Gamry Instruments ParaCell, Operator'S Manual

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AssemblyAttaching Gas Tubing to the Cell
13
Attaching Gas Tubing to the Cell
Connect the gas flow system and add the cell electrolyte before you turn on the needle valve. Open the valve
slowly while you watch the bubbles in the cell. In addition to the needle valve, a three-way valve is useful in
purge and blanket-gas control. Three-way valves are available in both electrically switched and manual versions.
A three-way valve switches one gas stream so it flows from a single inlet to one of two outlets.
If your system includes a three-way valve for switched purge and blanket gas control, you can create a setup
with both purge and blanketing options depending on solution-fill level and your available
adapters/tubing/glassware. Check that venting is available to both purge and blanket-gas flow.
Unused Ports
More ports than are strictly necessary are available. You may use these ports to customize your system (see
later). In most experiments, however, one or more port are unused. You must keep one (top) port open for
venting when bubbling. Otherwise we recommend that you keep spare ports plugged to prevent solvent
evaporation.
Working Electrode (Sample)
Because the working (and counter) electrodes form the end seals for the ParaCell, they must be in place prior to
filling the cell with test solution.
Sample surface finish and other sample preparation are critical if you want to obtain reproducible results.
Consult the corrosion measurement literature for details about the handling of corrosion test specimens. Most of
the surface preparation techniques used for weight-loss coupons are also applicable to electrochemical test
specimens.
To mount the electrodes to the ParaCell, position them over the opening and tighten the leveling sample-
bracket down until the sample is well-sealed against the O-ring. Hand-tight should be sufficient to seal the
electrode. It may be easiest to center the working electrode(s) with the ParaCell disassembled.
Take great care to insure that the surface of your test sample is not altered prior to the test.
Avoid contacting the sample with your fingers. You may want to degrease the metal sample mounted on
the Sample Holder just prior to starting your test.
Warning:
Your gas flow system should include a needle valve to control the gas flow rate.
Make all gas tubing connections to the cell with this valve turned all the way off . Making connection with a
cell filled with electrolyte or adding electrolyte to a system when the gas flow is on can lead to severe
accidents. Excessive gas flow can damage the cell and result in a loss of electrolyte. In extreme cases, this
can represent a significant safety hazard.