Cryomech LNP-40 User manual

Model LNP-40
Liquid Nitrogen Plant
INSTALLATION, OPERATION and
ROUTINE MAINTENANCE MANUAL

The information contained in this document is believed to be accurate and reliable as of
the time of its publication. However, Cryomech, Inc. cannot accept any responsibility
(financial or otherwise) that may result from the use or misuse of the information
contained in this document. Except as expressly contained in this document, there are no
other warranties granted or extended by the manufacturer.
Cryomech, Inc. reserves the right to add, change, modify or delete any or all information
contained herein without prior written notice. Revisions to this document may be issued
at the time such changes and/or deletions occur.
Any duplication of this manual or any of its parts without expressed written permission
from Cryomech, Inc. is expressly prohibited.
Correspondence concerning this document should be forwarded to:
Customer Service Department
Cryomech, Inc.
113 Falso Drive
Syracuse, NY 13211 USA
Telephone [phone]
FAX: [phone]
Email: [e-mail]
Website: www.cryomech.com

Contents
Section 1
Overview
Section 2
Warranty
Section 3
Safety
Section 4
Inspection and Unpacking
Section 5
Specifications
Section 6
Installation
Section 7
Operation
Section 8
Routine Maintenance
Appendix
Spray Lubricant Instructions

1.1-N
Section 1
Overview

Overview
1-1
Section 1: Overview
This section provides an overview discussion of Cryomech Liquid Nitrogen Plants. It also
provides an overview of this manual, including the organization, basic definitions of terms
used and expansion of acronyms used in the manual.
1.1 Liquid nitrogen plant
1.1.1 General description
Cryomech’s Liquid Nitrogen Plants (LNP) are designed to generate liquid nitrogen (LN2)
from atmospheric air. The LN2is produced and stored in the system’s dewar. A standard
liquid nitrogen plant consists of an air compressor, a compressed air filter bank, a
nitrogen generator, a cryorefrigerator and a dewar.
The air compressor and compressed air filter bank supply clean, dry compressed air to
the nitrogen generator. The nitrogen generator uses the compressed air to produce
gaseous nitrogen.
The gaseous nitrogen enters the dewar where it is liquefied and stored. A Cryomech
Cryorefrigerator is used to liquefy the nitrogen. The liquid nitrogen plant is fully automatic
and will shut down the cryorefrigerator when the dewar is full. Liquid nitrogen can be
extracted from the dewar whether or not the cryorefrigerator is operating.
The operation of the Cryomech Cryorefrigerator is based on a closed-loop helium
expansion cycle. A complete system consists of two major components: one is the helium
compressor package, which compresses refrigerant and removes heat from the system;
the other is the cold head, which takes refrigerant through one or more additional
expansion cycles to cool it down to cryogenic temperatures. The refrigerant gas used in
the Cryomech Cryorefrigerator is 99.999% pure helium. Flexible stainless steel lines
called helium flex lines carry compressed helium from the compressor package to the
cold head and carry low-pressure helium back.
The compressor package works as follows. An oil-lubricated compressor compresses the
pure low-pressure helium that is returned from the cold head. The heat of compression is
removed via a heat exchanger, and the oil from the compression process is removed in a
series of oil separators and filters. The compressed helium is then fed to the cold head
via the high-pressure helium flex line.
In the cold head, adiabatic expansion of the helium and further heat removal allows
cooling to cryogenic temperatures. The low-pressure helium then returns to the
compressor package via the low-pressure helium flex line.
1.1.2 Features and benefits of Cryomech Liquid Nitrogen Plants
Cryomech’s Liquid Nitrogen Plants have been carefully designed and manufactured to
provide years of trouble free service.
Primary features
•Easily installed
•Fully automatic operation
•N
2gas produced with advanced membrane technology

Overview
1-2
•Easily serviced in the field
Primary benefits
•Requires only electrical power
•Does not require full time, trained operator
•High reliability
•Low cost of operation and maintenance
1.2 Cryomech Liquid Nitrogen Plant Manual
This manual covers the complete Liquid Nitrogen Plant that consists of a dewar with an
attached cold head, a helium compressor package, a dewar cord, a set of helium flex
lines, an N2generator/filter bank panel, a nitrogen flex line, and an air compressor.
It is important that you review this manual carefully before beginning the installation
process.
1.2.1 Organization of the manual
The main body of the manual provides a detailed discussion of everything you will need
in order to install and operate the Cryomech Liquid Nitrogen Plant and to perform routine
maintenance. It is divided into 8 sections. Illustrations accompany the discussion as
needed for clarification. Additional information will be in the appendix.
Numbered lists labeled with 1), 2), etc and lettered lists labeled with a., b., etc. are used
for sequential actions that must be performed in the order listed. Lists for which order is
not important are bulleted, using solid or hollow bullets.
The manual contains essential information for the safe and effective operation of your
Cryomech Liquid Nitrogen Plant. Sections 2 and 3 clearly lay out all safety precautions
you should take and also explain the ways in which you might inadvertently void your
warranty by doing something that would damage the system.
Sections 4 through 8 provide complete step-by-step instructions on the handling of your
Cryomech Liquid Nitrogen Plant, from inspection of the packing crate through routine
maintenance. Each safety precaution is also shown in these sections in every place
where observing the caution or warning is important.
•Section 1: Overview (including definitions and acronyms)
•Section 2: Warranty
•Section 3: Safety
•Section 4: Inspection and unpacking
•Section 5: Specifications
•Section 6: Installation
•Section 7: Operation
•Section 8: Routine maintenance
•Appendix: Additional information

Overview
1-3
1.3 Glossary
1.3.1 Definitions
The terms defined below are used with precision in the manual. For example, distinction
is made between the (helium compressor) package, and the (helium compressor)
module.
The terms are in alphabetical order, and italicized terms within the definitions are terms
that are also defined in this section.
Aeroquip®Couplings:
The term "Aeroquip®couplings" is used generically to describe the self-sealing fittings
that connect components e.g. that connect helium flex lines to the helium compressor
package and helium flex lines to the cold head.
Air Compressor:
The standard air compressor, if supplied by Cryomech, is a two stage, pressure
lubricated compressor with a horizontal receiving tank. A pressure switch automatically
maintains the compressed air pressure required by the nitrogen generator.
Category II Installation:
Category II refers to the potential for transient over-voltage conditions in the mains power
connection to the equipment. See IEC 664, Sub-clause 5.6 for further details.
Closed Loop System:
This refers to a cryogenic system that has no helium loss because the helium is cycled
through a closed loop. The advantage of such a system is that there is no need to add
helium.
Cold Head:
The cold head is an expansion device, which is capable of reaching cryogenic
temperatures. The cold head is mounted to the top of the dewar.
Cold Head Heat Exchanger:
The heat exchanger on the cold head provides cooling at cryogenic temperatures by
transferring heat to the helium within the system.
Compressed Air Filter Bank:
A series of four filters are used to purify the compressed air before it enters the nitrogen
generator. The first two filters are designed to remove water and any bulk oil carry-over
from the compressed air stream. The third filter contains an activated carbon element to
further eliminate any hydrocarbon contaminants in aerosol form. The fourth filter traps
any carbon dust that exits the activated carbon filter.
Cryogenic Temperatures:
Temperatures lower than 120K or -153°C.
Cryorefrigerator (Cryocooler):
A cryorefrigerator is a cryogenic refrigeration system based upon a closed loop helium
expansion cycle. It consists of a helium compressor package, helium flex lines and a cold
head (expansion device).

Overview
1-4
Dewar:
The dewar is a stainless steel, vacuum jacketed container built for the purpose of storing
liquid nitrogen with minimal boil off. The dewar is sealed from the atmosphere so that
only nitrogen gas flowing from the N2generator can enter it. The cold head, attached to
the top of the dewar, liquefies the nitrogen gas inside the dewar.
Dewar Cord:
The dewar cord is pre-wired and fitted with electrical connectors on each end that attach
to the dewar and helium compressor package. The dewar cord provides electrical power
from the helium compressor package to the dewar.
Extraction Line:
Liquid nitrogen is extracted from the dewar through the extraction line. The extraction line
is a vacuum jacketed, flexible, stainless steel hose. A vacuum jacketed, manually
operated valve is attached to the top of the extraction line. Liquid nitrogen is withdrawn
from the dewar by opening the valve. The positive pressure inside the dewar pushes the
liquid nitrogen out of the dewar.
Gifford-McMahon (GM) Cryorefrigerator:
A Gifford-McMahon cryorefrigerator is a cryorefrigerator in which the cold head expands
the helium using a displacer or piston.
Helium Compressor Module:
Located inside the helium compressor package, the helium compressor module is an oil-
lubricated commercial compressor that compresses low-pressure helium to the
necessary high pressure.
Helium Compressor Package:
The helium compressor package houses the helium compressor module and all other
components that cool and purify helium and that provide system safety control. The
helium compressor package compresses the low-pressure helium returning from the cold
head and provides clean high-pressure helium to the cold head.
Helium Flex Lines:
The helium flex lines are corrugated stainless steel hoses that transport helium between
the helium compressor package and the cold head.
Level Indicator/Switch:
The level indicator/switch, mounted to the dewar, monitors and regulates the amount of
liquid nitrogen in the dewar. The level indicator/switch is preset to shut down the system
when the dewar is full. The user can set the liquid nitrogen level, at which the system will
automatically restart.
Nitrogen Flex Line:
The nitrogen flex line is a corrugated stainless steel hoses that carries nitrogen from the
N2generator to the dewar. This line only applies to Liquid Nitrogen Plant models.
N2Generator:
The N2 (nitrogen) generator uses membrane technology to produce nitrogen gas from
compressed air. The nitrogen passes through the membrane while the other constituents
of air are separated out and returned to the atmosphere through a vent in the generator.
Pollution Degree 2:
Pollution degree 2 refers to the extent to which the local environmental conditions could
affect the electrical safety of the system. See EN 61010 or UL 61010A for further details.

Overview
1-5
Pulse Tube Cryorefrigerator:
A pulse tube cryorefrigerator is a cryorefrigerator in which the cold head expands the
helium using a pulse tube instead of a displacer or piston.
System:
The term "system" is used as a synonym for the liquid nitrogen plant. It consists of a
dewar with an attached cold head, a helium compressor package, a dewar cord, a set of
helium flex lines, an N2generator/filter bank panel, a nitrogen flex line, and an air
compressor.
1.3.2 Acronyms
The following acronyms are used in the text and provided here for convenient lookup.
FPT Female Pipe Thread
GPM Gallons per Minute
LN2Liquid Nitrogen
LPM Liters per Minute
MPT Male Pipe Thread
N2Nitrogen
OFHC Oxygen-Free High Conductivity (describes a form of Copper)
PSIG Pounds per Square Inch Gauge
1.4 Cryomech Contact Information
Cryomech,Inc.
113 Falso Drive
Syracuse, NY 13211
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.cryomech.com
13Feb07

2.1-N
Section 2
Warranty

Warranty
2-1
Section 2: Warranty
2.1 Statement of warranty
Provided that the customer installs, operates and maintains this liquid nitrogen plant
according to the specifications and procedures set forth in this manual, Cryomech, Inc.
extends a warranty on all parts and workmanship for a period of three (3) years or 8,000
operating hours, whichever comes first. This warranty covers all non-user serviceable
components of the helium compressor package, the cold head, the helium flex lines, the
dewar, the nitrogen flex line and the compressed air filter bank. The warranty does not
cover user-serviceable parts.
Provided that the customer installs, operates and maintains the air compressor according
to the specifications and procedures set forth in the air compressor manufacturer’s
manual, Cryomech, Inc. extends a warranty on all parts and workmanship for a period of
one (1) year from the date of shipment from Cryomech. This warranty covers all non-user
serviceable components of the air compressor. The warranty does not cover user-
serviceable parts.
If found to be defective and in accordance with the terms of the limited warranty,
Cryomech will provide warranty replacement parts at no cost to the customer. Customers
are responsible for all shipping and handling charges associated with warranty repair.
2.2 Conditions that can void the warranty
•Operation of the liquid nitrogen plant in any situation that does not meet the
specifications in this section will void the warranty. If you plan to operate the system
outside any of the specified conditions, contact Cryomech. See Section 5.
•Failure to follow these installation guidelines could result in voiding the warranty. See
Section 6.
•Cooling water must meet the requirements in Section 5. If water that does not meet
the cooling water specifications in Section 5 is introduced into the system, even for
cleaning purposes, it will void the warranty. See Section 6.
•A voltage deviation of more than 10% above or below the voltage rating can cause
compressor motor overheating and possible failure. Indications of operation outside
that voltage range will void the compressor warranty. See Sections 6 and 7.
•Do not allow the flex lines to come into contact with corrosives or any type of
commercial cleaning agent. Helium leaks caused by exposure to corrosives or
commercial cleaning agents will not be covered under warranty. See Section 6.
•Do not bend the flex lines to less than 10 inch (25 cm) radius or permanent damage
may occur. This type of damage is not covered under the warranty. See Section 6.
•The compressed air filters are not designed to remove vaporous water. Vaporous
water will pass through the filters and damage the N2generator. This type of damage
is not covered under the warranty. See Section 6.
•The maximum inlet air temperature to the N2generator /compressed air filter bank
panel is 125°F (52°C). Temperatures above 125°F (52°C) will damage the filter bank
components. This type of damage is not covered under the warranty. See Section 6.

Warranty
2-2
•The air compressor must be installed and operated according to the manufacturer’s
specifications included in the air compressor’s instruction manual. Failure to follow
the manufacturer’s instructions will void the warranty. See Sections 6 and 7.
•If the air compressor must be bolted to the floor, please pay special attention to the
mounting instructions included in Section 3 of the air compressor’s instruction
manual. Failure to mount the air compressor according to the manufacturer’s
instructions will void the warranty. See Sections 6 and 7.
•Do not allow the nitrogen flex line to come into contact with corrosives or any type of
commercial cleaning agent. Leaks caused by exposure to corrosives or commercial
cleaning agents will not be covered under warranty. See Section 6.
•Do not bend the nitrogen flex line to less than 5 inch (12 cm) radius or permanent
damage may occur. This type of damage is not covered under the warranty. See
Section 6.
•CP900 SERIES COMPRESSORS ONLY. Running the compressor package in
reverse for any significant length of time will void the warranty. If the power cord is
not wired properly the compressor will run in reverse and there will be no pressure
differential on the pressure gauges. Turn the system off immediately. Follow the
instructions in Step 5, below, to rewire the power cord correctly. See Section 7.
•If excessive amounts of condensate are allowed to accumulate in the filter bowls, the
condensate will move downstream and destroy the N2generator. This type of
damage is not covered under the warranty. See Section 7.
•Failure to maintain the system properly will void the warranty. See Section 8.
•When adding helium, the helium must be 99.999% pure. Contamination by other
gases will result in the freezing of the contaminant gases in the cold head because
their freezing temperature is much higher than that of helium. Contaminants in the
helium charge will severely degrade the cold head’s function and it will require factory
servicing. Contamination of the helium by other gases is a common cause of
premature failure and, unless resulting from a system failure, is not covered by the
warranty. See Section 8.
•Never wet either part of the system. Water getting into the system will void the
warranty. See Section 8.
14Feb07

3.2-N
Section 3
Safety

Safety
3-1
Section 3: Safety
3.1 Safety and information symbols
3.1.1 Equipment symbols
The safety and information symbol stickers placed on Cryomech Liquid Nitrogen Plants
as well as Cryorefrigerators are defined below.
Alternating current. The symbol signifies that alternating current is present.
Internal ground. This symbol represents an internal protective grounding
terminal. Such a terminal must be connected to earth ground prior to making
any other connections to the equipment.
Warning Icon. Refer to the documents that accompany the equipment.
The CE icon is placed on a product if the product has been tested for and
meets the safety standards set by the European Community. CE stands for
Conformité Européenne.
Power switch. This symbol designates an in/out or push/push switch.
Read the manual or handbook sign. When this symbol is found on a piece of
equipment, the user should read the whole manual before starting installation
or use. This symbol is found on the compressor package.
3.1.2 Icons in the manual
Definitions of Warning and Caution and Information icons in the manual
Warning Icon. A warning message is used when failure to observe
instructions or precautions could result in injury or death to humans.
Electrical Warning Icon. An electrical warning message is used when failure to
observe instructions or precautions could result in electrical shock or burns to
humans.
Caution Icon. A caution message is used when failure to observe instructions
or precautions could result in significant damage to equipment and/or
facilities.
Information Icon. The accompanying message contains information to aid the
operator in obtaining the best performance from the equipment or other
important information that does not involve danger to equipment or humans.

Safety
3-2
3.2 Warnings and cautions
Warnings and cautions for the Cryomech Liquid Nitrogen Plants are listed here by
subsystem. The same warnings and cautions appear in the appropriate places in the
unpacking, installation, operation and routine maintenance sections of this document.
3.2.1 Section 5. Specifications
Section 5.2 Technical specifications
CAUTION
Operation of the liquid nitrogen plant in any situation that does not meet the
specifications in this section will void the warranty. If you plan to operate the system
outside any of the specified conditions, contact Cryomech.
3.2.2 Section 6. Installation
Section 6.1 System installation
CAUTION
Failure to follow these installation guidelines could result in voiding the warranty.
WARNING
Do not allow the released oxygen, which enhances flammability, to accumulate in an
enclosed area.
CAUTION
To prevent damage to the nitrogen generator, do not block or restrict the flow from
the nitrogen generator’s vent. To prevent accidental flow blockage, do not install a
valve in the vent line.
WARNING
Personnel, including rescue workers, should not enter areas where the oxygen
concentration is below 19.5% unless provided with a self contained breathing
apparatus or air-line respirator.
Section 6.2 Dewar installation
WARNING
Personnel, including rescue workers, should not enter areas where the oxygen
concentration is below 19.5% unless provided with a self contained breathing
apparatus or air-line respirator.

Safety
3-3
Section 6.3 Helium compressor installation
CAUTION
Failure to follow these installation guidelines could result in voiding the warranty.
Section 6.3.1 Prepare the compressor package location
WARNING
The compressor package must be positioned to provide easy access to the front-
panel mounted circuit breaker.
Section 6.3.2 Connect the water lines to the helium compressor (water cooled
models only)
CAUTION
Cooling water must meet the requirements in Section 5. If water that does not meet
the cooling water specifications in Section 5 is introduced into the system, even for
cleaning purposes, it will void the warranty.
CAUTION
Do not apply heat to the cooling water inlet and outlet connectors located on the front
panel of the compressor.
Section 6.3.3 Connect the helium compressor package to the main power
CAUTION
A voltage deviation of more than 10% above or below the voltage rating can cause
compressor motor overheating and possible failure. Indications of operation outside
that voltage range will void the compressor warranty.
WARNING
Be sure to follow all local electrical codes and guidelines.
WARNING
One lead of the helium compressor package is grounded. Never bypass this ground
or attach the helium compressor package to an ungrounded circuit. A dangerous
electrical hazard will develop.

Safety
3-4
Section 6.3.4 Connect the helium flex lines to the cold head and the helium
compressor package
CAUTION
Follow the procedure carefully when connecting and disconnecting the helium flex
lines. Failure to follow the procedure can cause accidental coupling disassembly,
destruction of the sealing O-ring, and helium loss.
CAUTION
Do not allow the flex lines to come into contact with corrosives or any type of
commercial cleaning agent. Helium leaks caused by exposure to corrosives or
commercial cleaning agents will not be covered under warranty.
CAUTION
Do not bend the flex lines to less than 10 inch (25 cm) radius or permanent damage
may occur. This type of damage is not covered under the warranty.
WARNING
Never remove the Aeroquip®couplings from the helium flex lines without first
relieving the helium charge in the line to acceptable levels. The pressure in the hose
can blow off the coupling with sufficient force to cause injury.
Section 6.4 N2generator/filter bank panel installation
CAUTION
If the N2generator /compressed air filter bank panel is exposed to freezing ambient
temperatures, 32°F (0°C) or lower, the water collected in the filter bank will freeze,
destroying the filters, drain lines and automatic drain valve (ADV).
CAUTION
The compressed air filters are not designed to remove vaporous water. Vaporous
water will pass through the filters and damage the N2generator. This type of damage
is not covered under the warranty.
CAUTION
The maximum inlet air temperature to the N2generator /compressed air filter bank
panel is 125°F (52°C). Temperatures above 125°F (52°C) will damage the filter bank
components. This type of damage is not covered under the warranty.

Safety
3-5
CAUTION
Do not apply heat to the automatic drain valve. Doing so will damage or destroy the
drain valve.
Section 6.5 Refrigerated air dryer installation (option)
CAUTION
The refrigerated air dryer must be installed and operated according to the
manufacturer’s specifications included in the dryer’s instruction manual. Failure to
follow the manufacturer’s instructions will void the warranty.
Section 6.5.2 Connect the dryer to the main power
CAUTION
A voltage deviation of more than 10% above or below the voltage rating can cause
compressor motor overheating and possible failure. Indications of operation outside
that voltage range will void the dryer warranty.
Section 6.6 Air compressor installation
CAUTION
The air compressor must be installed and operated according to the manufacturer’s
specifications included in the air compressor’s instruction manual. Failure to follow
the manufacturer’s instructions will void the warranty.
Section 6.6.2 Mount the air compressor
CAUTION
If the air compressor must be bolted to the floor, please pay special attention to the
mounting instructions included in Section 3 of the air compressor’s instruction
manual. Failure to mount the air compressor according to the manufacturer’s
instructions will void the warranty.
Section 6.6.4 Connect the air compressor to the main power
CAUTION
A voltage deviation of more than 10% above or below the voltage rating can cause
motor overheating and possible failure. Indications of operation outside that voltage
range will void the compressor warranty.
WARNING
Be sure to follow all local electrical codes and guidelines.

Safety
3-6
WARNING
One lead of the air compressor is grounded. Never bypass this ground or attach the
air compressor to an ungrounded circuit. A dangerous electrical hazard will develop.
Section 6.6.5 Check for correct rotation
CAUTION
Do not start the compressor before checking for proper oil level. Refer to the air
compressor instruction manual for proper oil charge.
Section 6.8 Air compressor to N2generator/filter bank panel connection
CAUTION
The compressed air filters are not designed to remove vaporous water. Vaporous
water will pass through the filters and damage the N2generator. This type of damage
is not covered under the warranty.
CAUTION
The maximum inlet air temperature to the N2generator /compressed air filter bank
panel is 125°F (52°C). Temperatures above 125°F (52°C) will damage the filter bank
components. This type of damage is not covered under the warranty.
CAUTION
The filter bank's ability to remove water from the incoming compressed air is
dependent on the temperature of the incoming air. As a rule, the incoming
compressed air temperature should be within 10°F (6°C) of the ambient temperature
for optimal operation of the compressed air filter bank. The maximum inlet air
temperature is 125°F (52°C).
Section 6.9 N2generator/filter bank panel to dewar connection
CAUTION
Do not allow the nitrogen flex line to come into contact with corrosives or any type of
commercial cleaning agent. Leaks caused by exposure to corrosives or commercial
cleaning agents will not be covered under warranty.
CAUTION
Do not bend the nitrogen flex line to less than 5 inch (12 cm) radius or permanent
damage may occur. This type of damage is not covered under the warranty

Safety
3-7
3.2.3 Section 7. Operation
Section 7.1 Starting the refrigerated air dryer (option)
CAUTION
The refrigerated air dryer must be installed and operated according to the
manufacturer’s specifications included in the dryer’s instruction manual. Failure to
follow the manufacturer’s instructions will void the warranty.
Section 7.2 Starting the air compressor
CAUTION
The air compressor must be installed and operated according to the manufacturer’s
specifications included in the air compressor’s instruction manual. Failure to follow
the manufacturer’s instructions will void the warranty.
CAUTION
If the air compressor must be bolted to the floor, please pay special attention to the
mounting instructions included in Section 3 of the air compressor’s instruction
manual. Failure to mount the air compressor according to the manufacturer’s
instructions will void the warranty.
Section 7.3 Purge the dewar
CAUTION
Make certain the needle valve is closed before opening the compressed air outlet
valve. The dehumidifier may rupture if it is exposed to rapid pressurization.
Dehumidifier failures resulting from rapid pressurization are not covered under the
warranty.
Section 7.4.1 Checks before operating
CAUTION
A voltage deviation of more than 10% above or below the voltage rating can cause
compressor motor overheating and possible failure. Indications of voltage operation
outside that range will void the compressor warranty.