| 摘要 |
<p>A control for a container (12) such as that in a washing machine for infinitely controlling the temperature of liquid such as water in the container (12) by alternately providing for the flow of hot water through a first passageway (14) and cold water through a second passageway (16) to the container. The control is operable to infinitely vary the temperature of the water in the container between the temperature of the hot water in the first passageway (14) and the temperature of the cold water in the second passageway (16) and includes a first valve (18) for controlling the flow of hot water and a second valve (22) for controlling the flow of cold water to the container (12). A reference signal generator (26) establishes an infinitely variable reference signal indicative of the desired temperature of the water in the container and a temperature sensor (30) senses the actual temperature of water in the container (12) and establishes a feedback signal indicative thereof. The control further includes a first comparator (34) responsive to the reference signal and the feedback signal for establishing an error signal indicative of the error between the desired temperature and the actual temperature of the water in the container. A periodic signal generator (40) is provided for establishing a periodic input signal and a second comparator (46) is responsive to the error signal and the periodic input signal and establishes a periodic output signal having on-time and off-time during each cycle. Switching means (58, 62) are provided responsive to the periodic output signal for energizing the first valve (18) during the on-time of the periodic output signal and energizing the second valve (22) during the off-time of the periodic output signal.</p> |
