AEC OS Series Gravimetric Batch Blenders - Manual (Page 33)

Page 32 of 118
2-9 Electric Safety Interlock Switch (All Models)
A unique electric safety switch is used to shut off power to the blender any time the
mixer door is opened. Do not tamper or alter with this switch in any way.
Electrical safety interlock switch
(Located on mixer door)
2-10 Air Pressure Safety Circuit (If Equipped-not included on
“CE” models)
The OS/OA blending system may be equipped with an air pressure safety
system that will drop the air pressure from a pilot operated master air valve and
an air cylinder actuated electrical safety switch.
Each unsafe access opening of the blender is provided with an air safety switch
that is held in the closed position by an access door, metering device, or any
other unsafe opening that could be accessible to the operator without the use of
a tool.
If any one of the openings to the blender is opened that would allow access to
the interior of the blender, an air safety switch will open. This air safety switch
opens to atmosphere, the hold in air pressure circuit for the master air valve,
and the air actuated electrical master safety switch.
This will cause the air supply to the blender to be cut off to the solenoid valves,
and the electrical supply to the computer control panel will be disconnected.
The only way a component to the blender could be operated is for the opened
safety switch to be physically held closed, and for the computer to be restarted
by a key stroke or for the safety switch to be held in while depressing the
manual actuator button on a solenoid valve with a screwdriver, etc.
The safety system must have (2) things happen at the same time to be
bypassed. The only way this can happen is to have an operator or maintenance
person physically perform these acts.
Interlock Switch