CN104142377A - Low-cost gas path system of gas chromatograph and achieving method of low-cost gas path system - Google Patents
Low-cost gas path system of gas chromatograph and achieving method of low-cost gas path system Download PDFInfo
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- CN104142377A CN104142377A CN201410339544.0A CN201410339544A CN104142377A CN 104142377 A CN104142377 A CN 104142377A CN 201410339544 A CN201410339544 A CN 201410339544A CN 104142377 A CN104142377 A CN 104142377A
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- 238000000034 method Methods 0.000 title claims description 9
- 239000007789 gas Substances 0.000 claims abstract description 108
- 238000010926 purge Methods 0.000 claims abstract description 63
- 239000012159 carrier gas Substances 0.000 claims abstract description 22
- 238000002347 injection Methods 0.000 claims description 16
- 239000007924 injection Substances 0.000 claims description 16
- 238000005259 measurement Methods 0.000 claims description 4
- 230000007613 environmental effect Effects 0.000 claims description 3
- 238000012937 correction Methods 0.000 abstract description 8
- 238000010586 diagram Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 230000001915 proofreading effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000012284 sample analysis method Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
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Abstract
A gas path system of a gas chromatograph comprises a carrier gas flowing-in gas path, a purging flowing path and a dividing gas path, wherein the carrier gas flowing-in gas path is used for pushing a pneumatolytic sample in a sample inlet to a gas chromatographic column, and the purging flowing path and the dividing gas path are communicated with the sample inlet. The purging flowing path is provided with a pressure sensor used for measuring the chapiter pressure of the sample inlet, the back of the pressure sensor is connected with a proportional valve C used for controlling the purge gas flow rate, and the back end of the proportional valve C is directly connected to the atmosphere. According to the gas path system, the characteristics of the proportional valve used in the purging flowing path is calibrated, the needed proportional valve coil current is worked out according to the pressure of the two ends of the proportional valve in the purging flowing path and the set purge gas flow rate, correction is carried out through the current temperature, a current output part of a circuit board drives the proportional valve, and the purging flow rate is controlled in an open-loop mode. On the premise that the system application range and enough precision are guaranteed, one pressure sensor and a gas resistor are omitted in a purging gas path, and the cost of the whole gas path system is effectively reduced.
Description
Technical field
The invention belongs to analytical chemistry, fluid control field, be specially a kind of air-channel system and implementation thereof of gas chromatograph cheaply.
Background technology
Gas chromatograph is used for potpourri to analyze in analytical chemistry, and carrier gas (being generally inert gas) is pushed into the sample having gasified in injection port in gas chromatographic column, and in flow process, produces separated.In order to guarantee accurately qualitative, the quantitation capabilities of gas chromatograph, in the flow control circuit of gas, guarantee split ratio and column cap pressure accurately.
Control system in existing typical carrier gas stream comprises 3 proportioning valves, 3 sensors and a vapour lock, and cost is very high.In typical case's application of gas chromatograph, the gas flow that purges stream is lower, and be generally constant, a conventional purge gas flow is 3mL/min, and correspondingly, carrier gas flows into flow in gas circuit can reach 1000ml/min, therefore need to select range to be greater than the flow sensor of 1000mL/min, typical accuracy of flow sensor is range 1%, and carrier gas flows into deviation and can reach 10mL/min left and right.In shunting gas circuit, controlling target is that column cap is pressed, and the actual bypass flow passing through is that carrier gas inflow total flow deducts chromatographic column flow and purge flow rate.Ratios affect between bypass flow and chromatographic column flow is to split ratio, and further have influence on the quantitative accuracy of gas, in this sense, the specified deviation of flow that only need to purge stream is less than carrier gas and flows into 1/3 of specified deviation, quantitation capabilities that just can appreciable impact gas chromatograph.The object of purge gas is that gasification and the fragment that falls in diaphragm pad are blown out, so gas flow has lower limit, can guarantee that by the ratings of suitable raising purge flow rate purge flow rate is not less than lower limit within the scope of nominal error.
In sum, after suitably improving purge flow rate ratings (as adjusting to 4～6mL/min), the specified deviation of uninterrupted that purges stream reaches 50%, also substantially can not affect the performance of instrument.Therefore, sacrifice the flow control accuracy that a part purges gas circuit, can on the basis that guarantees systematic analysis performance, effectively reduce the cost of air-path control system.
For lowering apparatus cost, in the middle-end gas chromatograph 7820 of Anjelen Sci. & Tech. Inc's design research and development, adopted the fixedly mode of vapour lock, in purging stream, simplified controlling unit, reduced a proportioning valve and pressure transducer, only stay next vapour lock.But owing to there is no proportioning valve, this stream control mode causes purge gas flow completely uncontrollable, but column cap in concrete sample analysis method is pressed and is obtained passively.When column cap is pressed when 1 psi gauge pressure becomes 100 psi gauge pressure, the flow by vapour lock changes can be up to 800 times.Therefore, in actual analysis method, there will be when the column cap pressure of setting is very low, sweep gas flow is very little, can not meet the needs of removing injection port diaphragm pad from pollution, and when column cap pressure is larger, purge flow rate is excessive, cause the problems such as sample leaks, and relatively large deviation appears in split ratio, carrier gas total flow lower limit limited (must be greater than purge flow rate).Therefore, this purge stream pipelines control structure can only be used in very narrow column cap and press scope, has greatly limited analyst coverage and the method for instrument.And if under the prerequisite that can not have obviously to reduce in system performance, reduce proportioning valve, sensor or the quantity of vapour lock, just can reduce the cost of whole air-path control system, raising product competitiveness.
Summary of the invention
Under the prerequisite that the object of the invention is not have obviously to reduce in the performance that guarantees whole air-channel system, reduce proportioning valve, sensor or the quantity of vapour lock to reduce the cost of whole air-path control system, improve product competitiveness.
To achieve these goals, technical matters solved by the invention realizes by the following technical solutions:
An air-channel system for gas chromatograph cheaply, comprises purging stream and shunting gas circuit that carrier gas that sample for injection port has been gasified is pushed into gas chromatographic column flows into gas circuit, connects with injection port; Described carrier gas flows between gas circuit and injection port proportioning valve A and flow sensor is installed; In described shunting gas circuit, be provided with one and be used for the proportioning valve B to setting value by column cap pressure-controlled, proportioning valve B rear end is directly connected in atmosphere; The pressure transducer that a column cap that is used for measuring injection port is pressed is installed in described purging stream, after pressure transducer, be connected with a proportioning valve C who is used for controlling purge gas flow, proportioning valve C rear end is directly connected in atmosphere, and the gas flow purging in gas circuit is controlled to employing open loop control mode.
A kind of implementation of air-channel system of gas chromatograph is cheaply in advance the proportioning valve C purging in stream to be demarcated in advance, thereby the gas flow purging in gas circuit is controlled in open loop, and concrete steps are as follows:
(1) build proportioning valve characteristic calibrating platform, measure current environmental temperature, according to the requirement of calibration scale, first stablize control ratio valve C two ends air pressure, then, resize ratio valve coil electric current, makes the gas flow of passing ratio valve C reach the requirement in calibration scale;
(2) measurement result is write to calibration scale, as the characteristic that purges proportioning valve C in gas circuit, the pre-demarcation of completed percentage valve C, when gas chromatograph is worked, first, according to the purge stream value of proportioning valve C two ends gaseous tension and user's setting, from calibration scale, by searching with interpolation, obtain the proportioning valve coil current size needing, then, according to current environment temperature correcting current value, and export to proportioning valve C.
As further scheme of the present invention, described proportioning valve characteristic calibrating platform comprises main frame, forefront pressure controller, rear end pressure controller and gas flow sensor and the temperature sensor that contains calibrating procedure; Described forefront pressure controller, rear end pressure controller, gas flow sensor and temperature sensor are all connected with main frame, pre-timing signal, forefront pressure controller and rear end pressure controller access respectively inlet end and the outlet side of proportioning valve C, and gas flow sensor is connected on pressure controlled outlet side, rear end.
In order to guarantee the purge flow rate control accuracy of gas chromatograph in long-term use procedure, gas parameter calibration scale that can regular calibration proportioning valve C, described bearing calibration is interior correction or outer any one that proofread and correct, described interior correction, its concrete steps are as follows:
Interior correction utilizes the carrier gas that is arranged in gas chromatographic device gas circuit to flow into the flow sensor between gas circuit and injection port, after gas chromatograph uses a period of time, with plug, block the injection port of gas chromatograph, and close the proportioning valve B of shunting in gas circuit, now by purging the carrier gas flux of gas circuit, can measure by the flow sensor at carrier gas inlet place, by actual gas flow and proportioning valve C pressure at two ends, calibration scale be proofreaied and correct; If the dimensional parameters of known gas chromatographic column, also can be without plug, by column cap, press and calculate post flow, the carrier gas that flow sensor measures flows into total flow and deducts the gas flow that post flow is purging stream, by actual gas flow and proportioning valve C pressure at two ends, calibration scale is proofreaied and correct; Interior correction does not need external equipment, can regularly automatically be carried out by gas chromatograph.
Described outer correction, refers to and is purging the external flow sensor of gas circuit, and presses by adjusting column cap, and whole calibration scale is carried out more accurately and comprehensively proofreading and correct; External flow sensor precision is higher, and can adjust column cap compacting and now more fully proofread and correct, but needs extra calibration equipment and operation, comparatively complicated.
Beneficial effect
First the present invention demarcates the characteristic that purges the proportioning valve of using in stream, then in purging stream, by the purge gas flow of proportioning valve pressure at two ends and setting, calculate required proportioning valve coil current, after proofreading and correct with Current Temperatures, electric current output by circuit board drives proportioning valve, purge flow rate is controlled in open loop, guaranteeing under the prerequisite of system applies scope and enough accuracy, by reduced a pressure transducer and a vapour lock in purging gas circuit, effectively reduce the cost of whole air-channel system.
Accompanying drawing explanation
Fig. 1 is the hardware platform fundamental diagram that proportioning valve characteristic is demarcated;
Fig. 2 is structured flowchart of the present invention;
Fig. 3 is the interior correcting structure block diagram of proportioning valve characteristic;
Fig. 4 is the outer correcting structure block diagram of proportioning valve characteristic.
Embodiment
Below in conjunction with the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.
Embodiment 1
As shown in Figure 1, the characteristic of proportioning valve C4-2 is demarcated: first determine calibration scale, calibration scale purges pressure and the flow range of gas circuit while wanting the work of coating gas chromatography, calibrating procedure requires to send order to front pressure controller and the rear pressure controller at proportioning valve C4-2 two ends according to calibration scale, the pressure controller at forward and backward two ends is stablized gaseous tension to be controlled at designated value, and temperature sensor is read environment temperature and sent into main frame; By gas flow sensor, read the gas flow that flows through proportioning valve, calibrating procedure is by main frame resize ratio valve coil size of current, make the gas flow of proportioning valve C4-2 reach the requirement of calibration scale, finally by the purging stream 4 in the air-channel system of the proportioning valve C4-2 access gas chromatograph of demarcating through characteristic.
As shown in Figure 2, the air-channel system of gas chromatograph, comprises purging stream 4 and shunting gas circuit that carrier gas that sample for injection port 1 has been gasified is pushed into gas chromatographic column 2 flows into gas circuit, connects with injection port 1, described carrier gas flows between gas circuit and injection port 1 proportioning valve A3 and flow sensor 5 is installed, in described shunting gas circuit, be provided with one and be used for the proportioning valve B6 to setting value by column cap pressure-controlled, proportioning valve B6 rear end is directly connected in atmosphere, the pressure transducer 4-1 that a column cap that is used for measuring injection port is pressed is installed in described purging stream 4, after pressure transducer 4-1, be connected with a proportioning valve C4-2 who is used for controlling purge gas flow, proportioning valve C4-2 rear end is directly connected in atmosphere, purge in stream 4 the gas proportioning valve C4-2 that flows through after pressure transducer 4-1, finally enter into atmosphere, by barometric pressure sensor, can measure current atmospheric pressure value, compared with traditional gas chromatograph, purge gas circuit, a pressure transducer and a vapour lock have been reduced, effectively reduce the hardware cost of gas flow path.
During gas chromatograph work, temperature sensor measurement goes out current environmental temperature, the pressure at two ends purging in stream 4 measures by pressure transducer 4-1, the size of purge flow rate is set by the user, inquiry calibration scale interpolation can obtain the coil current of needed proportioning valve C4-2, thereby realized, to purging the open loop of gas circuit 4 flows, control.
As shown in Figure 3, carrying out the interior timing of proportioning valve, proportioning valve C4-2 in shut-down purge stream 4, and chromatographic column 2 joints are blocked with plug, now all carrier gas fluxes by flow sensor 5 all flow out by the proportioning valve C4-2 purging in gas circuit 4, use temperature sensor measurement environment temperature, proportioning valve C4-2 pressure at two ends now, by flow and environment temperature, be actual measured value, with the value comparison in calibration scale, can obtain the correction coefficient of calibration scale, thereby calibration scale is effectively proofreaied and correct.
If the dimension information of known chromatographic column 2, also can not block chromatographic column joint, the now carrier gas inflow by flow sensor 5 equals to purge the post flow that gas circuit 4 flows add chromatographic column 2; The post flow of chromatographic column 2 can be pressed by column cap, chromatographic column 2 sizes and fire box temperature calculate, thereby can calculate the gas flow of passing ratio valve C4-2, compare with calibration scale, obtain correction coefficient, can effectively proofread and correct calibration scale, this method need not be carried out any modification to the gas circuit structure of gas chromatograph, can regularly in the gap of gas chromatograph operation, automatically proofread and correct.
As shown in Figure 4, carry out the outer timing of proportioning valve, in purging stream 4, access an external flowmeter, measure purge stream value, adjust proportioning valve A3 and proportioning valve B6 that carrier gas flows into gas circuit and shunting gas circuit, make column cap pressure and purge flow rate reach the value in calibration scale, whole calibration scale is carried out more comprehensively and proofreaied and correct accurately.
To those skilled in the art, obviously the invention is not restricted to the details of above-mentioned one exemplary embodiment, and in the situation that not deviating from spirit of the present invention or essential characteristic, can realize the present invention with other concrete form.Therefore, no matter from which point, all should regard embodiment as exemplary, and be nonrestrictive, scope of the present invention is limited by claims rather than above-mentioned explanation, is therefore intended to include in the present invention dropping on the implication that is equal to important document of claim and all changes in scope.
In addition, be to be understood that, although this instructions is described according to embodiment, but not each embodiment only comprises an independently technical scheme, this narrating mode of instructions is only for clarity sake, those skilled in the art should make instructions as a whole, and the technical scheme in each embodiment also can, through appropriately combined, form other embodiments that it will be appreciated by those skilled in the art that.
Claims (3)
1. an air-channel system for gas chromatograph cheaply, comprises purging stream and shunting gas circuit that carrier gas that sample for injection port has been gasified is pushed into gas chromatographic column flows into gas circuit, connects with injection port; Described carrier gas flows between gas circuit and injection port proportioning valve A and flow sensor is installed; In described shunting gas circuit, be provided with one and be used for the proportioning valve B to setting value by column cap pressure-controlled, proportioning valve B rear end is directly connected in atmosphere; It is characterized in that, the pressure transducer that a column cap that is used for measuring injection port is pressed is installed in described purging stream, be connected with a proportioning valve C who is used for controlling purge gas flow after pressure transducer, proportioning valve C rear end is directly connected in atmosphere.
2. an implementation for the air-channel system of the gas chromatograph cheaply as described in claim 1 any one, is characterized in that, in advance the proportioning valve C purging in stream is demarcated in advance, and concrete steps are as follows:
(1) build proportioning valve characteristic calibrating platform, measure current environmental temperature, according to the requirement of calibration scale, first stablize control ratio valve C two ends air pressure, then, resize ratio valve coil electric current, makes the gas flow of passing ratio valve C reach the requirement in calibration scale;
(2) measurement result is write to calibration scale, as the characteristic that purges proportioning valve C in gas circuit, proportioning valve C has demarcated in advance, when gas chromatograph is worked, first, according to the purge stream value of proportioning valve C two ends gaseous tension and user's setting, from calibration scale, by searching with interpolation, obtain the proportioning valve coil current size needing, then, according to current environment temperature correcting current value, and export to proportioning valve C.
3. the implementation of the air-channel system of gas chromatograph cheaply according to claim 2, it is characterized in that, described proportioning valve characteristic calibrating platform comprises main frame, forefront pressure controller, rear end pressure controller and gas flow sensor and the temperature sensor that contains calibrating procedure; Described forefront pressure controller, rear end pressure controller, gas flow sensor and temperature sensor are all connected with main frame, pre-timing signal, forefront pressure controller and rear end pressure controller access respectively inlet end and the outlet side of proportioning valve C, and gas flow sensor is connected on pressure controlled outlet side, rear end.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410339544.0A CN104142377B (en) | 2014-07-17 | 2014-07-17 | A kind of air-channel system of gas chromatograph of low cost |
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| CN201410339544.0A CN104142377B (en) | 2014-07-17 | 2014-07-17 | A kind of air-channel system of gas chromatograph of low cost |
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| CN104142377A true CN104142377A (en) | 2014-11-12 |
| CN104142377B CN104142377B (en) | 2016-03-23 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105675764A (en) * | 2016-03-17 | 2016-06-15 | 成都创源油气技术开发有限公司 | Gas chromatograph for monitoring blocking condition |
| CN107561200A (en) * | 2017-10-13 | 2018-01-09 | 江苏天瑞仪器股份有限公司 | A kind of pressure flow electronic control system for injection port of chromatograph |
| CN113406881A (en) * | 2021-04-12 | 2021-09-17 | 北京北方华创微电子装备有限公司 | Semiconductor heat treatment equipment and control method of oxygen content in loading and unloading chamber thereof |
| CN117428302A (en) * | 2023-12-20 | 2024-01-23 | 苏芯物联技术(南京)有限公司 | Intelligent dynamic control method and system for air supply flow rate of welded pipeline |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| CN113406881A (en) * | 2021-04-12 | 2021-09-17 | 北京北方华创微电子装备有限公司 | Semiconductor heat treatment equipment and control method of oxygen content in loading and unloading chamber thereof |
| CN113406881B (en) * | 2021-04-12 | 2023-09-08 | 北京北方华创微电子装备有限公司 | Semiconductor heat treatment equipment and control method for oxygen content in loading and unloading chamber thereof |
| CN117428302A (en) * | 2023-12-20 | 2024-01-23 | 苏芯物联技术(南京)有限公司 | Intelligent dynamic control method and system for air supply flow rate of welded pipeline |
| CN117428302B (en) * | 2023-12-20 | 2024-02-20 | 苏芯物联技术(南京)有限公司 | Intelligent dynamic control method and system for air supply flow rate of welded pipeline |
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| CN104142377B (en) | 2016-03-23 |
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Effective date of registration: 20181212 Address after: 215000 No. 18 Suzhou River Road, Songling Town, Wujiang District, Suzhou, Jiangsu Patentee after: SUZHOU ABIES PRECISION INSTRUMENTS CO.,LTD. Address before: Room 3115, Building 4, No. 1368 Xingxian Road, Jiading District, Shanghai, 201815 Patentee before: SHANGHAI ABIES PRECISION INSTRUMENT CO.,LTD. |
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Granted publication date: 20160323 |