Hand Drying Device

Abstract

Provided is a hand dryer comprising a housing having a hand insertion part, a nozzle that sprays a stream of air into the hand insertion part, a blower that generates the stream of air, a heater (23) which is connected to an AC power supply and which heats the stream of air, a hand detector that detects the hand inserted into the hand insertion part, and a controller (30) that controls the blower and the heater (23) on the basis of a detection signal from the hand detector indicating that the hand is detected. The controller (30) includes a voltage estimation circuit that estimates the voltage value of the AC power supply (40) and a control circuit that controls a current supply to the heater (23) according to the voltage value.

Description

[Technical field]

[0001] The present disclosure relates to a hand drying device that dries wet hands by blowing an air current onto the hands. [Background technology]

[0002] In order to maintain the hygienic condition of hands, it is necessary to hygienically dry hands after washing. For hygienic drying of hands after washing, instead of wiping wet hands after washing with a towel or handkerchief, a hand dryer is used that sprays a high-velocity air stream onto the hands to blow off water adhering to the hands and dry them.

[0003] When a hand is detected in the hand insertion section of the hand dryer, the hand dryer starts the air blower to draw air in through the suction port, heats the air drawn in through the suction port with a heater, and sprays the heated air from a nozzle provided in the hand insertion section. In this case, the use of hot air, which is the flow of air heated by the heater, makes it possible to dry the hands more quickly than when using low-temperature air.

[0004] An AC power supply is used as the power source for the heater in a hand dryer. There are 100V AC power supplies that supply AC voltages between 100V and 120V, and 200V AC power supplies that supply AC voltages between 200V and 240V. Conventionally, hand dryers use heaters with different specifications depending on the power supply voltage. That is, hand dryers used with 100V AC power supplies are equipped with 100V heaters, and hand dryers used with 200V AC power supplies are equipped with 200V heaters. Providing products with different specifications to match the voltage value of the AC power supply in this way has led to an increase in the number of models and increased costs.

[0005] Patent Document 1 discloses a method of standardizing a motor regardless of the power supply voltage. Patent Document 1 discloses a power supply device configured to detect the voltage value of an AC voltage, switch between voltage doubler rectification and full-wave rectification according to the voltage value, generate a DC voltage of the same voltage value, and supply it to a load. This makes it possible to mount a DC load, i.e., a motor, of the same specifications even in products used with AC power supplies of different voltage values. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6297999 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technology described in Patent Document 1 standardizes loads used with DC, but cannot standardize loads used with AC. In other words, the technology described in Patent Document 1 cannot be applied to standardizing heaters in hand dryers. As described above, in hand dryers, heaters to which AC voltage is applied must have different specifications for each type of power supply voltage, making it difficult to standardize heaters regardless of model. As a result, there is a problem that the number of models of hand dryers and the cost increase.

[0008] The present disclosure has been made in consideration of the above, and aims to obtain a hand dryer that can share a heater between products with different types of power supply voltages, without using heaters with different specifications for each type of power supply voltage. [Means for solving the problem]

[0009] In order to solve the above problems and achieve the object, the hand dryer disclosed herein includes a housing having a hand insertion section, a nozzle for spraying an airflow onto the hand insertion section, a blower for generating an airflow, a heater connected to an AC power source and for heating the airflow, a hand detection section for detecting a hand inserted into the hand insertion section, and a controller for controlling the blower and the heater based on a detection signal from the hand detection section indicating that a hand has been detected. The controller has a voltage estimation circuit for estimating a voltage value of the AC power source, and a control circuit for controlling energization to the heater in accordance with the voltage value. When the estimated voltage value is greater than a predetermined reference value, the control circuit reduces a heater energization rate, which is a rate of a period during which the heater is energized in a predetermined period, compared to when the estimated voltage value is less than the reference value, and controls the heater energization rate by phase control. do. Effect of the Invention

[0010] The hand dryer according to the present disclosure has the advantage that the heater can be shared among products having different types of power supply voltages, without using heaters with different specifications for each type of power supply voltage. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a hand dryer according to a first embodiment; [Diagram 2] Cross-sectional view of a hand dryer according to embodiment 1. [Diagram 3] FIG. 1 is a diagram showing an example of a schematic configuration of a circuit of a control unit of a hand dryer according to a first embodiment; [Figure 4] Diagram for explaining the operating principle of phase control [Diagram 5] A flowchart showing an example of a procedure of a control method for a hand dryer according to the first embodiment. [Figure 6] FIG. 13 is a diagram showing an example of heater control setting information. [Figure 7] FIG. 13 is a diagram showing an example of the relationship between the power-on time of a heater and the temperature in a hand dryer according to a second embodiment. [Figure 8] FIG. 13 is a diagram showing an example of a relationship between power supply time and power consumption in a hand dryer according to a second embodiment. [Figure 9] FIG. 13 is a diagram showing an example of a relationship between power supply time and power consumption in a hand dryer according to a third embodiment. [Figure 10]FIG. 13 is a diagram showing an example of the relationship between the power supply time of a heater and the temperature in a hand dryer according to a fourth embodiment. [Figure 11] 11 is a flowchart showing an example of a procedure of a heater output control method according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hand dryer according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0013] Embodiment 1 Fig. 1 is a perspective view of a hand dryer according to embodiment 1. Fig. 2 is a cross-sectional view of the hand dryer according to embodiment 1, taken along line II-II in Fig. 1.

[0014] Hand dryer 1 includes a housing 3 having a hand insertion section 2 into which hands can be inserted. The top and both sides of hand insertion section 2 are open. Hands can be inserted into hand insertion section 2 from the top and both sides. Housing 3 forms the entire outer shell of hand dryer 1. Front section 4 is part of housing 3 and is a portion on the front side of hand insertion section 2. Rear section 5 is part of housing 3 and is a portion on the rear side of hand insertion section 2. The front side is the side on which a user who uses hand dryer 1 is located, as viewed from hand dryer 1. The rear side is the side opposite to the front side, as viewed from hand dryer 1.

[0015] The water receiving section 6 is located at the bottom of the hand insertion section 2. The water receiving section 6 is provided with a drain outlet (not shown) that discharges received water into the drain tank 7. The housing 3 is also provided with a drainage channel (not shown) through which water from the drain outlet flows into the drain tank 7. The drain tank 7 stores the water from the drainage channel. The drain tank 7 is provided on the front side of the lower part of the housing 3. The drain tank 7 is removable from the housing 3.

[0016] The hand dryer 1 includes a blower 10 that generates an air flow inside a housing 3. The blower 10 is provided inside the housing 3. The blower 10 includes a motor 21, such as a DC (Direct Current) brushless motor, serving as a drive source, and a turbo fan 22 that rotates when driven by the motor 21. One example of the blower 10 is a high-pressure air flow generator.

[0017] The hand dryer 1 has a front nozzle 11 and a rear nozzle 12 that spray an airflow toward the hand insertion section 2. The front nozzle 11 and the rear nozzle 12 correspond to nozzles. The front nozzle 11 is provided on the surface of the front section 4 facing the hand insertion section 2. The rear nozzle 12 is provided on the surface of the rear section 5 facing the hand insertion section 2. The hand dryer 1 sprays the airflow that has passed from the blower 10 through a duct 13 inside the front section 4 from the front nozzle 11 at the hand insertion section 2. The hand dryer 1 sprays the airflow that has passed from the blower 10 through a duct 14 inside the rear section 5 from the rear nozzle 12 at the hand insertion section 2.

[0018] Hand dryer 1 includes hand detection unit 15 that detects a hand inserted into hand insertion unit 2. Hand detection unit 15 is built into back surface unit 5. One example of hand detection unit 15 is a distance measurement sensor. The distance measurement sensor includes a light-emitting element that emits infrared light and a light-receiving element that detects infrared light reflected by a hand, which is the object to be measured. Hand detection unit 15 detects the presence or absence of a hand in hand insertion unit 2 based on the angle of infrared light incident on the light-receiving element. Hand detection unit 15 may be any sensor other than a distance measurement sensor as long as it is capable of detecting a hand inserted into hand insertion unit 2. Hand detection unit 15 may be built into front surface unit 4.

[0019] The hand drying device 1 includes a heater 23 that heats the airflow sent to the ducts 13 and 14. The heater 23 is provided in an air passage between the blower 10 and the front nozzle 11 and the rear nozzle 12.

[0020] The housing 3 has an air intake 16 for drawing in air. The air intake 16 is provided in the lower part of the housing 3. The blower 10 takes in airflow from the air intake 16 into a duct 17 inside the housing 3, and sends the airflow from the duct 17 to the ducts 13 and 14. An air filter 18 is attached to the air intake 16 to remove foreign matter from the airflow taken into the duct 17.

[0021] A control unit 30 that controls the entire hand dryer 1 is provided inside the housing 3. Control unit 30 controls blower unit 10 and heater 23 based on a detection signal indicating that a hand has been detected from hand detection unit 15. Specifically, when a hand is detected by hand detection unit 15, control unit 30 energizes heater 23 and drives blower unit 10. When a hand is removed from hand insertion unit 2 and is no longer detected by hand detection unit 15, control unit 30 stops the operation of heater 23 and blower unit 10.

[0022] When a user inserts his or her hands into hand insertion section 2 of hand drying device 1 configured as described above, the high-pressure airflow generated by blower section 10 is heated by heater 23 and guided to front nozzle 11 provided on the front wall surface of hand insertion section 2 and rear nozzle 12 provided on the rear wall surface. High-speed airflow is then sprayed from front nozzle 11 and rear nozzle 12 into hand insertion section 2, blowing away moisture adhering to the hands inserted in hand insertion section 2. The blown-away moisture is then guided to drain tank 7 from a drain outlet provided in water receiving section 6 at the bottom of hand insertion section 2, and is stored in drain tank 7.

[0023] Fig. 3 is a diagram showing an example of a schematic configuration of a circuit of a control unit of the hand dryer according to the first embodiment. Note that Fig. 3 shows a schematic arrangement of each circuit, and does not show an actual circuit diagram. The control unit 30 includes a zero-cross detection circuit 31, a triac 32, a DC bus power supply 33, a voltage detection circuit 34, a power supply circuit 35, and a microcontroller circuit 36. Hereinafter, the microcontroller circuit 36 ​​will be referred to as a microcomputer circuit 36.

[0024] Zero-cross detection circuit 31 is a circuit that detects a zero-cross where the AC voltage of AC power supply 40 becomes zero. Triac 32 is an electronic component that drives heater 23. As shown in FIG. 3, heater 23 is connected in series with triac 32. Heater 23 is also connected to AC power supply 40. Here, the specifications, i.e., the type, of hand dryer 1 differ depending on the voltage of AC power supply 40, but heater 23 of the same type is used regardless of the voltage of AC power supply 40, i.e., regardless of the type of hand dryer 1.

[0025] The DC bus power supply 33 rectifies and smoothes the power supplied from the AC power supply 40 to generate a DC bus voltage. The DC bus power supply 33 generates a DC bus voltage corresponding to the effective value of the voltage of the AC power supply 40. The effective value of the voltage of the AC power supply 40 is also referred to as the voltage value of the AC power supply 40. The voltage detection circuit 34 detects the voltage value of the DC bus voltage. The voltage detection circuit 34 detects the voltage value of the DC bus voltage, and when the voltage value of the DC bus power supply 33 and the voltage value of the AC power supply 40 are associated with each other, the voltage value of the AC power supply 40 can be estimated from the voltage value of the DC bus voltage. The voltage detection circuit 34 may be any circuit that can detect or estimate the voltage value of the AC power supply 40. The voltage detection circuit 34 corresponds to a voltage estimation circuit. The power supply circuit 35 is a circuit that generates AC power for driving the motor 21 from the DC bus voltage. The motor 21 is connected to the power supply circuit 35. An example of the power supply circuit 35 is an inverter circuit.

[0026] The microcomputer circuit 36 ​​controls the power supply to the heater 23 according to the voltage value of the AC power supply 40. Specifically, the microcomputer circuit 36 ​​performs a heater control setting, which is a setting related to the power supply to the heater 23, according to the voltage value of the AC power supply 40. The heater control setting is executed, for example, when the power supply of the hand dryer 1 is turned on. Here, the microcomputer circuit 36 ​​sets the voltage detection value, which is the voltage of the DC bus power supply 33 detected by the voltage detection circuit 34, as the voltage value of the AC power supply 40 supplied to the hand dryer 1. The microcomputer circuit 36 ​​determines a power supply ratio, which is a ratio of a period of power supply to the heater 23 according to the magnitude of the voltage value of the AC power supply 40 in a determined period. This power supply ratio corresponds to a heater power supply ratio. The determined period can be one cycle of the voltage of the AC power supply 40. The timing of an ON command to the gate of the triac 32 is set so as to achieve the determined power supply ratio. This power supply ratio, i.e., the setting of the timing of the ON command, becomes the heater control setting. When the detected or estimated voltage value is greater than a predetermined reference value, the microcomputer circuit 36 ​​reduces the energization rate compared to when the detected or estimated voltage value is less than the reference value.

[0027] Microcomputer circuit 36 ​​controls power supply circuit 35 connected to triac 32 and motor 21 based on information from hand detection unit 15, heater control settings, and information from zero-cross detection circuit 31. This controls the ejection of hot air to hand insertion section 2 while a hand is inserted in hand insertion section 2. Although not shown, microcomputer circuit 36 ​​is also electrically connected to hand detection section 15 shown in Fig. 1, and determines whether a hand is present or not in hand insertion section 2 based on information from hand detection unit 15. Microcomputer circuit 36 ​​corresponds to the control circuit.

[0028] The heater 23 and the triac 32 are connected between the AC power supply 40 and the DC bus power supply 33. The zero-cross detection circuit 31 is connected between the AC power supply 40 and the heater 23 and the triac 32. The voltage detection circuit 34 is connected to the output side of the DC bus power supply 33.

[0029] The microcomputer circuit 36 ​​generates an ON command or an OFF command based on the heater control setting and information from the zero-cross detection circuit 31, and outputs it to the gate (not shown) of the triac 32. The triac 32 is turned on or off based on the ON command or the OFF command from the microcomputer circuit 36. In this example, the heater 23 is configured to be driven by phase control. FIG. 4 is a diagram for explaining the operation principle of phase control. FIG. 4 shows an input voltage waveform VI, a gate input signal GI which is a signal input to the gate of the triac 32, and a voltage waveform VH applied to the heater 23. In these figures, the horizontal axis indicates time. Also, the vertical axis of the input voltage waveform VI and the voltage waveform VH applied to the heater 23 indicates voltage, and the vertical axis of the gate input signal GI indicates whether the signal is ON or OFF. Note that the timing for turning off the triac 32 is set to the case where the input voltage waveform VI becomes zero, and the current flowing through the triac 32 at this timing becomes zero. Therefore, the microcomputer circuit 36 ​​does not output an OFF command. That is, the gate input signal GI indicates the ON commands GI1, GI2, and GI3 output from the microcomputer circuit 36.

[0030] Phase control is a control method that varies the applied voltage by directly turning the AC voltage on or off using the triac 32, and adjusts the timing of the on-time and off-time based on the power supply zero-cross point to vary the voltage applied to the heater 23. The power supply zero-cross point is the point where the voltage becomes zero in the input voltage waveform VI.

[0031] Specifically, the microcomputer circuit 36 ​​outputs ON commands GI1, GI2, and GI3 to the triac 32 every half cycle of the input voltage waveform VI. In the example of Fig. 4, the microcomputer circuit 36 ​​outputs ON commands GI1, GI2, and GI3 at times t1, t3, and t5. When the microcomputer circuit 36 ​​outputs the ON command GI1 to the gate of the triac 32 at time t1, the triac 32 is turned on at time t1, and a current flows through the triac 32 and the heater 23. Thereafter, at time t2 when the input voltage becomes zero, the triac 32 is turned off, and no current flows through the heater 23. A voltage is applied to the heater 23 as shown by the voltage waveform VH applied to the heater 23 in Fig. 4. In other words, during the half cycle from time t0 to time t2 of the input voltage waveform VI, a voltage is applied to the heater 23 from time t1 to time t2, and no voltage is applied to the heater 23 from time t0 to time t1.

[0032] After that, when the microcomputer circuit 36 ​​outputs an ON command GI2 to the gate of the triac 32 at time t3, the triac 32 is turned ON at time t3, and a current flows through the triac 32 and the heater 23. The direction of the current flowing through the triac 32 and the heater 23 at this time is opposite to the direction of the current flowing between time t1 and t2. After that, at time t4 when the input voltage becomes zero, the triac 32 is turned OFF, and no current flows through the heater 23. A voltage is applied to the heater 23 as shown in the voltage waveform applied to the heater 23 in FIG. 4. That is, during the half cycle from time t2 to time t4 of the input voltage waveform VI, a voltage is applied to the heater 23 from time t3 to time t4, and no voltage is applied to the heater 23 from time t2 to time t3. This process is then repeated. By adjusting the output timing of the ON commands GI1, GI2, and GI3 to the gates, that is, the ON time, it is possible to change the voltage applied to the heater 23.

[0033] For example, if the microcomputer circuit 36 ​​outputs ON commands GI1, GI2, and GI3 to the gate of the triac 32 at times t0, t2, and t4 so that the triac 32 is turned on at the power supply zero cross point where the voltage becomes zero in the input voltage waveform VI, the conduction angle to the heater 23 is 100%. If the ON commands GI1, GI2, and GI3 are output to the gate of the triac 32 at a position 90 degrees ahead of the power supply zero cross point, assuming that one period of the input voltage waveform VI is 360 degrees, the conduction angle to the heater 23 is 50%. In other words, the conduction angle is the conduction rate, which is the ratio of the period during which the heater 23 is energized in one period, which is a set period. If the time during which the triac 32 is on in one period, i.e., the time during which the heater 23 is energized, is long, the power value becomes large, and if the ON time is short, the power value becomes small. The timing of turning on and off, i.e., the conduction angle, can be set arbitrarily by the microcomputer circuit 36.

[0034] In this way, the voltage applied to the heater 23 changes depending on the timing when the microcomputer circuit 36 ​​outputs the ON commands GI1, GI2, and GI3 to the gate of the triac 32, and the amount of heat generated by the heater 23 also changes. By adjusting the output timing of the ON commands GI1, GI2, and GI3 to the gate of the triac 32 according to the type of the AC power supply 40, the amount of heat generated by the heater 23 can be set to a predetermined amount regardless of the type of the AC power supply 40. For this purpose, the microcomputer circuit 36 ​​obtains the output voltage of the DC bus power supply 33 from the voltage detection circuit 34 and estimates the voltage value of the AC power supply 40 from the output voltage. The microcomputer circuit 36 ​​also obtains information from the zero-cross detection circuit 31. The information from the zero-cross detection circuit 31 includes, for example, the power supply zero-cross point, which is the time when the zero-cross detection circuit 31 detects a zero cross. The microcomputer circuit 36 ​​determines the output timing of the ON commands GI1, GI2, and GI3 to the gate of the triac 32 so that the conduction angle corresponds to the value of the output voltage based on the power supply zero-cross point.

[0035] Although an example has been shown here in which the proportion of electricity supplied to the heater 23 is controlled using phase control, the proportion of electricity supplied to the heater 23 may be controlled using power duty control.

[0036] Next, a control method by control unit 30 of hand dryer 1 according to embodiment 1 will be described. Fig. 5 is a flowchart showing an example of the procedure of the control method of the hand dryer according to embodiment 1. Here, it is assumed that the voltage value of AC power source 40 is either a 100V system AC power source that supplies an AC voltage between 100V and 200V, or a 200V system AC power source that supplies an AC voltage between 200V and 240V.

[0037] First, when the hand dryer 1 is powered on, the voltage detection circuit 34 detects the voltage of the DC bus power supply 33 and outputs the detection result, that is, a voltage detection value, to the microcomputer circuit 36 ​​(step S11). Since the voltage value of the DC bus power supply 33 changes depending on the voltage value of the AC power supply 40, it is possible to estimate the voltage value of the AC power supply 40 from the voltage detection value of the DC bus power supply 33.

[0038] When the microcomputer circuit 36 ​​receives the voltage detection value from the voltage detection circuit 34, it performs heater control setting (step S12). As described above, the heater control setting is the setting of the conduction angle, and the setting of the timing of outputting an ON command to the gate of the triac 32. In one example, the microcomputer circuit 36 ​​holds heater control setting information that associates the voltage detection value with the conduction angle, obtains the conduction angle corresponding to the voltage detection value from the heater control setting information, and performs setting based on the conduction angle.

[0039] FIG. 6 is a diagram showing an example of heater control setting information. In the heater control setting information, the voltage detection value of the DC bus power supply 33 is associated with the conduction angle. Here, the range of the voltage detection value is associated with the conduction angle. Specifically, when the voltage detection value of the DC bus power supply 33 is 150V or less, the conduction angle is set to 100%, and when the voltage detection value is greater than 150V, the conduction angle is set to 50%. When the voltage detection value is 150V or less, the AC power supply 40 is a 100V AC power supply, and when the voltage detection value is greater than 150V, the AC power supply 40 is a 200V AC power supply. In this way, the smaller the voltage value of the AC power supply 40, the larger the conduction angle, i.e., the current supply ratio, is set.

[0040] In addition, when the voltage detection value of the DC bus power supply 33 is 150V, the conduction angle is set to 100% in FIG. 6, but the conduction angle may be set to 50%. Furthermore, 150V in the heater control setting information is a value that is a reference value for dividing the conduction angle settings, and corresponds to a reference value. The reference value here is 150V, but this is only an example and other values ​​may be used. Furthermore, the conduction angle in FIG. 6 is only an example and may be any value. However, the conduction angle is set to be larger as the voltage value of the AC power supply 40 is lower.

[0041] If the voltage detection value is 150V or less, the microcomputer circuit 36 ​​determines that the model is compatible with a 100V AC power supply, i.e., that the device is connected to a 100V AC power supply, and sets the conduction angle to 100% by referring to the heater control setting information. Also, if the voltage detection value is greater than 150V, the microcomputer circuit 36 ​​determines that the model is compatible with a 200V AC power supply, i.e., that the device is connected to a 200V AC power supply, and sets the conduction angle to 50% by referring to the heater control setting information.

[0042] Returning to FIG. 5, the microcomputer circuit 36 ​​judges whether a hand has been detected by the hand detection unit 15 (step S13). If a hand has not been detected (No in step S13), the microcomputer circuit 36 ​​enters a waiting state. If a hand has been detected (Yes in step S13), that is, if the user's hand has been inserted into the hand insertion unit 2, the microcomputer circuit 36 ​​starts driving the heater according to the heater control settings set in step S12 (step S14). That is, the microcomputer circuit 36 ​​starts controlling the supply of electricity to the heater 23. Specifically, when the microcomputer circuit 36 ​​receives information indicating that a power supply zero cross point has been detected from the zero cross detection circuit 31, the microcomputer circuit 36 ​​outputs an ON command to the gate of the triac 32 after a time corresponding to the conduction angle has elapsed since receiving the detection signal. When the ON command is input to the gate of the triac 32, the triac 32 enters a conducting state, and a voltage is applied to the heater 23. Thereafter, when the input voltage from the AC power supply 40 becomes zero, the current flowing through the triac 32 becomes zero, and the voltage applied to the heater 23 becomes zero. At this time, the zero-cross detection circuit 31 detects the power supply zero-cross point and notifies the microcomputer circuit 36 ​​of a detection signal. In this manner, the process of applying voltage to the heater 23 is repeatedly executed from when the ON command is received until the input voltage becomes zero.

[0043] Microcomputer circuit 36 ​​also starts driving the motor (step S15). Here, microcomputer circuit 36 ​​controls the conduction angle to motor 21 to be a determined value. As a result, the high-pressure airflow generated by blower unit 10 and heated by heater 23 is sprayed toward the hands from front nozzle 11 and back nozzle 12 of hand insertion section 2 as a high-speed airflow.

[0044] Thereafter, microcomputer circuit 36 ​​determines whether or not a hand is no longer detected by hand detection unit 15 (step S16). If a hand is detected (No in step S16), the state of spraying the heated high-speed airflow toward the hand continues. If a hand is no longer detected (Yes in step S16), that is, if the hand is removed from hand insertion unit 2, microcomputer circuit 36 ​​stops driving the heater (step S17), and microcomputer circuit 36 ​​stops driving the motor (step S18). Then, the process returns to step S13.

[0045] As described above, the first embodiment includes zero-cross detection circuit 31 that detects a power supply zero-cross point in AC power supply 40, voltage detection circuit 34 that detects a voltage value of DC bus power supply 33 that converts AC power supply 40 into a DC power supply, triac 32 connected in series to heater 23, and microcomputer circuit 36 ​​that controls a voltage applied to heater 23 according to a voltage detection value in voltage detection circuit 34. Microcomputer circuit 36 ​​sets a conduction angle to heater 23 according to the magnitude of the voltage detection value. When the voltage detection value is large, the conduction angle is set so that the conduction angle is smaller than when the voltage detection value is small. Microcomputer circuit 36 ​​drives heater 23 when a hand is inserted into hand insertion section 2. At this time, when microcomputer circuit 36 ​​receives information indicating that a zero cross has been detected from zero-cross detection circuit 31, it outputs an ON command to triac 32 after a time corresponding to the set conduction angle has elapsed, and applies an AC voltage to heater 23. When the AC voltage becomes zero, the AC voltage applied to the heater 23 also becomes zero. In this manner, the AC voltage can be applied to the heater 23 during a period of the AC voltage cycle that corresponds to the set conduction angle. That is, the AC voltage can be applied to the heater 23 in accordance with the voltage value of the AC power supply 40 so that the air flow reaches the target temperature.

[0046] When the voltage detection value is low, for example, when the hand dryer 1 is a model compatible with a 100V AC power supply, that is, when the hand dryer 1 is connected to a 100V AC power supply, the conduction angle to the heater 23 is set to be large. When the voltage detection value is high, for example, when the hand dryer 1 is a model compatible with a 200V AC power supply, that is, when the hand dryer 1 is connected to a 200V AC power supply, the conduction angle to the heater 23 is set to be small. This makes it possible to maintain the heating performance of the common heater 23 at the same level even if the voltage value of the AC power supply 40 is different. In other words, the heater 23 can be made common between models of the hand dryer 1 according to the type of the AC power supply 40. As a result, there is an effect that the heater 23 can be made common between products having different power supply voltages of the AC power supply 40 without using heaters 23 with different specifications for each power supply voltage of the AC power supply 40.

[0047] In the above description of FIG. 5, an example was shown in which the heater control setting is changed for a model compatible with a 100V AC power source and a model compatible with a 200V AC power source. However, depending on the destination, there are some areas where three types of AC power sources 40 are provided: a 110V AC power source, a 120V AC power source, and an AC power source ranging from 220V to 240V. In this case, when setting the conduction angle, the case may be classified according to voltage. That is, in the heater control setting, the range of the voltage detection value and the conduction angle may be determined for each of the 110V AC power source, the 120V AC power source, and the AC power source ranging from 220V to 240V. This makes it possible to further subdivide the power source voltage and set the conduction angle to the heater 23.

[0048] Embodiment 2 In the first embodiment, once the conduction angle to the heater 23 is set in accordance with the voltage detection value detected by the voltage detection circuit 34, the conduction angle is kept constant when the heater 23 is subsequently driven. In the second embodiment, a case will be shown in which the conduction angle is changed when the heater 23 is driven.

[0049] The configuration of the hand dryer 1 according to the second embodiment is the same as that shown in the first embodiment, but the function of the microcomputer circuit 36 ​​in the control unit 30 is different from that of the first embodiment. The following describes the differences from the first embodiment. In the second embodiment, the microcomputer circuit 36 ​​sets the conduction angle, which is the ratio of current supply to the heater 23 set with respect to the magnitude of the voltage value of the AC power source 40, as a target conduction angle, starts current supply to the heater 23 at a conduction angle larger than the target conduction angle, and changes the conduction angle to the target conduction angle after a specified time has elapsed. That is, the conduction angle in the heater control setting information becomes the target set value. Then, the microcomputer circuit 36 ​​makes the conduction angle larger than the target set value when the heater 23 starts to be driven, and gradually decreases it to the target set value. The timing and time for changing the conduction angle can be set arbitrarily.

[0050] FIG. 7 is a diagram showing an example of the relationship between the power-on time and the temperature of the heater in the hand dryer according to the second embodiment. In this diagram, the horizontal axis indicates the power-on time of the heater 23, and the vertical axis indicates the temperature of the heater 23. Graph G1 shown by a solid line shows the relationship between the power-on time and the temperature until the target temperature is reached when the conduction angle is set to 50% in a model compatible with a 200V AC power source in the first embodiment. Graph G2 shown by a dashed line shows the relationship between the power-on time and the temperature until the target temperature is reached when the conduction angle is gradually reduced to the target set value in a model compatible with a 200V AC power source. In the graph G2, the target set value of the conduction angle is 50%, but the conduction angle is changed from 100% to 90% to 80% to 50%.

[0051] In the case of graph G2, when the microcomputer circuit 36 ​​starts driving the heater, the conduction angle is set to 100%, so when it receives information from the zero-cross detection circuit 31 indicating that a zero cross has been detected, it outputs an ON command to the gate of the triac 32. After issuing this ON command a specified number of times or for a specified period of time, the microcomputer circuit 36 ​​sets the conduction angle to 90%. After receiving information from the zero-cross detection circuit 31 indicating that a zero cross has been detected, the microcomputer circuit 36 ​​outputs an ON command to the gate of the triac 32 a period of time corresponding to a conduction angle of 90%. After issuing this ON command a specified number of times or for a specified period of time, the microcomputer circuit 36 ​​reduces the conduction angle by 10 points at a time until the conduction angle reaches 50%, and performs the same process.

[0052] As shown in graph G1, if the conduction angle is controlled to be constant without being changed, the temperature of the heater 23 gradually rises with the passage of current and reaches the target temperature. In contrast, as shown in graph G2, by setting the conduction angle larger than the target setting value at the start of current passage and gradually decreasing it until it reaches the target setting value, the temperature rises rapidly at the start of current passage. This makes it possible to quickly reach the target temperature.

[0053] In the second embodiment, when the microcomputer circuit 36 ​​starts energizing the heater 23, it gradually decreases the conduction angle from a large value to the target set value. This makes it possible to shorten the time to reach the target temperature when the conduction angle is lower than 100% and the target set value is reached, compared to when the conduction angle is set to the target set value and energization to the heater 23 is started. That is, in the first embodiment, it takes time for the heater 23 to warm up, but in the method of the second embodiment, the temperature of the heater 23 can reach the target temperature more quickly than in the first embodiment. This makes it possible to dry the user's hands faster.

[0054] In the above description, the conduction angle is gradually reduced to the target set value. The number of steps for reducing the conduction angle may be one or more. In one example, the conduction angle may be changed to the target set value after energizing the heater 23 for a specified period of time at a conduction angle larger than the target set value.

[0055] Furthermore, the above example is effective when heater 23 for a model compatible with a 100V AC power source is used in hand dryer 1 and a 200V AC power source is applied to heater 23. However, by selecting heater 23 with a higher heat generation, it is possible to expect the effect of shortening the heating time even when a 100V AC power source is applied.

[0056] Embodiment 3 In the first embodiment, the microcomputer circuit 36 ​​drives the motor 21 so that the conduction angle to the motor 21 is a fixed value. In the third embodiment, the microcomputer circuit 36 ​​changes the conduction angle to the motor 21 together with the heater 23.

[0057] The configuration of hand dryer 1 according to embodiment 3 is similar to that shown in embodiments 1 and 2, but the function of microcomputer circuit 36 ​​in control unit 30 is different from that of embodiments 1 and 2. The following describes the differences from embodiments 1 and 2. The following description will be given assuming that hand dryer 1 has the configuration of embodiment 2.

[0058] In the third embodiment, the microcomputer circuit 36 ​​gradually increases the conduction angle to the motor 21, which is the ratio of the period during which current is supplied to the motor 21 in a set period, in response to a change in the conduction angle, which is the ratio of current supplied to the heater 23. The conduction angle to the motor 21 corresponds to the motor current supply ratio. In other words, the microcomputer circuit 36 ​​gradually increases the conduction angle to the motor 21 in response to gradually decreasing the conduction angle to the heater 23 toward the target set value.

[0059] FIG. 8 is a diagram showing an example of the relationship between the energization time and the power consumption in the hand dryer according to the second embodiment. In this diagram, the horizontal axis indicates the energization time, and the vertical axis indicates the power consumption. Graph G11 shown by a solid line indicates the power consumption when the motor 21 is driven with a constant conduction angle, and graph G12 shown by a dashed line indicates the power consumption when the conduction angle to the heater 23 is gradually reduced. Graph G13 shown by a dashed line indicates the power consumption of the entire load, which is a combination of the power consumption of the motor 21 and the power consumption of the heater 23. As shown in graph G12, immediately after energization of the heater 23, the conduction angle to the heater 23 is large, so the power consumed by the heater 23 is maximum during the energization time. As a result, the power consumption of the entire load, which is a combination of the power consumption of the motor 21 and the heater 23, is a large power value at the start of energization, as shown in graph G13.

[0060] FIG. 9 is a diagram showing an example of the relationship between the energization time and the power consumption in the hand dryer according to the third embodiment. In this diagram, the horizontal axis indicates the energization time, and the vertical axis indicates the power consumption. Graph G21 shown by a solid line indicates the power consumption when the conduction angle to the motor 21 is gradually increased, and graph G22 shown by a dashed line indicates the power consumption when the conduction angle to the heater 23 is gradually decreased. Graph G23 shown by a dashed line indicates the power consumption of the entire load, which is a combination of the power consumption of the motor 21 and the power consumption of the heater 23. As shown in the graph G22 in FIG. 9, the conduction angle to the heater 23 is large immediately after the energization of the heater 23, so that the power consumed by the heater 23 is maximum during the energization time. On the other hand, in the third embodiment, as shown in the graph G21, the conduction angle to the motor 21 is gradually increased as the conduction angle to the heater 23 gradually decreases. By controlling in this manner, as shown in the graph G23, the power consumption of the entire load can be always kept constant. Moreover, compared to the case of FIG. 8, power consumption can be suppressed, and energy saving can be improved.

[0061] In the third embodiment, when microcomputer circuit 36 ​​of hand dryer 1 starts supplying electricity to heater 23, the conduction angle to heater 23 is gradually decreased from a value larger than a target set value to the target set value, and the conduction angle to motor 21 is gradually increased from a value smaller than a determined value to the determined value. This makes it possible to keep the power consumption of the entire load constant while maintaining the time required for heater 23 to reach the target temperature similar to that of the second embodiment. As a result, it is possible to improve energy saving without compromising the feeling of warm air.

[0062] Furthermore, in the control shown in Fig. 8, a large inrush current flows at startup, i.e., when current begins to flow, which may cause the current fuse to blow prematurely or cause the electronic components of the power supply system to deteriorate, leading to early failure. However, in the control shown in Fig. 9 of the third embodiment, the inrush current at startup can be suppressed, thereby reducing the possibility of failure of the electronic components of the power supply system.

[0063] In the above description, the conduction angle to the motor 21 is controlled. However, the conduction angle to the motor 21 may be controlled using phase control, current duty control, inverter control, or the like.

[0064] Embodiment 4 In the first embodiment, once the conduction angle is set based on the voltage detection value detected by the voltage detection circuit 34, the conduction angle is kept constant when the heater 23 is subsequently driven. In the second embodiment, the conduction angle is gradually decreased so as to reach a target set value when the heater 23 is driven. In the fourth embodiment, a case will be shown in which the conduction angle to the heater 23 is increased when current is applied to the heater 23 for a period longer than a set period.

[0065] The configuration of hand dryer 1 according to embodiment 4 is similar to that shown in embodiments 1 to 3, but the function of microcomputer circuit 36 ​​in control unit 30 is different from that of embodiments 1 to 3. The following describes the differences from embodiments 1 to 3. The following describes hand dryer 1 as having the configuration of embodiment 2. In embodiment 4, microcomputer circuit 36 ​​measures time from the start of energization of heater 23, and increases the conduction angle to heater 23 when energization to heater 23 continues after a set time has elapsed.

[0066] The time it takes to dry hands after washing them may vary depending on the season or the way the hands are washed. In addition, there are individual differences in the perception of whether the hands are sufficiently dry depending on the user. If the hands are not sufficiently dried after a certain time has passed, or if the user feels that the hands are not sufficiently dried, the time of use of the hand dryer 1 will be extended. Therefore, if the hands are still not dried after a set time has passed, the microcomputer circuit 36 ​​determines that the drying is insufficient and further increases the temperature of the heater 23. In other words, the conduction angle to the heater 23 is increased above the target set value. This improves the user's sense of warm air and shortens the time required for drying.

[0067] FIG. 10 is a diagram showing an example of the relationship between the energization time and the temperature of the heater in the hand dryer according to the fourth embodiment. In this diagram, the horizontal axis indicates the energization time of the heater 23, and the vertical axis indicates the temperature of the heater 23. As described in the second embodiment, until the energization time of the heater 23 reaches 10 seconds, the conduction angle is gradually changed from 100% to the target set value of 50%. If the state in which the hand is inserted in the hand insertion section 2 continues even after 10 seconds have passed since the start of energization of the heater 23, that is, if the energization of the heater 23 continues, the microcomputer circuit 36 ​​increases the set value of the conduction angle to the heater 23. In the example of FIG. 10, the conduction angle to the heater 23 is changed from 50% to 75%. Note that, in FIG. 10, an example is shown in which the time for increasing the set value of the conduction angle is 10 seconds, but this is only an example and can be any time.

[0068] Next, a control method by the control unit 30 of the hand dryer 1 according to the embodiment 4 will be described. Fig. 11 is a flow chart showing an example of the procedure of the heater output control method according to the embodiment 4. Note that the same processes as those in Fig. 5 of the embodiment 1 are given the same step numbers and their description will be omitted.

[0069] In the fourth embodiment, when the microcomputer circuit 36 ​​starts driving the heater in step S14, the microcomputer circuit 36 ​​starts measuring time (step S31).

[0070] Also, if a hand is detected in step S16 (if No in step S16), it is determined whether a predetermined time has elapsed since the start of heater drive (step S32). If the predetermined time has not elapsed (if No in step S32), the process returns to step S16. If the predetermined time has elapsed (if Yes in step S32), the microcomputer circuit 36 ​​increases the conduction angle to the heater 23 from the current value (step S33). Thereafter, the microcomputer circuit 36 ​​determines whether a hand is no longer detected by the hand detection unit 15 (step S34). If a hand is detected (if No in step S34), the state of spraying the heated high-speed airflow toward the hand continues. If a hand is no longer detected (if Yes in step S34), the process proceeds to step S17.

[0071] By such processing, when the user inserts his / her hands for a specified time or longer, the conduction angle to the heater 23 is increased, and the temperature of the high-velocity airflow is increased compared to before the conduction angle to the heater 23 was increased, thereby improving the feeling of warm air for the user.

[0072] In the above description, the microcomputer circuit 36 ​​changes the set value to a predetermined conduction angle when the hand is inserted for a predetermined time or longer. However, the microcomputer circuit 36 ​​may control the conduction angle to the heater 23 to gradually increase to the predetermined conduction angle when the time that the heater 23 is energized has elapsed. This can improve the feeling of warm air without causing the user discomfort due to a sudden temperature change.

[0073] In the above description, the fourth embodiment is applied to the hand dryer 1 of the second embodiment. However, the fourth embodiment may be applied to the hand dryer 1 of the first and third embodiments.

[0074] In the fourth embodiment, the microcomputer circuit 36 ​​starts timing when the power supply to the heater 23 starts, and if the power supply to the heater 23 is continued for a set time or longer, the microcomputer circuit 36 ​​increases the conduction angle to the heater 23. This has the effect of improving the feeling of warm air when the hands are not sufficiently dried or when the user feels that the hands are not sufficiently dried.

[0075] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0076] 1 hand dryer, 2 hand insertion section, 3 housing, 4 front section, 5 rear section, 6 water receiving section, 7 drain tank, 10 air blower, 11 front nozzle, 12 rear nozzle, 13, 14, 17 duct, 15 hand detection section, 16 air intake port, 18 air filter, 21 motor, 22 turbo fan, 23 heater, 30 control section, 31 zero cross detection circuit, 32 triac, 33 DC bus power supply, 34 voltage detection circuit, 35 power supply circuit, 36 microcomputer circuit, 40 AC power supply.

Claims

1. A housing having a hand insertion portion, A nozzle that sprays an air flow to the hand insertion portion; A blower unit that generates the air flow; a heater connected to an AC power source for heating the airflow; a hand detection unit that detects a hand inserted into the hand insertion unit; a control unit that controls the blower unit and the heater based on a detection signal from the hand detection unit indicating that the hand has been detected; Equipped with The control unit is a voltage estimation circuit that estimates a voltage value of the AC power supply; a control circuit for controlling energization of the heater in response to the voltage value; having The hand dryer is characterized in that, when the estimated voltage value is greater than a predetermined reference value, the control circuit reduces a heater power supply rate, which is the ratio of a period during which power is supplied to the heater in a predetermined period, compared to when the estimated voltage value is smaller than the reference value, and controls the heater power supply rate by phase control.

2. A housing having a hand insertion portion; A nozzle that sprays an air flow to the hand insertion portion; A blower unit that generates the air flow; a heater connected to an AC power source for heating the airflow; a hand detection unit that detects a hand inserted into the hand insertion unit; a control unit that controls the blower unit and the heater based on a detection signal from the hand detection unit indicating that the hand has been detected; Equipped with The control unit is a voltage estimation circuit that estimates a voltage value of the AC power supply; a control circuit for controlling energization of the heater in response to the voltage value; having The hand dryer is characterized in that, when the estimated voltage value is greater than a predetermined reference value, the control circuit reduces a heater power supply rate, which is the ratio of the period during which power is supplied to the heater in a predetermined period, compared to when the estimated voltage value is smaller than the reference value, and controls the heater power supply rate by power supply rate control.

3. A housing having a hand insertion portion, A nozzle that sprays an air flow to the hand insertion portion; A blower unit that generates the air flow; a heater connected to an AC power source for heating the airflow; a hand detection unit that detects a hand inserted into the hand insertion unit; a control unit that controls the blower unit and the heater based on a detection signal from the hand detection unit indicating that the hand has been detected; Equipped with The control unit is a voltage estimation circuit that estimates a voltage value of the AC power supply; a control circuit for controlling energization of the heater in response to the voltage value; having the control circuit sets a heater power supply ratio, which is the ratio of a period during which power is supplied to the heater in a predetermined period that is set with respect to the magnitude of the voltage value of the AC power supply, as a target heater power supply ratio, starts power supply to the heater at a heater power supply ratio greater than the target heater power supply ratio, and changes the heater power supply ratio to the target heater power supply ratio after a predetermined time has elapsed.

4. 4. The hand dryer according to claim 3, wherein the control circuit gradually reduces the heater power supply rate from the start of power supply to the heater to the target heater power supply rate.

5. The blower unit includes a fan that generates the air flow by rotating, and a motor that rotates the fan, 5. The hand dryer according to claim 3, wherein the control circuit gradually increases a motor power supply rate, which is a rate of a period during which power is supplied to the motor in a set period, in response to the change in the heater power supply rate.

6. A housing having a hand insertion portion, A nozzle that sprays an air flow to the hand insertion portion; A blower unit that generates the air flow; a heater connected to an AC power source for heating the airflow; a hand detection unit that detects a hand inserted into the hand insertion unit; a control unit that controls the blower unit and the heater based on a detection signal from the hand detection unit indicating that the hand has been detected; Equipped with The control unit is a voltage estimation circuit that estimates a voltage value of the AC power supply; a control circuit for controlling energization of the heater in response to the voltage value; having The hand dryer is characterized in that the control circuit increases a heater power supply rate, which is the ratio of the period during which power is supplied to the heater to a predetermined period, when the time during which power is supplied to the heater has elapsed a predetermined time.

7. A housing having a hand insertion portion; A nozzle that sprays an air flow to the hand insertion portion; A blower unit that generates the air flow; a heater connected to an AC power source for heating the airflow; a hand detection unit that detects a hand inserted into the hand insertion unit; a control unit that controls the blower unit and the heater based on a detection signal from the hand detection unit indicating that the hand has been detected; Equipped with The control unit is a voltage estimation circuit that estimates a voltage value of the AC power supply; a control circuit for controlling energization of the heater in response to the voltage value; having The hand dryer is characterized in that the control circuit gradually increases a heater power supply rate, which is the ratio of the period during which power is supplied to the heater to a predetermined period, when the time during which power is supplied to the heater has elapsed a predetermined time.

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