Graseby 3000/500, Manual

Page: 87 / 231

G r a s e b y M e d i c a l L t d .
5 — 8
5
I s s u e A ( A p r i l 2 0 0 2 )
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
V o l u m e t r i c I n f u s i o n P u m p s
valve opens to allow
fluid flow to upper
valve closed while
upper piston draws
upper piston draws
lower piston moves
forward to deliver
overpressure piston
monitors downline
Figure 5.4 Pumping cycle
valve closes when
upper chamber is full
valve opens to allow
flow to lower piston
upper piston moves
forward
overpressure piston
monitors downline
pressure in set
lower piston draws
back to fill
Figure 5.5 Pumping cycle