JP7630649B2 - Hand Dryer - Google Patents

Description

The present disclosure relates to a hand drying device that dries wet hands by blowing air onto them.

To keep hands in a hygienic condition, it is necessary to dry hands hygienically after washing. To dry hands hygienically after washing, instead of wiping wet hands with a towel or handkerchief, hand dryers are used that spray a high-velocity air stream onto the hands to blow off any water adhering to the hands and dry them.

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 warm 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 wind.

An AC power source is used as the power source for the heater in a hand dryer. There are 100V AC power sources that supply AC voltages between 100V and 120V, and 200V AC power sources 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 sources are equipped with 100V heaters, and hand dryers used with 200V AC power sources 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.

Patent Document 1 discloses a method for standardizing motors regardless of power supply voltage. Patent Document 1 discloses a power supply device that detects the voltage value of an AC voltage, switches between voltage doubler rectification and full-wave rectification depending on the voltage value, and generates a DC voltage of the same voltage value to supply to a load. This makes it possible to mount a DC load, i.e., a motor, of the same specifications even in products that are used with AC power sources of different voltage values.

Patent No. 6297999

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 of an increase in the number of models and costs of hand dryers.

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.

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 set reference value, the control circuit reduces a heater energization rate, which is the rate of energization of the heater in a set period, compared to when the estimated voltage value is less than the reference value, and controls the heater energization rate by phase control .

The hand dryer disclosed herein has the advantage of being able to share heaters between products with different types of power supply voltages, without using heaters with different specifications for each type of power supply voltage.

FIG. 1 is a perspective view of a hand dryer according to a first embodiment; Cross-sectional view of a hand dryer according to a first embodiment. FIG. 2 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; Diagram for explaining the operating principle of phase control A flowchart showing an example of a procedure of a method for controlling a hand dryer according to the first embodiment. FIG. 13 is a diagram showing an example of heater control setting information. 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. FIG. 13 is a diagram showing an example of a relationship between a current-carrying time and power consumption in a hand dryer according to a second embodiment. 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. 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. 11 is a flowchart showing an example of a procedure of a heater output control method according to a fourth embodiment.

Below, the hand dryer according to an embodiment of the present disclosure is described in detail with reference to the drawings.

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.

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

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 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.

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

The hand dryer 1 has a front nozzle 11 and a rear nozzle 12 that spray airflow onto 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.

The hand dryer 1 includes a hand detection unit 15 that detects a hand inserted into the hand insertion section 2. The hand detection unit 15 is built into the back section 5. An example of the 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. The hand detection unit 15 detects the presence or absence of a hand in the hand insertion section 2 based on the angle of the infrared light incident on the light-receiving element. The hand detection unit 15 may be a sensor other than a distance measurement sensor as long as it is capable of detecting a hand inserted into the hand insertion section 2. The hand detection unit 15 may be built into the front section 4.

The hand dryer 1 is equipped with a heater 23 that heats the air flow sent to the ducts 13 and 14. The heater 23 is provided in the air passage between the blower 10 and the front nozzle 11 and the rear nozzle 12.

The housing 3 has an air intake 16 that draws in air. The air intake 16 is provided at the bottom 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.

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

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

Figure 3 is a diagram showing an example of the schematic configuration of the circuit of the control unit of the hand dryer according to embodiment 1. Note that Figure 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 is referred to as the microcomputer circuit 36.

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

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, but 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 to drive 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.

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 the power supply ratio, which is the ratio of the period of power supply to the heater 23 according to the magnitude of the voltage value of the AC power supply 40 in a specified period. This power supply ratio corresponds to the heater power supply ratio. The specified period can be one cycle of the voltage of the AC power supply 40. The timing of the 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.

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

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.

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 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 operating 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. In addition, 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 here, the timing for turning off the triac 32 is when 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.

Phase control is a control method in which the AC voltage is directly turned on or off by the triac 32 to vary the applied voltage, and the timing of the on and off times is adjusted 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.

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 ON command GI1 is output from the microcomputer circuit 36 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.

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. In other words, 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.

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%. Also, 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 cycle 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 electricity is supplied to the heater 23 in one cycle, which is a set period. If the time during which the triac 32 is on, i.e., the time during which electricity is supplied to the heater 23, is long within one cycle, 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.

In this way, the voltage applied to the heater 23 changes at the timing when the microcomputer circuit 36 outputs the on-commands GI1, GI2, and GI3 to the gate of the triac 32, so 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 the zero-cross. The microcomputer circuit 36 determines the timing of outputting the ON commands GI1, GI2, and GI3 to the gate of the triac 32 so as to obtain a conduction angle according to the value of the output voltage, based on the power supply zero cross point.

Note that, although an example of controlling the proportion of current supplied to the heater 23 using phase control has been shown here, the proportion of current supplied to the heater 23 may also be controlled using current rate control.

Next, a control method by the control unit 30 of the hand dryer 1 according to this 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 the 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.

First, when the power supply of the hand dryer 1 is turned on, the voltage detection circuit 34 detects the voltage of the DC bus power supply 33 and outputs the detection result, that is, the 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.

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 the 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.

Figure 6 is a diagram showing an example of heater control setting information. The heater control setting information corresponds to the voltage detection value of the DC bus power supply 33 and the conduction angle. Here, the range of the voltage detection value and the conduction angle are associated. 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 flow rate, is set.

Note that 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%. Also, 150V in the heater control setting information is a value that is a criterion for dividing the conduction angle settings, and corresponds to the reference value. The reference value here is 150V, but this is just one example and other values may be used. Also, the conduction angle in FIG. 6 is just one example and can be any value. However, the lower the voltage value of the AC power supply 40, the larger the conduction angle is set.

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 it is connected to a 100V AC power supply, and sets the conduction angle to 100% by referring to the heater control setting information. 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 it is connected to a 200V AC power supply, and sets the conduction angle to 50% by referring to the heater control setting information.

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 is not detected (No in step S13), the microcomputer circuit 36 enters a waiting state. If a hand is detected (Yes in step S13), that is, if the user's hand is inserted into the hand insertion unit 2, the microcomputer circuit 36 starts driving the heater according to the heater control setting 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.

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

Then, the microcomputer circuit 36 determines whether the hand is no longer detected by the hand detection unit 15 (step S16). If the hand is detected (No in step S16), the state of spraying the heated high-speed airflow toward the hand continues. If the hand is no longer detected (Yes in step S16), that is, if the hand is removed from the hand insertion unit 2, the microcomputer circuit 36 stops driving the heater (step S17), and the microcomputer circuit 36 stops driving the motor (step S18). Then, the process returns to step S13.

As described above, in the first embodiment, the zero-cross detection circuit 31 detects a power supply zero-cross point in the AC power supply 40, the voltage detection circuit 34 detects the voltage value of the DC bus power supply 33 that converts the AC power supply 40 into a DC power supply, the triac 32 connected in series to the heater 23, and the microcomputer circuit 36 that controls the voltage applied to the heater 23 according to the voltage detection value in the voltage detection circuit 34. The microcomputer circuit 36 sets the conduction angle to the 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. The microcomputer circuit 36 drives the heater 23 when a hand is inserted into the hand insertion section 2. At this time, when the microcomputer circuit 36 receives information indicating that a zero cross has been detected from the zero-cross detection circuit 31, it outputs an ON command to the triac 32 after a time corresponding to the set conduction angle has elapsed, and applies an AC voltage to the 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. In other words, 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.

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 it is connected to a 100V AC power supply, the conduction angle to the heater 23 is set 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 it is connected to a 200V AC power supply, the conduction angle to the heater 23 is set 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 hand dryers 1 according to the type of AC power supply 40. As a result, it is possible to have the effect of making the heater 23 common between products with 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.

In the explanation of FIG. 5 above, an example of changing the heater control setting is shown 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: 110V AC power source, 120V AC power source, and AC power source from 220V to 240V. In this case, when setting the conduction angle, it is sufficient to distinguish between cases for each voltage. That is, in the heater control setting, it is sufficient to determine the range of the voltage detection value and the conduction angle for each of the 110V AC power source, 120V AC power source, and AC power source from 220V to 240V. This makes it possible to further subdivide the power source voltage and set the conduction angle to the heater 23.

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 thereafter when the heater 23 is driven. In the second embodiment, a case will be shown in which the conduction angle is changed when the heater 23 is driven.

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 relative to the voltage value of the AC power supply 40, as the target conduction angle, starts current supply to the heater 23 at a conduction angle larger than the target conduction angle, and changes to the target conduction angle after a specified time has elapsed. In other words, the conduction angle in the heater control setting information becomes the target setting value. Then, the microcomputer circuit 36 sets the conduction angle to be larger than the target setting value when the heater 23 starts to be driven, and gradually decreases it to the target setting value. The timing and time for changing the conduction angle can be set arbitrarily.

Figure 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 shows the power-on time of the heater 23, and the vertical axis shows 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 setting value in a model compatible with a 200V AC power source. In graph G2, the target setting value of the conduction angle is 50%, but the conduction angle is changed from 100% to 90% to 80% to ... to 50%.

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 for a set number of times or 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 after a time corresponding to a conduction angle of 90% has elapsed. After issuing this ON command for a set number of times or time, the microcomputer circuit 36 performs the same process by lowering the conduction angle by 10 points at a time until the conduction angle becomes 50%.

As shown in graph G1, if the conduction angle is controlled to be constant without being changed, the temperature of the heater 23 will gradually rise over time until it reaches the target temperature. In contrast, as shown in graph G2, by setting the conduction angle larger than the target setting when the current starts to flow and then gradually decreasing it until it reaches the target setting, the temperature will rise rapidly at the start of the current. This makes it possible to reach the target temperature quickly.

In the second embodiment, when the microcomputer circuit 36 starts to pass current to 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 current is started to pass to the heater 23. In other words, 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 more quickly.

In the above explanation, a method for gradually reducing the conduction angle up to the target set value has been described. 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 greater than the target set value.

Furthermore, the above example is effective when a heater 23 for a model compatible with a 100V AC power source is used in the hand dryer 1 and a 200V AC power source is applied to the heater 23. However, by selecting a 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.

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.

The configuration of the hand dryer 1 in embodiment 3 is similar to that shown in embodiments 1 and 2, but the function of the microcomputer circuit 36 in the control unit 30 differs from that in embodiments 1 and 2. The following describes the differences from embodiments 1 and 2. The following also describes the hand dryer 1 as having the configuration of embodiment 2.

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 specified 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.

Figure 8 is a diagram showing an example of the relationship between the power supply time and the power consumption in the hand dryer according to the second embodiment. In this figure, the horizontal axis indicates the power supply time, and the vertical axis indicates the power consumption. Graph G11, which is shown by a solid line, shows the power consumption when the motor 21 is driven with a constant conduction angle, and graph G12, which is shown by a dashed line, shows the power consumption when the conduction angle to the heater 23 is gradually reduced. Graph G13, which is shown by a dashed line, shows 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 the power supply to the heater 23 is turned on, the conduction angle to the heater 23 is large, so the power consumed by the heater 23 is the largest during the power supply 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 the power supply, as shown in graph G13.

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 shows the power consumption when the conduction angle to the motor 21 is gradually increased, and graph G22 shown by a dashed line shows the power consumption when the conduction angle to the heater 23 is gradually decreased. Graph G23 shown by a dashed line shows 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 G22 in FIG. 9, the conduction angle to the heater 23 is large immediately after the energization of the heater 23, so the power consumed by the heater 23 is maximum during the energization time. On the other hand, in the third embodiment, as shown in 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 way, the power consumption of the entire load can be always kept constant, as shown in graph G23. Moreover, power consumption can be reduced compared to the case of FIG. 8, and energy saving can be improved.

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

In addition, in the control shown in Figure 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 Figure 9 of embodiment 3, the inrush current at startup can be suppressed, thereby reducing the possibility of failure of the electronic components of the power supply system.

In the above explanation, the conduction angle to the motor 21 is controlled, but the conduction angle to the motor 21 may also be controlled using phase control, current duty control, inverter control, etc.

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.

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

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 hand dryer 1 is used for a longer time. 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 it takes to dry.

Figure 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, the conduction angle is gradually changed from 100% to the target set value of 50% until the energization time of the heater 23 reaches 10 seconds. If the hand continues to be inserted in the hand insertion section 2 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 Figure 10, the conduction angle to the heater 23 is changed from 50% to 75%. Note that in Figure 10, an example is shown in which the time for increasing the set value of the conduction angle is 10 seconds, but this is just one example and can be any time.

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

In embodiment 4, when the microcontroller circuit 36 starts driving the heater in step S14, it starts timing (step S31).

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). After that, the microcomputer circuit 36 determines whether the hand is no longer detected by the hand detection unit 15 (step S34). If the hand is detected (if No in step S34), the state of spraying the heated high-speed airflow toward the hand continues. If the hand is no longer detected (if Yes in step S34), the process proceeds to step S17.

By this processing, when a user inserts his/her hand for a specified period of time or longer, the conduction angle to the heater 23 is increased, thereby raising the temperature of the high-velocity airflow compared to before the conduction angle to the heater 23 was increased, thereby improving the sensation of warm air for the user.

In the above explanation, the microcomputer circuit 36 has changed the set value to a predetermined conduction angle when the hand is inserted for a predetermined time or more. However, the microcomputer circuit 36 may also control the conduction angle to the heater 23 to gradually increase to the predetermined conduction angle when the time that electricity is supplied to the heater 23 has elapsed. This can improve the feeling of warm air without causing the user discomfort due to a sudden temperature change.

In addition, the above explanation describes the case where embodiment 4 is applied to the hand dryer 1 of embodiment 2, but embodiment 4 may also be applied to the hand dryer 1 of embodiments 1 and 3.

In the fourth embodiment, the microcomputer circuit 36 starts timing when the heater 23 starts to be energized, and if the heater 23 is energized for a set time or longer, the conduction angle to the heater 23 is increased. 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.

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.

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 section, 11 front nozzle, 12 rear nozzle, 13, 14, 17 duct, 15 hand detection section, 16 air intake, 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 (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, 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. 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. 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. 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. 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. 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. 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.

Images