The Model 425 Discrete Interval Sampler provides a no-purge sampling option for collecting groundwater samples from discrete levels, and points of inflow, in wells and boreholes. It can also be used for profiling open water bodies, and for sampling above and below oil/product layers, as well as the actual product (e.g. LNAPL and DNAPL).
The stainless steel Discrete Interval Sampler is available in 1", 1.66", and 2" diameters. Operation is up to 500 ft. below water level. The samplers are connected to a length of LDPE tubing, which is wound onto a reel. The reel has a connection for a high pressure hand pump and a pressure/vent switch.
The pump is used to apply pressure and seal the Discrete Interval Sampler before it is lowered. This prevents water from filling the sampler, until it reaches the chosen depth. Once the sampler reaches depth, the pressure is vented and hydrostatic pressure fills the sampler. Before retrieval, the sampler is repressurized to ensure there is no mixing of water from different levels on the way up.
At surface, the pressure is released to allow the sample to be decanted using the sample release device. This regulates flow and minimizes sample degassing, suitable for VOC sampling.