| 摘要 |
An instantaneous fluid heater having a combined safety shut-off and temperature regulator includes a hollow heater block having a fluid inlet, a fluid outlet and inner walls defining a plurality of interconnected heating chambers forming a serpentine fluid flow path from the inlet to the outlet. A separate electric heating element is positioned in each chamber and a separate thermostat is positioned at the downstream end of each chamber for opening and closing an electrical circuit in response to the temperature at the downstream end. An electrical sequence switching arrangement cooperates with the thermostats to sequentially energize the heating elements, beginning with the heating element in the most downstream chamber. The thermostats are arranged in circuit with the heating elements and sequence switching arrangement to deenergize the heating element in the respective chamber with which the thermostat is positioned upon attainment of a pre-determined temperature at the downstream end of the chamber and for deenergizing the heating element in each chamber upstream therefrom without regard to whether or not the thermostat associated with each upstream chamber is open or closed. The fluid heater includes a flow switch for allowing operation only in response to a minimum fluid flow rate. A safety thermostat is provided at the downstream end of the most downstream chamber to establish a maximum permitted fluid temperature.
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