Leakage protection circuit of liquid chromatograph
By employing a leakage protection circuit in the liquid chromatograph, utilizing a unidirectional thyristor and a resistor network to detect leakage signals, and controlling the AC circuit breaker through an MCU controller, the problem of insufficient reliability of leakage protection in the liquid chromatograph is solved, achieving low-cost and high-reliability safety protection.
Patent Information
- Application Number
- CN202511751373.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-26
- Publication Date
- 2026-01-23
AI Technical Summary
Existing leakage protection solutions for liquid chromatographs are either unreliable or too costly, and cannot effectively prevent leakage from AC/220V power supplies, posing a safety hazard.
A leakage current protection circuit is adopted, which uses a unidirectional thyristor and a resistor network to detect leakage current signals and controls the AC switch to open and close the circuit through an MCU controller to ensure that the power supply is cut off in time in case of leakage current. The self-locking characteristic of the thyristor is used to achieve hardware self-locking protection.
It achieves low-cost, high-reliability leakage protection, ensuring user safety under various uncertain conditions and preventing equipment damage and personal injury.
Smart Images
Figure CN121395207A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a liquid chromatograph, in particular to a leakage protection circuit of a liquid chromatograph. BACKGROUND
[0002] In the medical field, the liquid chromatograph is usually powered by AC / 220V power supply. However, the AC / 220V power supply may leak after long-term use of the device or due to some uncertain factors. Such leakage not only may damage the device, but more seriously, may pose a threat to the personal safety of the operator. Therefore, it is urgent to provide a reliable leakage protection mechanism in the liquid chromatograph to cut off the power supply in time when leakage occurs, avoid dangerous accidents, and protect the personal safety of the user. The existing protection scheme may have problems such as insufficient reliability or high cost, and it is necessary to propose a more effective and practical leakage protection circuit. SUMMARY
[0003] The purpose of the present application is to provide a leakage protection circuit of a liquid chromatograph to avoid the occurrence of accidental leakage of AC / 220V power supply.
[0004] The technical scheme of the present application is: A leakage protection circuit of a liquid chromatograph, the leakage protection circuit collects a leakage signal of the liquid chromatograph and sends it to an MCU controller of the liquid chromatograph, the MCU controller is connected to control the on-off of an AC switch of the liquid chromatograph, and the AC switch is used to turn on the AC / 220V power supply to supply power to the liquid chromatograph.
[0005] Preferably, the leakage protection circuit comprises a unidirectional thyristor D1 and resistors R1-R4; the anode of the unidirectional thyristor D1 is connected to a 3.3V voltage power supply end through a resistor R1, the cathode is grounded through a resistor R2, resistors R3 and R4 are connected in series between the shell of the liquid chromatograph and the ground, the connection point between resistors R3 and R4 is connected to the trigger stage of the unidirectional thyristor D1, and the cathode of the unidirectional thyristor D1 is connected to the identification port of the MCU controller.
[0006] Preferably, the cathode of the unidirectional thyristor D1 is also grounded through a capacitor C1.
[0007] Preferably, the AC switch is started by a button, the MCU controller first detects the leakage signal, when there is no leakage signal, the devices of the liquid chromatograph are started in sequence and begin to work; when the MCU controller receives the leakage signal of the leakage protection circuit, the AC switch is immediately disconnected and the devices of the liquid chromatograph are stopped running.
[0008] Preferably, the devices of the liquid chromatograph include a solution storage tank, a high-pressure liquid pump, a sample injector, a chromatographic column, a detector, and a data processing system which are connected in sequence. If any device in the liquid chromatograph experiences a leakage current during operation, the leakage current signal is sent to the leakage protection circuit through the casing. The leakage protection circuit then sends the leakage current signal to the MCU controller, which immediately disconnects the AC power and stops all devices from operating.
[0009] The advantages of this invention are: The leakage protection circuit of the liquid chromatograph of this invention adopts a low-cost solution, utilizing the self-locking characteristic of a thyristor to maintain current, ensuring reliable hardware self-locking even in the event of software self-locking failure. The hardware protection offers a significantly higher safety factor than software protection, ensuring the user's safety under various uncertain leakage conditions. Attached Figure Description
[0010] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the leakage protection operation logic of the leakage protection circuit of a liquid chromatograph. Figure 2 This is a schematic diagram of a leakage current protection circuit. Detailed Implementation
[0011] like Figure 1 As shown, the leakage protection circuit of the liquid chromatograph of the present invention includes the following components connected in sequence: a solution storage tank A, a high-pressure pump B, an injector C, a chromatographic column D, a detector E, and a data processing system F. The leakage protection circuit H collects the leakage signal of the liquid chromatograph and sends it to the MCU controller G of the liquid chromatograph. The MCU controller G controls the on / off state of the AC switch I of the liquid chromatograph, which is used to connect the AC / 220V power supply to the liquid chromatograph.
[0012] When AC circuit breaker I and AC / 220V power are connected, and the operator presses the start button: 1. First, the MCU controller G detects the leakage signal. If there is no leakage signal, it sequentially starts six devices: solution storage tank A, high-pressure infusion pump B, injector C, chromatographic column D, detector E, and data processing system F, and begins operation.
[0013] 2. When the MCU controller G receives the leakage current signal from the leakage current protection circuit H, it immediately disconnects the AC power switch I and stops the operation of all devices such as A, B, C, D, E, and F.
[0014] 3. When the equipment is running, if any one of the devices A, B, C, D, E, and F experiences a leakage current, the leakage current signal will be sent to the leakage protection circuit H through the casing. The leakage protection circuit H will then send the leakage current signal to the MCU controller G. The MCU controller G will immediately disconnect the AC power switch and stop the operation of the six devices A, B, C, D, E, and F.
[0015] 4, AC switch I initial state is off, the device is turned on to connect AC / 220V power supply always need MCU controller G, MCU controller G control always need to detect the leakage signal before the execution of open and close action.
[0016] As shown in Figure 2 the leakage protection circuit H includes unidirectional thyristor D1, resistors R1-R4 and capacitor C1; the anode of the unidirectional thyristor D1 is connected to the 3.3V voltage supply end through resistor R1, the cathode is connected to ground through parallel resistor R2 and capacitor C1, resistor R3, R4 are connected in series between the housing of the liquid chromatograph and the ground, the connection point between resistor R3, R4, the trigger stage of unidirectional thyristor D1, the cathode of unidirectional thyristor D1 is connected to the identification port of MCU controller.
[0017] The unidirectional thyristor D1 uses BT169D, under normal circumstances, the anode 3.3V voltage of the thyristor will not be conducted to the cathode, when the thyristor trigger stage receives the signal, the PN junction of the anode and the cathode is conducted, the 3.3V of the anode is conducted to the cathode, the cathode and the MCU controller G identification foot are connected, at this time, the MCU controller G will read the leakage signal, and initiate the closing AC switch I signal to close the switch.
[0018] The embodiment utilizes the self-locking characteristic of thyristor, when the anode and the cathode of the thyristor are conducted, the trigger stage is conducted to the ground current greater than 5mA, the anode and the cathode of the thyristor will be in self-locking conduction, always locked in the conduction state, only by turning on and off the switch, the thyristor is reset to cancel the self-locking. This scheme has low cost, and the hardware self-locking reliability is higher than that of software self-locking.
[0019] The above embodiments are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and it cannot limit the protection scope of the present application. Any modification made according to the spirit and essence of the main technical solution of the present application should be covered within the protection scope of the present application.
Claims
1. A leakage protection circuit for a liquid chromatograph, characterized in that, The leakage protection circuit collects the leakage signal of the liquid chromatograph and sends it to the MCU controller of the liquid chromatograph. The MCU controller is connected to control the AC power switch of the liquid chromatograph, which is used to connect the AC / 220V power supply to the liquid chromatograph.
2. The leakage protection circuit for a liquid chromatograph according to claim 1, characterized in that, The leakage protection circuit includes a unidirectional thyristor D1 and resistors R1-R4. The anode of the unidirectional thyristor D1 is connected to the 3.3V power supply terminal through resistor R1, and the cathode is grounded through resistor R2. Resistors R3 and R4 are connected in series between the casing of the liquid chromatograph and ground. The connection point between resistors R3 and R4 is connected to the trigger stage of the unidirectional thyristor D1, and the cathode of the unidirectional thyristor D1 is connected to the identification port of the MCU controller.
3. The leakage protection circuit for a liquid chromatograph according to claim 2, characterized in that, The cathode of the unidirectional thyristor D1 is also grounded through capacitor C1.
4. The leakage protection circuit for a liquid chromatograph according to claim 2, characterized in that, The AC switch is activated by a button. The MCU controller first detects the leakage signal. If there is no leakage signal, it starts each device of the liquid chromatograph in sequence and begins to work. When the MCU controller receives a leakage signal from the leakage protection circuit, it immediately disconnects the AC switch and stops the operation of each device of the liquid chromatograph.
5. The leakage protection circuit for a liquid chromatograph according to claim 4, characterized in that, The components of the liquid chromatograph include, in sequence, a solution storage tank, a high-pressure pump, an injector, a chromatographic column, a detector, and a data processing system. If any device in the liquid chromatograph experiences a leakage current during operation, the leakage current signal is sent to the leakage protection circuit through the casing. The leakage protection circuit then sends the leakage current signal to the MCU controller, which immediately disconnects the AC power and stops all devices from operating.