TA Instruments AR 2000, Operator'S Manual

Page: 102 / 144

AR 2000 Operator’s Manual
102
Running Experiments in Self-Pressurization Mode
After the manifold is installed, all fittings have been tightened, and the sample has been loaded, follow these
steps to run an experiment in the self-pressurization mode.
1. Make sure the three-way valve on the manifold is set to the OFF position (horizontal).
NOTE: The secondary pressure relief valve on the Pressure Gauge Port should only be
opened if the primary pressure relief passage becomes clogged. If this valve was opened,
make sure it is closed.
2. Set the testing temperature from the software.
3. Program the test procedure.
4. Run the experiment.
5. After running the experiment, depressurize the cell by following these steps:
a. Ensure the the pressure cell is isolated from the high pressure source.
b. When the experiment is complete, the temperature should be set back to 25°C (ambient temperature)
before attempting to relieve the pressure in the cell.
c. Once the cell has cooled, set the three-way valve on the manifold to the "Pressure Relief" position
(arrow pointing upward). Note that the pressure may reduce very slowly, due to the snubbers in the
manifold.
NOTE: There are two snubbers in the manifold, one of which is located on the cell itself and
the other in the vent line, as described earlier in this chapter. These are used to slow the
build and relief of pressure in or from the cell. The snubbers may become clogged with sample,
preventing the cell pressure from being properly relieved (this problem is more likely to occur
when external pressurization is being used). You must maintain the cleanliness of the
snubbers, ensuring that gas can pass through them. You can verify that they are operating
properly by pressurizing and depressurizing the cell without a sample. If there is any doubt
concerning the cleanliness or operation of the snubbers, they should be replaced.
NOTE: The pressure relief valve on the cell’s Pressure Gauge Port can also be used to relieve
the pressure in the cell. This should only be done if the three-way valve on the manifold
cannot be used, if, for example, the snubbers have become blocked. The cell should also be
at room temperature before using this valve, and appropriate gloves and safety glasses
should be worn.
The pressure gauge located on the Pressure Gauge Port and the pressure gauge on the manifold can be used
to help verify that the snubbers are not clogged. After relieving the pressure in the cell using the manifold
and three-way valve, the two gauges should read zero (0) pressure. If the snubbers are clogged, the pressure
gauge in the Pressure Gauge Port may still register pressure. If that condition occurs, use the relief valve on
the Pressure Gauge Port to release pressure from the cell.