| 摘要 |
A two-stage electric water heater adapted to store water at a comparatively low temperature and to heat the outflowing stored water to a desired higher temperature includes a storage vessel provided with an elongated thermostatically controlled electric resistance heating element positioned in the vessel and surrounded in space-apart relationship by an elongated imperforate metal tube having a closed outer end attached to a wall of the vessel and an open inner end at a higher level in the vessel and terminating short of the top of the vessel. A heated water outlet extends from the outer end of the tube to the outside of the vessel. An elongated tubular thermally insulating body concentrically surrounds a major part of the length of the tube and is spaced therefrom to form a convective water flow passage communicating with the interior of the vessel proximate the inner and outer ends of the tube. During non-consumption water flows upward through the water flow passage and is heated to a medium temperature by heat transfer from the metal tube for storage in the vessel. During consumption the stored water flows from the vessel into the tube through the open end thereof and is heated to a high temperature by direct contact with the electric heater prior to discharge through the outlet for consumption.
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