Borehole packer
AssigneeSolinst Canada Limited
InventorsDonald A. Toon, Douglas J. Belshaw
Life of this patent
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Abstract
The packer (4) is for use in isolating long lengths (i.e. heights) of a borehole (2), e.g. between sampling points. The packer includes bentonite (23) which is activated by the natural groundwater in the borehole. The water is admitted into the bentonite through narrow portholes (21), which delays the flow of water into the packer. The water is distributed evenly throughout the bentonite by blotting paper (14,16) which soaks up the incoming water and prevents the water passing to the bentonite until the blotting paper is all saturated. Alternatives to the use of blotting paper, to transmit the water evenly over and through the whole body of bentonite, include perforated corrugated plastic, corrugated cardboard, and perforated plastic pipes.
Claims13
Borehole packer assembly, wherein:
- the assembly includes an inner tube, and an outer tube of elastomeric material that is flexible and stretchable;
- the inner and outer tubes are so dimensioned and arranged as to create an elongate annular chamber therebetween;
- the annular chamber is elongate in the sense that the chamber is many times longer in its axial extent than in its radial extent;
- the assembly includes means for closing off the upper and lower ends of the annular chamber;
- the assembly includes a body of expandable packer material, the material being of the kind which expands considerably when wet, and which becomes impermeable when wet;
- the body of expandable packer material is located in, and substantially fills, the elongate annular chamber;
- the assembly includes an activation port or ports, so disposed as to provide passage between the said chamber and natural groundwater present in the borehole;
- the nature and dimensions of the body of expandable packer material are such that a quantity Q of the groundwater is required to be introduced into the body of material in order for the body to expand sufficiently to fully seal off the borehole;
- the assembly includes a distribution means, which is effective to distribute the quantity Q of the groundwater received via the port or ports throughout the whole body of expandable packer material;
- and the assembly includes a delay means which is effective to delay for a substantial period of time, passage of the full quantity Q of the groundwater from the port or ports, through the distribution means and into the body of expandable packer material.
Dependencies are inferred from the claim text.