ASTM D3613 for Sampling Insulating Liquids for Gas Analysis and Water Analysis
ASTM D3613 Standard Practice for Sampling Insulating Liquids for Gas Analysis and Determination of Water Content
4. Apparatus
4.1 Sample Containers, may be glass syringes, stainless steel cylinders, or metal cans having flexible sides (to allow for volume changes caused by expansion or contraction of the oil).
4.1.1 Glass Syringes, of a suitable size terminated with a luer lock fitting to which is attached a three-way stopcock, should be used. Syringes having precision ground barrels and pistons are preferred.
4.1.2 Stainless Steel Sampling Cylinders, equipped with valves on each end may be used for sampling. These cylinders have the disadvantage of not allowing visual inspection of the interior of the cylinder.
4.1.3 Flexible-Sided Metal Cans, having screw caps may also be used.
4.2 Flush Oil Container - of at least 3.8 L (1 gal) to contain the required flush liquid during preparation and sampling.
4.3 Clear Poly (Vinyl-Chloride) Tubing - or any tubing that meets the requirements of this practice that is oil resistant. Size shall be selected to guarantee a gas and liquid tight fit at the sampling port and on the syringe or steel cap. To minimize waste and potential spills a length of 60 cm (24 in.) is suggested and has proven to be acceptable for manipulation of the collection container while attached to the sample port.
5. Cleaning of Apparatus
5.1 A proven method for cleaning sample containers and accessories is the use of a cleaning agent that completely dissolves liquid residue, and shall then be subjected to soap and water cleaning and water rinse followed by a distilled water rinse. See Test Methods D923 for further details about general cleaning requirements.
5.2 Allow the container to drain for 10 min, and dry in a forced-draft oven at 110°C for not less than 1 h. When the drying period has expired, syringe pistons shall be placed in their barrels, valves closed; stainless steel cylinder valves should be closed; or cans sealed with their screw cap. It is desirable that stainless steel cylinders be evacuated and sealed after cleaning.
5.3 The poly(vinyl chloride) tubing should be replaced with new tubing each time a sample port is used. Cleaning the tubing should be considered impractical.
5.4 Alternate Stainless Steel Cylinder Cleaning Method:
5.4.1 Rinse the cylinder with a suitable volatile solvent.
5.4.2 Allow the cylinder to drain for 10 min with both valves full open, placing the cylinders in a vertical position.
5.4.3 Dry the cylinder by passing dry air through the cylinder until the cylinder is dry. This should involve a volume of air equivalent to at least 55 changes of the cylinder volume during the 15 min period of drying. The air may be dried by passing the air through two drying towers in series, each tower is at least 9 cm diameter and 28 cm in height. Towers filled with 6-16 mesh indicating Silica Gel have been found acceptable.
5.4.4 After 15 min close the cylinder valves and prepare the cylinders for use.
