Off-subject : Calibrating Belt Scales

HoldenC

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Sep 2012
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I know this is very far off subject, but was hoping someone here could lend a hand.

I have been asked to start calibrating belt scales for the company I work for. I would need to travel to several locations to do this.

We use Thermo Ramsey belt scales. I have read the manual and understand it all. I am just confused about what weights I need, and how to attach them. I cant seem to find much information on this part of it.

Thanks in advance.
 
Hi, what type of product is on the belts? I worked at a cement plant that used a lot of weigh feed belts, and for calibrating we had to remove the product from the part of the belt that was in between the load cells and weigh it up on a separate scale. So if the belt readout said there was 180 lbs of product per second moving on the belt into the mill, then in a 2 foot section there would have to be X lbs calculated with the belt speed which we had a readout for and we could actually measure with a handheld device. So to continue, we got little shovels and buckets and removed the slag, limestone, clinker whatever was on that 2 foot section and weighed it. Of course we worked with an outside tech that serviced all of our weigh feed belt equipment, but sometimes we did it on our own. Not very many electricians so we didn't have a lot of time to do these calibrations. Hope this helps.
 
These scale will have coal moving across of them headed for steel mills.

These belt scales offer a "material" calibration , which is pretty much what you described, however that isnt possible for this scenario. I wish it was though. That seems like it would make my job easier.

Ive called a couple scale companies, but they only offer to calibrate them for us. So no help there.....which I cant blame them.
 
Can you somehow push a container or other suitable vessel into the stream of material that flows off the conveyor ? And can you remove the container/vessel again, must be relatively fast.
If you can, you can use that to calibrate the belt weigher.
Maybe you have to make a special chute that can be moved quickly in and out of the material stream.
The bigger the container/vessel is relative to the flow of the material, the more accurate will the measurement be.
 
I am just confused about what weights I need, and how to attach them. I cant seem to find much information on this part of it.

Not the same as your brand but most are something like this that I have seen https://www.youtube.com/watch?v=4oteO_T60p4

You will enter in the weight amount that you are hanging and dont put it on the conveyor it hangs on the load cells this was you can keep the conveyor in the normal state of run, I would recommend that your company have a outside service company do one first and you work with them then you can do it on your own
 
Not the same as your brand but most are something like this that I have seen https://www.youtube.com/watch?v=4oteO_T60p4

You will enter in the weight amount that you are hanging and dont put it on the conveyor it hangs on the load cells this was you can keep the conveyor in the normal state of run, I would recommend that your company have a outside service company do one first and you work with them then you can do it on your own

I already calibrate a Siemens belt scale we have and they have a bracket on them, made just for holding special weights. Pretty straight forward. Im not sure what the weights would look like that I would need for these. Looks like it may have to hang off the roller/idler.
 
Im not sure what the weights would look like that I would need for these. Looks like it may have to hang off the roller/idler.
Can you use the Siemens weights? I dont think they are anything special.... I used buckets of water and rope in some load cell calibration I have done in the past, you just need to know the weight and make sure its close to center on both cells (odds are there two ~ one each side) hang a given weight close to the PV in the middle and set your span
 
Im not sure what the weights would look like that I would need for these.


We typically use weights like these for calibration purposes:



calibration-weights-500x500.jpg



Available in standard sizes. Where I live we think in metric units, so we would typically use one or more standard weights of 1kg, 5kg, 10kg, 20kg depending on the application at hand.
 
Can you use the Siemens weights? I dont think they are anything special.... I used buckets of water and rope in some load cell calibration I have done in the past, you just need to know the weight and make sure its close to center on both cells (odds are there two ~ one each side) hang a given weight close to the PV in the middle and set your span

The Siemens weights will not work on my set-up. The Siemens weights are shaped like "J's". They just hang over a bracket that is welded to the idler on top of the load cells. I had considered making a similar bracket and welding it on. I cant see a reason why this wouldnt work. I would just need to re-zero the scales.
 
We typically use weights like these for calibration purposes:



calibration-weights-500x500.jpg



Available in standard sizes. Where I live we think in metric units, so we would typically use one or more standard weights of 1kg, 5kg, 10kg, 20kg depending on the application at hand.


I have seen these weights like this when researching what I need. What do you use those weights for ?
 
I have seen these weights like this when researching what I need. What do you use those weights for ?

I have used them also... its just a known weight that you are looking for, I worked with a lot of webbing so we would use ropes tied to the handles on these, run the rope through the rollers and the result would be a known weight pulling/pushing on the cells and it should equal x newtons , but when some dumb a$$ uses it as a door prop and you cant find the weights then you just need to use anything, just weight it on a calibrated scale then you know what you have, we had scales everywhere

Yours should be easier with a 'modern' scale, I would have two weights and verify both and zero... maybe a high and low of your PV
 
Exactly. We use these weights a lot because many of our products include weighing indicators which need to be calibrated in order for our clients to be allowed to use the machines for dosing and weighing applications. For that use we are required to use calibrated weights, hence our need for those weights. A bucket of water would not do in our case. We have plenty of these weights in the company, and even our weights need to be re-checked on a regular basis in order for us to be allowed to use them for calibration purposes. Other uses have less strict regulations.
 
We typically use weights like these for calibration purposes:



calibration-weights-500x500.jpg



Available in standard sizes. Where I live we think in metric units, so we would typically use one or more standard weights of 1kg, 5kg, 10kg, 20kg depending on the application at hand.

Would you happen to know where I can purchase these from ? Or, at least what this style is called ? I like that they have a handle and would make tying them up very easy.

I have used them also... its just a known weight that you are looking for, I worked with a lot of webbing so we would use ropes tied to the handles on these, run the rope through the rollers and the result would be a known weight pulling/pushing on the cells and it should equal x newtons , but when some dumb a$$ uses it as a door prop and you cant find the weights then you just need to use anything, just weight it on a calibrated scale then you know what you have, we had scales everywhere

Yours should be easier with a 'modern' scale, I would have two weights and verify both and zero... maybe a high and low of your PV

The scale system I i will mostly be dealing with only has a zero and a place to enter 1 known weight. It makes it easier than I can go back and see how much weight the scale company used last when calibrating them.
 

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