TCi Operator Manual
40
4.12
Chemical Testing with RTV Tabs
The RTV sealant is the sensor component most vulnerable to damage from aggressive
chemicals. RTV tabs are provided to allow potentially damaging chemicals to be tested prior to
use with the sensor, resulting in extended sensor life. See Appendix D for a complete list of
chemicals already tested.
Note: Use of a thermal chamber is required for testing at a specific temperature,
representative to the process conditions for the sensor. It is recommended to test the
chemical under the same conditions as will be used with the TCi sensor.
Note: Where chemical testing is to be done it is expected that the user is familiar with
current best safety practices and that such procedures will not be described in this
document. Review all MSDS prior to testing.
Step 1 – Set the temperature of the thermal chamber if applicable.
Leave the thermal chamber closed for two hours for it to come to equilibrium.
Step 2 – Examine each RTV tab for flaws, including pitting and air bubbles, prior to use.
Some flaws are natural due to the curing and application process.
Step 3 – Label each beaker with the chemical to be tested.
Step 4 – Seal each beaker with paraffin film.
This step may be omitted at temperatures higher than 60°C depending on chemical under test.
Step 5 – Place the beakers to be tested in the thermal chamber or fume hood if applicable.
Leave the samples in the thermal chamber or fume hood for 60 minutes.
Step 6 – Remove the samples individually from the thermal chamber.
Step 7 – Examine the test tab.
Remove the sample piece from the beaker, using tweezers if necessary. Rinse it with a small
quantity of water if necessary. Examine the sample and note observations in the table.
Step 8 – Replace the sample in the beaker.
Add a small additional amount of chemical if necessary (note uptake or evidence of absorbing
which should also be evident by the tab getting larger or puffy depending on the chemical under
test).
Step 9 – Replace the sample in the thermal chamber.
Step 10 – Repeat steps 5 to 9 for each sample at 120, 180, and 240 minutes and at 24 hours
or as required.
Step 11 – Dispose of the chemical as per its MSDS.
Step 12 – Clean the beakers.
Step 13 – Evaluate the results.
A chemical is to be designated as safe to be used with the TCi sensors if it has no effect on the
RTV test tab (effect A as noted below).
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