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