SECHRIST 3500 - Page 9

2.0
3.0
4.0
5.0
1.5 The sampling rate should be:
7LPM for Low Flow
15 LPM for Hi/Low Flow.
Proportioning Module.
2.1 Set O; pressure and air pressure to 50 p.s.i.
2.2 Compare O> analyzer readings to Mixer settings
of .21, .40, .60, .80 and 1.0.
2.3 The Mixer has a specified accuracy of 13% If
the FIO> varies more than +4% between the
Mixer and O» analyzer reading, calibration or
service may be necessary (see Troubleshooting
Guide).
2.4 There is a constant bleed of mixed gas from the
bottom of the Proportioning Module. This bleed
is approximately 3 1/2 LPM for Low Flow and
8 1/2 LPM for Hi/Lo Flow. This is needed to
maintain accurate FIO s at very low flows.
These bleed rates are predetermined by the
factory and can not be reset in the field.
Pressure Balancing Module.
3.1 With same test system set up as above, select an
FIO of .60 and observe the O2 analyzer
reading.
3.2 Vary the inlet pressures to the Mixer to 40 p.s.i.
O; and 60 p.s.i. air and then to 60 p.s.i. Oz and
40 p.s.i. air. If FIO2 varies more than +1%
from initial O analyzer reading, calibration or
service may be necessary (see Troubleshooting
Guide).
Alarm Module.
4.1 Set air and O2 supplies to 50 p.s.i.; alarm should
be silent. '
4.2 Slowly reduce air inlet supply; the alarm should
sound between 24 and 28 p.s.i. and O analyzer
should read 100%. Increase air inlet supply,
slowly, to 50 p.s.i.; alarm should reset at or
before 40 p.s.i.
4.3 Repeat step 4.2 varying the O2 inlet supply;
when alarm sounds, O; analyzer reading should
be 21%.
4.4 If alarm does not function as per above
specifications, calibration or service may be
necessary (see Troubleshooting Guide).
Air Inlet Filtration System (most frequent service
required).
5.1 Totestthe pressure drop through the water/trap
filter or the internal air inlet filter, a test port has
been provided on the rear of the Mixer above
the air inlet.
5.2 With 1/4" nut driver, remove plug from test
port and install a Brass 10-32 x 1/16 fitting
(P/N IV-310) (see Tool Kit)
5.3 Connect a high pressure gauge (0 to 60 p.s.i.) to
10-32 fitting.
54 With flow set at 7 LPM for Low Flow(15 LPM
for Hi/Lo Flow), set mixer knob to .21. Observe
pressure indicated at test port.
5.5
FIO; RANGE:
ACCURACYY:
If the difference between the pressure at the test
port and the inlet pressure is greater than 10
p.s.i., replace either or both air inlet filters (see
Routine Maintenance section).
SPECIFICATIONS
.21 +.01 to 1.0 — .01
13%
MAXIMUM FLOW:
Model 3500 (Low Flow):
40 LPM @ «60 FIO,
setting with 50 p.s.i. (@
1.5 SCFM minimum flow)
inlet pressures
Model 3500HL (Hi/Lo Flow): 100 LPM @ .60 FIO,»
NOMINAL SUPPLY
setting with 50 p.s.i. (@
1.5 SCFM minimum flow)
inlet pressures
50 p.s.i. £10 p.s.i. (@ 1.5
PRESSURES** SCFM minimum flow).
BLEED FLOW:
Model 3500 (Low Flow): 3.0 to 4.0 LPM @ 7 LPM
Flow
Model 3500HL (Hi/Lo Flow): 7.5 to 9.5 LPM @ 15
LPM Flow
DIMENSIONS:
Model 3500 (Low Flow): HEIGHT: 6°
WIDTH: 6°
DEPTH: 6°
Model 3500HL (Hi/Lo Flow): HEIGHT: 6°
WEIGHT:
WIDTH: 6” (Pole
Mount)
6 1/2” (Wall
Mount)
6" (Pole
Mount)
5 1/2" (Wall
Mount)
DEPTH:
6 lbs.
*NOTE: The Mixer will maintain the delivered FIO) within
+1% of the selected value with fluctuations of the
supply pressures. The additional 2% error is
caused by the readability of the set point and scale
error.
**NOTE: The outlet pressure of the Mixer will always be
slightly lower than the lower of the two inlet
pressures. Some respiratory care equipment
attached to the Mixer may require closer tolerances:
consult the manufacturer's instructions.