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Topic: Measuring flow rate of a milking machine (Read 827 times) previous topic - next topic

sasithnuwantha

I want to create a flow meter for a milking machine which works on vaccume.I tried hall effecct flow meter senaor, but due to vaccum effect the senaor rotatea even when without milk flow. Alao i doubt that full flow is needed to get the correct results .

Can please anyone suggest me a good method??

robtillaart

I would place load cells under the bucket and weight the amount of milk. (1)

or you could measure the weight of the cow (goat) as it should become lighter.  (2)

Think (1) is the better of the 2.
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

Paul_KD7HB

In Dad's dairy, the milk traveled through transparent plastic tubes and came in pulses. Each pulse filled the tube for a time.

Use a LED and a light sensor to measure the time the milk is obscuring the LED. You can measure the inside area of the tube. That times to time the light is obscured will give you the milk flow.

Will that work for you?

Paul

cedarlakeinstruments

I've been working on a niche type of fluid dispensing machine for a few week and weighing the dispensed fluid was my solution to knowing when to stop.

I was concerned that the type of fluid might cause clogs in a standard paddlewheel flow sensor, so I fabricated an external weigh scale using a 2kg load cell and an HX711 breakout and it works very well. The load cell is very sensitive and since I'm using a Raspberry Pi instead of an Arduino, I had to do some specific data processing to deal with timing interruptions.

The system works well enough that I'm considering marketing my weight platform as an off the shelf product.
Electronics and firmware/software design and assistance. No project too small

Paul_KD7HB

I've been working on a niche type of fluid dispensing machine for a few week and weighing the dispensed fluid was my solution to knowing when to stop.

I was concerned that the type of fluid might cause clogs in a standard paddlewheel flow sensor, so I fabricated an external weigh scale using a 2kg load cell and an HX711 breakout and it works very well. The load cell is very sensitive and since I'm using a Raspberry Pi instead of an Arduino, I had to do some specific data processing to deal with timing interruptions.

The system works well enough that I'm considering marketing my weight platform as an off the shelf product.

I don't see how this relates to the OP wanting to measure milk flow.

You do not address the problem milk creates in ANY mechanism. As you are aware, milk is an animal product and as such contains bacteria. The bacteria love to find spots to grow in any place in any machine. Fresh milk is also hot and when it cools any amount, the fat content begins to precipitate.

All this means the mechanism must be hot and chemically sterilized at least once per day. Any residual material will promote bacteria.

Your process apparently does not have these problems.

Paul

cedarlakeinstruments

My process actually has very similar problems since it's moving fluids containing biologic materials. That's exactly the reason I chose a weight sensor -- the nasties cause problems with paddlewheel flow sensors!
My fluid aspiration is also done by vacuum: to avoid contamination, I pull a vacuum on a sealed container (that is weighed to verify flow) and that vacuum pulls the fluid in through another tube.

Using a flow sensor has the issues you mention, although in my case I was mainly concerned with clogs.The point of suggesting weight as a mechanism is that it can be completely decoupled from the fluid path and the sanitary issues don't apply.

He could either (a) weigh the final container that the milk is going to be in, or (b) transfer it to an intermediate container that is weighed, then have another pump system to transfer it out.

@OP:
If the only issue you have with the flowmeter is that air is also being measured, you could add a pressure sensor on the line. That should allow you to see the difference between milk & air and you can ignore the counts when milk is not flowing.
Electronics and firmware/software design and assistance. No project too small

Paul_KD7HB

My process actually has very similar problems since it's moving fluids containing biologic materials. That's exactly the reason I chose a weight sensor -- the nasties cause problems with paddlewheel flow sensors!
My fluid aspiration is also done by vacuum: to avoid contamination, I pull a vacuum on a sealed container (that is weighed to verify flow) and that vacuum pulls the fluid in through another tube.

Using a flow sensor has the issues you mention, although in my case I was mainly concerned with clogs.The point of suggesting weight as a mechanism is that it can be completely decoupled from the fluid path and the sanitary issues don't apply.

He could either (a) weigh the final container that the milk is going to be in, or (b) transfer it to an intermediate container that is weighed, then have another pump system to transfer it out.

@OP:
If the only issue you have with the flowmeter is that air is also being measured, you could add a pressure sensor on the line. That should allow you to see the difference between milk & air and you can ignore the counts when milk is not flowing.
You are doing exactly what dairies do. They have to weigh the milk from each cow, each milking, to ascertain the health of the cow. The value of the cow is how much milk she produces and the butterfat of that milk. I am sure the OP is doing the same, if he really has a dairy.

Paul

Paul

Deous

I want to create a flow meter for a milking machine which works on vaccume.I tried hall effecct flow meter senaor, but due to vaccum effect the senaor rotatea even when without milk flow. Alao i doubt that full flow is needed to get the correct results .

Can please anyone suggest me a good method??
I have seen ultrasonic flow meters that can be mounted outside of the flow-pipeline.
I'm not sure if they work with milk but they do with water.
They are not cheap but also not too expensive.

https://en.wikipedia.org/wiki/Ultrasonic_flow_meter

INTP

Why would you need real-time flow rate?
After each completion, average flow rate would simply be volume divided by time.
I don't see this need for instantaneous flow rate, so please explain how that information would be used, what it would control, etc.
It sounds like a case of just wanting to measure something for the same of measuring something. 'Not everything that counts can be measured, and not everything that can be measured counts'.

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