| 摘要 |
<p>A controller, for controlling an electrode boiler steam humidifier includes a plurality of current loop transformers, coupled to the boiler electrodes, for sensing the current drawn by the electrode boiler. A current level detector provides a control voltage to a solenoid controlled valve, associated with the boiler, to drain a predetermined quantity of water from the boiler and thereby reduce the electrode current, when the electrode current exceeds a predetermined upper current limit. A resettable counter is provided for limiting the number of automatic attempts which can be made to reduce the electrode current. Normal periodic actuation of the humidistat resets the counter to avoid reaching the predetermined count through long-term acquisition of isolated over-current occurrences. During normal operation of the boiler, the time required for the electrode current to decrease between a pair of predetermined current levels is monitored and is compared against a known reference in order to provide a general indication of the condition of the boiler.</p> |
