Magnet sensors in Dish washer spray arm jam detection
Dishwashers are appliances used to automatically wash dishes and cutlery, by spraying high pressure hot water and detergent. This is accomplished by rotating spray arms between the shelves and at the bottom of the appliance. As these spray arms rotate and spray water, the high power water spray could dislocate some of the lighter dishes in the carrier and lodge them along the spray arm path. As a result, the next time the spray arm passes, it could jam the system. To overcome such problems, any blockage needs to be sensed and displayed on the main panel so that the user can pause the washing cycle, and correct the jam. This is accomplished with Reed Sensors mounted at the end positions of the spray arms and in strategic position along its path. The spray arm, having the magnet will trigger the reed sensors consecutively, within a specific time span which is proportional to its speed. If a jam occurs, and the set time period between two reed sensor points has exceeded, the processor stops the machine and indicates a jam on the panel.