A liquid leakage detection alarm device

Abstract

A kind of liquid leakage detection alarm device, including thermistor R8, thermistor R9, operational amplifier U1A, operational amplifier U1B, triode Q1 and single-chip microcomputer IC1;Input DC and supply voltage VCC3 are divided into two ways, one way is connected with operational amplifier U1A by thermistor R8 and first voltage dividing circuit, another way is connected with operational amplifier U1A by thermistor R9 and second voltage dividing circuit, the output of operational amplifier U1A is connected to operational amplifier U1B, the level of the output of operational amplifier U1B is controlled by voltage division whether triode Q1 is turned on, and single-chip microcomputer IC1 carries out normal work signal or alarm signal output according to the conduction of triode Q1.This device replaces the original leakage detection sensor by thermistor, principle is easy to understand and convenient for operator to realize, circuit structure is easy to realize, and can be widely used.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of liquid leakage detection and liquid chromatography, in particular to a liquid leakage detection alarm device. BACKGROUND

[0002] Many liquid leakage sensors used in the existing market liquid chromatography are detected by diodes, and the product cost is high. SUMMARY

[0003] The present application aims at the above problems, and provides a liquid leakage detection alarm device, which detects the liquid leakage through a thermistor, and outputs a normal working signal or an alarm signal through a circuit control single-chip microcomputer, so as to be low in cost and easy to realize.

[0004] A liquid leakage detection alarm device, comprising a thermistor R8, a thermistor R9, an operational amplifier U1A, an operational amplifier U1B, a triode Q1 and a single-chip microcomputer IC1.

[0005] The input direct current DC and the power supply voltage VCC3 are divided into two paths, one path is connected with the operational amplifier U1A through the thermistor R8 and a first voltage dividing circuit, and the other path is connected with the operational amplifier U1A through the thermistor R9 and a second voltage dividing circuit, the output of the operational amplifier U1A is connected to the operational amplifier U1B, the level of the output of the operational amplifier U1B is divided to obtain a conduction voltage for controlling whether the triode Q1 is turned on or not, and the single-chip microcomputer IC1 outputs a normal working signal or an alarm signal according to the conduction of the triode Q1.

[0006] Further, the resistance value of the thermistor changes according to the temperature change caused by contacting the leaked liquid.

[0007] Further, in the first voltage dividing circuit, the input direct current DC and the power supply voltage VCC3 pass through the thermistor R8 and are divided by the resistor R1, the capacitor C1 absorbs, the current flows clockwise, and the voltage at point A is obtained.

[0008] Further, in the second voltage dividing circuit, the input direct current DC and the power supply voltage VCC3 pass through the thermistor R9 and are divided by the resistor R2 and the adjustable resistor R3, the capacitor C2 absorbs, the current flows clockwise, and the voltage at point B is obtained.

[0009] Further, in the second voltage dividing circuit, the adjustable resistor R3 is used to adjust the voltage at point B, so that the voltage at point A is higher than the voltage at point B.

[0010] Further, the pins 5, 6 and 7 of the operational amplifier U1B form a follower.

[0011] Further, the pins 5 and 6 of the operational amplifier U1B are connected in parallel with the capacitor C3 for absorption.

[0012] Furthermore, when the voltage at point A is greater than the voltage at point B, pin 1 of the operational amplifier U1A outputs a low level, and pin 7 of the operational amplifier U1B also outputs a low level. No current flows through resistors R5 and R6, and capacitor C4 acts as an absorber. Transistor Q1 does not work, and the input port of microcontroller IC1 detects a high level on the third pin of transistor Q1, and microcontroller IC1 outputs a normal working signal.

[0013] Furthermore, when the resistance of thermistor R8 changes and the voltage at point B is greater than the voltage at point A, pin 1 of the operational amplifier U1A outputs a high level, and pin 7 of the operational amplifier U1B also outputs a high level. Pin 7 of the operational amplifier U1B outputs a high level, and when the appropriate turn-on voltage is obtained through voltage division by resistors R5 and R6, transistor Q1 is turned on. When the microcontroller IC1 detects that the third pin of the transistor Q1 is a low level, the internal program of the microcontroller IC1 processes the signal and outputs an alarm signal.

[0014] The beneficial effects achieved by the present invention are: replacing the original liquid leakage detection sensor with a thermistor, the principle is easy to understand and easy for operators to implement, the circuit structure is easy to implement, and can be widely promoted and used. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 2 is a structural diagram of a liquid leakage detection and alarm device in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings.

[0017] A liquid leakage detection and alarm device includes a thermistor R8, a thermistor R9, an operational amplifier U1A, an operational amplifier U1B, a transistor Q1 and a single-chip microcomputer IC1.

[0018] The input direct current DC and the supply voltage VCC3 are divided into two paths, one path is connected to the operational amplifier U1A through the thermistor R8 and the first voltage divider circuit, and the other path is connected to the operational amplifier U1A through the thermistor R9 and the second voltage divider circuit.

[0019] In the first voltage divider circuit, the input direct current DC and the supply voltage VCC3 pass through the thermistor R8 and are then divided by the resistor R1. The capacitor C1 absorbs the current, and the current flows clockwise to obtain the voltage at point A.

[0020] In the second voltage divider circuit, the input DC and supply voltage VCC3 pass through thermistor R9, then divide the voltage with resistor R2 and adjustable resistor R3. Capacitor C2 absorbs the current, and the current flows clockwise, resulting in the voltage at point B. In the second voltage divider circuit, adjustable resistor R3 adjusts the voltage at point B, making the voltage at point A higher than that at point B.

[0021] The output of op amp U1A is connected to op amp U1B. Pins 5, 6, and 7 of op amp U1B form a follower. Pins 5 and 6 of op amp U1B are connected in parallel with capacitor C3 for absorption.

[0022] The output level of the operational amplifier U1B is obtained through voltage division to obtain the conduction voltage for controlling whether the transistor Q1 is turned on. The microcontroller IC1 outputs a normal working signal or an alarm signal according to the conduction status of the transistor Q1.

[0023] When the voltage at point A is greater than the voltage at point B, pin 1 of operational amplifier U1A outputs a low level, and pin 7 of operational amplifier U1B also outputs a low level. No current flows through resistors R5 and R6, and capacitor C4 acts as an absorber. Transistor Q1 does not work, and the input port of microcontroller IC1 detects a high level on the third pin of transistor Q1, and microcontroller IC1 outputs a normal working signal.

[0024] When the resistance of thermistor R8 changes, the voltage at point B is greater than the voltage at point A, pin 1 of operational amplifier U1A outputs a high level, and pin 7 of operational amplifier U1B also outputs a high level. Pin 7 of operational amplifier U1B outputs a high level, and when the appropriate turn-on voltage is obtained through voltage division by resistors R5 and R6, transistor Q1 is turned on. When microcontroller IC1 detects that the third pin of transistor Q1 is at a low level, the internal program of microcontroller IC1 processes the signal and outputs an alarm signal.

[0025] The following is an example of the actual usage process:

[0026] With thermistor 5K, input voltage +12V example, if R9 thermistor itself temperature set 80 degrees resistance value is 0.8K (25 degrees for normal temperature 5K), R2, R3 resistance value set to 100 ohms and 100 ohms, R9 resistance value is 0.8K (80 degrees case) and R2, R3 voltage (2.4V) is obtained by B point voltage division, R8 set 100 degrees resistance value is 0.47K (25 degrees for normal temperature 5K), R1 is set to 150 ohms, R8 resistance value is 0.47K (25 degrees for normal temperature 5K), and R1 voltage (2.9V) is obtained by A point voltage division, A is greater than B, U1A the first foot output low level U1B the seventh foot also output low level, Q1 does not work, Q1 the third foot high level, single-chip microcomputer output normal signal, if R8 thermistor has liquid flow through itself temperature decreases to 2K (50 degrees), R8 (2K) and R1 (150R) voltage division obtains 0.8V (A point) voltage, at this time B point voltage (2.4V) is greater than A point voltage (0.8V), U1A the first foot output high level U1B the seventh foot also output high level, through R5 and R6 voltage division obtains the ideal triode base on voltage, Q1 works, Q1 the third foot low level, single-chip microcomputer output warning signal, through the display screen connected externally display warning.

[0027] The above description is only the preferred embodiment of the present application, the protection scope of the present application is not limited by the above embodiment, but any equivalent modification or change according to the disclosed content of the present application by the ordinary skill in the art, should be included in the protection scope recorded in the claim.

Claims

1. A liquid leak detection and alarm device, comprising a thermistor R8, a thermistor R9, an operational amplifier U1A, an operational amplifier U1B, a transistor Q1, and a single-chip microcomputer IC1, characterized in that: The input direct current DC and the supply voltage VCC3 are divided into two paths. One path is connected to the operational amplifier U1A through the thermistor R8 and the first voltage divider circuit, and the other path is connected to the operational amplifier U1A through the thermistor R9 and the second voltage divider circuit. The output of the operational amplifier U1A is connected to the operational amplifier U1B. The output level of the operational amplifier U1B is obtained through voltage division to obtain the conduction voltage for controlling whether the transistor Q1 is turned on. The microcontroller IC1 outputs a normal working signal or an alarm signal according to the conduction status of the transistor Q1. In the first voltage divider circuit, the input DC and the supply voltage VCC3 pass through the thermistor R8 and are then divided by the resistor R1. The capacitor C1 absorbs the current, and the current flows clockwise to obtain the voltage at point A. In the second voltage divider circuit, the input DC and the supply voltage VCC3 pass through the thermistor R9, and are then divided by the resistor R2 and the adjustable resistor R3. The capacitor C2 absorbs the current, and the current flows clockwise to obtain the voltage at point B. When the voltage at point A is greater than the voltage at point B, pin 1 of operational amplifier U1A outputs a low level, and pin 7 of operational amplifier U1B also outputs a low level. No current flows through resistors R5 and R6, and capacitor C4 acts as an absorber. Transistor Q1 does not work, and the input port of microcontroller IC1 detects a high level at pin 3 of transistor Q1, and microcontroller IC1 outputs a normal working signal. When the resistance of thermistor R8 changes, the voltage at point B is greater than the voltage at point A, pin 1 of operational amplifier U1A outputs a high level, and pin 7 of operational amplifier U1B also outputs a high level. Pin 7 of operational amplifier U1B outputs a high level, and when the appropriate turn-on voltage is obtained through voltage division by resistors R5 and R6, transistor Q1 is turned on. When microcontroller IC1 detects that the third pin of transistor Q1 is at a low level, the internal program of microcontroller IC1 processes the signal and outputs an alarm signal.

2. The liquid leakage detection and alarm device according to claim 1, characterized in that: The resistance of the thermistor changes according to the temperature change caused by contact with the leaking liquid.

3. The liquid leakage detection and alarm device according to claim 1, characterized in that: In the second voltage divider circuit, the voltage at point B is adjusted by the adjustable resistor R3 so that the voltage at point A is higher than the voltage at point B.

4. The liquid leakage detection and alarm device according to claim 1, characterized in that: Pins 5, 6, and 7 of operational amplifier U1B form a follower.

5. The liquid leakage detection and alarm device according to claim 1, characterized in that: Pins 5 and 6 of the operational amplifier U1B are connected in parallel with capacitor C3 for absorption.

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