Allied Telesis 6870 User Manual
15 Liberty St., Metuchen NJ 08840
1-800-LAB-SPEX (1-800-522-7739) ext 465
6870
FREEZER/MILL
®
OPERATING MANUAL
This manual is part number 85018
TABLE OF CONTENTS
SECTION DESCRIPTION PAGE
1.0 Introduction..................................................................................................................................3
2.0 Specifications...............................................................................................................................4
3.0 Unpacking....................................................................................................................................5
4.0 Setting Up ....................................................................................................................................6
5.0 Touch Screen Displays................................................................................................................9
6.0 Practical Operation....................................................................................................................14
6.1 Adding Liquid Nitrogen Coolant…………………………………………………….14
6.2 Loading Samples into Freezer/Mill Vials……………………………………………15
6.3 Removing, Opening, Emptying, and Cleaning Freezer/Mill Vials…………………..17
6.4 Checking Liquid Nitrogen Level…………………………………………………….20
6.5 6820 Auto-Fill System………………………………………………………………20
6.6 6814 AutoExtractor………………………………………………………………….21
6.7 Maintenance…………………………………………………………………………21
7.0 Warranty and Service................................................................................................................21
8.0 Trouble-Shooting Guide............................................................................................................23
Page 2 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 crosssample 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 -195.8o 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
Page 3 of 25 SPEX SamplePrep LLC 9.24.07
SECTION 2.0: 6870 FREEZER/MILL SPECIFICATIONS
Type of mill: cryogenic impact mill
Grinding mechanism: steel impactor driven by dual electromagnets
Coolant: liquid nitrogen
Weight (empty, without vial or coolant): approx. 44 lbs. (20 Kg)
Grinding Vials: one 6801 Large Vial, one Mid-Size Vial (6871, 6881, 6885), or one 6753
Microvial set, also one to four Small Vials (6751, 6751/52, 6761, 6771).
Typical Sample Capacity:
Small Vials: actual volume with impactor, approx. 25 ml. Typical sample weights: 2
grams for biological samples, 1 gram for polymers. Effective capacity for a given
sample is determined by trials. Overfilling a vial greatly reduces its efficiency.
6753 Microvial Set: 100 - 500 mg per individual 6753V Microvial, depending on
sample.
Mid-Size Vials have up to 5 times the sample capacity of Small Vials, and Large Vials
about twice the sample capacity of Mid-Size Vials.
Actual performance of any vial/sample combination depends on sample properties,
cooling time, grinding time, desired outcome, etc.
Typical liquid nitrogen consumption:
10-15 liters for initial cool-down and filling of the tub.
4-6 liters for each hour of operation
Actual LN consumption can vary.
Electrical specifications: CE Approved, available in 115V 60HZ or 230V 50HZ.
Cord: 115V 60HZ version, 3-prong grounded plug supplied.
230V 50HZ version, 2-prong European plug supplied.
Operator is responsible for supplying alternate line cord/plug if required.
Fuses: Two 5-amp slow-blow fuses in AC Input module.
25-amp slow-blow fuse on driver board
Dimensions
CE Compliance and Certification
Directives for Industrial, Scientific, and Medical Equipment Emission, and Generic Light Industrial
Immunity.
Safety Features:
NOTE: Liquid nitrogen level should be visually checked during extended runs as well as
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.
: 20½ in. (52 cm) x 21½ in. (55 cm) x 18 in. (46 cm)
: The 6870 Freezer/Mill has been tested for compliance with CE
Lid Interlock prevents mill from running if lid is not latched shut.
Liquid nitrogen sensor shuts down mill if liquid nitrogen level is too low.
Page 4 of 25 SPEX SamplePrep LLC 9.24.07
SECTION 3.0: UNPACKING
Inspect the exterior of the packing box and report any visible damage to the carrier. Remove all
packing documents from the exterior of the box, and save them for your records. Open the top of
the shipping box. Remove the packing material and accessories, and gently remove the
Freezer/Mill. Visually check the mill for any damage that may have occurred during shipping.
Unlatch the lid and inspect the interior of the tub, ensuring that it is free of any packing material.
Check the packing list to see that there are no parts missing, and inspect the accessories. If
everything seems to be in proper order, we recommend you store the packaging materials, in
case there you ever need to return the unit for warranty service or repair.
Grinding vials must be purchased separately and are available in three sizes: large, mid-size, and
small. Each new 6870 Freezer/Mill includes an Acccessory Package to match your choice of
vials, either the 6870L for large vials or the 6870S for small vials. Both include an extractor for
removing end plugs from cold vials, and a vial rack; the 6870S also includes an adapter for
running up to four vials in the 6870. A 6870M Accessory Package is available for mid-size
vials, but must be used in conjunction with the 6870L. The full range of grinding vials and
accessories for the 6870 Freezer/Mill is described in our catalog (Handbook of Sample
Preparation and Handling) and on our website (www.spexcsp.com).
6870 FREEZER/MILL, FRONT VIEW
Page 5 of 25 SPEX SamplePrep LLC 9.24.07
6870 FREEZER/MILL, BACK VIEW
SECTION 4: SETTING UP
The 6870 Freezer/Mill weighs 44 pounds (20 Kg) empty. The lid opens from the front and the
lid latch is in the center. The AC Input module is on the back of the cabinet, and includes the
power switch and fuse tray. The fuse tray can be opened with small screwdriver or knife-blade.
Also on the back of the cabinet is the vent from the liquid nitrogen tub. There are gas cylinders
on both sides of the cabinet to control the movement of the lid. The control panel is on top of the
lid, and can be detached for remote operation. It is connected to the lid by an RJ45 (“Ethernet”)
cord. On the back of the lid is a USB port to let you link the 6870 Freezer/Mill to a PC or LIMS
system.
4.1 Electrical Hookup
Plug the electrical cord into the inlet on the back of the Freezer/Mill cabinet, and then into a
standard 3-prong grounded electrical outlet. We recommend a fused 20-amp circuit for the
115V/60 HZ version. If you have the 230V/50HZ version of the mill, make sure the cord and
plug conform to local electrical codes; we furnish the 230V/50HZ 6750 Freezer/Mill with a
standard European 2-prong plug with cord.
4.2 Power Switch and Control Panel
Electric power to the Freezer/Mill is controlled by the rocker switch on the inlet module. It is
marked with two numerical symbols, zero (0) for “off” and one (I) for “on.” Press the one (I)
side of the switch to turn the power on, or press the zero (0) side of the switch to turn the power
off. When power to the mill is on, the control panel display will light up.
Page 6 of 25 SPEX SamplePrep LLC 9.24.07
The control panel is a touch-screen, activated by a stylus. The Freezer/Mill is programmed and
operated through this control panel, whose successive screens are described and illustrated in
Section 5, starting on page 8. Programmable parameters include pre-cooling time, grinding time,
cooling time between grinding periods, the number of grinding periods, and the rate of grinding.
The control display also warns if the lid is not fully closed, or if there is not enough liquid
nitrogen in the tub.
4.3 Lid and Lid Latch, Coil Assembly and Coil Gate, LN Sensor
The lid of the 6870 Freezer/Mill supports the coil (dual electromagnet assembly) and coil
housing. To open the lid, hold the lid down with one hand, and with the other pull the upper end
of the latch toward you. The lower end of the latch should disengage from the cabinet. Release
the lid and it should be pushed up by the gas cylinders, which also keep the lid raised when open.
The lid must be open to put vials in the coil and take them out. Liquid nitrogen (LN) is added
with the lid open, unless the 6870 is equipped with the 6820 Auto-Fill System.
The lid must be shut and latched for the Freezer/Mill to run. Push the lid down, hold it down
while engaging the latch, then lock the latch by pushing its top end toward the cabinet.
The circular hole on the right side of the coil housing is where to insert a vial for grinding. The
coil gate keeps the vial or vials in place during grinding, but must be lowered to insert or remove
vials. The rectangular space toward the top of the coil housing is for pre-cooling loaded vials.
(Do not run the 6870 Freezer/Mill without a loaded vial in the coil.)
The coil gate holds the vial or vials in the coil during grinding. To lock a vial in place, loosen
(unscrew) the coil gate handle a turn or two, and position it so the handle passes through the slot
in the coil gate when the gate is raised. Tighten the coil gate handle against the gate, so the gate
contacts the vial snugly, but do not overtighten the gate as this can crack the plastic center
section of the vial. When the coil gate handle is properly tightened, fold it down to lock the gate
during grinding. Always use the proper Adapters for Mid-Size and Small vials (see 4.4), and
always wear gloves when touching a chilled vial or any part of the chilled coil housing!
The LN sensor is behind a shield on the back wall of the LN tub. If there is not enough liquid
nitrogen in the tub to start the mill, when RUN is touched the STATUS screen (p. 10) will display
STATUS: LOW LN LEVEL. If the LN runs low during a grinding program the same message
will appear and the program will stop. To continue running, fill the tub with liquid nitrogen to
the mark. When RUN is pressed, the grinding program will start over.
To keep a run from being interrupted by the liquid nitrogen (LN) sensor, the LN level should
be visually checked from time to time during extended runs, as well as before every run. The
6870 Freezer/Mill can run low on LN during extended runs, so should be checked after each
30 minutes of grinding time, and the LN topped off if necessary. The Freezer/Mill warranty
does not cover damage to the coil caused by operating the mill with little or no liquid nitrogen.
Page 7 of 25 SPEX SamplePrep LLC 9.24.07
4.4 Grinding Vial Sizes, Adapters, and Vial Openers.
Large vials (6801, 6871) are run one at a time in the 6870 Freezer/Mill, without any adapter.
Large vials are opened by the 6804 Extractor/Vial Opener, which is part of the 6870L Accessory
Package.
Mid-Size vials (6881, 6883, 6885) are run one at a time, but the 6886 Mid-Size Adapter must be
placed in the coil first, to center and align any Mid-Size vial. Mid-Size vials can be opened by
the 6804 Extractor/Vial Opener, but only by installing the 6884 Mid-Size Vial Adapter for the
6804. The 6884 and 6886 Adapters comprise the 6870M Accessory Package.
Most Small vials (6751, 6761, 6771) can be run one, two, three, or four at a time in the 6870
Freezer/Mill. However, they must be used in conjunction with the 6806 Multi-Vial Adapter, an
X-shaped insert for the coil. The 6806 Adapter keeps the vials parallel to each other and the coil,
so each impactor moves back and forth in line with the magnetic field. Also, if a small vial were
to be positioned diagonally inside the coil, the gate could not be properly tightened against the
vial, and an end plug might work its way out of the vial during grinding. When running Small
vials, make sure the coil gate contacts the end plug of every vial. If the gate needs adjustment to
do this, the bottom or pivot end of the gate can be moved toward or away from the coil housing
by turning the gate clockwise or counterclockwise on its mounting bolt.
Unlike other Small vials, the 6753 Microvial Set is run one at a time with the 6806 Adapter.
Each 6753 set includes three 6753V Microvials. If more than one 6753 Microvial Set is placed
in a 6870 Freezer/Mill, some of the individual Microvials will be shielded from the magnetic
field, and grinding in those vials can be ineffective.
Page 8 of 25 SPEX SamplePrep LLC 9.24.07
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