Liquid adding control circuit and Kjeldahl apparatus liquid adding system

Abstract

The utility model provides a liquid adding control circuit and a Kjeldahl apparatus liquid adding system, the liquid adding control circuit comprises a liquid adding driving circuit, the liquid adding driving circuit provides a current used for driving a liquid adding pump motor, the liquid adding driving circuit further comprises a switch module, and the switch module is used for controlling on-off of the liquid adding driving circuit; the control circuit provides a control signal for controlling the switch-on or switch-off of the switch module; and the sampling circuit comprises a signal processing module and an acquisition end, the acquisition end is connected with the liquid adding driving circuit to acquire the current of the motor, and the signal processing module processes the acquired signal and inputs the signal to the control circuit. A liquid level sensor is replaced by detecting the current of the motor in cooperation with the switch module, and liquid adding operation on the solution barrel is more convenient. And in cooperation with a related model, the working state of the liquid adding pump can be diagnosed, and various unforeseen circumstances in the working process of an instrument can be effectively avoided.

Description

Technical Field

[0001] This application relates to the field of nitrogen analyzers, and more specifically, to a liquid addition control circuit and a liquid addition system for a Kjeldahl nitrogen analyzer. Background Technology

[0002] The Kjeldahl nitrogen analyzer is an instrument that calculates protein content by measuring the nitrogen content in a sample, based on the principle that the nitrogen content in proteins is constant. Because the method for measuring and calculating protein content is called the Kjeldahl method, it is called a Kjeldahl nitrogen analyzer. The Kjeldahl nitrogen determination experiment consists of four steps: digestion, distillation, absorption, and titration. The organic matter in the sample is digested into inorganic ammonium salts. Then, ammonia gas is released through distillation with the addition of alkali, and subsequently absorbed by an acidic solution. The acidic absorption solution is then titrated with a standard titrant to restore acidity. The endpoint is determined by color, and the nitrogen content is finally calculated based on the volume and concentration of the titrant consumed.

[0003] The distillation, absorption, and titration processes in the experiment require water, alkali, boric acid, and titrating acid reagents. The Kjeldahl nitrogen analyzer needs to transfer these reagents to the target container during the experiment. Existing technical solutions include... Figure 1 As shown. Existing technology uses a circuit board to drive a dispensing pump to transfer reagents from a solution tank to a target container; a level sensor positioned on the solution tank detects the liquid level, and the circuit board is connected to the level sensor via leads to acquire the level signal. The signal collected by the level sensor is then used to control the motor.

[0004] Using a liquid level sensor has the following disadvantages:

[0005] The liquid level sensor needs to be placed on the solution tank, and the installation of the liquid level sensor requires certain compatibility with the solution tank.

[0006] The liquid level sensor needs to be connected to the Kjeldahl nitrogen analyzer circuit board via a cable. The liquid level sensor cable needs to be disconnected when adding reagents to the solution tank, which is too cumbersome. Utility Model Content

[0007] The purpose of this application is to provide a liquid addition control circuit and a liquid addition system for a Kjeldahl nitrogen analyzer, so as to solve the above-mentioned problems existing in the prior art.

[0008] In a first aspect, a liquid addition control circuit is provided, comprising:

[0009] A liquid filling drive circuit provides current for driving a liquid filling pump motor. The liquid filling drive circuit also includes a switching module for controlling the on / off state of the liquid filling drive circuit.

[0010] A control circuit that provides control signals to control the switching module to be turned on or off;

[0011] The sampling circuit includes a signal processing module and a data acquisition terminal. The data acquisition terminal is connected to the liquid addition drive circuit to acquire the motor current. The signal processing module processes the acquired signal and inputs the signal to the control circuit.

[0012] In one optional embodiment, the control circuit includes a main control chip and an optocoupler module. The output terminal of the acquisition circuit is connected to the main control chip. The main control chip is connected to the light-emitting diode of the optocoupler module to control its brightness. The branch where the photosensitive receiver of the optocoupler module is located provides a current control signal to the switching module.

[0013] In one optional embodiment, the switching module is a MOS transistor, the gate of which is connected to the branch where the photosensitive receiver of the optocoupler module is located, and the source and drain are located in the liquid filling drive circuit.

[0014] In one optional implementation, the acquisition end includes a sampling resistor, the signal processing module is an operational amplifier, the sampling resistor is located in the liquid addition drive circuit, the operational amplifier amplifies the voltage across the sampling resistor, and the amplified voltage signal is connected to the main control chip.

[0015] In one optional embodiment, a freewheeling circuit is further included, the freewheeling circuit including a diode, the negative terminal of the diode being connected to the negative terminal of the motor, and the positive terminal being connected to the negative terminal of the motor.

[0016] In a second aspect, a liquid addition system for a Kjeldahl nitrogen analyzer is provided, including pipelines, a solution tank, a liquid addition pump, and a target container. The hot liquid pump is driven by a motor, and the liquid addition pump transfers the solvent in the solution tank to the target container through the pipelines, using the liquid control circuit described in the first aspect.

[0017] In one optional embodiment, the liquid pump is one of a diaphragm pump, peristaltic pump, gear pump, plunger pump, or centrifugal pump.

[0018] In one optional implementation, a display module is further included. The display module is connected to the main control chip and displays the status of the motor and pipelines based on the signals collected by the sampling circuit.

[0019] In one optional implementation, the display module displays the following messages: "Stop working", "Working status, pipeline unloaded", "Working status, pipeline blocked", "Working status, normal liquid addition", and "Working status, liquid addition pump disconnected".

[0020] In one optional embodiment, the system further includes a power supply module and a DC-DC converter. The power supply module provides the circuitry required for the motor and the photosensitive receiver, and the DC-DC converter converts the voltage provided by the power supply module into the operating voltage required by the control chip, the light-emitting diode, and the signal processing module.

[0021] The liquid addition control circuit of this application replaces the liquid level sensor with a switching module that detects the motor current, making the liquid addition operation of the solution tank more convenient. Combined with relevant models, it enables the diagnosis of the liquid addition pump's operating status, effectively preventing various unexpected situations during instrument operation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the liquid addition system of a Kjeldahl nitrogen analyzer in the prior art;

[0024] Figure 2 A schematic diagram of a liquid addition control circuit provided in an embodiment of this application;

[0025] Figure 3 This is a schematic diagram showing the connection of the main control chip in a liquid addition control circuit provided in an embodiment of this application;

[0026] Figure 4 A schematic diagram of a liquid addition system for a Kjeldahl nitrogen analyzer provided in this application embodiment;

[0027] Figure 5 This is a circuit diagram of the power supply module in a liquid addition system of a Kjeldahl nitrogen analyzer, provided as an embodiment of this application. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art. The words "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are only used to distinguish different components. The words "comprising" or "including," etc., mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but do not exclude other elements or objects. The words "connected," "coupled," or "connected," etc., are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application. Furthermore, the embodiments and features in the embodiments of this application can be combined with each other without conflict.

[0030] Figure 2 A liquid filling control circuit provided in this application includes a liquid filling drive circuit, a control circuit, and a sampling circuit. The liquid filling drive circuit provides current for driving a liquid filling pump motor. The liquid filling drive circuit also includes a switching module for controlling the on / off state of the liquid filling drive circuit. The liquid filling drive circuit is connected to a 24V voltage for the motor. The switching module is a MOSFET, with its source and drain located within the liquid filling drive circuit. The control circuit controls the start and stop of the motor by controlling the gate voltage of the MOSFET. Alternatively, a relay can be used instead of the MOSFET.

[0031] In addition, a freewheeling circuit is included, which comprises a diode with its negative terminal connected to the negative terminal of the motor and its positive terminal connected to the negative terminal of the motor. The freewheeling diode helps maintain the stability and reliability of the entire motor system.

[0032] The control circuit provides control signals to control the switching module's on or off state; the control circuit includes a main control chip and an optocoupler module. The main control chip is an STM32F103VCT6. Figure 3As shown, the output of the acquisition circuit is connected to the PC0 / ADC123_IN10 pin of the main control chip. The PB3 / JTDO / SPI3_SCK / I2S3_CK pins of the main control chip are connected to the light-emitting diode of the optocoupler module to control its brightness. The branch containing the photosensitive receiver of the optocoupler module provides a current control signal to the gate of the MOSFET.

[0033] The sampling circuit includes a signal processing module and a data acquisition terminal. The data acquisition terminal is connected to the liquid addition drive circuit to acquire the motor current. The signal processing module processes the acquired signal and inputs it to the control circuit. Specifically, the data acquisition terminal includes a sampling resistor, and the signal processing module is an operational amplifier. The sampling resistor is located in the liquid addition drive circuit, and the operational amplifier amplifies the voltage across the sampling resistor. The amplified voltage signal is then input to the main control chip.

[0034] The liquid addition control circuit of this application replaces the liquid level sensor with a switch module that detects motor current, making the liquid addition operation of the solution tank more convenient. Operators only need to write relevant programs into the main control chip to realize automatic switching of the switch and control the working status of the liquid addition pump.

[0035] Corresponding to the control circuit, embodiments of this application also provide a liquid addition system for a Kjeldahl nitrogen analyzer, such as... Figure 4 As shown, the system includes pipelines, a solution tank, a dispensing pump, and a target container. The hot liquid pump is driven by a motor. The dispensing pump transfers the solvent from the solution tank to the target container through the pipelines. The dispensing control circuit described above controls the dispensing of the hot liquid pump. The dispensing pump is one of a diaphragm pump, peristaltic pump, gear pump, plunger pump, or centrifugal pump.

[0036] The current of the liquid dosing pump under different operating conditions was tested. The current of the liquid dosing pump under different conditions is different and has a large degree of differentiation. The current correspondence table is as follows:

[0037]

[0038] By establishing a system model of the current under different operating conditions of the liquid filling pump, an effective diagnostic model for the liquid filling pump is realized, enabling real-time monitoring of the pump's status during testing. Based on different types of liquid filling pumps, other control relationships can be derived.

[0039] Therefore, this application can also include a display module connected to the main control chip. The display module displays the motor and pipeline status based on signals collected by the sampling circuit. The display module displays messages including "Stop working," "Working status, pipeline unloaded," "Working status, pipeline blocked," "Working status, normal liquid addition," and "Working status, liquid addition pump open circuit."

[0040] like Figure 5 As shown, it also includes a power supply module and a DC-DC converter. The power supply module provides the circuitry required for the motor and the photosensitive receiver, and the DC-DC converter converts the voltage provided by the power supply module into the operating voltage required by the control chip, the light-emitting diode, and the signal processing module.

[0041] The Kjeldahl nitrogen analyzer liquid addition system of this application relies on monitoring the working status and current of the liquid addition pump and comparing it with the system model to determine the working status of the liquid addition pump in real time. For example, if the working status of the liquid addition pump is "working, pipeline unloaded", it can be determined that the solution tank is low on liquid. Compared with existing technical solutions, the solution is simple and has no special requirements for the solution tank.

[0042] This liquid addition diagnostic system can detect the status of the liquid addition pump. The detection circuit is located inside the Kjeldahl nitrogen analyzer, and there is no need to install a liquid level sensor in the solution tank, making it more convenient to add liquid to the solution tank.

[0043] With the help of relevant models, the working status of the liquid pump can be truly diagnosed, which can effectively avoid various unexpected situations during instrument operation.

[0044] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims in this application and their equivalents, then this application also intends to include these modifications and variations.

[0045] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

Claims

1. A liquid adding control circuit characterized by comprising: The application relates to a liquid feeding control circuit. The liquid feeding control circuit comprises a liquid feeding driving circuit, a control circuit and a sampling circuit. The liquid feeding driving circuit provides a current for driving a liquid feeding pump motor, and further comprises a switch module for controlling the on-off of the liquid feeding driving circuit. The control circuit provides a control signal for controlling the on-off of the switch module.

2. The liquid loading control circuit of claim 1, wherein: The sampling circuit comprises a signal processing module and a sampling terminal.

3. The liquid loading control circuit of claim 2, wherein: The sampling terminal is connected to the liquid feeding driving circuit to collect the motor current.

4. The liquid loading control circuit of claim 2, wherein: The signal processing module processes the collected signal and inputs the signal into the control circuit.

5. The liquid loading control circuit of claim 2, wherein: The control circuit comprises a main control chip and a photo-coupler module.

6. A Kjeldahl apparatus liquid adding system, comprising a pipeline, a solution barrel, a liquid adding pump and a target container, the liquid adding pump is driven by a motor, the liquid adding pump transfers the solvent in the solution barrel to the target container through the pipeline, characterized in that: The output terminal of the sampling circuit is connected to the main control chip.

7. The liquid adding system of the Kjeldahl apparatus according to claim 6, wherein: The main control chip is connected to the light-emitting diode of the photo-coupler module to control the brightness of the light-emitting diode.

8. The liquid adding system of the Kjeldahl apparatus according to claim 6, wherein: The current control signal is provided to the switch module by the light-sensitive receiver branch of the photo-coupler module.

9. The liquid adding system of the Kjeldahl apparatus according to claim 8, wherein: The switch module is a MOS tube.

10. The liquid adding system of the Kjeldahl apparatus according to claim 7, wherein: The gate of the MOS tube is connected to the light-sensitive receiver branch of the photo-coupler module. The source and the drain of the MOS tube are located in the liquid feeding driving circuit. The sampling terminal comprises a sampling resistor. The signal processing module is an operational amplifier. The sampling resistor is located in the liquid feeding driving circuit. The operational amplifier amplifies the voltage between the two ends of the sampling resistor. The voltage signal after amplification is input into the main control chip. The liquid feeding control circuit further comprises a freewheeling circuit. The freewheeling circuit comprises a diode. The negative electrode of the diode is connected to the negative electrode of the motor. The liquid feeding control circuit further comprises a display module. The display module is connected to the main control chip. The display module displays the motor and pipeline state according to the signal collected by the sampling circuit. The display module displays the following contents: "stop working", "working state, pipeline empty", "working state, pipeline blocked", "working state, normal liquid feeding" and "working state, liquid feeding pump circuit breaking". The liquid feeding control circuit further comprises a power module and a DC-DC converter. The power module provides the required circuit for the motor and the light-sensitive receiver. The DC-DC converter converts the voltage provided by the power module into the working voltage required by the control chip, the light-emitting diode and the signal processing module.

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