Need level sensor to measure level of ravioli sunken in water

JaxGTO · Dec 15, 2015

We have a customer that uses a diafram pump to send water and ravioli to a hopper. The hopper then has a cogged belt that pulls them out from the bottom and into a filler.

They would like to control the level in the hopper. but the hopper has water with ravioli sunken to the bottom and the level they want is the ravioli. The water varies as much as the ravioli level.

Was thinking of a waste water type probe that can measure the solids rather then the water. Anybody know of a sensor that may work for this?

Here is a link to a video of the process. The hopper was running low that day.

Thanks, Jack.

WARNING. VIDEO IS LOUD
http://youtu.be/WjLYZF2e5Ak

Doug-P · Dec 15, 2015

How about a fish finder?

http://www.lowrance.com/en-US/Products/Sonar/

m_turk · Dec 15, 2015

This is why I love this job...

The level of ravioli, lol...

But sorry, I don't have an idea beside the "logical" fish finder

You guys just made my day, even though no one was joking...

(if there was a bigger tank and a slower proces, maybe the difference between a pressure probe and a ultrasonic level could give you the ravioli-water ratio, but from how it looks and the close density of ravioli and water, I don't actually think it would work..)

osmanmom · Dec 15, 2015

load cell

redbarron55 · Dec 15, 2015

If you keep a constant level and use a load cell then you can have a relative density that would be related to the amount of ravioli or the Ravioli index.
We use a similar method to judge the thickness of sludge in a tank. Too close to the weight of just water and the "sludge" is very thin.
Higher density thicker sludge.

ASF · Dec 15, 2015

The load cell isn't a bad idea. Although, the fact that the level varies complicates it - you'd have to compliment it with a distance-type level sensor (like an ultrasonic) and then do some mathematical black magic to correlate the level and weight readings into a % water vs % ravioli reading.

And yes, I did not wake up today expecting to give any thought to the best way to measure ravioli. The fish finder is a stroke of genius!

Saffa · Dec 16, 2015

Endress do an interface level sensor which is basically a submerged ultrasonic level sensor. We use them for detecting sludge interface for clarifiers in wastewater. Sensor is the Turbimax CUS71D.

The "product" would need to self level and all be at the bottom for this to work though. You can probably get a loan unit for a trial.

Tom Jenkins · Dec 16, 2015

If you don't need precise control you may be able to use capacitance based prox switches mounted at intervals. You should be able to adjust the sensitivity to pick up the ravioli and ignore the water.

The sludge blanket detectors Saffa suggested would undoubtedly work, but I believe the probe face must always be submerged. If your water level varies as you indicate the mounting would have to compensate. They are a little expensive as well.

jraef · Dec 16, 2015

But what's the end goal of the sensor information? Are you going to try to maintain an optimum ravioli density? Or are you wanting to determine if there are too many ravioli in the hopper for the belt to function? Or are you wanting to maximize the hopper level to avoid spilling? I would think unless you can easily overload that belt, the ravioli density would be somewhat irrelevant, no? What I'm getting at is that someone might be over thinking this a bit, when all that really matters is avoiding spilling over the top of the hopper. Any level sensor could work for that.

lunenburger · Dec 16, 2015

We have the exact same issue with potatoes under water.
We have tried many types of interface probes, but the cloudy water makes it too inconsistent.
The best instrument we have found is a yo-yo bindicator. This gives you an analog level every few seconds.
check them out here:
http://bindicator.com/products/yo-yo-series-level-indicator/

Saffa · Dec 16, 2015

Tom Jenkins said:
I believe the probe face must always be submerged. If your water level varies as you indicate the mounting would have to compensate. They are a little expensive as well.

Tom is right on both counts. If the level changes substantially then this could be a problem. If there's a minimum water level, and the pesky pasta doesn't get any higher than this then you'll be fine. But if the ravioli level can be higher than minimum water level then you'll have an issue.

And yes they're not cheap... about $6k NZD last time i checked.

shooter · Dec 17, 2015

on top of the tank, make a hoist, with a float on it, and lower it until the tension on the wire is zero.
as float use a pyramide,
i have used a wooden stick resting on top of (fish), when the stick was gone, the tank needed refill from tank.
as pump a vacuum system is used to prevent damage on the fish.

JaxGTO · Dec 17, 2015

All great ideas thanks. Still looking at sensors and floats. But I the the Yo-Yo if only so I can tell the customer 'Yo-Yo it's a Yo-Yo"
Thanks all...Jack.

RET · Dec 17, 2015

lunenburger said:
We have the exact same issue with potatoes under water.
We have tried many types of interface probes, but the cloudy water makes it too inconsistent.
The best instrument we have found is a yo-yo bindicator. This gives you an analog level every few seconds.
check them out here:
http://bindicator.com/products/yo-yo-series-level-indicator/

I like it.

Need level sensor to measure level of ravioli sunken in water

JaxGTO

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