrigerant flowing into it. If the first temperature T1 exceeds a first threshold S1, the control unit 12 controls the electronic expansion valve 66 in a manner that increases the flow rate of the refrigerant flowing into the expansion mechanism 62.

[0149] With this structure, the opening J of the electronic expansion valve 66 is increased to reduce the pressure reduction, thereby reducing the pressure P2 on the high-pressure side based on the pressure difference of the compressor 61. Therefore, it is possible to prevent the high-pressure side pressure P2 from reaching the design upper limit P0 of the compressor 61, allowing the compressor 61 to continue operating. Consequently, compared to stopping the compressor 61, the drying process time can be shortened.

[0150] Furthermore, in the dryer 1 according to Embodiment 1, if the first temperature T1 exceeds the first threshold S1, the control unit 12 controls the electronic expansion valve 66 to increase the flow rate of the refrigerant flowing into the expansion mechanism 62 by a first increase amount ΔJ1.

[0151] This structure can prevent the pressure P2 on the high-pressure side from reaching its upper limit P0.

[0152] Furthermore, in the dryer 1 according to Embodiment 1, after the control unit 12 controls the electronic expansion valve 66 with a first increase amount ΔJ1, if the first temperature T1 exceeds the first threshold S1, it determines a second increase amount ΔJ2 based on the first temperature T1. The control unit 12 controls the electronic expansion valve 66 in such a way that the flow rate of the refrigerant flowing into the expansion mechanism 62 increases by the second increase amount ΔJ2.

[0153] With this structure, it is possible to more reliably prevent the pressure P2 on the high-pressure side from reaching the upper limit P0.

[0154] Furthermore, in the dryer 1 according to Embodiment 1, if the first temperature T1 is lower than the second threshold S2 which is lower than the first threshold S1, the control unit 12 controls the electronic expansion valve 66 in a manner that reduces the flow rate of refrigerant flowing into the expansion mechanism 62.

[0155] This structure can suppress excessive decrease in pressure P2 on the high-pressure side, thereby suppressing the reduction in drying function. Furthermore, by making the second threshold S2 lower than the first threshold S1, hysteresis can be suppressed.

[0156] [Effect 2]

[0157] The dryer 1 according to Embodiment 1 includes: a receiving tank 4 for receiving an object; a heat pump device 6; an air duct component 9 for defining an air duct between the receiving tank 4 and the heat pump device 6; and a fan 10 provided on the air duct component 9 to circulate air between the receiving tank 4 and the heat pump device 6. The heat pump device 6 connects a compressor 61, a condenser 64, an expansion mechanism 62, and an evaporator 63 via a refrigerant piping 65 for refrigerant circulation. The dryer 1 also includes: a second sensor 72 for measuring a second temperature T2 of the refrigerant flowing into the evaporator 63; and a control unit 12 for controlling the compressor 61 and the expansion mechanism 62. The expansion mechanism 62 has an electronic expansion valve 66 (flow adjustment unit) capable of changing the flow rate of the flowing refrigerant. The control unit 12 is capable of performing a first control and a second control, wherein, in the second control, the electronic expansion valve 66 is controlled in such a way that the flow rate of the refrigerant flowing into the expansion mechanism 62 is reduced relative to the first control. If the specified conditions are met, the control unit 12 switches from the first control to the second control. In the second control, if the second temperature T2 exceeds the third threshold S3 (threshold), the control unit 12 controls the electronic expansion valve 66 in a manner that reduces the flow rate of refrigerant flowing into the expansion mechanism 62.

[0158] This structure reduces the opening degree J of the electronic expansion valve 66, increasing the refrigerant flow rate. This causes a decrease in pressure on the low-pressure side and a drop in the refrigerant temperature at the refrigerant inlet of the evaporator 63, maintaining the two-phase state of the refrigerant near the refrigerant inlet of the evaporator 63. It also dehumidifies the air passing near the refrigerant inlet of the evaporator 63, maintaining the dehumidification capacity of the evaporator 63. Therefore, the drying process time can be shortened.

[0159] Furthermore, in the dryer 1 according to Embodiment 1, in the second control, if the second temperature T2 is below the third threshold S3, the control unit 12 controls the electronic expansion valve 66 in a manner that increases the flow rate of the refrigerant flowing into the expansion mechanism 62.

[0160] With this structure, it is possible to prevent all refrigerant from becoming gaseous in the evaporator 63, and to prevent excessive reduction of the dehumidification function of the evaporator 63.

[0161] Furthermore, in the dryer 1 according to Embodiment 1, in the second control, when the electronic expansion valve 66 is controlled in such a way that the flow rate of refrigerant flowing into the expansion mechanism 62 is increased when the second temperature T2 is below the third threshold S3, the control unit 12 maintains the rotational speed of the compressor 61.

[0162] With this structure, the control of the electronic expansion valve 66 becomes simpler.

[0163] In addition, in the dryer 1 according to Embodiment 1, the specified conditions include at least one of the following: the temperature of the air measured by the temperature sensor 74 (fourth sensor) installed on the air duct component 9 is below a specified value; the rotational speed of the compressor 61 is below a specified value; and the temperature of the refrigerant measured by the third sensor 73 is above a specified value.

[0164] With this structure, the control unit 12 can determine whether the current time point is the second half of the drying process.

[0165] [Effect 3]

[0166] The dryer 1 according to Embodiment 1 includes: a receiving tank 4 for receiving an object; a heat pump device 6; an air duct component 9 for defining an air duct between the receiving tank 4 and the heat pump device 6; and a fan 10 provided in the air duct component 9 for circulating air between the receiving tank 4 and the heat pump device 6. The heat pump device 6 connects a compressor 61, a condenser 64, an expansion mechanism 62, and an evaporator 63 via a refrigerant piping 65 for refrigerant circulation. The dryer 1 also includes: a third sensor 73 provided between the compressor 61 and the condenser 64 for measuring a third temperature T3 of the refrigerant; and a control unit 12 for controlling the compressor 61 and the expansion mechanism 62. The expansion mechanism 62 has an electronic expansion valve 66 (flow adjustment unit) capable of changing the flow rate of the refrigerant flowing into it. If the third temperature T3 exceeds a fourth threshold S4, the control unit 12 controls the electronic expansion valve 66 in a manner that increases the flow rate of the refrigerant flowing into the expansion mechanism 62.

[0167] With this structure, the opening degree J of the electronic expansion valve 66 is increased, thereby increasing the refrigerant flow rate. This increases the flow of cold refrigerant into the compressor 61, cooling the compressor 61. Therefore, the rise in the third temperature T3 of the refrigerant exiting the compressor 61 can be suppressed, allowing the compressor 61 to continue operating. Consequently, compared to the case where the rise in the third temperature T3 of the refrigerant is suppressed and the compressor 61 is stopped, the drying process time can be shortened.

[0168] Furthermore, in the dryer 1 according to Embodiment 1, if the third temperature T3 exceeds the fourth threshold S4, the control unit 12 controls the electronic expansion valve 66 to increase the flow rate of the refrigerant flowing into the expansion mechanism 62 by a fifth increase ΔJ5.

[0169] With this structure, it is possible to more reliably prevent the pressure P2 on the high-pressure side of the compressor 61 from reaching the design upper limit P0.

[0170] Furthermore, in the dryer 1 according to Embodiment 1, if the third temperature exceeds a fifth threshold which is greater than the fourth threshold, the control unit controls the electronic expansion valve 66 in a manner that increases the flow rate of refrigerant flowing into the expansion mechanism.

[0171] With this structure, it is possible to more reliably prevent the pressure P2 on the high-pressure side of the compressor 61 from reaching the design upper limit P0.

[0172] Furthermore, in the dryer 1 according to Embodiment 1, the control unit is capable of performing a third control and a fourth control. In the fourth control, if the third temperature T3 exceeds the fourth threshold S4, the electronic expansion valve 66 is controlled to increase the flow rate of refrigerant flowing into the expansion mechanism 62. If a predetermined condition is met, the control unit 12 switches from the first control to the fourth control.

[0173] With this structure, compared to the case where only the fourth control can be performed, it is possible to suppress the excessive decrease of the pressure P2 on the high-pressure side and suppress the reduction of the drying function.

[0174] In addition, in the dryer 1 according to Embodiment 1, the specified conditions include at least one of the following: the temperature of the air measured by the temperature sensor 74 (fourth sensor) installed on the air duct component 9 is below a specified value; the rotational speed of the compressor 61 is below a specified value; and the temperature of the refrigerant measured by the third sensor 73 is above a specified value.

[0175] With this structure, the control unit 12 can determine whether the current time point is the second half of the drying process.

[0176] Furthermore, the dryer 1 according to Embodiment 1 also includes a second sensor 72, which is disposed between the evaporator 63 and the expansion mechanism 62, for measuring the second temperature T2 of the refrigerant. In the third control, the control unit 12 controls the electronic expansion valve 66 based on the second temperature T2.

[0177] With this structure, the heat exchange efficiency of the evaporator 63 is improved by using the SH-controlled heat pump device 6, thereby making it easier to improve the drying function in the third control.

[0178] Furthermore, the dryer 1 according to Embodiment 1 also includes a first sensor 71, which is disposed in the condenser 64 and is capable of detecting a first temperature T1 of the refrigerant. In the third control, the control unit 12 controls the electronic expansion valve 66 based on the first temperature T1.

[0179] With this structure, the heat exchange efficiency of the condenser 64 is improved based on the exhaust SH control heat pump device 6, thereby making it easier to improve the drying function in the third control.

[0180] Furthermore, in the dryer 1 according to Embodiment 1, in the third control, the control unit 12 controls the electronic expansion valve 66 based on the rotational speed of the compressor 61.

[0181] This structure improves the efficiency of compressor 61, thereby making it easier to enhance the drying function in the third control.

[0182] Furthermore, this disclosure is not limited to the above-described embodiments and can be implemented in various other ways.

[0183] Furthermore, in Embodiment 1, an example was described where the control unit 12 increases the opening degree J of the electronic expansion valve 66, but this is not a limitation. The expansion mechanism 62 can be any mechanism that can be controlled by the control unit 12 and can change the flow rate of refrigerant flowing into the expansion mechanism 62. For example, if the expansion mechanism 62 has a capillary tube that defines multiple paths, the control unit 12 can also change the flow rate of refrigerant flowing into the expansion mechanism 62 by changing the number of paths that are opened.

[0184] Furthermore, in Embodiment 1, an example was described where the needle-shaped member 76 of the electronic expansion valve 66 has two tapered portions 77 and 78, but this is not a limitation. For example, the needle-shaped member 76 may have only one tapered portion, or it may have other shapes.

[0185] In addition, the dryer 1 may also have a pressure sensor instead of the temperature sensors 71-73.

[0186] Furthermore, in Embodiment 1, an example of a dryer 1 having a second sensor 72 was described, but it is not limited to this. The dryer 1 may also have only a first sensor 71 and a third sensor 73.

[0187] Furthermore, in the first operation of Embodiment 1, an example of the control unit 12 maintaining the speed of the compressor 61 at a constant speed was described, but the operation is not limited to this. If the opening J of the electronic expansion valve 66 reaches the maximum designed opening, the control unit 12 can reduce the speed of the compressor 61, or it can stop the compressor 61 from operating.

[0188] In the first operation, if the first temperature T1 exceeds the first threshold S1 in step S13 (which is "yes" in S13), the control unit 12 reduces the speed of the compressor 61 before increasing the opening J of the electronic expansion valve 66. This operation allows for a more reliable reduction of the first temperature T1. If the first temperature T1 still exceeds the first threshold S1 even after reducing the speed of the compressor 61, the control unit 12 increases the opening J of the electronic expansion valve 66.

[0189] Alternatively, in the first operation, after increasing the opening J of the electronic expansion valve 66 by a first increase ΔJ1 or a second increase ΔJ2, if the first temperature T1 obtained in step S17 exceeds the first threshold S1, the control unit 12 reduces the speed of the compressor 61. Furthermore, if the first temperature T1 is not lower than the second threshold S2 in step S18 (which is "No" in S18), the control unit 12 reduces the speed of the compressor 61.

[0190] Furthermore, in Embodiment 1, an example was described in which the opening J was increased by a first increase amount ΔJ1 and then by a second increase amount ΔJ2 in the first operation, but this is not a limitation. For example, it is also possible that after the opening J is increased by the first increase amount ΔJ1, the control unit 12 maintains the opening J until the first temperature T1 is lower than the second threshold S2.

[0191] Furthermore, in Embodiment 1, an example was described in which the control unit 12 increases the actual first opening degree J1 obtained in step S11 in step S15 during the first operation, but this is not a limitation. For example, the control unit 12 may store a target value for the opening degree J, and in step S15, increase the opening degree J of the electronic expansion valve 66 relative to the target value.

[0192] Furthermore, in Embodiment 1, an example of an evaporator 63 having three columns was described, but it is not limited to this. The evaporator 63 may have two or more columns in which heat transfer tubes 99 are connected in series and arranged in the direction of air flow.

[0193] Furthermore, in Embodiment 1, an example was described of controlling the opening J of the electronic expansion valve 66 in a way that brings the second temperature T2 close to the third threshold S3 during the second operation, but this is not a limitation. The control unit 12 may also omit steps S24 to S25 in the latter half of the drying process, thereby reducing the opening J of the electronic expansion valve 66 by lowering the second temperature T2.

[0194] Furthermore, in Embodiment 1, an example was described in which the control unit 12 determines whether the third temperature T3 exceeds the threshold based on both the fourth threshold S4 and the fifth threshold S5 during the third operation, but this is not a limitation. The control unit 12 may also determine whether the third temperature T3 exceeds the threshold based on either the fourth threshold S4 or the fifth threshold S5.

[0195] The dryer of the first type includes: a receiving tank for receiving an object; a heat pump unit that connects a compressor, a condenser, an expansion mechanism, and an evaporator via refrigerant piping for refrigerant circulation; an air duct component that defines an air duct between the receiving tank and the heat pump unit; a fan disposed on the air duct component for circulating air between the receiving tank and the heat pump unit; a first sensor disposed on the condenser for measuring a first temperature of the refrigerant; and a control unit that controls the compressor and the expansion mechanism, wherein the expansion mechanism has a flow adjustment unit capable of changing the flow rate of the incoming refrigerant, and if the first temperature exceeds a first threshold, the control unit controls the flow adjustment unit in such a way as to increase the flow rate of the refrigerant flowing into the expansion mechanism.

[0196] Regarding the dryer of the second type, in the dryer of the first type, if the first temperature exceeds the first threshold, the control unit controls the flow adjustment unit to increase the flow rate of the refrigerant flowing into the expansion mechanism by a first increase.

[0197] Regarding the third-party type dryer, in the second type of dryer, after the control unit controls the flow adjustment unit with a first increase, if the first temperature exceeds a first threshold, it determines a second increase based on the first temperature and controls the flow adjustment unit in such a way that the flow rate of the refrigerant flowing into the expansion mechanism increases by the second increase.

[0198] Regarding the fourth type of dryer, in any of the first to third types of dryers, if the first temperature is lower than a second threshold that is lower than the first threshold, the control unit controls the flow adjustment unit in a manner that reduces the flow rate of refrigerant flowing into the expansion mechanism.

[0199] Regarding the fifth type of dryer, in any of the first to fourth types of dryers, if the first temperature exceeds the first threshold, the control unit reduces the speed of the compressor. After reducing the speed of the compressor, if the first temperature exceeds the first threshold, the control unit controls the flow adjustment unit to increase the flow rate of the refrigerant flowing into the expansion mechanism.

[0200] Regarding the sixth type of dryer, in any of the first to fifth types of dryers, if the first temperature exceeds the first threshold, the control unit controls the flow adjustment unit in a manner that increases the flow rate of refrigerant flowing into the expansion mechanism. After controlling the flow adjustment unit, if the first temperature exceeds the first threshold, the control unit reduces the speed of the compressor.

[0201] This disclosure has been fully described with reference to the accompanying drawings and in connection with preferred embodiments, but various modifications and variations will be apparent to those skilled in the art. Such modifications and variations are to be understood as included therein, provided they do not depart from the scope of the invention as defined in the appended claims.

[0202] Industrial availability

[0203] The dryer disclosed herein can shorten the drying process time, and is therefore useful as a household clothes dryer, a commercial clothes dryer, any type of wash dryer (e.g., a household drum washer-dryer, a vertical washer-dryer), or other clothes processing machines with drying functions.

[0204] Explanation of reference numerals in the attached figures

[0205] 1. Dryer

[0206] 2. Shell

[0207] 3. Outer groove

[0208] 4 Reception Containers

[0209] 6. Heat pump unit

[0210] 8. Outer shell

[0211] 9. Air duct components

[0212] 10 fans

[0213] 61 Compressor

[0214] 62 Expansion Mechanism

[0215] 63 Evaporator

[0216] 64 Condenser

[0217] 65 Refrigerant piping

[0218] 66 Electronic expansion valve

[0219] 71 First Sensor

[0220] 72 Second Sensor

[0221] 73 Third Sensor

Claims

1. A dryer, comprising: A containment tank, which contains objects. A heat pump device is formed by connecting a compressor, condenser, expansion mechanism and evaporator through refrigerant piping for refrigerant circulation; A duct component that defines an air duct between the receiving tank and the heat pump unit; A fan, which is disposed in the air duct component, is used to circulate air between the receiving tank and the heat pump device; A first sensor, which is disposed in the condenser, is used to measure the first temperature of the refrigerant; as well as The control unit controls the compressor and the expansion mechanism. The expansion mechanism includes a flow adjustment section capable of changing the flow rate of the incoming refrigerant. If the first temperature exceeds the first threshold, the control unit controls the flow adjustment unit in a manner that increases the flow rate of refrigerant flowing into the expansion mechanism.

2. The dryer according to claim 1, wherein, If the first temperature exceeds the first threshold, the control unit controls the flow adjustment unit to increase the flow rate of the refrigerant flowing into the expansion mechanism by a first increase.

3. The dryer according to claim 2, wherein, After controlling the flow adjustment unit with the first increase, if the first temperature exceeds the first threshold, the control unit determines a second increase based on the first temperature and controls the flow adjustment unit to increase the flow rate of refrigerant flowing into the expansion mechanism by the second increase.

4. The dryer according to any one of claims 1 to 3, wherein, If the first temperature is lower than a second threshold that is lower than the first threshold, the control unit controls the flow adjustment unit in a manner that reduces the flow rate of refrigerant flowing into the expansion mechanism.

5. The dryer according to any one of claims 1 to 3, wherein, If the first temperature exceeds the first threshold, the control unit reduces the speed of the compressor. After reducing the speed of the compressor, if the first temperature exceeds the first threshold, the control unit controls the flow adjustment unit to increase the flow rate of refrigerant flowing into the expansion mechanism.

6. The dryer according to any one of claims 1 to 3, wherein, If the first temperature exceeds the first threshold, the control unit controls the flow adjustment unit in a manner that increases the flow rate of refrigerant flowing into the expansion mechanism. After controlling the flow adjustment unit, if the first temperature exceeds the first threshold, the control unit reduces the speed of the compressor.

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