SECHRIST 3500 - Page 5

INTRODUCTION
The SECHRIST Air-Oxygen Mixer has been designed for
durability and serviceability. If the criteria for the gas supply
are met and the supply is satisfactorily clean and dry, the
SECHRIST Mixer should provide years of use with relatively
little care and service. However, should it become necessary,
these instructions are provided to serve as a guide for qualified
technicians to service and repair the SECHRIST Mixer.
This manual is designed to take the technician through a step-
by-step process to:
— Test for proper operations -
— Troubleshoot any malfunctions
— Calibrate the Mixer if necessary
— Disassemble and reassemble the Mixer
— Keep the Mixer operating at its optimum efficiency
of design.
This manual provides information in a general to specific
manner. Section I describes all tools and test equipment
required to calibrate and service SECHRIST Air-Oxygen
Mixer products. Section II details the testing procedures
necessary to determine optimum working conditions of the
SECHRIST Mixer. If service is necessary, based on the
outcome of the testing, a Troubleshooting Guide is given in
Section II to determine which component module of the Mixer
is involved and what procedures are recommended.
The procedures necessary for service are given next in the
Calibration Section (II) and the Disassembly and Reassembly
Section (IV). These sections are broken down into the three
component modules of the Mixer. These three modules serve
unique purposes. The Proportioning Module does the actual
gas mixing and proportions the outflow. The Pressure
Balancing Module takes the incoming gas pressures, with a
potential differential of 20 p.s.i., and reduces the differential to
3 cm. of water pressure, thereby nullifying the differences and
equalizing the incoming pressures. The Alarm Module sounds
a continuous reed alarm if the incoming gas pressures differ
more than 25 p.s.i. When the alarm is activated, the gas with
the highest pressure will be delivered by the Mixer until supply
gas pressures are reestablished.
Photographs and diagrams are given to provide a visual display
of the instructions. Exploded diagrams of individual modules
will provide a structured way of following the step-by-step
instructions for disassembly and reassembly.
NOTE: The greatest enemy of all gas mixing devices is
contamination from the supply gases, especially the
Medical Breathing Air supply. Required service can
be significantly reduced by assuring the quality of the
supply gases and performing routine filter
maintenance.
WARNING
This precision gas mixing device is intended for use
with Medical Breathing Air and Medical Breathing
Oxygen only. Do not modify inlets to accommodate
other breathing gases, especially anesthetic gases.
Maintenance
/
Repair
Qualifications
The
Maintenance,
Repair,
and
Testing
procedures
covered
in
this
manual
are
to
be
performed
by
individuals qualified
in the servicing and
maintenance
of
medical
life
support
equipment.
ONLY
procedures
covered
in
this
manual
are
to
be
performed
in
the
field.
Procedures
requiring
more
extensive
electronic/pneumatic
trouble-shooting,
and/or
electronic
component
replacement
must
be
performed
by
Sechrist
Industries,
Inc.