Hi.

I believe the gas is used to control the opening and closing of valves in the instrument. Like the old Agilent models.

Cheers

Hi Sergey,

The gas pressure is used to achieve flow of liquid by the pumps. After the pumps are calibrated, it is the gas pressure that drives the flow.

If you loose the pressure, there will be no flow of liquid or pump function.

Best,

Hediye.

Is it possible to drive up to 600 bar of liquid flow by the 6.9 bar of gas pressure? Answer from Mario looks reasonable. If you are familiar with Eksigent, could you provide some commentaries on reliability and robustness of this system. Briefly, should we buy it or not?

Hi Sergey,

I used the Eksigent with Sciex and Thermo mass spectrometers for years.

It took getting used to the gas driven flows - however, once I was comfortable and understood how it worked, I had success with very short or hardly ever, downtime with this LC. I always used it in the nano LC mode so small flow rates, not larger than 500uL. You will need a pure gas supply and I switched to a house air which was very clean. As long as there is clean gas supply, you should have long usage with no or little interruption.

Best,

Hediye.

Thank you Hediye,

What is the gas consuption by Eksigent? Is it enough to have a one gas cylinder for a weeks or you need continuously working compressor? What about pump and valves sealing, how often leaks occured?

Hi Sergey,

I do not remember the precise gas pressure but a cylinder should last you for weeks.

I do not recollect having any leaks during the time I used this system. Even when you run out of solvents in the reservoirs, you can top them up and purge. No issues.

Best,

Hediye.

Thank you for valuable information!

I have found it! It is appeared to be that Eksigent utilize pneumatic-to-hydraulic amplifier. The gain is proportional to the ratio of the pneumatic piston area to the hydraulic piston area. Thus, 100 psi incoming air pressure used to produce hydraulic pressure extending from 0 psi to 10 000 psi. The fluid pressure and flow rate is controlled by varying the pneumatic pressure. Actual flow rate for each mobile phase is determined by measuring differential pressure across calibrated capillary tubing. The internal temperature of the system is controlled and measured to correct viscosity. Flow meter is connected by feedback loop to the electro-pneumatic controller varying pneumatic pressure to maintain specified flowrate.