Siemens ADVIA 2400 Operator's Manual page 23

Figure 1-15 Reaction tray washer
The reaction washer (WUD) washes reaction tray (RRV) cuvettes after sample analysis is
complete. This allows the reuse of cuvettes without the risk of contaminating the next
sample.
The WUD has seven nozzles, each performing a stage of the wash. Each nozzle works on
a different cuvette, so the WUD washes seven cuvettes simultaneously (the cuvettes are
being washed in different stages at the same time).
After a cuvette is washed by one nozzle, it moves to the next until washing is complete.
While the RRV rotates, the WUD is in the up position.
The wash liquids pass through a preheater before they reach the WUD.
System Overview 23