AEC Continuous Vacuum/Pressure Conveying Systems - Manual (Page 49)

Page 48 Single- and Dual-Blower Continuous Vacuum/Pressure Systems
5-6 Shutting Down the System
In certain operating conditions, pressing Emergency Stop or Purge Stop shuts
down the system. Refer to the following sections for an explanation of the operation
and conditions of each.
Operating Conditions Shutdown
The vacuum/pressure pump(s) automatically shut(s) down in the following conditions.
High Level Signal
The level switch in the silo or throwout cone signals a full condition. A purge
stop sequence occurs and the system shuts down.
Push the Start button to re-start the system.
High Vacuum
The vacuum switch senses vacuum in excess of 12 in. Hg (406.8 millibars) on
the vacuum side of the system. The Purge Stop sequence activates and the
entire system shuts down. Find the blockage and remove it.
Push the Start button to re-start the system.
High Pressure
The pressure switch senses pressure in excess of 6 psig (41.4 kPa/0.41 bars) on
the pressure side of the system. The vacuum/pressure system shuts down. Find
the blockage and remove it.
Push the Start button to re-start the system.
Note: A high vacuum condition causes units to begin the purge cycle, interrupting
vacuum conveying. In SVP systems when the purge cycle occurs, the pump
goes into vent cycle. In CVP/CPP systems, the vacuum unit turns off for a
preset time period. A high pressure condition causes the mechanical relief
valve to open on the pressure unit, affecting pressure conveying if the high
pressure switch fails to shut down the units.
Emergency Shutdown
In an emergency, press Emergency Stop (1PB) to stop system operation. Expect to
encounter material plugging the pressure line on subsequent startups.
Normal Shutdown
Press Purge Stop (3PB) for normal operational shutdown. Vacuum conveying stops
immediately. After the system purges the cyclone/filter receiver, blow-through adapter,