Graseby 3000/500, Manual

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3 — 5
G r a s e b y M e d i c a l L t d .
3
3 0 0 0 / 3 1 0 0 a n d 5 0 0 / 5 0 5 S e r v i c e M a n u a l I s s u e A ( A p r i l 2 0 0 2 )
V o l u m e t r i c I n f u s i o n P u m p s
How the pump works
This section provides a overview of how the pump works. Further
details are provided in Chapters 5 to 8.
For details of how to use the pump, refer to the Instruction Manual
and the Technical User Manual .
Microprocessors
The pumps contain a central system control microprocessor (CPU1),
with two peripheral microprocessors used for display control (CPU3)
and fail-safe system monitoring (CPU2). The central microprocessor
controls all user programmable functions, alarm condition sensors,
and inter-processor communications.
Pumping mechanism
The central microprocessor also controls a 4-phase stepping motor
which is used to operate the pumping mechanism. Smooth fluid
delivery is accomplished by uninterrupted forward rotation of the
pumping mechanism when the pump is running.
Door latch open
Pulling the door latch handle open moves the cam housing and
pumping mechanism to the load position . The pistons are best
positioned to accept a fluid filled cassette when in the load position .
When the door is opened to turn the pump on, or if the door is opened
while the pump is powering up, the hold light does not turn on until
the motor has backed off to its load position.
Door latch closed
Pushing the door latch closed moves the pumping mechanism to the
operate position .
Completion of cassette loading results in some additional reverse
rotation of the motor as pressure (which develops during the loading
process) on the cassette is reduced and the pumping mechanism
prepares for delivery. To allow up-line pressure release, the over
pressure valve seals the lower fluid pathway during reverse rotation
of the pumping mechanism and reopens upon initial forward rotation.
Free flow prevention system - safety clip
The Free-Flow Prevention System consists of the Safety Clip (located
under the cassette on the administration set) and the mechanical clip
retention slot and associated mechanics on the lower cassette
housing. The Safety Clip must be placed in the retention slot when
loading the cassette, or the pump will not operate.
• When the door is closed the Safety Clip opens to allow fluid
delivery.
• When the door is opened, the Safety Clip closes, preventing
unrestricted gravity flow even when the administration set is
removed from the pump.