Sensors

h2ophotopro · 16th March 2005, 22:55

How many of you guys have had issues with the sensors being EXTREMELY sensitive to moisture. 3 Insp divers went to Fiji and 2 of them had nothing but problems with their sensors from the humidity. This has been real apparent in many locales with a lot of our Rebreather divers.

I think there needs to be a new design so help keep the moisture to a limit and also to restrict any water that enters the system from coming into contact with the sensors.

This has been the only draw back to the Insp...sensitive sensors!!

Diver · 16th March 2005, 23:02

Hi Mike,

Have you read this article about a small addition / modification to the Inspi.
Seems that this problem has been ongoing for a while as this article dates
back to Jan 2002.

Diver Daves Inspiritation Modification.

ATB & Safe Diving

TC

**nigelh** · 16th March 2005, 23:08

Quote: (Originally Posted by h2ophotopro)

This has been the only draw back to the Insp...sensitive sensors!!

Are you sure?
As I see it the loop runs at 100% humidity from the end of the prebreath to the end of the dive.

***caveseeker7*** · 16th March 2005, 23:19

Quote: (Originally Posted by nigelh)

Are you sure?
As I see it the loop runs at 100% humidity from the end of the prebreath to the end of the dive.

The problem is not the 100% hummidity, but the space where condensation occurs. On the Inspiration quite some of it, especially in warm water or long dives, occurs where the cells are. The water droplets then influence the sensor readings as the partially block the sensor's membrane. IIRC, especially the #2 sensor is prone to that.

ROB DAVIE · 16th March 2005, 23:20

Folks,

I can only speak from my own experience. The first long term experience I had with the Turtle was a trip to the Galapagos (Darwin's Arch). We had 24 units, and we dove like crazy for 10 days. In that time we only had one bad sensor, and a couple of trashed AutoAirs.

Since then I've had good reliability with the exception of the time I broke a wire while working on the hat. My fault entirely.

Just my PPO2's worth.

Rob

h2ophotopro · 16th March 2005, 23:31

Well I know that in Fiji it was extremely humid and we had a lot of problems with condensation building up and the sensors giving cell warnings and cell failures. Once we opened the units, dried off the sensors and let the head dry out for a few, all was well. But to have to open up the head in between dives and let it dry out is utterly ridiculous.

yes Stefan, the #2 cell is the biggest problem.

***caveseeker7*** · 17th March 2005, 00:47

I discussed that subject with Joe R a little while ago, he sees considerable less condensation in the head in cold water as much of it condensates in the down tube and ends up in the bottom of the scrubber.
That's why APD insists that the R-22BUDs are used with the coated membrane.

Different Rebreather designs have been dealing with that problem differently.
The Cis split the gas path, so a smaller volume of gas and moisture went across the sensors. It also had a sponge trap for moisture, and finally manual injection went across the sensor faces. That's probably where Dave got the idea for his modification.

The MK series also split the gas path, and and placed the sensors in the center of the donut where temps are high. Most condensation occurs when gas comes out of the scrubber and hits the dome.

On the PRISM most of it also occurs along the bucket after the gas exits the basket. It also has a foam trap in the sensor space. There is some condensation, but fairly little.

The Meg has a chammy in the sensor holder, am not sure if or what other measures are taken to avoid wet sensor faces. Can't remember any complaints, so it seems Leon did his homework in that regard.

h2ophotopro · 17th March 2005, 01:27

Thanks again Stefan. I want to get this taken care of so I dont run into any other scenarios.

16th March 2005, 22:55	#1 (permalink)
h2ophotopro Photo Pro Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Feb 2005 Location: Woodland Hills, CA Posts: 161	Sensors How many of you guys have had issues with the sensors being EXTREMELY sensitive to moisture. 3 Insp divers went to Fiji and 2 of them had nothing but problems with their sensors from the humidity. This has been real apparent in many locales with a lot of our Rebreather divers. I think there needs to be a new design so help keep the moisture to a limit and also to restrict any water that enters the system from coming into contact with the sensors. This has been the only draw back to the Insp...sensitive sensors!! __________________ Mike Luzansky H2O Photo Pros Underwater Photo & Video Visit our New Showroom 2429 W. Coast Hwy, #101 Newport Beach, CA 92663
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16th March 2005, 23:02	#2 (permalink)
Diver Top Geek Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jan 2005 Location: Vancouver, Canada Posts: 13	Hi Mike, Have you read this article about a small addition / modification to the Inspi. Seems that this problem has been ongoing for a while as this article dates back to Jan 2002. Diver Daves Inspiritation Modification. ATB & Safe Diving TC
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16th March 2005, 23:08	#3 (permalink)
nigelh New member Current Rebreather/s: Inspiration Vision Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Mar 2005 Location: Brighton, Sussex, UK Posts: 873	Quote: (Originally Posted by h2ophotopro) This has been the only draw back to the Insp...sensitive sensors!! Are you sure? As I see it the loop runs at 100% humidity from the end of the prebreath to the end of the dive. __________________ nigelh
(Online)

16th March 2005, 23:19	#4 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,535	Quote: (Originally Posted by nigelh) Are you sure? As I see it the loop runs at 100% humidity from the end of the prebreath to the end of the dive. The problem is not the 100% hummidity, but the space where condensation occurs. On the Inspiration quite some of it, especially in warm water or long dives, occurs where the cells are. The water droplets then influence the sensor readings as the partially block the sensor's membrane. IIRC, especially the #2 sensor is prone to that. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
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16th March 2005, 23:20	#5 (permalink)
ROB DAVIE Administrator Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: HOUSTON, REPUBLIC OF TEJAS Posts: 1,120	Sensors Folks, I can only speak from my own experience. The first long term experience I had with the Turtle was a trip to the Galapagos (Darwin's Arch). We had 24 units, and we dove like crazy for 10 days. In that time we only had one bad sensor, and a couple of trashed AutoAirs. Since then I've had good reliability with the exception of the time I broke a wire while working on the hat. My fault entirely. Just my PPO2's worth. Rob __________________ "CC Rebreathers will become a viable part of tech diving WHEN PIGS FLY!!"--GI3
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16th March 2005, 23:31	#6 (permalink)
h2ophotopro Photo Pro Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Feb 2005 Location: Woodland Hills, CA Posts: 161	Well I know that in Fiji it was extremely humid and we had a lot of problems with condensation building up and the sensors giving cell warnings and cell failures. Once we opened the units, dried off the sensors and let the head dry out for a few, all was well. But to have to open up the head in between dives and let it dry out is utterly ridiculous. yes Stefan, the #2 cell is the biggest problem. __________________ Mike Luzansky H2O Photo Pros Underwater Photo & Video Visit our New Showroom 2429 W. Coast Hwy, #101 Newport Beach, CA 92663
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17th March 2005, 00:47	#7 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,535	I discussed that subject with Joe R a little while ago, he sees considerable less condensation in the head in cold water as much of it condensates in the down tube and ends up in the bottom of the scrubber. That's why APD insists that the R-22BUDs are used with the coated membrane. Different Rebreather designs have been dealing with that problem differently. The Cis split the gas path, so a smaller volume of gas and moisture went across the sensors. It also had a sponge trap for moisture, and finally manual injection went across the sensor faces. That's probably where Dave got the idea for his modification. The MK series also split the gas path, and and placed the sensors in the center of the donut where temps are high. Most condensation occurs when gas comes out of the scrubber and hits the dome. On the PRISM most of it also occurs along the bucket after the gas exits the basket. It also has a foam trap in the sensor space. There is some condensation, but fairly little. The Meg has a chammy in the sensor holder, am not sure if or what other measures are taken to avoid wet sensor faces. Can't remember any complaints, so it seems Leon did his homework in that regard. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
(Offline)

17th March 2005, 01:27	#8 (permalink)
h2ophotopro Photo Pro Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Feb 2005 Location: Woodland Hills, CA Posts: 161	Thanks again Stefan. I want to get this taken care of so I dont run into any other scenarios. __________________ Mike Luzansky H2O Photo Pros Underwater Photo & Video Visit our New Showroom 2429 W. Coast Hwy, #101 Newport Beach, CA 92663
(Offline)

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