| 摘要 |
Improved overflow protection for washing machines and other applications in which a liquid from a controllable valve fills a tub is achieved by a circuit in which a single pulse train generated cooperatively by a pressure sensor and a controller is monitored by a lockout timer. If an interruption in the train of pulses occurs that is longer than a predetermined time-out period indicating a failure of either the pressure sensor or the controller that would otherwise prevent the valve from shutting off the flow of liquid into the tub, the lockout timer will cause the valve to turn off. The controller is also able to override the lockout timer and cause a relay to shut off power to the controllable valve to force it off if the pressure sensor detects a continued rise in liquid level after the controller has signalled the controllable valve to shut off.
|
