FredR

Alan,

I understand how the separator works but what is not clear is why oil is getting carried over into/accumulating in the gas outlet chamber. Maybe I am missing something here but I just cannot visualise oil being able to accumulate in the bottom of the pro vent such that it carries over into the outlet chamber.

My assumption in Jakes case is that oil is accumulating in the bottom of the gas outlet chamber so having some weep holes for oil to drain back should not cause any issues- especially if there is a small hydraulic seal caused by oil ponding.

On a spearate [minor] note I also see the word "filter" being used. I would describe a filter as something that removes particulate matter from either an oil or a gas stream. Perhaps it is better described as a coalescing screen enabling suspended droplets to coalesce into particles bigger enough to drop out on the screen face.

My next trial is to remove the wire mesh from the baffle in my filer neck and see ho wth epro vent copes with that. Indeed I am thinking whether to rty removing the baffle altogether and see how [if?] the Pro Vent copes with that.

Regards

Fred

Alan

The only way to the drain is THROUGH the element (call it whatever) there is NO OTHER WAY - just look at it... there is no flow any other way unless you drill it. The oil has to go to the gas outlet outer chamber & then drain down.

So it most likely is not coming up - just going down...

You need to just look at it - then its obvious...

Alan

FredR

Alan,

The mix enters the top tangential chamber, free oil is knocked out on the outer walls and flows co-current with the gas stream into the central section. The free oil drains directly to the oil outlet at the bottom of the central chamber and the gas then passes through the screen into the gas outlet chamber. As the remaining gas/oil tries to pass through the screen, the remaining oil droplets are knocked out on the inner chamber side of the screen and drop into the bottom of the central chamber where they exit. Trust we both agree that is how it works.

What puzzles me is why Jake was seeing oil in the gas outlet chamber suggesting the screen had failed to knock the oil out for whatever reason.

Regards

Fred

ptuomov

How is it going to drain thru this (unless there are holes?)



I can see an alternative system in which the filter element has a hole in the bottom and seals on the sides. But Mann-Hummel ProVent 200 has a sealed filter element bottom and the oil and air outlets aren't sealed after the filter. At least that's how I recall it, I don't have one in hand now.

FredR

Apologies- Just took a closer look at mine and indeed my understanding was incorrect. I was under the impression there was a drain path in the base of the centre section but seemingly not the case. One must conclude as Alan stated that the oil is expected to pass through the element but that seems real strange to me.

it would be interesting to know what is going on pressure drop wise across the unit when at full flow.

Regards

Fred

Alan

Exactly - Fred - stop trying to remember how it looks... and just look at one!

Alan

Alan

Oh you did! good.

You will note the o-ring seal at the top ring above the outlet - but there is no o-ring on the bottom end - it really doesn't even touch the walls at the bottom.

Alan

ptuomov

I believe that coalescing filter works most efficiently if you can let both oil and air pass from the same side. It's a lot harder to create a coalescing filter that leaves the oil on the entry side.

I agree that measuring the pressure drop at different flow rates would be really interesting, both with filter dry and filter wet with oil.

Tim968

The Provent 200 will not separate all of the oil mist, and leave "oil-dry" crankcase vapors at the outlet. Here's the extract from their literature, claiming only 85% separation efficiency for the typical coalescing element. What that means to me is that I will still carry some oil mist droplets in the outlet vapor line, and in fact that's what happens in my ROW '92 GTS. I suspect that when I operate at higher speeds I simply can't coalesce the total oil vapor coming out of my engine.

We might want to keep in mind that the Volkswagen TDI crowd really like the Provent because it also nicely filters out the tiny soot particles that characterize diesel crankcase oil. These soot particles get laid down in intake manifolds, after coolers, etc, and form a black grunge that has to be periodically cleaned out. Trapping all that crud out via the Provent helps the situation for those guys, and they aren't sweaty about oil consumption in the first place - it's about choked-up-with-grunge intake manifolds and dirty turbo-compressor wheels.

The ultra-efficiency Provent 200 filter effectively doubles the pressure drop through the Provent, up to 20-35 millibar -which is about 0.3 to 0.5 psi differential across the element. Even with the ultraefficient Provent 200 coalescing element, the claimed separation efficiency is still only 85 to 90%. The Provent literature infers that their coalescing elements will separate droplets down to 0.8 µm (and makes some reference to Sauter mean diameter). An ultra-efficient higher separation efficiency infers higher pressure drop through a smaller media pore throat, or more tortuous passageway, along the length of which the oil droplet will find its way to another droplet and eventually coalesce into a big enough droplet to fall away.

All that science makes me think that the 10W-50 puddle in my GTS intake will only be half as big as it is now, which is still too big.

I asked about the ultra-efficient coalescing element in late November 2013 and got this e-mail reply;

Mann #LC 5002 x is a special order item which has a 6-8 week lead time & is $61.96 each.
Mann #LC 5001 x is in stock & is $49.19 each.

Both filters fit your Prevent. (see attached, page 8)

Thank You,

Frank Mull
Application Associates
252 Lackland Dr.
PO Box 488 Middlesex, NJ 08846
Office: 732-627-9400 Cell 732-627-9319 Fax: 732-627-9401
frank@applicationassociates.com

"Your complete satisfaction with our products and service are our primary goal!!"

Colin is on the right track, arranging the air-oil separator downstream of a properly designed evacuation pump. The differential pressure to flow through the air-oil separator is afforded by the pump itself, not by

a) Corresponding pressure rise inside the crankcase to push through the coalescing media, or

b) Applying differential pressure through a PCV valve drawing on the discharge side of the Provent 200 (which was my unfortunate experiment)

If a person has adequate differential pressure available, then they can change from a very thin and light coalescing element (as employed on the Provent) and move up to a coalescing element with more depth. In bygone years, large industrial air compressors using oil flooded intermeshed helical screws had in-depth lambswool coalescing elements, which extracted the oil mist passing through the screws, and drained it back down into the oil sump for reinjection back into the screws. When these caught fire due to overheating, the smell was pretty bad, as you can imagine.