Chapter 2 – Installation
Page 2-4
TestEquity 3007C Temperature Chamber
LN2 (Liquid Nitrogen) Installation (Option 0018)
Liquid Nitrogen Safety Notices
!
WARNING:
Liquid n
itrogen is extremely cold (−190°C or −320°
F). It can cause severe
burns, frostbite, or eye damage. When handling liquid nitrogen containers or
piping; wear goggles for eye protection, protective clothing, and thick
impervious gloves (such as welder’s leather).
!
WARNING:
The connecting tube must include a relief valve designed for use with liquid
nitrogen if a manual or automatic isolation valve is present at your source of
supply or at any point between the source and the connection point on the
back of the 3007C Chamber. This relief valve must be rated for at least 35
psig and less than 100 psig. It is needed to prevent excessive pressure from
developing when the nitrogen in the connecting line evaporates during off
cycles. Care should be exercised in sighting the relief valve to assure that
should it relieve, the effluent will not discharge towards operating personnel.
!
WARNING:
All liquid nitrogen connecting piping or tubing must be well insulated with
appropriate vapor sealed or vacuum jacketed materials. Un-insulated nitrogen
connecting lines can condense pure oxygen on their surface since liquid
nitrogen is colder than liquid oxygen. Liquid oxygen can present a
spontaneous fire hazard when spilled onto organic materials.
!
WARNING:
Nitrogen gas is heavier than air. It makes up about 78% of the Earth’s
standard atmosphere, is non-toxic, colorless, odorless, and tasteless. Pure
nitrogen gas in a closed area can present an asphyxiation hazard (suffocation)
without warning.
Liquid Nitrogen Installation
Your chamber may be configured with LN2 Boost Cooling capability. The LN2 system is
designed to operate with a low pressure Dewar or low pressure bulk supply system. A customer-
provided source of liquid nitrogen at a supply pressure between 10 psig and 75 psig is required
for LN2 Boost Cooling.
A high pressure Dewar may be used but the supply must be carefully regulated to less than
75 psig to prevent venting by the chamber’s LN2 pressure relief valve which is set for 100 psig.
If a high pressure Dewar is used, provide a liquid nitrogen rated relief valve with a setting of not
more than 100 psig in the connecting line to relieve pressure in the event that the supply hand
valve on the container is manually closed.
The supply connection is on the upper back of the chamber centered between the two fan motors.
This connection is a 3/8-inch JIC (Joint Industrial Council) stainless steel 37-degree flare fitting
rated for very low temperature operation. The fitting is mounted on a non-metallic thermal
breaker to help limit frost formation and condensation.
