Pole piece polarity reversal circuit and application

Abstract

The invention discloses a pole piece polarity reversal circuit and application, and belongs to the field of liquid level detection and electrolysis of liquid or foam, and the pole piece polarity reversal circuit comprises a control signal circuit, a polarity reversal circuit, a detection signal output circuit, an electrode, a signal processing circuit and a power supply; the control signal circuit is electrically connected with the polarity reversal circuit; the polarity reversal circuit is electrically connected with the detection signal output circuit, and the detection signal output circuit is used for detecting signal output; the polarity reversal circuit is connected with the electrode and is used for detecting the liquid level of the liquid or the foam; the electrode is connected with a signal processing circuit, and the signal processing circuit comprises a first-stage signal processing circuit or a multi-stage signal processing circuit; the signal processing circuit is used for reducing current flowing between the two pole pieces; the problem that the polarity of the liquid level detection pole piece is unchanged in a single direction for a long time is solved through the pole piece polarity reversal circuit, polarity reversal can be controlled at any time or in a preset time, damage to the pole piece is avoided, and the service life of the pole piece is prolonged.

Description

Technical Field

[0001] The invention relates to the field of liquid level detection and electrolysis of liquid or foam, and in particular to a pole piece polarity reversal circuit and application thereof. Background Art

[0002] Liquid level detection can help industrial enterprises to grasp the inventory of materials or chemicals in a timely manner, so as to arrange production plans in a timely and accurate manner and improve production efficiency. By monitoring the liquid level in real time, the staff can detect abnormal conditions in time and take immediate measures to repair them. Liquid level detection can realize remote monitoring without manual measurement, greatly reducing the danger of staff and ensuring the safety of staff. In industrial production scenarios, liquid level detection can realize automatic control to avoid excessive start or stop of equipment, protect production equipment and products, and reduce the occurrence of damage during production. Liquid level detection technology can be widely used in the field of industrial production, such as the petroleum and petrochemical industry, the pharmaceutical industry, and the food processing industry. Its benefits are to improve production efficiency, ensure the safety of staff, and avoid damage to equipment or products. At the same time, liquid level detection also brings many considerable economic benefits to enterprises. The electrode plays a good role in the liquid level detection of liquid or foam, and the electrode is also an important component in electrolysis.

[0003] However, in existing liquid or foam level detection devices or electrolysis, long-term unidirectional power supply between two electrodes will cause great damage to the electrodes and reduce the service life of the electrodes. There is an urgent need for a circuit to solve this problem. Summary of the invention

[0004] With regard to the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide a pole piece polarity reversal circuit and application to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A pole piece polarity reversal circuit, comprising a control signal circuit, a polarity reversal circuit, a detection signal output circuit, an electrode, a signal processing circuit and a power supply; the control signal circuit outputs two groups of control signals, the control signal circuit is electrically connected to the polarity reversal circuit, and the polarity reversal circuit comprises an isolated polarity reversal circuit or a non-isolated polarity reversal circuit; the polarity reversal circuit is electrically connected to the detection signal output circuit, and the detection signal output circuit is used to output the detection signal; the polarity reversal circuit is connected to the electrode, and the electrode comprises two groups of pole pieces or more than two groups of pole pieces, and is used to detect the liquid level of the liquid or foam; the electrode is connected to the signal processing circuit, and one pole piece is matched with one signal processing circuit, and the signal processing circuit comprises a primary signal processing circuit or a multi-stage signal processing circuit; the signal processing circuit is used to reduce the current flowing between the two pole pieces;

[0007] The power supply is electrically connected to the control signal circuit, the polarity reversal circuit, and the detection signal output circuit.

[0008] As a further solution of the present invention: the polarity reversal circuit is an isolated polarity reversal circuit, and the isolated polarity reversal circuit includes an optical coupler PH1, an optical coupler PH2, an optical coupler PH3, a resistor 11, a resistor 12, a resistor 13, a diode D1 and a diode D2;

[0009] The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2;

[0010] The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2, and the anode of the optocoupler PH2 is connected to the power supply V2;

[0011] The power source V1 is connected to one end of the resistor R12, and the other end of the resistor R12 is simultaneously connected to the collector of the optocoupler PH1 and the collector of the optocoupler PH2;

[0012] The power supply V1 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to the anode of the optocoupler PH3, and the cathode of the optocoupler PH3 is connected to the collector of the optocoupler PH1 and the collector of the optocoupler PH2 at the same time; the emitter of the optocoupler PH3 is connected to the ground G2, and the collector of the optocoupler PH3 is connected to the detection signal output circuit for outputting the detection signal; the power supply V2 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the collector of the optocoupler PH3.

[0013] As a further solution of the present invention: the polarity reversal circuit is an isolated polarity reversal circuit, and the isolated polarity reversal circuit includes an optical coupler PH1, an optical coupler PH2, an optical coupler PH3, a transistor Q2, a resistor 11, a resistor 12, a resistor 13, a diode D1 and a diode D2;

[0014] The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2;

[0015] The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2, and the anode of the optocoupler PH2 is connected to the power supply V2;

[0016] The power source V1 is connected to one end of the resistor R12, and the other end of the resistor R12 is simultaneously connected to the base of the transistor Q2, the collector of the optocoupler PH1, and the collector of the optocoupler PH2;

[0017] The power supply V1 is connected to the emitter of the transistor Q2, the collector of the transistor Q2 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to the anode of the optocoupler PH3, and the cathode of the optocoupler PH3 is connected to the ground G1; the emitter of the optocoupler PH3 is connected to the ground G2, and the collector of the optocoupler PH3 is connected to the detection signal output circuit for outputting the detection signal; the power supply V2 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the collector of the optocoupler PH3.

[0018] As a further solution of the present invention: the electrode includes two groups of pole pieces, the electrode includes pole piece one and pole piece two; the emitter of the optocoupler PH1 is connected to the positive pole of the diode D1, the negative pole of the diode D1 is connected to the pole piece one, the emitter of the optocoupler PH2 is connected to the positive pole of the diode D2, and the negative pole of the diode D2 is connected to the pole piece two.

[0019] As a further solution of the present invention: the polarity reversal circuit is a non-isolated polarity reversal circuit, the non-isolated polarity reversal circuit includes transistor Q5, transistor Q6, transistor Q7, resistor 11, diode D1 and diode D2; the electrode includes two sets of pole pieces, the electrode includes pole piece 1 and pole piece 2;

[0020] The control signal 1 output by the control signal circuit is connected to the base of the transistor Q6, the emitter of the transistor Q6 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the pole piece 1;

[0021] The control signal 2 output by the control signal circuit is connected to the base of the transistor Q5, the emitter of the transistor Q5 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the pole piece 2;

[0022] The power source V1 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to the collector of the transistor Q5 and the collector of the transistor Q6 at the same time;

[0023] The power source V1 is connected to the emitter of the transistor Q7, and the collector of the transistor Q7 is connected to the detection signal output circuit for outputting the detection signal;

[0024] The electrodes are connected to a signal processing circuit.

[0025] As a further solution of the present invention: the signal processing circuit is a primary signal processing circuit, and the primary signal processing circuit includes a transistor Q1, a transistor Q3, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a resistor R7 and a resistor R8;

[0026] The collector of the transistor Q1 in the primary signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the cathode of the diode D1, the emitter of the transistor Q1 is connected to the ground G1, the base of the transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3 at the same time, the other end of the resistor R2 is connected to the anode of the diode D2, and the other end of the resistor R3 is connected to the ground G1;

[0027] The collector of the transistor Q3 in the primary signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the cathode of the diode D2, the emitter of the transistor Q3 is connected to the ground G1, the base of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 at the same time, the other end of the resistor R7 is connected to the anode of the diode D1, and the other end of the resistor R8 is connected to the ground G1.

[0028] As a further solution of the present invention: the signal processing circuit is a multi-stage signal processing circuit, and the multi-stage signal processing circuit includes transistor Q1, transistor Q2, transistor Q3, transistor Q4, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, capacitor C1, capacitor C2, capacitor C3 and capacitor C4;

[0029] The collector of the transistor Q1 in the multi-stage signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the negative electrode of the diode D1, the emitter of the transistor Q1 is simultaneously connected to the base of the transistor Q2, one end of the resistor R3, one end of the resistor R4, and one end of the capacitor C1, the other end of the resistor R4 and the other end of the capacitor C1 are both connected to the ground G1, the other end of the resistor R3 and one end of the resistor R2 are both connected to the base of the transistor Q1, the other end of the resistor R2 is connected to the positive electrode of the diode D2, the emitter of the transistor Q2 is connected to the ground G1, the collector of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the positive electrode of the diode D2, and the capacitor C2 is connected in parallel between the collector of the transistor Q2 and the emitter of the transistor Q2;

[0030] The collector of the transistor Q3 in the multi-stage signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the cathode of the diode D2, the emitter of the transistor Q3 is simultaneously connected to the base of the transistor Q4, one end of the resistor R8, one end of the resistor R9, and one end of the capacitor C3, the other end of the resistor R9 and the other end of the capacitor C3 are both connected to the ground G1, the other end of the resistor R8 and one end of the resistor R7 are both connected to the base of the transistor Q3, the other end of the resistor R7 is connected to the anode of the diode D1, the emitter of the transistor Q4 is connected to the ground G1, the collector of the transistor Q4 is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the anode of the diode D1, and the capacitor C4 is connected in parallel between the collector of the transistor Q4 and the emitter of the transistor Q4.

[0031] As a further solution of the present invention: the polarity reversal circuit is an isolated polarity reversal circuit, the isolated polarity reversal circuit includes an optical coupler PH1, an optical coupler PH2, an optical coupler PH3, an optical coupler PH4, a resistor 14, a resistor 15, a resistor 16, a diode group D1, a diode group D2 and a diode group D3; the electrode includes more than two groups of pole pieces, and the electrode includes pole piece 1, pole piece 2 and pole piece 3;

[0032] The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2;

[0033] The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2 and the cathode of the optocoupler PH3, and the anode of the optocoupler PH2 and the anode of the optocoupler PH3 are connected to the power supply V2;

[0034] The power source V1 is connected to one end of the resistor R15, and the other end of the resistor R15 is connected to the collector of the optical coupler PH1 and the collector of the optical coupler PH2 at the same time;

[0035] The power supply V1 is connected to one end of the resistor R14, the other end of the resistor R14 is connected to the anode of the optocoupler PH4, and the cathode of the optocoupler PH4 is connected to the collector of the optocoupler PH1 and the collector of the optocoupler PH2 at the same time; the emitter of the optocoupler PH4 is connected to the ground G2, and the collector of the optocoupler PH4 is connected to the detection signal output circuit for outputting the detection signal; the power supply V2 is connected to one end of the resistor R16, and the other end of the resistor R16 is connected to the collector of the optocoupler PH4.

[0036] As a further solution of the present invention: the electrode includes pole piece 1, pole piece 2, and pole piece 3, the emitter of the optical coupler PH1 is connected to the positive pole of the diode group D1, a negative pole of the diode group D1 is connected to pole piece 1, and another negative pole of the diode group D1 is connected to a negative pole of the diode group D3;

[0037] The emitter of the optical coupler PH2 is connected to the positive electrode of the diode group D2, and the other negative electrode of the diode group D2 is connected to the pole piece 2;

[0038] The collector of the optocoupler PH3 is connected to the emitter of the optocoupler PH2, the emitter of the optocoupler PH3 is connected to the anode of the diode group D3, and the other cathode of the diode group D3 is connected to the pole piece three.

[0039] As a further solution of the present invention: the electrode includes pole piece 1, pole piece 2, pole piece 3, the signal processing circuit is a primary signal processing circuit, and the primary signal processing circuit includes transistor Q1, transistor Q3, transistor Q4, resistor R1, resistor R2, resistor R3, resistor R6, resistor R7, resistor R8, resistor R10, resistor R11, resistor R12;

[0040] The collector of the transistor Q1 in the primary signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the pole piece 1, the emitter of the transistor Q1 is connected to the ground G1, the base of the transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3 at the same time, the other end of the resistor R2 is connected to a negative electrode of the diode group D2, and the other end of the resistor R3 is connected to the ground G1;

[0041] The collector of the transistor Q3 in the primary signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the pole piece 2, the emitter of the transistor Q3 is connected to the ground G1, the base of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 at the same time, the other end of the resistor R7 is connected to a negative electrode of the diode group D3, and the other end of the resistor R8 is connected to the ground G1;

[0042] The collector of the transistor Q4 in the primary signal processing circuit is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the pole piece three, the emitter of the transistor Q4 is connected to the ground G1, the base of the transistor Q4 is simultaneously connected to one end of the resistor R11 and one end of the resistor R12, the other end of the resistor R11 is connected to a negative electrode of the diode group D2, and the other end of the resistor R12 is connected to the ground G1.

[0043] As a further solution of the present invention: Application of a pole piece polarity reversal circuit, characterized in that the pole piece polarity reversal circuit described in any one of claims 1-12 is applied to liquid level detection of liquid or foam, and to electrolysis.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention provides a method and circuit for reversing the polarity of a liquid or foam level detection electrode. The problem of the long-term unchanged polarity of a liquid level detection electrode in a single direction is solved by a electrode polarity reversal circuit. The polarity reversal can be controlled at any time or at a preset time to avoid damage to the electrode and increase the service life of the electrode. When the liquid level is not detected, the liquid level detection electrode is powered for a long time and the electrode is immersed in liquid, which will also reduce the service life of the electrode. The control signal makes the power supply of the electrode controllable, thereby increasing the service life of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a circuit framework diagram of the pole piece polarity reversal circuit disclosed in the embodiment.

[0047] Figure 2 It is a specific implementation circuit diagram of a two-pole-piece isolation type polarity reversal circuit in the pole piece polarity reversal circuit disclosed in the embodiment.

[0048] Figure 3 It is another specific implementation circuit diagram of the two-pole-piece isolation type polarity reversal circuit in the pole piece polarity reversal circuit disclosed in the embodiment.

[0049] Figure 4 It is a specific implementation circuit diagram of a two-pole-isolated multi-stage signal processing polarity reversal circuit in a pole-piece polarity reversal circuit disclosed in an embodiment.

[0050] Figure 5 It is a specific implementation circuit diagram of a two-pole non-isolated polarity reversal circuit in the pole piece polarity reversal circuit disclosed in the embodiment.

[0051] Figure 6 It is a specific implementation circuit diagram of an isolated polarity reversal circuit with more than two pole pieces in the pole piece polarity reversal circuit disclosed in the embodiment. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention; it is obvious that 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 creative work are within the scope of protection of the present invention.

[0053] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", and "connected" should be understood in a broad sense; for example, it can be a fixed connection, a detachable connection, or an integral connection, a mechanical connection, or an electrical connection, a direct connection, or an indirect connection through an intermediate medium, or the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] See also Figure 1 , a pole piece polarity reversal circuit, comprising a control signal circuit, a polarity reversal circuit, a detection signal output circuit, an electrode, a signal processing circuit and a power supply; the control signal circuit outputs two sets of control signals, the control signal circuit is electrically connected to the polarity reversal circuit, and the polarity reversal circuit comprises an isolated polarity reversal circuit or a non-isolated polarity reversal circuit; the polarity reversal circuit is electrically connected to the detection signal output circuit, and the detection signal output circuit is used to output the detection signal; the polarity reversal circuit is connected to the electrode, and the electrode comprises two sets of pole pieces or more than two sets of pole pieces, which are used to detect the liquid level of the liquid or foam; the electrode is connected to the signal processing circuit, and one pole piece is matched with one signal processing circuit, and the signal processing circuit comprises a primary signal processing circuit or a multi-stage signal processing circuit; the signal processing circuit is used to reduce the current flowing between the two pole pieces, thereby further improving the life of the pole piece;

[0055] The power supply is electrically connected to the control signal circuit, the polarity reversal circuit, and the detection signal output circuit to ensure power supply.

[0056] Embodiment 1, as Figure 2 As shown, the polarity reversal circuit is an isolated polarity reversal circuit, the isolated polarity reversal circuit includes an optocoupler PH1, an optocoupler PH2, an optocoupler PH3, a resistor 11, a resistor 12, a resistor 13, a diode D1 and a diode D2, the electrode includes a pole piece 1 and a pole piece 2, the signal processing circuit is a primary signal processing circuit, and the primary signal processing circuit includes a transistor Q1, a transistor Q3, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a resistor R7 and a resistor R8;

[0057] The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2;

[0058] The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2, and the anode of the optocoupler PH2 is connected to the power supply V2;

[0059] The power source V1 is connected to one end of the resistor R12, and the other end of the resistor R12 is simultaneously connected to the collector of the optocoupler PH1 and the collector of the optocoupler PH2;

[0060] The power supply V1 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to the anode of the optical coupler PH3, and the cathode of the optical coupler PH3 is connected to the collector of the optical coupler PH1 and the collector of the optical coupler PH2 at the same time; the emitter of the optical coupler PH3 is connected to the ground G2, and the collector of the optical coupler PH3 is connected to the detection signal output circuit for outputting the detection signal; the power supply V2 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the collector of the optical coupler PH3;

[0061] The emitter of the optical coupler PH1 is connected to the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to the pole piece 1, the emitter of the optical coupler PH2 is connected to the positive electrode of the diode D2, and the negative electrode of the diode D2 is connected to the pole piece 2;

[0062] The collector of the transistor Q1 in the primary signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the cathode of the diode D1, the emitter of the transistor Q1 is connected to the ground G1, the base of the transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3 at the same time, the other end of the resistor R2 is connected to the anode of the diode D2, and the other end of the resistor R3 is connected to the ground G1;

[0063] The collector of the transistor Q3 in the primary signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the cathode of the diode D2, the emitter of the transistor Q3 is connected to the ground G1, the base of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 at the same time, the other end of the resistor R7 is connected to the anode of the diode D1, and the other end of the resistor R8 is connected to the ground G1;

[0064] Control signal 1 outputs a low level, and control signal 2 maintains a high level, so that the power supply V1 forms a path 1 to the ground G1. If there is no liquid or foam between the electrode piece 1 and the electrode piece 2, only a small current flows from V1 through R12 / / (R11+PH3 input end), PH1 output end, R7, Q3 base, Q3 emitter to G1. At this time, the current flowing through the PH3 input end is not enough to turn on the PH3 output end, so that the detection signal output is maintained at a high level to achieve detection; if there is liquid or foam between the electrode piece 1 and the electrode piece 2, the power supply V1 forms a path 2 to the ground G1: from V1 through R12 / / (R11+PH3 input end), PH1 output end, D1, electrode piece 1, electrode piece 2, R6, Q3 collector, Q3 emitter to G1, the current in path 2 is amplified by the current in path 1 through Q3 to be sufficient to make the PH3 input end turn on the PH3 output end, so that the detection signal output is a low level to achieve detection. At this time, the potential of electrode piece 1 is higher than the potential of electrode piece 2.

[0065] Then the control signal 2 outputs a low level, and the control signal 1 maintains a high level, so that the power supply V1 forms a path 1 to the ground G1. If there is no liquid or foam between the electrode piece 1 and the electrode piece 2, only a small current flows from V1 through R12 / / (R11+PH3 input end), PH2 output end, R2, Q1 base, Q1 emitter to G1. At this time, the current flowing through the PH3 input end is not enough to turn on the PH3 output end, so that the detection signal output is maintained at a high level to achieve detection; if the electrode piece 1 and the electrode piece 2 are If there is liquid or foam between the two pieces, the power supply V1 forms a path 2 to the ground G1: from V1 through R12 / / (R11+PH3 input end), PH2 output end, D2, pole piece two, pole piece one, R1, Q1 collector, Q1 emitter to G1. The current in path 2 is amplified by the current in path 1 through Q1 to be sufficient to make the PH3 input end conduct to the PH3 output end, so that the detection signal output is a low level, realizing detection. At this time, the potential of pole piece two is higher than that of pole piece one, realizing the polarity reversal of the pole piece.

[0066] Embodiment 2: Figure 3 As shown, another implementation form; the polarity reversal circuit is an isolated polarity reversal circuit, the isolated polarity reversal circuit includes an optocoupler PH1, an optocoupler PH2, an optocoupler PH3, a transistor Q2, a resistor 11, a resistor 12, a resistor 13, a diode D1 and a diode D2, the electrode includes a pole piece 1 and a pole piece 2, the signal processing circuit is a primary signal processing circuit, and the primary signal processing circuit includes a transistor Q1, a transistor Q3, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a resistor R7 and a resistor R8;

[0067] The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2;

[0068] The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2, and the anode of the optocoupler PH2 is connected to the power supply V2;

[0069] The power source V1 is connected to one end of the resistor R12, and the other end of the resistor R12 is simultaneously connected to the base of the transistor Q2, the collector of the optocoupler PH1, and the collector of the optocoupler PH2;

[0070] The power supply V1 is connected to the emitter of the transistor Q2, the collector of the transistor Q2 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to the anode of the optical coupler PH3, and the cathode of the optical coupler PH3 is connected to the ground G1; the emitter of the optical coupler PH3 is connected to the ground G2, and the collector of the optical coupler PH3 is connected to the detection signal output circuit for outputting the detection signal; the power supply V2 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the collector of the optical coupler PH3;

[0071] The emitter of the optical coupler PH1 is connected to the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to the pole piece 1, the emitter of the optical coupler PH2 is connected to the positive electrode of the diode D2, and the negative electrode of the diode D2 is connected to the pole piece 2;

[0072] The collector of the transistor Q1 in the primary signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the cathode of the diode D1, the emitter of the transistor Q1 is connected to the ground G1, the base of the transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3 at the same time, the other end of the resistor R2 is connected to the anode of the diode D2, and the other end of the resistor R3 is connected to the ground G1;

[0073] The collector of the transistor Q3 in the primary signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the cathode of the diode D2, the emitter of the transistor Q3 is connected to the ground G1, the base of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 at the same time, the other end of the resistor R7 is connected to the anode of the diode D1, and the other end of the resistor R8 is connected to the ground G1;

[0074] Embodiment 3: Based on Embodiment 1, Figure 4 As shown, the signal processing circuit is a multi-stage signal processing circuit, and the multi-stage signal processing circuit includes transistor Q1, transistor Q2, transistor Q3, transistor Q4, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, capacitor C1, capacitor C2, capacitor C3 and capacitor C4;

[0075] The collector of the transistor Q1 in the multi-stage signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the negative electrode of the diode D1, the emitter of the transistor Q1 is simultaneously connected to the base of the transistor Q2, one end of the resistor R3, one end of the resistor R4, and one end of the capacitor C1, the other end of the resistor R4 and the other end of the capacitor C1 are both connected to the ground G1, the other end of the resistor R3 and one end of the resistor R2 are both connected to the base of the transistor Q1, the other end of the resistor R2 is connected to the positive electrode of the diode D2, the emitter of the transistor Q2 is connected to the ground G1, the collector of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the positive electrode of the diode D2, and the capacitor C2 is connected in parallel between the collector of the transistor Q2 and the emitter of the transistor Q2;

[0076] The collector of the transistor Q3 in the multi-stage signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the negative electrode of the diode D2, the emitter of the transistor Q3 is simultaneously connected to the base of the transistor Q4, one end of the resistor R8, one end of the resistor R9, and one end of the capacitor C3, the other end of the resistor R9 and the other end of the capacitor C3 are both connected to the ground G1, the other end of the resistor R8 and one end of the resistor R7 are both connected to the base of the transistor Q3, the other end of the resistor R7 is connected to the positive electrode of the diode D1, the emitter of the transistor Q4 is connected to the ground G1, the collector of the transistor Q4 is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the positive electrode of the diode D1, and the capacitor C4 is connected in parallel between the collector of the transistor Q4 and the emitter of the transistor Q4;

[0077] Control signal 1 outputs a low level, and control signal 2 maintains a high level, so that the power supply V1 forms a path 1 to the ground G1. If there is no liquid or foam between the electrode piece 1 and the electrode piece 2, only a small current flows from V1 through R12 / / (R11+PH3 input end), PH1 output end, R7, Q3 base, Q3 emitter, R9 to G1. At this time, the current flowing through the PH3 input end is not enough to turn on the PH3 output end, so that the detection signal output is maintained at a high level to achieve detection; if the electrode piece If there is liquid or foam between electrode one and electrode two, path 2 is formed from power supply V1 to ground G1: from V1 through R12 / / (R11+PH3 input), PH1 output, D1, electrode one, electrode two, R6, Q3 collector, Q3 emitter, R9 to G1. The current in path 2 is amplified by the current in path 1 through Q3 to be sufficient to make PH3 input conduct to PH3 output, so that the detection signal output is low level, realizing detection. At this time, the potential of electrode one is higher than that of electrode two.

[0078] Then the control signal 2 outputs a low level, and the control signal 1 maintains a high level, so that the power supply V1 forms a path 1 to the ground G1. If there is no liquid or foam between the electrode piece 1 and the electrode piece 2, only a small current flows from V1 through R12 / / (R11+PH3 input end), PH2 output end, R2, Q1 base, Q1 emitter, R4 to G1. At this time, the current flowing through the PH3 input end is not enough to turn on the PH3 output end, so that the detection signal output is maintained at a high level to achieve detection; if the electrode piece 1 and the electrode piece 2 are If there is liquid or foam between the two pieces, the power supply V1 forms a path 2 to the ground G1: from V1 through R12 / / (R11+PH3 input end), PH2 output end, D2, pole piece two, pole piece one, R1, Q1 collector, Q1 emitter, R4 to G1. The current in path 2 is amplified by the current in path 1 through Q1 to be sufficient to make the PH3 input end conduct to the PH3 output end, so that the detection signal output is a low level, realizing detection. At this time, the potential of pole piece two is higher than that of pole piece one, realizing the polarity reversal of the pole piece.

[0079] Embodiment 4: Based on Embodiment 1, Figure 5 As shown, the polarity reversal circuit is a non-isolated polarity reversal circuit, and the non-isolated polarity reversal circuit includes transistor Q5, transistor Q6, transistor Q7, resistor 11, diode D1 and diode D2;

[0080] The control signal 1 output by the control signal circuit is connected to the base of the transistor Q6, the emitter of the transistor Q6 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the pole piece 1;

[0081] The control signal 2 output by the control signal circuit is connected to the base of the transistor Q5, the emitter of the transistor Q5 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the pole piece 2;

[0082] The power source V1 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to the collector of the transistor Q5 and the collector of the transistor Q6 at the same time;

[0083] The power source V1 is connected to the emitter of the transistor Q7, and the collector of the transistor Q7 is connected to the detection signal output circuit for outputting the detection signal;

[0084] Embodiment 5: Figure 6 As shown, the electrode includes more than two sets of pole pieces, and this embodiment includes three sets of pole pieces;

[0085] The polarity reversal circuit is an isolated polarity reversal circuit, the isolated polarity reversal circuit includes an optocoupler PH1, an optocoupler PH2, an optocoupler PH3, an optocoupler PH4, a resistor 14, a resistor 15, a resistor 16, a diode group D1, a diode group D2 and a diode group D3, the electrode includes a pole piece 1, a pole piece 2 and a pole piece 3, the signal processing circuit is a primary signal processing circuit, the primary signal processing circuit includes a transistor Q1, a transistor Q3, a transistor Q4, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a resistor R7, a resistor R8, a resistor R10, a resistor R11 and a resistor R12;

[0086] The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2;

[0087] The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2 and the cathode of the optocoupler PH3, and the anode of the optocoupler PH2 and the anode of the optocoupler PH3 are connected to the power supply V2;

[0088] The power source V1 is connected to one end of the resistor R15, and the other end of the resistor R15 is connected to the collector of the optical coupler PH1 and the collector of the optical coupler PH2 at the same time;

[0089] The power supply V1 is connected to one end of the resistor R14, the other end of the resistor R14 is connected to the anode of the optical coupler PH4, and the cathode of the optical coupler PH4 is connected to the collector of the optical coupler PH1 and the collector of the optical coupler PH2 at the same time; the emitter of the optical coupler PH4 is connected to the ground G2, and the collector of the optical coupler PH4 is connected to the detection signal output circuit for outputting the detection signal; the power supply V2 is connected to one end of the resistor R16, and the other end of the resistor R16 is connected to the collector of the optical coupler PH4;

[0090] The emitter of the optical coupler PH1 is connected to the positive electrode of the diode group D1, one cathode of the diode group D1 is connected to the pole piece 1, and the other cathode of the diode group D1 is connected to one cathode of the diode group D3;

[0091] The collector of the transistor Q1 in the primary signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the pole piece 1, the emitter of the transistor Q1 is connected to the ground G1, the base of the transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3 at the same time, the other end of the resistor R2 is connected to a negative electrode of the diode group D2, and the other end of the resistor R3 is connected to the ground G1;

[0092] The emitter of the optical coupler PH2 is connected to the positive electrode of the diode group D2, and the other negative electrode of the diode group D2 is connected to the pole piece 2;

[0093] The collector of the transistor Q3 in the primary signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the pole piece 2, the emitter of the transistor Q3 is connected to the ground G1, the base of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 at the same time, the other end of the resistor R7 is connected to a negative electrode of the diode group D3, and the other end of the resistor R8 is connected to the ground G1;

[0094] The collector of the optocoupler PH3 is connected to the emitter of the optocoupler PH2, the emitter of the optocoupler PH3 is connected to the positive electrode of the diode group D3, and the other negative electrode of the diode group D3 is connected to the pole piece 3;

[0095] The collector of the transistor Q4 in the primary signal processing circuit is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the pole piece three, the emitter of the transistor Q4 is connected to the ground G1, the base of the transistor Q4 is connected to one end of the resistor R11 and one end of the resistor R12 at the same time, the other end of the resistor R11 is connected to a negative electrode of the diode group D2, and the other end of the resistor R12 is connected to the ground G1;

[0096] By gradually adding pole pieces and adding corresponding polarity reversal circuits and signal processing circuits, it is convenient to control multiple pole pieces, which is beneficial to reversing the polarity of the pole pieces, increasing safety, and facilitating the use of the device.

[0097] The present invention provides a method and circuit for reversing the polarity of a liquid or foam level detection electrode. When the polarity of the liquid level detection electrode remains unchanged in one direction for a long time, the service life of the electrode will be reduced. This problem is solved by a polarity reversal circuit of the electrode. When the liquid level is not detected, the liquid level detection electrode is powered for a long time and the electrode is immersed in liquid, the service life of the electrode will also be reduced. The control signal makes the power supply of the electrode controllable, thereby increasing the service life of the electrode.

[0098] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive from any point of view. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention, and any reference numerals in the claims should not be considered as limiting the claims involved.

[0099] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A pole piece polarity reversal circuit, characterized in that: It includes a control signal circuit, a polarity reversal circuit, a detection signal output circuit, electrodes, a signal processing circuit and a power supply; the control signal circuit outputs two groups of control signals, the control signal circuit is electrically connected to the polarity reversal circuit, and the polarity reversal circuit includes an isolated polarity reversal circuit or a non-isolated polarity reversal circuit; the polarity reversal circuit is electrically connected to the detection signal output circuit, and the detection signal output circuit is used to output the detection signal; the polarity reversal circuit is connected to the electrode, and the electrode includes two groups of pole pieces or more than two groups of pole pieces, which are used to detect the liquid level of liquid or foam; the electrode is connected to the signal processing circuit, and one pole piece is matched with one signal processing circuit, and the signal processing circuit includes a primary signal processing circuit or a multi-stage signal processing circuit; the signal processing circuit is used to reduce the current flowing between the two pole pieces; The power supply is electrically connected to the control signal circuit, the polarity reversal circuit, and the detection signal output circuit.

2. The pole piece polarity reversal circuit according to claim 1, characterized in that: The polarity reversal circuit is an isolated polarity reversal circuit, and the isolated polarity reversal circuit includes an optical coupler PH1, an optical coupler PH2, an optical coupler PH3, a resistor 11, a resistor 12, a resistor 13, a diode D1 and a diode D2; The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2; The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2, and the anode of the optocoupler PH2 is connected to the power supply V2; The power source V1 is connected to one end of the resistor R12, and the other end of the resistor R12 is simultaneously connected to the collector of the optocoupler PH1 and the collector of the optocoupler PH2; The power supply V1 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to the anode of the optical coupler PH3, the cathode of the optical coupler PH3 is connected to the collector of the optical coupler PH1 and the collector of the optical coupler PH2 at the same time; the emitter of the optical coupler PH3 is connected to the ground G2, and the collector of the optical coupler PH3 is connected to the detection signal output circuit for outputting the detection signal; The power source V2 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the collector of the optical coupler PH3.

3. The pole piece polarity reversal circuit according to claim 1, characterized in that: The polarity reversal circuit is an isolated polarity reversal circuit, and the isolated polarity reversal circuit includes an optical coupler PH1, an optical coupler PH2, an optical coupler PH3, a transistor Q2, a resistor 11, a resistor 12, a resistor 13, a diode D1 and a diode D2; The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2; The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2, and the anode of the optocoupler PH2 is connected to the power supply V2; The power source V1 is connected to one end of the resistor R12, and the other end of the resistor R12 is simultaneously connected to the base of the transistor Q2, the collector of the optocoupler PH1, and the collector of the optocoupler PH2; The power supply V1 is connected to the emitter of the transistor Q2, the collector of the transistor Q2 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to the anode of the optical coupler PH3, and the cathode of the optical coupler PH3 is connected to the ground G1; the emitter of the optical coupler PH3 is connected to the ground G2, and the collector of the optical coupler PH3 is connected to the detection signal output circuit for outputting the detection signal; The power source V2 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the collector of the optical coupler PH3.

4. The pole piece polarity reversal circuit according to claim 2 or 3, characterized in that: The electrodes include two groups of pole pieces, the electrodes include pole piece one and pole piece two; the emitter of the optical coupler PH1 is connected to the positive pole of the diode D1, the negative pole of the diode D1 is connected to pole piece one, the emitter of the optical coupler PH2 is connected to the positive pole of the diode D2, and the negative pole of the diode D2 is connected to pole piece two.

5. The pole piece polarity reversal circuit according to claim 4, characterized in that: The signal processing circuit is a primary signal processing circuit, and the primary signal processing circuit includes a transistor Q1, a transistor Q3, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a resistor R7 and a resistor R8; The collector of the transistor Q1 in the primary signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the cathode of the diode D1, the emitter of the transistor Q1 is connected to the ground G1, the base of the transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3 at the same time, the other end of the resistor R2 is connected to the anode of the diode D2, and the other end of the resistor R3 is connected to the ground G1; The collector of the transistor Q3 in the primary signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the cathode of the diode D2, the emitter of the transistor Q3 is connected to the ground G1, the base of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 at the same time, the other end of the resistor R7 is connected to the anode of the diode D1, and the other end of the resistor R8 is connected to the ground G1.

6. The pole piece polarity reversal circuit according to claim 4, characterized in that: The signal processing circuit is a multi-stage signal processing circuit, which includes transistor Q1, transistor Q2, transistor Q3, transistor Q4, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, capacitor C1, capacitor C2, capacitor C3 and capacitor C4; The collector of the transistor Q1 in the multi-stage signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the negative electrode of the diode D1, the emitter of the transistor Q1 is simultaneously connected to the base of the transistor Q2, one end of the resistor R3, one end of the resistor R4, and one end of the capacitor C1, the other end of the resistor R4 and the other end of the capacitor C1 are both connected to the ground G1, the other end of the resistor R3 and one end of the resistor R2 are both connected to the base of the transistor Q1, the other end of the resistor R2 is connected to the positive electrode of the diode D2, the emitter of the transistor Q2 is connected to the ground G1, the collector of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the positive electrode of the diode D2, and the capacitor C2 is connected in parallel between the collector of the transistor Q2 and the emitter of the transistor Q2; The collector of the transistor Q3 in the multi-stage signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the cathode of the diode D2, the emitter of the transistor Q3 is simultaneously connected to the base of the transistor Q4, one end of the resistor R8, one end of the resistor R9, and one end of the capacitor C3, the other end of the resistor R9 and the other end of the capacitor C3 are both connected to the ground G1, the other end of the resistor R8 and one end of the resistor R7 are both connected to the base of the transistor Q3, the other end of the resistor R7 is connected to the anode of the diode D1, the emitter of the transistor Q4 is connected to the ground G1, the collector of the transistor Q4 is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the anode of the diode D1, and the capacitor C4 is connected in parallel between the collector of the transistor Q4 and the emitter of the transistor Q4.

7. The pole piece polarity reversal circuit according to claim 1, characterized in that: The polarity reversal circuit is a non-isolated polarity reversal circuit, which includes transistor Q5, transistor Q6, transistor Q7, resistor 11, diode D1 and diode D2; the electrode includes two sets of pole pieces, the electrode includes pole piece 1 and pole piece 2; The control signal 1 output by the control signal circuit is connected to the base of the transistor Q6, the emitter of the transistor Q6 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the pole piece 1; The control signal 2 output by the control signal circuit is connected to the base of the transistor Q5, the emitter of the transistor Q5 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the pole piece 2; The power source V1 is connected to one end of the resistor R11, and the other end of the resistor R11 is simultaneously connected to the collector of the transistor Q5 and the collector of the transistor Q6; The power source V1 is connected to the emitter of the transistor Q7, and the collector of the transistor Q7 is connected to the detection signal output circuit for outputting the detection signal; The electrodes are connected to a signal processing circuit.

8. The pole piece polarity reversal circuit according to claim 7, characterized in that: The signal processing circuit is a primary signal processing circuit, and the primary signal processing circuit includes a transistor Q1, a transistor Q3, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a resistor R7 and a resistor R8; The collector of the transistor Q1 in the primary signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the cathode of the diode D1, the emitter of the transistor Q1 is connected to the ground G1, the base of the transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3 at the same time, the other end of the resistor R2 is connected to the anode of the diode D2, and the other end of the resistor R3 is connected to the ground G1; The collector of the transistor Q3 in the primary signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the cathode of the diode D2, the emitter of the transistor Q3 is connected to the ground G1, the base of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 at the same time, the other end of the resistor R7 is connected to the anode of the diode D1, and the other end of the resistor R8 is connected to the ground G1.

9. The pole piece polarity reversal circuit according to claim 7, characterized in that: The signal processing circuit is a multi-stage signal processing circuit, which includes transistor Q1, transistor Q2, transistor Q3, transistor Q4, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, capacitor C1, capacitor C2, capacitor C3 and capacitor C4; The collector of the transistor Q1 in the multi-stage signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the negative electrode of the diode D1, the emitter of the transistor Q1 is simultaneously connected to the base of the transistor Q2, one end of the resistor R3, one end of the resistor R4, and one end of the capacitor C1, the other end of the resistor R4 and the other end of the capacitor C1 are both connected to the ground G1, the other end of the resistor R3 and one end of the resistor R2 are both connected to the base of the transistor Q1, the other end of the resistor R2 is connected to the positive electrode of the diode D2, the emitter of the transistor Q2 is connected to the ground G1, the collector of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the positive electrode of the diode D2, and the capacitor C2 is connected in parallel between the collector of the transistor Q2 and the emitter of the transistor Q2; The collector of the transistor Q3 in the multi-stage signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the cathode of the diode D2, the emitter of the transistor Q3 is simultaneously connected to the base of the transistor Q4, one end of the resistor R8, one end of the resistor R9, and one end of the capacitor C3, the other end of the resistor R9 and the other end of the capacitor C3 are both connected to the ground G1, the other end of the resistor R8 and one end of the resistor R7 are both connected to the base of the transistor Q3, the other end of the resistor R7 is connected to the anode of the diode D1, the emitter of the transistor Q4 is connected to the ground G1, the collector of the transistor Q4 is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the anode of the diode D1, and the capacitor C4 is connected in parallel between the collector of the transistor Q4 and the emitter of the transistor Q4.

10. The pole piece polarity reversal circuit according to claim 1, characterized in that: The polarity reversal circuit is an isolated polarity reversal circuit, which includes an optical coupler PH1, an optical coupler PH2, an optical coupler PH3, an optical coupler PH4, a resistor 14, a resistor 15, a resistor 16, a diode group D1, a diode group D2 and a diode group D3; the electrode includes more than two groups of pole pieces, and the electrode includes pole piece 1, pole piece 2 and pole piece 3; The control signal 1 output by the control signal circuit is connected to the cathode of the optocoupler PH1, and the anode of the optocoupler PH1 is connected to the power supply V2; The control signal 2 output by the control signal circuit is connected to the cathode of the optocoupler PH2 and the cathode of the optocoupler PH3, and the anode of the optocoupler PH2 and the anode of the optocoupler PH3 are connected to the power supply V2; The power source V1 is connected to one end of the resistor R15, and the other end of the resistor R15 is connected to the collector of the optical coupler PH1 and the collector of the optical coupler PH2 at the same time; The power supply V1 is connected to one end of the resistor R14, the other end of the resistor R14 is connected to the anode of the optical coupler PH4, the cathode of the optical coupler PH4 is connected to the collector of the optical coupler PH1 and the collector of the optical coupler PH2 at the same time; the emitter of the optical coupler PH4 is connected to the ground G2, and the collector of the optical coupler PH4 is connected to the detection signal output circuit for outputting the detection signal; The power source V2 is connected to one end of the resistor R16, and the other end of the resistor R16 is connected to the collector of the optical coupler PH4.

11. The pole piece polarity reversal circuit according to claim 10, characterized in that: The emitter of the optical coupler PH1 is connected to the positive electrode of the diode group D1, one cathode of the diode group D1 is connected to the pole piece 1, and the other cathode of the diode group D1 is connected to one cathode of the diode group D3; The emitter of the optical coupler PH2 is connected to the positive electrode of the diode group D2, and the other negative electrode of the diode group D2 is connected to the pole piece 2; The collector of the optocoupler PH3 is connected to the emitter of the optocoupler PH2, the emitter of the optocoupler PH3 is connected to the anode of the diode group D3, and the other cathode of the diode group D3 is connected to the pole piece three.

12. The pole piece polarity reversal circuit according to claim 11, characterized in that: The signal processing circuit is a primary signal processing circuit, which includes transistor Q1, transistor Q3, transistor Q4, resistor R1, resistor R2, resistor R3, resistor R6, resistor R7, resistor R8, resistor R10, resistor R11, and resistor R12; The collector of the transistor Q1 in the primary signal processing circuit is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the pole piece 1, the emitter of the transistor Q1 is connected to the ground G1, the base of the transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3 at the same time, the other end of the resistor R2 is connected to a negative electrode of the diode group D2, and the other end of the resistor R3 is connected to the ground G1; The collector of the transistor Q3 in the primary signal processing circuit is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the pole piece 2, the emitter of the transistor Q3 is connected to the ground G1, the base of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 at the same time, the other end of the resistor R7 is connected to a negative electrode of the diode group D3, and the other end of the resistor R8 is connected to the ground G1; The collector of the transistor Q4 in the primary signal processing circuit is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the pole piece three, the emitter of the transistor Q4 is connected to the ground G1, the base of the transistor Q4 is simultaneously connected to one end of the resistor R11 and one end of the resistor R12, the other end of the resistor R11 is connected to a negative electrode of the diode group D2, and the other end of the resistor R12 is connected to the ground G1.

13. Application of the pole piece polarity reversal circuit, characterized in that: The pole piece polarity reversal circuit described in any one of claims 1 to 12 is applied to liquid level detection of liquid or foam, or to electrolysis.

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