System for and method of detecting imbalance of a laundry machine

Abstract

A system and method of using a fluid flow sensor for detection of load imbalance in a laundry machine. The invention includes a laundry machine, wherein the laundry machine includes a housing; a tub disposed in the housing; a drum rotatably disposed in the tub; a motor to rotate the drum; an outflow orifice at substantially the lowest point of the tub; a pump for draining the tub of water during a dewatering phase; and an outflow line between the outflow orifice and the pump. The system further includes a fluid flow sensor disposed inline with the outflow line, wherein the fluid flow sensor senses fluid flow rate variation within the outflow line; and a controller adapted to measure motor speed variation and/or fluid flow rate variation, wherein the controller initiates an imbalance routine when a threshold value of variation in motor speed or fluid flow rate is exceeded.

1 . A system for detecting load imbalance in a laundry machine, comprising:
 a laundry machine, wherein the laundry machine comprises:
 a housing; 
 a tub disposed in the housing; 
 a drum rotatably disposed in the tub; 
 a motor adapted to rotate the drum; 
 an outflow orifice positioned at substantially the lowest point of the tub; 
 a pump for draining the tub of at least water during a dewatering phase; and 
 an outflow line providing a fluidic connection between the outflow orifice and the pump; 
   a fluid flow sensor disposed inline with, and in fluidic connection with, the outflow line of the laundry machine, wherein the fluid flow sensor senses fluid flow rate variation within the outflow line; and   a controller adapted to measure at least motor speed variation of the motor and fluid flow rate variation as sensed by the fluid flow sensor, wherein the controller initiates an imbalance routine when a threshold value of variation in motor speed or fluid flow rate is exceeded.   
     
     
         2 . The system of  claim 1 , wherein the fluid flow sensor is disposed inline with, and in fluidic connection with the outflow line of the laundry machine, and is positioned at a point between the outflow orifice and the pump. 
     
     
         3 . The system of  claim 1 , wherein the fluid flow sensor is disposed inline with, and in fluidic connection with the outflow line of the laundry machine, and is positioned at an outlet end of the pump. 
     
     
         4 . The system of  claim 1 , wherein the imbalance routine comprises stopping rotation of the drum to redistribute a laundry load. 
     
     
         5 . The system of  claim 1 , wherein the controller is adapted to measure the variation in motor speed occurring in one revolution of the drum. 
     
     
         6 . A system for detecting load imbalance in a laundry machine, comprising:
 a laundry machine, wherein the laundry machine comprises:
 a housing; 
 a tub disposed in the housing; 
 a drum rotatably disposed in the tub; 
 a motor adapted to rotate the drum; 
 an outflow orifice positioned at substantially the lowest point of the tub; 
 a pump for draining the tub of at least water during a dewatering phase; and 
 an outflow line providing a fluidic connection between the outflow orifice and the pump; 
   a fluid flow sensor disposed inline with, and in fluidic connection with, the outflow line of the laundry machine, wherein the fluid flow sensor senses fluid flow rate variation within the outflow line; and   a controller adapted to measure at least fluid flow rate variation as sensed by the fluid flow sensor, wherein the controller initiates an imbalance routine when a threshold value of variation in fluid flow rate is exceeded.   
     
     
         7 . The system of  claim 6 , wherein the fluid flow sensor is disposed inline with, and in fluidic connection with the outflow line of the laundry machine, and is positioned at a point between the outflow orifice and the pump. 
     
     
         8 . The system of  claim 6 , wherein the fluid flow sensor is disposed inline with, and in fluidic connection with the outflow line of the laundry machine, and is positioned at an outlet end of the pump. 
     
     
         9 . The system of  claim 6 , wherein the imbalance routine comprises stopping rotation of the drum to redistribute a laundry load. 
     
     
         10 . A method of detecting load imbalance in a laundry machine, comprising:
 providing a system for detecting load imbalance in a laundry machine, comprising:
 a laundry machine, wherein the laundry machine comprises:
 a housing; 
 a tub disposed in the housing; 
 a drum rotatably disposed in the tub; 
 a motor adapted to rotate the drum; 
 an outflow orifice positioned at substantially the lowest point of the tub; 
 a pump for draining the tub of at least water during a dewatering phase; and 
 an outflow line providing a fluidic connection between the outflow orifice and the pump; 
 
 a fluid flow sensor disposed inline with, and in fluidic connection with, the outflow line of the laundry machine, wherein the fluid flow sensor senses fluid flow rate variation within the outflow line; and 
 a controller adapted to measure at least motor speed variation of the motor and fluid flow rate variation as sensed by the fluid flow sensor, wherein the controller initiates an imbalance routine when a threshold value of variation in motor speed or fluid flow rate is exceeded; 
   measuring at least the motor speed variation of the motor and the fluid flow rate variation as sensed by the fluid flow sensor;   determining when the variation in motor speed or fluid flow rate exceeds a threshold value; and   initiating the imbalance routine when the variation in motor speed or fluid flow rate exceeds a threshold value.   
     
     
         11 . The method of  claim 10 , wherein the fluid flow sensor is disposed inline with, and in fluidic connection with the outflow line of the laundry machine, and is positioned at a point between the outflow orifice and the pump. 
     
     
         12 . The system of  claim 10 , wherein the fluid flow sensor is disposed inline with, and in fluidic connection with the outflow line of the laundry machine, and is positioned on an outlet end of the pump. 
     
     
         13 . The method of  claim 10 , wherein the imbalance routine comprises stopping rotation of the drum to redistribute a laundry load. 
     
     
         14 . The method of  claim 8 , wherein measuring at least the motor speed variation of the motor comprises measuring the variation in motor speed occurring in one revolution of the drum. 
     
     
         15 . A method of detecting load imbalance in a laundry machine, comprising:
 providing a system for detecting load imbalance in a laundry machine, comprising:
 a laundry machine, wherein the laundry machine comprises:
 a housing; 
 a tub disposed in the housing; 
 a drum rotatably disposed in the tub; 
 a motor adapted to rotate the drum; 
 an outflow orifice positioned at substantially the lowest point of the tub; 
 a pump for draining the tub of at least water during a dewatering phase; and 
 an outflow line providing a fluidic connection between the outflow orifice and the pump; 
 
 a fluid flow sensor disposed inline with, and in fluidic connection with, the outflow line of the laundry machine, wherein the fluid flow sensor senses fluid flow rate variation within the outflow line; and 
 a controller adapted to measure at least fluid flow rate variation as sensed by the fluid flow sensor, wherein the controller initiates an imbalance routine when a threshold value of variation in fluid flow rate is exceeded; 
   measuring at least the fluid flow rate variation as sensed by the fluid flow sensor;   determining when the variation in fluid flow rate exceeds a threshold value; and   initiating the imbalance routine when the variation in motor speed or fluid flow rate exceeds a threshold value.   
     
     
         16 . The method of  claim 15 , wherein the fluid flow sensor is disposed inline with, and in fluidic connection with the outflow line of the laundry machine, and is positioned at a point between the outflow orifice and the pump. 
     
     
         17 . The system of  claim 15 , wherein the fluid flow sensor is disposed inline with, and in fluidic connection with the outflow line of the laundry machine, and is positioned on an outlet end of the pump. 
     
     
         18 . The method of  claim 15 , wherein the imbalance routine comprises stopping rotation of the drum to redistribute a laundry load.