Level sensor
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Dear Tim, Hi.
If the device you require is a kind of level sensor (e.g. mounted inside a
vertical silo) a possible solution is to lower a weight attached to a line
(like a fishing line with a sinker) through a spring-loaded pulley until the
force on the pulley drops. At that moment the weight will have reached and
is resting on the free surface of the material.
I know of several implementations of this principle to measure the level of
powdery or granular materials. Typically it is implemented as a stepper
motor directly driving the reel where the line is wound. A simple
microswitch senses the tension of the drop line. A low-range PLC or
microcontroller is used to command the lowering and rewinding of the weight,
to count stepper pulses and monitor the microswitch. Measures are taken on
demand of course (not continuously) and can be repeated every 5-20 seconds
or more, depending on silo height.
The main elements (motor, reel, electronics) can be placed safely outside of
the silo with only the line with the weight dropping inside through a
gasketed hole (not air-tight).
Hope this helps.
Regards,
George Chamilothoris.
If the device you require is a kind of level sensor (e.g. mounted inside a
vertical silo) a possible solution is to lower a weight attached to a line
(like a fishing line with a sinker) through a spring-loaded pulley until the
force on the pulley drops. At that moment the weight will have reached and
is resting on the free surface of the material.
I know of several implementations of this principle to measure the level of
powdery or granular materials. Typically it is implemented as a stepper
motor directly driving the reel where the line is wound. A simple
microswitch senses the tension of the drop line. A low-range PLC or
microcontroller is used to command the lowering and rewinding of the weight,
to count stepper pulses and monitor the microswitch. Measures are taken on
demand of course (not continuously) and can be repeated every 5-20 seconds
or more, depending on silo height.
The main elements (motor, reel, electronics) can be placed safely outside of
the silo with only the line with the weight dropping inside through a
gasketed hole (not air-tight).
Hope this helps.
Regards,
George Chamilothoris.