| 摘要 |
An electric water heater has an inlet, an outlet and a series of consecutive pipe sections arranged in a zig-zag configuration through which water flows in passing from the inlet to the outlet. The zig-zag configuration is such that in use the pipe sections are one above the other in a common plane and each pipe section is inclined to the horizontal at an angle of 30-75 degrees such that a substantial upwards convection force is produced propelling the water from the inlet to the outlet. Each pipe section has a first end, second open end and a side wall opening adjacent the first end and is provided with a unitary tubular member adjacent the first end and having a lateral tubular extension communicating with the side wall opening of the pipe section. Each pipe section has an elongated electric immersion heater supported by the tubular member and extending into the pipe section from the first end. The lateral extension of the tubular member of the first section is connected to the water inlet. The second open end of each pipe section but the last is connected to the lateral extension of the tubular member on the next pipe section. The second open end of the last pipe section is connected to the water outlet. A sequencer is provided for sequentially energizing the heating elements beginning with the uppermost element.
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