VAC ______________________
Vacuum/Atmospheres
4-1
GENERAL
SECTION 4. OPERATIONS & THEORY
The HE-493 ORI-TRAIN is designed to control the oxygen and moisture
content in the atmosphere of a sealed glove box. It can run continu
ously and need not be turned off, except for maintenance.
The heart of the HE-493 is a chemical purifier. The purifier canister
contains a moisture adsorbent and an oxygen reactant.
The adsorb
ent removes water vapor from any gas which passes through it. The
oxygen reactant
combines chemically with oxygen, thereby removing
oxygen from the gas which is circulated through it. When the agent
becomes saturated with oxygen it sho4ld be regenerated.
This section will explain further the purifier and its operation (para
graph 4-2), and the process of regenerating the purifier ( paragraph
4-8). Oxygen and water removal, the blower, and the vacuum pump will
also be discussed in this section.
4-2 PURIFIER
The purpose of the purifier is to remove moisture and oxygen from the
gas flowing through the controlled atmosphere of a glove box. The
purifier contains two chemical purification agents. One is a molecular
sieve which removes moisture from gas flowing through it by a process of
molecular absorption. There are two layers of molecular sieve in the
purifier canister, four pounds above the lower plenum, and 1-3/4 pounds
below the upper plenum. The other agent is an oxygenreactant, Q-5, five
pounds of which constitutes the middle layer in the purifier canister.
The HE-493 purifier is constructed so that in normal operation the gas
to the purifier enters the port which opens into the upper plenum of the
canister. (See Figure 4-1.) Gas flows from this upper plenum down
4-1
HE-493-IU-7 /90