Dishwashers do not have a direct mechanism to sense the dirtiness of the dishes in the same way that, for example, your eyes can see dirt. Instead, they use a combination of technologies and sensors to optimize the cleaning process based on factors like water temperature, water turbidity, time, and detergent usage. Here's how it generally works:
Water Turbidity Sensors: Many modern dishwashers are equipped with water turbidity sensors. These sensors detect the cloudiness or turbidity of the water in the dishwasher during the wash cycle. As the dishwasher cleans the dishes, the water becomes dirtier with food particles and debris. The turbidity sensor measures the level of cloudiness, indicating how much cleaning the dishes still need. Based on this information, the dishwasher can adjust the wash cycle's duration and intensity.
Temperature Sensors: Dishwashers also have temperature sensors that monitor the water's temperature throughout the wash cycle. Higher water temperatures generally lead to better cleaning results, as hot water helps dissolve grease and stuck-on residues. The dishwasher can adjust the temperature based on the selected wash cycle and the initial temperature of the incoming water.
Timer and Programming: Dishwashers come with pre-programmed wash cycles optimized for different levels of dirtiness and types of dishes. For example, there might be separate cycles for lightly soiled dishes, heavily soiled dishes, delicate items, and more. You can choose the appropriate cycle depending on how dirty your dishes are.
Spray Arms and Water Jets: Dishwashers use spray arms and water jets to direct water onto the dishes. The force and direction of the water jets can be adjusted based on the selected wash cycle, which helps optimize cleaning performance.
Detergent and Rinse Aid Dispensers: The amount of detergent and rinse aid dispensed during the wash cycle is carefully controlled. The dishwasher calculates the appropriate amount of detergent and rinse aid based on the selected cycle and the load's dirtiness level.
User Input: Some high-end dishwashers come with advanced settings that allow users to input information about the load, such as the level of dirtiness, how greasy the dishes are, or if they have tough stains. This information is used to adjust the wash cycle accordingly.
In summary, dishwashers use a combination of water turbidity sensors, temperature sensors, predefined wash cycles, spray arms, and user inputs to optimize the cleaning process for different types of loads. This automation and sensor technology help ensure that dishes are effectively cleaned while conserving water and energy.