thread698-149752
The best device I have come across is a direct mass per unit volume device. This measures a continuous and good representation of the media ( a 12" ID is 7 feet long, a 40" ID is 12 feet long). The signal is interrogated at 110 Hz, giving a response time is 45 milleseconds, so nothing is missed. The flow tube is reinforced rubber with typically 1/2" thick natural gum rubber, giving many years service life. Even then, the flow tube is easily replaceable.
I say this technique is the best in light of problems I've had with the following:
The trouble with nuclear devices are the surveys, safety officer, possible health hazards and those darned wipe tests.
I have found ultrasonic density measurement hit and miss; above 10% dry solids it has to be damped so much that errors are significant. Damping does not provide the true average.
Microwave techniques should not be used because the dielectric characteristic of mining and dredging slurries is too variable....a good manufacturer will admit to that.
The best device I have come across is a direct mass per unit volume device. This measures a continuous and good representation of the media ( a 12" ID is 7 feet long, a 40" ID is 12 feet long). The signal is interrogated at 110 Hz, giving a response time is 45 milleseconds, so nothing is missed. The flow tube is reinforced rubber with typically 1/2" thick natural gum rubber, giving many years service life. Even then, the flow tube is easily replaceable.
I say this technique is the best in light of problems I've had with the following:
The trouble with nuclear devices are the surveys, safety officer, possible health hazards and those darned wipe tests.
I have found ultrasonic density measurement hit and miss; above 10% dry solids it has to be damped so much that errors are significant. Damping does not provide the true average.
Microwave techniques should not be used because the dielectric characteristic of mining and dredging slurries is too variable....a good manufacturer will admit to that.