Some guidance, please.

[dracul]

Dear All,

First of all i am new to the forum, and i want to say hello to all !! , and i am looking for some guidance, i have a possible project that requieres measure two immiscible liquids in a tank, i just need to measure the height of the liquid, I know that you can use lasers and reflection to measure one liquid, but one in top of another ?

For example water and gasoline, and my question is if this is possible using lasers. Sorry to be so straigh forward but the real thing is that in my country there is no one to ask about lasers and possible applications.

Hope someone can point me to the right direction, just need the main idea in order to have somewhere to start investigating.

Thanks !!

 

[ryansoh3]

Since measuring distance using lasers involve the laser being reflected off a surface and returning back to the sensor, I don't think this is possible for gasoline and water.

However, if gasoline and water have distinctively different colors, using a specific wavelength might allow the sensor to discern water and gasoline.

Is measuring the height with a ruler out of the question? :thinking:

Cheers!

 

[dracul]

Since measuring distance using lasers involve the laser being reflected off a surface and returning back to the sensor, I don't think this is possible for gasoline and water.

However, if gasoline and water have distinctively different colors, using a specific wavelength might allow the sensor to discern water and gasoline.

Is measuring the height with a ruler out of the question? :thinking:

Cheers!

Dear ryansoh3,

Thanks for your reply, yes using a ruler is the thing that we are trying to avoid , the idea is to make an autonomous system that measure the liquids on real time avoiding the human interface.

Some fuels have an specific quantity of water on the mix, and during the storage period on a specific vessel the fuel and water have a small amount of separation, but during a long period of use and a lot of fuel rotation the quntity of water rise accumulating on the bottom of the tank and the water must be drain.

I believe that the fuel has a much different colour than water, but in the practical case, i must study it, maybe the water on the bottom has the same colour than the fuel or a very near one.

But, according to your answer, it can be done on certain conditions, last question, can you please point me, the type of laser i need to do it ?

Thanks !!

 

[ryansoh3]

I'm not so sure of a DIY setup using lasers to measure distance, but there are some devices that measure distance with the help of a laser.

They're not too expensive. ($100~$150)

Here's one:
Stabila 06300 Laser Measure Length, Area, Volume Type LD300 (Basic)

Here's a selection of laser distance meter:
Laser Distance Measuring Tools, Laser Tape Measurers, Electronic Tape Measures, Leica Disto, Stanley Fat Max, Laser Distance Finders

Fluke is an excellent multimeter and measurements manufacturer, and they make distance meters too. This one's about $200, but I'm sure it's worth the price.
Amazon.com: Fluke 411D Laser Distance Meter: Home Improvement

However, I doubt that they can measure the liquid height because if the fuel or water is transparent, the laser will simply go through it.

You can set a disk or something of a certain density so that it floats in between the fuel and the water. The disk then would be able to be measured for its height.

Cheers, and let us know of your progress!

 

[Atomicrox]

IMHO lasers aren't your best option.

You might be able to position a camera diagonally on the top of the tank and use very basic image recognition to identify the border between the liquids. After that some math should get you the heights

 

[dracul]

I'm not so sure of a DIY setup using lasers to measure distance, but there are some devices that measure distance with the help of a laser.

They're not too expensive. ($100~$150)

Here's one:
Stabila 06300 Laser Measure Length, Area, Volume Type LD300 (Basic)

Here's a selection of laser distance meter:
Laser Distance Measuring Tools, Laser Tape Measurers, Electronic Tape Measures, Leica Disto, Stanley Fat Max, Laser Distance Finders

Fluke is an excellent multimeter and measurements manufacturer, and they make distance meters too. This one's about $200, but I'm sure it's worth the price.
Amazon.com: Fluke 411D Laser Distance Meter: Home Improvement

However, I doubt that they can measure the liquid height because if the fuel or water is transparent, the laser will simply go through it.

You can set a disk or something of a certain density so that it floats in between the fuel and the water. The disk then would be able to be measured for its height.

Cheers, and let us know of your progress!

Thanks for your help but i am starting to believe lasers or diode lasers are not the best option

 

[dracul]

IMHO lasers aren't your best option.

You might be able to position a camera diagonally on the top of the tank and use very basic image recognition to identify the border between the liquids. After that some math should get you the heights

Thanks for your reply !!!, but as the fuel is darker than the water but lighther, so it possitions on top, how the camera will see the liquid/liquid inteface?

Thanks! !!

 

[Atomicrox]

Thanks for your reply !!!, but as the fuel is darker than the water but lighther, so it possitions on top, how the camera will see the liquid/liquid inteface?

Thanks! !!

Yeah, hadn't thought about that... That should make using lasers very hard as well, not to mention dangerous.

How about a sensor inside the tank? You could place it on the limit height and it'd go off when the water reaches that level. Not sure what kind of sensor to use, it has to be able to detect water but not fuel.

A more far fetched option is to leave the tank on a weight scale and use the total liquid height to compute volume and desity. With knowledge of the density of water and fuel you can compute the amount of water. Of course this would only work for a small moveable tank.