Belimed Washer-Disinfectors: The Dynamic Fill Process

Authored by Jonathan Carfora, Technical Services Trainer

In order for an automated washer to work properly it must have just the right amount of water inside the wash chamber:

• Use too little water and you will get poor cleaning results and the potential for failed cleaning verification tests.
• Use too much water and you consume additional detergent and energy, increasing the overall cycle time.

The ‘just right’ amount of water can be hard to determine. Variables such as washer rack size and the number of instruments being cleaned will change this optimal level. The optimal water volume required to clean a lightly loaded washer will be different than what is required to clean one with a heavy load.

This is why Belimed washers are designed to automatically perform a dynamic filling process. This process ensures that the optimal water volume is used in every wash cycle regardless of the type of rack being used or the number of instruments being washed.

This is achieved by a two-part process:

1. The washer initially fills to a standardized water level. This level never changes and is known as the static fill. The purpose of the static fill is to ensure there is enough water volume inside of the machine to allow the wash pump to run without damaging it.
2. After achieving the static fill level, the wash pump starts. While the pump is running, the washer will continue to fill to a dynamic fill level. The volume of water added during this step will vary based on how much the washer is loaded. More water will be used for heavier loads while less water is used for lighter loads.

The figure below shows water level compared to time during the dynamic fill process.

Water is admitted into the washer causing level to rise. Level is read as a voltage reading and shown on the y-axis. Water level increases until it reaches ‘4’ on the graph. This is the static fill level. At this point, the wash pump turns on.

Water level initially drops after the pump starts. This is due to water from the chamber now filling the pump cavity. Water continues to be added to the wash chamber until the appropriate dynamic fill level is reached represented by ‘5’ on the graph.

Advantages of using the dynamic fill process:

• There is always the optimal amount of water in the wash chamber to achieve the desired cleaning performance.
• Adequate rinsing pressure and water volume.
• The washer does not use more water than necessary.
• Water and detergent consumption are minimized, reducing operational costs.