CA-500 Series S/M 2-2 Revised December 2001 8
2.2 HYDRAULIC SYSTEM OPERATION
2.2.1 Structure
The hydraulic system consists of the volumetric syringe for volumetric dispensing of samples or reagent, the
filling line using the pressure pump and solenoid valve, and the drain line using the vacuum pump.
2.2.2 Operation
(1) Outline of Hydraulic System Operation
This system's filling and draining are operated by pressure created by the pressure pump and vacuum
pump in the system. Therefore the pressure is applied to the rinse bottle and the vacuum is applied to the
waste bottle.
(a) Filling line
A constant pressure is applied to the rinse bottle. The valve connected to the line opens to feed rinse
solution.
(b) Drain Line
The drain line is released to the atmosphere at the rinse cup. The vacuum pump operates only when
the vacuum to aspirate the waste into the waste bottle. The vacuum is not monitored. Instead,
instrument checks if the liquid level becomes abnormal when the sample probe is moved to the
Probe Rinse Cup (inside) (if liquid is not drained properly, the drain error occurs).
(2) Analysis Starting Operation
(a) Rinsing at Analysis Start
The sample probe moves to the Probe Rinse Cup (outside) to detect the syringe home position. The
probe moves into the Probe Rinse Cup (inside) to remove remaining liquid on the probe tip. The
probe moves to rinse solution position to aspirate CACLEAN I. Aspirated rinse solution is kept in the
probe for a certain time to rinse the probe inside. (This can be changed in Service Program.)
The sample probe moves to the Probe Rinse Cup (inside), and the rinsing solution flows by opening
SV on Rinse Cup. At this time, the syringe piston moves to drain the rinse solution.
The probe moves into the Probe Rinse Cup (outside), and both the Probe Rinse Cup valve and the
valve on probe open to rinse the probe.
(b) Reagent Aspirating and Dispensing
When aspirating sample or reagent, the probe moves to a sample to aspirate, lowers into the test
tube, detects the liquid surface, then the volumetric syringe descends and aspirates the sample. At
this time, the solenoid valve does not operate (keep closed).
When draining, the probe moves to the reaction tube in the Reaction Tube Rack to dispense, the
volumetric syringe ascends and dispenses the sample. After that, the probe moves to home position,
and moves to the Probe Rinse Cup (inside).
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