Theory Of Operation - CAIRE Hi Flow Stroller Technical & Service Manual

VI

Theory of Operation

Filling
1. Method
The Hi Flow Stroller is a portable unit designed to be filled by the
patient from a Liberator, Low Loss Reservoir, or other compatible
unit.
The unit is filled by coupling the quick disconnect valve of the
Hi Flow Stroller with the quick disconnect valve on the Reservoir
and opening the vent valve on the portable. Liquid oxygen is
forced up the Reservoir fill tube, through the coupled quick con-
nectors, and into the inner vessel of the Hi Flow Stroller.
There will be some oxygen vaporized during filling. This gas is
discharged through the vent valve. When the unit is full, liquid
oxygen is expelled through the vent valve. Closing the vent valve
and separating the units terminates the fill process.
2. Saturation Pressure
The liquid oxygen saturation pressure can seriously affect the
overall efficiency and operation of the Hi Flow Stroller.
a. If the saturation pressure of the liquid in the fill source is
greater than 30 psig (2,1 bar), high filling losses and/or fro-
zen open relief devices may result.
b. If the saturation pressure of the liquid in the fill source is be-
low 18 psig (1,2 bar), below tolerance flow rates may result.
FIGURE 2: Filling
Gas
Vent Valve
PRV FCV
SRV
Liquid
Fill Connection
(QDV)
Oxygen Withdrawl
With oxygen in the unit, and the vent valve closed, the pressure
in the inner vessel will remain at or near the primary relief valve
pressure of 19.7 - 20.6 (1,35 - 1,42).
At operating pressure and with the flow control valve at any set-
ting other than Off, pressure forces liquid oxygen up the liquid
withdrawl tube and into the breathing coil. In the breathing coil,
liquid oxygen absorbs heat and vaporizes, warming to almost am-
bient temperature by the time gas is dispensed by the flow control
valve to the patient.
FIGURE 3: Oxygen Withdrawl
Gas
Hi Flow Stroller Technical Service Manual • PN 14314465 Rev F
PRV FCV
Gas to Patient
SRV
10