Humidity sensor for environments full of alcohol vapour? - Page 1
Forum section: electronics / projects

author: miceuz
author_rank: Frequent Contributor
timestamp: November 10, 2016, 10:52:55 am
content: Can someone suggest a relative humidity sensor that could be used in an environment full of alcohol vapour and will not degrade over time? I'm not looking a long term solution, just something that could give us reliable readings in our design prototype.We are designing a washing system that uses Isopropyl alcohol, while the alcohol works well, it makes water contained in the air to condense on the surface being washed as it evaporated. I want to measure and monitor this, find counter-act measures and them measure again.I have stumbled on this, but not sure if there are sensors that result from this study there somewhere. Almost all high end humidity sensors claim to be capacitive:http://www.vaisala.com/Vaisala%20Documents/Scientific%20papers/chemical_interference_testresults_h180r.pdf

author: DTJ
author_rank: Super Contributor
timestamp: November 10, 2016, 01:20:31 pm
content: Perhaps email the people at Sensirion and ask them.

author: LaserSteve
author_rank: Super Contributor
timestamp: November 10, 2016, 06:59:31 pm
content: Talk to the folks at CO2Meter.com and see if their near IR optical sensor will discriminate between the two hades. Otherwise your starting to look at very expensive techniques bAsed on mass separation or far IR optical methods.Steve

author: xygor
author_rank: Regular Contributor
timestamp: November 10, 2016, 07:41:51 pm
content: Quote from: LaserSteve on November 10, 2016, 06:59:31 pmI have never used or heard of hades. Is that some kind of FET? I heard hades have gates.

author: xygor
author_rank: Regular Contributor
timestamp: November 10, 2016, 07:47:17 pm
content: Maybe forum member Cerberus can help here.

author: miceuz
author_rank: Frequent Contributor
timestamp: November 11, 2016, 07:52:29 pm
content: Thanks all for suggestions, I guess I'm out of luck on this one

author: Tomorokoshi
author_rank: Super Contributor
timestamp: November 12, 2016, 02:00:02 am
content: I don't use these, but depending on your budget something like this may be what you are looking for:http://www.epluse.com/en/products/humidity-instruments/industrial-humidity-transmitters/ee300ex/With the alcohol vapor, will that area need to be classified as a hazardous location? If it is, you may need to use Intrinsically Safe devices.Search Google for "hazardous location humidity sensor".Information about hazardous location products and design is available at:http://www.rstahl.com/products-and-systems.htmlhttp://www.pepperl-fuchs.us/usa/en/index.htmhttp://www.intertek.com/hazardous-locations/

author: Someone
author_rank: Super Contributor
timestamp: November 12, 2016, 02:19:06 am
content: Quote from: miceuz on November 10, 2016, 10:52:55 amIf your atmosphere has known components that you are controlling then consider thermal conductivity measurement:https://www.electronics-cooling.com/2003/11/the-thermal-conductivity-of-moist-air/https://en.wikipedia.org/wiki/Thermal_conductivity_detectorThey're used in several precision gas concentration instruments when you're working over a known range with only 1 or 2 variables.

author: _Wim_
author_rank: Super Contributor
timestamp: November 12, 2016, 09:07:29 am
content: Check these guys out:http://www.michell.com/uk/category/process-analyzers.htmA chilled mirror dewpoint meter would maybe will help you (very accurate), but be prepared for some $$$

author: _Wim_
author_rank: Super Contributor
timestamp: November 12, 2016, 09:11:19 am
content: This one might be ideal for a test setup:http://www.michell.com/uk/products/optidew_vision.htm