GC 



Somphng - 

 Loop 



Standard 

 Gas 



Flow Control 

 Vol ve 



Gas Stream 



Containing 

 Dissolved 

 Goses 



Vent 



i 



Drying 

 Tube 



© — © — CZZJ- 



2-Woy Values 



Flow Control 

 Valve 



a 



A 



Septum Cap 

 For Water 

 Withdrawal 



From 

 Submersible Pump 



fL 



Flow Control 



Valve Helium 

 C*0 Corner Gas 



n. 



Stripper 



B 



Water With 

 Dissolved Gases 

 Rem oved 



FIG. 3 Field instrumental configuration. 



FIG. 4 System in operation. 



was analyzed with a gas chromatograph (Hewlett 

 Packard Model 5700A®) equipped with a Swinnerton 

 stripping chamber (Swinnerton, Linnenbom, and 

 Cheek, 1962). The results are shown in Fig. 5. Both 

 the strip charts and a digital integrator on-line to 

 the gas chromatograph indicated the samples to be 

 identical with respect to dissolved nitrogen and 

 oxygen. Hence the pumping system was indeed 

 supplying water to the stripper with dissolved gas 

 concentrations equal to those in the river itself. 



The next step in the field test was to determine 

 the stripper's efficiency in dissolved gas removal. 

 Published information (Williams and Miller, 1962) 

 regarding operation of the stripper unit indicated 

 that 100% stripping efficiency was found when the 

 flow rate ratio of helium/water was maintained 

 between 10 and 0.5 for flow rates up to 100 cc/min. 



Flow rates used in these tests were approximately 

 8 ml/min of water and 22 ml/min of helium. When 

 the system was operating under these conditions, 

 samples were taken from the output of the stripper 

 (Point B, Fig. 3) and analyzed for residual dissolved 

 gas content with the Hewlett Packard® gas chromato- 

 graph previously described. Generally, no peaks 

 were detectable on the strip chart. In a few cases, 

 an extremely small peak was observed but was too 

 small to be detected by the digital integrator. These 

 results indicate that the stripper was quantitatively 

 removing dissolved gas from the continuous water 

 sample and transferring this gas to the helium 

 carrier stream. 



The final phase of the field test was to deter- 

 mine whether a detector could sense the amount 

 of dissolved gases in the carrier stream and from 

 this accurately quantitate the dissolved gas level 

 in the river. The majority of the experimental diffi- 

 culties were encountered in this phase. Since time 

 did not permit fabrication of a detector specific for 

 this task, a portable gas chromatograph (Analytical 



186 



Injec 



River Sample 



Sample Taken From 

 Point A On Pump 

 Line 



FIG. S Chromatogram of dissolved gases in river water and 

 continuously pumped sample. 



704 Jenkins 



