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Comments
There
are four possible cross-port scratch locations on the rotor seal:
1) When in the LOAD position, a scratch between ports #3 and #4 will allow
fluid to escape in both the LOAD and INJECT positions.The figure illustrates
this case.
2) When in the INJECT position, a scratch between ports #2 and #3 will
not produce leakage outside of the system although it will cause some
flow to bypass the loop. When the rotor seal is turned to LOAD, this scratch
is now between ports #1 and #2, allowing fluid to escape from vent tube
#6 or the needle port.
3) When in the LOAD position, a scratch between ports #5 and #6 will not
produce high pressure leakage. When the rotor seal is turned to INJECT,
this scratch is now between ports #1 and #6, allowing fluid to escape
from vent tube #6.
4) When in the LOAD position, a scratch between ports #4 and #5 will not
cause leakage in either position, but it may allow some sample to bypass
the loop during loading if the loop has a high resistance to flow and
sample is dispensed rapidly.
Rheodyne RheBuild™ Kits are available for all injectors. Kits contain only genuine Rheodyne parts together with tools and instructions.
Symptom #11
System pressure decreases when the injector is switched (to either INJECT or LOAD) and does not return to normal (see Fig. 34).
Cause
A cross-port scratch on the rotor seal allows high pressure mobile phase to escape.
To confirm: Observe the needle port and vent tubes while in the INJECT (or LOAD) position. You will observe the leak at one of these locations. If the needle port or vent tubes were previously full of air, it may take awhile for the fluid to appear.Solution
Replace the rotor seal. Examine the ceramic surface of the stator face assembly and replace the assembly if it is chipped, cracked, or if any of the holes are blocked. Also see Symptom #2 and comments.
Fig. 34. In the LOAD position (A) a scratch between ports 3 and 4 allows high pressure mobile phase (lt. blue) to lead into the needle port. In the INJECT position (B) the scratch moves between ports 4 and 5. The mobile phase now leaks out vent tube #5.
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