38 User manual OR 100 /110, ed. 5
OR 100/110 integrated pulse damper
Principle of operation
The OR 100/110 is equipped with a membrane-type pulse damper with
stainless steel housing. Pump pulsations are strongly suppressed improv-
ing detection limits in HPLC-EC.
The pulse damper reduces pulsations by compressing a fluid held within
the bottom cavity of the unit. This fluid is isolated from the LC mobile
phase by a durable but flexible inert diaphragm. As the LC system pres-
sure increases, the fluid compressed. When the LC pump piston is retract-
ing, the compressed fluid expands maintaining system pressure and, more
important, keeps the mobile phase flowing at a constant rate. When the
system pressure is at its maximum allowable pressure (40 MPa =6000 psi)
the volume of mobile phase in the damper is only 0.9 mL.
Fig. 13. Schematic representation of OR 100 pulse damper
Operation of the pulse damper is automatic. The pulse damper works best
if the pressure is at least 35 bar (500 psi/3.5 MPa) and preferably 70 bar
(1000 psi/7.0 MPa). In case of low pressure it may be desirable to install a
restrictor between damper and injector. The advised operating tempera-
ture is between 15 -35
o
C.
CAUTION: Never induce large and sudden pressure drops in the sys-
tem, because this will damage the internal diaphragm of the pulse
damper resulting in leakage.
To avoid pressure drops, remove fittings of high-pressure tubing only after
the pump is switched off and the pressure has dropped to atmospheric
pressure.
