NSWC/WOL/TR 75-3 5 



3.1.3 Samplers 



The essential requisite of a satisfactory water sampler is that 

 it should capture a truly representative sample of the water at the 

 sampling depth and bring it to the surface unaltered. This necessi- 

 tates rapid filling with the water surrounding it when open, and 

 perfect sealing when closed. The interior of the sampler should be 

 resistant to corrosion and should not contaminate the sample. Where 

 serial sampling is to be carried out at various depths, it is advan- 

 tageous for the sampler to be light in weight so that sampling can 

 be carried out over the normal range of depth with one cast. 



There are at least two dozen different water sampling bottles 

 in major use, each serving a particular purpose. Bottles are 

 usually opened in-situ by means of weights, or messengers, dropped 

 down the supporting hydrographic wire. Owing to the danger of 

 contamination, metallic samplers should not be used if samples are 

 to be analyzed for trace metals. For such work, the use of plastic 

 water bottles is essential. 



Three types of sampling bottles are recommended here: 



(1) Van Dorn Water Sampler Model XRB-13 

 (Hydro Products, San Diego, California) - Fig. 2 



Specifications 



Sample size: 3 liters 



OD of sample tube: 5.5 inches 



Length of sampler: 12 inches 



Weight in air: 5 3/4 lbs 



Weight in water: 2 lbs 



Weight with sample: 15 lbs 



Price $175 



The Hydro Products XRB series water sampler design is an 

 improved version of the classic Van Dorn design. The main body of 

 the sampler is a chemically inert, rugged PVC tube which offers free 

 flushing feature to assure that the water sample is that of the 

 particular depth at which it was triggered, not a mixture of surface 

 and intermediate waters. 



Operation is a one-operator job, even in rough waters. The 

 sampler can be rapidly affixed to a hydrographic wire. The unit is 

 cocked using a fast, simple operation. When the sampler is triggered 

 by a messenger at a desired depth, the PVC end caps are released and 



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