System run dry - pump issues?

TimmyTrendy

<p><span>Hi all,</span></p><p></p><p><span>Unfortunately our system recently encountered a problem during a sample run, resulting in continued pumping of A and B solvents until the lines ran dry without shutting down...</span></p><p></p><p><span>The lines have now been primed for some time to reintroduce solvents, lines B1 and B2 appear to be working well. However, although it seems all air is out of the A lines, the pump is not expelling the solvents to waste and we are unsure at what point it is being stopped?</span></p><p></p><p><span>I have tried to manually encourage it with a syringe, following 'to prime a dry binary solvent manager using a syringe' as seen in the user manual with no success.</span></p><p></p><p><span>Does anyone know where the problem may be occurring and what I can try? </span></p><p></p><p><span>Any suggestions gratefully received!</span></p><p></p><p><span>Thank you</span></p>

rune

Hi Timmy

What solvents did you have on the system when the pump ran dry ?

best regards

Rune

TimmyTrendy

Hi Rune,

Line A is 100% buffer, and line B 100% ACN.

I am anxious to clean line A out obviously but am unsure of what progress is being made as it is not reaching waste? Do you have any suggestions?

Thank you very much for your help

rune

Hi Again

My guess is that the inlet check valve on the primary pump head is blocked by precipitated buffer, and maybe also the chek valve on the accumulator pump head. I assume that you are trying to prime with pure water, but that the buffer will not dissolve since you are not getting flow through the pump.

It could also be the filter that is mounted before the check valve on the primary pump head. You can easily check this by disconecting the filter and check if solvent is the flowing freely trough the filter. If this is the case you should move to the next step :

If you have a spare inlet check valves I would change this. Try the primary pump head first and see if this helps, if not move to the accumulator pump head. If you do not have any spare check valves you could try and remove them and sonicate in water for ½ hour, to see if you can dissolve the buffer.

Good luck.

best regards

Rune

RD

To avoid prolonged operation of the pump when solvent reservoirs have run dry consider using a Low Pressure limit. Enter a value significantly lower than your operating pressure to avoid inadvertent shutdowns. For example, if I were doing gradient work and my typical operating pressure range spanned 4000 - 8000 psi, I'd feel comfortable setting the Low Pressure Limit to 2000.

The attached screen shot (from MassLynx) shows the location of this parameter.

Regards,

Rich