mixture from the sampling point was pumped through the intake line into 

 a filtering tube placed inside the collecting tank (Figure 5). The 

 filtering tube (Figure 8) was rectangular in shape, was made from 

 plexiglas, and was of water-tight construction; panel sectionsof the 

 rectangular tube were left open and covered by filters using water- 

 tight seals to attach the filters to the tube. A rubber stoppered 

 hole at the top of the filtering tube permitted entry of the 1/4-inch 

 intake line. A small removable panel at the base of the filtering tube 

 facilitated convenient extraction of the sediment sample. The collection 

 and filtration process employing the use of the plexiglas filtering 

 tube was considered the most satisfactory method and is currently in 

 use at the Beach Erosion Board laboratory. The filtering tube as designed 

 in the test program and illustrated in Figure 8 is simple and economical 

 to construct. Its use simplifies sample collection and facilitates 

 subsequent extraction of sediment which should minimize some of the 

 inherent error of suspended sediment analysis. The sampling tube can 

 further be adapted to several types of filters and thus more readily 

 fit the needs of the user. The entire sampling apparatus is portable 

 and may be quickly set-up for the collection of suspended sediment 

 samples. 



Collection of Fluid-Sediment Mixture. The actual operating pro- 

 cedure for collecting the desired volume of fluid-sediment mixture for 

 subsequent extraction of sediment by any of the above filtration 

 methods was as follows: (1) with the intake valve closed, the vacuum 

 pump motor was started and run for sufficient time to reach a maximum 

 and constant gage reading. This gage reading on a 3-inch vacuum 

 gage remained (fairly) steady at 26.5 inches of mercury during the pump- 

 ing of a sample. (2) while maintaining a constant gage reading, the 

 intake valve was opened for sufficient time to collect the desired 

 volume of the fluid-sediment mixture; this volume was measured in 

 milliliters by a graduate scale attached along the side of the pyrex 

 collecting tank. The sampling time (actual pumping time) needed to 

 collect the volume of flu id- sediment mixture was measured by stop-watch. 



Sediment Drying and Weighing . After collection of the sample in 

 the filtering tube, it was removed by washing onto ordinary filter 

 paper (Figure 9), air dried at room temperature and then weighed on 

 laboratory scales. The weight of the dry filter was recorded prior 

 to its use in the collection process and later subtracted from the gross 

 weight of dry sediment and filter in order to determine the net weight 

 of dry sample. The weight in grams thus determined was tabulated for 

 use in summarizing the test results. 



Orientation of Intake Nozzle 



A factor of primary importance to the sampling operation is the 

 nozzle orientation and its degree of disturbance to the flow regime. The 

 particular nozzle orientation evidencing the least disturbance to the 

 flow regime is obviously the one most likely to insure collection of a 



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