| 摘要 |
<p>The geothermal well sinking system consists of drilling down to the desired depth and lining the well as necessary. A tube of plastics closed at the bottom, is lowered into the well, there being a clearance between (17) and the walls (1) of the latter or the metal lining (3). After removal of the lining, the intervening annular space between tube and walls is filled up, to give the necessary thermal contact. This can typically be effected by the collapse of the surrounding earth against the tube. Alternatively, the well can be drilled into underground water, which fills up the space concerned, or the latter can be backfilled with the soil excavated or injected with mud, water etc.</p> |
