7
SECTION 3: OPERATION
Starting Procedures
Qualifying your Application
Welch GEMINI
™
pumps are designed for intermittent use in a variety of aqueous and organic
solvent-based applications. Proper GEMINI
™
pump operation and service life are dependent
upon use with compatible application fumes, use of a trap to minimize chemical pull-through, and
prompt cleanup to purge chemicals from the pump.
Fumes that will be compatible with your GEMINI
™
pump include neutral pH aqueous
applications as well as certain alcohols (ethanol, isopropanol ) and carboxylic acids (acetic acid).
It is important to check for pump material compatibility with potential fumes that can be drawn
off your vacuum application. Failure to follow chemical compatibility guidelines can result in
severely reduced pump service life.
The critical materials to check for chemical compatibility are the surface contact materials in your
GEMINI
™
pump. These materials are:
1. Viton
2. Polyarylamide
For handling harsh chemical fumes, Welch recommends use of pumps with PTFE-based
contact surfaces. Contact your Welch representative for information about D
F
™
,
D
F
U
™
, and Self-Cleaning Dry Vacuum Systems
™
.
3.10
3.11
