R22 ???

AD_ward9

Yes, all cells we trialled are commercially available and have been for 5 years.
Alex

Faceless

Now that's VERY interesting, right now i'm considering buying a rebreather, so sensor replacement issue is definitely not least among other maintenance means to me.

Is this a correct link to producer of these sensors (correct me if I'm wrong):
http://www.insovt.ru/o2sensors/compatibles.php

I'm russian native, so I may translate text from the page if you like.

AD_ward9

The Insovt DK-32 (ДК-32) was one of the sensors included in the 5 year trial we carried out.

For those unfamiliar with the company, Insovt is a St Petersburg company with a long history of supplying Russian process industries, the Russian Navy and in diving in Eastern Block countries.

The ДК-32 is a high performance sensor, filled with silicone oil. The response time is 20 to 30 seconds, and was measured at 25 second for the batch we tested. The sensor is rated to produce 5mV in air, and measured at 4.999mV. It has a hydrophobic membrane fitted and a novel means to prevent pressure lifting the sensor membrane.

At the beginning of the trial the DK-32 sensors were tested and found to produce 5mV in air (as specified), but the temperature compensation was not functioning. Considerable care was taken to ensure all measurements were taken at the same temperature (21.0C). Variation between the sensors when new was less than 20mV.

At the end of the 5 year period, no difference was noted between sensors that had been stored and those in use. All sensors were still operational, all produced the same output voltage in 100% O2 and in air as they did at the start of the trial. There was no corrosion visible except slight corrosion of the contacts.

The ДК-32 sensor seems accurate to within 1% when the temperature and pressure are compensated properly. Note that the temperature compensation build into the ДК-32 does NOT function correctly and can give a 2%/C change in output value for the batch we tested. This could be remedied, but there is another issue.

During the HAZOP Study in the O.R. Project using the formal model of the rebreather a serious problem was found using the Insovt sensors: if the sensor response is more than 10 seconds, and the diver is using a set point of 0.4 or below, as is required for commercial use, then the diver can ascend fast enough for the PPO2 to drop below 0.12, causing loss of consciousness. This hazard was considered serious enough by the HAZOP Study Group to rule out all sensors responding slower than 10s (to 90% of final value).

I will post some pictures of the Insov sensors later today: I have some here in Scotland fitted to a rebreather.
Edit: Pictures added.

Cheers

Alex

Attached Images

	Insov D32_174.JPG (61.7 KB, 103 views)
	Insov D32_174b.JPG (50.7 KB, 101 views)
	Insov D32_174c.JPG (67.4 KB, 102 views)
	Insov D32_174f.JPG (47.7 KB, 100 views)

Micko

mark i have nad the same prob as you details the same on apecs it has to cells

SINUS

Hi Alex,

Thanks for posting the rare russian made o2 sensors. May I know what the costs like compare to Teledyne's sensor.


Thanks in advances,

Wei Lan

__________________
"Silence Is Always Beautiful"

AD_ward9

Insovt sensors are cheaper than Teledyne's even though they are potted, filled with silicone oil (you can see the bubbles in the pictures I posted). Though we really like the quality, I do emphasise, the Insovt sensors are unfortunately not suitable for rebreathers due to the response time.

I would suggest you look at AI (www.aii1.com), in particular the PSR-11-33 range, especially if price is an issue. The reason I say this is that Teledyne have anti competitive measures to prevent companies competing with AP Diving, that includes adverse pricing and refusal to supply certain sensors. Combined with the quality problems we have seen from Teledyne and some of the performance and design issues, I can see nothing good in favour of Teledyne O2 sensors.

The AI PSR-11-33 range offer plug replacements for Teledyne R22-Ds, R22-2BUDs, Rebreather/06/01/07, R10s, R17s etc. We still have some work to do on checking the PSR-11-33s, but are fast tracking that and it is apparent already the quality is higher, price is lower, reliability better and performance more stable than any Teledyne product we have ever handled. As a result of very thorough testing and a recent further revelation on a business practice, we for one are not doing any further work with Teledyne sensors.

Cheers

Alex

SimonK

The USN has approved the AI cell as an alternative to Telydyne R10-DN used in the Mk 16 Mod

http://handle.dtic.mil/100.2/ADA443585

Simon

Mdemon

Worth using as a reference/4th cell to compare with the normal cells?

__________________
www.southwestmafia.com



"Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"

AD_ward9

Yes, though the user would have to remember the cells are slow so if it has been necessary to hit the eject button to the surface, not to rely on them. In all other events they work great.

Cheers,
Alex

dave t

thanks for the explanation Alex

A friend of mine used slow response cells in his inspo (I think they were German in origin) and nearly killed himself, Alex's warning on slow responding cells should be well listened to!!