Filter
Top Products
Page 3 of 25 SPEX SamplePrep LLC 9.24.07
SECTION 1.0: INTRODUCTION
SPEX SamplePrep Freezer/Mills are cryogenic laboratory mills that cool samples to cryogenic
temperatures, and pulverize them by magnetically shuttling a steel impactor back and forth
against two stationary end plugs. Since the vial is closed, the integrity of its contents is
maintained: hazardous or critical samples are easily controlled, cleanup is simplified, and cross-
sample contamination is eliminated. Because the vial is immersed in liquid nitrogen throughout
the grinding cycle, the sample is kept at cryogenic temperatures and its key aspects preserved.
These features have made SPEX SamplePrep Freezer/Mills the most effective cryogenic mills in
the world. They are the “mills of last resort” for many normally ungrindable samples, or samples
whose composition or structure is altered by the heat generated by conventional grinding.
Before operating the 6870 Freezer/Mill, familiarize yourself with these instructions. The
Freezer/Mill is different in its principles and operation from any other laboratory mill. If
you’re familiar with the mill and want to proceed directly to grinding, Section 6.0
(PRACTICAL OPERATION) on p.14 can serve as a general review of the actual operation of
the mill. We suggest unpacking the mill, then going over its various features with these
instructions in hand before attempting to add liquid nitrogen or grind a sample.
OPERATING CONDITIONS: Do not set up the 6870 Freezer/Mill in an insulated or confined
space. The Freezer/Mill should be run on an open countertop, in ambient air. If the entire mill is
chilled during operation, components like the gas cylinders can fail. This damage is not covered
by the Freezer/Mill warranty.
VERY IMPORTANT: Liquid nitrogen not only makes samples brittle through severe chilling,
making them “grindable,” but also cools the magnetic coil which powers the 6870 Freezer/Mill.
If the mill is operated without liquid nitrogen for a period of about one minute, the coil will
become very hot and may sustain permanent damage. The 6870 Freezer/Mill has a liquid
nitrogen sensor that should shut down the mill when the liquid nitrogen gets too low to cool the
coil. Nevertheless the nitrogen level should be visually checked during extended runs as well as
topped off before every run. The Freezer/Mill warranty does not cover damage to the coil
caused by operating the mill with little or no liquid nitrogen.
SAFETY NOTES:
1) Liquid Nitrogen can be hazardous. Its boiling point is -195.8
o
C. When working with liquid
nitrogen directly or indirectly, you must wear cryogenic gloves to protect your hands. Be careful
not to splash liquid nitrogen on clothes or unprotected skin. Always use cryogenic gloves when
handling very cold objects or materials: sample vials, the nitrogen tank valve or hose, chilled
Freezer/Mill components, etc. We also recommend safety goggles to protect your eyes.
2) Do not attempt to operate the 6870 Freezer/Mill without liquid nitrogen