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Once the water is no longer freely flowing out of the sample chamber it is time to open the pressurized transfer head assembly and force the water out. In the past an 'empty' nitrogen bottle was used at 20psi for this purpose as to not contaminate the sample with oxygen. As the sample chamber get close to empty lift the pressurized end up to ensure the most water come out before the nitrogen begins to come out. Once this happens the sampling is complete and hopefully there was close to 600mL of water obtained.
Cleaning/Maintenance
1. Rinse with DI water
Keep tool set up just as it was being sampled from with both transfer head assemblies attached. the goal is to rinse anything that would come in contact with the sample water as it is being extracted. Place the tool in a secure vertical position. Fill up a carboy with at least 1.8L of DI water and run a line from the carboy into the lower transfer head assembly. From the upper assembly and sample manifold run a hose into a (chamber*) that is then connected to a vacuum pump. If set up correctly(fig. 14) once the pump is turned on it will suck the water through the tool effectively rinsing it three times. Remember not to have the openings of the (chanber*) directly opposite each other as the water will spray and some may get into the pump.
