A material shortage detection sensor, dishwasher and material shortage detection method

Abstract

The embodiments of the present invention disclose a material shortage detection sensor, a dishwasher, and a material shortage detection method, which relate to the field of electrical appliance technology. The sensor comprises: a reference signal unit, a detection signal unit, and a central processing unit; the reference signal unit and the detection signal unit are RC oscillation circuits, and the detection capacitor element of the detection signal unit comprises a detection electrode; the central processing unit comprises: a pulse generator and a signal comparator; wherein the reference signal unit and the detection signal unit are connected to the pulse generator and the signal comparator, respectively; the pulse generator is used to send a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit; the signal comparator is used to collect the voltage amplitude of the reference signal unit and the detection signal unit in the charging or discharging state, and output an indication signal for indicating whether there is material shortage based on the time it takes for the voltage amplitude to rise or fall to the reference voltage value. The present invention is applicable to material detection scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical appliances, and in particular to a material shortage detection sensor, a dishwasher and a material shortage detection method. Background Art

[0002] During the dishwashing process, a peristaltic pump is usually used to pump the detergent in the cleaning liquid bottle into the cleaning water tank. After mixing with water, the detergent is pumped into the cleaning chamber through the cleaning pump for cleaning. After each basket of dishes is washed, the concentration of the detergent in the cleaning water tank will be partially consumed. The peristaltic pump is needed to pump the detergent in the cleaning liquid bottle into the cleaning water tank again to ensure the cleaning effect.

[0003] However, the cleaning liquid in the cleaning liquid bottle may be consumed or bubbles may form in the pump tube. When the cleaning liquid cannot be pumped into the cleaning water tank in a timely and sufficient manner, the cleaning effect will be affected. To solve this problem, a material shortage sensor is installed on the pump tube of the peristaltic pump to monitor whether there is liquid in the pump tube.

[0004] Currently, there are two main types of material-out-of-fill sensors: contact and non-contact. Contact sensors typically use detection electrodes that come into direct contact with the liquid, detecting the presence of liquid by measuring the electrical conductivity between the electrodes. However, when detecting corrosive liquids, the need for direct contact between the electrodes significantly reduces the sensor's service life.

[0005] Non-contact material shortage sensors, such as ultrasonic material shortage sensors, are installed outside the pump liquid pipe. Since they do not contact the liquid in the pump liquid pipe, their service life can be improved. However, they require complex ultrasonic generators, ultrasonic receivers and processing circuits inside, and the overall structure is complex and the cost is high. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a non-contact material shortage detection sensor, a dishwasher, and a method for detecting material shortage in a pump liquid pipe, which have a simple overall structure and low cost.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] In the first aspect, an embodiment of the present invention provides a material shortage detection sensor, comprising: a reference signal unit, a detection signal unit and a central processing unit; the reference signal unit is a first RC oscillation circuit; the detection signal unit is a second RC oscillation circuit, and the second RC oscillation circuit comprises: a detection resistor and the detection capacitor element, and the detection capacitor element comprises a detection electrode; the central processing unit comprises: a pulse generator and a signal comparator; wherein the reference signal unit and the detection signal unit are respectively connected to the pulse generator and the signal comparator; the pulse generator is used to send a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit, so that the reference signal unit and the detection signal unit are in a periodic charging or discharging state; the signal comparator is used to collect the voltage amplitude of the reference signal unit and the detection signal unit in the charging or discharging state, and output an indication signal for characterizing whether there is material shortage according to the time when the voltage amplitude rises or falls to the reference voltage value.

[0009] Preferably, the first RC oscillation circuit includes: a reference resistor and a reference capacitor, the reference resistor and the reference capacitor are connected in series, and one end of the reference resistor is connected to the pulse generator and the signal comparator; the detection resistor and the detection capacitor element are connected in series, and one end of the detection resistor is connected to the pulse generator and the signal comparator.

[0010] Preferably, the detection electrode is a clamping piece for clamping the material tube to be detected.

[0011] Preferably, the reference signal unit includes: one or at least two groups of reference signal sources, each group of the reference signal sources mainly consisting of a first RC oscillation circuit.

[0012] Preferably, the reference signal unit includes at least two groups of reference signal sources, each group of the reference signal sources is mainly composed of a first RC oscillation circuit, and a reference switch is provided on the line node between the at least two groups of reference signal sources and the pulse generator and the signal comparator.

[0013] Preferably, the signal comparator is specifically used to collect the voltage amplitudes of the reference signal part and the detection signal part in the charging or discharging state, and compare the time when the voltage amplitude of the reference signal part rises or falls to the reference voltage value with the time when the voltage amplitude of the detection signal part rises or falls to the reference voltage value. If they are consistent, an indication signal for indicating that there is material is output; if they are inconsistent, an indication signal for indicating that there is material shortage is output.

[0014] Preferably, the central processing unit further includes: a sensitivity adjustment unit, which is an oscillation circuit, and the output end of the sensitivity adjustment unit is electrically connected to the input end of the pulse generator and the control end of the signal comparator, and is used to adjust the frequency of the pulse signal emitted by the pulse generator and the reference voltage value of the signal comparator. The input end of the sensitivity adjustment unit is connected to a sensitivity adjustment capacitor, and the sensitivity adjustment capacitor is connected to a power supply.

[0015] Preferably, the central processing unit further includes: an output processing unit, the output processing unit is a filter circuit, the input end of the output processing unit is connected to the output end of the signal comparator, and the output end of the output processing unit is used to connect to the controller.

[0016] Preferably, the output end of the signal comparator is further provided with a detection status indicator; or the output end of the output processing unit is further provided with a detection status indicator.

[0017] Preferably, the material shortage detection sensor further comprises a housing, the reference signal unit and the central processing unit are arranged in the housing, a signal output line hole is reserved on the housing, and the detection capacitor element of the detection signal unit is located outside the housing; or,

[0018] The out-of-material detection sensor also includes a shell, and the sensor circuit package having the reference signal unit and the central processing unit is arranged in the shell, and a signal output line hole is reserved on the shell, and the detection capacitor element of the detection signal unit is located outside the shell.

[0019] In a second aspect, the present invention also provides an embodiment of a dishwasher, comprising: a casing, a cleaning water tank and a peristaltic pump provided in the casing, a pump liquid pipe of the peristaltic pump connected to the cleaning water tank for pumping cleaning liquid into the cleaning water tank, a material shortage detection sensor as described in any one of the first aspects being provided on the pump liquid pipe, and a detection capacitor element of the material shortage detection sensor being connected to the outside of the pump liquid pipe.

[0020] Compared with the non-contact ultrasonic material shortage detection sensor, the material shortage detection sensor provided by the embodiment of the present invention includes: a reference signal part, a detection signal part and a central processing unit. When used, the detection electrode of the detection signal part can be connected to the outside of the pump liquid pipe, and the monitoring of the liquid in the pump liquid pipe is realized based on the capacitance principle detection method; the overall structure is simple and the cost is low.

[0021] In a third aspect, the present invention further provides an embodiment of a method for detecting material shortage in a pump liquid pipe, which is implemented based on any material shortage detection sensor described in the first aspect, wherein a detection electrode of the material shortage detection sensor is deployed and installed outside the pump liquid pipe, and the detection capacitor element is mainly composed of the detection electrode, the pump liquid pipe, and the medium in the pump liquid pipe;

[0022] The method comprises the steps of: after the detergent is filled into the pump liquid pipe, collecting the voltage amplitudes of the reference signal portion and the detection signal portion in a charging or discharging state;

[0023] Outputting an indication signal indicating whether the pump liquid pipe is loaded with the wrong material based on the comparison of the time taken for the voltage amplitudes of the reference signal portion and the detection signal portion to rise or fall to the reference voltage value;

[0024] If the indication signal indicates that the material is not loaded incorrectly, the system enters the material shortage detection working state;

[0025] Sending a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit, so that the reference signal unit and the detection signal unit are in a periodic charging or discharging state;

[0026] collecting voltage amplitudes of the reference signal portion and the detection signal portion in a charging or discharging state;

[0027] The time taken for the voltage amplitudes of the reference signal portion and the detection signal portion to rise or fall to the reference voltage value is compared, and an indication signal for indicating whether there is a lack of material in the pump liquid pipe is output.

[0028] Optionally, this embodiment also provides a method for detecting material shortage in a pump liquid pipe, which is implemented based on a material shortage detection sensor of an embodiment of the first aspect, and the sending of a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit so that the reference signal unit and the detection signal unit are in a periodic charging or discharging state includes: receiving a first control signal sent by the control end; according to the first control signal, connecting the first group of reference signal sources of the reference signal unit with the pulse generator and the signal comparator through the reference switch; wherein the reference capacitance value of the first group of reference signal sources is calibrated based on the first washing liquid; sending a pulse signal of a predetermined frequency to the first group of reference signal sources and the detection signal unit so that the first group of reference signal sources and the detection signal unit are in a periodic charging or discharging state.

[0029] Optionally, the sending of a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit so that the reference signal unit and the detection signal unit are in a periodic charging or discharging state also includes: receiving a second control signal sent by the control end; according to the second control signal, connecting the second group of reference signal sources of the reference signal unit to the pulse generator and the signal comparator through the reference switch; wherein the reference capacitance value of the second group of reference signal sources is calibrated based on the second washing liquid; and sending a pulse signal of a predetermined frequency to the second group of reference signal sources and the detection signal unit so that the second group of reference signal sources and the detection signal unit are in a periodic charging or discharging state.

[0030] Optionally, the reference capacitance value of the first group of reference signal sources is the same as or different from the reference capacitance value of the second group of reference signal sources.

[0031] Optionally, the detection electrode of the material shortage detection sensor is deployed and installed outside the pump liquid pipe, including:

[0032] The detection electrodes of the material shortage detection sensor having a reference signal part and a set of reference signal sources are arranged and installed outside at least one detergent pump liquid pipe of the dishwasher; or

[0033] The detection electrodes of the material shortage detection sensor having a reference signal portion with multiple reference signal sources are arranged and installed on the outside of at least one detergent pump liquid pipe of the dishwasher;

[0034] The material shortage detection sensor is connected to a controller.

[0035] The material shortage detection method provided by the embodiment of the present invention is implemented based on the material shortage detection device provided by any embodiment of the first aspect. Based on the corresponding specific technical features, it can not only monitor the amount of material in the pump liquid pipe simply and conveniently; it can also automatically identify and detect whether the wrong washing liquid is loaded after loading the material into the pump liquid pipe, thereby preventing the technical problem of loading the wrong washing liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a schematic block diagram of a circuit of an embodiment of a material shortage detection sensor of the present invention;

[0038] Figure 2 This is a schematic block diagram of another embodiment of the circuit of the material shortage detection sensor of the present invention;

[0039] Figure 3 This is a structural diagram of an embodiment of a material shortage detection sensor of the present invention;

[0040] Figure 4 This is a front structural diagram of another embodiment of the material shortage detection sensor of the present invention;

[0041] Figure 5 for Figure 4 Schematic diagram of the back structure of the center-short material detection sensor;

[0042] Figure 6 The figure is a flow chart of a method for detecting material shortage according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0044] It should be understood that the embodiments described are only a portion 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 persons of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] Figure 1 This is a schematic block diagram of a circuit of an embodiment of a material shortage detection sensor of the present invention; Figure 2 This is a schematic block diagram of the circuit of another embodiment of the material shortage detection sensor of the present invention.

[0047] Please see Figure 1 and Figure 2 As shown, the material shortage detection sensor provided by the embodiment of the present invention is suitable for material detection scenarios, for example, detecting the amount of washing liquid required by dishwashers, washing machines, etc., and includes: a reference signal unit 62, a detection signal unit 63 and a central processor 61;

[0048] The reference signal unit 62 is a first RC (capacitor and resistor) oscillator circuit. This first RC oscillator circuit can be a series RC oscillator circuit, a parallel RC oscillator circuit, or a series-parallel RC oscillator circuit. Based on the technical concept of the present invention, those skilled in the art can freely select the specific circuit topology of the RC oscillator circuit.

[0049] In some embodiments, the reference signal unit includes: one or at least two groups of reference signal sources, each group of the reference signal sources is mainly composed of a first RC oscillation circuit.

[0050] like Figure 1 As shown, as an optional embodiment, the first RC oscillation circuit can be a simple RC oscillation circuit consisting of a resistor R10 and a capacitor C10 connected in series.

[0051] The detection signal unit 63 is a second RC oscillation circuit, which includes: a detection resistor R9 and the detection capacitor element, and the detection capacitor element includes a detection electrode; the central processing unit 61 includes: a pulse generator 612 and a signal comparator 613; wherein the reference signal unit 62 and the detection signal unit 63 are respectively connected to the pulse generator 612 and the signal comparator 613; the pulse generator 612 is used to send a pulse signal of a predetermined frequency to the reference signal unit 62 and the detection signal unit 63, so that the reference signal unit 62 and the detection signal unit 63 are in a periodic charging or discharging state.

[0052] The signal comparator 613 is used to collect the voltage amplitudes of the reference signal unit 62 and the detection signal unit 63 in the charging or discharging state, and output an indication signal for indicating whether there is a lack of material based on the time it takes for the voltage amplitude to rise or fall to the reference voltage value.

[0053] It is understandable that any substance can store a certain amount of charge, that is, it has capacitance characteristics. Because the dielectric constants of detergent liquid and air are different, the amount of charge that can be stored is also different, and the capacitance characteristics exhibited are different. Based on the different capacitance characteristics of liquid and air, the present invention creatively proposes a material shortage detection sensor. When in use, the detection electrode of the detection reference part is arranged on the outside of the pump liquid tube, which can realize the distinction between liquid and air in the pump liquid tube, thereby realizing non-contact detection of whether the washing liquid in the pump liquid tube is lacking.

[0054] It is understandable that different types of washing liquids have different corresponding capacitance characteristics. Therefore, before using the material shortage detection sensor to detect the washing liquid in the pump liquid tube, it is necessary to calibrate the reference signal unit 62. In some embodiments, the reference resistor R10 of the reference signal unit 62 and the detection resistor R9 of the detection signal unit 63 are both set to a reference resistance value, and the reference capacitor in the reference signal unit 62 is set to a reference capacitance value. This reference capacitance value is approximately equal to or equal to the sum of the capacitance values of the pump liquid tube filled with washing liquid and the detection electrode.

[0055] Compared with the non-contact ultrasonic material shortage detection sensor, the material shortage detection sensor provided by the embodiment of the present invention includes: a reference signal unit 62, a detection signal unit 63 and a central processing unit 61. When used, the detection electrode of the detection signal unit 63 can be connected to the outside of the pump liquid pipe, and the monitoring of the liquid in the pump liquid pipe is realized based on the capacitance principle detection method; the overall structure is simple and the cost is low.

[0056] Furthermore, the material shortage detection sensor based on the capacitance principle of the present invention requires few components, has a simple structure, low cost, a compact size, and is easy to install.

[0057] Furthermore, compared with the contact-type material shortage detection sensor, the detection electrode needs to be installed in the pump liquid pipe, the overall structure is complex, and because a gap needs to be set on the pipeline for installing the sensor, there is a risk of leakage.

[0058] The material shortage detection sensor provided by the present invention installs the detection electrode on the outside of the pump liquid tube when it is necessary to detect whether the washing liquid in the pump liquid tube is short of material. There is no need to open a gap in the pipeline, which is easy to install and can avoid the risk of leakage to a certain extent. Moreover, since it does not require direct contact with the liquid in the tube, the service life can be improved.

[0059] Please continue to see Figure 1 or Figure 2 As shown, the reference resistor R10 is connected in series with the reference capacitor C10, one end of the reference resistor R10 is connected to the pulse generator 612 and the signal comparator 613, and one end of the reference capacitor C10 is connected to the negative electrode of the power supply, and the negative electrode of the power supply can be grounded as a reference potential; when the sensor power supply is not powered on, the pulse generator 612 does not send a pulse signal to the reference resistor R10, and the reference capacitor has no charge. When the power is turned on, the pulse generator 612 sends a pulse signal of a specific frequency to the reference resistor R10 for charging or discharging; when the pulse signal is at a high level, the output current will pass through the reference resistor R10 to charge the reference capacitor C10, and when the pulse signal is at a low level, the charge in the reference capacitor C10 will be released through the reference resistor R10, so that the reference signal unit 62 is in a periodic charging or discharging state.

[0060] It is understood that the time it takes for the voltage to rise to the power supply voltage is related to the resistance of reference resistor R10 and the capacitance of reference capacitor C10. When reference resistor R10 remains unchanged, a larger capacitance of reference capacitor C10 results in a longer time for the voltage to rise to the power supply voltage; a smaller capacitance of reference capacitor C10 results in a shorter time for the voltage to rise to the power supply voltage.

[0061] The detection resistor R9 and the detection capacitor element are connected in series, and one end of the detection resistor R9 is connected to the pulse generator 612 and the signal comparator 613 .

[0062] Specifically, one end of the detection resistor R9 is indirectly connected to the positive electrode of the power supply of the material shortage detection sensor, and the other end of the detection resistor R9 is connected to the detection electrode. The detection electrode can be a metal component, and its shape can be designed according to the needs of the substance to be detected. The detection electrode and the negative electrode of the sensor power supply are separated by the substance to be detected. The detection electrode, air and the substance to be detected all have capacitance characteristics. The detection electrode and the substance to be detected as a whole can be regarded as forming a detection capacitor element, and its capacitance value is the detection capacitance value. When the sensor power supply is not energized, the detection capacitor is not charged. When the power is turned on, the current output by the power supply will charge the detection capacitor through the detection resistor R9. The voltage of the trigger detection point of the detection signal unit 63 will gradually rise to the power supply voltage. The time it takes for the voltage to rise to the power supply voltage is related to the resistance of the detection resistor R9 and the capacitance of the detection capacitor. When the detection resistor R9 is unchanged, the greater the capacitance of the detection capacitor element, the longer the time it takes for the voltage to rise to the power supply voltage. The smaller the capacitance of the detection capacitor element, the shorter the time it takes for the voltage to rise to the power supply voltage.

[0063] Since the capacitance value of the detection electrode 1 is related to the material and structure of the detection electrode itself, when the material and structure of the detection electrode 1 are fixed, the capacitance characteristics of the detection electrode 1 are also fixed. Therefore, when the capacitance characteristics of the substance to be detected change, the capacitance value of the detection capacitance element will also change; based on the capacitance value of the detection capacitance, the change in the amount of the substance to be detected can be determined, specifically the change in the amount of washing liquid in the pump liquid tube.

[0064] In order to facilitate the installation of the material shortage detection sensor outside the pump liquid pipe, Figures 3 to 5 As shown, in some embodiments, the detection electrode 1 is a clamping member used to clamp the material tube to be detected, and the clamping member can be made of conductive materials such as metal, conductive rubber, graphite, etc.

[0065] The detection electrode 1 can be a circular tube, nested in the liquid pipeline to be detected, or an arc-shaped electrode with an opening angle less than 180°, nested in the liquid pipeline to be detected, or a plate-shaped electrode, attached to the liquid pipeline to be detected. Figure 4 As shown, preferably, the detection electrode 1 adopts a tubular structure and is sleeved on the liquid pipeline to be detected.

[0066] The pulse generator 612 is capable of generating a square wave signal with a specific trigger frequency. The square wave signal is in a push-pull output state, i.e., the high state of the square wave corresponds to the positive state of the power supply, and the low state of the square wave corresponds to the negative state of the power supply. The square wave signal acts on the reference signal unit 62 and the detection signal unit 63, causing the reference capacitor of the reference signal unit 62 and the detection capacitor of the detection signal unit 63 to be periodically charged or discharged.

[0067] The signal comparator 613 is specifically used to collect the voltage amplitudes of the reference signal part 62 and the detection signal part 63 in the charging or discharging state, and compare the time when the voltage amplitude of the reference signal part 62 rises or falls to the reference voltage value with the time when the voltage amplitude of the detection signal part 63 rises or falls to the reference voltage value. If they are consistent, an indication signal for indicating that there is material is output; if they are inconsistent, an indication signal for indicating that there is material shortage is output.

[0068] The signal comparator 613 detects the voltage amplitudes at the trigger detection points of the reference signal unit 62 and the detection signal unit 63 in real time. Under the influence of the square wave signal of the pulse generator 612, the reference signal unit 62 and the detection signal unit 63 are in the process of charging or discharging. The voltage amplitudes of the reference signal unit 62 and the detection signal unit 63 are in the process of rising or falling. The signal comparator 613 is provided with a reference voltage value. The signal comparator 613 compares the time it takes for the voltage amplitudes of the reference signal unit 62 and the detection signal unit 63 to rise or fall to the reference voltage in real time.

[0069] If the time it takes for the voltage amplitudes of the reference signal unit 62 and the detection signal unit 63 to rise or fall to the reference voltage value is equal, it indicates that the detection capacitance is equal to the reference capacitance, and a material presence signal is output. If the time it takes for the voltage amplitudes of the reference signal unit 62 and the detection signal unit 63 to rise or fall to the reference voltage value is unequal, it indicates that the detection capacitance is not equal to the reference capacitance, and a material shortage signal is output.

[0070] Specifically, the material presence signal may be represented by a low-level signal, and the material shortage signal may be represented by a high-level signal.

[0071] In order to facilitate the adjustment of the detection sensitivity of the material shortage detection sensor, in some embodiments, the central processor 61 further includes: a sensitivity adjustment unit 611, the sensitivity adjustment unit 611 is an oscillation circuit, the output end of the sensitivity adjustment unit 611 is electrically connected to the input end of the pulse generator 612 and the control end of the signal comparator 613, and is used to adjust the frequency of the pulse signal emitted by the pulse generator 612 and the reference voltage value of the signal comparator 613. The input end of the sensitivity adjustment unit 611 is connected to a sensitivity adjustment capacitor C9, and the sensitivity adjustment capacitor C9 is connected to the negative pole of the power supply, and the negative pole of the power supply is grounded.

[0072] The sensitivity adjustment unit 611 controls the specific frequency of the square wave pulse signal emitted by the pulse generator 612 and the reference voltage of the signal comparator 613. It is understood that the trigger frequency of the pulse generator 612 and the reference voltage of the signal comparator 613 are related to the supply voltage. The sensitivity adjustment unit 611 is connected to the sensitivity adjustment capacitor C9, which controls both the specific trigger frequency of the pulse generator 612 and the reference voltage of the signal comparator 613. The relationship between the specific trigger frequency and the reference voltage is controlled by the sensitivity adjustment unit 611. By adjusting the capacitance of the sensitivity adjustment capacitor C9, the specific trigger frequency of the pulse generator 612 and the reference voltage of the signal comparator 613 can be simultaneously changed, thereby adjusting the detection sensitivity of the material shortage detection sensor.

[0073] In this embodiment, the capacitance value of the capacitor corresponding to different washing liquids is determined as follows: first, the detection electrode 1 is set outside the liquid pipeline to be detected, forming a detection capacitor element with the empty liquid pipeline to be detected, and the capacitance of the reference signal part 62 is adjusted so that the detection status indicator part displays the no-material detection state.

[0074] Then, the liquid to be detected is introduced into the liquid pipeline to be detected. At this time, the detection capacitor element is composed of the detection electrode 1 and the liquid pipeline to be detected with the detection liquid. By adjusting the reference capacitance of the reference signal part 62, the detection status indicator part displays the material detection state.

[0075] Please continue to see Figure 1 and Figure 2 As shown, in some embodiments, the central processing unit 61 further includes: an output processing unit 614, the output processing unit 614 is a filtering circuit, the input end of the output processing unit 614 is connected to the output end of the signal comparator 613, the output end of the output processing unit 614 is used to connect to a controller (not shown in the figure), and the output end of the output processing unit 614 is specifically connected to the connector H1, and is connected to the upper-level controller through the connector H1.

[0076] The signal comparison unit transmits the detected signal indicating material shortage to the output processing unit 614. The output processing unit 614 filters the signal indicating material shortage to eliminate interference caused by unstable capacitance characteristics of the test material, pulse generator 612, or signal comparator 613. The output processing unit 614 outputs the filtered electrical signal; even after filtering, the signal indicating material shortage still outputs the same electrical signal.

[0077] Please continue to see Figure 1Or as shown in Figure 2, in order to intuitively indicate whether the washing liquid in the pump liquid tube is lacking, in some embodiments, the output end of the signal comparator 613 is also provided with a detection status indicator 5; or, the output end of the output processing unit 614 is also provided with a detection status indicator 5.

[0078] When the signal comparator 613 or the output processing unit 614 outputs a material presence electrical signal, the detection status indicator will display the material presence detection state. When the output processing unit 614 outputs a material absence electrical signal, the detection status indicator will display the material absence detection state. This facilitates intuitively indicating whether the cleaning liquid in the pump liquid pipe is lacking, which is beneficial for factory testing of the sensor and intuitive display of the liquid state during actual use.

[0079] Specifically, the detection status indicator 5 is a light or sound indicator. For example, the detection status indicator 5 uses an LED light. When the signal comparator 613 or the output processing unit 614 outputs a material-containing electrical signal, the light indicator lights up, and when there is no material, the light indicator turns off.

[0080] Please see Figure 3 As shown, the reference signal unit 62 and the central processing unit 61 are packaged into a module to constitute a sensor circuit package 6. The detection status indicator 5 is provided on the first surface of the sensor circuit package 6. The detection status indicator 5 is electrically connected to the sensor circuit package 6. The specific circuit topology can be found in the above-mentioned related description and will not be repeated here.

[0081] The detection electrode 1 is provided on the second surface of the sensor circuit package 6. In some embodiments, a detection electrode fixing seat 2 is provided on the second surface of the sensor circuit package 6, and the detection electrode 1 is mounted on the detection electrode fixing seat 2.

[0082] Please continue to see Figure 1 Detection electrode 1 is directly attached to detection electrode holder 2, which is directly connected to the printed circuit board (PCB) within sensor circuit package 6. Reference signal unit 62, central processing unit 61, detection status indicator unit, and detection resistor R9 of detection signal unit 63 are all soldered to the sensor PCB. The material shortage detection sensor provided in this embodiment has a simple overall detection principle and structure, resulting in low cost.

[0083] Please continue to see Figure 3 and Figure 4As shown, the material shortage detection sensor further includes a housing 3, the reference signal unit 62 and the central processing unit 61 are arranged in the housing 3, and a signal output line hole is reserved on the housing 3 for passing the signal cable 4, and the detection capacitor element of the detection signal unit 63, that is, the detection electrode 1 is located outside the housing 3; or,

[0084] The material shortage detection sensor further includes a housing 3. A sensor circuit package 6 having the reference signal unit 62 and a central processing unit 61 is disposed within the housing 3. A signal output hole is reserved on the housing 3 for passing a signal cable 4 therethrough. The detection capacitor element of the detection signal unit 63 is located outside the housing 3. The outside herein includes the outer surface and the space outside the outer surface.

[0085] The reference signal unit 62, the central processing unit 61, the detection state indicating unit and the detection resistor R9 of the detection signal unit 63, and the sensor PCB are encapsulated in the shell by plastic packaging, which plays a role in dustproof and waterproof, and prolongs the service life of the short-material detection sensor.

[0086] As can be seen from the foregoing description, the low-material detection sensor provided by the embodiments of the present invention enables non-contact detection of material in the pump liquid pipe. It features a simple circuit topology and overall structure, low cost, compact size, and easy installation. Furthermore, it can be adapted to cleaning scenarios where multiple cleaning solutions are used alternately or simultaneously, and is easy to maintain.

[0087] The capacitance value of the detection capacitor element is determined based on the reference capacitance in the no-fill and fill detection states. If the liquid to be detected is not unique, calibration is performed for different liquids to be detected, and a reference capacitance that can detect all liquids to be detected is selected. The sensitivity adjustment capacitor C9 can be adjusted accordingly according to the display state of the status indicator to determine the capacitance value that is sensitive only to the liquid to be detected.

[0088] Example 2

[0089] In a dishwasher, multiple detergents are sometimes needed to complete different cleaning steps. Detergents with different functions have different liquid components, resulting in different ion concentrations in the detergents. Therefore, the dielectric constants of different detergents are also different, and the capacitance characteristics they exhibit are also different.

[0090] Therefore, in order to adapt to the detection of detergents with different components in the pump liquid tube, such as Figure 2 As shown, in some embodiments, the reference signal unit 62 includes at least two groups of reference signal sources, each of which is mainly composed of a first RC oscillator circuit, and a reference switch 621 (i.e., Figure 2It should be noted that, in order to distinguish different embodiments, Figure 1 The reference signal section 62 in Figure 2 In the figure, it is shown as the reference signal portion 62'.

[0091] The reference signal values of the two groups of reference signal sources may be the same or different. Specifically, Figure 1 The reference signal section 62 in the embodiment shown is adjusted to Figure 2 The variable reference signal section 62' shown in FIG. The variable reference signal section 62' is composed of a reference switch 621 and a plurality of RC oscillation circuits.

[0092] Please continue to see Figure 2 As shown, in some implementation cases, there are 4 groups of RC oscillation circuits in the variable reference signal unit 62', that is, 4 groups of reference signal sources. Each group of reference signal units 62 is composed of a reference resistor and a reference capacitor. The resistance values of the reference resistors in the 4 groups of reference signal sources are R1, R2, R3 and R4 respectively, and the capacitance values of the reference capacitors in the 4 groups of reference signal sources are C1, C2, C3 and C4 respectively. The principle of each group of reference signal sources is consistent with that of the aforementioned reference signal unit 62, and will not be repeated here. Please refer to the aforementioned related description.

[0093] The four reference signal sources are connected to a reference switch 621. Reference switch 621 is connected to the pulse generator 612 and the signal comparator 613. The control terminal of reference switch 621 can be connected to the H1 connector and then to the controller via an external cable. Of course, reference selector 621 itself can also be manually selected. Reference switch 621 can be considered a programmable analog switch, capable of selecting different reference signal sources for connection to the pulse generator 612 and the signal comparator 613 via control signals from the control terminal, thereby switching between different reference signal sources.

[0094] In this embodiment, by providing a reference switch 621 and multiple groups of reference signal sources, different reference signal sources can be selected to be connected to the pulse generator 612 and the signal comparator 613, thereby adapting to the detection of different detergents.

[0095] For example, when deploying the out-of-stock detection sensor of this embodiment, assuming a dishwasher uses four different detergent compositions, the detergent solutions are first prepared and the electronic components of the four oscillation sensors in the reference signal unit 62 are calibrated. After calibration, the reference capacitance values C1, C2, C3, and C4 for detergent type 1, are obtained for detergent type 1, detergent type 2, detergent type 3, and detergent type 4, respectively. Once the reference capacitance values are determined, an out-of-stock detection sensor is manufactured with these reference capacitance values.

[0096] There are mainly the following solutions for deploying the short-term detection sensor on the equipment: First, the dishwasher has a detergent pump pipe, and the sensor is deployed and installed outside the pump pipe. Figure 1 The material shortage detection sensor shown or Figure 2 The material shortage detection sensor shown has multiple sets of switchable reference signal sources.

[0097] The second type is that the dishwasher has multiple detergent pump liquid pipes, each of which can correspond to one of the above-mentioned out-of-material detection sensors. All of the out-of-material detection sensors are connected to the upper-layer controller. The controller can control the capacitance of the reference capacitor selected by each out-of-material detection sensor through the reference switch 621 through a program, and can set each out-of-material detection sensor to detect the detergent with the corresponding composition.

[0098] The third type is a dishwasher with multiple detergent pump pipes, at least one of which is deployed Figure 1 The material shortage detection sensor shown is deployed in at least one Figure 2 The material shortage detection sensor shown has multiple sets of switchable reference signal sources.

[0099] Based on the above design, when multiple detergents are deployed in a dishwasher, each low-dose sensor can detect a shortage based on the status of its selected reference signal. Furthermore, when a detergent runs out and needs to be replaced, the corresponding low-dose sensor can distinguish whether the calibrated detergent has been deployed and alert the deployment personnel through a status indicator, allowing timely detection of detergent deployment errors.

[0100] Example 3

[0101] Based on the same technical concept as Example 1, the present invention also provides an embodiment of a dishwasher, including: a casing, a cleaning water tank and a peristaltic pump are provided in the casing, a pump liquid pipe of the peristaltic pump is connected to the cleaning water tank, and is used to pump cleaning liquid into the cleaning water tank, a material shortage detection sensor described in any one of Example 1 is provided on the pump liquid pipe, and a detection capacitor element of the material shortage detection sensor is connected to the outside of the pump liquid pipe.

[0102] It is understandable that in order to highlight the innovative spirit of the present invention, the basic components of the dishwasher and components that are not closely related to the improvements of this application will not be described in detail. Those skilled in the art can choose or design them on their own based on the technical inspiration of the present invention.

[0103] In one embodiment of the present invention, a controller is further provided in the housing, and the controller is electrically connected to the peristaltic pump and the material shortage detection sensor respectively; and / or,

[0104] The pump liquid pipe is provided with multiple paths, and the outside of each pump liquid pipe is provided with the material shortage detection sensor.

[0105] The dishwasher provided in the embodiment of the present invention detects the washing liquid in the pump liquid pipe based on the lack of material detection sensor of the above embodiment. The washing liquid detection method is simple and easy to maintain.

[0106] Example 4

[0107] Based on any of the material shortage detection sensors provided in Example 1, please refer to Figure 6 As shown, the present invention also provides a method for detecting material shortage in a pump liquid tube in an embodiment, wherein the detection electrode of the material shortage detection sensor is deployed and installed on the outside of the pump liquid tube, and the detection capacitor element is mainly composed of the detection electrode, the pump liquid tube and the medium in the pump liquid tube; wherein the medium can be air or liquid, and can also be a coexistence state of air and liquid; that is, when the material liquid in the pump liquid tube is completely emptied, the detection capacitor element is mainly composed of the detection electrode, the pump liquid tube and the air therein; when the material liquid in the pump liquid tube is full, the detection capacitor element is mainly composed of the detection electrode, the pump liquid tube and the material liquid therein; when the material liquid in the pump liquid tube is lacking, the detection capacitor element is mainly composed of the detection electrode, the pump liquid tube and the material liquid therein and air.

[0108] The method comprises the steps of:

[0109] After the detergent is filled into the pump liquid pipe, step S410 is executed to collect the voltage amplitudes of the reference signal unit and the detection signal unit in the charging or discharging state;

[0110] S420, outputting an indication signal indicating whether the pump liquid pipe is loaded with the wrong material based on the comparison of the time taken for the voltage amplitudes of the reference signal unit and the detection signal unit to rise or fall to the reference voltage value;

[0111] S430: If the indication signal indicates that the material is not loaded incorrectly, the system enters the material shortage detection working state;

[0112] In this embodiment, by performing the above steps after filling the filling liquid into the pump liquid tube, it can be automatically identified and detected whether the wrong washing liquid is loaded, thereby preventing the technical problem of loading the wrong washing liquid.

[0113] If the wrong material is installed, repeat the steps of changing the cleaning liquid and the above steps until the correct cleaning liquid is installed, and then perform the following steps.

[0114] S440, sending a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit, so that the reference signal unit and the detection signal unit are in a periodic charging or discharging state;

[0115] S450, collecting voltage amplitudes of the reference signal unit and the detection signal unit in a charging or discharging state;

[0116] S460: Compare the time taken for the voltage amplitudes of the reference signal unit and the detection signal unit to rise or fall to the reference voltage value, and output an indication signal for indicating whether there is a lack of material in the pump liquid pipe.

[0117] The material shortage detection method provided by the embodiment of the present invention is implemented based on the material shortage detection device provided by any embodiment of the first aspect. Based on the corresponding specific technical features, it can not only monitor the amount of material in the pump liquid pipe simply and conveniently; it can also automatically identify and detect whether the wrong washing liquid is loaded after loading the material into the pump liquid pipe, thereby preventing the technical problem of loading the wrong washing liquid.

[0118] Based on the material shortage detection sensor provided in one embodiment of the second embodiment, in the material shortage detection method provided in the embodiment of the present invention, the step of sending a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit to put the reference signal unit and the detection signal unit into a periodic charging or discharging state includes: receiving a first control signal sent by a control terminal;

[0119] According to the first control signal, the first set of reference signal sources of the reference signal unit is connected to the pulse generator and the signal comparator through the reference switch; wherein the reference capacitance value of the first set of reference signal sources is calibrated based on the first washing liquid;

[0120] A pulse signal of a predetermined frequency is sent to the first group of reference signal sources and the detection signal unit, so that the first group of reference signal sources and the detection signal unit are in a periodic charging or discharging state.

[0121] Furthermore, the sending of a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit so that the reference signal unit and the detection signal unit are in a periodic charging or discharging state also includes: receiving a second control signal sent by the control end; according to the second control signal, connecting the second group of reference signal sources of the reference signal unit with the pulse generator and the signal comparator through the reference switch; wherein the reference capacitance value of the second group of reference signal sources is calibrated based on the second washing liquid; and sending a pulse signal of a predetermined frequency to the second group of reference signal sources and the detection signal unit so that the second group of reference signal sources and the detection signal unit are in a periodic charging or discharging state.

[0122] The reference capacitance value of the first group of reference signal sources is the same as or different from the reference capacitance value of the second group of reference signal sources.

[0123] In some embodiments, the detection electrode of the material shortage detection sensor is deployed and installed outside the pump liquid pipe, including:

[0124] The detection electrodes of the material shortage detection sensor having a reference signal part and a set of reference signal sources are arranged and installed outside at least one detergent pump liquid pipe of the dishwasher; or

[0125] The detection electrodes of the material shortage detection sensor having a reference signal portion with multiple reference signal sources are arranged and installed on the outside of at least one detergent pump liquid pipe of the dishwasher;

[0126] The material shortage detection sensor is connected to a controller.

[0127] According to the above description, the material shortage detection method provided in this embodiment can not only monitor the amount of material in the pump liquid pipe simply and conveniently; it can also automatically identify and detect whether the wrong washing liquid is loaded after loading the pump liquid pipe (including initial loading and replacement of the material liquid), thereby preventing technical problems caused by personnel loading the wrong washing liquid.

[0128] It should be noted that, in this document, terms such as "upper" and "lower" that indicate orientation or positional relationships are used solely to facilitate description and simplify the present invention. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly, meaning, for example, fixedly connected, removably connected, or integrally connected; directly connected or indirectly connected through an intermediary. Relational terms such as "first and second" are used solely to distinguish one entity or operation from another and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further restrictions, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element. For those skilled in the art, this can be understood based on the specific circumstances.

[0129] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A material shortage detection sensor, characterized in that: Deployed and installed outside the pump liquid pipe, including: reference signal part, detection signal part and central processing unit; The reference signal unit is a first RC oscillator circuit; The detection signal unit is a second RC oscillation circuit, and the second RC oscillation circuit includes: a detection resistor and a detection capacitor element, and the detection capacitor element includes a detection electrode; The central processing unit includes: a pulse generator and a signal comparator; Wherein, the reference signal unit and the detection signal unit are connected to the pulse generator and the signal comparator respectively; The pulse generator is used to send a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit, so that the reference signal unit and the detection signal unit are in a periodic charging or discharging state; The signal comparator is used to collect the voltage amplitudes of the reference signal portion and the detection signal portion in the charging or discharging state, compare the voltage amplitudes of the reference signal portion and the detection signal portion based on the time it takes for the voltage amplitudes to rise or fall to the reference voltage value, and output an indication signal indicating whether the pump liquid pipe is loaded with the wrong material; if the indication signal indicates that the wrong material is loaded, output an indication signal indicating whether the material is out of stock based on the time it takes for the voltage amplitude to rise or fall to the reference voltage value; The reference signal unit includes at least two groups of reference signal sources, each group of the reference signal sources includes a first RC oscillator circuit, and a reference switch is provided at the line node between the at least two groups of reference signal sources and the pulse generator and the signal comparator; The first RC oscillator circuit includes: a reference resistor and a reference capacitor, the reference resistor and the reference capacitor are connected in series, and one end of the reference resistor is connected to the pulse generator and the signal comparator; The detection resistor and the detection capacitor element are connected in series, and one end of the detection resistor is connected to the pulse generator and the signal comparator.

2. The material shortage detection sensor according to claim 1, characterized in that: The detection electrode is a clamping piece used to clamp the material pipe to be detected.

3. The material shortage detection sensor according to claim 1, characterized in that: The reference signal unit includes: one or at least two groups of reference signal sources, each group of the reference signal sources is mainly composed of a first RC oscillation circuit.

4. The material shortage detection sensor according to claim 1, characterized in that: The signal comparator is specifically used to collect the voltage amplitudes of the reference signal part and the detection signal part in the charging or discharging state, and compare the time when the voltage amplitude of the reference signal part rises or falls to the reference voltage value with the time when the voltage amplitude of the detection signal part rises or falls to the reference voltage value. If they are consistent, an indication signal for indicating that there is material is output; If they are inconsistent, an indication signal indicating material shortage is output.

5. The material shortage detection sensor according to claim 1, characterized in that: The central processing unit also includes: a sensitivity adjustment unit, which is an oscillation circuit. The output end of the sensitivity adjustment unit is electrically connected to the input end of the pulse generator and the control end of the signal comparator, and is used to adjust the frequency of the pulse signal emitted by the pulse generator and the reference voltage value of the signal comparator. The input end of the sensitivity adjustment unit is connected to a sensitivity adjustment capacitor, and the sensitivity adjustment capacitor is connected to a power supply.

6. The material shortage detection sensor according to claim 1, characterized in that: The central processing unit further includes an output processing unit, which is a filter circuit. The input end of the output processing unit is connected to the output end of the signal comparator, and the output end of the output processing unit is used to connect to a controller.

7. The material shortage detection sensor according to claim 6, characterized in that: The output end of the signal comparator is also provided with a detection status indicator; or, The output end of the output processing unit is also provided with a detection status indicator.

8. The material shortage detection sensor according to claim 1, characterized in that: The material shortage detection sensor further includes a housing, the reference signal unit and the central processing unit are arranged in the housing, a signal output line hole is reserved on the housing, and the detection capacitor element of the detection signal unit is located outside the housing; or, The out-of-material detection sensor also includes a shell, and the sensor circuit package having the reference signal unit and the central processing unit is arranged in the shell, and a signal output line hole is reserved on the shell, and the detection capacitor element of the detection signal unit is located outside the shell.

9. A dishwasher, characterized in that: include: A housing is provided with a cleaning water tank and a peristaltic pump inside the housing, a pump liquid pipe of the peristaltic pump is connected to the cleaning water tank for pumping cleaning liquid into the cleaning water tank, a material shortage detection sensor according to any one of claims 1 to 8 is provided on the pump liquid pipe, and a detection capacitor element of the material shortage detection sensor is connected to the outside of the pump liquid pipe.

10. The dishwasher according to claim 9, characterized in that A controller is further provided in the housing, and the controller is electrically connected to the peristaltic pump and the material shortage detection sensor respectively; and / or, The pump liquid pipe is provided with multiple paths, and the outside of each pump liquid pipe is provided with the material shortage detection sensor.

11. A method for detecting material shortage in a pump liquid pipe, characterized in that: Based on the implementation of the material shortage detection sensor according to any one of claims 1 to 8, the detection electrode of the material shortage detection sensor is deployed and installed outside the pump liquid pipe, and the detection capacitor element is mainly composed of the detection electrode, the pump liquid pipe and the medium in the pump liquid pipe; The method comprises the steps of: after the detergent is filled into the pump liquid pipe, collecting the voltage amplitudes of the reference signal portion and the detection signal portion in a charging or discharging state; Outputting an indication signal indicating whether the pump liquid pipe is loaded with the wrong material based on the comparison of the time taken for the voltage amplitudes of the reference signal portion and the detection signal portion to rise or fall to the reference voltage value; If the indication signal indicates that the material is not loaded incorrectly, the system enters the material shortage detection working state; Sending a pulse signal of a predetermined frequency to the reference signal unit and the detection signal unit, so that the reference signal unit and the detection signal unit are in a periodic charging or discharging state; collecting voltage amplitudes of the reference signal portion and the detection signal portion in a charging or discharging state; The time taken for the voltage amplitudes of the reference signal portion and the detection signal portion to rise or fall to the reference voltage value is compared, and an indication signal for indicating whether there is a lack of material in the pump liquid pipe is output.

Images