Soil Hopper level sensor

johnnysparks24 · Dec 29, 2005

We have a raised hopper at our plant that gets filled with soil. Our problem is that we can't see the hopper to see when its full as it is in a different room from the controls. Aside from measuring the soil going in, is there a simple way to monitor the material level in the hopper?

John

rsdoran · Dec 29, 2005

Probably the most common are bindicators;
http://www.bindicator.com/

The next would be ultrasonic;
http://www.sick.com/home/factory/catalogues/industrial/ultrasonic/en.html

Of course there are other ways but this should give you a start.

Sheldn · Dec 29, 2005

Avoid ultrasonics. I would suggest Radar depending on the granularity (ie it does not lump up) E+H or Siemens has good products. Siemens makes a unit for solids that is non-contact. Others such as E+H will probably recommend guided wave radar. Other and probably the most reliable would be to use load cells if the consistency / density of the material is consistent.

darrenj · Dec 29, 2005

How much info do you need? do you want to know level? or are you happy with knowiung it full,empty or getting low?

actually forget what i said..the way to go is ultrasonic or radar..I WAS thinking of level switches but with soil it would compact and get stuck between the probes causing false readings..

gbradley · Dec 29, 2005

Here's another option that works good.
Ultra-Mag™ Level Switch

Of course, If you've got sharp rocks in your soil they might not last, but I can tell you that they work great for Iron powder.

Binaural · Dec 29, 2005

Endress and Hauser make several high quality, inexpensive capacitive level probes. We have used several models on various sites around the world with minimal hassle. Have a look in particular at the level probes section; they offer a very useful selection matrix to quickly select what you are after based on the sensor type and material being measured.

sadanand_kulkarni · Dec 30, 2005

Guys,

First of all let me tell you I am not really expert in this field. I may be absolutely wrong. But what I feel like, can we do one thing? Instead of measuring the level we can have a load cell installed at the bottom of the hopper anbd calibrate the output of the load cell per to the level?

TConnolly · Dec 30, 2005

A load cell is a great way to measure the level in a hopper only when you have a consistent material. Unless this is a processed blended soil, it is not very likely to be consistent. Differing quantities of rocks, sand, and organic soil material as well as moist vs dry soil will probably make a load cell impractical.

sadanand_kulkarni · Dec 30, 2005

Yep, you are correct. The consistancy of material type is important for load cell in this type of application. Actually when I did this the material used to be the same.

Lancie1 · Dec 30, 2005

For 3 or 4 hundred dollars, you can install a cheap video camera above the bin, and a monitor in the other room. Then use the good old reliable human eyeball to determine when it is full.

johnnysparks24 · Dec 30, 2005

additional info / thanks for all input

The hopper has a convyor belt at the bottom the feeds soil out.

The soil is always a blended mixure but mostly peat moss. It's very light, farly dry and dusty.

We are in the process of automating the hole process. I want it to be a one buttun operation for each hopper.

The only thing I am stuck on is stoping the feed supply when the hopper is full. If it was a liquid a float wolud work, but its not.

A load cell may not work because of the convyor at the bottum. The hopper never has time to completly empty out, so again measuring may not work.

A simple, yet fairly inexpensive idea.

danw · Dec 30, 2005

Siemens has a rotating paddle, like the Bindicator.

A motor drives the shaft slowly, rotating the paddle, which extends into the hopper/bin/tank. When the material level gets high enough, the paddle hits it and halts the rotation of the shaft.

There's a sensitivity adjustment, via spring, if I remember.

Dry contact output for control. AC powered.

These things cost about $250 each. Simple and easy.

Sheldn · Dec 30, 2005

Tuning forks will work well for single point applications. Any single point device will need to be positioned so that is indicates the high level correctly since dry materials will have a tendency to pile up and not fill the tank like a liquid will. E+H, Siemens, Square D and others make this style and will cost you $200-400 depending on probe length, materials of construction etc...

Jimmie_Ohio · Dec 30, 2005

Alaric said:
A load cell is a great way to measure the level in a hopper only when you have a consistent material. Unless this is a processed blended soil, it is not very likely to be consistent. Differing quantities of rocks, sand, and organic soil material as well as moist vs dry soil will probably make a load cell impractical.

johnnysparks24 said:
The hopper has a convyor belt at the bottom the feeds soil out.

The soil is always a blended mixure but mostly peat moss. It's very light, farly dry and dusty.

We are in the process of automating the hole process. I want it to be a one buttun operation for each hopper.

The only thing I am stuck on is stoping the feed supply when the hopper is full. If it was a liquid a float wolud work, but its not.

A load cell may not work because of the convyor at the bottum. The hopper never has time to completly empty out, so again measuring may not work.

A simple, yet fairly inexpensive idea.

Based on the information contained in these two replies, especially the originator of the post, I vote for a load cell...

Because it is a solid with a varying angle of repose, and is probably piling differently, no "probe" will work, especially not a guided radar probe. There is no good point to look at.

I work with fly ash all the time. This application is tricky unless it piles up in a consistent shape.

TConnolly · Dec 30, 2005

I'm a really big fan of using load cells for hopper load determination. But I'm just not sure it will work for peat moss. The stuff is pretty inconsistent.

I'm throwing in with the bindicator paddle wheel. You may need two or more of depending on the hopper size because of uneven peat moss distribution. However, the paddle wheel is not going to give you level indication, it will only provide point indication.

Maybe the best solution will be a combination. The load cell will certianly tell you when the hopper level is getting low but it won't provide you any kind of hopper overflow guarantees. If you have a wide hopper level range in which to work using it in conjunction with a paddle wheel may render an acceptable solution, but it won't give you an iron clad level reading.

How big is this hopper and what kind of tolerance are you requiring?

Soil Hopper level sensor

johnnysparks24

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rsdoran

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