ASTM D7153 Test Method for Freezing Point of Aviation Fuels (Automatic Laser Method)
6. Apparatus
6.1 Automatic Apparatus - This apparatus consists of a microprocessor-controlled test cell that is capable of cooling and heating the specimen, dual optical detectors to monitor the appearance and disappearance of crystals and opacity, and recording the temperature of the specimen. A detailed description of the apparatus is provided in Annex A1.
6.2 The apparatus shall be equipped with a specimen chamber, optical detectors, laser light source, digital display, cooling and heating systems, and a specimen temperature measuring device.
6.3 The temperature measuring device in the specimen chamber shall be capable of measuring the temperature of the specimen from -80 °C to +20 °C at a resolution of 0.1 °C and accuracy of 0.1 °C.
6.4 The apparatus shall be capable of cooling the specimen at a rate of 10 °C/min +/- 5 °C/min, heating the specimen at rates of 3 °C/min +/- 0.5 °C/min and 12 °C/min +/- 1 °C/min over the temperature range of -80 °C to +20 °C.
NOTE 1 - The apparatus described is covered by a patent. If you are aware of an alternative(s) to the patented item, please attach to your ballot return a description of the alternatives. All suggestions will be considered by the committee.
NOTE 2 - The software version used in this apparatus is version V 5.3.
6.5 Standard Syringe, capable of injecting approximately 10 mL +/- 2 mL of the specimen, with a tip or an adapter tip that will fit the inlet of the test cell. A disposable 10 mL syringe with a Luer type cone connection has been found suitable.
6.6 Waste Receiving Container, capable of collecting the overflow when the specimen is injected into the test cell. A 400 mL standard glass beaker has been found suitable.
7. Sampling
7.1 Obtain a sample in accordance with Practice D4057 or D4177.
7.2 At least 30 mL of sample is required for each test.
8. Preparation of Apparatus
8.1 Install the apparatus for operation in accordance with the manufacturer's instructions.
8.2 Turn on the main power switch of the analyzer.
9. Calibration and Standardization
9.1 Ensure that all of the manufacturer's instructions for calibration of the mechanical and electronic systems and operation of the apparatus are followed.
9.2 To verify the performance of the apparatus, an aviation turbine fuel sample for which extensive data has been obtained by Test Method D2386 may be used. Samples such as those used in the ASTM interlaboratory cross–check program would meet this criterion. Such verification materials can also be prepared from intra-company cross–checks.
9.3 At intervals of not more than 12 months, check the temperature measuring system against a temperature measuring device that has a current calibration certificate.
9.4 Verify the correct functioning of the apparatus in accordance with the manufacturer's instructions using a verification liquid (9.2) when first installed and thereafter at intervals not exceeding one month.
