EPC-EFC

[smartjavad]

What are differences between EPC and EFC , the advantage and disadvantage of each?If pdf file about this question exist ,plz let me know.

[jdezeeuw]

I always understood that EPC is electronic pressure control. That means setting electronically (digital) a pressure. when running a temperature program, the pressure will remain the same, while the flow will reduce due to higher viscosity of the carrier gas being under pressure.

EFC = electronic flow control: also setting the flow digitally, but here you will see that at a constant EFC-value, the pressure will increase if a temperature programmed analysis is done.
this is beneficial as components will elute faster, and also at lower temperatures. Some detectors operate better under flow controlled conditions ( like - MS)

jaap

Restek corporation

[dblux_]

I always understood that EPC is electronic pressure control. That means setting electronically (digital) a pressure. when running a temperature program, the pressure will remain the same, while the flow will reduce due to higher viscosity of the carrier gas being under pressure.

EFC = electronic flow control: also setting the flow digitally, but here you will see that at a constant EFC-value, the pressure will increase if a temperature programmed analysis is done.
this is beneficial as components will elute faster, and also at lower temperatures. Some detectors operate better under flow controlled conditions ( like - MS)

jaap

Restek corporation

There are no standards for naming convention.
In Agilent, EPC is "electronic pneumatic control" and it can be set in constant
flow mode or constant pressure mode.

[jdezeeuw]

Correct: so is there EGC out there.. Electronic Gas Control. same as the EPC from Agilent: adresses also both modes

[dblux_]

Constant flow vs. constant pressure has already been discussed here in 2006:

viewtopic.php?f=2&t=5088&start=0

[Yama001]

I always assumed these terms are the same thing, driven by whomever (HP?) had a lock on the EPC technology when it became routine.

[GasMan]

As pointed out, some of the Agilent Electronic Pneumatic Controllers(EPC) can be set up in constantn flow mode or constant pressure mode. But there is a catch, and this depends on what type of column you are trying to control the flow in. If you are using a packed column, then you would normally use the EPC in constant flow mode. But what happens if you wish to run a capillary column in constant flow mode. The flow in capillary columns is controlled by pressure. In order to get the flow you need in the capillary column, a calculation is made to set the pressure to give this flow using the length, internal diameter of the column, temperature and viscosity of the carrier gas. This means that if you use an EPC to control constant flow, you need to set the EPC module to be in constant pressure mode, but you would set the column to be in constant flow mode.

Gasman

[CE Instruments]

lock on the EPC technology when it became routine

No not that I have ever heard, Thermo called theirs DPFC Digital Pressure and flow control. It must be 20 years since EPC started being offered. They are all the same type of thing , I am told the technology came from the electronic fuel injectors in cars