Breather tube moisture trap

[zoidberg]

I noted a reference in 'Practical Sailor' mag to inline devices which extract water/vapour from the air passing through the tank breather tube. Silica gel is used and beneficial claims made.
Can anyone point to a similar product available in UK/Europe?

 

[Sandy]

For winter storage I use some insulating tape over the breather.

I have seen something in the past that fits your description, but discounted it as a gimmick.

 

[NormanS]

For winter storage I use some insulating tape over the breather.

I have seen something in the past that fits your description, but discounted it as a gimmick.

Can you explain your logic? If you feel that there's enough air flow in and out to make it worth while taping over the breather, presumably because of temperature fluctuations, do you think that putting tape on will prevent the expansion and contraction?

 

[Sandy]

Can you explain your logic? If you feel that there's enough air flow in and out to make it worth while taping over the breather, presumably because of temperature fluctuations, do you think that putting tape on will prevent the expansion and contraction?

It stops rain, hornets (a problem specific to the closeness of a nest to my boat) and dust getting in.

Sorry. Irony, see paragraph 2, does not work on an internet forum. Next time @zoidberg and I are on the river we can meet on either the English (his club) or Cornish (my club) side and mull the pros and cons of fuel tanks breathing.

 

[thinwater]

Taping a bag over the vent will certainly eliminate winter moisture. The tank will breath, but it will be the same air, over and over, no problem.

I've had two, one made from a Vetus filter that I modified, and the other as below. The gel is simple enough to get on Amazon. The most important thing is to locate it such that neither water nor fuel can contact the gel (a high loop).

The H2OUT design can be very easily be duplicated for a few dollars. Hardly worth ordering, since the local hardware should have everything but the gel.

• Tube what ever size you like. For diesel, either aluminum or PVC conduit will work. Either 2 inch or 3 inch, depending on tank size. The only advantage of clear is visibility. But this is something you don't need to check for years. Just automatically regen at 3 years. Or 5 years.
• The end fittings are what we call plumbing no-hubs in the US, or Fernco caps, after the largest US manufacturer. They are neoprene.
• Create the end fittings from washers, threaded barbed fittings, and conduit nuts. Self explanatory, I hope. That is how the H2OUT ones are made.
• 2 hose clamps.

The gel lasts 3-5 years, after which you can regenerate it on an outdoor stovetop (leave it in the open until the gel changes completely, which will displace any hydrocarbons, and then cook it on low until it changes back).

[Probably not important if you use your boat, but I am a chemical engineer, have worked with vent driers a lot, and this is how it has be done successfully on a boat.]

 

[tico]

We use such a thing when converting forklifts for use in cold stores. It prevents moisture being drawn into the oil tank.
Will try to get the details tomorrow

 

[RunAgroundHard]

Google "breather vents".

Immersion Proof Breathers Archives

 

[zoidberg]

Next time @zoidberg and I are on the river we can meet on either the English (his club) or Cornish (my club) side and mull the pros and cons of fuel tanks breathing.

Sounds like an invitation to sample a few jars....

 

[Sandy]

Sounds like an invitation to sample a few jars....

Always an open invitation.

 

[tico]

Update...
Those nice people at MP Filtri in Evesham supply a 'dessicant breather' Ref: SAW115
Phone number 01386 258500

 

[William_H]

The question is will it make any significant difference to the amount of water getting into fuel. If it averts water in fuel from air vapour then why does every one not use such a simple device? Boats aircraft and vehicles would all benefit if it helps. ol'will

 

[thinwater]

The question is will it make any significant difference to the amount of water getting into fuel. If it averts water in fuel from air vapour then why does every one not use such a simple device? Boats aircraft and vehicles would all benefit if it helps. ol'will

a. Vehicle (gasoline) fuel systems are sealed.
b. Cars are not laid up for the winter.
c. They turn over the fuel more often than the typical sailor who would take years to go through a tank.

No, it won't make a difference if you run the motor regularly. That said, e10 absorbs water from the air pretty quickly, diesel only by condensation of dew and fog inside the tank. A good high loop and smart vent location help a lot. And nearly all water in tanks comes past the filler o-ring.

 

[PabloPicasso]

a. Vehicle (gasoline) fuel systems are sealed.
b. Cars are not laid up for the winter.
c. They turn over the fuel more often than the typical sailor who would take years to go through a tank.

No, it won't make a difference if you run the motor regularly. That said, e10 absorbs water from the air pretty quickly, diesel only by condensation of dew and fog inside the tank. A good high loop and smart vent location help a lot. And nearly all water in tanks comes past the filler o-ring.

Yes indeed folks. Change the O rings as a service item.

We can now have a long debate about the lifespan and service interval of fuel fuller cap O rings

 

[penberth3]

For winter storage I use some insulating tape over the breather.

I have seen something in the past that fits your description, but discounted it as a gimmick.

Agreed, a gimmick and a waste of money. The silica gel will soon become saturated then the device will have no effect. It would need regular removal for drying out.

 

[zoidberg]

Agreed, a gimmick and a waste of money. The silica gel will soon become saturated then the device will have no effect. It would need regular removal for drying out.

The test article on 'Practical Sailor' suggested otherwise. That's why I thought to raise the question here.

There's a difference in credibility between a carefully-conducted 'longitudinal' test programme, and an opinion based on nothing very much. I'd hoped to hear from some folk who'd actually used such a device, and what they experienced.

 

[RunAgroundHard]

Not all vent filters are desiccant. I use the non desiccant type extensively in my industry: purged electrical junction boxes vents - when the item is switched off and the purge air stops, there is a risk of moist air entering the junction box, the matrix vent style stops that; breather caps on hydraulic circuits at tank tops and on anti syphon tubes that prevent moist air being drawn into the hydraulic circuit or tank; control air for pneumatic systems and bulk powder pneumatic transfer. They are not fit and forget but to be honest they last a long time and a brief external inspection will show if they are blocking or not.

This is an article from Marine How To that measured if most air would enter a diesel tank, condense and accumulate Does an Empty Marine Fuel Tank Condensate? - Marine How To

His test and conclusion, plus his experience working on boats, suggests that there is no risk of condensation. Therefore, for a typical diesel engined sailing yacht, there is no need for this reason. If you get knocked down and place the vent underwater, the diesel will likely remain on top in the vent line and prohibit water coming in anyway. Apart from a filler cap leaking, I am struggling to think why a vent would be fitted with anything to stop moisture from entering. Bugs are such a low probability and even less so as a hazard to diesel if they do get into your tank, then this appears to fit into the pointless expense and effort space.

 

[thinwater]

The test article on 'Practical Sailor' suggested otherwise. That's why I thought to raise the question here.

There's a difference in credibility between a carefully-conducted 'longitudinal' test programme, and an opinion based on nothing very much. I'd hoped to hear from some folk who'd actually used such a device, and what they experienced.

Life expectancy between recharge ranged from 3-5 years, depending on location (Chesapeake vs. Seattle WA), tank size, and fuel type (e-10 and diesel). Four test boats. Not as much range as you would expect.

One of the reasons they last longer than you would think is that the fuel vapors push some of the water back out. In the case of e10, the alcohol does this quite aggressively, reaching an equilibrium.

Recharge consists of slowly heating the resin in a pan on the sternrail grill for 20 minutes. Before doing this, leave the resin out to fully change color--this forces the hydrocarbons out, preventing fire hazards and reducing odor during heating.

In the case of e10 the reduction in fuel evaporation more than paid for the device alone.

---

Worth it? I'm not going to die on the mountain. There's lots of OCD maintenance around boats and this falls somewhere on that continuum. For gas motors with installed tanks using e10, you would be silly not to use a vent filter unless you run all winter.

Gimmick? These are pretty common in industry.

 

[Sandy]

I wonder if anybody has done some actual research? Some very rough calculations.

I have a 100 ltr tank or 0.10 of a cubic metre.

According to gegcalculators.com a cubic metre of air with a temperature of 15°C at 85% humidity holds 6.05 grams of water.

In total my empty tank could hold 0.605 grams. At 90% full is c0.55 grams.

I am sure somebody can come up the the weight of water in a raindrop.

 

[Fr J Hackett]

If you leave silica gel or any other desiccant exposed to UK autumnal / winter atmosphere it will rapidly become saturated and ineffective, a waste of time of course you could regenerate the silica gel in an oven once you know how long it takes to be deactivated, it won't be long.
Better as Sandy says just seal the vent and reduce the airspace as much as possible.

 

[Fr J Hackett]

I wonder if anybody has done some actual research? Some very rough calculations.

I have a 100 ltr tank or 0.10 of a cubic metre.

According to gegcalculators.com a cubic metre of air with a temperature of 15°C at 85% humidity holds 6.05 grams of water.

In total my empty tank could hold 0.605 grams. At 90% full is c0.55 grams.

I am sure somebody can come up the the weight of water in a raindrop.

The problem will be the condensation cycle which takes water out of the atmosphere and deposits it on a cold surface ie the tank sides and top, in a continual process.