JP2017196132A - Dryer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dryer, which enables a compressor to be operated at high frequency from start of drying operation while suppressing decrease in drying performance due to frost formation on an evaporator and prevents drying time from extending.SOLUTION: A dryer comprises: a heat pump 36; an evaporator temperature sensor 43, which detects the temperature of an evaporator 34; and a control device 50, which controls the heat pump 36 and a cycling air blower 26. The control device 50 drives a compressor 38 to operate at lower frequency than an initial frequency when a temperature Te detected by the evaporator temperature sensor 43 reaches a predetermined threshold temperature Tth1 or lower after the heat pump 36 is actuated by operating the compressor 38 at the initial frequency.SELECTED DRAWING: Figure 5

Description

  The present embodiment relates to a dryer.

  2. Description of the Related Art Conventionally, a dryer equipped with a heat pump has attracted attention as a dryer for drying clothes such as laundry because the clothes have less wrinkles and shrinkage, save energy, and have a shorter drying time.

  In a clothes dryer equipped with a heat pump, a circulation air passage communicating with a drying chamber containing clothes is provided, and a blower for circulating the air in the drying chamber through the circulation air passage and the evaporation of the heat pump are provided in the circulation air passage. A condenser and a condenser are provided.

  The heat pump includes a compressor that compresses and discharges the refrigerant, a condenser that dissipates and liquefies the high-temperature and high-pressure gas refrigerant discharged from the compressor, a decompression device that decompresses the refrigerant that has passed through the condenser, An evaporator that vaporizes the liquefied refrigerant is sequentially connected by piping, and the refrigerant is circulated by driving the compressor.

  Then, the air in the circulation air passage heated by the heat released from the condenser is sent into the drying chamber, and the air deprived of moisture from the clothing is dehumidified by cooling in the evaporator in the circulation air passage. The clothes are dried by repeatedly heating the air again with a condenser and supplying the air to the drying chamber.

  In the clothes dryer as described above, when the temperature of the installation atmosphere is low as in winter, the temperature of the evaporator flows due to the heat of vaporization of the refrigerant because the temperature of the air flowing in the circulation air channel is low immediately after the start of the heat pump operation. So-called frost formation may occur in which the water condensed at 0 ° C. or lower freezes. When frosting occurs in the evaporator, the frost becomes resistance of the air passing through the evaporator, the air volume flowing through the circulation air passage is reduced, the drying performance is reduced, and the air heated by the condenser is sufficient for the evaporator. In some cases, the frosting of the evaporator proceeds and the drying performance is further deteriorated.

  On the other hand, in Patent Document 1 below, when the detection result of the outside air temperature sensor is equal to or lower than a predetermined first threshold at the start of a drying operation in which the compressor is operated from a stopped state, the operating frequency of the compressor Starting with an initial value that is sufficiently lower than the maximum frequency, and gradually increasing the operating frequency of the compressor from the initial value so that the evaporator temperature does not fall below the second threshold for frosting. Therefore, it has been proposed to prevent frost formation on the evaporator and prevent a decrease in drying performance.

JP 2010-104579 A

  However, in the control in which the operation frequency of the compressor is started at a frequency sufficiently lower than the maximum frequency at the start of the drying operation, and then the operation frequency of the compressor is gradually increased, the compressor operates at a high frequency. It takes time to drive, and the drying time tends to be long. In particular, heat pumps in recent years have become less susceptible to frosting on the evaporator and lowering of the flow rate of the circulating air passage as the size of the evaporator increases and the performance of the blower increases. May not be able to effectively utilize the drying capacity.

  Accordingly, it is an object to provide a dryer that can operate the compressor at a high frequency from the start of the drying operation while preventing a decrease in drying performance due to frosting of the evaporator, and that does not easily increase the drying time. .

  The dryer according to the present embodiment includes a drying chamber in which clothes are accommodated, a circulation air passage that is provided outside the drying chamber, takes out air from the drying chamber, and returns the air to the drying chamber, and the drying chamber passes through the circulation air passage. A circulation fan that circulates air, a condenser that heats the air in the circulation air path, an evaporator that cools and dehumidifies the air in the circulation air path, and compresses the refrigerant to be supplied to the condenser A heat pump comprising a compressor, a capillary tube for depressurizing the refrigerant that has passed through the condenser, an evaporator temperature sensor that detects the temperature of the evaporator, and a control device that controls the heat pump and the circulation fan. The controller is configured to operate the compressor at an initial frequency and start a heat pump, and then when the temperature detected by the evaporator temperature sensor falls below a predetermined threshold temperature, There are those which operate the compressor at a frequency.

It is a figure which shows schematic structure of the washing-drying machine by one Embodiment. It is a perspective view from the back which shows the state except the outer case of the washing dryer. It is a figure which shows schematic structure of a heat pump. It is a block diagram which shows the electric constitution of a washing / drying machine. It is a flowchart of the drying process of a washing dryer.

  A washing dryer according to an embodiment will be described with reference to the drawings. In FIG. 1, a water tank 2 is disposed inside an outer box 1, and a drum 3 that is a rotating tank is disposed inside the water tank 2. Both the water tank 2 and the drum 3 have a cylindrical shape with one end closed. In this case, the water tank 2 and the drum 3 constitute a tank used for washing clothes (detergent washing and rinsing), dehydration and drying. And the inside of the drum 3 comprises the drying chamber 3a in which clothing is accommodated.

  The water tank 2 and the drum 3 have respective openings 4 and 5 at the front end face (left side in FIG. 1). Among these, the opening 5 of the drum 3 is where clothes are put in and out, and the opening 5 is surrounded by the opening 4 of the water tank 2. The opening 4 is connected via a bellows 7 to an opening 6 for putting in and taking out clothes formed on the front surface of the outer box 1. A door 8 is provided at the opening 6 of the outer box 1 so as to be openable and closable.

  In the drum 3, for example, a liquid-sealed rotary balancer is provided around the opening 5, and a hole 10 is formed in the circumferential side portion, that is, almost the entire region of the drum portion of the drum 3. The hole 10 functions as a water passage hole during washing and dehydration, and functions as a ventilation hole during drying. A plurality of baffles are provided on the inner surface of the peripheral side portion of the drum 3 so as to protrude inward of the drum 3. A plurality of hot air inlets 12 are formed in the end surface portion on the rear side of the drum 3.

  In the water tank 2, a hot air outlet 13 is formed in the upper part on the front side, and a hot air inlet 14 is formed in the upper part of the end surface part on the rear side. A drain port 15 is provided at the bottom of the water tank 2. A drain valve 16 is connected to the drain port 15 outside the water tank 2, and further, a drain hose 17 is connected to the drain valve 16 so that water in the water tank 2 can be discharged out of the machine.

  A washing machine motor 18 is attached to the rear surface of the aquarium 2, and a rotating shaft 19 that protrudes forward from the washing machine motor 18 passes through the rear end surface of the water tank 2, and the rear end surface of the drum 3. It is attached to the center of the part. Thereby, the drum 3 is coaxially supported by the water tank 2 so that rotation is possible.

  The water tank 2 is elastically supported by the outer box 1 via a plurality of suspensions 20 (see FIG. 2). The support form has an upwardly inclined shape in which the axial direction of the water tank 2 is located upward as it goes forward. Furthermore, the drum 3 is also arranged in the same form inside the water tank 2. In this case, the washing machine motor 18 is constituted by an outer rotor type brushless DC motor, and functions as a driving means for rotating the drum 3.

  A base plate 21 is disposed below the water tank 2 and on the bottom surface of the outer box 1, and a ventilation duct 22 is disposed on the base plate 21. The ventilation duct 22 has an air inlet 23 at the top of the front end. A hot air outlet 13 of the water tank 2 is connected to the air inlet 23 via a return air duct 24.

  A casing 27 of a circulation fan 26 is connected to the rear end portion of the ventilation duct 22. The outlet portion 28 of the casing 27 is connected to the hot air inlet 14 of the water tank 2 via the air supply duct 30. The air supply duct 30 is piped so as to bypass the left side of the washing machine motor 18. Here, the return air duct 24, the ventilation duct 22, the casing 27 of the circulation fan 26, and the air supply duct 30 connect the hot air outlet 13 and the hot air inlet 14 of the water tank 2, thereby forming a circulation air passage 31. Has been.

  As described above, the circulation air passage 31 has the end of the return air duct 24 connected to the hot air outlet 13 of the water tank 2 and the end of the air supply duct 30 connected to the hot air inlet 14. The inside of the drum 3 communicates with the inside of the drum 3 through a hole 10 provided in the drum 3.

  In the present embodiment, the circulation fan 26 is constituted by, for example, a centrifugal fan, and has a centrifugal impeller 32 inside the casing 27 and a fan motor 33 that rotates the centrifugal impeller 32 outside the casing 27. Yes. The fan motor 33 that rotates the centrifugal impeller 32 is configured such that the rotation speed can be changed by the control of the control device 50. By the operation of the circulation fan 26, an air flow as shown by an arrow A is generated in the circulation air passage 31 and the drying chamber 3a, and the air in the drying chamber 3a is taken out from the hot air outlet 13 and dried from the hot air inlet 14. A circulating air flow returning to 3a is formed.

  An evaporator 34 is disposed on the air outlet side (hot air outlet 13 side) of the drying chamber 3 a inside the ventilation duct 22 constituting the circulation air passage 31, and the circulation air flow is downstream of the evaporator 34. A condenser 35 is arranged on the side. These evaporator 34 and condenser 35 are tube-shaped with fins in which a large number of heat transfer fins are arranged at a fine pitch on the refrigerant flow pipe, and have excellent heat exchange properties. The above-described circulating air flow (circulating wind) in the ventilation duct 22 passes through each portion.

  A heat pump 36 that constitutes a drying means together with the circulation air passage 31 and the circulation blower 26 includes a refrigeration cycle 37 as shown in FIG. The refrigeration cycle 37 is configured by connecting a compressor 38, a condenser 35, a capillary tube 39, an evaporator 34, and an accumulator 40 in a closed loop shape and enclosing a refrigerant therein.

  The compressor 38 is disposed outside the circulation air passage 31 and has a discharge port for discharging the refrigerant and a suction port for sucking the refrigerant. The compressor 38 is a variable capacity compressor that can change the amount of refrigerant discharged by controlling the motor operating frequency by the control device 50. A condenser 35 is connected to the discharge port of the compressor 38, and high-temperature and high-pressure gaseous refrigerant is discharged to the condenser 35. The condenser 35 receives the gaseous refrigerant discharged from the compressor 38 and converts it into a heat radiation liquid, and then introduces the liquefied refrigerant into the capillary tube 39. The capillary tube 39 is composed of a pipe made of metal such as steel having a smaller inner diameter and outer diameter than the refrigerant distribution pipes of the condenser 35 and the evaporator 34 so that the refrigerant flowing from the condenser 35 can be easily vaporized. The pressure is reduced and then introduced into the evaporator 34.

  The evaporator 34 cools and dehumidifies the air in the ventilation duct 22 by vaporizing the liquid refrigerant decompressed in the capillary tube 39 and removing heat from the surroundings. The refrigerant that has evaporated and vaporized in the evaporator 34 flows into the accumulator 40 and is separated into a liquid refrigerant and a gaseous refrigerant, and only the gaseous refrigerant returns to the compressor 38 and is compressed again to form a high-temperature and high-pressure gaseous gaseous refrigerant. Become.

  As shown in FIGS. 3 and 4, the washing and drying machine includes an inlet temperature sensor 41, an outlet temperature sensor 42, an evaporator temperature sensor 43, and a condenser temperature sensor 44, and each temperature sensor 41, 42, 43, 44 is provided. It is connected to the control device 50.

  As shown in FIG. 3, the inlet temperature sensor 41 and the outlet temperature sensor 42 are provided in the circulation air passage 31 and detect the temperature of air in the circulation air passage 31. Among these, the inlet temperature sensor 41 is provided between the condenser 35 and the hot air inlet 14 and in the vicinity of the hot air inlet 14, and is supplied to the drying chamber 3a through the air supply duct 30, that is, The temperature of the air heated by the condenser 35 and supplied into the drying chamber 3a is detected. The outlet temperature sensor 42 is provided between the evaporator 34 and the hot air outlet 13 and in the vicinity of the hot air outlet 13, and detects the temperature of the air exhausted from the drying chamber 3 a and passing through the return air duct 24. .

  For example, the evaporator temperature sensor 43 is attached to the surface of the refrigerant circulation pipe or fin located on the windward side of the evaporator 34 (that is, the upstream side of the ventilation duct 22 in the airflow direction of the evaporator 34). Detect temperature. The condenser temperature sensor 44 is provided in the condenser 35 and detects the temperature of the condenser 35.

  The control device 50 includes, for example, a microcomputer and a memory, and is arranged inside the outer box 1 so as to function as control means for controlling the overall operation of the washing / drying machine.

  The control device 50 receives various operation signals from various operation switches provided in the operation display panel 45 provided on the upper portion of the front surface portion 1a of the outer box 1, and from each temperature sensor 41, 42, 43, 44. Temperature detection signals are input respectively. And the control apparatus 50 controls the drain valve 16, the washing machine motor 18, the fan motor 33, and the compressor 38 based on the input signal and the control program previously memorize | stored in memory.

  Next, an example of the operation of the washing / drying machine having the above configuration will be described.

  First, a schematic operation of the washing / drying machine will be described. The operation button on the operation display panel 45 is operated by the user to set the course of operation, and then the washing and drying machine continues the washing operation, the drying operation, or both of them according to the set operation course. The washing / drying operation to be performed is executed. As one of them, when the drying operation is executed, the heated air dehumidified by the ventilation duct 22 is rotated while rotating the drum 3 in which the wet clothes are stored in the drying chamber 3a in both forward and reverse directions at a low speed. The operation of supplying to 3a is performed.

  The operation of supplying the dehumidified heated air into the drying chamber 3a is performed by operating the heat pump 36 while driving the circulation fan 26. However, the control device 50 starts the operation of the compressor 38 and starts the heat pump. When starting 36, start control as shown in FIG. 5 is executed.

  Specifically, the control device 50 starts the operation of the circulation fan 26 by switching the fan motor 33 from the off state to the on state in step S <b> 1, and circulates the wind in the circulation air passage 31. Next, in step S2, the control device 50 sets the operating frequency f of the compressor 38 to the initial frequency f0, and drives the compressor 38 at the initial frequency f0. This initial frequency f0 is a compressor in which the frost adheres to the evaporator 34 so as not to interfere with the air flow in the circulation air passage 31 when the installation atmosphere of the washing / drying machine is low (for example, 5 ° C.). The upper limit value of 38 operating frequencies (for example, f0 = 90 Hz) is set.

  Then, the control device 50 determines whether or not a predetermined time (for example, 1 minute) has elapsed since the circulation fan 26 and the compressor 38 were driven in step S3. When the predetermined time has elapsed, the control device 50 proceeds to step S4. Based on the temperature detection signal from the temperature sensor 43, the windward evaporator temperature Te is detected.

  The control device 50 compares the detected evaporator temperature Te with the end determination temperature Tend. This end determination temperature Tend is set to a temperature (for example, Tend = 2 ° C.) at which frosting does not occur in the evaporator 34 after the heat pump 36 is started. When determining that the evaporator temperature Te is higher than the end determination temperature Tend (that is, Te> Tend) in step S5, the control device 50 proceeds to step S6, ends the start-up control, and starts normal operation.

  On the other hand, when it is determined in step S5 that the evaporator temperature Te is equal to or lower than the end determination temperature Tend (that is, Te ≦ Tend), the control device 50 proceeds to step S7 and compares the evaporator temperature Te with the first threshold temperature Tth1. To do. The first threshold temperature Tth1 is set to a temperature (for example, Tth2 = −2 ° C.) that causes frost formation in the evaporator 34 but does not hinder the air flow in the circulation air passage 31.

  When determining that the evaporator temperature Te is higher than the first threshold temperature Tth1 in Step S7 (that is, Tth1 <Te ≦ Tend), the control device 50 returns to Step S4 and detects the evaporator temperature Te.

  When determining that the evaporator temperature Te is equal to or lower than the first threshold temperature Tth1 (that is, Te ≦ Tth1) in step S7, the control device 50 proceeds to step S9 and compares the evaporator temperature Te with the second threshold temperature Tth2. The second threshold temperature Tth2 is set to a temperature at which the air heated by the condenser 35 is not sufficiently supplied to the evaporator 34 and frosting of the evaporator 34 proceeds (for example, Tth2 = −10 ° C.).

  When determining in step S9 that the evaporator temperature Te is equal to or lower than the second threshold temperature Tth2 (that is, Te ≦ Tth2), the control device 50 proceeds to step S12, stops the compressor 38, and after a predetermined time has elapsed (for example, After 5 minutes), the process returns to step S1 and the heat pump 36 is restarted.

  On the other hand, when determining that the evaporator temperature Te is higher than the second threshold temperature Tth2 in Step S9 (that is, Tth2 <Te ≦ Tth1), the control device 50 proceeds to Step S10, and the operating frequency f of the compressor 38 is the lower limit. It is determined whether the frequency is greater than fmin (for example, fmin = 40 Hz).

  If the control device 50 determines in step S10 that the operating frequency f of the compressor 38 is greater than the lower limit frequency fmin, the control device 50 proceeds to step S11 and sets the operating frequency f of the compressor 38 by a predetermined amount Δf (for example, Δf = 5 Hz). Change to a lower frequency (f-Δf). Then, after reducing the operating frequency of the compressor 38, the control device 50 proceeds to step S8, and after a predetermined time has elapsed (for example, after 2 minutes), returns to step S4 to detect the evaporator temperature Te. That is, after the operating frequency f is lowered and the compressor 38 is operated for a predetermined time, the evaporator temperature Te is detected again (step S4), and the control device 50 shifts to the normal operation according to the detected temperature. The operation frequency of the compressor 38 is maintained and the operation is continued, the operation frequency of the compressor 38 is further decreased by a predetermined amount Δf, or the compressor 38 is stopped (steps S5 to S12).

  In the present embodiment as described above, after the compressor 38 is driven at the initial frequency f0 when the heat pump 36 is started up, if the windward evaporator temperature Te is higher than the first threshold temperature Tth1, the operating frequency of the compressor 38 is set. When the initial frequency f0 is maintained and the evaporator temperature Te on the windward side is equal to or lower than the first threshold temperature Tth1, the operating frequency of the compressor 38 is decreased by a predetermined amount Δf. That is, in this embodiment, when the drying operation is started at a high frequency and the windward-side evaporator temperature Te falls below the first threshold temperature Tth1 and the frosting may occur on the evaporator 34, the operation of the compressor 38 is performed. Since the frequency is set to an appropriate operating frequency by reducing the frequency, the compressor 38 can be operated at a high frequency from an early stage after the start of the drying operation while suppressing a decrease in drying performance due to frosting of the evaporator 34. The drying time will not be unnecessarily long.

  In the present embodiment, since a plurality of threshold temperatures for changing the operating frequency of the compressor 38 are set, the operating frequency of the compressor 38 is changed or compressed depending on the degree of frost formation on the evaporator 34. The machine 38 can be stopped.

In the above-described embodiment, two types of threshold temperatures for changing the operation frequency of the compressor 38 are set, but three or more types of threshold temperatures may be set.
For example, the third threshold temperature Tth3 is set between the first threshold temperature Tth1 and the second threshold temperature Tth2, and the windward evaporator temperature Te detected by the evaporator temperature sensor 43 is set for a predetermined time (for example, 5 minutes). ) When the temperature continuously falls below the third threshold temperature Tth3 (for example, −9 ° C.), the operating frequency may be decreased by a predetermined amount Δf. In such a case, the operation frequency of the compressor 38 can be more finely controlled according to the degree of frost formation of the evaporator 34, and the start-up control can be terminated early to shift to the normal operation.

  In the above-described embodiment, the compressor temperature Te is detected by the evaporator temperature sensor 43 when the evaporator temperature Te is equal to or lower than the first threshold temperature Tth1 and higher than the second threshold temperature Tth2 (Tth2 <Te ≦ Tthe1). 38, the evaporator temperature sensor 43 detects the evaporator temperature Te again after a predetermined time, and the detected temperature is equal to or lower than the first threshold temperature Tth1 and the second threshold temperature. When it is higher than Tth2, the operating frequency of the compressor 38 is decreased again by a predetermined amount Δf. For example, a threshold temperature of 1 or 2 or more is set between the first threshold temperature Tth1 and the second threshold temperature Tth2, After the evaporator temperature Te detected by the evaporator temperature sensor 43 reaches the first threshold temperature Tth1 or lower and the operating frequency of the compressor 38 is decreased by a predetermined amount Δf, the evaporator temperature sensor is set. Evaporator temperature Te detected by the sub 43 may reduce the operating frequency of the compressor 38 for each first threshold temperature Tth1 reaches a threshold temperature set between the second threshold temperature Tth2. In this case, the predetermined amount Δf that lowers the operating frequency of the compressor 38 may be increased as the evaporator temperature Te detected by the evaporator temperature sensor 43 becomes equal to or lower than the threshold temperature set to a lower temperature.

  In the above-described embodiment, the case where the startup control is executed until the evaporator temperature Te reaches the end determination temperature Tend regardless of the temperature of the installation atmosphere of the washing / drying machine has been described. An outside air temperature sensor that detects the temperature of the outside air temperature sensor is provided, and the start control is performed when the temperature detected by the outside air temperature sensor is equal to or lower than the predetermined temperature, and the normal operation is performed without executing the start control when the temperature is higher than the predetermined temperature. .

(Other embodiments)
As mentioned above, although embodiment of this invention was described, these embodiment was shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 1 ... Outer box, 2 ... Water tank, 3 ... Drum, 3a ... Drying chamber, 22 ... Ventilation duct, 24 ... Return air duct, 26 ... Circulation fan, 30 ... Air supply duct, 31 ... Circulation air path, 34 ... Evaporation 35 ... condenser, 36 ... heat pump, 37 ... refrigeration cycle, 38 ... compressor, 39 ... capillary tube, 43 ... evaporator temperature sensor, 44 ... condenser temperature sensor, 50 ... controller

Claims (3)

A drying room in which clothing is housed;
A circulation air passage that is provided outside the drying chamber and extracts the air in the drying chamber and returns it to the drying chamber;
A circulation fan for circulating the air in the drying chamber through the circulation air passage;
A condenser that heats the air in the circulation air passage, an evaporator that cools and dehumidifies the air in the circulation air passage, a compressor that compresses a refrigerant and supplies the refrigerant to the condenser, and a condenser. A heat pump having a capillary tube for decompressing the refrigerant,
An evaporator temperature sensor for detecting the temperature of the evaporator;
A control device for controlling the heat pump and the circulation fan,
The control device operates the compressor at an initial frequency and starts a heat pump, and then when the temperature detected by the evaporator temperature sensor falls below a predetermined threshold temperature, the compressor operates at a frequency lower than the initial frequency. To drive the dryer.   The control device reduces the operating frequency of the compressor every time the threshold temperature is set in plural and the temperature detected by the evaporator temperature sensor is equal to or lower than the threshold temperature, and operates the compressor at a lower frequency. The dryer according to claim 1, wherein the compressor is stopped or the compressor is stopped.   3. The control device according to claim 2, wherein the control device stops the compressor when a temperature detected by the evaporator temperature sensor becomes equal to or lower than a threshold temperature set to a lowest temperature among the set threshold temperatures. Dryer.

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