Hi Guys,

Anyone have any experience in attempting to detect the presence of or amount of liquid vapour flowing through a (plastic) tube?
The vapour is basically a fine particle mist that will flow through the tubing and I can't find any sensors that are dedicated to this purpose. Some sensors use proximity sensors to detect the presence of gas bubbles or just to detect liquid flow.

Any advice regarding what sensors would be applicable to this purpose would be greatly appreciated.

(I have done some research into infrared, proximity and humidity so far - nothing promising yet)

 

Merely the presence?
It must be moving or the particles would fall out of the air stream.
Got anything on velocity, pressure, or temperature?
Does it have to be a plastic tube? Is the mixture allowed to go into a chamber and then resume its flow in another piece of tubing?

In other words, what are you trying to accomplish. This might not even be the best method.
Better questions get better answers.

 

Have you tried an opto-interrupter?

 

Merely the presence?
It must be moving or the particles would fall out of the air stream.
Got anything on velocity, pressure, or temperature?
Does it have to be a plastic tube? Is the mixture allowed to go into a chamber and then resume its flow in another piece of tubing?

In other words, what are you trying to accomplish. This might not even be the best method.
Better questions get better answers.

The vapour particles will be moving with the aid of a ventilator from which it would be possible to calculate the velocity (l/min) and probably the pressure too. The tube will always be see-through plastic and the flow will not be flowing into a chamber. It will just flow past the 'sensor', get to its destination, and then flow in a different direction.

 

Have you tried an opto-interrupter?

The opto-interrupter looks very interesting, thanks!!
Have you ever seen it used for a similar purpose? Is it based on infrared? And lastly, would it work through the plastic tubing if the distance between emitter and receiver was ~1"?

 

Have you ever seen it used for a similar purpose?

I worked with chemical analysis by color comparison in visible light through various colors of filter in 1972. That was clear tubing, but the colors were very important!

 

I worked with chemical analysis by color comparison in visible light through various colors of filter in 1972. That was clear tubing, but the colors were very important!

Hmmm interesting.
Do you an infrared sensor with an analogue output would give any useful feedback if used on either side of the plume?

 

Do you (think) an infrared sensor with an analogue output would give any useful feedback if used on either side of the plume?

The stuff I calibrated in 1972 created an analog output, but whether you should use infra-red?
That's what chemists do. I do analog design.

 

The opto-interrupter looks very interesting, thanks!!
Have you ever seen it used for a similar purpose? Is it based on infrared? And lastly, would it work through the plastic tubing if the distance between emitter and receiver was ~1"?

You can get opto-interrupters for IR range. Plastics and glass tend to be opaque to IR. You want to use quartz glass tubing for IR.

 

You want to use quartz glass tubing for IR.

I predict a negotiation on this point.

The tube will always be see-through plastic and the flow will not be flowing into a chamber. It will just flow past the 'sensor', get to its destination, and then flow in a different direction.

 

Hi Guys,

Anyone have any experience in attempting to detect the presence of or amount of liquid vapour flowing through a (plastic) tube?
The vapour is basically a fine particle mist that will flow through the tubing and I can't find any sensors that are dedicated to this purpose. Some sensors use proximity sensors to detect the presence of gas bubbles or just to detect liquid flow.

Any advice regarding what sensors would be applicable to this purpose would be greatly appreciated.

(I have done some research into infrared, proximity and humidity so far - nothing promising yet)

The only mist detector I met ever (in the carter of a fast marine engine) measured the level of light which was more or less obscured by the oil mist. BTW, ignoring the associated alarm costed around 1.000.000 USD in crankshaft replacement.

 

Vibration?Histle?