초록 ▼

A fabric treating apparatus, such as a domestic clothes dryer, is provided with a digital control circuit and a sensor system which cooperate to terminate a fabric treatment operation when the fabric reaches a desired condition. A digital counter receives and accumulates timing pulses. A sensing cir

A fabric treating apparatus, such as a domestic clothes dryer, is provided with a digital control circuit and a sensor system which cooperate to terminate a fabric treatment operation when the fabric reaches a desired condition. A digital counter receives and accumulates timing pulses. A sensing circuit repetitively charges a capacitor which is allowed to discharge through a sensor in contact with the wet fabric load. If the fabric in contact with the sensor is wet, the capacitor will quickly discharge. As the fabric dries the capacitor will discharge more slowly. After the capacitor has been allowed to discharge for a preselected period, the charge on the capacitor is read and if low, the counter is reset. As the fabric load approaches the desired dryness condition, the remaining charge on the capacitor will increase until it reaches a level which prevents the counter from being reset. Thus, the counter accumulates successively greater counts before being reset, until eventually a preselected count is accumulated in the counter which triggers cicruitry to terminate the fabric drying operation.

대표청구항 ▼

A control circuit for a dryer comprising: a source of timing pulses; a resettable counter arranged to be incremented in accordance with said timing pulses; moisture sensing means operative to sense the moisture content of the clothes load and reset said counter at a rate proportional to the sensed m

A control circuit for a dryer comprising: a source of timing pulses; a resettable counter arranged to be incremented in accordance with said timing pulses; moisture sensing means operative to sense the moisture content of the clothes load and reset said counter at a rate proportional to the sensed moisture content; said moisture sensing means comprising a conductivity sensor arranged to contact the fabric load and a microcomputer input/output port means for charging a capacitance means; said capacitance means arranged to discharge through said conductivity sensor; said port means arranged to selectively read the charged value of said capacitance means and reset said counter if said charged value is less than a predetermined value; and control logic means for terminating the drying operation upon accumulation of a preselected count in said resettable counter.