JP6056008B2 - Air purifier - Google Patents

Description

  The present invention relates to an air cleaning device having overcurrent protection of an electrode unit.

  Conventionally, overcurrent protection of an electrode unit of an air cleaning device of this type is usually performed by supplying water with high conductivity to the electrode unit and performing electrolytic treatment by supplying a direct current to the electrode unit. There is one that cuts off the energization to the electrode unit by overcurrent protection provided in the power source for power (see, for example, Patent Document 1). Further, an overcurrent protection method is conceivable in which the device or current control is stopped when a predetermined current value is exceeded without relying on the overcurrent protection provided in the power supply for the electrode unit. In addition, for the purpose of small size and low cost, there is a configuration in which solid or granular salt is put into water supplied from a water supply tank, instead of preparing and storing water having high conductivity used for electrolytic treatment (for example, Patent Documents). 1).

JP 2003-290769 A

  In such a conventional air cleaning device, since it relies on the overcurrent protection provided in the power supply for the electrode unit, it stops depending on the power supply, and it is supplied to the electrode unit whether the overcurrent protection of the power supply worked. A separate means for determining whether there is an abnormality in water is necessary.

  In particular, in the configuration using a solid salt, the conductivity of water is non-uniform until the salt is dissolved in water, and the conductivity is lower in the vicinity of the electrode unit than in the vicinity of the added salt. In this state, if there is water supply from the water supply tank to the tray or vibration applied from the outside, the water in the tray moves suddenly, so that high-concentration salt water spreads between the electrode units, and the conductivity increases rapidly. There was.

  In this case, when a constant voltage is applied to the electrodes, the electrode current value becomes larger than the target current value, and therefore constant current control is performed to reduce the voltage supplied to the electrode unit.

  If the control cycle of this constant current control is short, followability is good when the change in conductivity is large, but overshoot or chattering occurs when the change in conductivity is small or when energization of the electrode is started, and the electrode current value is the target. Current control becomes unstable because it becomes larger or smaller than the current value.

  Also, if the control cycle is long, it is good if the change in conductivity is small, but if the change in conductivity is large, the voltage cannot be reduced in time, and a large current flows through the electrode unit and its control circuit. Had a problem that it was burdensome.

  In general, when considering circuit protection, it is better that the overcurrent protection current value has a smaller increment than the control current value. However, when the increase is small, that is, when the overcurrent protection current value is set to a small value, there is a problem that erroneous detection may occur due to an increase in current due to a sudden increase in conductivity around the electrode unit due to the reason. It was.

  Correspondingly, in order to solve the above-mentioned problems, a method of using a component with a large rated current value or rated power value as well as a long constant current control cycle and a large overcurrent protection current value. However, not only was the circuit component expensive, but also the excessive current flow caused the life of the electrode unit to be shortened, making it impractical.

  Therefore, the present invention solves the above-mentioned conventional problems, even when the conductivity around the electrode unit suddenly increases due to water supply from the water supply tank to the tray, vibration from the outside, etc. An object of the present invention is to provide an air cleaning device having an overcurrent protection for an electrode unit that can reduce the possibility of erroneous detection and prevent the life of the electrode unit from being shortened.

  In order to achieve this object, the present invention provides a housing with a removable water supply tank, a filter member to which water in the water supply tank is supplied, and the water in the water supply tank. A tray that forms a feed water channel leading to the filter member and is provided with a salt feed port for feeding a salt tablet from the outside, a filter rotating means that allows the filter member to rotate, and electrolyzes the water in the feed water channel An electrode having an overcurrent protection unit for the electrode unit, an air blower for bringing the filter member into contact with air, and controlling the energization of the electrode unit to be a constant current within a target current value range An air cleaning device comprising a control means, wherein the electrode control means supplies a transistor for supplying a current to the electrode unit and a collector voltage of the transistor. A CDC converter; a base voltage supply circuit that supplies a base voltage to the transistor; a DCDC converter output voltage switching circuit that switches the output voltage of the DCDC converter to a plurality of stages; and a current detection circuit that detects a current flowing through the electrode unit; Constant current control for giving an instruction at a predetermined control cycle with a certain correlation between the base voltage supply circuit and the DCDC converter output switching circuit so that the current value detected by the current detection circuit falls within a target current range And an overcurrent protection unit that detects an overcurrent from the current detected by the current detection circuit to the electrode unit and stops the operation of the air cleaner, and the DCDC converter passes the DCDC converter over the DCDC converter. The DC / DC converter has an overcurrent protection function for protecting from current, and the overcurrent protection unit When the predetermined value A smaller than the current value at which the overcurrent protection function for the DCDC converter operates exceeds a predetermined time A shorter than the control cycle, the base voltage supply of the transistor is stopped to protect the transistor and the electrode unit. The electrode control protection means A for stopping energization of the electrode unit and the current value B smaller than the predetermined value A are shorter than the predetermined time A so that the electrode control protection means A does not work easily. An electrode that lowers the base voltage of the transistor to near the lower limit by the base voltage supply circuit when the predetermined time B is exceeded, and lowers the set voltage of the DCDC converter output voltage switching circuit having the correlation to the lower limit voltage. The indicated value of the control protection means B and the base voltage supply circuit is a lower limit value, and the current value C is smaller than the current value B. When the predetermined period C longer than the control cycle is exceeded, it is determined that the conductivity of the tray water is excessively high, and the base voltage supply of the transistor is stopped to prevent the life of the electrode unit from being reduced. And an electrode control protection means C for stopping energization of the unit, and the electrode unit and the transistor are protected from an overcurrent to the electrode unit. To achieve.

  According to the present invention, a detachable water supply tank, a filter member to which water in the water supply tank is supplied, and a water supply channel for guiding the water in the water supply tank to the filter member are provided in the housing. A tray that is formed and provided with a salt inlet for feeding salt tablets from the outside, a filter rotating means that allows the filter member to rotate, an electrode unit that electrolyzes the water in the supply water channel, and the filter member An air cleaner comprising: a blower that contacts air; and an electrode control unit that controls energization of the electrode unit to be a constant current within a target current value range and includes an overcurrent protection unit for the electrode unit. The electrode control means includes a transistor that supplies a current to the electrode unit, a DCDC converter that supplies a collector voltage of the transistor, and the transistor. A base voltage supply circuit for supplying a base voltage to the transistor, a DCDC converter output voltage switching circuit for switching the output voltage of the DCDC converter to a plurality of stages, a current detection circuit for detecting a current flowing through the electrode unit, and the current detection circuit A constant current control unit that gives a constant correlation between the base voltage supply circuit and the DCDC converter output switching circuit so that the detected current value falls within a target current range, and issues an instruction at a predetermined control period; and In order to protect the DCDC converter from overcurrent, the overcurrent protection unit detects the overcurrent from the current detected by the detection circuit to the electrode unit and stops the operation of the air cleaner. DCDC converter overcurrent protection function, wherein the overcurrent protection unit is the DCDC converter overcurrent When the predetermined value A smaller than the current value at which the protective function operates exceeds a predetermined time A shorter than the control period, the base voltage supply of the transistor is stopped to protect the transistor and the electrode unit, and the electrode unit The electrode control protection means A for stopping energization of the current and the current value B smaller than the predetermined value A exceed the predetermined time B shorter than the predetermined time A so that the electrode control protection means A does not work easily. In this case, the base voltage supply circuit lowers the base voltage of the transistor to near the lower limit value, and also lowers the set voltage of the DCDC converter output voltage switching circuit having the correlation to the lower limit voltage; , The indicated value of the base voltage supply circuit is a lower limit value, and a current value C smaller than the current value B is a predetermined value longer than the control cycle. When the time C is exceeded, it is determined that the conductivity of the tray water is excessively high, the base voltage supply of the transistor is stopped to prevent the life of the electrode unit from being reduced, and the electrode that stops energizing the electrode unit And having a control protection means C, and by protecting the electrode unit and the transistor from overcurrent to the electrode unit, when the salt tablet is inserted, the state of non-uniform conductivity of water is in the tray. Even if the electrical conductivity around the electrode unit suddenly increases when water is supplied from the water supply tank to the tray or is subjected to external vibration, the current detection circuit The electrode control protection means B detects the current due to a sudden change in the current, and the electrode control protection means B detects the predetermined time that is earlier than the predetermined time A when the current exceeds the current value B and stops current control. The base voltage is reduced by the base voltage supply circuit, so that the voltage applied to the electrode unit can be reduced, that is, the current to the electrode unit is reduced before the electrode control protection means A operates. be able to. Thereby, the erroneous detection of overcurrent protection can be reduced.

  Furthermore, by separating the electrode control protection means A and the electrode control protection means C, and by making the current value C of the electrode control protection means C smaller than the current value B of the electrode control protection means B, even when the control range is exceeded, It can be prevented that the current increases beyond the current value C, the current continues to flow, and the life of the electrode unit is shortened.

  In other words, it is possible to provide an air cleaning device provided with overcurrent protection of an electrode unit that can reduce the possibility of erroneous detection and prevent the life of the electrode unit from being shortened.

Overview of the air purifier according to Embodiment 1 of the present invention Cross section of the air cleaning device Top surface side perspective view of the tray used for this Embodiment 1. FIG. Top view of the tray Block diagram of electrode control means used in Embodiment 1 of the present invention Block diagram of a DCDC converter ON / OFF switching circuit used in Embodiment 1 of the present invention Block diagram of the base voltage supply circuit Block diagram of the same current detection circuit Flow chart of operation sequence of identification current controller Flow chart of identification current operation sequence Comparison of base voltage indication value and DCDC converter output level when the base voltage drops Comparison of base voltage indication value and DCDC converter output level when base voltage rises Flow chart of operation sequence of electrode control protection means A Flow diagram of operation sequence of electrode control protection means B Flow diagram of operation sequence of electrode control protection means C

  The air purifier according to claim 1 of the present invention includes, in a housing, a removable water supply tank, a filter member to which water in the water supply tank is supplied, and the water in the water supply tank. A tray that forms a supply water channel that leads to the filter member and that is provided with a salt input port for supplying a salt tablet from the outside, a filter rotating means that can rotate the filter member, and an electrode that electrolyzes the water in the supply water channel Electrode control including a unit, a blower for bringing air into contact with the filter member, and an overcurrent protection unit for controlling the energization to the electrode unit so as to become a constant current within a target current value range And the electrode control means includes a transistor for supplying a current to the electrode unit, and a DCD for supplying a collector voltage of the transistor. A converter, a base voltage supply circuit that supplies a base voltage to the transistor, a DCDC converter output voltage switching circuit that switches the output voltage of the DCDC converter to a plurality of stages, a current detection circuit that detects a current flowing through the electrode unit, A constant current control unit for giving an instruction at a predetermined control period with a certain correlation between the base voltage supply circuit and the DCDC converter output switching circuit so that a current value detected by the current detection circuit falls within a target current range. And the overcurrent protection unit that detects an overcurrent from the current detected by the current detection circuit to the electrode unit and stops the operation of the air cleaner, and the DCDC converter The DC / DC converter has an overcurrent protection function for protecting from DC, and the overcurrent protection unit includes the DC / DC converter When the predetermined value A smaller than the current value at which the overcurrent protection function for the C converter operates exceeds the predetermined time A shorter than the control cycle, the base voltage supply of the transistor is stopped to protect the transistor and the electrode unit. The electrode control protection means A for stopping energization of the electrode unit and the current value B smaller than the predetermined value A are shorter than the predetermined time A so that the electrode control protection means A does not work easily. An electrode that lowers the base voltage of the transistor to near the lower limit by the base voltage supply circuit when the predetermined time B is exceeded, and lowers the set voltage of the DCDC converter output voltage switching circuit having the correlation to the lower limit voltage. The indication value of the control protection means B and the base voltage supply circuit is a lower limit value, and the current value C smaller than the current value B is When a predetermined time C longer than the control period is exceeded, it is determined that the conductivity of the tray water is excessively high, and the base voltage supply of the transistor is stopped to prevent the life of the electrode unit from being reduced. And the electrode control protection means C for stopping the energization of the electrode unit, and the electrode unit and the transistor are protected from an overcurrent to the electrode unit.

  Thereby, at the time of normal operation, that is, when the change in the conductivity of the tray water is small, the constant current control unit works to stabilize the current flowing to the electrode unit. Even in this state, if a salt tablet is inserted, a state in which the conductivity of water is uneven in the tray occurs, and the electrode is supplied when water is supplied from the water supply tank to the tray or when it receives vibration from the outside. The conductivity around the unit suddenly increases. However, the current detection circuit detects a current due to an abrupt change in conductivity, and the electrode control protection means B is less than the predetermined time A when the time when the current exceeds the current value B is stopped. When the predetermined time B is reached early, the base voltage supply circuit lowers the base voltage and the applied voltage to the electrode unit can be lowered, that is, before the electrode control protection means A operates, Current can be reduced. Thereby, the erroneous detection of overcurrent protection can be reduced.

  Further, as the base voltage supply circuit lowers the base voltage, the DCDC converter output voltage switching circuit lowers the output voltage of the DCDC converter to the lower limit value, thereby reducing the load on the DCDC converter and the constant current. Since the loss of the transistor can be reduced, the component can be made small or inexpensive.

  Further, when an excessive current flows through the constant current control means due to a short circuit of the electrode unit, etc., even if the electrode control protection means B works to reduce the current to the electrode unit, the overcurrent protection for the DCDC converter provided in the DCDC converter is provided. There is a possibility that the constant current transistor will be destroyed when a current value at which the function is activated flows. However, since the current value A at which the electrode control protection means A operates is set to a value smaller than the current value at which the overcurrent protection function for the DCDC converter operates, the electrode control protection means A operates before the constant current transistor breaks down. This energizes the electrode unit, that is, interrupts the current of the constant current transistor. Therefore, a current value for protecting the constant current transistor can be set regardless of the overcurrent protection function of the DCDC converter, and the constant current transistor can be made small or inexpensive.

  Furthermore, by separating the electrode control protection means A and the electrode control protection means C, and by making the current value C of the electrode control protection means C smaller than the current value B of the electrode control protection means B, even when the control range is exceeded, There is an effect that it is possible to prevent the current from increasing by exceeding the current value C, to keep the current from flowing, and to shorten the life of the electrode unit.

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

(Embodiment 1)
As shown in FIG. 1, the air purifier provided with the overcurrent protection of the electrode unit includes a suction port 11 on both side surfaces of the housing 36 and a blower port 12 on the top surface.

  As shown in FIG. 2, a water supply tank 1 that can be attached to and detached from the tray 5, a filter member 2 to which water in the water supply tank 1 is supplied, and the filter member 2 can be rotated. A combination mechanism of a motor and a gear as the filter rotating means 6, an electrode unit 7 for electrolyzing the water in the supply water channel 3, a blower 8 for bringing air into contact with the filter member 2, and the electrode unit 7 An electrode control means 9 including an overcurrent protection unit 10 for controlling the energization so as to become a constant current within a target current value range, for example, within a target current value range of 0.8 A ± 5%, is provided. ing.

  Further, as shown in FIG. 3, the tray 5 has a supply water channel 3 for guiding the water in the water supply tank 1 to the filter member 2 and is provided with a salt inlet 4 for feeding salt tablets from the outside. Yes.

  The supply water channel 3 is provided on the outlet side of the first supply water channel 3a, the second supply water channel 3b located below the filter member 2, and the first supply water channel 3a located below the water supply tank 1. The electrode water channel 3c is connected to the inlet side of the second supply water channel 3b.

  The salt inlet 4 is in the first supply water channel 3a. The electrode unit 7 is disposed in the electrode water channel 3c.

  The water to be supplied sequentially passes through the first supply water channel 3a, the salt inlet 4, the electrode water channel 3c, and the second supply water channel 3b along the supply water channel 3 as indicated by arrows in FIG. It is.

  As shown in FIG. 4, the filter member 2 is provided with a water absorbent fiber material on the outer peripheral surface of the cylindrical member and is rotated by the filter rotating means 6. And the filter member 2 fulfill | performs the gas-liquid contact function which makes the passing air contact electrolyzed water, and disinfects air.

  The electrode unit 7 has at least a pair of electrodes inside, and the electrodes are immersed in the water in the tray 5. And in this state, by applying a DC voltage between the electrodes using the electrode control means 9, the water is electrolyzed to generate electrolyzed water.

  Water containing chloride ions is electrolyzed to produce electrolyzed water containing hypochlorous acid. Hypochlorous acid is contained in reactive oxygen species and has a strong oxidizing action and bleaching action. The aqueous solution in which hypochlorous acid is dissolved, that is, the generated electrolyzed water, exhibits various air cleaning effects such as inactivation of viruses and the like, sterilization, and decomposition of organic compounds.

  Increasing the chloride ion concentration increases the amount of hypochlorous acid generated. In the present embodiment, the salt ion of water in the tray 5 is introduced by feeding a salt tablet into the salt inlet 4. The concentration is increasing.

  FIG. 5 shows a block diagram of the electrode control means 9.

  The electrode control means 9 includes a constant current NPN transistor as a transistor 15 for supplying a current to the electrode unit 7, a DCDC converter 13 for supplying a collector voltage of the transistor 15, and a base voltage to the transistor 15. A base voltage supply circuit 17 to be supplied, a DCDC converter output switching circuit 18 for switching the output voltage of the DCDC converter 13 to a plurality of stages, a DCDC converter ON / OFF switching circuit 19 for switching operation start and stop of the DCDC converter 13, A current detection circuit 16 for detecting the current flowing through the electrode unit 7, and the base voltage supply circuit 17, the DCDC converter output switching circuit 18, and the DCDC converter ON / OFF switching based on the detection value from the current detection circuit 16. Circuit 19 It issues an instruction signal, and consists of the constant current control unit 20 for including an overcurrent protection portion 10 therein.

  The DCDC converter 13 is, for example, a step-down DCDC converter. That is, a DCDC converter overcurrent protection function 14 is provided that stops the output of the DCDC converter 13 when the output current of the DCDC converter 13 exceeds a certain value, for example, 3A. The DCDC converter 13 determines an output voltage based on a signal given from the DCDC converter output switching circuit 18.

  The DCDC converter 13 stops the output in response to a signal from the DCDC converter ON / OFF switching circuit 19.

  Further, as shown in FIG. 6, the DCDC converter output switching circuit 18 includes resistors 21a to 21h for determining the eighth output level from the first output level, transistors, SW22a-22h which consists of etc., and resistor 21i, and turns on any one SW of said SW22a-22h by the signal from the said constant current control part 20.

  For example, at the first output level, the constant current control unit 20 outputs a signal for turning on the SW 22a, and the DCDC converter 13 is arranged in series between the output voltage 23 of the DCDC converter and the circuit ground 37. The output voltage 23 of the DCDC converter is changed so that the divided voltage of the resistor 21a and the resistor 21i becomes a constant voltage.

  The base voltage supply circuit 17 shown in FIG. 5 supplies the base voltage of the transistor 15.

  That is, as shown in FIG. 7, a resistor 24 a that inputs a base voltage instruction value such as a PWM signal output from the constant current control unit 20 at one end and a capacitor 25 that connects the other end of the resistor 24 a to a circuit ground 37. And a smoothing circuit composed of a resistor 24b connected in parallel to the capacitor 25, and an amplifier circuit for amplifying the voltage between the terminals of the resistor 24b.

  The amplifier circuit forms a non-inverting amplifier by an operational amplifier 26 and resistors 24c and 24d.

  The current detection circuit 16 amplifies the detected current flowing through the electrode unit 7 and outputs the amplified current to the constant current control unit 20.

  As shown in FIG. 8, a non-inverting amplifier including an operational amplifier 28 for amplifying a voltage generated in the current detection resistor 27 and resistors 29a and 29b is provided.

  The constant current control unit 20 performs an initial operation sequence 30 for starting current supply to the electrode unit 7 shown in FIG. 9 and a constant current operation sequence 31 for controlling the current flowing in the electrode unit 7 to be in a target current value range. It is equipped with.

According to the initial operation sequence 30, the current supply to the electrode unit 7 is started,
The constant current operation sequence 31 outputs an instruction signal to the base voltage supply circuit 17, the DCDC converter output switching circuit 18, and the DCDC converter ON / OFF switching circuit 19 based on the detected value from the current detection circuit 16. Thus, the current flowing through the electrode unit 17 is controlled so as to fall within the target current value range. In addition, the operation sequence 32 of the electrode control protection means A, the operation sequence 33 of the electrode control protection means B, and the operation sequence 34 of the electrode control protection means C provided in parallel move independently to meet their respective purposes. Overcurrent protection will be performed.

  The initial operation sequence 30 is composed of three steps.

  In the first step (S1), the output level of the DCDC converter 13 is set to the lower limit value, that is, the first output level, and the instruction signal is output to the DCDC converter output switching circuit 18.

  The second step (S2) is to start the operation of the DCDC converter 13 via the DCDC converter ON / OFF switching circuit 19.

  In the third step (S3), the initial value of the PWM ON duty is output to the base voltage supply circuit 17 at 10%, for example, and the base voltage of the transistor 15 is supplied.

  The constant current operation sequence 31 includes an operation sequence 32 of the electrode control protection means A that performs overcurrent protection according to each purpose, an operation sequence 33 of the electrode control protection means B, and an operation of the electrode control protection means C. The sequence 34 is also provided in parallel.

  Next, the constant current operation sequence 31 will be described with reference to FIG.

  The constant current operation sequence 31 includes 10 steps from the fourth step to the thirteenth step.

  First, as the first step, the fourth step (S4) is to reset a control period for performing constant current control, for example, a period timer 35 that counts 500 ms.

  In the fifth step (S5), the period timer 35 is started.

  In the sixth step (S6), it is determined whether or not the period timer 35 is equal to or longer than the control period.

  In the seventh step (S7), the electrode current value detected by the current detection circuit 16 is read when the cycle timer 35 is equal to or longer than the control cycle in the sixth step.

  The eighth step (S8) is to determine whether or not the electrode current value detected by the current detection circuit 16 exceeds the target current value 0.8A + 5% of the electrode current.

  In the ninth step (S9), the electrode current value detected by the current detection circuit 16 when it is determined in the eighth step that the electrode current value is not larger than + 5% of the target value is the target current value of the electrode current. It is discriminate | determined whether it is less than 0.8A-5%.

  In the tenth step (S10), when it is determined in the eighth step that the electrode current value is larger than + 5% of the target value, the indication value of the PWM ON duty is lowered by, for example, one step to the base voltage supply circuit 17. The voltage is output to lower the base voltage of the transistor 15, and the electrode current value is lowered.

  In the eleventh step (S11), following the tenth step, an instruction to the DCDC converter output switching circuit 18 is made according to the correlation between the base voltage instruction value when the base voltage drops and the DCDC converter output level comparison diagram shown in FIG. The signal is changed, and the loss applied to the transistor 15 during normal operation is reduced.

  In the twelfth step (S12), when it is determined in the ninth step that the electrode current value is less than the target current value 0.8A-5% of the electrode current, the indication value of the PWM ON duty is, for example, one step. The voltage is raised and output to the base voltage supply circuit 17 to increase the base voltage of the transistor 15 and increase the electrode current value.

  In the thirteenth step (S13), following the twelfth step, an instruction to the DCDC converter output switching circuit 18 is made according to the correlation between the base voltage instruction value when the base voltage rises and the DCDC converter output level comparison diagram shown in FIG. The signal is changed, and the loss applied to the transistor 15 during normal operation is reduced.

  Therefore, when the electrode current value is larger than the target current value range, the electrode current value is lowered so that the electrode current value falls within the target current value range by repeating S4 to S8, S10, S11, and S4. Become.

  When the electrode current value is smaller than the target current value range, the electrode current value is lowered so that the electrode current value is within the target current value range by repeating S4 to S9, S12, S13, and S4. Become.

  Further, when the electrode current value is within the target current value range, the electrode current value is not increased or decreased.

  Next, the operation sequence 32 of the electrode control protection means A will be described with reference to FIG.

  The operation sequence 32 of the electrode control protection means A is composed of 11 steps from the 14th step to the 24th step.

  In the fourteenth step (S14), the electrode current value detected by the current detection circuit 16 is read.

  The fifteenth step (S15) is to determine whether or not the electrode current value detected by the current detection circuit 16 exceeds a predetermined value A, for example, 2A.

  The sixteenth step (S16) is to start a timer A that measures a predetermined time A that is shorter than the control period, for example, 200 ms.

  In the seventeenth step (S17), the electrode current value detected by the current detection circuit 16 is read within a predetermined time A after the timer A is started in the sixteenth step.

  In an eighteenth step (S18), it is determined whether or not the electrode current value read in the seventeenth step is larger than a predetermined value A.

  The nineteenth step (S19) is to reset the timer A.

  In the twentieth step (S20), when it is determined in the eighteenth step that the electrode current value is larger than the predetermined value A, it is determined whether or not the timer A is larger than the predetermined time A.

  In the twenty-first step (S21), when it is determined in the twentieth step that the timer A is greater than the predetermined time A, the indication value of the PWM ON duty is set to 0 and output to the base voltage supply circuit 17. The base voltage supply to the transistor 15 is stopped, and the current supply to the electrode unit 7 is stopped.

  In the twenty-second step (S22), following the twenty-first step, the instruction signal to the DCDC converter output switching circuit 18 is set to the lower limit value, that is, the first output level and output.

  In the 23rd step (S23), the operation of the DCDC converter 13 is stopped through the DCDC converter ON / OFF switching circuit 19 following the 22nd step.

  In the 24th step (S24), the timer A is reset following the 23rd step.

  Accordingly, when the electrode current value exceeds a predetermined value A, for example, 2A, for a predetermined time A, the supply of the base voltage to the transistor 15 is stopped to cut off the current supply to the electrode unit 7, and then the DCDC converter. The operation of No. 13 is stopped and the constant current control is ended.

  Next, the operation sequence 33 of the electrode control protection means B will be described with reference to FIG.

  The operation sequence 33 of the electrode control protection means B is composed of 10 steps from the 25th step to the 34th step.

  In the twenty-fifth step (S25), the electrode current value detected by the current detection circuit 16 is read.

  In the twenty-sixth step (S26), it is determined whether or not the electrode current value read in the twenty-fifth step exceeds a predetermined value B, for example, 1.1A.

  The twenty-seventh step (S27) starts a timer B that measures a predetermined time B shorter than the predetermined time A, for example, 50 ms, when it is determined in the twenty-sixth step that the electrode current value exceeds the predetermined value B. It is.

  In the twenty-eighth step (S28), the electrode current value detected by the current detection circuit 16 is read within a predetermined time A after the timer B is started in the twenty-seventh step.

  In the 29th step (S29), it is determined whether or not the electrode current value read in the 28th step exceeds a predetermined value B, for example, 1.1A.

  The thirtieth step (S30) is to reset the timer B when it is determined in the twenty-ninth step that the electrode current value does not exceed the predetermined value B.

  The thirty-first step (S31) is for determining whether or not the timer B is equal to or longer than the predetermined time B when it is determined in the twenty-ninth step that the electrode current value exceeds the predetermined value B. .

  In a thirty-second step (S32), when the timer B is equal to or longer than the predetermined time B in the thirty-first step, a lower limit value of PWM ON duty, that is, 10.0% is output to the base voltage supply circuit 17. Thus, the base voltage of the transistor 15 is lowered to the lower limit value, and the electrode current value is lowered to the lower limit value.

  In a thirty-third step (S33), following the thirty-second step, an instruction to the DCDC converter output switching circuit 18 is made in accordance with the correlation between the base voltage instruction value when the base voltage drops and the DCDC converter output level comparison table shown in FIG. A signal is output.

  The 34th step (S34) is to reset the timer B following the 33rd step.

  Therefore, when the electrode current value exceeds a predetermined value B, for example, 1.1A, for a predetermined time B, the current supply to the electrode unit 7 is reduced to the lower limit value by decreasing the base voltage supply to the transistor 15 to the lower limit value. To reduce the potential difference between the emitter and the collector of the transistor 15 by reducing the output voltage of the DCDC converter 13 by preventing the electrode control protection means A from working. This loss is reduced.

  Next, the operation sequence 34 of the electrode control protection means C will be described with reference to FIG.

  The operation sequence 34 of the electrode control protection means C is composed of 12 steps from the 35th step to the 46th step.

  The thirty-fifth step (S35) is to determine whether or not the indication value of the PWM ON duty to the base voltage supply circuit 17 is a lower limit value, that is, 10.0%.

  The thirty-sixth step (S36) is to read the electrode current value detected by the current detection circuit 16 following the thirty-fifth step.

  In a thirty-ninth step (S39), the electrode current value detected by the current detection circuit 16 is read within a predetermined time C after the timer C is started in the thirty-eighth step.

  In a thirty-seventh step (S37), following the thirty-sixth step, it is determined whether or not the electrode current value detected by the current detection circuit 16 exceeds a predetermined value C that is smaller than the predetermined value B, for example 0.95A. Is.

  In the 40th step (S40), it is determined whether the electrode current value detected by the current detection circuit 16 following the 39th step exceeds a predetermined value C, for example, 0.95A, which is smaller than the predetermined value B. It is to be determined.

  The thirty-eighth step (S38) is to start a timer C that measures a predetermined time C longer than the control cycle, for example, 5 minutes.

  The 41st step (S41) is to reset the timer C when it is not determined in the 40th step that the electrode current value exceeds the predetermined value C smaller than the predetermined value B. .

  In the forty-second step (S42), is the timer C equal to or longer than the predetermined time C when it is determined in the forty step that the electrode current value exceeds the predetermined value C smaller than the predetermined value B? It is to determine whether or not.

  In a forty-third step (S43), when it is determined in the forty-second step that the timer C is equal to or longer than the predetermined time C, the indication value of the PWM ON duty is set to 0 and output to the base voltage supply circuit 17. Thus, the supply of the base voltage to the transistor 15 is stopped, and the current supply to the electrode unit 7 is stopped.

  In the forty-fourth step (S44), following the forty-third step, the instruction signal to the DCDC converter output switching circuit 18 is set to the lower limit value, that is, the first output level and output.

  The 45th step (S45) is to stop the operation of the DCDC converter 13 through the DCDC converter ON / OFF switching circuit 19 following the 44th step.

  The 46th step (S46) is to reset the timer C following the 45th step.

  Therefore, when the electrode current value exceeds a predetermined value C, for example, 0.95 A, for a predetermined time C, the supply of the base voltage to the transistor 15 is stopped, and then the current supply to the electrode unit 7 is interrupted, The operation of the DCDC converter 13 is stopped and the constant current control is ended.

  Since the constant current control unit 20 enables the control as described above, an A / D input function capable of recognizing an analog voltage from a current detection circuit, a PWM output function to the base voltage supply circuit 17, A DCDC converter ON / OFF switching circuit 19 and a microcomputer capable of digital output to the DCDC converter output switching circuit 18 are used.

  With the above configuration, during a normal operation, that is, when the change in the conductivity of water in the tray 5 is small, the constant current operation sequence 31 is operated by the constant current control unit 20 and the current flowing to the electrode unit 7 is converted into a target current. It can be stabilized within the range. Even in this state, when a salt tablet is introduced, a state in which the electrical conductivity of water is uneven in the tray 5 occurs, and water is supplied from the water supply tank 1 into the tray 5 or from the outside. When subjected to vibration, the conductivity around the electrode unit 7 suddenly increases.

  However, the current detection circuit 16 detects a current due to a sudden change in conductivity, and stops current control when the current exceeds the predetermined value B by the operation sequence 33 of the electrode control protection means B. When the predetermined time B that is earlier than the predetermined time A is reached, the base voltage supply circuit 17 lowers the base voltage, so that the voltage applied to the electrode unit 7 can be lowered. Before the protection means A is activated, the current to the electrode unit 7 can be reduced. Thereby, erroneous detection of overcurrent protection can be reduced.

  Further, as the base voltage supply circuit 17 lowers the base voltage, the DCDC converter output switching circuit 18 lowers the output voltage of the DCDC converter to the lower limit value, thereby reducing the load on the DCDC converter 13. In addition, since the loss of the transistor 15 can be reduced, the parts can be made smaller or less expensive.

Furthermore, when an excessive current flows through the electrode control means 9 due to a short circuit of the electrode unit 7 or the like,
Even if the electrode control protection means B is activated and the current to the electrode unit 7 is reduced, the transistor 15 is destroyed when the current value for the DCDC converter overcurrent protection function 14 included in the DCDC converter 13 flows. There is a possibility that. However, since the predetermined value A of the current that the electrode control protection means A operates is set to a value smaller than the current value that the overcurrent protection function 14 for the DCDC converter operates, the electrode control protection before the transistor 15 breaks down. The means A works to cut off the energization of the electrode unit 7, that is, the current of the transistor 15. Therefore, regardless of the overcurrent protection function of the DCDC converter 13, a current value for protecting the transistor 15 can be set, and the transistor 15 can be made small or inexpensive.

  Further, when the control range is exceeded by separating the electrode control protection means A and the electrode control protection means C and making the predetermined value C of the electrode control protection means C smaller than the predetermined value B of the electrode control protection means B However, it is possible to prevent the current from increasing to the predetermined value C or more and the current from continuing to flow through the electrode unit 7, thereby preventing the life of the electrode unit 7 from being shortened.

  The air purifier provided with the overcurrent protection of the electrode unit according to the present invention can be applied to a small and inexpensive humidifier with a water purifying function.

DESCRIPTION OF SYMBOLS 1 Water supply tank 2 Filter member 3 Supply water path 3a 1st supply water path 3b 2nd supply water path 3c Electrode water path 4 Salt inlet 5 Tray 6 Filter rotation means 7 Electrode unit 8 Blower 9 Electrode control means 10 Overcurrent protection part 11 Suction port 12 Outlet 13 DCDC converter 14 Overcurrent protection function for DCDC converter 15 Transistor 16 Current detection circuit 17 Base voltage supply circuit 18 DCDC converter output switching circuit 19 DCDC converter ON / OFF switching circuit 20 Constant current control unit 21a Resistance 21b Resistance 21c resistor 21d resistor 21e resistor 21f resistor 21g resistor 21h resistor 21i resistor 22a SW
22b SW
22c SW
22d SW
22e SW
22f SW
22g SW
22h SW
23 DCDC converter output voltage 24a resistance 24b resistance 24c resistance 24d resistance 25 capacitor 26 operational amplifier 27 current detection resistance 28 operational amplifier 29a resistance 29b resistance 30 initial operation sequence 31 constant current operation sequence 32 operation sequence of electrode control protection means A 33 electrode control protection Operation sequence of means B 34 Operation sequence of electrode control protection means C 35 Period timer 36 Case 37 Circuit ground

Claims (1)

In the housing, a removable water supply tank, a filter member to which water in the water supply tank is supplied, a supply water channel for guiding the water in the water supply tank to the filter member are formed, and salt is externally provided. A tray provided with a salt inlet for inserting a tablet, a filter rotating means for rotating the filter member, an electrode unit for electrolyzing the water in the supply water channel, and a blower for bringing air into contact with the filter member An air cleaning apparatus comprising: an electrode control means that controls the energization of the electrode unit to be a constant current within a target current value range and includes an overcurrent protection unit for the electrode unit, The electrode control means includes a transistor for supplying a current to the electrode unit, a DCDC converter for supplying a collector voltage of the transistor, and a base for the transistor. A base voltage supply circuit for supplying a voltage; a DCDC converter output voltage switching circuit for switching the output voltage of the DCDC converter to a plurality of stages; a current detection circuit for detecting a current flowing through the electrode unit; and a detection by the current detection circuit A constant current control unit that gives a constant correlation between the base voltage supply circuit and the DCDC converter output switching circuit so that a current value falls within a target current range and issues an instruction at a predetermined control cycle; and the current detection circuit includes: The DC / DC converter includes a DC / DC converter for protecting the DC / DC converter from over current, the over current protection unit detecting an over current from the detected current to the electrode unit and stopping the operation of the air purifier. It has an overcurrent protection function, and the overcurrent protection unit is a current value at which the overcurrent protection function for the DCDC converter operates. When a predetermined value A that is smaller than a predetermined time A shorter than the control cycle exceeds the transistor and the electrode unit, the base voltage supply of the transistor is stopped and the energization to the electrode unit is stopped. When the current value B smaller than the predetermined value A exceeds the predetermined time B shorter than the predetermined time A so that the electrode control protecting means A and the electrode control protective means A do not work easily, the base Electrode control protection means B for lowering the base voltage of the transistor to near the lower limit value by the voltage supply circuit and lowering the set voltage of the DCDC converter output voltage switching circuit to the lower limit voltage, and the base voltage supply circuit Is the lower limit value, and the current value C smaller than the current value B is exceeded for a predetermined time C longer than the control cycle. In addition, electrode control protection means C that determines that the conductivity of the tray water is excessively high, stops the supply of the base voltage of the transistor to prevent a decrease in the life of the electrode unit, and stops energization of the electrode unit; And an air cleaning device for protecting the electrode unit and the transistor from an overcurrent to the electrode unit.

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