Automatic liquid level control

• US 4,303,406 A
• Filed: 03/14/1980
• Issued: 12/01/1981
• Est. Priority Date: 03/14/1980
• Status: Expired due to Term

• Current Assignee: Anvil Technologies LLC
• Original Assignee: Maytag Corporation (Whirlpool Corporation)
• Inventors: Ross, Frank E.
• Primary Examiner(s): Coe, Philip R.
• Application Number:
  US06/130,470
• Time in Patent Office: 627 Days
• Field of Search: 68/12 R, 68/207, 137/387, 8/158
• US Class Current: 8/158
• CPC Class Codes: D06F 2103/18 Washing liquid level
• CPC Class Codes: D06F 2105/42 Detergent or additive supply
• CPC Class Codes: D06F 39/087 Water level measuring or regulating devices
• CPC Class Codes: G01F 13/006 measuring volume in function of time
• CPC Class Codes: G05D 9/12 characterised by the use of electric means

Abstract

An automatic liquid level control system is provided for a laundry appliance having a tub and a perforate fabric basket within the tub. Washing liquid is injected onto the surface of fabrics to be laundered. A portion of the washing liquid will be absorbed by the fabrics and a portion will flow through the fabrics and fabric basket perforations for accumulation in the tub. Sensing devices are provided for monitoring the changing liquid level in the tub and the time required to reach predetermined levels. A programmable controller determines the quantity of additional liquid required to launder the fabric load responsive to the sensing devices and commensurate with the load characteristics and controls the injection thereof onto the fabrics.

Claims

1. An automatic liquid level control system for a laundry apparatus having a tub for containing liquid and a perforate basket within said tub for containing fabrics to be treated, the combination comprising:

inlet means for supplying liquid to said tub and operable for spraying liquid into said apparatus for absorption by said fabrics and flow through said fabrics for accumulation in said tub;

means for measuring the rate of change of liquid level in said tub in the presence of fabrics as a gauge of the total liquid required to treat the specific fabric load in said basket; and

programmable control means including logic circuit means responsive to said measuring means for determining the additional liquid required to provide said total liquid and for controlling said inlet means to provide an additional timed fill to achieve said total liquid.

2. An automatic liquid level control system for a laundry apparatus having a tub for containing liquid and a perforate basket within said tub for containing fabrics to be treated, the combination comprising:

inlet means for supplying liquid to said tub and operable for spraying liquid into said apparatus for absorption by said fabrics and flow through said fabrics for accumulation in said tub;

means for measuring the rate of absorption by said fabrics as a gauge of the total liquid required to treat the specific fabric load in said basket; and

programmable control means including logic circuit means responsive to said absorption measuring means for determining the additional liquid required to provide said total liquid and for controlling said inlet means to provide an additional timed fill to achieve said total liquid.

3. A liquid level control system as described in claim 2 wherein said absorption measuring means includes means for sensing the time to fill said tub to a predetermined first liquid level as a measure of fabric load characteristics in said basket.

4. A liquid level control system as described in claim 2 wherein said absorption measuring means includes means for sensing a predetermined first level of liquid in said tub after a predetermined timed period of fill as a measure of the fabric load characteristics in said basket.

5. An automatic liquid level control system for a laundry apparatus having a tub for containing liquid and a perforate basket in said tub for containing fabrics to be treated, the combination comprising:

inlet means for supplying liquid to said tub by spraying liquid onto the fabrics for absorption by said fabrics and flow therethrough for accumulation in said tub;

means for measuring the rate of absorption by said fabrics as a gauge of the fabric load characteristics in said basket and of the total liquid required to treat a particular fabric load; and

programmable control means including logic circuit means responsive to said absorption measuring means and operable for determining the additional liquid required to provide said total liquid and for controlling said inlet means to inject an additional quantity of liquid into said tub as determined by said control means and commensurate with the sensed fabric load characteristics.

6. A liquid level control system as described in claim 5 wherein said inlet means further includes means for uniformly distributing said liquid onto the surface of said fabrics for absorption and flow therethrough.

7. An automatic liquid level control system for a laundry apparatus having a tub for containing liquid and a perforate basket in said tub for containing fabrics to be treated, the combination comprising:

inlet means for supplying liquid to said tub by spraying liquid onto the fabrics for absorption by said fabrics and flow therethrough for accumulation in said tub;

means for sensing one of (a) the time to fill said tub to a predetermined intermediate liquid level or (b) the level of liquid in said tub after a predetermined intermediate timed period of fill as a measure of the fabric load characteristics in said basket and of the total liquid required to treat a particular fabric load; and

programmable control means including logic circuit means responsive to said sensing means for determining the additional liquid required to provide said total liquid and for controlling said inlet means to inject a said additional quantity of liquid into said tub commensurate with the sensed fabric load characteristics.

8. A liquid level control system as defined in claim 7 wherein said inlet means further includes means for uniformly distributing the liquid onto the surface of said fabrics for absorption and flow therethrough.

9. An automatic liquid level control system for a laundry apparatus having a tub for containing liquid and a perforate basket in said tub for containing fabrics to be treated, the combination comprising:

inlet means for supplying liquid to said tub and for distributing said liquid onto said fabrics for absorption by said fabrics and flow therethrough for accumulation in said tub;

means for sensing the time to fill said tub to a first predetermined liquid level as a measure of the fabric load characteristics in said basket and of the total liquid required to treat a particular fabric load;

means for sensing the time to fill said tub to a second higher predetermined liquid level; and

programmable control means including logic circuit means responsive to said sensing means for utilizing the times to fill to said first and second levels for determining the additional liquid required to provide said total liquid and for controlling said inlet means to inject said additional quantity of liquid into said tub commensurate with the sensed fabric load characteristics.

10. A liquid level control system as defined in claim 9 wherein said control means includes circuitry for providing a first current path prior to attaining said first predetermined liquid level and a second current path upon reaching said first liquid level for controlling operation of said inlet means.

11. A method of automatically determining and providing a liquid level in a laundry apparatus having a tub for containing liquid and a perforate basket in said tub for containing fabrics to be treated, comprising the steps:

injecting liquid into said tub by spraying the liquid onto the fabrics for absorption by said fabrics and flow therethrough for accumulation in said tub;

sensing the time to fill said tub to a first predetermined liquid level as a measure of the fabric load characteristics;

sensing the time to fill said tub to a second higher predetermined liquid level and determining therefrom the time to fill said tub to said first predetermined level without fabrics;

determining the additional quantity of liquid required commensurate with the sensed fabric load characteristics and based upon a comparison of the actual time to fill to said first predetermined level and the time to fill to that level without fabrics; and

injecting said additional quantity of liquid into said tub.