Abstract: The packing-seal is shown in use in a borehole as a level-isolating seal for a groundwater sampler. The packing-seal shown includes an expandable annulus of Dowell (TM) water-expandable material. Surrounding that is a pressure-sleeve of rubber. A sheet of woven Kevlar (TM) is wrapped circumferentially around the sleeve and the Dowell annulus, such that the ends of the Kevlar sheet overlap. Outside the Kevlar is an outer rubber sleeve. Upon expansion of the packing seal to fill the borehole, the Kevlar sheet unwraps to allow the Dowell to expand without restraint. Once the packing seal has filled the borehole, the Kevlar sheet is prevented from unwrapping further. If the borehole contains a fissure the Kevlar provides a rigid bridge over the fissure, and prevents the packing-seal from ballooning out into the fissure.

Abstract: In use, the probe (1) is dropped into a ground-hole (3), for the purpose of detecting the depth of the steel casing (16) of the hole. The probe comprises a long, slim, tubular housing (2) made of stainless steel. Attached inside the housing is a springy stalk (10) made of PVC. The stalk is deflectable laterally, and carries a magnet (11) at its free end. The magnet responds to the steel, and causes the stalk to deflect while in the presence of the steel. The housing, and a stainless steel sleeve (12) around the magnet, comprise a pair of electrical contacts, which break apart and send a signal to the surface when the magnetic influence disappears. The probe is suspended on a cable (4) which is calibrated to indicate the depth of the probe when the signal is received.