CN102698645B - Calibrating gas automatic mixing system - Google Patents
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- CN102698645B CN102698645B CN201210173222.4A CN201210173222A CN102698645B CN 102698645 B CN102698645 B CN 102698645B CN 201210173222 A CN201210173222 A CN 201210173222A CN 102698645 B CN102698645 B CN 102698645B
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- 238000002156 mixing Methods 0.000 title claims abstract description 24
- 238000009826 distribution Methods 0.000 claims abstract description 20
- 238000001514 detection method Methods 0.000 claims abstract description 8
- 238000002360 preparation method Methods 0.000 claims abstract description 7
- 239000007789 gas Substances 0.000 claims description 89
- 239000012159 carrier gas Substances 0.000 claims description 15
- 230000002950 deficient Effects 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 2
- 238000012545 processing Methods 0.000 claims description 2
- 238000012360 testing method Methods 0.000 abstract description 4
- 238000002955 isolation Methods 0.000 abstract description 3
- 238000000034 method Methods 0.000 description 13
- 230000008569 process Effects 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 6
- 230000003750 conditioning effect Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000003556 assay Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004587 chromatography analysis Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000012372 quality testing Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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Abstract
The present invention relates to a kind of gas mixing ratio system, especially a kind of calibrating gas automatic mixing system that can carry out closed-loop control under atmospheric pressure at room condition.Adopt and automatically control distribution principle, control gas flow by mass flow controller, the calibrating gas of preparation variable concentrations, infrared gas detection module carries out Concentration Testing to gas in mixed gas tank, the voltage signal detected is fed back to single-chip microcomputer, compares with setting value, thus finely tune; The I/O mouth of single-chip microcomputer exports control signal, and after light-coupled isolation drives, the switching of control relay, by the switching of Control contactor, and then the opening of control pump, to stop; Configure check-valves in pipeline, prevent gas backflow.Automaticity of the present invention is high, and institute's gas distribution precision is high, concentration range is wide, uniformity good.
Description
Technical field
The present invention relates to a kind of gas mixing ratio system, especially a kind of calibrating gas automatic mixing system that can carry out closed-loop control under atmospheric pressure at room condition.
Background technology
Along with the fast development of China's economy and science and technology, calibrating gas is as the measurement criteria of gas componant value, be widely used in the industries such as oil, chemical industry, metallurgy, electronics, environmental protection, colliery and metering, the effect playing unique specification and ensure the quality of products, can produce huge economic benefit and social benefit.Calibrating gas has stability, uniformity and the large feature of accuracy three, indispensable important function is played in instrument and meter calibrating with calibration, analysis test method evaluation, atmospheric environment pollution monitoring, health care and clinical assay and gas products quality control etc., calibrating gas demand increases day by day, and quality requirement significantly improves.
The preparation method of calibrating gas is divided into static volumetric method and Devince By Dynamic Gas Ration Method: static volumetric method is that a certain amount of Primordial Qi is added in the container of known volume, and then add the carrier gas that purified treatment crosses, mixing stirs evenly, according to adding Primordial Qi, the amount of carrier gas and volume of a container, the concentration of gas can be calculated.Devince By Dynamic Gas Ration Method be by the Primordial Qi of concentration known with less flow, invariable send in gas mixer, the carrier gas crossed of purified treatment with larger flow, invariable send in gas mixer, carry out mixing being diluted with raw-gas, the ratio (extension rate) of the flow of Measurement accuracy Primordial Qi, carrier gas, calculate the concentration of calibrating gas, the ratio of fine adjustment gas flow can obtain the calibrating gas of desired concn.
At present, domestic most employing gravimetric method preparing calibrating gas, due to the restriction by production technology, production equipment, the calibrating gas uncertainty obtained is large, poor stability, concentration not accurately maybe can not realize continuous automatic distributing, cannot meet the needs of actual production.The level of external distribution is led over domestic, and its quality testing department, manufacturing enterprise etc. all have Standard Gases automated gas divider, but expensive, complex structure, domestic most enterprise, department cannot accept, and can not carry out comparatively extensive use.Traditional time required for gas chromatographic technique testing gas concentration is longer, is difficult to reach the requirement detected in real time.Therefore, in real time, dynamically the development of continuous print air distribution system seems very important.
Summary of the invention
The technical scheme that the present invention will solve: solve in calibrating gas proportioning process, cannot continuously, automatic distributing, the calibrating gas of configuration mixes the problems such as uneven, concentration is accurate not.
The technical solution adopted in the present invention is: calibrating gas automatic mixing system, carries out closed-loop control in this system.Host computer (PC) selects distribution kind (as methane, carbon monoxide), and setting needs the gas concentration value of preparation, then order is sent to slave computer (single-chip microcomputer); Through single-chip microcomputer analyzing and processing, outputting standard voltage signal, to mass flow controller (MFC), controls the aperture (comprising Primordial Qi and carrier gas) of output solenoid valve, reaches the object controlling gas flow; The feedback voltage signal of single-chip microcomputer sampling quality flow controller, makes the stable output of gas flow, enters the mixing of mixed gas tank, closed-loop control in realizing.
After Homogeneous phase mixing, gas will to be mixed in gas tank and will send into infrared gas detection module, carry out Concentration Testing, the data detected and voltage signal corresponding to concentration will be fed back to single-chip microcomputer.Compare with setting value, the strict flow controlling unstripped gas and carrier gas, if defective, carry out finely tuning (adjustment Primordial Qi or carrier gas air inlet), realize outer closed-loop control; If qualified, then normal mixture body squeezed into and specify gas cylinder (steel cylinder).
The voltage signal that the D/A mouth of microcontroller (single-chip microcomputer) exports exports to the size that mass flow controller controls gas circuit flow after conditioning, the feedback analog voltage signal that flow is corresponding simultaneously, through the conditioning of RC LPF, voltage follow and difference scale operation, receive the A/D mouth of microcontroller (single-chip microcomputer).
The I/O mouth of microcontroller (single-chip microcomputer) exports control signal, after light-coupled isolation drives, and the switching of control relay, and then the open and close of Controlling solenoid valve; By the switching of Control contactor, and then the opening of control pump, to stop, make distribution process increasingly automated.
Configure Pressure gauge in pipeline, Real-Time Monitoring is carried out to pressure; Configuration check-valves, prevents gas backflow, ensures the precision of distribution, the security of process.
At mixed gas tank air inlet, adopt a road to be divided into two tunnels respectively to Primordial Qi and carrier gas, gas is shunted, 20 degree of direction air inlets are become downwards along mixed cylinder walls tangent line, gas is entered after tank can High Rotation Speed, increases the disturbance of gas, makes the gas Quick uniform mixing entered in tank.
Beneficial effect of the present invention: what control due to mass flow controller is the mass flow of gas reality, instead of volume flow, therefore, the standard gas concentration of preparation will not be subject to the impact of environment, temperature and pressure change, all applicable to the Standard Gases of the high and low concentration of preparation, there is good using value.Infrared gas detection module detects in real time to mixed gas concentration, and the data detected are sent to single-chip microcomputer, realizes closed-loop control, ensures, improves distribution precision.This Standard Gases automatic mixing system, distribution speed is fast, automaticity is high, decreases the interference of human factor, monitors in real time, ensure that industrial continuity and reliability, thus improves production automation degree, production efficiency; Institute joins that calibrating gas precision is high, concentration range is wide, uniformity is good, cost is low.
Accompanying drawing explanation
Fig. 1 is simple gas circuit schematic diagram of the present invention;
Fig. 2 is overall flow figure of the present invention;
Fig. 3 is circuit design schematic diagram of the present invention;
Fig. 4 is Fundamentals of Mono-Chip Computers figure of the present invention;
Fig. 5 is relay of the present invention, pump control chart;
Fig. 6 is PC interface of the present invention and burden control flow process;
Fig. 7 is mixed gas tank air inlet figure of the present invention.
Detailed description of the invention
As described in Figure 1, in simple pneumatic diagram, switching control panel provides signal, Controlling solenoid valve, mass flow controller, carry out gas path on-off, flow-control respectively, and then make Primordial Qi and carrier gas enter mixed gas tank in proportion, after Homogeneous phase mixing, fill gas cylinder, complete distribution.
As described in Figure 2, air enters through screw pump, after filtration, drying, a series of process of constant temperature, obtains pure air (carrier gas); Primordial Qi adopts 99.999% pure steel cylinder gas.Before distribution, first to drive vavuum pump, vacuum pumping is carried out to gas circuit, blending tank, improve distribution precision, quality.
Host computer (PC) sends a command to slave computer (single-chip microcomputer); Single-chip microcomputer receives order, processes by analysis, and outputting standard voltage signal, to mass flow controller (MFCA, MFCB), controls the flow output of Primordial Qi, carrier gas; The feedback voltage signal of single-chip microcomputer sampling quality flow controller, makes two-way gas stability of flow export simultaneously, and closed-loop control in realizing, makes two-way gas flow enter blending tank in proportion.
When pressure sensor detects that in blending tank, gas pressure is higher than a certain higher limit, distribution stops.To wait in tank after gas uniform mixing, gas is sent into infrared gas detection module, carry out Concentration Testing, by the concentration corresponding voltage signal feedback that collects to control unit (single-chip microcomputer).Compare with setting value, if defective, finely tune; If qualified, then open oilless (oil free) compressor, booster pump, oilless (oil free) compressor produces and drives air, promotes booster pump work, is squeezed into by normal mixture body and specifies gas cylinder (steel cylinder), realize full-automatic distribution.When gas pressure in blending tank is lower than a certain lower limit, restarts air distribution system, repeat said process.Meanwhile, in pipeline, configure magnetic valve, break-make control is carried out to gas circuit; Configuration Pressure gauge, carries out Real-Time Monitoring to pressure; Configuration check-valves, prevents gas backflow, ensures the precision of distribution, the security of process.
As described in Figure 3, the present invention is the dynamic auto air distribution system based on C8051F020 single-chip microcomputer and PC control technology, comprise PC (main frame and touch display screen), micro controller unit (the minimum system of C8051F020 single-chip microcomputer: CPU, power supply, crystal oscillating circuit, jtag interface circuit, the wire jumper etc. of LCD indicator lamp and necessity), communications interface unit (RS-232 drive circuit), display unit (LCD liquid crystal display circuit), (the conditioning of analog signal of mass flow control unit, the control of mass flow), control unit (the magnetic valve of relay and pump, the isolated drive circuit of pump) and detection alarm unit (pressure sensor, infrared gas detection module and sound light alarming circuit) etc.
PC, C8051F020 single-chip microcomputer are connected by driving chip MAX232 by described communications interface unit; Described display unit is connected with the I/O mouth of microcontroller; Described mass flow control unit controls the size of flow, the voltage signal exported by the D/A mouth of microcontroller exports to mass flow controller to control the size of gas circuit flow after conditioning, the feedback analog voltage signal that flow is corresponding simultaneously, through the conditioning of RC LPF, voltage follow and difference scale operation, be connected with microcontroller by A/D mouth; Described relay and the controller unit of pump export control signal by the I/O mouth of C8051F020 single-chip microcomputer, gone the switching of control relay by optical couple isolation drive circuit, so Controlling solenoid valve, pump work; Described detecting unit comprises pressure sensor, infrared gas detection module and sound light alarming circuit.
As described in Figure 4, micro controller unit CPU adopts the C8051F020 single-chip microcomputer of CYGNAL company, and emulator is connected with single-chip microcomputer by JTAG emulation interface.Power module adopts the Switching Power Supply of 12V to convert+5V to through L7805 three terminal regulator, and voltage transitions adopts the 5V/3V high-performance voltage stabilizing chip TPS7333Q of TI company to convert+5V to+3.3V for single-chip microcomputer.Reset circuit and crystal oscillator (22.1184MHZ) respectively with MCU /RST pin is connected with XTAL1, XTAL2 pin, when S key is pressed, System recover is to original state; 5,4,7,6 pins of JTAG are connected with TMS, TCK, TDI, TDO pin of C8051F020 respectively, and 1 pin connects 3.3V voltage, and 2,3,9 pin altogether.
As described in Figure 5, the control signal of the P4.0-P4.4I/O mouth output of C8051F020 isolates the switching of rear control relay and then the open and close of Controlling solenoid valve respectively through optocoupler TIL113; The control signal that P5.0-P5.3I/O mouth exports isolate respectively through optocoupler TIL113 after the switching of control relay, by the switching of Control contactor, and then the opening of control pump, to stop.
As described in Figure 6, Standard Gases automatic mixing PC administration interface comprises system maintenance, proportioning management, data base administration etc.Wherein, first will carry out distribution kind (as methane, carbon monoxide) in proportioning management and select, next sets matched proportion density, and then opens serial ports transmission order, and time delay waits for that the finish command beamed back by single-chip microcomputer, completes distribution.
As described in Figure 7, mixed gas tank air inlet, a road is adopted to be divided into two tunnels respectively to Primordial Qi and carrier gas, gas is shunted, 20 degree of direction air inlets are become downwards along mixed cylinder walls tangent line, gas is entered after tank can High Rotation Speed, increases the disturbance of gas, makes the gas Quick uniform mixing entered in tank.
Claims (1)
1. a calibrating gas automatic mixing system, upper computer selecting distribution kind, setting needs the gas concentration value of preparation, then order is sent to slave computer, through the C8051F020 single-chip microcomputer analyzing and processing that CYGNAL company produces, outputting standard voltage signal is to mass flow controller, control the aperture of output solenoid valve, it is characterized in that: the feedback voltage signal of C8051F020 single-chip microcomputer sampling quality flow controller, control the stable output of gas flow, enter the mixing of mixed gas tank, closed-loop control in realizing; Simultaneously after Homogeneous phase mixing, infrared gas detection module is adopted to detect the concentration of gas in mixed gas tank, the data detected and voltage signal corresponding to concentration are fed back to single-chip microcomputer, compare with setting value, the strict flow controlling unstripped gas and carrier gas, if defective, adjustment Primordial Qi or carrier gas air inlet are finely tuned, realize outer closed-loop control, if qualified, then normal mixture body is squeezed into appointment gas cylinder; Mixed gas tank air inlet, is divided into two tunnels in a road respectively to Primordial Qi and carrier gas, shunts gas, become 20 degree of direction air inlets downwards along mixed cylinder walls tangent line; Described calibrating gas adopts flow, the double-closed-loop control of concentration is prepared, and adopts the standard gas concentration of the double-closed-loop control preparation of flow, concentration not to be subject to the impact of environment, temperature and pressure change.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210173222.4A CN102698645B (en) | 2012-05-30 | 2012-05-30 | Calibrating gas automatic mixing system |
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| CN201210173222.4A CN102698645B (en) | 2012-05-30 | 2012-05-30 | Calibrating gas automatic mixing system |
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| CN102698645A CN102698645A (en) | 2012-10-03 |
| CN102698645B true CN102698645B (en) | 2016-02-10 |
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