CAIRE HELiOS Plus Technical & Service Manual page 12

V
Theory of Operation
Continuous Flow
When the FCV is on continuous (C) mode, the oxygen flow
is delivered in a continuous stream rather than a bolus and tail
flow deivery. In these settings, the flow orifice plate blocks the
gas supply to the area under the slave diaphragm. The negative
pressure from the patient's first breath vents any residual pres-
sure that may be present under the slave diaphragm and pushes
it off of the demand flow port. This causes a continuous flow of
oxygen.
It is important that the FCV still sense a breath periodically in
continuous flow to keep the slave diaphragm pushed down. If a
length of time passes without any negative pressure applied by a
patient's breath, the diaphragm may close and continuous flow
may stop.
Liquid Level Measurement
H300 & H850 units are equipped with mechanical spring scales
for liquid measurement. The spring indicator is built into the
rear cover. When the unit is suspended by its contents indica-
tor strap and held perpendicular to the ground, a green bar is
displayed in a window on the back of the unit. The height of the
green bar is proportional to the weight of liquid oxygen inside
the H300 or H850.
Indicator
Springs
Figure 11: Contents Indicator
Serial Number Identification
1 Units manufactured prior to October 2010 are identified by
unique 8-digit serial numbers shown in Figure 12. The serial
number contains the year and calendar day of manufacture,
as well as the unit's production number that day. The H300
& H850 serial number is etched on the cryogenic container
and is visible through the contents indicator window on the
back of the unit.
Figure 12: Serial Number Structure (Before 2010)
2 As of October 2010, H300 & H850 units are identified by
differently structured serial numbers as shown in Figure
13. The number begins with the letters CB signifying the
manufacturing location, followed by the reservoir product
code B30, followed by digits signifying the year of manu-
facture, followed by a two digit number to signify the week
of the year that the unit was manufactured and ends with
digits signifying the unit's production number for that week.
This serial number is found on a white, rectangular sticker
placed on the outside of the cryogenic container. It can be
seen thorough the vents on the side of the outer case. Units
manufactured after August 2016 will have the UDI label.
The serial number structure remains the same.
Figure 13: Current Serial Number Structure
HELiOS Portables Technical Service Manual • PN 20562190 Rev E
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