Check Valves

[HAZMAT]

The Dolan article was very interesting, especially the bit where the apparent buildup was remove with high temperature flame.

I wonder exactly what chemistry is responsible for the filming on ruby/sapphire balls/seats. Is the buildup acrylonitrile or something similar?

I just had to pull and sonicate the inlet checkvalves in an SSI pump that probably has less than 25 running hours on it. We've been running methanol, acetone, and acetonitrile through it. Downtime can be very frustrating and expensive. Thats why we switch everything to Opti-max ceramic cartridges when the OEM stops working. Ceramic components seem to solve the problem completely.

[laserman]

I rarely have check valve problem.
I always replace all line to methanol while I do not use HPLC. If I do not want to stop running HPLC, I will keep flow rate 0.1 mL/min
If you are using Waters Alliance, sometimes switching left check valve to right is effective. I do not recommend to do it. This way is just for emergency.