CN112595384A - Liquid level detection device and implementation method - Google Patents

Abstract

The invention relates to a liquid level detection device and a realization method thereof, comprising a shell, a main board, an optical probe, a sealing rubber ring and a potting material, wherein when the optical probe is positioned in an air environment, an infrared emission tube D1 is formed to emit infrared rays, the optical probe performs twice total reflection, an infrared detection tube Q1 is communicated with an optical passage of the infrared rays, and the infrared rays are emitted after being received by an infrared emission tube D1; when the optical probe is in the liquid to be detected, the infrared emission tube D1 emits infrared rays, the optical probe refracts or transmits for one time, the infrared detection tube Q1 is not communicated with the optical path of the infrared rays, the infrared rays cannot be received, and liquid level detection is realized. The liquid level detection device has the effect of achieving the purpose of high-reliability liquid level detection.

Description

Liquid level detection device and implementation method

Technical Field

The invention relates to a liquid level detection device and an implementation method thereof, which are used for liquid level detection of various liquid storage devices.

Background

Liquid level switches are widely used on various liquid storage devices to detect the liquid level height of the liquid storage devices. The liquid level switch is a pure mechanical switch or an electromechanical hybrid switch from a float switch to a magnetic switch and then to a flap type photoelectric switch. Due to the introduction of a mechanical structure, the structure of the switch is complex, the reliability of long-term work is low, once the mechanical structure is clamped, the liquid level switch fails, the liquid level switch signal is mistakenly reported or is not reported, and great potential safety hazards are brought to the whole liquid storage device. Therefore, independent research and development of a simple and reliable liquid level detection device is an important issue to be solved urgently by technical staff.

Disclosure of Invention

In view of the problems in the prior art, the invention provides a liquid level detection device which can conveniently detect whether a liquid level is contacted with the liquid level, and the specific technical scheme is that the liquid level detection device comprises a shell, a main board, an optical probe, a sealing rubber ring and a potting material, and is characterized in that: the shell is a cylindrical cavity, the main board consists of a circuit board, an infrared emission tube D1, an infrared detection tube Q1, an external power supply line, a common ground wire, a signal output line and a protective tube F1, the infrared emission tube D1, the infrared detection tube Q1, a voltage stabilizing capacitor C1, a current limiting resistor R1 and a voltage dividing resistor R2 protective tube F1 are fixed on the front end face of the circuit board, the external power supply line, the common ground wire and the signal output line are welded with the circuit board and are arranged on the rear end face of the circuit board, the optical probe is a transparent conical total reflection prism, the diameter of the bottom face of the conical body is smaller than the inner diameter of the sealing rubber ring, the bottom face of the optical probe is provided with an emission tube cavity and a detection tube cavity, the positions and the sizes of the emission tube D1 and the infrared detection tube Q1 of the main board are matched, the optical central axis probe, the infrared emission tube D1 and the infrared detection tube Q1 are arranged in parallel, the sealing, the main board is arranged in the shell, the front end face of the circuit board of the main board is tightly propped against the sealing gasket, the infrared transmitting tube D1 and the infrared detecting tube Q1 are respectively inserted into the transmitting tube cavity and the detecting tube cavity 3-3 of the optical probe, and the encapsulating material is poured into the shell and fixed; the circuit connection is that +24V of an external power supply line is connected with one end of a protective tube F1, the other end of the protective tube F1 is connected with the anode of a voltage stabilizing capacitor C1, a current limiting resistor R1, a voltage dividing resistor R2 and the power supply end of an infrared detection tube Q1, the other end of the current limiting resistor R1 is connected with the anode of an infrared emission tube D1, the signal output end of the infrared detection tube is connected with a voltage dividing resistor R3, the other end of the voltage dividing resistor R2 is connected with a signal output line OUT and the drain of a signal isolation transistor Q2, the other end of the voltage dividing resistor R3 is connected with a voltage dividing resistor R4 and the gate of a signal isolation transistor Q2, the cathode of a voltage stabilizing capacitor C1, the cathode of the infrared emission tube D1, the grounding end of the infrared detection tube Q1, the source of the signal isolation.

The implementation method comprises the following steps that firstly, an external power supply +24V power supply is connected with an external power supply line + 24V; connecting the detection end of an external signal acquisition system with a signal output line OUT, connecting an external public ground wire with a ground wire GND of a main board, and secondly, after the device is connected with a +24V external power supply, and after the +24V external power supply is stabilized by a protective tube F1 and a voltage stabilizing capacitor C1, supplying power to a circuit board to enable an infrared emission tube D1 to continuously output infrared rays; thirdly, when the optical probe is not immersed in the liquid level and is in an air environment, the optical probe is in a total reflection state, infrared rays emitted by the infrared emission tube D1 are reflected twice by the optical probe and then received by the infrared detection tube Q1, the output end of the infrared detection tube Q1 outputs a high level, the high level signal is divided by the voltage dividing resistor R3 and the voltage dividing resistor R4, the signal isolation transistor Q2 is conducted, and the signal output end OUT outputs a low level; fourthly, when the optical probe (3) is immersed in the liquid level, the optical probe is in a transmission/refraction state, at the moment, when infrared rays emitted by the infrared emission tube D1 reach the joint surface of the outer surface of the optical probe and liquid, the infrared rays are refracted, the infrared detection tube Q1 cannot receive the infrared rays, the output end of the infrared detection tube Q1 outputs a low level, and after the low level signal is subjected to voltage division by the voltage division resistor R3 and the voltage division resistor R4, the signal isolation transistor Q2 is cut off, and the signal output line OUT outputs a high level; fifthly, detecting the position of the liquid level according to the voltage on a signal output line OUT on the device, wherein when the signal output line OUT outputs a low level, the device does not detect the liquid level; when the signal output line OUT outputs a high level, it indicates that the device has detected a liquid level.

The invention has the technical effects that a mode of working in a reflecting state in an air environment and working in a refracting or transmitting state in a liquid environment is constructed by applying the principle of a total reflection prism, and the aim of high-reliability liquid level detection is fulfilled by matching with extremely simple electronic components.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a cross-sectional view of the structure of the present invention;

FIG. 3 is an exploded view of the present invention;

FIG. 4 is a circuit schematic of the present invention;

FIG. 5 is an optical schematic diagram of the present invention with air outside;

fig. 6 is an optical schematic diagram of the present invention with liquid outside.

Detailed Description

The invention will be further explained with reference to the drawings.

The structure of the invention is formed by the following principles:

as shown in fig. 5 and 6, when the optical probe 3 is in the air environment, the infrared emitting tube D1 is configured to emit infrared rays, the optical probe 3 performs total reflection twice, the infrared detecting tube Q1 is communicated with the optical path of the infrared rays, and the infrared emitting tube D1 is received to emit infrared rays; when the optical probe 3 is in the liquid to be detected, the infrared emission tube D1 emits infrared rays, the optical probe 3 refracts or transmits for one time, the infrared detection tube Q1 is not communicated with the optical path of the infrared rays, and the infrared rays cannot be received, so that whether the optical probe contacts the liquid level is detected according to the principle.

As shown in fig. 1 to 4, a liquid level detecting device comprises a housing 1, a main board 2, an optical probe 3, a sealing rubber ring 4 and a potting material 5, wherein the infrared transmitting tube D1 is OP133, the infrared detecting tube Q1 is OPL820,

the shell 1 is a cylindrical cavity, the main board 2 is composed of a circuit board 2-1, an infrared emission tube D1, an infrared detection tube Q1, an external power supply line 2-4, a common ground wire 2-5, a signal output line 2-6 and a protective tube F1, the infrared emission tube D1, the infrared detection tube Q1, a voltage stabilizing capacitor C1, a current limiting resistor R1 and a voltage dividing resistor R2 protective tube F1 are fixed on the front end face of the circuit board 2-1, the external power supply line 2-4, the common ground wire 2-5 and the signal output line 2-6 are welded with the circuit board 2-1 and are placed on the rear end face of the circuit board 2-1, the optical probe 3 is a transparent conical total reflection prism, the diameter of the bottom face of the conical body is smaller than the inner diameter of the sealing rubber ring 4, the emission tube cavity 3-2 and the detection tube cavity 3-, The size of the optical probe is matched with that of an infrared emission tube D1 and an infrared detection tube Q1 of a mainboard 2, the optical probe 3, the infrared emission tube D1 and the infrared detection tube Q1 are arranged in parallel, a sealing rubber ring 4 is sleeved on the optical probe 3 and is arranged on an optical probe mounting hole 1-1 in a shell 1 together, the mainboard 2 is arranged in the shell (1), the front end face of a circuit board 2-1 of the mainboard (2) is tightly propped against the sealing rubber ring 4, the infrared emission tube D1 and the infrared detection tube Q1 are respectively inserted into an emission tube cavity 3-2 and a detection tube cavity 3-3 of the optical probe 3, and an encapsulating material 5 is filled in the shell 1 for fixation; the circuit connection is that +24V of an external power supply line 2-4 is connected with one end of a protective tube F1, the other end of the protective tube F1 is connected with the anode of a voltage stabilizing capacitor C1, the power supply ends of a current limiting resistor R1, a voltage dividing resistor R2 and an infrared detection tube Q1, the other end of the current limiting resistor R1 is connected with the anode of an infrared emission tube D1, the signal output end of the infrared detection tube is connected with a voltage dividing resistor R3, the other end of the voltage dividing resistor R2 is connected with a signal output line OUT and the drain of a signal isolation transistor Q2, the other end of the voltage dividing resistor R3 is connected with a voltage dividing resistor R4 and the gate of a signal isolation transistor Q2, the cathode of a voltage stabilizing capacitor C1, the cathode of the infrared emission tube D1, the grounding end of the infrared detection tube Q1, the source of the signal isolation.

The method comprises the following steps:

firstly, connecting an external power supply +24V power supply with an external power supply line + 24V; the detection end of the external signal acquisition system is connected with a signal output line OUT, an external common ground wire is connected with a ground wire GND of the main board,

secondly, after the device is connected with a +24V external power supply, the +24V external power supply supplies power to the circuit board 2-1 after the voltage of the protective tube F1 and the voltage stabilizing capacitor C1 is stabilized, so that the infrared emission tube D1 continuously outputs infrared rays;

thirdly, when the optical probe 3 is not immersed in the liquid level and is in an air environment, the optical probe 3 is in a full reflection state, infrared rays emitted by the infrared emission tube D1 are reflected by the optical probe 3 twice and then received by the infrared detection tube Q1, the output end of the infrared detection tube Q1 outputs a high level, the high level signal is divided by the voltage dividing resistor R3 and the voltage dividing resistor R4, the signal isolation transistor Q2 is conducted, and the signal output end OUT outputs a low level;

fourthly, after the optical probe 3 is immersed in the liquid level, the optical probe 3 is in a transmission/refraction state, at the moment, when the infrared ray emitted by the infrared emission tube D1 reaches the interface between the outer surface of the optical probe 3 and the liquid, the infrared ray is refracted, the infrared detection tube Q1 cannot receive the infrared ray, the output end of the infrared detection tube Q1 outputs a low level, the low level signal is subjected to voltage division by the voltage division resistor R3 and the voltage division resistor R4, the signal isolation transistor Q2 is cut off, and the signal output line OUT outputs a high level;

fifthly, detecting the position of the liquid level according to the voltage on a signal output line OUT on the device, wherein when the signal output line OUT outputs a low level, the device does not detect the liquid level; when the signal output line OUT outputs a high level, it indicates that the device has detected a liquid level.

Claims (2)

1. The utility model provides a liquid level detection device, includes casing (1), mainboard (2), optical probe (3), rubber gasket (4), potting material (5), its characterized in that: the shell (1) is a cylindrical cavity with a bottom, an optical probe mounting hole (1-1) with a through hole is arranged in the bottom cylinder, the diameter of the mounting hole (1-1) is smaller than the inner diameter of the sealing rubber ring (4), the mainboard (2) is composed of a circuit board (2-1), an infrared emission tube D1, an infrared detection tube Q1, an external power supply line (2-4), a public ground wire (2-5), a signal output line (2-6) and a protective tube F1, the infrared emission tube D1, the infrared detection tube Q1, a voltage stabilizing capacitor C1, a current limiting resistor R1 and a voltage dividing resistor R2, the protective tube F1 is fixed on the front end face of the circuit board (2-1), the external power supply line (2-4), the public ground wire (2-5), the signal output line (2-6) and the circuit board (2-1) are welded and arranged on the back end face of the circuit board, the optical probe (3) is a transparent conical total reflection prism, the diameter of the bottom surface of the conical body is larger than the inner diameter of the sealing rubber ring (4), a transmitting tube cavity (3-2) and a detecting tube cavity (3-3) are arranged at the bottom surface of the optical probe (3), the positions and the sizes of the optical probe and the detecting tube cavity are matched with an infrared transmitting tube D1 and an infrared detecting tube Q1 of the main board (2), the optical probe (3), the infrared transmitting tube D1 and the infrared detecting tube Q1 are arranged in parallel, the sealing rubber ring (4) is sleeved on the optical probe (3) and is arranged on an optical probe mounting hole (1-1) in the shell (1), the main board (2) is arranged in the shell (1), the front end face of a circuit board (2-1) of the main board (2) is tightly pressed on the sealing rubber ring (4), the infrared transmitting tube D1 and the infrared detecting tube Q1 are respectively inserted into the transmitting tube cavity (3-2) of the optical probe (3), In the cavity 3-3 of the detection tube, the potting material (5) is poured into the shell (1) and fixed; the circuit connection is that +24V of an external power supply line (2-4) is connected with one end of a protective tube F1, the other end of the protective tube F1 is connected with the anode of a voltage stabilizing capacitor C1, the power supply end of a current limiting resistor R1, a voltage dividing resistor R2 and an infrared detection tube Q1, the other end of the current limiting resistor R1 is connected with the anode of an infrared emission tube D1, the signal output end of the infrared detection tube is connected with a voltage dividing resistor R3, the other end of the voltage dividing resistor R2 is connected with a signal output line OUT and the drain of a signal isolation transistor Q2, the other end of the voltage dividing resistor R3 is connected with a voltage dividing resistor R4 and the gate of a signal isolation transistor Q2, the cathode of a voltage stabilizing capacitor C1, the cathode of the infrared emission tube D1, the grounding end of the infrared detection tube Q1, the source of the signal isolation.

2. A method for implementing a liquid level detection device according to claim 1, comprising the following steps: firstly, connecting an external power supply +24V power supply with an external power supply line + 24V; the detection end of the external signal acquisition system is connected with a signal output line OUT, an external common ground wire is connected with a ground wire GND of the main board,

secondly, after the device is connected with a +24V external power supply, the +24V external power supply supplies power to the circuit board (2-1) after the voltage of the protective tube F1 and the voltage stabilizing capacitor C1 is stabilized, so that the infrared emission tube D1 continuously outputs infrared rays;

thirdly, when the optical probe (3) is not immersed in the liquid level and is in an air environment, the optical probe (3) is in a full reflection state, infrared rays emitted by the infrared emission tube D1 are reflected twice by the optical probe (3) and then received by the infrared detection tube Q1, the output end of the infrared detection tube Q1 outputs a high level, the high level signal is subjected to voltage division by the voltage division resistor R3 and the voltage division resistor R4, the signal isolation transistor Q2 is conducted, and the signal output end OUT outputs a low level;

fourthly, when the optical probe (3) is immersed in the liquid level, the optical probe (3) is in a transmission/refraction state, at the moment, when the infrared ray emitted by the infrared emission tube D1 reaches the joint surface of the outer surface of the optical probe (3) and the liquid, the infrared ray is refracted, the infrared detection tube Q1 cannot receive the infrared ray, the output end of the infrared detection tube Q1 outputs a low level, the low level signal is subjected to voltage division by the voltage division resistor R3 and the voltage division resistor R4, the signal isolation transistor Q2 is cut off, and the signal output line OUT outputs a high level;

fifthly, detecting the position of the liquid level according to the voltage on a signal output line OUT on the device, wherein when the signal output line OUT outputs a low level, the device does not detect the liquid level; when the signal output line OUT outputs a high level, it indicates that the device has detected a liquid level.

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