GASMET傅立叶红外仪器说明书

GASMET TM DX-4010 FT-IR Gas AnalyzerON-SITE SeriesInstruction & OperatingManual2002-03-15WARRANTY STATEMENTThis warranty applies to the GASMET TM brand name products sold with this warranty statement. This warranty is applicable in all countries and may be enforced in any country where Temet Instruments Oy or its authorised service providers offer warranty service subject to the terms and conditions set forth in this warranty statement.Temet Instruments Oy shall not be liable for technical or editorial errors or omissions contained herein. The information in this document is provided “as is” without warranty of any kind and is subject to change without notice. Should you find any error, we would appreciate if you notified us.Temet Instruments Oy quarantees that all products manufactured and sold by it are free of defects in materials and workmanship under normal use during the warranty period.Temet Instruments’ products are manufactured using new materials or new and used materials equivalent to new in performance and reliability. Spare parts may be new or equivalent to new.Temet Instruments Oy agrees to either replace or repair free of charge (Ex Works Helsinki, Incoterms 2000), any such defective product or part, that is returned to its repair facility within one (1) year of the delivery date. All parts or products removed under this warranty become the property of Temet Instruments Oy. The replacement product or part takes on the warranty status of the removed product or part.The warranty does not extend to any product from which the serial number has been removed or that has been damaged or rendered defective (a) as a result of accident, misuse, abuse, normal wear of components or other external causes; (b) by operation outside the usage parameters stated in the user documentation that is provided with the product; (c) by the use of parts not manufactured by Temet Instruments Oy; or (d) by modification or service by anyone other than Temet Instruments Oy.Temet Instruments Oy is not liable for any damages caused by the product or the failure of the product to perform, including any loss of profits or savings, incidental damages, or consequential damages.GASMET TM and CALCMET TM are trademarks of Temet Instruments OyCONTENTS1INTRODUCTION (8)2PRINCIPLE OF MEASUREMENT (8)2.1P RINCIPLES OF I NFRARED S PECTROSCOPY (9)2.2C OMPONENTS OF A F OURIER T RANSFORM I NFRARED S PECTROMETER (11)2.3Q UANTITATIVE A NALYSIS OF FT-IR S PECTRA (13)2.4M ULTICOMPONENT A NALYSIS (14)2.5R ESOLUTION OF FT-IR A NALYSIS (15)2.6D ESCRIPTION OF THE GASMET TM DX-4010 (16)2.6.1 Applications of the GASMET TM DX-4010 Analyzer (16)2.6.2 The GASMET TM DX-4010 Analyzer Performance (17)2.6.3 Structure of the GASMET TM DX-4010 Analyzer (17)2.7GASMET TM DX-4010 T ECHNICAL D ATA (18)2.7.1 General Parameters (18)2.7.2 Spectrometer (18)2.7.3 Sample Cell (18)2.7.4 Measuring parameters (19)2.7.5 Electrical connectors (19)2.7.6 Gas Inlet and Outlet Conditions (19)2.7.7 Computer and Electronics (19)2.7.8 Enclosure (19)3INSTALLATION (21)3.1S UPPLY S CHEDULE (21)3.1.1 Package (21)3.1.2 Contents of the GASMET TM Package (21)3.1.3 Settings (21)3.2A MBIENT C ONDITIONS (22)3.2.1 Storing and Transporting the GASMET TM (22)3.2.2 Installation location (22)3.2.3 Explosion Protection (22)3.3S AMPLE G AS S UPPLY (23)3.4G AS C ONNECTORS (24)3.5O N-B OARD S AMPLE P UMP (25)3.6P OWER C ONNECTION (25)3.6.1 Power Supply (25)3.6.2 Fuses (25)3.7S IGNAL C ONNECTIONS (26)3.7.1 Optional Analog Output Signals (26)3.7.2 RS232C-Interface (26)3.7.3 Sample sequencing control (26)3.7.3.1Valve Dry Contact (27)3.7.3.2Pump Dry Contact (27)4MAINTENANCE (28)4.1S AFETY P RECAUTIONS (28)4.2M AINTENANCE P LAN (28)4.3V ISUAL I NSPECTION (29)4.4S AMPLE C ELL I NSPECTION (29)4.5R EPLACEMENT OF O PTOELECTRONIC C OMPONENTS (29)5START-UP (30)5.1C ONNECTIONS (30)5.2I NSTALLING THE SOFTWARE (30)5.2.1 Installing Calibration Files (30)5.3S WITCHING THE ANALYZER’S POWER ON (31)5.4O PERATION (31)5.4.1 Using the CALCMET Software (31)5.4.2 Setting the Measuring Times (34)5.4.3 Zero Calibration (34)5.4.4 Measuring the Sample Spectrum (35)5.4.4.1Single Measurement (35)5.4.4.2Continuous Measurement (36)5.4.5 Checking the Hardware (37)5.4.6 Analyzing the Sample Spectrum (37)5.5S AMPLE CALCMET SESSION (37)5.5.1 Step 1: Select the Components that will be analyzed (37)5.5.2 Step 2: Measure Background (37)5.5.3 Step 3: Measure and Analyze the Sample (38)5.5.4 Step 4: Verify the Results (38)6ANALYZER INSPECTION (39)6.1GASMET FT-IR G AS A NALYZER I NSPECTION S HEET (40)FIGURESFigure 1 Normal modes of vibration of carbon dioxide CO2 (9)Figure 2 An absorbance spectrum of Sulfur dioxide SO2 (11)Figure 3 Basic components of a FT-IR spectrometer (11)Figure 4 Michelson interferometer (12)Figure 5 A typical intereferogram (12)Figure 6 An example of spectra for multicomponent analysis (15)Figure 7 A basic structure of GASMET TM DX-4010 analyzer (17)Figure 8 Dimensionnal Drawing of the Analyzer Enclosure (20)Figure 9 Gas Connectors of the GASMET DX-4010 (24)Figure 10 Flow schematics of the on-board sample pump package (25)Figure 11 GASMET TM DX-4010 Connector unit (26)Figure 11 Welcome to Calcmet dialog (32)Figure 12 A typical background spectrum (35)TABLESTable 1 GASMET fuses. Physical size of each fuse is 5*20 mm (26)Table 2 Maintenance plan (29)Table 3 Welcome to Calcmet system parameters (33)Table 4 Commands for setting measuring times (34)Table 5 Zero Calibration measurement commands (34)Table 6 Single measurement commands (36)Table 7 Continuous measurement commands (36)Table 8 Commands for checking hardware status (37)PREFACEThank you for choosing GASMET TM, the state-of-the-art FT-IR gas analyzer manufactured by Temet Instruments. The GASMET TM is a high-tech product made of high quality components.Temet Instruments’ substantial investment in R&D is targeted at innovative, customer-driven solutions. Working closely with customers and global distribution network, the company offers extensive technical applications support services. Along with high reliability, Temet products offer easy operation and consistent and accurate results, together with competitive pricing.To develop the powerful technology of FT-IR has required uncompromising commitment and expertise in several fields of high technology. As a result, Temet products are not only superior in performance, but simple to operate and maintain. Temet Instruments’ continuing philosophy is to provide reliable measurements in a variety of industrial applications now and in the future. Whatever your applications are, we hope you will find the GASMET TM gas analyzer fast, accurate, reliable, and easy to use.1 INTRODUCTIONThis instructions manual provides information of the GASMET TM DX-SERIES Fourier Transform Infrared (FT-IR) Gas Analyzer. Please read this manual carefully prior to using the analyzer. Improper use of the analyzer may damage the equipment.Chapter 2, "Error! Not a valid bookmark self-reference.", discusses theoretical aspects of infrared spectroscopy. These fundamentals help understand the physical principles the GASMET TM system is based on. “Description of the Gas Analyzer” provides information about the GASMET TM DX-SERIES hardware and technical specifications.Chapter 3, “Installation”, provides information of installing the GASMET TM DX-SERIES Gas Analyzer. Use this paragraph to check the contents of the GASMET TM package and to get the GASMET TM from storage into operational condition.Chapter 4, “Maintenance”, describes the maintenance operations that may be necessary in the long run.Chapter 5, "Start-Up", provides some basic information of the operation of the GASMET TM DX-SERIES. This chapter is recommended to read, before any operation.Chapter 6, “Error! Reference source not found.”, describes what shloud be done when the analyzer is used first time. This chapter includes inspection sheet, what should be filled within 30 days from the date of delivery, in order that the warranty is in full valid.To learn how to operate the GASMET TM analyzer with the CALCMET TM controlling and analyzing software, refer to the CALCMET User’s Guide.This instructions manual is copyrighted 2001 by Temet Instruments. All rights reserved. No part of this manual may be reproduced in whole or in part in any form without the prior permission of Temet Instruments Oy.2 PRINCIPLE OF MEASUREMENT2.1 Principles of Infrared SpectroscopyWhen infrared radiation is passed through a sample of gaseous molecules, it can be observed that certain wavelengths of the infrared radiation are not transmitted through the gas very well. That is, the gas absorbs some specific wavelengths of the infrared radiation. What happens is that the infrared radiation interacts with the gas molecules. The gas molecules get energy from the infrared radiation and start to vibrate or rotate with increasing amplitude. This energy transfer from the infrared radiation to the gas molecules can be seen as decreased intensity of some wavelengths of the transmitted infrared radiation. If the infrared source sends a broad band of wavelengths of infrared radiation through the sample, some of the wavelengths will be partly absorbed by the gas sample.Figure 1shows how a gas molecule may behave when it interacts with infrared radiation. All different vibrations, rotations, and their combinations result in absorption of specific wavelengthsof the infrared radiation.CONTRACTSTRETCHSTRETCHSTRETCH C OO C OO COOOO υ1υ2υ34Figure 1Normal modes of vibration of carbon dioxide CO 2.An absorption spectrum shows graphically to what extent the different wavelengths of the infrared radiation are absorbed by the sample gas. The spectrum shows the transmission of the infrared radiation through the gas as a function of wavelength. For each wavelength, thetransmittance T is the intensity of the infrared radiation that has passed through the sample gas, divided by the intensity of the infrared radiation that has entered the sample gas. When there is no absorption, the value of transmittance T is 1 (or 100 %), which indicates that 100 % of the infrared radiation at that wavelength goes through the sample gas. If the intensity of the radiation entering the sample is I 0 and the intensity of the radiation that has passed through the sample is I, the transmittance T can be expressed as:T I I =/0T transmittanceI =intensity entering the sample I =intensity that has passed through the sample0=Besides using transmittance T, the absorption of the infrared radiation can be presented using the absorbance scale. Absorbance A is given by the logarithm of the transmittance reciprocal: A T =log 10(/)1A absorbance T transmittance ==The advantage of using the absorbance scale is that the value of absorbance is directlyproportional to the thickness of the sample gas (absorption path length), and the concentration of the sample gas.The infrared absorption spectrum is unique to all different gas molecules. It is possible to identify any gas component from the spectrum of the sample. An example of infrared absorbance spectrum is shown in Figure 2.Figure 2 An absorbance spectrum of Sulfur dioxide SO2.2.2 Components of a Fourier Transform Infrared SpectrometerThere are some basic parts that are typical for all FT-IR spectrometers. First of all, there is an infrared source that emits a broad band of different wavelengths of infrared radiation. The infrared radiation goes through an interferometer that modulates the infrared radiation. The interferometer performs an optical inverse Fourier transform on the infrared radiation entering the interferometer. The modulated infrared beam passes through the gas sample. Finally, the intensity of the infrared beam is detected by a detector. The detected signal is digitized and Fourier transformed by the computer to get the IR-spectrum of the sample gas.Figure 3 Basic components of a FT-IR spectrometer.The unique part of a FT-IR spectrometer is the interferometer. A Michelson type plane mirror interferometer is displayed in Figure 4. Infrared radiation from the source is collected and collimated before it strikes the beamsplitter. The beamsplitter ideally transmits one half of the radiation, and reflects the other half. Both transmitted and reflected beams strike mirrors, which reflect the two beams back to the beamsplitter. Thus, one half of the infrared radiation that finallythen back to the beamsplitter. The other half of the infrared radiation going to the sample has first gone through the beamsplitter and then reflected from the fixed mirror back to the beamsplitter. When these two optical paths are reunited, interference occurs at the beamsplitter because of the optical path difference caused by the scanning of the moving mirror.Radiation to the sample gas and detector Moving mirrorFixed mirrorFigure 4 Michelson interferometer.The optical path length difference between the two optical paths of a Michelson interferometer is two times the displacement of the moving mirror. The interference signal measured by the detector as a function of the optical path length difference is called the interferogram. A typical interferogram produced by the interferometer is shown in Figure 5. The graph shows the intensity of the infrared radiation as a function of the displacement of the moving mirror. At the peak position, the optical path length is exactly the same for the radiation that comes from the moving mirror as it is for the radiation that comes from the fixed mirror.Figure 5 A typical intereferogram.The spectrum can be computed from the interferogram by performing a Fourier transform. The Fourier transform is performed by the same computer that ultimately performs the quantitative analysis of the spectrum.2.3 Quantitative Analysis of FT-IR SpectraThe basic law for spectroscopic quantitative analysis is Beer's law. Beer's law shows how the concentration of the sample gas is related to the measured absorbance of the sample spectrum. Beer's law is commonly expressed as:log(/)log(/)I I T A abc 01===I =intensity entering the sampleI =intensity that has passedthrough the sampleA absorbance T transmittancea a()absorptivityb optical path lengthc =sample concentration0=====vThe absorptivity a is a constant that characterizes the capacity of the molecule to absorb infrared radiation. The value of a varies from one molecule to another and one wavelength to another, but is constant for a given molecule at a given wavelength. The quantity b is the optical path length, that is, the distance the infrared radiation beam traverses in the gas sample. The quantity cindicates the concentration of the sample gas molecules in the sample. If the optical path length is held constant, Beer's law states that the absorbance is directly proportional to the concentration of the sample gas at a given wavelength. Since Beer's law is additive, absorbance A is equal to the sum of the values of the a , b , and c for each gas component.Two conditions are implied in the derivation of Beer's law. The radiation being measured is monochromatic, and the sample absorptivity does not vary with concentration. If the sample concentration range is wide, the change in the sample environment can cause absorptivitychanges and deviations from Beer's law. For narrow concentration ranges and for low absorbance values a plot of concentration versus absorbance is nearly linear.The changes in the gas pressure may cause broadening in the absorption line shape of the sample gas. The rotational fine structure of gas-phase bands are broadened by collisions between the molecules of the component being measured. All IR-bands are broadened.The changes in the gas temperature may cause 'hot bands' in the spectrum of the sample gas. As the temperature increases, the distribution of the molecules in different energy levels changes. The changes in the temperature cause changes in the absorption line shape of the sample gas. To analyze the concentration of a gas compound, the GASMET TM calculates the number of gas molecules in the sample cell. The number of the gas molecules in the sample cell depends linearly on both the gas pressure and the volume of the sample cell, and reciprocally on the gas temperature:pV nRT =p=pressureV=volumen=number of the gas moleculesT=temperatureR=Ideal gas constantAny changes in sample gas temperature or pressure in the sample cell directly affect on the measured gas compound concentration. In addition, gas pressure or temperature changes may effect the line shape of the measured absorbance spectrum, and thus the accuracy of the analysis results.2.4 Multicomponent AnalysisThe degree of absorption of infrared radiation at each wavelength is quantitatively related to the number of absorbing molecules in the sample gas. Since there is a linear relationship between the absorbance and the number of absorbing molecules, multicomponent quantitative analysis of gas mixtures is feasible.To perform multicomponent analysis we start with the sample spectrum. In addition, we need reference spectra of all the gas components that may exist in the sample, if these components are to be analyzed. A reference spectrum is a spectrum of one single gas component of specific concentration. In multicomponent analysis we try to combine these reference spectra with appropriate multipliers in order to get a spectrum that is as close as possible to the sample spectrum. If we succeed in forming a spectrum similar to the sample spectrum, we get the concentration of each gas component in the sample gas using the multipliers of the reference spectra, provided that we know the concentrations of the reference gases.For example, suppose we have a sample spectrum and reference spectra like those shown in Figure 6. In this case, we know that the sample gas consists of gases Reference 1 and Reference 2. We have the reference spectra available and we know that these reference spectra represent concentrations of 10 ppm and 8 ppm respectively. To find out the concentration of each component in the sample gas, we try to form the measured sample spectrum using a linear combination of the reference spectra. We find out that if we multiply the spectrum Reference 1 by 5 and the spectrum Reference 2 by 2, and combine these two spectra, we get a spectrum that is similar to the sample spectrum. Accordingly, the sample gas contains reference gas 1 at five times the amount in the reference spectrum 1, and reference gas 2 at two times the amount in the reference spectrum 2. The analysis indicates that the sample indeed consists of these two reference gases. The concentration of the reference gas 1 in the sample is found to be 50 ppm, and the concentration of the reference gas 2 in the sample is 16 ppm.increases and makes the analysis less precise.Furthermore, the information content of the measurement is not maximized by using as high a resolution as possible. Scientific research1 has proved that when the resolution is reduced by the some factor 1/k, signal-to-noise-ratio can be increased by a factor of k3/2 in the same registration time. This makes the use of low resolution quite worthwhile. To achieve precise quantitative analysis results, a low resolution measurement should be used provided that the spectral overlap problem can be taken care of.There are two reasons for the increase of the signal-to-noise ratio:• In an FT-IR spectrometer, the length of the measured interferogram determines the resolution. The longer the interferogram, the more data points, and the higher the resolution.In a high resolution study the time required by a single measurement is also high, so that we are able to co-add less measurements in a fixed time, leading to higher noise level. As a result, the longer the measured interferogram is, the lower signal-to-noise-ratio results.• High resolution requires narrow slit or a small aperture to prevent a phenomenon called aperture broadening. Narrow slit, in turn, reduces the signal and thus signal-to-noise-ratio ratio.1 See for example, P Saarinen & J Kauppinen. 1991. Multicomponent Analysis of FT-IR Spectra. Applied Spectroscopy. Volume 45, Number 6. Pages 953 - 963.2.6 Description of the GASMET TM DX-4010GASMET TM ON-SITE SERIES includes portable and transportable multicomponent gas analyzers for demanding applications. The GASMET TM DX-4010 incorporates a Fourier Transform Infrared, FT-IR spectrometer. The analyzer offers versatility and high performance for all users.The GASMET TM DX-4010 in designed for on site measurements. It is an ideal tool to environmental applications. Sample cell absorption path length is 9.6 m and the temperature 50 °C.The GASMET TM DX-4010 incorporates advanced hardware and software to provide a portable high-speed gas analysis system. The GASMET TM DX-4010 brings analytical laboratory performance in non-laboratory conditions. The GASMET TM DX-4010 eliminates the equipment, calibration, and service costs associated with multiple, single component gas analyzers. GASMET TM DX-4010 allows simple calibration using only single component calibration gases, the user can easily configure the analyzer for a new set of compounds.The software of GASMET TM is based on the powerful multicomponent analysis method CALCMET TM. The CALCMET TM analysis method is used to compute the concentrations and error limits of the different components present in the sample gas. The reference spectra needed in the analysis are stored on the fixed disk of computer and are simply loaded from the library when used in the analysis of an unknown sample. CALCMET for Windows software is described in the “CALCMET for Windows Software Manual”2.6.1 Applications of the GASMET TM DX-4010 AnalyzerThe GASMET TM DX-4010 enables identification and quantification of multiple gaseous compounds simultaneously and accurately, with results available in seconds.The GASMET TM DX-4010 is a versatile gas analyzer that can be used in several applications. The GASMET TM DX-4010 is specially designed for:• Environmental emissions monitoring• Quality control• Workplace air monitoring2.6.2 The GASMET TM DX-4010 Analyzer Performance• Lowest detectable concentrations: 0.2-2 ppm (depends on the application).• Accuracy: 2 % of the measurement range (depends on the application)• Precision: 0.01 % of the measurement range (depends on the application)• Diatomic homonuclear gases (i.e. N2, O2, H2, Cl2) and noble gases (i.e. He, Ne, Ar, Kr) do not absorb infrared radiation. They are the only gases that cannot be measured by the GASMET TM2.6.3 Structure of the GASMET TM DX-4010 AnalyzerFigure 7 outlines a complete gas analysis system. The IR source produces broad band IR radiation which is modulated in the interferometer. The interferometer actually performs an optical inverse Fourier transform. The modulated IR radiation passes through the sample cell where sample gas absorbs certain wavelengths of the IR radiation. The detector detects the transmitted IR radiation. The signal is digitized by A/D converter. The computer performs a mathematical Fourier transform on the digitized modulated signal, and a spectrum is obtained. The GASMET TM uses a Fast Fourier Transform to compute the spectrum from the interferogram. The transmittance spectrum is computed as a ratio of the sample spectrum to the background spectrum. The absorbance spectrum is computed from the transmittance spectrum. The GASMET TM uses the CALCMET TM software to compute the concentrations of the components present in the sample gas from the absorbance spectrum.Figure 7 A basic structure of GASMET TM DX-4010 analyzer.The data and signal processing electronics control the operation of the GASMET. An external PC compatible computer controls the GASMETTM DX-4010.A unique part of the GASMET is the Temet Carousel interferometer. The Carousel interferometer is rugged and withstands the demanding environmental conditions of non-laboratory environment. The Carousel interferometer modulates the infrared radiation coming from the infrared source, as discussed previously.The modulated light passes through the temperature controlled sample cell. The gas sample is introduced into the gas cell through standard gas line connectors. The transmitted infrared radiation is finally detected by a thermoelectrically cooled detector.2.7 GASMET TM DX-4010 Technical Data2.7.1 General ParametersMeasurement principle:FT-IR (Fourier Transform Infrared)Performance: Simultaneous analysis of up to 50 gas compuondsResponse time: <120 s, depending on the gas flow and measurements timeOperating temperature: 20 ± 20°C, optimum 15 - 25°C non condensingStorage temperature: -20 - 60°C, non condensingPower supply: 12 VDC or 100-240 VAC / 50 - 60 Hz2.7.2 SpectrometerInterferometer: Temet© Carousel InterferometerResolution: recommended 8 cm-1 or 4 cm-1Scan frequency: 10 spectra/sAperture: 1’’Detector: Thermo-electrically cooled MCT or DTGSIR-source Ceramic, SiC, 1550 K temperatureBeamsplitter: ZnSeWindow material: ZnSeWavenumber range: 700 – 4200 cm-12.7.3 Sample CellStructure: Multi pass, fixed path length 1.2m, 2.5m, 5.0m, or 9.8mMaterial: 100 % Gold coater aluminiumMirrors: fixed, protected gold coatingVolume: 1.07 lConnectors: Swagelok 6 mm or 1/4"Gaskets: Teflon® coated Viton® or Kaltrez® O-ringsTemperature: 50 °C, maximumMaximum sample gas pressure: 2 barsFlow rate 1-5 l/minResponse time: <60 sSample condition: non condensing2.7.4 Measuring parametersZero point calibration: 24 hours calibration with nitrogen (4.0 or higher N2 rekomended)Zero point drift: 2 % of smallest measuring range per zero point calibration interval Sensitivity drift: noneLinear derivation: 2 % of smallest measuring rangeTemperature drift: 2 % of smallest measuring range per 10 °C temperature changePressure influence: 1 % change of measuring value for 1 % sample pressure change2.7.5 Electrical connectorsDigital interface: RS-232 C, 9-pole D-Connectors. CR4000/2000/1000 is connected to anexternal computer via RS-232 C cable. The external computer controls theGASMET.Power connection: Standard plug CEE-22Relay connection: External PCAnalog input/output External PC2.7.6 Gas Inlet and Outlet ConditionsGas temperature: non-condensing, the sample gas temperature should be the same as the samplecell temperatureSample pump: InternalFlow rate: 120-160 l per hourGas filtration: filtration of particulates (2µ) requiredSample gas pressure: ambient2.7.7 Computer and ElectronicsA/D converter: dynamic range 95 dBSignal Processor: 32-bit floating point DSP 120 MFLOPS speedComputer: External, not includedOperating system: Windows 95 or 98Analysis software: CALCMET for windows 95/982.7.8 EnclosureMaterial: AluminumDimensions (mm): 433 ∗ 185 ∗ 425Weight: 16 kgCE label: according to EMI guideline 89/336/ECCE mark indicates compliance with directive 89/336/EEC for electromagnetic Compability. The CE marked GASMET models are certified by the manufacturer as follows:。