WATER-PRESSURE OPERATED CONTROL-SYSTEM FOR DISHWASHERS

The techniques of fluid logic, or fluidics, can be used in control systems for automatic washing machines. The systems operate from the water pressure and are simple and compact. The article describes a prototype designed for dishwasher control. After a brief survey of the various types of fluidic element (dynamic, quasi-static and static) a description is given of the elements used in the prototype, generally baffle nozzles and diaphragm elements. The elements are mainly of the quasistatic type, i. e. they use water in one of two states. Next a description is given of the operation of the dishwasher and of its program of operations. The practical basis of the design of the system is a sandwich construction of plastic plates and rubber sheets, in which the rubber sheets act as a seal and also form the diaphragms for the diaphragm elements. Such a system is very compact, and the whole control system measures only about 11. 5 multiplied by 8 multiplied by 5 cm. The system includes the linear motor, consisting of a piston with a valve-controlled rolling diaphragm, and the pressostat, consisting of a large diaphragm which, under the action of water pressure in the machine, operates baffle nozzles when specific levels are reached. The article concludes with an indication of the application of systems of this kind in ordinary washing machines.