CAIRE HELiOS Plus, Техническое и сервисное руководство

Страница: 9 / 59

HELiOS Portables Technical Service Manual • PN 20562190 Rev E
8
HELiOS P
or
tables
Theory of Operation
V
Cryogenic Container
The H300 & H850 cryogenic container is designed to slow the
transfer of heat from the atmosphere to the liquid oxygen con-
tents.
The contents of H300 & H850 portables are contained within a
double-walled, vacuum-insulated cryogenic container. The liquid
oxygen is stored in an inner container that is suspended within an
outer container. Air is removed from the space between the two
containers to minimize heat transfer between the warm outer tank
and the cold inner tank. This is achieved by applying a vacuum
though the outer container’s vacuum port.
In addition to the vacuum insulation, a molecular sieve is placed
within the vacuum space against the inner container to absorb
any moisture or gas molecules that remain in the vacuum space.
Also, the inner containers of the H300 & H850 are wrapped in
multiple layers of an aluminum foil and fiberglass paper insula-
tion to reflect radiant energy and minimize heat transfer.
The unique design of cryogenic container and the location of the
gas withdrawal tube allow the unit to be operated safely on its
back. If the H300 or H850 is laid flat on its back, liquid oxygen
will not escape and be discharged. The unit can be operated up-
right, flat on its back, or any position in between.
Filling
The H300 & H850 potable units are designed to be filled from
any top-fill (TF) reservoir with a standard Puritan Bennett male
fill connector (QDV). Below is a list of CAIRE reservoirs that
will fill the H300 & H850.
• Companion C21, C31, C41
• Liberator (TF/DF) 10, 20, 30, 37, 45, 60
• Low Loss (TF/DF) 31, 42
• HELiOS Universal U36, U46
• HELiOS Standard H36, H46
The H300 & H850 is filled by coupling its female quick discon-
nect valve (QDV) with the male QDV on the reservoir and open-
ing the vent valve.
Once the QDV’s have been connected, the vent valve on the port-
able unit must be opened to initiate flow of liquid into the unit.
When the vent valve is opened, it vents the contents of the inner
container to the atmosphere.
Venting the gas inside of the container creates a pressure drop
inside of the H300 or H850. This pressure differential causes liq-
uid oxygen to flow up the reservoir fill tube, through the coupled
QDV’s, and into the inner container of the H300 or H850.
At the beginning of a fill, the liquid oxygen that leaves the res-
ervoir will vaporize into a gas because the inside of the H300
or H850 container is relatively warm. This gas is discharged
through the vent valve. After a short time, the container cools
and liquid oxygen is contained.
When the unit is full, liquid oxygen is expelled through the vent
valve. The venting sound also changes and the liquid oxygen
creates a dense vapor cloud coming from under the reservoir’s
shroud. Closing the vent valve and separating the H300 or H850
from the reservoir terminates the fill process.
Figure 5 is a diagram showing the filling process of a portable
unit.
The saturation pressure (explained in Section VII of this manual)
of the liquid oxygen can seriously affect the overall efficiency
and operation of the H300 & H850.
Figure 4: Cryogenic Container Design
Figure 5: Filling Process
Please note that the section outlined in the above filling process shows a
configuration of a unit equipped with an optional CPC Connector Kit.