By Rebecca on Thursday, February 27, 2003 - 02:30 pm:
I have been using a Shimadzu LC10-AD pump together with a electrochemical
detector.A few days ago I noticed there is pressure fluctuations with the
pump. First I tried to purge pump with isopropanol to bring out air bubble
possibly trapped in the pump. When that didn't help, I sonicated check valve first
in water then in isopropanol.
But the problem remained and to make it worse, the pressure couldn't reach
what I started with and the measured flow rate is lower than the set one.
When I purge, lots of bubbles continued to come out from drain valve. I
guess there must be some internal leak caused by faulty check valve or
plunger seal? How can I identify which part is not working so I can order
it? Currently I don't have any spare ones in hand and can't try them on.
Your suggestion will be highly appreciated.
By Anonymous on Thursday, February 27, 2003 - 09:54 pm:
you can check from pump menu which pump head is giving problem.If there is an leakage from the seals , you have to change them. if not, change the check valve. or try to tight them bit more .
By Russ on Friday, February 28, 2003 - 05:49 am:
In addition to the suggestions above, the inlet check valve has a small clear "plastic" seal which can come loose during sonication. When new they are not difficult to see but after use they get compressed and can be easily lost. If this seal is not in place, you will not get a good seal and significant air leaks are possible. I am assuming you have carefully checked for leaks around the pump heads and pressure transducer. While the pressure transducer normally fails by leaking, we recently had a problem with erratic pressure and bubbles in the line which was fixed by replacing the transducer. This is not the first thing to replace though, as they are not cheap!
By Anonymous on Monday, March 3, 2003 - 06:56 am:
Dear Rebecca,
are you running pure acetonitril?
The black plunger seal will last not longer then 40 to 60 liter with pure acetonitril. Caused some problems at our lab in the beginning.
By Anonymous on Thursday, June 19, 2003 - 08:23 pm:
I'm using LC-10AD also. I used to have a problem with pressure fluctuation. If you have a problem with plunger seal, you will see a liquid leak from washing tube (the plastic tube that's hanging out from the pump head). I think you can also call the technical support of Shimadzu. They're really helpful. If your measuring volume is a half of set value, it's probably a problem with check valve(s).