User`s manual

Lake Shore MTD Series Cryotest System User’s Manual
Pour-Fill Dewar F-1
APPENDIX F
POUR-FILL DEWAR
F1.0 GENERAL
This appendix will provide general information on the optional pour-fill dewar for the MTD Cryotest
System.
F2.0 DESCRIPTION
The operation of the pour-fill dewar is similar to the operation of the standard MTD-150. Internal
differences are illustrated in Figure F-1. The main chapters of this manual should be read before
using-the pour-fill system. The following differences should be noted between the systems.
1. The pour-fill dewar is primarily designed to operate at Liquid Nitrogen (LN
2
) temperature.
2. The pour-fill dewar can be operated either horizontally or with the fill port up (looking down).
If operating in a horizontal position, ensure the fill port is above the vacuum pump out valve.
3. No special helium transfer line is required. However, to ensure efficient cooling during liquid
nitrogen transfer, make sure the opening of the transfer line reaches the bottom of the reservoir.
If a funnel is used for pouring the cryogen, a length of tubing long enough to reach the bottom of
the reservoir should be added to the opening of the funnel.
NOTE: Do not let liquid cryogen cool down the base plate or vacuum leaks may develop.
NOTE: To ensure safety to users and the system, fasten the test dewar to some kind of fixture
before transferring cryogen.
4. No exhaust gas heater is used.
5. Liquid nitrogen hold time is approximately 8 hours when the system is stood upright (with the fill port
up) or 6 hours if it is in the horizontal orientation.