Worthington LD Series User manual

LD Series
Extended Time Series
Liquid Nitrogen Dewars
Safety
Before using any cryogenic refrigerator, read the Handle
with Care booklet provided with the unit. It details safety
precautions that must be understood before using the
equipment. If a replacement booklet is needed, order
publication Handle with Care from your supplier. Following
are a few of the safety precautions described in the Handle
with Care booklet. Please be sure to read the entire booklet.
Store and use these containers only in well
ventilated areas. In a confined area, nitrogen gas from
these units may cause suffocation by displacing air needed
for breathing. Install a suitable oxygen monitor.
Do not touch liquid or cold metal surfaces with
your bare skin. The liquid nitrogen refrigerant in these
containers is extremely cold: -196°C (-320°F). Exposure of
skin or eyes to liquid, cold gas or frosted parts could result in a severe frostbite-like injury. Because of the extremely low
temperature, a face shield and gloves must be worn when transferring liquid nitrogen and material into or out of these
containers.
Use only the necktube core supplied with this unit or a listed replacement part. A tight fitting plug or
stopper will cause a pressure increase in the container that may damage the container and/or cause personal injury.
Dispose of liquid nitrogen only in areas specifically designed for that purpose. Disposal of liquid
nitrogen should be done outdoors in a safe place. Pour the liquid slowly on gravel or bare earth
where it can evaporate without causing damage.
Operation
Filling: Adding liquid nitrogen to a warm container may cause splashing and will generate a significant volume of
nitrogen gas as cold liquid contacts warm Dewar surfaces. Add liquid slowly to minimize these effects. Be sure there is
adequate ventilation. Keep your head clear of the heavy volume of vapor that may be produced. It is extremely cold
and could cause personal injury.
WARNING
DO NOT OVERFILL. Over-filling may result in personal injury due to liquid spillage.

Determining Liquid Level
Liquid level must be checked at regular intervals – refrigeration depends on the presence of liquid nitrogen. The liquid
level in the container can be determined with a dipstick. Insert the dipstick vertically into the container so that it rests on
the canister indexing device on the bottom of the unit. After 5 to 10 seconds, withdraw the dipstick and wave it back
and forth in the air. A frost line will form representing the depth of liquid in the container. The frost line will typically be
u-shaped; read the bottom of the u-shaped line to determine liquid level.
WARNING
Never use a hollow rod or tube as a measuring rod. When a warm
tube is inserted into liquid nitrogen, liquid will exit from the top of the
tube and may cause personal injury.
The liquid level chart shows volume of liquid nitrogen vs. depth for
LD Series Dewars. These values are approximate and are based on
standard conditions.
Routine Care & Maintenance
If ice build-up interferes with normal operation of the Dewar, the unit should be emptied and thawed. To thaw the unit,
pour out the liquid, disposing of it out-of-doors where the cold liquid will not damage driveways and other surfaces.
Warm the Dewar by purging it with air even after the Dewar has warmed to room temperature to evaporate any
collected moisture. When the Dewar is ice-free and dry, rinse the inner vessel with household bleach. Wash the inner
vessel with a 40 to 1 ratio of water to laundry detergent solution. Rinse and dry inside and out thoroughly before
placing the Dewar back into service. Do not use sharp instruments to chip ice; permanent damage to the Dewar could
result. DO NOT attempt to fasten any device to the Dewar. Welding, brazing, or piercing of the Dewar in any manner
will cause permanent damage and void the limited warranty.
Check liquid levels regularly. If high evaporation rates are apparent under normal operating conditions, the
Dewar may be losing its vacuum. Sweating and the formation of frost or ice on the outer casing are indications that the
Dewar may be losing its vacuum. Sweating or freezing of the outside casing are definite indications that the insulation
integrity may have been compromised.
If these conditions persist, contact your supplier or Worthington’s Customer Service Department at 844-273-7517 /
[phone] or e-mail us at [e-mail] for information on how to conduct a
normal evaporation rate (NER) test in the field.
MODEL LITERS/INCH LITERS/CM
LD4 0.40 0.16
LD5 0.43 0.17
LD10 0.76 0.30
LD25 1.56 0.62
LD35/LD50 2.67 1.05
CLASSIC-25 0.60 0.23
LD Series

LD Series
LIQUID WITHDRAWAL DEVICE P/N MODEL
For convenient pressure-transfer of liquid nitrogen from the LD25, LD35, and LD50 Dewar.
Designed specifically for the LD Series Dewar, this accessory contains the appropriate
safety relief devices, pressure gauge, and means of refilling the Dewar with the Liquid
Withdrawal Device installed.
369383 (7psig) LD25, LD35, LD50
TIPPING STAND P/N MODEL
For dispensing liquid from the LD25. This easy-to-use stand supports the weight of
the Dewar and allows convenient, safe pouring of liquid. Wheels add mobility and
additional handling ease.
366582 LD25
ROLLER BASE P/N MODEL
With ball bearing swivel casters to provide convenience and portability within a working
area where frequent container movement is necessary or desirable.
366742 LD25
366577 CLASSIC-25
366783 LD35, LD50
LIQUID LEVEL MEASURING ROD P/N MODEL
Graduated in both inches and centimeters. This accessory is inserted into the cryogenic
refrigerant to determine actual liquid level. 378150 All Units
LIQUID NITROGEN DIPPER P/N MODEL
For dispensing small quantities of liquid nitrogen. 366744 All Units
Accessories
The following accessories are available for LD Series Dewars:
Ordering Information
Order all replacement parts and accessories from your local distributor. Please include the model number of your Dewar,
part number, quantity, and description of each part requested. For more information or to find the name of your local
distributor, contact Worthington Industries at the phone number or email listed below.
REPLACEMENT PARTS
DEWARS LD4 5LD LD10 CLASSIC-25 LD25 LD35 LD50
Necktube Core 366554 366564 366569 366579 366588 366609 366609
7950-8346
©2019 Worthington Industries. All rights reserved. 372423 – 10/19
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