阅读说明：本技术 一种用于液相色谱仪的漏液双重监控报警保护系统及方法 (Liquid leakage double-monitoring alarm protection system and method for liquid chromatograph ) 是由 林雪志 蒋婷婷 周小靖 于 2021-03-09 设计创作，主要内容包括：本发明涉及一种用于液相色谱仪的漏液双重监控报警保护系统,包括柱温箱模块的柱腔以及输液泵模块、自动进样器模块、柱温箱模块、检测器模块的机箱。所述柱温箱的柱腔中设置有有机气体泄漏传感器；模块的机箱内部配置有通风系统,并设置有用于安装电路控制部件的第一安装区、用于安装流路部件的第二安装区,所述机箱外部依次设置有漏液收集器和液体接触式漏液传感器,所述漏液收集器设置于第二安装区的下方,所述第一安装区和第二安装区的分隔处还设置有气体传感器。本发明提供的技术方案使用有机气体泄漏传感器和液体接触式漏液传感器的双重实时监控的方式,以确保漏液后及时提示并处置,并确保仪器安全运行。(The invention relates to a leakage double monitoring alarm protection system for a liquid chromatograph, which comprises a column cavity of a column temperature box module, an infusion pump module, an automatic sample injector module, a column temperature box module and a case of a detector module. An organic gas leakage sensor is arranged in a column cavity of the column incubator; the module comprises a module, a circuit control component, a leakage collector, a liquid contact type leakage sensor, a ventilation system, a first mounting area and a second mounting area, wherein the ventilation system is arranged in a case of the module, the first mounting area is used for mounting the circuit control component, the second mounting area is used for mounting the flow path component, the leakage collector and the liquid contact type leakage sensor are sequentially arranged outside the case, the leakage collector is arranged below the second mounting area, and a gas sensor is further arranged at the separation position of the first mounting area and the second mounting area. The technical scheme provided by the invention adopts a double real-time monitoring mode of the organic gas leakage sensor and the liquid contact type leakage sensor to ensure prompt and treatment in time after leakage and ensure safe operation of the instrument.)

1. A leakage double monitoring alarm protection system for a liquid chromatograph is characterized by structurally comprising a column cavity of a column temperature box module, an infusion pump module, an automatic sample injector module, a column temperature box module and a chassis of a detector module; at least one organic gas leakage sensor is arranged in a column cavity of the column incubator; the device is characterized in that a ventilation system is arranged in a case of at least one of the infusion pump module, the automatic sample injector module, the column temperature box module and the detector module, a first mounting area for mounting a circuit control part and a second mounting area for mounting a flow path part are arranged inside the case, a leakage collector and a liquid contact type leakage sensor are sequentially arranged outside the case, the leakage collector is arranged below the second mounting area, and at least one organic gas leakage sensor is arranged at the separation position of the first mounting area and the second mounting area

And in the dual monitoring, the leaked organic vapor and organic liquid are respectively subjected to dual detection monitoring by an organic gas leakage sensor and a liquid contact type liquid leakage sensor.

2. The double monitoring and alarm system for liquid leakage of liquid chromatograph of claim 1, wherein the column cavity of said column oven is a temperature controlled area for installing chromatographic column; the ventilation system of the case consists of an air inlet, an air outlet and a power fan and is used for replacing air in the case.

3. The double monitoring and alarm system for liquid leakage of liquid chromatograph of claim 1, wherein said circuit control components comprise a power supply, a circuit board, a component controller; the flow path component comprises a mixer, a damper, a pump, a tee joint, a pipeline and a pipeline joint, and the pipeline joint are arranged outside the case; the leakage collector is made of organic solvent resistant materials, and the upper plane of the leakage collector is provided with a fluid guide slope.

4. The dual monitoring and alarming system for liquid leakage of liquid chromatograph of claim 1, wherein said liquid contact type leakage sensor uses thermistor as sensing element, and adopts dual-path thermistor reference detection mode, and a bridge detection voltage amplifying circuit with temperature compensation is arranged in the supporting circuit of said liquid contact type leakage sensor, and said bridge detection voltage amplifying circuit includes operational amplifier and AD converter.

5. The dual monitoring and alarm system for liquid chromatograph leakage of claim 1, wherein said organic gas leakage sensor comprises a semiconductor type, a solid electrolyte type, an electrochemical type, said semiconductor type using a sensing element whose conductivity is sensitive to organic gases.

6. A double-monitoring alarm protection method for leakage of a liquid chromatograph, based on the double-monitoring alarm protection system for leakage of a liquid chromatograph described in the above claims 1-5, comprising a system CPU, each working module CPU, a workstation, a liquid contact leakage sensor, an organic gas leakage sensor, a cabinet ventilation system, etc., and cooperatively completing real-time leakage monitoring and protection of the liquid chromatograph according to a certain control mode, characterized by comprising the following steps:

s1: after the system is started up, a user sets a liquid leakage alarm threshold value, the workstation communicates with the CPU, and a recommended gas alarm threshold value is calculated;

s2: selecting a recommended gas alarm threshold or a user-defined gas alarm threshold as an organic gas alarm threshold of the current system;

s3: receiving current values of the organic gas sensor and the liquid contact type liquid leakage sensor, correspondingly comparing the current values with an organic gas alarm threshold value and a liquid leakage alarm threshold value of a current system, judging that the liquid leakage state exists when any one current value of the organic gas sensor and the liquid contact type liquid leakage sensor exceeds the corresponding threshold value, and otherwise, judging that the liquid leakage state does not exist;

s4: the workstation issues the current state information to each working module, and the CPU arranged in the working module combines the current liquid leakage alarm state information according to respective characteristics to complete internal processing: if the current state is a leakage state, starting a leakage alarm prompt and protection processing mechanism in each module; and if the current state is a non-leakage state, the alarm prompt is released, and the other modules are restored to the target state set by the user method except that the infusion pump module maintains the current state.

7. The double monitoring and alarming method for liquid leakage of liquid chromatograph of claim 6, wherein the process of obtaining the gas alarm threshold in step S1 is:

s1.1: the CPU receives the method information of the workstation, extracts and identifies the organic solvent information;

s1.2: the CPU calls a built-in common organic solvent physical property table to extract the explosion limit of the currently used organic solvent;

s1.3: and calling a built-in common organic solvent gas concentration-response value relation curve library by the CPU, and circularly comparing and calculating by adopting an interpolation method to obtain a system recommended gas alarm threshold value corresponding to the current organic solvent explosion lower limit.

8. The double monitoring and alarming method for liquid leakage of liquid chromatograph of claim 6, wherein the specific process of step S2 is as follows:

s2.1: prompting a user by the workstation whether to define a gas alarm threshold value by the user, wherein if the gas alarm threshold value is defined by the user, and if the gas alarm threshold value is not defined as the organic gas alarm threshold value of the current system;

s2.2: and judging whether the self-defined gas alarm threshold is lower than the recommended gas alarm threshold by the workstation, if so, defining the self-defined gas alarm threshold as the organic gas alarm threshold of the current system, otherwise, prompting the user to reset the self-defined gas alarm threshold.

9. The double monitoring alarm method for liquid leakage of liquid chromatograph of claim 6, wherein the operation modules in step S4 include an auto-injector, a column oven and a detector; the pump module is an infusion pump, and the infusion pump stops infusion immediately when liquid leakage is confirmed and waits for follow-up examination.

10. The double monitoring and alarming method for liquid leakage of liquid chromatograph of claim 6, wherein the process of S1-S4 is repeatedly executed at intervals of Δ t, and the judgment logic of each of said operation module and pump module adopts double judgment logic, and after the CPU issues a command to shut down the function unit or stop the module from operating, the workstation automatically executes the judgment logic once again to complete the process.

Technical Field

The invention belongs to the field of liquid chromatography detection, and particularly relates to a leakage double-monitoring alarm protection system and method for a liquid chromatograph.

Background

The liquid chromatograph uses a liquid (usually containing an organic solvent) as a mobile phase. During use, there is a possibility that leakage may occur even when the operation of the pipe joint, the flow path member, and the like is irregular or aged. Liquid leakage may occur inside the column cavity of the column oven and outside parts of each module case, such as various pipe joints and the like; it is also possible that flow path components such as buffers, mixers, flow cells, etc. occur. The pipeline joint and the flow path component are distributed in the column cavity of the column incubator or the inside and the outside of each module case in different degrees according to different instrument structures and layouts. Generally, the existing safety measures for liquid leakage are that a drainage device is installed below a position where liquid leakage is likely to occur, leaked liquid is led out to the outside of a case and collected to a contact type liquid leakage sensor position, and a liquid leakage alarm protection mechanism is triggered. The liquid leakage alarm protection mechanism generally cuts off the liquid delivery of a flow path, all heating outputs of a system and the power supply inside a liquid leakage module.

Generally, in the prior art, a thermistor is commonly used as a liquid leakage detection element, when liquid contacts the surface of the thermistor, temperature difference exists between the liquid and the environment, and partial heat is taken away by volatilization of the liquid, so that the temperature of the thermistor changes, the resistance value changes, and finally, an alarm is realized after the temperature is processed by a circuit system. The alarm principle is not difficult to obtain, and the leaked liquid must be in direct contact with the leakage sensor to trigger an alarm protection mechanism. The conventional leakage sensor is generally arranged at the centralized layout position of the external pipeline joint of the case, so that the pipeline or the component outside the case easily generates leakage to cause a leakage alarm protection mechanism, and even if trace leakage is not converged at the sensor, the trace leakage sensor is easily discovered by an operator to take measures in time. In addition, the potential safety hazard of leakage outside the case is relatively low.

The current liquid leakage alarm technology (direct contact triggering alarm) has obvious defects and major potential safety hazards as follows: firstly, once the liquid that leaks in the quick-witted case of each module can not converge to weeping sensor department because of various reasons, can not initiate the alarm protection mechanism, general operating personnel just also be difficult for discovering the instrument weeping and take corresponding measure. And secondly, liquid leakage is generated on a joint or a component in a column cavity of the column temperature box, and the liquid is easy to volatilize before collection because the column cavity is a temperature control area and the using temperature is higher than the room temperature. The existing leakage alarm technology cannot detect and alarm for protection under the two conditions. The common liquid chromatograph usually uses organic solvent or liquid containing organic solvent as mobile phase, that is, the liquid leaked from each part generally contains organic solvent, such as common mobile phase methanol, acetonitrile, etc., because the common organic solvent has low boiling point and is very volatile, and its explosion limit is wide, and the explosion limit is very low, taking methanol as example, its explosion range is 5.5% -44%, the volume of each module cabinet is calculated according to 40L, 3ml of methanol volatilizes to reach its explosion limit, while the volume of column cavity of general column oven is only 0.5-2L, and the extremely trace (about 0.1 ml) of methanol volatilizes to reach its explosion limit. If the circuit components or heating components in the case or the column chamber generate sparks, explosion accidents are caused, and the safety of life and property is threatened.

A column oven for a liquid chromatograph and a liquid chromatograph including a column temperature adjusting section, a separation column, a leak detection section, and a leak temperature adjusting section are disclosed in patent publication No. CN 107589210A; the separation column is positioned in the column temperature adjusting part, and the column temperature adjusting part is used for adjusting the temperature of the separation column; the leakage detection part comprises a first temperature sensor and a second temperature sensor and is used for detecting the existence of leakage formed after the liquid flowing through the separation column leaks out of the column temperature regulation part; the leakage temperature adjusting part is used for reducing the temperature of leakage flowing through the leakage temperature adjusting part, so that the difference value between the second temperature and the ambient temperature is smaller than a preset threshold value after the heat transfer between the leakage and the second temperature sensor occurs. The invention can effectively improve the leakage detection efficiency and accuracy of the liquid chromatograph, improve the fault removal efficiency of the liquid chromatograph and reduce the waste of the mobile phase solvent.

Patent publication No. CN209264650U discloses a liquid chromatograph column temperature case that can monitor small weeping, including box, case lid, chromatographic column and two connecting pieces, the chromatographic column is located in the box and both ends are connected with two connecting pieces respectively, is equipped with supporting shoe and two removal portions in the box, and the supporting shoe is located box bottom surface middle part chromatographic column below and is contacted with the chromatographic column. The moving part comprises a sliding block and a temperature sensor, the temperature sensor is arranged above the sliding block, the temperature sensor is in contact with the connecting parts of the two ends of the chromatographic column and the connecting piece, two sliding grooves are formed in the bottom surface of the box body, and the sliding block is contained in the sliding grooves and can slide in the sliding grooves. The box body is externally provided with a control box, a PCB is arranged in the control box, the PCB is welded with a main control module, a power supply module, a processing module and an alarm module, and the temperature sensor is respectively connected with the power supply module and the main control module. The power module comprises a constant current source circuit, and the processing module comprises a temperature measuring circuit and a processing circuit. The utility model discloses can monitor the small weeping condition of chromatographic column junction during the application.

In the above patents, the liquid direct contact type leakage sensor is adopted, and only the external temperature change or the leakage position change is optimized correspondingly, and the condition of volatilization of the leaked liquid cannot be detected, so that the influence on analysis and potential safety hazard caused by the existence of organic solvent vapor in a case or a cavity containing a circuit component or a heating component cannot be avoided. In addition, the aspects of the patent judgment mechanisms are single judgment modes, the judgment accuracy and stability are poor, and the false alarm triggering caused by external environment change cannot be avoided.

Disclosure of Invention

In order to solve the problems, the invention provides a leakage double monitoring alarm protection system and a leakage double monitoring alarm protection method for a liquid chromatograph, wherein organic gas leakage sensors are used in a column cavity of a column temperature box and the inner part of a case of each module, and a double real-time monitoring mode of a liquid contact type leakage sensor is used at a drainage liquid collection position outside the case of each module so as to ensure prompt and treatment in time after leakage and ensure safe operation of an instrument.

The technical scheme of the invention is as follows:

a leakage double monitoring alarm system for a liquid chromatograph structurally comprises a column cavity of a column temperature box module, an infusion pump module, an automatic sample injector module, a column temperature box module and a chassis of a detector module; at least one organic gas leakage sensor is arranged in a column cavity of the column incubator; the device comprises an infusion pump module, an automatic sample injector module, a column temperature box module and a detector module, wherein a ventilation system is arranged in a case of at least one of the infusion pump module, the automatic sample injector module, the column temperature box module and the detector module, a first mounting area for mounting a circuit control part and a second mounting area for mounting a flow path part are arranged inside the case, a leakage collector and a liquid contact type leakage sensor are sequentially arranged outside the case, the leakage collector is arranged below the second mounting area, and the separation part of the first mounting area and the second mounting area is also provided with at least one organic gas leakage sensor.

Preferably, the column cavity of the column oven is a temperature control area for installing the chromatographic column; the ventilation system of the case consists of an air inlet, an air outlet and a power fan, and air in the case can be quickly replaced after the ventilation system is opened.

Preferably, the circuit control component comprises a power supply, a heating element, a circuit board, a component controller; the flow path component comprises a mixer, a damper, a pump, a tee joint, a pipeline and a pipeline joint, and the pipeline joint are arranged outside the case; the leakage collector is made of organic solvent resistant materials, and the upper plane of the leakage collector is provided with a fluid guide slope.

Preferably, the liquid contact type liquid leakage sensor adopts a thermistor as a sensing element, adopts a two-way thermistor reference detection mode, and is provided with a bridge circuit detection voltage amplification circuit with temperature compensation in a matching circuit, wherein the bridge circuit detection voltage amplification circuit comprises an operational amplifier and an AD converter.

Preferably, the organic gas leakage sensor includes a semiconductor type, a solid electrolyte type, and an electrochemical type, and the semiconductor type uses a sensor element whose conductivity is sensitive to an organic gas.

The invention also provides a leakage double monitoring and alarming method for the liquid chromatograph, which is characterized by comprising the following steps:

s1: a user sets a liquid leakage alarm threshold value, the workstation communicates with the CPU, and a recommended gas alarm threshold value is calculated;

s2: selecting a recommended gas alarm threshold or a user-defined gas alarm threshold as an organic gas alarm threshold of the current system;

s3: receiving current values of the organic gas sensor and the liquid contact type liquid leakage sensor, correspondingly comparing the current values with an organic gas alarm threshold value and a liquid leakage alarm threshold value of a current system, judging that the liquid leakage state exists when any one current value of the organic gas sensor and the liquid contact type liquid leakage sensor exceeds the corresponding threshold value, and otherwise, judging that the liquid leakage state does not exist;

s4: the workstation issues the current state information to each working module, and the CPU arranged in the working module combines the current liquid leakage alarm state information according to respective characteristics to complete internal processing: if the current state is a leakage state, starting a leakage alarm prompt and protection processing mechanism in each module; and if the current state is a non-leakage state, the alarm prompt is released, and the other modules are restored to the target state set by the user method except that the infusion pump module maintains the current state.

Preferably, the acquiring process of the gas alarm threshold in step S1 is as follows:

s1.1: the CPU receives the method information of the workstation, extracts and identifies the organic solvent information;

s1.2: the CPU calls a built-in common organic solvent physical property table to extract the explosion limit of the currently used organic solvent;

s1.3: and calling a built-in common organic solvent gas concentration-response value relation curve library by the CPU, and circularly comparing and calculating by adopting an interpolation method to obtain a system recommended gas alarm threshold value corresponding to the current organic solvent explosion lower limit.

Preferably, the specific process of step S2 is as follows:

s2.1: prompting a user by the workstation whether to define a gas alarm threshold value by the user, wherein if the gas alarm threshold value is defined by the user, and if the gas alarm threshold value is not defined as the organic gas alarm threshold value of the current system;

s2.2: and judging whether the self-defined gas alarm threshold is lower than the recommended gas alarm threshold by the workstation, if so, defining the self-defined gas alarm threshold as the organic gas alarm threshold of the current system, otherwise, prompting the user to reset the self-defined gas alarm threshold.

Preferably, the operation module in step S4 includes an auto sampler, a column oven, and a detector; the pump module adopts an infusion pump, and the infusion pump stops infusion immediately when liquid leakage is confirmed and waits for follow-up examination.

Preferably, the process of S1-S4 is repeatedly executed at intervals of Δ t, and the judgment logics of the operating module and the pump module adopt dual judgment logics, and after the CPU issues a command to close the functional part or stop the module from operating, the workstation automatically executes the judgment logics once again to complete the processing.

The invention has the technical effects that:

the invention adopts a high-sensitivity organic gas sensor in the cavity of the column oven; in addition, a conventional liquid contact type leakage sensor is used at a drainage liquid collection position outside a case of each module (comprising an infusion pump, an automatic sample injector, a column incubator, a detector and the like), and a dual real-time monitoring mode of an organic gas leakage sensor is used inside the case of each module, so that prompt and treatment can be timely performed after leakage is ensured, and safe operation of an instrument can be ensured.

The technical scheme provided by the invention is structurally characterized in that firstly, a high-sensitivity organic gas leakage sensor is arranged in a column cavity of a column temperature box module; secondly, aiming at the case of each module, a ventilation system capable of quickly replacing air in the case is arranged, the flow path components and the circuit components are spatially isolated in the layout, liquid leakage drainage grooves are arranged below all the flow path components, and a liquid contact type liquid leakage sensor is arranged at a liquid collection position. Therefore, even if liquid leakage occurs in the components, the liquid cannot directly contact any circuit component, and the liquid can be detected after collection to trigger an alarm protection mechanism, so that the hidden danger of safety problems caused by contact of the liquid and a circuit system is avoided. Furthermore, high-sensitivity organic gas sensors are arranged in the column oven cavity and the machine boxes of all the modules, alarm limits are set on a control program, the high-sensitivity organic gas sensors are provided with amplification detection circuits, organic gas which is obviously smaller than the lower explosion limit of common organic solvents can trigger induction, when the concentration of the organic gas in the column oven cavity and the machine boxes of all the modules exceeds the alarm limits, a system alarms, all the modules immediately start a machine box ventilation system, organic gas is quickly removed and replaced, and a liquid leakage protection mechanism is started according to the characteristics of all the modules. After the alarm state is released, the other modules are restored to the target state set by the user method except that the infusion pump module maintains the current state.

The technical scheme provided by the invention adopts different alarm triggering mechanisms in control according to different characteristics of the liquid leakage sensor and the gas leakage sensor. The liquid contact type leakage sensor adopts a double-path thermistor reference detection mode, and uses a bridge circuit amplifying circuit with temperature compensation in control, so that false alarm caused by environmental temperature fluctuation can be completely avoided. The gas leakage sensor alarm mechanism adopts a control mode that common organic solvent parameters are arranged in a CPU, and the CPU accurately calculates and reserves a safe proportion according to user setting information. And two kinds of weeping sensors adopt the mode of two-way real-time cruise monitoring, carry out the comprehensive control in space and time to instrument outside and inside the column incubator, avoid influencing the analysis because of the weeping does not perceive, avoided the emergence of incident.

Drawings

Fig. 1 is a schematic structural diagram of the apparatus provided by the present invention.

FIG. 2 is a schematic circuit diagram of a bridge circuit detection voltage amplifying circuit in the leakage sensor of the present invention.

Fig. 3 is a flow chart of a method provided by the present invention.

FIG. 4 is a flow chart of the system CPU of the present invention for obtaining a recommended gas alarm threshold.

FIG. 5 is a CPU control logic diagram for an infusion pump.

FIG. 6 is a diagram of the autosampler CPU control logic.

FIG. 7 is a control logic diagram of the column oven CPU.

FIG. 8 is a detector CPU control logic diagram.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, a double monitoring and alarming system for liquid leakage of a liquid chromatograph comprises a case of all modules, wherein the inside of the case is divided into a first mounting area for mounting a circuit control component and a second mounting area for mounting a flow path component in space, the second mounting area is close to the front part of the system, extends to the outside of the case and is close to the bottom of the case, and is provided with an integrated leakage collector and a liquid contact leakage sensor, all the flow path components and pipeline joints are mounted on the upper part of the leakage collector, and a high-sensitivity organic gas sensor is further arranged at the separation part of the first mounting area and the second mounting area. In addition, a high-sensitivity organic gas sensor is arranged in a column cavity of the column incubator module.

As an embodiment of the present invention, structurally, the present invention includes a plurality of modules, specifically, an autosampler, a column oven, a detector, and an infusion pump, each module is disposed in a separate housing, an organic gas sensor is installed in each housing, and in addition, a highly sensitive organic gas sensor is also installed in a column cavity of the column oven module. The conventional liquid contact type leakage sensor is used at the drainage liquid collection position outside the machine cases of all the modules, and the double real-time monitoring mode of the organic gas leakage sensor is used inside the machine cases of all the modules, so that prompt and treatment are timely performed after liquid leakage is ensured, and the safe operation of the instrument is ensured.

And because the risk of leakage outside the case is lower than that inside the case, the pipeline joint and the flow path component are arranged outside the case as much as possible, and the flow path component which is required to be arranged inside the case partially because of functions or other factors is arranged in the flow path component mounting area inside the case.

The leakage collector is made of organic solvent resistant material, the upper plane is provided with a fluid guide slope part, and the lowest point collection part is connected to the waste liquid collector. After the liquid drops to the leakage collector, the liquid flows along the guide inclined plane and finally is collected to the liquid contact type leakage sensor outside the case.

The circuit control component comprises a power supply, a heating element, a circuit board and a component controller.

The flow path component comprises a mixer, a damper, a pump, a tee joint, a pipeline and a pipeline joint, and the pipeline joint are arranged outside the case.

If leakage occurs at a pipeline joint or a component outside the case, the leakage liquid is collected to the liquid contact type leakage sensor through a drainage device such as a leakage groove.

In the embodiment, the flow path parts and the circuit parts are spatially isolated, and the leakage grooves are arranged below all the flow path parts, so that even if the parts generate leakage, liquid cannot directly contact any circuit part, and the potential safety problem caused by the contact of the liquid and a circuit system is avoided.

As shown in fig. 2, a bridge circuit detection voltage amplifying circuit with temperature compensation is arranged in the liquid contact type leakage sensor, and the bridge circuit detection voltage amplifying circuit comprises an operational amplifier, an AD converter and a thermistor. The liquid leakage sensor adopts the working principle that a bridge circuit with temperature compensation is adopted to detect a voltage amplifying circuit, when fluid flows through a thermistor, the temperature of the fluid changes, resistance value change of the resistor is caused, voltage difference is generated on the bridge circuit, the voltage difference is amplified by the amplifying circuit and is subjected to temperature compensation correction, and then the current value is output. The current value is output to the workstation through the module CPU, and whether to give an alarm or not is judged after the comparison between the workstation and the set value of the user.

In the embodiment, the high-sensitivity organic gas sensors are arranged in the column oven cavity and the machine cases of all the modules, the alarm limit is set on the control program, and the high-sensitivity organic gas sensors are provided with the amplification detection circuit, so that the organic gas which is obviously smaller than the explosion lower limit of the common organic solvent can trigger induction. When the concentration of the organic gas in the cavity of the column incubator or the case exceeds the alarm limit, the system alarms, and each module starts a liquid leakage protection mechanism.

As shown in fig. 3, the present invention further provides a double monitoring and alarming method for liquid leakage of a liquid chromatograph, which adopts a two-way real-time cruise monitoring mode according to the characteristics of two liquid leakage sensors to comprehensively monitor the space and time of the outside of the instrument, the inside of each module case and the column cavity of the column oven, thereby avoiding the invalidation of analysis data and the occurrence of safety accidents caused by the undetected liquid leakage, and comprises the following steps:

s1: a user sets a liquid leakage alarm threshold value, the workstation communicates with the CPU, and a recommended gas alarm threshold value is calculated;

s2: selecting a recommended gas alarm threshold or a user-defined gas alarm threshold as an organic gas alarm threshold of the current system;

s3: receiving current values of the organic gas sensor and the liquid contact type liquid leakage sensor, correspondingly comparing the current values with an organic gas alarm threshold value and a liquid leakage alarm threshold value of a current system, judging that the liquid leakage state exists when any one current value of the organic gas sensor and the liquid contact type liquid leakage sensor exceeds the corresponding threshold value, and otherwise, judging that the liquid leakage state does not exist;

s4: the workstation issues the current state information to each working module, and the CPU arranged in the working module combines the current liquid leakage alarm state information according to respective characteristics to complete internal processing: if the current state is a leakage state, starting a leakage alarm prompt and protection processing mechanism in each module; and if the current state is a non-leakage state, the alarm prompt is released, and the other modules are restored to the target state set by the user method except that the infusion pump module maintains the current state.

As an embodiment of the present invention, as shown in fig. 4, the process of acquiring the gas alarm threshold in step S1 is as follows:

s1.1: the CPU receives the method information of the workstation, extracts and identifies the organic solvent information;

s1.2: the CPU calls a built-in common organic solvent physical property table to extract the explosion limit of the currently used organic solvent;

s1.3: and calling a built-in common organic solvent gas concentration-response value relation curve library by the CPU, and circularly comparing and calculating by adopting an interpolation method to obtain a system recommended gas alarm threshold value corresponding to the current organic solvent explosion lower limit.

For gas alarm, a sensor with higher sensitivity to organic solvents commonly used in liquid chromatography is selected first. Generally, a sensor element sensitive to organic gases with conductivity, such as a tin dioxide (SnO 2) sensor, can be selected, which has a lower conductivity in clean air, and a significantly increased conductivity when organic gas components are present, and which increases with increasing concentration of organic components.

In actual control, a system CPU firstly receives mobile phase information issued by a workstation to obtain the information of the organic solvent in current system operation. Then, a common organic solvent physical property table built in the program is called, and the explosion limit information of the current organic solvent is extracted. The present invention program is currently built in including but not limited to the following organic solvent physicochemical information: methanol, acetonitrile, n-hexane, cyclohexane, tetrahydrofuran, isopropanol, n-propanol, and the like. And then calling a corresponding curve in a built-in relation curve library of response values of the common organic solvent and the gas concentration of the common organic solvent by the CPU, and circularly comparing and calculating by adopting an interpolation method to obtain a system recommended gas alarm threshold value corresponding to the current organic solvent explosion lower limit. The present invention is based on experimental data and the currently built-in curves include, but are not limited to, the following organic solvents: methanol, acetonitrile, n-hexane, cyclohexane, tetrahydrofuran, isopropanol, n-propanol, and the like.

As an embodiment of the present invention, as shown in fig. 3, the specific process of step S2 is:

s2.1: prompting a user by the workstation whether to define a gas alarm threshold value by the user, wherein if the gas alarm threshold value is defined by the user, and if the gas alarm threshold value is not defined as the organic gas alarm threshold value of the current system;

s2.2: and judging whether the self-defined gas alarm threshold is lower than the recommended gas alarm threshold or not by the workstation, if so, defining the self-defined gas alarm threshold as the organic gas alarm threshold of the current system, otherwise, prompting a user that the self-defined threshold is not more than a system calculated value, and prompting the user to reset the self-defined alarm threshold.

As an embodiment of the present invention, the operation module in step S4 includes an auto sampler, a column oven, and a detector; and the infusion pump module is used for stopping infusion of the infusion pump when liquid leakage is confirmed and waiting for follow-up examination. The CPU control logic for the infusion pump, autosampler, column oven and detector is shown in fig. 5-8.

As an implementation mode of the invention, the system repeatedly executes the processes of S1-S4 at a short time interval delta t, generally tens of milliseconds, so as to ensure that the real-time monitoring effect is achieved, and the judgment logics of the working module and the pump module adopt double judgment logics, after the CPU issues a command to close the functional component or stop the module from running, the workstation automatically executes the judgment logics once again to finish the processing.

No matter the current value of the liquid leakage sensor or the gas sensor exceeds a set threshold value, the leakage monitoring and alarm master control logic judges that leakage exists in the current system, at the moment, the workstation sends real-time alarm information to each module CPU and an infusion pump CPU (when leakage occurs, the infusion pump should stop infusion at first and wait for follow-up investigation), each module CPU starts a ventilation system according to respective characteristics, and gas containing organic steam is replaced at the first time to complete internal judgment and processing. In the processing mechanism, the invention adopts double closed loop judgment logic, namely, after the CPU issues a command to close the functional part or stop the module from running, the system automatically executes once more to confirm and finally completes the processing.

And according to the real-time monitoring data, when the current state is judged to be a non-leakage state, the alarm prompt of each module is released, the infusion pump module maintains the current state, and the rest modules are restored to the target state set by a user method, such as the temperature control of the column oven, the state restoration of the detector light source and the like.

Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the present invention in its spirit and scope. Are intended to be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.