Process Automation
Technical Data

Process Automation
Technical Data

LEVEL CONTROL ON FEEDERS, ORE PASSES AND SILOS

INDUSTRY
:
Mining / Materials Handling / Cement / Ore Processing
PROCESS
:
Feeding process material to and from storage.
PROBLEM
:
Rocks falling on feeders or bottom of silos, may cause damage due to the direct impact.
SOLUTION
TO THE
PROBLEM
:
It is general practice to leave a cushion of process material at the bottom of silos, on feeders out of silos
and in ore passes.
EQUIPMENT
USED
:
The Process Automation series NPL 300 point level gauges are extensively used as Low-Low level
detectors to detect extreme low levels which may not be exceeded. These level detectors may be used to
automatically stop the outfeed of process material to ensure that sufficient material remains behind in the
silo to cushion the fall of new incoming material. Pan feeders, apron feeders, vibratory feeders and other
feed/storage equipments can be protected by the use of the Process Automation NPL 300 low level
gauge.
SELF-CHECK
FACILITY
:
In an application where the chute/pipe feeder/ore pass etc. must never be allowed to go empty, the Low
Low Level Gauge is intended to almost never have to operate i.e. the source will always be shielded off
from the detector by process material except under dangerously faulty process conditions.

How will one know whether the detector is still in good operating condition and will give the alarm
when the situation so requires?

Our complete system check monitors 100% of the detector unit, from the gamma detector tube to the
output relay. While the detector is shielded from the source by the process material, it still picks up
background radiation from the environment. This low level radiation holds in the system check relay and
indicates that the gauge will function normally when exposed to the source on the other side of the vessel,
should a low low level condition occur.