You can control the sample atmosphere during DSC experiments by connecting purge gases to the system. The DSC instruments are all equipped with a mass flow controller (MFC) to control the flow rate of the gas. Up to two different gases may be connected to the instrument to facilitate gas switching.
Select from the following topics for more information:
CAUTION: Do not use any liquid in the purge lines.
Follow these instructions to connect the purge lines. Refer to the figure below to locate the purge lines.
Back to top
Locate the Gas 1 port. The Gas 1 port is used to purge the sample area.
Locate the Gas 2 port. The Gas 2 port is also used to purge the sample area and is used when a purge gas other than Gas 1 is desired or when gas switching during an experiment is needed.
Connect the primary gas line to the Gas 1 port using 1/8-inch O.D. tubing. Teflon® TFE tubing is recommended and is supplied in the instrument shipping accessory kit. If desired, connect a secondary gas to the Gas 2 port. The flow rate is controlled through settings chosen using the instrument control software.
Make sure that the pressure of your purge gas source is regulated between 100 to 140 kPa gauge (15 to 20 psig).
Specify the purge gases connected to the gas ports on the Instrument Preferences/MFC Purge Page.
Set the flow rate for your experiments on the Notes Page.
NOTE: If you are using laboratory purge, rather than bottled purge, it is highly recommended that you install an external drier and a five-Ám filter.
CAUTION: Corrosive gases cannot be used with this instrument. The MFC is not designed to work with corrosive gases.
WARNING: Use of an explosive gas as a purge gas is dangerous and is not recommended for this instrument. For a list of the purge gases that can be used with the DSC instrument, see Recommended Purge Gases and Flow Rates.
Teflon« is a registered trademark of E. I. du Pont de Nemours and Company.
Back to top
A base purge is required when the Quench Cooler, Refrigerated Cooling System (RCS), or the Liquid Nitrogen Cooling System (LNCS) are used.
Locate the Base Purge port. Refer to the figure below to locate the ports.
Make sure that the pressure of your gas source is regulated between 100 and 140 kPa gauge (15 and 20 psig). Dry nitrogen is the recommended gas.
NOTE: For Subambient Operation: Since the base purge gas will be exposed to temperatures below ambient, the gas should be moisture-free. Nitrogen gas of 99.999% purity is recommended for use as a base purge gas.
Connect the gas line to the Base Purge port using 1/8-inch O.D. tubing. Teflon TFE tubing is recommended. An orifice in the instrument will automatically regulate the flow rate (300 to 350 mL/minute) for proper operation.
Back to top