AEC Continuous Vacuum/Pressure Conveying Systems - Manual (Page 20)

Single- and Dual-Blower Continuous Vacuum/Pressure Systems Page 19
Every effort has been made to incorporate these standards into the design of the
Vacuum/Pressure Conveying System; however, it is the responsibility of the
personnel operating and maintaining the equipment to familiarize themselves
with the safety procedures and the proper use of any safety devices.
2-8-3 Fail Safe Operation
If a safety device or circuit should fail, the design must be such that the failure
causes a “Safe” condition. As an example, a safety switch must be a normally
open switch. The switch must be held closed with the device it is to protect. If
the switch fails, it will go to the open condition, tripping out the safety circuit.
At no time should the safety device fail and allow the operation to
continue. For example, if a safety switch is guarding a motor, and the safety
switch fails, the motor should not be able to run.
2-8-4 Safety Device Lock-Outs
Some safety devices disconnect electrical energy from a circuit. The safety
devices that are utilized on this equipment are primarily concerned with the
pneumatics and electrical power disconnection, and the disabling of moving
parts that may need to be accessed during the normal operation of the machine.
Some of the safety devices utilize a manual activator. This is the method of
initiating the safety lock out. This may be in the form of a plug, disconnect
plug, lever or a handle. Within this lockable handle, there may be a location for
a padlock. Personnel servicing the equipment should place a padlock in the
lockout handle.
WARNING!
Always disconnect and lockout all electrical power and pneumatic
(i.e. compressed air) sources prior to servicing or cleaning any
Vacuum/Pressure Conveying System. Failure to do so may result
in serious injury.
At no time must anyone remove the lockout or reconnect the twist
plug, other than the person who installed the lockout or who
unplugged the twist plug.
2-8-5 Lock-Outs, Plugs, and Other Safety Devices
The Vacuum/Pressure Conveying System utilizes several types of
safety devices.
The Line Cord Plug
This line cord plug allows the operator or maintenance personnel
to unplug the conveying system from its power source and tag it
out. This plug may be tagged with any number of approved