Ultrasonic - On Stone Bin

[peng]

I am working on an application with an Aggregate company.



The company has several stone bins on site that fill with material as the plant runs. They then in turn drive a truck under the bin and open a chute to remove the material (crushed stones) into the truck. I would like to set up a system with an ultrasonic detector (????) that would indicate when the bins reach a certain level. The indicator being a light on the side of the bin and a warning on the main computer in the control room tied in through the PLC.

Does any one have any suggestions as to what kind of sensors do I need to be looking at? Brands, suppliers, etc.



Also would like to show the level on the HMI as well.

Would appreciate your suggestions.

 

[OkiePC]

You might also consider using scales. We use these with amazing reliability in our meat grinding operations:

http://www.emerywinslow.com/

Paul

 

[OZEE]

How much dust is there? I think we've finally found something that will work in flour, but it's a little pricey...

 

[Nick B]

I'm not sure this is a good choice for Ultrasonic. Maybe a Radar type would be better.


Nick

 

[peng]

It is dusty and muddy.

 

[peng]

I am thinking about it too, after reading some previous posts here on this site. I have e-mailed some of the suppliers about the application. I have not heard anything yet.

Why would you recommend Radar as suppose to Ultrasonic.

Has any one done this sort of application with a cement or aggrigate plant.

 

[OZEE]

Radar will be a much better answer in cement/aggregate -- especially if there's dust. The dust will mess up the ultrasonic readings...

You might want to search for "Guided Radar" -- Magnetrol and Ohmart-Vega are two that come to mind.

 

[Sliver]

We are a cement plant.

We use ultrasonics (Milltronics/Siemens) for most bins (crushed stone and powder) 50' and less.
We use radar (Vega) Vegapuls 68 on our 200' silos (powder) because of dust penetration.

Brian

 

[peng]

Brian, do you have the model numbers for the ultrasonics (Milltronics/Siemens). I e-mailed the my Siemens distributor for some help when I talk to my Siemens rep. I can ask about the model. Can you please provide me with that.

 

[Von]

I'm at a lime softening water treatment plant in Florida.

We have two 32 foot lime silos that use one Simens/Milltronics SITRANS-LU02 (2 channel) ultrasonic level transmitter to monitor their levels.
The device has a local display which alternates between the two channels, programmable relay outputs (for your indicator light), and 4-20ma. for the PLC/HMI.
The lime particles range in size from dust to near ping-pong ball sized and there has NEVER been any problem measuring this material with this device.

The silos are filled pneumatically from the top which generates a tremendous amount of dust internally during the process.

The transducers are mounted off center at the top of the silos aimed to the center of the silo (horizontal cross section)at 16 ft.
RWW

 

[robertmee]

How much dust is there? I think we've finally found something that will work in flour, but it's a little pricey...

I was talking to a fellow integrator and he's started using yo-yo probes in flour with very good success. It's basically a weight on a string coiled up on a small spindle driven by a DC motor. You run the weight down, it senses contact with the material through loss of tension in the string, grabs the level and pulls the weight back up. You set up the frequency that you want the weight measured. Would also work well for aggregate I imagine.

I've had alot of experience with ultrasonic, specifically milltronics (multirangers, airrangers, etc.) through the years in sidewall configuration application (square tanks) with dust, and IMHO, they don't work and are not worth the constant hassle of making adjustments to reduce the false echos. I can offhand remember at least 1/2 dozen installations where they were ripped out at great expense and replaced with guided radar.

 

[OZEE]

I was talking to a fellow integrator and he's started using yo-yo probes in flour with very good success. It's basically a weight on a string coiled up on a small spindle driven by a DC motor. You run the weight down, it senses contact with the material through loss of tension in the string, grabs the level and pulls the weight back up. You set up the frequency that you want the weight measured. Would also work well for aggregate I imagine.

We've used those yo-yos, too. They tend to be a huge maintenance issue over time. Plus they're not continuous level.

 

[Coachman]

Effector -Laser Sensor Works Great 4-20 ma output

O1D100 About $380.00 4-20 ma outputO1DLF3KG
Optical distance sensor
Quick disconnect

Visible laser light, protection class 2 laser
4-digit alphanumeric display

Measuring range 0.2...10 m
(Range referred to white paper 200 x 200 mm, 90 % remission)
Background suppression
> 10...19 m

 

[robertmee]

We've used those yo-yos, too. They tend to be a huge maintenance issue over time. Plus they're not continuous level.

They could be if you want to drop them on a 5 second interval

As for maintenance, Guided Radar probes tend to wear in two over time too. Maybe not in flour but certainly in anything abrasive like aggregate rock. We've used the Drexelbrook GRs in crushed rock applications and the probes last about 1.5 to 2 years before needing replacement. They are only stainless braided cables so the replacement costs aren't bad, but it is a hassle fishing them out of tanks. PM would go a ways in helping that, sort of like replacing your auto timing's belt, but I've had a hard time getting plant personnel to do that.

 

[robertmee]

O1D100 About $380.00 4-20 ma outputO1DLF3KG
Optical distance sensor
Quick disconnect

Visible laser light, protection class 2 laser
4-digit alphanumeric display

Measuring range 0.2...10 m
(Range referred to white paper 200 x 200 mm, 90 % remission)
Background suppression
> 10...19 m

We had problems with these too on a crushed rock application. Not so much with the rock itself but with fumes. When the tank emptied, the particular process allowed process fumes to back up into the tank. The laser read the fumes as level. Might not be an issue with the OPs application but something to be aware of.