Liquid level detection device and method for air conditioner hood and air conditioner hood

Abstract

The present invention belongs to the technical field of air conditioner smoke hoods, and discloses a liquid level detection device, method and air conditioner smoke hood for an air conditioner smoke hood. The device comprises: a constant current charging unit, which uses a constant current to charge a detection capacitor module; a control unit, which sends a discharge control signal after the detection capacitor module is fully charged in the current cycle; a discharge unit, which discharges the detection capacitor module under the control of the discharge control signal; a liquid level signal output unit, which processes the voltage of the detection capacitor module during the charging process of the detection capacitor module and outputs a detection signal in the current cycle; a liquid level signal is obtained in n cycles within a set time period; and a control unit, which determines the liquid level detection value of condensed water in a water tank according to the liquid level signal to detect the liquid level of condensed water in the water tank. The scheme realizes the liquid level detection of condensed water in the water tank by using a pair of electrodes, a constant current charging unit, a discharge unit and a liquid level signal output unit, and has good accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of air-conditioning hoods, and specifically relates to a liquid level detection device of an air-conditioning hood, an air-conditioning hood and a liquid level detection method thereof, and more particularly to a liquid level detection circuit of an air-conditioning hood, an air-conditioning hood having the liquid level detection circuit, and a liquid level detection method of the air-conditioning hood. Background Art

[0002] With the improvement of people's living standards and the development of science and technology, people have put forward higher requirements for the comfort of the kitchen, and the demand for air-conditioning hoods is becoming more and more urgent. Air-conditioning hoods will produce condensed water during operation, and its liquid level needs to be detected and discharged. In related solutions, the liquid level detection of air-conditioning hoods is generally carried out using special liquid level sensors or liquid level floats, which are easily affected by voltage fluctuations and temperature, and the detection accuracy is difficult to guarantee.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The object of the present invention is to provide a liquid level detection device for an air-conditioning hood, an air-conditioning hood and a liquid level detection method thereof, so as to solve the problem that the liquid level detection of the air-conditioning hood in the related scheme uses a special liquid level sensor or a liquid level float for detection, which is easily affected by voltage fluctuations and temperature and the detection accuracy is difficult to guarantee. The liquid level of condensed water in the water tank is detected by utilizing a pair of electrodes and a liquid level detection circuit, thereby achieving an effect of good detection accuracy.

[0005] The present invention provides a liquid level detection device for an air-conditioning hood, wherein the air-conditioning hood has a water tank, and the water tank is used to receive and store condensed water generated by the air-conditioning hood; the liquid level detection device for the air-conditioning hood comprises: a first electrode, a second electrode, a constant current charging unit, a discharging unit, a liquid level signal output unit, and a control unit; the first electrode and the second electrode form a pair of electrodes, and the pair of electrodes are placed in the water tank to form a detection capacitor module that can detect the liquid level of condensed water in the water tank and output a corresponding voltage; wherein the constant current charging unit is used to provide a constant current to the detection capacitor module so as to charge the detection capacitor module with the constant current; the control unit is used to, in the current cycle, determine that the voltage of the detection capacitor module has been When the preset maximum voltage threshold is reached, a discharge control signal is issued; the discharge unit is used to discharge the detection capacitor module under the control of the discharge control signal, so that the detection capacitor module can be recharged in the next cycle; the liquid level signal output unit is used to process the voltage of the detection capacitor module in the current cycle while the detection capacitor module is charging, and output the detection signal of the current cycle; in this way, the detection signal of n cycles within the set time period is obtained as the liquid level signal of the condensed water in the water tank; wherein n is a positive integer; the control unit is used to determine the liquid level detection value of the condensed water in the water tank according to the liquid level signal, so as to realize the detection of the liquid level of the condensed water in the water tank.

[0006] In some embodiments, the air conditioning hood further has a heat exchanger, and a preset watering device is arranged between the heat exchanger and the water tank; the control unit is also used to control the preset watering device to start when the liquid level detection value of the condensed water in the water tank reaches a preset detection value, so as to pour the condensed water in the water tank onto the heat exchanger of the air conditioning hood to cool the heat exchanger.

[0007] In some embodiments, the constant current charging unit includes: a voltage input module, a voltage following module, a constant voltage module, and a charging module; wherein the constant current charging unit provides a constant current to the detection capacitor module in the current cycle to charge the detection capacitor module using the constant current, including: the voltage input module, which is used to divide the voltage based on a preset DC power supply to obtain a divided voltage; the voltage following module, which is used to follow the divided voltage to obtain a following voltage; the constant voltage module, which is used to maintain a constant voltage on the following voltage to obtain a constant voltage; the charging module, which is used to generate a constant current based on the constant voltage, and use the constant current to charge the detection capacitor module.

[0008] In some embodiments, the voltage input module includes: a first voltage-dividing resistor module and a second voltage-dividing resistor module; the voltage follower module includes: a first operational amplifier module; the constant voltage module includes: a second operational amplifier module, a third voltage-dividing resistor module, and a fourth voltage-dividing resistor module; the charging module includes: a current-limiting resistor module; wherein the preset DC power supply is grounded after passing through the first voltage-dividing resistor module and the second voltage-dividing resistor module; the common end of the first voltage-dividing resistor module and the second voltage-dividing resistor module is connected to the in-phase input end of the first operational amplifier module; the inverting input end of the first operational amplifier module is connected to the inverting input end of the first operational amplifier module. The output end of an operational amplifier module; the output end of the first operational amplifier module is connected to the in-phase input end of the second operational amplifier module; the output end of the first operational amplifier module is connected to the first connection end of the detection capacitor module after passing through the current limiting resistor module; the output end of the first operational amplifier module is also connected to the output end of the second operational amplifier module; the second connection end of the detection capacitor module is grounded; the inverting input end of the second operational amplifier module is connected to the first connection end of the detection capacitor module; the output end of the second operational amplifier module is also connected to a preset reference voltage connection end after passing through the third voltage-dividing resistor module and the fourth voltage-dividing resistor module.

[0009] In some embodiments, the voltage follower module also includes: a third operational amplifier module; wherein the output end of the first operational amplifier module is connected to the non-inverting input end of the third operational amplifier module; the inverting input end of the third operational amplifier module is connected to the output end of the second operational amplifier module; the output end of the third operational amplifier module is connected to the non-inverting input end of the second operational amplifier module; the output end of the third operational amplifier module is connected to the first connection end of the detection capacitor module after passing through the current limiting resistor module; the output end of the third operational amplifier module is also connected to the output end of the second operational amplifier module.

[0010] In some embodiments, the discharge unit includes: a switch tube module and a discharge resistor module; wherein the control end of the switch tube module is used to receive the discharge control signal; the first connection end of the switch tube module is connected to the first connection end of the detection capacitor module; the second connection end of the switch tube module is connected to the second connection end of the detection capacitor module after passing through the discharge resistor module.

[0011] In some embodiments, the liquid level signal output unit includes: a sampling module, an integration module, and a comparison module; wherein the liquid level signal output unit processes the voltage of the detection capacitor module in the current cycle while the detection capacitor module is charging, and outputs the detection signal of the current cycle, including: the sampling module, which is used to sample the voltage on the detection capacitor module in the current cycle while the detection capacitor module is charging, and obtain the voltage of the detection capacitor module; the integration module, which is used to integrate the voltage of the detection capacitor module to obtain an integrated voltage; the comparison module, which is used to compare the integrated voltage with a preset reference voltage to obtain a comparison result, and output the obtained comparison result as the detection signal of the current cycle.

[0012] In some embodiments, the sampling module includes: a sampling resistor module; the integration module includes: an integrator; the comparison module includes: a fourth operational amplifier module, and a reference voltage module; wherein the first connection end of the detection capacitor module is connected to the input end of the integration module after passing through the sampling resistor module; the output end of the integration module is connected to the non-inverting input end of the fourth operational amplifier module; the preset DC power supply is also grounded after passing through the reference voltage module; the output end of the reference voltage module is connected to the inverting input end of the fourth operational amplifier module; the output end of the fourth operational amplifier module is used to output the comparison result.

[0013] Matching the above-mentioned device, the present invention further provides an air-conditioning smoke hood, comprising: the liquid level detection device of the air-conditioning smoke hood described above.

[0014] In order to match the above-mentioned air-conditioning smoke hood, the present invention provides a liquid level detection method for an air-conditioning smoke hood on another aspect, comprising: providing a constant current to the detection capacitor module through the constant current charging unit, so as to charge the detection capacitor module with the constant current; in the current cycle, when it is determined that the voltage of the detection capacitor module has reached a preset maximum voltage threshold, sending a discharge control signal; through the discharge unit, under the control of the discharge control signal, the detection capacitor module is discharged, so that the detection capacitor module can be recharged in the next cycle; through the liquid level signal output unit, in the current cycle, the detection capacitor module is discharged under the control of the discharge control signal. During the charging process of the capacitor module, the voltage of the detection capacitor module is processed and the detection signal of the current cycle is output; thereby, in n cycles within a set time period, the detection signal of n cycles is obtained as the liquid level signal of the condensed water in the water tank; wherein n is a positive integer; according to the liquid level signal, the liquid level detection value of the condensed water in the water tank is determined to realize the detection of the liquid level of the condensed water in the water tank; when the liquid level detection value of the condensed water in the water tank reaches a preset detection value, the preset watering device is controlled to start, so as to water the condensed water in the water tank onto the heat exchanger of the air-conditioning hood to cool the heat exchanger.

[0015] Therefore, the scheme of the present invention forms a liquid level detection capacitor (such as probe capacitor Cx) by setting a pair of electrodes (such as an electrode formed by probe B and electrode sheet A, and another electrode formed by probe A and electrode sheet B) in the water tank of the condensed water of the air-conditioning hood, and sets a liquid level detection circuit composed of a constant current charging unit, a discharge unit and a liquid level signal output unit (such as module 2 circuit), the constant current charging unit provides a constant current based on a DC power supply (such as VCC) to charge the liquid level detection capacitor, and the discharge unit discharges under the control of the MCU after the liquid level detection capacitor is fully charged, the liquid level signal output unit samples and integrates the voltage charged by the liquid level detection capacitor, and then compares it with a preset reference voltage to output a square wave signal, and the MCU determines the liquid level of the condensed water in the water tank based on the square wave signal output by the liquid level signal output unit, thereby realizing the detection of the liquid level of the condensed water in the water tank; thus, the liquid level of the condensed water in the water tank is detected by using a pair of electrodes and a liquid level detection circuit, and the detection accuracy is good.

[0016] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1It is a structural schematic diagram of an embodiment of a liquid level detection device for an air conditioner hood of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the liquid level detection circuit;

[0020] Figure 3 It is a schematic diagram of the arrangement of the liquid level probe;

[0021] Figure 4 It is a schematic diagram of the working waveform of the liquid level detection circuit;

[0022] Figure 5 The figure is a flow chart of an embodiment of a method for detecting a liquid level of an air conditioner hood according to the present invention.

[0023] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0024] 1-water tank; 2-condensed water; 31-electrode sheet A; 32-electrode sheet B; 41-probe A; 42-probe B. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Considering that the air conditioner hood will produce condensed water during operation, it is necessary to detect its liquid level and discharge it. Pouring condensed water on the condenser of the air conditioner can reduce the temperature and improve the energy efficiency of the air conditioner. Therefore, the condensed water can be poured on the condenser according to the size of the liquid level. In related schemes, the liquid level detection of the air conditioner hood is generally carried out using a dedicated liquid level sensor or a liquid level float, which is costly and difficult to control the accuracy of the water level detection. For example: some liquid level detection circuits charge capacitors through resistance and voltage. This scheme is easily affected by voltage fluctuations and temperature, thereby affecting the size of the charging current, and then affecting the accuracy of the liquid level detection.

[0027] Therefore, the solution of the present invention proposes a liquid level detection device for an air-conditioning range hood, specifically a liquid level detection circuit for an air-conditioning range hood, which uses a low-cost water level probe installed in a water tank of condensed water of the air-conditioning range hood, and uses a low-cost liquid level detection circuit to achieve accurate detection of the liquid level, thereby ensuring detection accuracy.

[0028] According to an embodiment of the present invention, a liquid level detection device for an air conditioner hood is provided. Figure 1The structure diagram of an embodiment of the device of the present invention is shown in FIG. The air conditioner hood has a water tank, and the water tank is used to receive and store condensed water generated by the air conditioner hood. Figure 3 In the example shown, a water tank 1 is used to hold condensed water 2; in the solution of the present invention, as Figure 1 As shown, the liquid level detection device of the air conditioner hood comprises: a first electrode (such as Figure 2 In the example shown, one electrode is formed by the probe B and the electrode sheet A), the second electrode (such as Figure 2 In the example shown, another electrode is formed by the probe A and the electrode sheet B), a constant current charging unit (such as Figure 2 In the example shown, the constant current discharge part of the module 1 circuit), the discharge unit (such as Figure 2 In the example shown, the discharge part of the module 1 circuit), the liquid level signal output unit (such as Figure 2 In the example shown, module 2 circuit), and a control unit (such as MCU); the first electrode and the second electrode form a pair of electrodes, and the pair of electrodes are placed in the water tank to form a detection capacitor module (such as probe capacitor Cx) that can detect the liquid level of condensed water in the water tank and output a corresponding voltage; Figure 3 The schematic diagram of the arrangement of the liquid level probe is shown in Figure 2. Figure 3 As shown, in the water tank 1 of the condensed water 2, an electrode sheet 31 (i.e., electrode sheet A), an electrode sheet 32 ​​(i.e., electrode sheet B), a probe 41 (i.e., probe A) and a probe 42 (i.e., probe B) are arranged. A pair of electrode sheets (i.e., electrode sheet A and electrode sheet B) are arranged in a pair of inner walls of the water tank 1. Probe B is arranged on electrode sheet B, and probe A is arranged on electrode sheet A. In this way, probe A and probe B form two ends as detection probe capacitance Cx, which is recorded as probe capacitance Cx. The constant current charging unit, the discharge unit, and the liquid level signal output unit are respectively connected to the detection capacitor; the control unit is respectively connected to the discharge unit and the liquid level signal output unit.

[0029] The constant current charging unit is used to provide a constant current to the detection capacitor module in the current cycle, so as to charge the detection capacitor module with the constant current.

[0030] The control unit is used to send a discharge control signal during the current cycle when the detection capacitor module is charging and it is determined that the voltage of the detection capacitor module has reached a preset maximum voltage threshold, that is, when it is determined that the detection capacitor module is fully charged; wherein the discharge control signal is a signal for controlling the discharge of the discharge unit.

[0031] The discharge unit is used to discharge the detection capacitor module under the control of the discharge control signal in the current cycle, so that the detection capacitor module can be recharged in the next cycle.

[0032] The liquid level signal output unit is used to process the voltage of the detection capacitor module in the current cycle while the detection capacitor module is charging, and output the detection signal of the current cycle to the control unit; thereby, the detection signal of n cycles is obtained in n cycles within a set time period as the liquid level signal of the condensed water in the water tank; wherein n is a positive integer.

[0033] The control unit is used to determine the liquid level detection value of the condensed water in the water tank according to the liquid level signal within a set time period, so as to detect the liquid level of the condensed water in the water tank. Specifically, the control unit uses the set liquid level detection value corresponding to the set liquid level signal that is the same as the liquid level signal in the corresponding relationship as the liquid level detection value of the condensed water in the water tank corresponding to the liquid level signal, so as to detect the liquid level of the condensed water in the water tank.

[0034] The solution of the present invention proposes a liquid level detection circuit for an air conditioner hood, which utilizes a low-cost water level probe installed in a water tank of condensed water of the air conditioner hood, and realizes accurate detection of the liquid level through a low-cost liquid level detection circuit with high reliability.

[0035] In some embodiments, the air conditioning hood further comprises a heat exchanger, and a preset watering device is provided between the heat exchanger and the water tank.

[0036] The control unit is further configured to control a preset irrigation device to start when the liquid level detection value of the condensed water in the water tank reaches a preset detection value, so as to irrigate the condensed water in the water tank onto the heat exchanger of the air conditioner hood to cool the heat exchanger. The preset irrigation device may be a water pump device disposed between the water tank and the heat exchanger of the air conditioner hood.

[0037] In the scheme of the present invention, by designing a liquid level detection circuit, the liquid level of condensed water can be detected at a constant current, which can improve the accuracy of detecting the liquid level of condensed water in the air-conditioning range hood; at the same time, whether to pour the condensed water onto the condenser is selected according to the size of the liquid level, thereby improving energy efficiency, with low cost and high reliability.

[0038] In some embodiments, the constant current charging unit includes: a voltage input module (such as a voltage divider module composed of resistor R3 and resistor R4), a voltage follower module (such as a two-stage voltage follower composed of operational amplifier U4-A and operational amplifier U3-A), a constant voltage module (such as an instrument amplifier composed of operational amplifier U6, resistor RF and resistor RG), and a charging module (such as resistor R6).

[0039] The constant current charging unit provides a constant current to the detection capacitor module in a current cycle, so as to charge the detection capacitor module with the constant current, including:

[0040] The voltage input module is used to perform voltage division based on a preset DC power supply to obtain a divided voltage (such as voltage V1), and input the obtained divided voltage to the voltage follower module.

[0041] The voltage following module is used to perform voltage following on the divided voltage to obtain a following voltage (such as voltage V3).

[0042] The constant voltage module is used to perform constant voltage operation on the following voltage to obtain a constant voltage (such as voltage V3-V4).

[0043] The charging module is used to generate a constant current based on the constant voltage, and use the constant current to charge the detection capacitor module.

[0044] Figure 2 It is a structural diagram of the liquid level detection circuit. Figure 2 As shown, the liquid level detection circuit provided by the solution of the present invention is a condensed water constant current liquid level detection circuit. Figure 2 The liquid level detection circuit shown includes: module 1 circuit and module 2 circuit, which form a condensed water constant current liquid level detection circuit. The condensed water constant current liquid level detection circuit is designed to charge the probe capacitor Cx, thereby realizing the detection of the liquid level. Compared with the current scheme of constant voltage source + resistor in the related scheme, the condensed water constant current liquid level detection circuit has higher accuracy and a low temperature drift coefficient of the rectification circuit. By real-time monitoring of the liquid level height, different logic processing is realized, that is, liquid level detection is realized and energy efficiency is improved.

[0045] In some embodiments, the voltage input module includes: a first voltage-dividing resistor module (such as resistor R3), a second voltage-dividing resistor module (such as resistor R4); the voltage follower module includes: a first operational amplifier module (such as operational amplifier U4-A); the constant voltage module includes: a second operational amplifier module (such as operational amplifier U6), a third voltage-dividing resistor module (such as resistor R7), and a fourth voltage-dividing resistor module (such as resistor RG); the charging module includes: a current-limiting resistor module (such as resistor R6).

[0046] Wherein, a preset DC power supply (such as power supply VCC) is grounded after passing through the first voltage-dividing resistor module and the second voltage-dividing resistor module; the common end of the first voltage-dividing resistor module and the second voltage-dividing resistor module is connected to the in-phase input end of the first operational amplifier module; the inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module; the output end of the first operational amplifier module is connected to the in-phase input end of the second operational amplifier module; the output end of the first operational amplifier module is connected to the first connection end of the detection capacitor module after passing through the current-limiting resistor module; the output end of the first operational amplifier module is also connected to the output end of the second operational amplifier module; the second connection end of the detection capacitor module is grounded. The inverting input end of the second operational amplifier module is connected to the first connection end of the detection capacitor module; the output end of the second operational amplifier module is also connected to the preset reference voltage connection end after passing through the third voltage-dividing resistor module and the fourth voltage-dividing resistor module.

[0047] In the scheme of the present invention, the constant current charging unit is formed by a voltage input module, a voltage following module, a constant voltage module, and a charging module, thereby forming a liquid level detection circuit, which can detect the liquid level of condensed water at a constant current, thereby improving the accuracy of detecting the liquid level of condensed water in the air-conditioning range hood; at the same time, whether to pour the condensed water onto the condenser is selected according to the size of the liquid level, thereby improving energy efficiency, with low cost and high reliability.

[0048] In some embodiments, the voltage follower module further includes: a third operational amplifier module (such as an operational amplifier U3-A). The output end of the first operational amplifier module is connected to the non-inverting input end of the third operational amplifier module; the inverting input end of the third operational amplifier module is connected to the output end of the second operational amplifier module. The output end of the third operational amplifier module is connected to the non-inverting input end of the second operational amplifier module; the output end of the third operational amplifier module is connected to the first connection end of the detection capacitor module after passing through the current limiting resistor module; the output end of the third operational amplifier module is also connected to the output end of the second operational amplifier module.

[0049] See also Figure 2In the example shown, the DC power supply VCC is grounded after passing through the resistor R3 and the resistor R4, and the common end of the resistor R3 and the resistor R4 outputs the voltage V1 to the non-inverting input end of the operational amplifier U4-A, and the inverting input end of the operational amplifier U4-A is connected to the output end of the operational amplifier U4-A. The output end of the operational amplifier U4-A outputs the voltage V2 to the non-inverting input end of the operational amplifier U3-A, and the inverting input end of the operational amplifier U3-A is connected to the output end of the operational amplifier U6. The output end of the operational amplifier U6 outputs the voltage V5, and the voltage V5 is connected to the terminal VREF (i.e., the reference voltage connection end) after passing through the resistor RF and the resistor RG. The terminal VREF is connected to the pin 4 of the operational amplifier U6, and the common end of the resistor RF and the resistor RG is connected to the pin 5 of the operational amplifier U6. Both the pin 4 and the pin 5 of the operational amplifier U6 are feedback pins. The output end of the operational amplifier U3-A outputs the voltage V3 to the non-inverting input end of the operational amplifier U6, and the inverting input end of the operational amplifier U6 is grounded after passing through the probe capacitor Cx. The voltage V3 is grounded after passing through the resistor R6 and the probe capacitor Cx.

[0050] In the scheme of the present invention, a single-stage voltage follower is formed by the third operational amplifier module as a voltage follower module, and then the constant current charging unit is formed by the voltage input module, the voltage follower module, the constant voltage module, and the charging module, and finally a liquid level detection circuit is formed, which can detect the liquid level of condensed water at a constant current, and can improve the accuracy of detecting the liquid level of condensed water in the air-conditioning range hood; at the same time, it is selected whether to pour the condensed water onto the condenser according to the size of the liquid level, which plays a role in improving energy efficiency, with low cost and high reliability.

[0051] In some embodiments, the discharge unit includes: a switch tube module (such as transistor Q1), and a discharge resistor module (such as resistor R7). The control end of the switch tube module (such as the base of the transistor Q1) is used to receive the discharge control signal; the first connection end of the switch tube module (such as the collector of the transistor Q1) is connected to the first connection end of the detection capacitor module; the second connection end of the switch tube module (such as the emitter of the transistor Q1) is connected to the second connection end of the detection capacitor module after passing through the discharge resistor module.

[0052] exist Figure 2In the example shown, the module 1 circuit includes: resistor R3, resistor R4, resistor R6, resistor R7, resistor RF, resistor RG, operational amplifier U3-A, operational amplifier U4-A, operational amplifier U6, and transistor Q1. The output terminal of the operational amplifier U3-A outputs the voltage V3 to the non-inverting input terminal of the operational amplifier U6, and the inverting input terminal of the operational amplifier U6 is connected to the collector of the transistor Q1. The common terminal of the resistor R6 and the probe capacitor Cx is connected to the collector of the transistor Q1, and the voltage of the collector of the transistor Q1 is the voltage V4. The base of the transistor Q1 is connected to the terminal SW (i.e., the control terminal). The emitter of the transistor Q1 is grounded after passing through the resistor R7.

[0053] The module 1 circuit is used to output a constant current, which charges the probe capacitor Cx. At the same time, in order to ensure that the probe capacitor Cx can be continuously charged and discharged, the transistor Q1 and the resistor R7 are designed to discharge the probe capacitor Cx.

[0054] In the scheme of the present invention, by combining the constant current charging unit and the discharge power supply, a liquid level detection circuit is finally formed, which can detect the liquid level of condensed water at a constant current, thereby improving the accuracy of detecting the liquid level of condensed water in the air-conditioning range hood; at the same time, whether to pour the condensed water onto the condenser is selected according to the size of the liquid level, thereby improving energy efficiency, with low cost and high reliability.

[0055] In some embodiments, the liquid level signal output unit includes: a sampling module (such as resistor R1), an integration module (such as an integrator composed of an operational amplifier U1-A and a capacitor C1), and a comparison module (such as a comparator composed of an operational amplifier U2-A, a resistor R2 and a resistor R5).

[0056] The liquid level signal output unit processes the voltage of the detection capacitor module in the current cycle and outputs the detection signal in the current cycle during the charging process of the detection capacitor module, including:

[0057] The sampling module is used to sample the voltage on the detection capacitor module during the charging process of the detection capacitor module in the current cycle to obtain the voltage of the detection capacitor module.

[0058] The integration module is used to integrate the voltage of the detection capacitor module to obtain an integrated voltage.

[0059] The comparison module is used to compare the integrated voltage with a preset reference voltage to obtain a comparison result, and output the obtained comparison result as a detection signal in the current cycle.

[0060] See also Figure 3In the example shown, the circuit of module 2 detects the voltage on the probe capacitor Cx, integrates it through the integrator formed by the operational amplifier U1-A and the capacitor C1, and then compares it with the preset voltage at the inverting input terminal of the comparator formed by the operational amplifier U2-A. The comparator formed by the operational amplifier U2-A outputs a PWM waveform with a variable frequency (as a liquid level detection signal LIQUID-LEVEL). The frequency of the PWM waveform output by the comparator formed by the operational amplifier U2-A is affected by the liquid level height of the condensed water 2 in the water tank 1. The higher the frequency of the PWM waveform, the smaller the liquid level of the condensed water 2 in the water tank 1.

[0061] In the scheme of the present invention, by combining the constant current charging unit, the discharge unit and the liquid level signal output unit, a liquid level detection circuit is finally formed, which can detect the liquid level of condensed water at a constant current, thereby improving the accuracy of detecting the liquid level of condensed water in the air-conditioning range hood; at the same time, whether to pour the condensed water onto the condenser is selected according to the size of the liquid level, thereby improving energy efficiency, with low cost and high reliability.

[0062] In some embodiments, the sampling module includes: a sampling resistor module (such as resistor R1); the integration module includes: an integrator (such as an integrator composed of an operational amplifier U1-A and a capacitor C1); the comparison module includes: a fourth operational amplifier module (such as operational amplifier U2-A), and a reference voltage module (such as resistor R5 and resistor R2).

[0063] Among them, the first connection end of the detection capacitor module is connected to the input end of the integration module (i.e., the non-inverting input end of the operational amplifier U1-A) after passing through the sampling resistor module; the output end of the integration module (i.e., the output end of the operational amplifier U1-A) is connected to the non-inverting input end of the fourth operational amplifier module. The preset DC power supply is also grounded after passing through the reference voltage module; the output end of the reference voltage module (such as the common end of the resistor R5 and the resistor R2) is connected to the inverting input end of the fourth operational amplifier module; the output end of the fourth operational amplifier module is used to output the comparison result.

[0064] See also Figure 2In the example shown, the DC power supply VCC is also connected to the ground after passing through the resistor R5 and the resistor R2, and the common end of the resistor R5 and the resistor R2 is connected to the inverting input end of the operational amplifier U2-A. The common end of the resistor R6 and the probe capacitor Cx is connected to the non-inverting input end of the operational amplifier U1-A after passing through the resistor R1, and the inverting input end of the operational amplifier U1-A is grounded. The non-inverting input end of the operational amplifier U1-A is also connected to the output end of the operational amplifier U1-A after passing through the capacitor C1. The output end of the operational amplifier U1-A outputs the voltage V6 to the non-inverting input end of the operational amplifier U2-A, and the output end of the operational amplifier U2-A is connected to the terminal LIQUID-LEVEL (i.e., the liquid level output end).

[0065] In the related solutions, the dedicated liquid level sensor and float are purchased components, and a special sensor detection circuit is required to realize liquid level detection. However, the solution patent application of the present invention realizes liquid level detection only through a liquid level probe and four operational amplifiers, which can reduce costs.

[0066] In the scheme of the present invention, a liquid level detection circuit is finally formed by a liquid level signal output unit formed by a sampling module, an integration module, and a comparison module, and then combined with the constant current charging unit, the discharge unit, and the liquid level signal output unit. The liquid level of condensed water can be detected at a constant current, and the accuracy of detecting the liquid level of condensed water in the air-conditioning range hood can be improved. At the same time, whether to pour the condensed water onto the condenser can be selected according to the size of the liquid level, thereby improving energy efficiency, with low cost and high reliability.

[0067] In some embodiments, the integration module includes: a fifth operational amplifier module (such as operational amplifier U1-A), and a capacitor module (such as capacitor C1). The capacitor module is connected between the non-inverting input terminal of the fifth operational amplifier module and the input terminal of the fifth operational amplifier module; the non-inverting input terminal of the fifth operational amplifier module serves as the input terminal of the integration module; the inverting input terminal of the fifth operational amplifier module is grounded; and the output terminal of the fifth operational amplifier module serves as the output terminal of the integration module.

[0068] See also Figure 2 In the example shown, the module 2 circuit includes: a resistor R1, a resistor R2, a resistor R5, a capacitor C1, an operational amplifier U1-A, an operational amplifier U2-A, and a capacitor C1.

[0069] In the module 2 circuit, the operational amplifier U1-A and the capacitor C1 form an integrator, and the operational amplifier U2-A forms a comparator; when the voltage at the positive input terminal of the operational amplifier U2-A is higher than the voltage at the reverse input terminal of the operational amplifier U2-A, the operational amplifier U2-A outputs a high level, otherwise the operational amplifier U2-A outputs a low level. At the same time, in order to continuously charge and discharge the probe capacitor Cx, a discharge circuit (i.e., a circuit composed of a transistor Q1 and a resistor R7) is connected in parallel at the probe capacitor Cx, and the discharge circuit is controlled by the control terminal SW. When the control terminal SW is at a high level, the transistor Q1 is turned on, and the probe capacitor Cx is discharged through the resistor R7. On the contrary, when the control terminal SW is at a low level, the transistor Q1 is turned off, and the probe capacitor Cx continues to be charged; wherein, the probe capacitor Cx needs to be discharged when it is fully charged.

[0070] See also Figure 2 and Figure 3 In the example shown, the working principle of the liquid level detection circuit of the air conditioner hood is as follows: the voltage V1 input to the positive input terminal (i.e., the in-phase input terminal) of the voltage follower formed by the operational amplifier U4-A satisfies V1=V2=VCC*R4 / (R3+R4), and similarly V1=V2=V5. The operational amplifier U6 constitutes an instrumentation amplifier, and the gain G of the instrumentation amplifier satisfies G=1+RF / RG. The input voltage of the instrumentation amplifier is the voltage V across the resistor R6. R6 , V R6 =V3-V4, from the gain G, we know that V R6 =V5 / G. Since the resistor R6 is connected in series with the liquid level sensor (i.e., the probe capacitor Cx), the current of the resistor R6 is constant at I R6 = Current I of probe capacitance Cx Cx And satisfy I R6 =I Cx =V R6 / R6={VCC*R4 / (R3+R4)} / (G*R6), when the constant current I Cx When charging the probe capacitor Cx, the voltage of the probe capacitor Cx rises in a triangular shape. After passing the current of the module 2 circuit, LIQUID-LEVEL outputs a square wave with the same phase. The signal is connected to the MCU. The MCU detects the frequency of the square wave and determines the height of the liquid level according to the frequency of the square wave. The higher the frequency of the square wave, the lower the liquid level. Among them, an instrument amplifier is set to accurately detect the voltage across the resistor R6 by differential input, which has higher accuracy and better common mode rejection ratio than the operational amplifier.

[0071] When the liquid level of condensed water in the water tank 1 of the air conditioner hood increases, the capacitance value of the probe capacitor Cx increases, and the charging speed of the probe capacitor Cx slows down, then the frequency of LIQUID-LEVEL decreases, otherwise the frequency increases, so the liquid level can be judged by the frequency of LIQUID-LEVEL. Figure 3 In the example shown, probe A, probe B and the condensed water in the water tank 1 are regarded as a whole, which is an equivalent capacitor. According to the capacitance formula, the higher the liquid level, the larger the capacitance. If the capacitance charging current remains unchanged, the capacitance value of the probe capacitor Cx increases, and the charging speed of the probe capacitor Cx slows down. Figure 2 In the example shown, the frequency of the comparator output LIQUID-LEVEL will also change. The higher the frequency, the smaller the liquid level. Therefore, the liquid level height can be determined by the frequency. Figure 4 The working waveform diagram of the liquid level detection circuit is shown in Figure 2. Figure 4 When the liquid level is higher than a certain threshold, a device (such as a water pump) is used to pour condensed water onto the condenser to reduce the temperature and improve energy efficiency.

[0072] In the scheme of the present invention, by designing a liquid level detection circuit, the liquid level of condensed water can be detected at a constant current, which can improve the accuracy of detecting the liquid level of condensed water in the air-conditioning range hood; at the same time, whether to pour the condensed water onto the condenser is selected according to the size of the liquid level, thereby improving energy efficiency, with low cost and high reliability.

[0073] According to the technical solution of the present invention, a pair of electrodes (such as one electrode formed by probe B and electrode sheet A, and another electrode formed by probe A and electrode sheet B) is arranged in a water tank of condensed water of an air conditioner hood to form a liquid level detection capacitor (such as probe capacitor Cx), and a liquid level detection circuit composed of a constant current charging unit, a discharge unit and a liquid level signal output unit (such as module 2 circuit) is arranged, the constant current charging unit provides a constant current based on a DC power supply (such as VCC) to charge the liquid level detection capacitor, the discharge unit discharges under the control of an MCU after the liquid level detection capacitor is fully charged, the liquid level signal output unit samples and integrates the voltage charged by the liquid level detection capacitor, and then compares it with a preset reference voltage to output a square wave signal, the MCU determines the liquid level of the condensed water in the water tank based on the square wave signal output by the liquid level signal output unit, and realizes the detection of the liquid level of the condensed water in the water tank; thus, the liquid level of the condensed water in the water tank is detected by using a pair of electrodes and a liquid level detection circuit, and the detection accuracy is good.

[0074] According to an embodiment of the present invention, an air-conditioning hood corresponding to the liquid level detection device of the air-conditioning hood is also provided. The air-conditioning hood may include: the liquid level detection device of the air-conditioning hood described above.

[0075] Since the processing and functions implemented by the air-conditioning hood of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0076] According to an embodiment of the present invention, a liquid level detection method for an air conditioner hood hood is also provided, such as Figure 5 The flow chart of an embodiment of the method of the present invention is shown in FIG. The liquid level detection method of the air conditioner hood may include: steps S110 to S160.

[0077] In step S110, the constant current charging unit provides a constant current to the detection capacitor module in the current cycle, so as to charge the detection capacitor module with the constant current.

[0078] At step S120, in the current cycle, during the charging process of the detection capacitor module, when it is determined that the voltage of the detection capacitor module has reached a preset maximum voltage threshold, that is, when it is determined that the detection capacitor module is fully charged, a discharge control signal is issued; wherein the discharge control signal is a signal for controlling the discharge of the discharge unit.

[0079] At step S130, the detection capacitor module is discharged by the discharge unit under the control of the discharge control signal in the current cycle, so that the detection capacitor module can be recharged in the next cycle.

[0080] At step S140, through the liquid level signal output unit, in the current cycle, while the detection capacitor module is charging, the voltage of the detection capacitor module is processed and the detection signal of the current cycle is output; thereby, in n cycles within a set time period, the detection signal of n cycles is obtained as the liquid level signal of the condensed water in the water tank; wherein n is a positive integer.

[0081] At step S150, within a set time period, according to the liquid level signal, the liquid level detection value of the condensed water in the water tank is determined to detect the liquid level of the condensed water in the water tank. Specifically, according to the correspondence between the set liquid level signal and the set liquid level detection value, the set liquid level detection value corresponding to the set liquid level signal that is the same as the liquid level signal in the correspondence is used as the liquid level detection value of the condensed water in the water tank corresponding to the liquid level signal to detect the liquid level of the condensed water in the water tank.

[0082] In step S160, when the liquid level detection value of the condensed water in the water tank reaches a preset detection value, a preset irrigation device is controlled to start so as to irrigate the condensed water in the water tank onto the heat exchanger of the air conditioner hood to cool the heat exchanger. The preset irrigation device may be a water pump device disposed between the water tank and the heat exchanger of the air conditioner hood.

[0083] like Figure 2 The liquid level detection circuit shown includes: module 1 circuit and module 2 circuit, which form a condensed water constant current liquid level detection circuit. The condensed water constant current liquid level detection circuit is designed to charge the probe capacitor Cx, thereby realizing liquid level detection.

[0084] See also Figure 2 In the example shown, the module 1 circuit includes: resistor R3, resistor R4, resistor R6, resistor R7, resistor RF, resistor RG, operational amplifier U3-A, operational amplifier U4-A, operational amplifier U6, and transistor Q1. The module 2 circuit includes: resistor R1, resistor R2, resistor R5, capacitor C1, operational amplifier U1-A, operational amplifier U2-A, and capacitor C1.

[0085] The module 1 circuit is used to output a constant current, which charges the probe capacitor Cx. At the same time, in order to ensure that the probe capacitor Cx can be continuously charged and discharged, the transistor Q1 and the resistor R7 are designed to discharge the probe capacitor Cx.

[0086] In the circuit of module 1, the DC power supply VCC is grounded after passing through the resistor R3 and the resistor R4, and the common end of the resistor R3 and the resistor R4 outputs the voltage V1 to the non-inverting input end of the operational amplifier U4-A, and the inverting input end of the operational amplifier U4-A is connected to the output end of the operational amplifier U4-A. The output end of the operational amplifier U4-A outputs the voltage V2 to the non-inverting input end of the operational amplifier U3-A, and the inverting input end of the operational amplifier U3-A is connected to the output end of the operational amplifier U6. The output end of the operational amplifier U6 outputs the voltage V5, and the voltage V5 is connected to the terminal VREF (i.e., the reference voltage connection end) after passing through the resistor RF and the resistor RG. The terminal VREF is connected to the pin 4 of the operational amplifier U6, and the common end of the resistor RF and the resistor RG is connected to the pin 5 of the operational amplifier U6. The output end of the operational amplifier U3-A outputs the voltage V3 to the non-inverting input end of the operational amplifier U6, and the inverting input end of the operational amplifier U6 is grounded after passing through the probe capacitor Cx. The voltage V3 is grounded after passing through the resistor R6 and the probe capacitor Cx. The output terminal of the operational amplifier U3-A outputs the voltage V3 to the non-inverting input terminal of the operational amplifier U6, and the inverting input terminal of the operational amplifier U6 is connected to the collector of the transistor Q1. The common terminal of the resistor R6 and the probe capacitor Cx is connected to the collector of the transistor Q1, and the voltage of the collector of the transistor Q1 is the voltage V4. The base of the transistor Q1 is connected to the terminal SW (i.e., the control terminal). The emitter of the transistor Q1 is grounded after passing through the resistor R7.

[0087] The circuit of module 2 detects the voltage on the probe capacitor Cx, integrates it through the integrator formed by the operational amplifier U1-A and the capacitor C1, and then compares it with the preset voltage at the inverting input terminal of the comparator formed by the operational amplifier U2-A. The comparator formed by the operational amplifier U2-A outputs a PWM waveform with variable frequency (as a liquid level detection signal LIQUID-LEVEL). The frequency of the PWM waveform output by the comparator formed by the operational amplifier U2-A is affected by the liquid level height of the condensed water 2 in the water tank 1. The higher the frequency of the PWM waveform, the smaller the liquid level of the condensed water 2 in the water tank 1.

[0088] The DC power supply VCC is also connected to the ground through the resistor R5 and the resistor R2. The common end of the resistor R5 and the resistor R2 is connected to the inverting input end of the operational amplifier U2-A. The common end of the resistor R6 and the probe capacitor Cx is connected to the non-inverting input end of the operational amplifier U1-A through the resistor R1. The inverting input end of the operational amplifier U1-A is grounded. The non-inverting input end of the operational amplifier U1-A is also connected to the output end of the operational amplifier U1-A through the capacitor C1. The output end of the operational amplifier U1-A outputs the voltage V6 to the non-inverting input end of the operational amplifier U2-A. The output end of the operational amplifier U2-A is connected to the terminal LIQUID-LEVEL (i.e., the liquid level output end).

[0089] In the module 2 circuit, the operational amplifier U1-A and the capacitor C1 form an integrator, and the operational amplifier U2-A forms a comparator; when the voltage at the positive input terminal of the operational amplifier U2-A is higher than the voltage at the reverse input terminal of the operational amplifier U2-A, the operational amplifier U2-A outputs a high level, otherwise the operational amplifier U2-A outputs a low level. At the same time, in order to continuously charge and discharge the probe capacitor Cx, a discharge circuit (i.e., a circuit composed of transistor Q1 and resistor R7) is connected in parallel at the probe capacitor Cx, and the discharge circuit is controlled by the control terminal SW. When the control terminal SW is at a high level, the transistor Q1 is turned on, and the probe capacitor Cx is discharged through the resistor R7. On the contrary, when the control terminal SW is at a low level, the transistor Q1 is turned off, and the probe capacitor Cx continues to be charged.

[0090] See also Figure 2 and Figure 3 In the example shown, the working principle of the liquid level detection circuit of the air conditioner hood is as follows: the voltage V1 input to the positive input terminal (i.e., the in-phase input terminal) of the voltage follower formed by the operational amplifier U4-A satisfies V1=V2=VCC*R4 / (R3+R4), and similarly V1=V2=V5. The operational amplifier U6 constitutes an instrumentation amplifier, and the gain G of the instrumentation amplifier satisfies G=1+RF / RG. The input voltage of the instrumentation amplifier is the voltage V across the resistor R6. R6 , V R6 =V3-V4, from the gain G, we know that V R6 =V5 / G. Since the resistor R6 is connected in series with the liquid level sensor (i.e., the probe capacitor Cx), the current of the resistor R6 is constant at I R6 = Current I of probe capacitance Cx Cx And satisfy I R6 =I Cx =V R6 / R6={VCC*R4 / (R3+R4)} / (G*R6), when the constant current I Cx When charging the probe capacitor Cx, the voltage of the probe capacitor Cx rises in a triangular shape. After the current passes through the circuit of module 2, LIQUID-LEVEL outputs a square wave with the same phase. The signal is connected to the MCU. The MCU detects the frequency of the square wave and determines the height of the liquid level based on the frequency of the square wave. The higher the frequency of the square wave, the lower the liquid level.

[0091] When the liquid level of condensed water in the water tank 1 of the air conditioner hood increases, the capacitance value of the probe capacitor Cx increases, and the charging speed of the probe capacitor Cx slows down, then the frequency of LIQUID-LEVEL decreases, otherwise the frequency increases, so the liquid level can be judged by the frequency of LIQUID-LEVEL. Figure 3In the example shown, probe A, probe B and the condensed water in the water tank 1 are regarded as a whole, which is an equivalent capacitor. According to the capacitance formula, the higher the liquid level, the larger the capacitance. If the capacitance charging current remains unchanged, the capacitance value of the probe capacitor Cx increases, and the charging speed of the probe capacitor Cx slows down. Figure 2 In the example shown, the frequency of the comparator output LIQUID-LEVEL will also change. The higher the frequency, the smaller the liquid level. Therefore, the liquid level height can be determined by the frequency. Figure 4 The working waveform diagram of the liquid level detection circuit is shown in Figure 2. Figure 4 When the liquid level is higher than a certain threshold, a device (such as a water pump) is used to pour condensed water onto the condenser to reduce the temperature and improve energy efficiency.

[0092] In the scheme of the present invention, by designing a liquid level detection circuit, the liquid level of condensed water can be detected at a constant current, which can improve the accuracy of detecting the liquid level of condensed water in the air conditioner hood; at the same time, according to the size of the liquid level, it is selected whether to pour the condensed water onto the condenser, which plays a role in improving energy efficiency, low cost and high reliability. A low-cost water level probe is installed in the water tank of the condensed water in the air conditioner hood, and a low-cost liquid level detection circuit is used to achieve accurate detection of the liquid level, which has high reliability.

[0093] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned air-conditioning smoke hood, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0094] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0095] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A liquid level detection device for an air conditioner hood, characterized in that: The air conditioner hood has a water tank, which is used to receive and store condensed water generated by the air conditioner hood; the liquid level detection device of the air conditioner hood includes: a first electrode, a second electrode, a constant current charging unit, a discharge unit, a liquid level signal output unit, and a control unit; the first electrode and the second electrode form a pair of electrodes, and the pair of electrodes are placed in the water tank to form a detection capacitor module that can detect the liquid level of condensed water in the water tank and output a corresponding voltage; wherein, The constant current charging unit is used to provide a constant current to the detection capacitor module, so as to charge the detection capacitor module with the constant current; The control unit is used to send a discharge control signal when it is determined that the voltage of the detection capacitor module has reached a preset maximum voltage threshold in the current cycle; The discharge unit is used to discharge the detection capacitor module under the control of the discharge control signal, so that the detection capacitor module can be recharged in the next cycle; The liquid level signal output unit is used to process the voltage of the detection capacitor module in the current cycle and output the detection signal in the current cycle during the charging of the detection capacitor module; thereby, the detection signal in n cycles within the set time period is obtained as the liquid level signal of the condensed water in the water tank; wherein n is a positive integer; the liquid level signal output unit includes: a sampling module, an integration module, and a comparison module; wherein, the liquid level signal output unit processes the voltage of the detection capacitor module in the current cycle and outputs the detection signal in the current cycle during the charging of the detection capacitor module, including: the sampling module is used to sample the voltage on the detection capacitor module in the current cycle and obtain the voltage of the detection capacitor module during the charging of the detection capacitor module; the integration module is used to integrate the voltage of the detection capacitor module and obtain the integrated voltage; the comparison module is used to compare the integrated voltage with a preset reference voltage to obtain a comparison result, and output the obtained comparison result as the detection signal in the current cycle; The control unit is used to determine the liquid level detection value of the condensed water in the water tank according to the liquid level signal, so as to detect the liquid level of the condensed water in the water tank; The constant current charging unit provides a constant current based on a DC power supply to charge the detection capacitor module. After the detection capacitor module is fully charged, the discharge unit discharges it under the control of the MCU. The liquid level signal output unit samples and integrates the voltage charged by the detection capacitor module and then compares it with a preset reference voltage to output a square wave signal. The MCU determines the liquid level of condensed water in the water tank based on the square wave signal output by the liquid level signal output unit.

2. The liquid level detection device for the air conditioner hood according to claim 1, characterized in that: The air conditioning hood also has a heat exchanger, and a preset irrigation device is provided between the heat exchanger and the water tank; The control unit is also used to control a preset watering device to start when the liquid level detection value of the condensed water in the water tank reaches a preset detection value, so as to pour the condensed water in the water tank onto the heat exchanger of the air-conditioning hood to cool the heat exchanger.

3. The liquid level detection device for an air conditioner hood according to claim 1, characterized in that: The constant current charging unit includes: a voltage input module, a voltage following module, a constant voltage module, and a charging module; wherein, The constant current charging unit provides a constant current to the detection capacitor module in a current cycle, so as to charge the detection capacitor module with the constant current, including: The voltage input module is used to divide the voltage based on a preset DC power supply to obtain a divided voltage; The voltage following module is used to perform voltage following on the divided voltage to obtain a following voltage; The constant voltage module is used to perform constant voltage operation on the following voltage to obtain a constant voltage; The charging module is used to generate a constant current based on the constant voltage, and use the constant current to charge the detection capacitor module.

4. The liquid level detection device for the air conditioner hood according to claim 3, characterized in that: The voltage input module includes: a first voltage-dividing resistor module and a second voltage-dividing resistor module; the voltage follower module includes: a first operational amplifier module; the constant voltage module includes: a second operational amplifier module, a third voltage-dividing resistor module, and a fourth voltage-dividing resistor module; the charging module includes: a current-limiting resistor module; wherein, A preset DC power supply is grounded after passing through the first voltage-dividing resistor module and the second voltage-dividing resistor module; a common end of the first voltage-dividing resistor module and the second voltage-dividing resistor module is connected to the in-phase input end of the first operational amplifier module; an inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module; an output end of the first operational amplifier module is connected to the in-phase input end of the second operational amplifier module; an output end of the first operational amplifier module is connected to a first connection end of the detection capacitor module after passing through the current-limiting resistor module; an output end of the first operational amplifier module is also connected to an output end of the second operational amplifier module; a second connection end of the detection capacitor module is grounded; The inverting input terminal of the second operational amplifier module is connected to the first connection terminal of the detection capacitor module; the output terminal of the second operational amplifier module is connected to the preset reference voltage connection terminal after passing through the third voltage-dividing resistor module and the fourth voltage-dividing resistor module.

5. The liquid level detection device for the air conditioner hood according to claim 4, characterized in that: The voltage follower module further includes: a third operational amplifier module; wherein, The output end of the first operational amplifier module is connected to the non-inverting input end of the third operational amplifier module; the inverting input end of the third operational amplifier module is connected to the output end of the second operational amplifier module; The output end of the third operational amplifier module is connected to the in-phase input end of the second operational amplifier module; the output end of the third operational amplifier module is connected to the first connection end of the detection capacitor module after passing through the current limiting resistor module; the output end of the third operational amplifier module is also connected to the output end of the second operational amplifier module.

6. The liquid level detection device for an air conditioner hood according to claim 1, characterized in that: The discharge unit includes: a switch tube module and a discharge resistor module; wherein, The control end of the switch tube module is used to receive the discharge control signal; the first connection end of the switch tube module is connected to the first connection end of the detection capacitor module; the second connection end of the switch tube module is connected to the second connection end of the detection capacitor module after passing through the discharge resistor module.

7. The liquid level detection device for an air conditioner hood according to claim 1, characterized in that: The sampling module includes: a sampling resistor module; the integration module includes: an integrator; the comparison module includes: a fourth operational amplifier module and a reference voltage module; wherein, The first connection end of the detection capacitor module is connected to the input end of the integration module after passing through the sampling resistor module; the output end of the integration module is connected to the non-inverting input end of the fourth operational amplifier module; The preset DC power supply is also grounded after passing through the reference voltage module; the output end of the reference voltage module is connected to the inverting input end of the fourth operational amplifier module; the output end of the fourth operational amplifier module is used to output the comparison result.

8. An air conditioner hood, characterized in that: include: A liquid level detection device for an air conditioning hood as claimed in any one of claims 1 to 7.

9. A liquid level detection method for an air conditioner hood as claimed in claim 8, characterized in that: include: Providing a constant current to the detection capacitor module through the constant current charging unit, so as to charge the detection capacitor module with the constant current; In the current cycle, when it is determined that the voltage of the detection capacitor module has reached a preset maximum voltage threshold, a discharge control signal is issued; Through the discharge unit, under the control of the discharge control signal, the detection capacitor module is discharged, so that the detection capacitor module can be recharged in the next cycle; Through the liquid level signal output unit, in the current cycle, during the charging process of the detection capacitor module, the voltage of the detection capacitor module is processed to output the detection signal of the current cycle; thereby, in n cycles within a set time period, the detection signal of n cycles is obtained as the liquid level signal of the condensed water in the water tank; wherein n is a positive integer; Determining a liquid level detection value of the condensed water in the water tank according to the liquid level signal, so as to detect the liquid level of the condensed water in the water tank; When the liquid level detection value of the condensed water in the water tank reaches a preset detection value, the preset irrigation device is controlled to start so as to pour the condensed water in the water tank onto the heat exchanger of the air conditioner hood to cool the heat exchanger.

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