Laundry machine, control and method

Abstract

The present invention relates to a method for determining load size in a washing machine. A sensor detects the water level, step 51, in the machine before a recirculation pump is activated, step 50, and after it is de-activated, steps 52-54. The load size can be calculated from the difference in water level, steps 55, 56.

1 . A laundry machine comprising:
 a spin basket,   a sump below said spin basket,   a drive assembly for rotating said spin basket,   a pump for recirculating wash liquid from said sump into said spin basket,   a water level sensor for measuring the water level in said sump and providing an output,   a controller connected to receive said output from said water level sensor and control activation of said pump, said controller programmed to determine a size of a laundry load held in said spin basket based on analysis of changing water level in the sump.   
   
   
       2 . A laundry machine as claimed in  claim 1  wherein said analysis relating to the rate at which free wash liquid drains from a saturated laundry load and collects in said sump and/or the volume of free wash liquid held by the saturated clothes load during recirculation. 
   
   
       3 . A laundry machine as claimed in either  claim 1  or  claim 2  wherein said analysis uses water level output from said sensor under two operating conditions:
 with the pump recirculating wash liquid into the spin basket, and   with the pump not recirculating wash liquid into the spin basket.   
   
   
       4 . A laundry machine as claimed in either  claim 1  or  claim 2  wherein said analysis uses water level output from said sensor read on at least two occasions, at least one said occasion being after ceasing to recirculate wash liquid in the spin basket. 
   
   
       5 . A laundry machine as claimed in  claim 4  wherein said controller is programmed to determine a size of a laundry load held in said spin basket by comparing a first water level output taken while recirculating water through said wash basket with a second water level output taken after ceasing to recirculate water through said wash basket. 
   
   
       6 . A laundry machine as claimed in  claim 5  wherein said second water level output is taken a predetermined time after ceasing to recirculate wash liquid through said basket. 
   
   
       7 . A laundry machine as claimed in  claim 5  wherein said second water level output is taken at a time when free liquid in the laundry load would not be expected to be completely drained to the sump for any of the normal washload sizes. 
   
   
       8 . A laundry machine as claimed in  claim 1  including a tub (or enclosure), said drive assembly includes a shaft extending through a wall of said tub (or enclosure) and said spin basket is supported within said tub (or enclosure) for rotation about the same rotation axis as said shaft,
 said sump being, or being located at, the lower portion of said tub (or enclosure) such that liquid in said tub (or enclosure) collects at said sump.   
   
   
       9 . A laundry machine as claimed in  claim 8  wherein said spin basket is supported by said shaft. 
   
   
       10 . A laundry machine as claimed in either  claim 8  wherein said shaft rotates around a vertical axis, and said tub and said spin basket are accessible through a top opening. 
   
   
       11 . A laundry machine as claimed in  claim 10  including an agitator in said spin basket, driven by said drive assembly, and a clutch for selectively connecting said spin basket to said drive assembly. 
   
   
       12 . A laundry machine as claimed in either  claim 10  wherein said shaft of said drive assembly protrudes from below a base portion of said tub, a stator of an electric motor is fixed to said tub, and a rotor of said electric motor is fixed to said shaft. 
   
   
       13 . A laundry machine as claimed in  claim 12  including a cabinet, and a plurality of suspension members extending between an upper portion of said cabinet and a lower portion of said tub, said suspension members supporting said tub, spin basket, drive assembly and motor within said cabinet. 
   
   
       14 . A laundry machine as claimed in  claim 13  wherein said motor is of the external rotor type. 
   
   
       15 . A laundry machine as claimed in  claim 14  wherein said laundry machine includes a power supply circuit connected with windings of said motor, and said controller has outputs connected to said power supply circuit for controlling the application of power to said windings of said motor, said controller being programmed to drive said drive assembly in at least a first mode involving s slow rotation of said spin basket while said pump recirculates wash liquid into said spin basket. 
   
   
       16 . A laundry machine as claimed in  claim 8  wherein said basket is supported to rotate about a horizontal or inclined axis. 
   
   
       17 . A laundry machine as claimed in  claim 9  wherein a nozzle adjacent an open end of said basket directs recirculating water onto the laundry load. 
   
   
       18 . A laundry machine as claimed in  claim 8  wherein said basket is supported by a shaft at both ends to rotate around a horizontal or inclined axis, and wherein an access hatch or door is provided in the side surface of said wash basket. 
   
   
       19 . A laundry machine as claimed in  claim 18  wherein recirculating wash liquid is provided to said basket along one or both supporting shafts. 
   
   
       20 . A control for execution in a laundry machine having:
 a spin basket,   a sump below said spin basket,   a drive assembly for rotating said spin basket,   a pump for recirculating wash liquid from said sump into said spin basket, and   a water level sensor for measuring the water level in said sump and providing an output;   said control determining a size of a laundry load held in said spin basket based on analysis of changing water level in the sump.   
   
   
       21 . A control as claimed in  claim 20  wherein said analysis relating to the rate at which free wash liquid drains from a saturated laundry load and collects in said sump and/or the volume of free wash liquid held by the saturated clothes load during recirculation, 
   
   
       22 . A control as claimed in either  claim 20  or  claim 21  wherein said analysis uses water level output from said sensor under two operating conditions:
 with the pump recirculating wash liquid into the spin basket, and   with the pump not recirculating wash liquid into the spin basket.   
   
   
       23 . A control as claimed in either  claim 20  or  claim 21  wherein said analysis uses water level output from said sensor read on at least two occasions, at least one said occasion being after ceasing to recirculate wash liquid in the spin basket. 
   
   
       24 . A control as claimed in  claim 23  wherein said controller is programmed to determine a size of a laundry load held in said spin basket by comparing a first water level output taken while recirculating water through said wash basket with a second water level output taken after ceasing to recirculate water through said wash basket. 
   
   
       25 . A control as claimed in  claim 24  wherein said second water level output is taken a predetermined time after ceasing to recirculate wash liquid through said basket. 
   
   
       26 . A control as claimed in  claim 24  wherein said second water level output is taken at a time when free liquid in the laundry load would not be expected to be completely drained to the sump for any of the normal washload sizes. 
   
   
       27 . A method of determining the size (weight) of a laundry load in a laundry machine, the machine having a spin basket, a sump below said spin basket, a drive assembly for rotating said spin basket, a pump for recirculating wash liquid from said sump into said spin basket, and a water level sensor for measuring the water level in said sump and providing an output, said method comprising: determining a size of a laundry load held in said spin basket based on analysis of changing water level in the sump. 
   
   
       28 . A method as claimed in  claim 27  wherein said analysis relating to the rate at which free wash liquid drains from a saturated laundry load and collects in said sump and/or the volume of free wash liquid held by the saturated clothes load during recirculation. 
   
   
       29 . A method as claimed in either  claim 27  or  claim 28  wherein said analysis uses water level output from said sensor under two operating conditions:
 with the pump recirculating wash liquid into the spin basket, and   with the pump not recirculating wash liquid into the spin basket.   
   
   
       30 . A method as claimed in either  claim 27  or  claim 28  wherein said analysis uses water level output from said sensor read on at least two occasions, at least one said occasion being after ceasing to recirculate wash liquid in the spin basket. 
   
   
       31 . A method as claimed in  claim 30  wherein said controller is programmed to determine a size of a laundry load held in said spin basket by comparing a first water level output taken while recirculating water through said wash basket with a second water level output taken after ceasing to recirculate water through said wash basket. 
   
   
       32 . A method as claimed in  claim 31  wherein said second water level output is taken a predetermined time after ceasing to recirculate wash liquid through said basket. 
   
   
       33 . A method as claimed in  claim 31  wherein said second water level output is taken at a time when free liquid in the laundry load would not be expected to be completely drained to the sump for any of the normal washload sizes.