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Pumping Operation
Pumping Mechanism
The pumping mechanism is linear peristaltic with 2 active valves. Pumping occurs when the expulsor
presses on the reservoir tubing in sequence with the inlet and outlet valves. At rest, the outlet valve is
pressing down fully on the tubing, and the expulsor and inlet valve are retracted.
Motor
Camshaft
Lock Button
Latch Lever
Upstream Occlusion
Sensor
Pressure Plate
Pump Tubing
Cassette Hinge
Air Detector
Sensor
Downstream
Occlusion Sensor
Expulsor
Pump Housing
Inlet Valve
Outlet Valve
A simulated pumping mechanism in a CADD®-Solis pump:
Upstream Occlusion
Sensor
Air Detector
Sensor
Downstream
Occlusion Sensor
Expulsor
Cassette Sensors
Inlet Valve
Outlet Valve
Bottom view:
When the microprocessor commands the mechanism to pump, the camshaft begins to rotate, thus
controlling the following pump cycle:
1. The inlet valve closes.
2. In synchrony with the expulsor moving down to compress the tubing, the outlet valve opens,
expelling fluid.
3. The outlet valve closes.
4. The inlet valve opens as the expulsor is retracted, causing fluid from the reservoir to again fill the
pump tubing segment.
5. The camshaft rotation stops after ½ revolution, and the cycle is completed.
