Chromatography Forum

Hello everyone:
I'm trying to install an injection setup on an HP6890. I want to install 2 position Valco valves (3) but for some reason I don't want to use pneumatic actuators on them. I saw Valco sells microelectronic valves but i don't know how to connect the actuators. Should I use the 24VDC intended for pneumatic actuators or not? Has anybody has this type of actuators on a GC? Any information will be highly appreciated.
Thanks

The 24 Volts internal supply can only supply 13 Watts of power, and was designed to operate solenoid valves, not control electric valves. Before you go ahead with your plan, you should determine the following.

1. How are you going to mount the valves? Do they need to be heated?

2. Are you going to use a temperature program. If yes, it is not a good idea to mount the valves inside the oven.

3. Will you use the 110 Volt electric drive from Valco or the 24 Volt version.

Both versions of the 'electric' valves need two contact closures to operate, one to turn on and one to turn off. However, it is possible to program at least the micro-electric actuator, so that only one contact is needed. To do this you will also need to order a RS232 cable from Valco so that you can program the module.

Also bear in mind that the electric actuators do NOT like heat. What do you have against air actuation?

If you wish to control 3 valves, you will have extra work. The 6890 only has two relay contacts, controlled by valves 7 and 8. You would need a 24 Volt relay to control a third valve.

Gasman

The last time I needed to do something like this, I contacted Wasson-ECE and they mounted the valves, actuators, relays in a side mounted box for us. All I had to do was run the cable over to the other side of the GC, add air (yes - they're air actuated), and cut the carrier line. You might want to contact them, it may end up being as cheap as buying everything individually. (I have no financial arrangment with them).

Thanks for the plug larkl.

aamorin,

GasMan covered very well the important things to consider when doing this. If you're interested in having the configuration done by Wasson-ECE, please give me a call (970-221-9179) or send an e-mail with the specifics of what you're trying to accomplish (sales@wasson-ece.com).

- Brice

Thank you guys!!
The application is simpler that it looks like, the valves will be located on top of the GC, not into the oven, and the idea is to have a system to inject 1 liq sample into 2 cols (2x internal loop valves) and the same for gas samples when needed (1x 10 port valve). I got nothing against pneumatics actuators, but my boss does, so we trying to see if it's feasible or not. I particulary preffer to go 24V but it'll be no problem if we have to use 110V.