ASTM D3305 Standard Practice for Sampling Small Gas Volume in a Transformer
4. Apparatus
4.1 Syringe, gastight, 5-mL, with luer loc termination.
4.2 Stopcock, three-way, plastic.
4.3 Length of PTFE Tubing, 1/8 in. inside diameter.
5. Procedure
5.1 Connect the plastic stopcock to the plastic tubing. Connect the other end of tubing to a suitable valved entrance to the transformer gas space or gas-collector relay.
5.2 Open the valve and stopcock so gas space gas can flush air from valve, tubing, and stopcock. (The stopcock handle points to the closed port, leaving the other two ports in open communication.)
5.3 Connect syringe to the stopcock.
5.4 Turn the stopcock handle to allow gas from the gas space to enter the syringe, taking care that gas pressure does not eject the plunger completely.
5.5 Turn the stopcock so gas can be expelled from the syringe through the exhaust port of stopcock by pushing plunger home.
5.6 Open the stopcock to connect gas space to syringe and fill syringe. Close the stopcock by turning handle toward the syringe.
5.7 Close the valve on the gas space.
5.8 Remove the plastic tubing from the valve and stopcock, leaving the stopcock on the syringe.
5.9 Label the sample, package carefully, and transport to laboratory for analysis.
6. Keywords
6.1 gas; sampling gas; transformer
