Model 660 The Drive-Point Profiler®
The Model 660 Profiler is designed to allow collection of samples from multiple points in a single drive/drilling location, at discrete zones.
It allows:
- contaminant vs. depth profiling
- detailed plume delineation
The Model 660 Profiler is a modified version of the profiling device developed at the University of Waterloo and described in a paper presented at the 1994 NGWA Outdoor Action Conference. The Model 660 can be installed with a rig that pushes, hammers or vibrates the Profiler into suitable sands. It uses AW rod, and can be adapted to attach to the custom rod used by some rigs.
The Profiler has a 1.75" (45 mm) dia. AW stainless steel tip with one row of screened inlet holes set circumferentially. The inlet holes lead to a single stainless steel, LDPE or Teflon® sample line which attaches to a pump, typically a Peristaltic Pump.
High Quality Samples
For best results the sample flow is passed, in-line, through a Solinst VOA Bottle Filler and Flow-Through Cell ahead of a Peristaltic Pump. By using the Solinst VOA Bottle Filler, the sample is not exposed to the atmosphere during retrieval and loss of volatiles is thus minimized.
The Flow-Through Cell allows the water to be monitored for conductivity, pH, temperature or other appropriate parameters. When the readings stabilize the operator can be sure that the deionized water has been purged and that the sample bottles now contain fresh formation water.
Sealing Profiler Holes
Holes in most homogenous sands will collapse as soon as the Profiler is withdrawn. In other geologic formations it is best to use a profiler fitted with a grout tip. The grout tip is a single use tip that can be separated from the Profiler with a high-pressure grout pump, after sampling is complete. This allows the hole to be grout sealed as the Profiler is being
withdrawn, ensuring no void spaces.
Operation
Profiling can start at ground surface, or to save time it can begin at the bottom of a pre-drilled hole.
To avoid downward drag and cross contamination due to driving, the Profiler system is flushed with deionized water using a Peristaltic Pump, while it is being driven between sampling zones. When the desired depth is reached, the pump flow is reversed. The resulting water flow is monitored for clarity and conductivity. This can be done using the Solinst Flow-Through Cell (see data sheet #475). When all deionized water is purged from the system and the conductivity has stabilized, the sample is taken. If sampling for volatiles using the Peristaltic Pump, it is advisable to collect samples in-line, ahead of the pump to avoid the stripping of volatiles from the samples. For this the Solinst VOA Bottle Filler, Model 470 can be used.
After sampling, the water flow is reversed and once again deionized water is used to flush the Profiler and keep it from clogging during driving. Tests have proven virtually no drag down if correct procedures are followed.
Depth Limitations
Drive-Point Profilers are not suitable for all sites. The depth limitations vary, especially with soil conditions, the drive technology used and the pumping system used to inject deionized water and withdraw samples. The Peristaltic Pump is used for most applications, but a Double Valve Pump can also be adapted for deeper applications.
There is no limit to the distance between sample depths when using the Profiler and samples each foot are often chosen.
Most drill rigs with AW rod will have the capability to advance the profiler. A tubing by-pass will need to be supplied with the AW drill rod to allow the sample line to exit the rods.
® The Drive-Point Profiler is a registerd trade-mark of Solinst Canada Ltd and
Teflon is the registered trade-mark of Dupont Corporation.
Solinst Canada Ltd.
35 Todd Rd.
Georgetown, ON
L7G 4R8
Phone: (800) 661-2023; (905) 873-2255
Fax: (905) 873-1992
|