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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
30. Procedure30.1 Headspace Vial Volume Determination - Because of the importance of the VG/VL phase ratio factor in the concentration calculation (Eq 17), the following vial volume determination procedure must be applied to detect any variation from batch to batch and manufacturer to manufacturer.30.1.1 ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
29. Chemicals29.1 Argon, Air, and Hydrogen Cylinders, 99.999 % pure. Argon is used to overpressurize the headspace and to carry the substances contained in the injection loop through the stationary phase to the detectors.29.2 Three Gas Mixtures, prepared with a precision of about 0.5 % used to establish ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
28. Apparatus28.1 Headspace Sampler, equipped with an injection loop and a transfer line connected directly to the first column of the gas chromatograph. The sampler must be capable of equilibrating the species of interest in a specific time. The required equilibration time can be minimized by mixing ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
METHOD C - HEADSPACE SAMPLING27. Method C - Headspace sampling27.1 Method C consists of bringing an oil sample in contact with a gas phase (headspace) in a closed vessel purged with argon. As a result, a portion of a gas (H2, O2, N2, CH4, CO, CO2, C2H2, C2H4, C2H6, or C3H8) of concentration C (O/L) dissolved ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
26. Precision and Bias26.1 The precision, bias and lower limit of detection of Method B have been evaluated by a statistical examination of the results of an inter-laboratory test of mineral oil test specimens. A lower limit of repetition is defined here as an aid in the testing of transformers in factories.26.2 ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
23. Procedure for Direct Injection23.1 Prepare the gas chromatograph as outlined by the manufacturer.23.2 Prepare the sample for injection by first dissolving any gas bubble present into the volume of oil by compressing the plunger into the barrel of the syringe and agitating the gas by tipping the syringe ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
21. Calibration (Gases)21.1 Prepare the gas chromatograph for use as directed by the manufacturer, and establish a set of operating conditions capable of separating the indicated component gases.21.2 Inject a pre-established volume of the reference standard (low concentration) gas mixture into the chromatograph ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
20. Reagent and Materials20.1 Suitable Chromatography Columns - Several combinations have been found to be suitable including molecular sieve, Porapak Q, Porapak N, diisodecyl phthalateA, Silica Gel J, Chromosorb 102, Carbosieve B, and Sperocarb. Molecular sieve is used to separate H2, O2, N2, CH4, and ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
METHOD B - STRIPPER COLUMN EXTRACTION18. Method B - Stripper Column Extraction18.1 Dissolved gases are extracted from a sample of oil by sparging the oil with the carrier gas on a stripper column containing a high surface area bead. The gases are then flushed from the stripper column into a gas chromatograph ...
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ASTM D3612 for insulating oil dissolved gas analysis by gas chromatography
17. Precision and Bias17.1 The precision, bias and lower limit of detection of Method A have been evaluated by a statistical examination of the results of an inter-laboratory test of mineral oil test specimens.12 A lower limit of repetition is defined here as an aid in the testing of transformers in ...
