User`s manual

Lake Shore MTD Series Cryotest System User’s Manual
4-2 Operation
Lake Shore
Cryotronics
C-MTD-4-2.eps
Figure 4-2. Typical MTD with Model 1705 Horizontal Mount Cradle Assembly
CAUTION: It is important to stabilize the MTD to prevent the system from tipping over or falling.
The preferred method is the use of the optional Model 1705 Horizontal Cradle
Mount Assembly. An alternative method would be to clamp the MTD Handle/Ring
Stand Assembly to the table surface.
4. Run heated gas thru the transfer line to ensure that no moisture has accumulated in the line.
NOTE: The fuller the transfer dewar, the more an external source of gaseous helium is needed.
Less than full dewars often have a sufficient internal gas pressure to force the liquid
cryogen through the transfer line.
5. Open the transfer line valve 1 to 2 turns. Slowly insert the appropriate end of the transfer line into
the transfer dewar (until a slight gas pressure can be heard on the other end).
6. Seal storage dewar to allow pressure buildup. Actual seal depends on storage dewar used.
Standard seal is a ½-inch compression fitting which provides a gas seal and supports the
withdrawal tube.
7. Attach helium gas pressurizing hose to proper pressurizing provision on storage dewar. (If using a
pressure hat, this would be 3/8 O.D. tube soldered or welded to hat.) The procedure to hook up an
external gas source to the transfer dewar is as follows:
a. Check both Gaseous Helium and Transfer Dewar pressure gages to ensure they read zero.
If not, record the reading.
b. Connect the proper sized adapter to the transfer dewar vent line.
c. Turn on the gaseous Helium source valve.
d. Set the pressure to ≈1 psi. (Use the reading taken in step a to determine 1 psi if the gage
was not on zero.)
e. Open vent valve on transfer dewar.
f. Usually one turn on the transfer line valve is sufficient.