Dear All,

I'm in maintenance dept, one of our ship, has several pneumatic valves installed to the actuators, which control the butter fly into open/ close position. These are valves are controlled remotely. the problem is we are at much time in the sea. So, because of the sea environment - that is humidity & salt content makes these valves failing.

More info (pls check details about valve):
http://www.metalwork.it/eng/img/prodotti/valvole/21GB09 Namur.pdf

Please let me know the best way of maintaining them .

Also, I would provide any more info if you guys. Lastly, thanks for the future support.

 

In your investigation of the failure, where does the problem reside?

Is the high vibration environment causing the air solenoid to fail?

Do you have high humidity and/or salt in the air lines contributing to failure of the air solenoid?

I see nothing in the literature about these valves being suitable for a marine environment. What has the manufacturer told you in regards to the use of these valves for shipboard use?

Are these the only pneumatic valves on the ship that are causing problems?

Are you air compressors functioning properly?

Can you provide more detail?

 

IP65 is completely unsuited to shipboard service, given that you are experiencing maintenance problems. You also need to check the actuator rating as well.

you need a minimum of IP66 or possibly IP67 enclosure ratings and depending on the degree of immersion risk pehaps even a higher rating.

 

You could start by telling us more specifically how they fail - electrically (e.g. coil failure, wiring), mechanically (e.g. stuck), corrosion (e.g. coil, mechanical parts, type - internal, external, etc) , etc.). Be as specific as you can.

You imply that a corrosion mechanism is present (e.g. humidity & salt), so the first step would be to replace them with valves constructed out corrosion resistant materials (always better to prevent rather than maintain after the fact). If you do not have clean air, pneumatic components will fail. Vibrations have also been known to cause failure of solenoid valves.
We would have to know what the failure mode is to see if there is any preventative maintenance other than periodic inspection and testing or periodic replacement that would help.

William (Bill) L. Mostia, Jr. PE
ISA Fellow, SIS-TECH Fellow,
FS Eng. (TUV Rheinland)
SIS-TECH Solutions, LP

Any information is provided on Caveat Emptor basis.

 

Dear Thomson,

Thanks for the input, I was not able to check as we were having the inspection working going yesterday.

 

Dear D,

Thanks for the info, I will find out the rating on the actuator,And mostly these are valves & actuators are not immersed in water but randomly they are washed with water, when the ship crew is cleaning the ship.

 

Firstly, I would like to thank you for your post which has given me some very good info.

There are many failures but the mechanical failure is the worst. The pneumatic valve gets stuck and will not operate remotely, you will to change the pneumatic valve and repair the remove valve.

There is also less failures of electrical, ie , coil gets damaged and also sometimes, there are analog i/o cards that get damaged too.

As preventive maintenance on these valves, we lubricate the air ports of the pneumatic valve with oil, before start of any job. And incase if there is not job to be done in 2 days, we apply soft grease to the air ports.

The air is not clean because we are lubricating these valves and the oil gets in the airline.

Please let me know, if you would any more info.

Thanks
Syed Misba