Sensor for reading water in steam environment

[drbitboy]

... the sensor when not placed over the tube gives stable readings. the only thing we can figure out is that the steam in the tube being seen as the water level. as it goes to the top of the tube, the sensor no longer sees the steam.

by "steam," do you mean small, visible, liquid water droplets above the water level i.e. i.e. the water/vapor interface?

by "it," do you mean the water level?

by "no longer sees the steam," do you mean the sensor gives reasonable values?

 

[mylespetro]

Guided wave would be my recommendation as well. Vega has some great sensors, even ones where you can cut the probe to length as required.

 

[boardmaker]

In our boiler Deaetor tank, we use guided wave. It's basically the same process you're looking at.

 

[g.mccormick]

https://www.omega.com/en-us/level-m...-sensors/float-sensors/lvr500-series/p/LVR516

 

[g.mccormick]

https://www.automationdirect.com/ad...a-_controllers/radar_level_sensors/gwr-1600-p

With the following probe (450mm) that you can cut down to 16" need.
https://www.automationdirect.com/ad..._sensors_-a-_controllers_accessories/gwr-p450

 

[JesperMP]

[..] heated to 200 degrees F.

So not boiling, but still higher than what most electronic sensors are rated for.

we have been using a turck rod sensor with a magnetic float which has now gone bad after only a few months [..]

Was this rated for high temperature ? If not, that would my suggestion.

this is not a pressurized vessel.

Then instead of the float you can measure pressure. There are sensors that are intended for being dropped into a tank and report the level based on the pressure. Here is a high-temperature one:
https://www.ato.com/high-temperature-level-sensor-20m

 

[drbitboy]

Eureka

I suspect guided wave is the long-term non-contact solution, but I wonder if hose spraying water slowly on the outside of the level tube will allow the ultrasonic to yield good values again.

There will be a small difference (~3% max, so up to maybe half an inch over 18") in the level between the tank and the tube, which has probably always been true to a smaller degree* but unnoticed.

* smaller temperature difference

 

[robertmee]

https://www.automationdirect.com/ad...a-_controllers/radar_level_sensors/gwr-1600-p

With the following probe (450mm) that you can cut down to 16" need.
https://www.automationdirect.com/ad..._sensors_-a-_controllers_accessories/gwr-p450

Only good to 212 deg F. I'd be leery. Also, how contaminated does this water get? You're dipping a product, is there any particulate that is left behind? These guided radar type in a closed diameter of 1 1/2" may have issues over time with buildup and if the dielectric of the solution is changing.

 

[robertmee]

https://www.omega.com/en-us/level-m...-sensors/float-sensors/lvr500-series/p/LVR516

Only good to 185 deg F. But otherwise, what I was thinking. Never used one personally, do they have issues with the rod getting contaminated and the float getting stuck? The OP said this is a dipping tank. Would be concerned with crud left as a residual from the process.

 

[James Mcquade]

drbitboy,

when i refer to steam, i mean the vapor coming off the water, like what you see
on the highway after a quick shower.
by it, i mean the vapor going up the tube. again, like the steam you see on the highway after a quick shower.
when the steam dissipates, the sensor gives stable and accurate readings.
james

 

[drbitboy]

drbitboy,

when i refer to steam, i mean the vapor coming off the water, like what you see
on the highway after a quick shower.
by it, i mean the vapor going up the tube. again, like the steam you see on the highway after a quick shower.
when the steam dissipates, the sensor gives stable and accurate readings.
james

Okay, so wet steam or aerosol. So you, and presumably the ultrasonic sensor, are seeing the liquid water droplets.

Dry steam as a vapor is transparent to visible light.

Try the hose; if you can cool the water in the tube, the droplets should dissipate and the ultrasonic might work again.

 

[parky]

What we have used on our CIP tanks (caustic)are the endress & Hauser hydrostatic (pressure sensors), these would need to be in the bottom of the tank though, they certainly work at 90 Deg C without problems ours were calibrated in litres & went from 0-4000 litres, there is an area (very small) at the bottom of the tank due to the convex shape with bottom exit valve so mounted about 3" up on the domed bottom.
We converted some other CIP tanks from high/low level rod sensors to the above ones just required a mounting boss cut & welded to the bottom of the tank (we actually used an inserted threaded flange) so the diaphram sat above the bottom of the tank due to the possibility of some accumulation of product may occur at the bottom being a flat bottom tank.

 

[James Mcquade]

thank you for the replies,
james