Eppendorf LN2 Backup System - Manual (Page 13)

Introduction
New Brunswick LN2 Back-up System
English (EN)
13
5 Introduction
5.1 Scope of manual
This manual provides the user with the necessary information for the installation and operation of the LN
2
Back-up System for New Brunswick Innova ® and Premium ranges of Ultra Low Temperature Freezers.
5.2 LN
2
Back-up System
The LN
2
Back-up System system is designed to provide a means of maintaining the contents of a New
Brunswick Ultra Low Temperature Freezer at a preset temperature should the power or the refrigeration
system fail.
The freezer is fitted with a platinum resistance thermometer (referred to as a temperature sensor or probe)
to measure the internal temperature, a solenoid valve and a door switch.
A freestanding control unit and cables are provided. Transfer lines and connectors are supplied to connect
between the solenoid valve and the LN
2
low-pressure storage Dewar. Dewars are not provided.
The backup control unit is plugged into the power supply and a temperature selected between -50 °C and
-85 °C. When the temperature within the freezer rises above the selected backup temperature, the solenoid
valve switches on and LN
2
is continuously injected into the body of the freezer.
The solenoid valve continues to inject LN
2
until the temperature within the freezer drops below the preset
value selected on the Temp Set dial. If a power failure occurs, a battery within the back-up unit will
continue to operate the back-up system for up to 48 hours.
When the door or lid of the freezer is opened, the door switch is activated to prevent additional gas
injections while the freezer is open. This prevents the freezer user from being burned by the extremely cold
gas stream.
5.3 Product versions
A low-pressure liquid nitrogen storage Dewar with a pressure-regulated liquid withdrawal
port is required. Liquid nitrogen must be used to ensure proper operation.
Back-up Systems
Freezer type Part number
Innova 115 V / 220 V 60 Hz CGA Bottle Fitting U9044-0002
Innova 230 V 50 Hz BS341 Bottle Fitting U9044-0004
Premium 115 V / 220 V 60 Hz CGA Bottle Fitting U9044-0006
Premium 230 V 50 Hz BS341 Bottle Fitting U9044-0008