Spiral coil heat exchanger of geothermal well and using and mounting method thereof

The invention relates to a spiral coil heat exchanger of a geothermal well and belongs to the technique of geothermal energy development and utilization. Structurally, the upper part of the spiral coil heat exchanger is a metal sleeve insulation area I and the lower part of the spiral coil heat exchanger is a spiral coil heat exchanger area II. The metal sleeve insulation area I is structurally provided with a metal outer sleeve and an inner sleeve. The spiral coil heat exchanger area II is structurally encircled to a ring barrel by a central shaft pipe, a metal sieve pipe, an upper pipe plateand a lower pipe plate. The upper ends of the central shaft pipe and the metal sieve pipe are in hermetical abut joint to the inner sleeve and the metal outer sleeve. The lower ends of the central shaft pipe and the metal sieve pipe are in hermetical abut joint to a semispherical housing at the lower end at the lower pipe plate. A spiral coil in the ring barrel winds around the central shaft pipe. The upper and lower end