Eicom ENO-30, User Manual

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4. Pump Unit Operation
4-1. Pump overview
The ENO-20 has the very precise liquid delivery pump with double pistons. The reciprocal action of the 2
pistons provides for continuous pulseless flow of the mobile phase.
Outlet Check Valve
At the top each side of the pump head (2 per pump), there is an outlet check valve. This valve
prevents solution from flowing back into the pump. This is a very sensitive; be very careful to not
over-tightened when using a wrench. The internal parts can be crushed and the part will need to
be replaced
Inlet Check Valve
At the bottom of each side of the pump head, (2 per pump), there is an inlet check valve. This
valve also prevents solution from flowing from the pump back to the reservoir. This is very
sensitive; be very careful to not over-tightened when using a wrench. The internal parts can be
crushed and the part will need to be replaced
How it Works
As each piston movers forward the outlet check valve opens and the fluid is sent to the columns
at high pressure. Then as the piston starts to move back, the outlet check valve with close and
the inlet check valve will open so that the piston space can will with fluid. The cycle is completed
as the piston begins forward again; at which time, the inlet check valve closes and the outlet
valve opens.
Check Valve (Outlet)
Pump Head
Front
Mobile Phase
(Inlet)
Check Valve (Inlet)
Piston Seal
Back up Ring
O-Ring
Seal Washing Liquid Space
Pump Head Guide
Piston
Washing Seal
Rod
Guide Ring