A portable gas calibration device

Abstract

The utility model relates to gas detection technical field, the utility model provides a kind of portable gas calibration device, can realize portable flow adjustable, gas species selectable, configuration accurate, simple operation and safe use. The utility model device can produce five kinds of standard gas in hydrogen in air, hydrogen in oxygen, hydrogen in nitrogen, oxygen in hydrogen and oxygen in nitrogen, when producing hydrogen in air, can not use standard gas cylinder, by extracting field air after pretreatment as carrier gas to carry out gas distribution;When producing other gas, only need to be equipped with a bottle of carrier gas standard gas. The utility model gas distribution principle is simple, concentration is accurate, greatly facilitates the calibration of on-site analyzer, realizes portable flow adjustable, gas species selectable, configuration accurate, simple operation.

Description

Technical Field

[0001] This utility model relates to the field of gas detection technology, specifically to a portable gas calibration device. Background Technology

[0002] Existing calibration techniques for hydrogen and oxygen analyzers include two methods: one is to use standard gases in cylinders of various concentrations. This method involves multiple standard gas cylinders, which is inconvenient to carry, increases on-site safety hazards, and increases cylinder management costs. The other method is to use a dynamic gas mixing device to mix high-concentration gas into the required low-concentration gas. Although this method can reduce the number of cylinders, the concentration can be limited, the mixing accuracy cannot be guaranteed, and it involves high-concentration hydrogen standard gas, which increases certain safety hazards on-site.

[0003] It is evident that existing calibration technologies involve multiple standard gas cylinders, which are inconvenient to carry and pose safety hazards. Although some portable calibration devices have been designed, issues such as low gas mixing accuracy, small flow rate, requirement for on-site power supply, and unfriendly human-machine interface bring new problems to users, including inaccurate calibration and inconvenience. Moreover, some flammable and explosive environments with hydrogen alarms have strict management of the entry and exit of hydrogen standard gas cylinders. Therefore, there is an urgent need for a portable, adjustable concentration calibration device for calibrating on-site equipment. Utility Model Content

[0004] In view of this, the present invention provides a portable gas calibration device that is portable, has adjustable flow rate, selectable gas types, precise configuration, simple operation, and safe use.

[0005] To achieve the above objectives, this utility model proposes a portable gas calibration device, comprising: a gas path system, a control module, a power supply module, and a human-machine interaction module;

[0006] The gas path system includes an air branch, an electrolysis branch, and a mixed output branch;

[0007] The air branch includes a drying tube (26), a catalyst tube (27), an air pump (29), a drying and stabilizing bottle (28), and a first mass flow controller (32) connected in sequence, which are used to dehumidify, remove hydrogen, and stabilize the flow of the carrier gas.

[0008] The electrolysis branch includes an electrolytic cell (23), a water tank (22), a butterfly drying tube (24), and a second mass flow controller (31), which generates trace amounts of hydrogen or oxygen through SPE water electrolysis technology;

[0009] The mixed output branch mixes and outputs the gas from the air branch and the electrolysis branch through a three-way valve (35);

[0010] The control module includes a main control board (21), a constant current control board (19) and a pressure sensor. The main control board (21) dynamically adjusts the electrolysis current through a PID algorithm to maintain the pressure of the electrolysis branch at a set value.

[0011] The power module has a built-in battery pack (33) for powering the device;

[0012] The human-machine interface module includes an industrial serial port screen, which is used to set gas type, concentration, and flow parameters, and to display electrolysis current, flow rate, battery level, and alarm information in real time.

[0013] The gas mixing ratio between the air branch and the electrolysis branch is controlled collaboratively by the first mass flow controller (32) and the second mass flow controller (31), wherein:

[0014] The first mass flow controller (32) has a range of 500 mL / min and is used for carrier gas flow regulation;

[0015] The second mass flow controller (31) has a range of 50 mL / min and is used for regulating the flow rate of electrolytic gas.

[0016] The butterfly-shaped drying tube (24) of the electrolysis branch is equipped with a hydrophobic polytetrafluoroethylene waterproof and breathable membrane, and the water tank (22) is equipped with a water inlet for replenishing pure water.

[0017] The gas system pipeline is made of polytetrafluoroethylene, and a dry flow stabilizer bottle (28) is installed in the air branch to eliminate pressure fluctuations caused by gas resistance.

[0018] The device housing is designed with a roller box, with built-in shock-absorbing pads (5) and a battery compartment (3). The battery pack (33) has a capacity of 5Ah and supports continuous operation for more than 8 hours.

[0019] The device also includes a safety exhaust module, which controls the residual gas in the exhaust air path through a three-way solenoid valve, and the main control board (21) shuts down the system after the flow rate drops to zero.

[0020] Beneficial effects:

[0021] 1. This utility model device can generate five standard gases: hydrogen in air, hydrogen in oxygen, hydrogen in nitrogen, oxygen in hydrogen, and oxygen in nitrogen. When generating hydrogen in air, a standard gas cylinder is not required; pre-treated air is drawn from the site and used as the carrier gas for gas mixing. When generating other gases, only one standard carrier gas cylinder is needed. This utility model has a simple gas mixing principle and accurate concentration, greatly facilitating on-site calibration of the analyzer, and achieving portable, adjustable flow rate, selectable gas types, precise configuration, and simple operation.

[0022] 2. This utility model device uses an STM32 microcontroller as the main control chip. After power-on, the gas type, standard gas flow rate, and concentration value can be set via the screen. During gas production, the electrolytic cell is maintained in a stable, slightly positive pressure state, thereby ensuring a stable and accurate electrolytic gas flow rate.

[0023] 3. In this utility model device, the battery power, current flow rate, and electrolysis current can all be displayed on the screen.

[0024] 4. The device of this utility model adopts a roller box design, which is convenient to carry and can be calibrated without disassembling the analyzer. It has a built-in battery pack and can work continuously for more than 8 hours, achieving portability and long-lasting battery life.

[0025] 5. This utility model device has functions such as condensation filtration and hydrogen removal to ensure that the gas is clean; it adopts an industrial serial port screen to realize human-machine interaction, and has functions such as parameter setting, status viewing, fault and abnormal alarm and prompt. It is intelligently designed and easy to operate.

[0026] 6. This utility model device produces a variety of gases with a wide concentration range and high gas concentration accuracy. Different gas sources can be selected according to different usage scenarios to meet the needs of different users. It is safe, economical and reliable to use. The calibration process can be performed without or with only one bottle of standard gas, which reduces safety risks and economic costs. Attached Figure Description

[0027] Figure 1 This is an external view of a portable gas calibration device according to the present invention.

[0028] Figure 2 This is an internal design drawing of a portable gas calibration device according to the present invention. (a) is a front view of the internal layout of the gas calibration device, (b) is a rear view of the internal design of the gas calibration device, and (c) is a side view of the internal layout of the gas calibration device. Among them, 1-lining plate, 2-filter chamber, 3-battery chamber, 4-electrolytic cell bracket, 5-air pump shock absorber, 8-pressure block, 9-hand-tightening nail, 10, 11, 12, 13, 16-support block, 14-butterfly filter bracket, 15, 18-valve bracket, 17-air pump bracket, 19-constant flow control board, 20-power board, 21-main control board, 22-water tank, 23-electrolytic cell, 24-butterfly drying tube, 25, 30-three-way solenoid valve, 26-drying tube, 27-catalyst tube, 28-drying steady flow bottle, 29-air pump, 31-flow controller (50), 32-mass flow controller (500), 33-battery pack, 34-air pipe protective sleeve, 35-three-way valve.

[0029] Figure 3 This is a block diagram illustrating the gas path principle of a portable gas calibration device according to this utility model.

[0030] Figure 4 This is a gas path design diagram for a portable gas calibration device according to the present invention.

[0031] Figure 5 This is a block diagram of the internal structure of a portable gas calibration device according to the present invention.

[0032] Figure 6 This is a schematic diagram of the PID control principle for the pressure value of a portable gas calibration device according to this utility model.

[0033] Figure 7 This is a software flowchart of a portable gas calibration device according to the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] This utility model embodiment provides a portable gas calibration device, the appearance of which is as follows: Figure 1 As shown, the internal layout of the calibration device is as follows: Figure 2 As shown, it includes a liner 1, a filter chamber 2, a battery compartment 3, a pressure block 8, a hand-tightening nail 9, a constant flow control board 19, a power supply board 20, a main control board 21, a water tank 22, an electrolytic cell 23, a butterfly drying tube 24, a first three-way solenoid valve 25, a drying tube 26, a catalyst tube 27, a drying steady flow bottle 28, an air pump 29, a second three-way solenoid valve 30, a flow controller (50) 31, a mass flow controller (500) 32, a battery pack 33, and a three-way valve 35.

[0036] Liner 1 is used to fix various components; filter chamber 2 is used to house drying tube 26, catalyst tube 27, and drying stabilizer bottle 28. Filter chamber 2 is fixed by pressure block 8 and hand screw 9 and is located on the air branch. The air branch realizes the hydrogen removal and drying functions of air. After the gas path is branched by three-way valve 35, the gas is drawn by air pump 29. After stabilization, the flow is controlled by mass flow controller (500) 32. When using standard gas from a cylinder, no pretreatment is required and the flow is directly controlled. Three-way valve 35 is controlled by second three-way solenoid valve 30.

[0037] The battery compartment 3 is used to place the battery pack 33, which is used to power the whole machine. The power board 20 realizes power conversion. The main control board 21 realizes the electrical control of the flow controller (50) 31, the mass flow controller (500) 32 and the constant current control board 19, etc. The constant current control board 19 realizes constant current output control of electrolytic cell electrolysis.

[0038] On the electrolysis branch, the pure water in the water tank 22 is the water source for the electrolysis gas. The electrolysis cell bracket 4 is used to install the electrolysis cell 23. The electrolysis gas is dried through the butterfly drying tube 24. For safety reasons, the venting pipeline is equipped with a three-way solenoid valve 25. The flow is controlled by the flow controller (50) 31 and mixed with the carrier gas.

[0039] The device also includes a bracket, shock-absorbing pad, pressure block, fixing component, support block and protective sleeve, used to complete the installation and fixation and pipeline protection.

[0040] Specifically, the first fixing member 6 and the second fixing member 7 are used to fix the 32 mass flow controllers (500); Figure 2 The exhibition also showcases an electrolytic cell support 4, an air pump shock absorber 5, a first support block 10, a second support block 11, a third support block 12, a fourth support block 13, and a fifth support block 16; as well as a butterfly filter support 14, a first valve support 15, an air pump support 17, a second valve support 18, and an air pipe protective sleeve 34.

[0041] During calibration, this invention employs a dynamic volumetric method to prepare standard gas. It uses an electrochemical generation method—SPE water electrolysis technology—to produce trace amounts of hydrogen (oxygen) gas. Air, high-purity oxygen, or other gases are used as the carrier gas. By controlling the magnitude of the SPE electrolysis current, trace amounts of gas are produced and mixed to form the standard gas. This embodiment of the device uses an STM32 microcontroller as the main control chip. After power-on, the gas type, standard gas flow rate, and concentration value are set via the screen. During gas production, the electrolytic cell is maintained at a stable, slightly positive pressure to ensure a stable and accurate electrolytic gas flow rate. Battery level, current flow rate, and electrolysis current are all displayed on the screen.

[0042] When hydrogen is generated in the air, the pretreated air is pumped to mass flow controller 1 and mixed with hydrogen electrolyzed by the electrolyzer controlled by mass flow controller 2 to produce standard gas. When hydrogen in oxygen, hydrogen in nitrogen, oxygen in hydrogen, and oxygen in nitrogen are generated, the cylinder gas controlled by mass flow controller 1 is mixed with the electrolyzed gas controlled by mass flow controller 2 to produce standard gas. The gas circuit principle block diagram is as follows. Figure 3 .

[0043] Specific gas path design such as Figure 4As shown. When air is used as the carrier gas, the carrier gas path is designed to sequentially pass through a three-way solenoid valve 1, a drying tube, a catalyst, an air pump, a three-way solenoid valve 2, a drying and stabilizing bottle, a mass flow controller-500, and a three-way valve. The drying tube is used to dehumidify the air; the catalyst removes hydrogen from the dried air; and the drying and stabilizing bottle eliminates negative pressure, filters water generated during the hydrogen removal process, and maintains stable airflow. The electrolytic gas branch includes an electrolytic cell, a water tank, a butterfly drying tube, a three-way solenoid valve 3, a mass flow controller-500, and a three-way valve. The electrolytic cell generates electrolyzed hydrogen and oxygen. The water tank stores pure water and transmits the electrolyzed gas through the gas path interface. The butterfly drying tube primarily dries the electrolyzed gas. A hydrophobic PTFE waterproof and breathable membrane is installed inside the butterfly drying tube to prevent water from the water tank from leaking out with the electrolyzed gas when the equipment is tilted.

[0044] In addition to the water and gas connectors to the electrolytic cell, the water tank also has a water inlet at the top, making it convenient to add water when the pure water in the tank runs out.

[0045] The internal structural block diagram of this utility model device is as follows: Figure 5 As shown, an external 220V AC power supply can charge the battery, which has a capacity of 5Ah, enough to meet the device's continuous operation for 8 hours. The constant current control board completes the constant current output of the electrolytic cell section; the pressure sensor completes pressure detection; the mass flow controller completes the flow control of the carrier gas and electrolytic gas; the screen can be used to set relevant parameters of the generated gas and display the device status; the main control board completes the control of the constant current control board, the air pump, the solenoid valve, and the screen drive.

[0046] To ensure the stability of the standard gas outflow, the device in this embodiment uses polytetrafluoroethylene gas pipes for the internal pipelines, adds a gas stabilizer bottle, and automatically controls the electrolysis current of the electrolytic cell.

[0047] Specifically, gas resistance occurs when gas flows within a pipeline, and this resistance is related to pipeline length, inner wall roughness, flow velocity, and fluid density. Polytetrafluoroethylene (PTFE) gas pipes have smooth inner walls and extremely low friction, making them less prone to material adhesion. This reduces gas resistance. Because the carrier gas branch has many components and a long pipeline, gas resistance can lead to a decrease in pressure at the carrier gas branch outlet, causing unstable flow control. Adding a flow stabilizer bottle before the mass flow controller in the carrier gas branch ensures stable gas flow and prevents internal pressure fluctuations and oscillations. The stability of the electrolytic gas branch flow depends on the magnitude of the electrolytic current in the electrolytic cell and the dynamic adjustment of the generated flow. Adding a pressure sensor to the pipeline, using the electrolytic current as input and the pressure as output, allows for closed-loop dynamic adjustment, achieving stable pressure control.

[0048] In this utility model device, the pressure value PID control principle is specifically implemented as follows: Figure 6As shown. Set the pressure to 130 kPa to ensure the electrolytic gas pressure entering the mass flow controller is stable and maintains a slightly positive pressure. After powering on the device, first check if the device is functioning correctly, including the water tank and drying tube. If the drying tube turns pink, replace the desiccant; if the water tank is low on water, add water. Once the device is functioning correctly, set the calibration-related parameters, such as gas source type, gas flow rate, and gas type. After setting, check that the calibrator and the device being calibrated are connected correctly, then set different concentration points for calibration. After calibration, to ensure safety, purge the gas from the device before powering it off.

[0049] The software flowchart of the device is as follows Figure 7 As shown. After setting the relevant gas parameters, complete the analyzer calibration operation on the calibration page. Input the gas concentration, and after clicking the "Start" button on the calibration page, the PID control of the electrolyzer current begins, performing closed-loop control of the electrolysis current based on the real-time pressure in the electrolysis gas branch pipeline. If the carrier gas is set to pump air, start the pump and automatically adjust the mass flow controllers of the carrier gas and electrolysis gas to the same flow rate as the set concentration; after clicking the "Stop" button, the pump turns off, the electrolysis current is set to minimum, and the mass flow controllers of the carrier gas and electrolysis gas are turned off. When the current flow rate and current concentration meet the calibration requirements, the analyzer can be calibrated. If multiple calibration points are required, the next concentration can be set after calibrating one calibration point, and the above process can be repeated. After calibration, after clicking the "Exhaust" button, the electrolysis current is set to minimum, the electrolysis gas MFC is opened to maximum (50mL), the pump turns off, and the carrier gas MFC is turned off. The analyzer can be shut down when the current flow rate is near 0, as indicated by the screen reading. If you want to continue the analyzer calibration after pressing the "exhaust" button, you need to turn off and restart the device.

[0050] The calibration steps based on the portable gas calibration device described in this utility model are as follows:

[0051] Step 1: Device Initialization and Self-Test

[0052] 1.1 Power on the device and start it up. The main control board 21 performs system initialization and displays the battery level, gas circuit status and component self-test results on the screen.

[0053] 1.2 Check the status of key components:

[0054] Color detection of desiccant tube 26: If the desiccant is ineffective (e.g., turns pink), it should be replaced.

[0055] Water level 22 in water tank: If water is low, add pure water through the water inlet;

[0056] Gas line sealing test: Verify whether there is a leak in the pipeline using a pressure sensor.

[0057] 1.3 After confirming that there are no abnormal alarms from the device, enter the parameter setting interface.

[0058] Step 2: Gas Parameter Settings

[0059] 2.1 Select the type of gas to be calibrated (hydrogen in air, hydrogen in oxygen, hydrogen in nitrogen, oxygen in hydrogen, oxygen in nitrogen) via the screen.

[0060] 2.2 Set the target concentration value and total output flow rate.

[0061] 2.3 Select the carrier gas source based on the type of gas chosen:

[0062] If the carrier gas is air: activate the air pump 29 to draw in ambient air, dehumidify it through the drying tube 26, remove hydrogen through the catalyst tube 27, and stabilize the flow through the drying and stabilizing bottle 28;

[0063] If the carrier gas is cylinder gas (such as high-purity nitrogen, oxygen, or hydrogen): turn off the gas pump and connect directly to the cylinder gas line.

[0064] 2.4 Save the settings after confirming that the parameters are correct.

[0065] Step 3: Gas generation and flow control

[0066] 3.1 Start-up of electrolytic cell 23:

[0067] The constant current control board 19 calculates the electrolysis current based on the target concentration and starts the SPE water electrolysis to generate trace amounts of H or O.

[0068] The electrolytic gas is dried by the butterfly drying tube 24 before entering the mass flow controller.

[0069] 3.2 Carrier gas flow rate adjustment:

[0070] Mass flow controller (500) 32 controls the carrier gas flow rate, and mass flow controller (50) 31 controls the electrolytic gas flow rate. The two are mixed in proportion to generate standard gas.

[0071] The main control board 21 monitors the total flow rate of the mixed gas in real time and dynamically adjusts the electrolysis current through a PID algorithm to maintain the pressure in the electrolysis branch at a stable 130 kPa (see...). Figure 6 ).

[0072] 3.3 The screen displays real-time parameters: electrolysis current, carrier gas flow rate, electrolysis gas flow rate, current concentration, and battery power.

[0073] Step 4: Calibration Execution

[0074] 4.1 Connect the analyzer to be calibrated to the device output port and ensure the gas path is sealed.

[0075] 4.2 Click the “Start Calibration” button. The device will enter a stable state and continuously output standard gas.

[0076] 4.3 When the screen displays that the current concentration deviates from the target concentration by ≤±1% and the flow rate is stable, record the reading of the analyzer being calibrated to complete the single-point calibration.

[0077] 4.4 If multiple calibrations are required: Return to step 2 to adjust the target concentration, and repeat steps 3-4 until all calibration points are covered.

[0078] Step 5: Calibration complete and safety venting

[0079] 5.1 Click the "Stop" button to turn off the electrolytic cell (the electrolytic current drops to the minimum value) and stop the air pump (if using air carrier gas).

[0080] 5.2 Perform safety venting:

[0081] Open the three-way solenoid valve to purge the residual gas in the pipeline;

[0082] When the flow rate monitored on the screen drops to near zero, it confirms that there is no residue in the gas path.

[0083] 5.3 Turn off the power to the device, remove the analyzer to be calibrated, and complete the calibration process.

[0084] In summary, the above are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A portable gas calibration device, characterized in that, include: Pneumatic system, control module, power supply module, and human-machine interface module; The gas path system includes an air branch, an electrolysis branch, and a mixed output branch; The air branch includes a drying tube (26), a catalyst tube (27), an air pump (29), a drying and stabilizing bottle (28), and a first mass flow controller (32) connected in sequence, which are used to dehumidify, remove hydrogen, and stabilize the flow of the carrier gas. The electrolysis branch includes an electrolytic cell (23), a water tank (22), a butterfly drying tube (24), and a second mass flow controller (31), which generates trace amounts of hydrogen or oxygen through SPE water electrolysis technology; The mixed output branch mixes and outputs the gas from the air branch and the electrolysis branch through a three-way valve (35); The control module includes a main control board (21), a constant current control board (19) and a pressure sensor. The main control board (21) dynamically adjusts the electrolysis current through a PID algorithm to maintain the pressure of the electrolysis branch at a set value. The power module has a built-in battery pack (33) for powering the device; The human-machine interface module includes an industrial serial port screen, which is used to set gas type, concentration, and flow parameters, and to display electrolysis current, flow rate, battery level, and alarm information in real time.

2. The portable gas calibration device according to claim 1, characterized in that, The gas mixing ratio between the air branch and the electrolysis branch is controlled collaboratively by the first mass flow controller (32) and the second mass flow controller (31), wherein: The first mass flow controller (32) has a range of 500 mL / min and is used for carrier gas flow regulation; the second mass flow controller (31) has a range of 50 mL / min and is used for electrolytic gas flow regulation.

3. The portable gas calibration device according to claim 1 or 2, characterized in that, The butterfly-shaped drying tube (24) of the electrolysis branch is equipped with a hydrophobic polytetrafluoroethylene waterproof and breathable membrane, and the water tank (22) is equipped with a water inlet for replenishing pure water.

4. The portable gas calibration device according to claim 3, characterized in that, The pipeline of the gas system is made of polytetrafluoroethylene, and a dry flow stabilizer bottle (28) is installed in the air branch to eliminate pressure fluctuations caused by gas resistance.

5. The portable gas calibration device according to claim 1, 2, or 4, characterized in that, The device housing adopts a roller box design, with built-in shock-absorbing pads (5) and battery compartment (3). The battery pack (33) has a capacity of 5Ah and supports continuous operation for more than 8 hours.

6. The portable gas calibration device according to claim 1, 2 or 4, characterized in that, The device also includes a safety exhaust module, which controls the residual gas in the exhaust air path through a three-way solenoid valve, and the main control board (21) shuts down the system after the flow rate drops to zero.

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