Try dryer is opened now. It is full of wet beads. Also the spring is fully rusted

Check the condition in the photos taken. I try posting all before and after photos.

Please advice accordingly.

 

When I see the poor status of that corroded spring, I can't believe it can still perform its task.
Not sure there is a new one in the bagpipingandy set.

 

I believe the spring just keeps the desiccant beads compacted in the bed, so it will probably be OK once it is cleaned. The kit I purchased from Andy does not include a new spring or any other parts for the air dryer desiccant bed.

Cheers,

Don

 

The high-tech molecular sieve beads inside the dryer were wet. How do I treat these now? How do these be dried ? Should I simply keep them in sunlight to dry naturally?

Need some good home possible advice for this.

As additional info here, I want to mention that accidentally some of the beads fell off the container and separated from the wet lot, but within a plastic bag (no spillage). Those separated beads have dried completely and look like as good as new. Check the 2 photos

 

Technically, to fully dry and reactivate the molecular sieve beads requires heating them to between 400 and 600 degrees Fahrenheit for 15 hours, alternating between an argon or nitrogen atmosphere and high vacuum. Try doing that at home!

I think the best home method would be to spread the beads in a single layer in a shallow cake pan and bake them overnight at 500F overnight. That would probably go a long way toward drying and reactivating the beads.

CHeers,

Don

 

I edited my previous post and included the photos. Please advice.

Wondering how do I bake them in 500F at home :| will try it though.

 

If you have an oven, just turn it to its highest temperature (450F? 500F?). I would spread the beads in a thin layer on something like a shallow cake pan or a cookie sheet that has a rim around the edge. I'd leave the beads in the oven all night to dry them as thoroughly as possible.

 

Thanks. Will try doing it tonight and update soon.

 

As Don says, you can't dry the beads in a normal oven and air.
Baking them at 500 °F in an oven will just dry the surface.

Water is chemically adsorbed inside the chemical component of the bead and such chemical bonds are too strong to allow for substantial water release (i.e. from inside the beads) unless you follow the process indicated (high temp cycles under neutral gas) because of the rather large volume/surface ratio of the *****.

Actually, the beads always remain saturated in their volume.
Additional water becomes trapped in liquid form around them (kind of surface effect) in the dryer when wet air of the circuit passes through.
During air vents, liquid water is probably expelled but the water trapped inside the beads remains.
And if/when replacing the peblle bed with fresh beads, it would be chemically active only during a rather short period of time...

 

Sorry, did not understand the last statement.... does it mean that baking the existing beads to 500F are more effective than the new beads ?? or is it the otherwise ?

 

No, it's the otherwise, new beads are supposed to be non saturated (but they will remain as such for a short time only, when used).
Baking the existing beads at 500 °F will not unsaturate them, you would need to apply the procedure described by Don.

 

Hi paydase,

From the research I did when shopping for new molecular sieve beads, my understanding is that the size of the pores is specifically selected (3 Ǻngströms or 4 Ǻngströms) to adsorb (not absorb) water molecules on the surface of the beads, but to not allow water molecules to penetrate to the centers of the beads. To adsorb means "to gather on a surface in a condensed layer." My understanding is that this is not a chemical reaction but rather a matter of surface tension. I would welcome further education.

The benefit of adsorption is that by backflowing dried air from the air suspension system across the desiccant beads, some of this surface layer of condensed water will be evaporated, partially reactivating the beads. In practice I suppose some water may be absorbed into the center of the beads as you suggest.

I would think that heating the beads to a high temperature should cause most of the trapped water to boil out, leaving the beads mostly dry and mostly reactivated. If backflowing dry air from the air suspension will partially reactivate the beads, then IMHO baking the beads in an oven should dry them to a far greater degree.

BTW, the prescribed method of drying and reactivating the silica gel beads that were used in earlier air compressor dryers was to heat them in an oven at 275F for 90 minutes per quart of silica gel beads.

Cheers,

Don

 

Hope baking them at 500F for 6-7 hours will not burn the beads and make them brittle. For how long does this give life to the beads ? How often should this be repeated ?

 

Hi Don,

I agree with you clarifications, thx for correcting my wrong understanding and inaccurate wording used wrt adsorbtion/absorbtion.
Actually, from the reports here and there about the volume of water trapped in liquid form, ice forming under cold in the compressor and ineffective water "drying", I believed these beads were designed for absorption rather than adsorption.
But now that you make the point, it's true that it is probably a surface tension phenomenon catalysed by the chemical stucture of the surface.
That would explain how such a big amount of liquid water may be trapped and lead to ice formation under cold, hence why Jaguar uses a venting process through the beads to expel liquid water.
Your other information on the move from earlier beads (with probably a larger pores' size) seems to confirm Wabco's learning from experience, the adsoption process losing its effectiveness along time while absorption is more resilient to saturation and the pebble bed more prone to reactivation through violent air flow.
Also the use of the new beads indeed justifies some "reactivation" through standard heating in an oven. Good to know.
Thx!

 

These beads are silica and sintered ceramic based. What they don't like is thermal shock but they won't become more brittle. Put them in the oven from the beginning and wait until the end.
IMO no need to repeat the process.
For how long a life? Not long as discussed before, but still worth when the compressor is open

 

The molecular sieve beads are made of a ceramic material or clay mineral such as aluminosilicate that has a very high melting point, 1,920C, so there is no risk of making them any more brittle than they are in their natural state by baking them at 500F/260C.

Cheers,

Don

 

There was water dripping from the beads and the spring was totally corroded. I only baked at 250 for a few hours and it dried the beads.
My issue was a rear air spring that seemed to leak while driving. I parked it for three weeks and it did not sag. But finally got worse and the side would drop overnight.
The volume of air pumped is very small. Even a new compressor does not push much volume under pressure.

 

This is the best I could get. I feel the spring is too corroded to be cleaned. Not taking the risk of damaging it further. Any advice on this please ? I can do a spray paint at final stage.

 

When was this ? and what did you do about it ?

 

jagnew,

Spring steel is tempered to be pretty tough, so there's no real risk of damaging the spring unless you deform the coil somehow. I personally would not want all the corrosion to remain inside my compressor, and it looks like such thick crust that paint is unlikely to bond well to it.

Soak the spring in penetrating oil overnight, then scrub it well with a small wire brush, then degrease it with a solvent before spraying it with paint. If you have a die grinder or Dremel tool, that can speed up the cleaning process.

Cheers,

Don