Low voltage sensor for dryer
First Claim
1. A control circuit for use in a dryer during a drying operation 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 a clothes load and reset said counter at a rate proportional to the sensed moisture content;
said moisture sensing means comprising conductivity sensing means arranged to contact the fabric load;
comparator means arranged to compare the sensed conductivity against a predetermined value and to emit a low voltage level if said sensed conductivity is above said predetermined value and to emit a high voltage level if said sensed conductivity is below said predetermined value,circuit means arranged to receive said voltage level and reset said counter if said voltage level is low; and
control logic means for terminating the drying operation upon accumulation of a preselected count in said counter.
1 Assignment
0 Petitions
Accused Products
Abstract
A fabric treating apparatus, such as a domestic clothes dryer, is provided with a microcomputer controlled circuit and a sensor system which cooperates to terminate a fabric treatment operation when the fabric reaches the desired condition. A conductivity sensor senses the moisture content of the fabric within the drying zone. A sensing circuit electrically connected to the sensor generates a voltage level proportional to the moisture condition sensed. The microcomputer reads the voltage level at spaced intervals in time and generates a valid wet signal whenever a given consecutive number of readings indicate a wet condition of the fabric within the drying zone. A counter within the microcomputer counts pulses from a source of timing signals and is repeatedly terminated and restarted whenever a valid wet signal is generated. The fabric drying operation is terminated upon the accumulation of a preselected count in the counter such that the termination coincides with an optimum dryness condition.
-
Citations
10 Claims
-
1. A control circuit for use in a dryer during a drying operation 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 a clothes load and reset said counter at a rate proportional to the sensed moisture content; said moisture sensing means comprising conductivity sensing means arranged to contact the fabric load; comparator means arranged to compare the sensed conductivity against a predetermined value and to emit a low voltage level if said sensed conductivity is above said predetermined value and to emit a high voltage level if said sensed conductivity is below said predetermined value, circuit means arranged to receive said voltage level and reset said counter if said voltage level is low; and control logic means for terminating the drying operation upon accumulation of a preselected count in said counter. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. In a fabric treatment apparatus having means defining a fabric treatment zone and means for treating fabrics placed therein to a predetermined condition, a control for terminating said treatment operation comprising:
-
a source of timing signals; a microcomputer counter means arranged to be incremented in accordance with pulses derived from said source of timing signals; a low voltage sensing means associated with said fabric treatment zone for sensing a parameter related to said predetermined fabric condition and operative to reset said counter at a rate dependent upon the level of said sensed parameter; said low voltage sensing means comprising sensing means arranged to contact the fabric load; comparator means arranged to compare the sensed parameter with a predetermined value and to emit a low voltage level signal if above and a high voltage level signal if below said predetermined value; microcomputer means arranged to receive said signal and reset said counter if said sensed parameter is greater than said predetermined value; and circuit means for terminating said fabric treatment operation in response to the accumulation of a preselected count in said counter means.
-
-
8. A method of controlling a fabric treating apparatus having a treatment zone and means for effecting at least one fabric treating operation, comprising the steps of:
-
(a) initiating a fabric treating operation; (b) sensing a parameter related to the condition of the fabric within the treatment zone; (c) generating a low signal when said sensed parameter is more than a predetermined amount, and otherwise generating a high signal; (d) counting pulses from a source of timing signals on a counter; (e) reading said signal at spaced intervals in time; (f) generating a valid signal whenever a given consecutive number of said readings indicate a sensed parameter more than a predetermined amount; (g) repeatedly terminating and restarting the count in the counter in response to the generation of said valid signal; and (h) terminating the fabric treating operation upon the accumulation of a preselected count in the counter.
-
-
9. A method of controlling a fabric drying apparatus having a drying zone and means for effecting at least one fabric drying operation, comprising the steps of:
-
(a) initiating a fabric drying operation by flowing temperature conditioned air through a drying zone charged with a batch of fabrics to be dried; (b) sensing the moisture content related to the condition of the fabric within the drying zone; (c) generating a low voltage level when a wet condition is sensed; (d) generating a high voltage level when a dry condition is sensed; (e) counting pulses from a source of timing signals on a counter; (f) reading said voltage level at spaced intervals of time; (g) generating a valid wet signal whenever a given consecutive number of said readings indicate a wet condition of the fabric within the drying zone; (h) repeatedly terminating and restarting the count in the counter in response to the generation of said valid wet signal; and (i) terminating the fabric drying operation upon the accumulation of a preselected count in the counter, whereby termination will coincide with an optimum dryness condition. - View Dependent Claims (10)
-
Specification