Principle Of Operation - Thermo Scientific Wellwash User Manual

Principle of operation

The Wellwash can be used to wash and prepare plates for a variety of test routines, mainly in ELISA
applications. The Wellwash (Figure 1) is a microplate strip washer for automated washing, aspiration,
dispensing and shaking of 96-well plates and strips in landscape or portrait plate orientation. The
instrument is equipped with one wash and one waste liquid bottle each with a cap, tubing and a liquid
level sensor. The Wellwash comes with a 1x8 or a 1x12 wash head. The plate carrier places the
microplate under the wash head to perform the desired operation. During priming the wash head
moves into the priming vessel to fill the liquid line from the liquid bottle to the wash head.
The 96-well plates and strips are designed to be washed with a 1x8 wash head (landscape) or a 1x12
wash head (portrait) (Figure 2). The wash head tips have both dispensing and aspiration channels. In
the washing step, the wash head aspirates continuously and descends until it reaches the bottom of
the well and the liquid is aspirated (Figure 3). In sweep mode, the wash head aspirates in two
positions of the well bottom to enable a low residual volume (Figure 4). When the wash head is in the
upper position, the desired volume is dispensed into the well (Figure 3 and Figure 4). Aspiration runs
continuously, enabling overflow dispensing of large volumes. After the first row or column has been
washed, the next row or column is moved under the wash head for washing.
or
Figure 2. Wash heads
Figure 3. Principle of Wash step (Normal)
Figure 4. Principle of Wash step (Sweep2)
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