Spray arms

Magnetic sensors for controlling the movements of the water spray arms in dish washers... 

Another application for reed sensors in modern dishwashers is within the spray-arm control device. This application is very important in protecting the dishes, and even the dishwasher itself, from damage. 

A reed sensor is mounted either above or underneath the spray-arm, outside of the washing area, while a magnet is placed on the spray-arm. The reed sensor counts the revolutions of the spray-arm. If for any reason the spray-arm is not working (Dishes inside the dishwasher could block the movement, or the spray-arm is faulty, etc.), the sensor will indicate on a small outside light or display that service is needed. An additional electronic device could also be activated with this reed sensor to stop the machine, so that the dishes or the machine itself will not be damaged. 

Bevans, R. S., Univ. Mich. Conf. on Fuel Sprays, Armed Services Tech. Inform. Agency... 

Figure 9.12 Equipment Schematic 1 - Filters 2 - Air fan 3 - Spray arm 4 - Spray gun/nozzle, 5 - Direction of movement of product bed 6 - Expansion chamber 7 - Product bowl 8 - Sample probe 9 - Heated/dehumidified inlet air-flow 10 - NIR probe 11 - NIR monochromator 12 - PC. Reprinted from Frake etal. (199 7)75 with permission from Elsevier.

The addition of acidic additives such as citric acid is very popular in European formulations. The theory behind their use is that if sufficient acid is present in the final rinse solution, the acid converts the carbonate and bicarbonate ions into water and carbon dioxide, preventing the formation of insoluble salts. Citric acid formulations may also keep the dishwasher surfaces and nozzle of the spray arms free of limescale deposits. It is also believed that citrate may contribute to the brilliancy or shiny appearance of siliceous surfaces [175],... 

Direct measurement of foam volumes in typical dishwashing machines is usually not possible because of the absence of an observation port. Effectiveness of foam control is therefore inferred from either measurement of the pump pressure or the speed of rotation of the spray arms. The latter can be measured using, for example, magnet and inductive sensors at the extremities of the spray arms [106]. 

Hr Don t overpack the cutlery basket. Knife points and fork tines should go heads down for safety. Make sure spoon surfaces are separated so water can flow between them. (Mix different types in the same compartments so they don t nest.) Lay very long pieces in the upper basket, as they can impede the spray arm. Put small teaspoons in the special spoon basket if your model has one. 

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