Air filter pointless? Exhaust & air filter combo?

I was kind of wondering if it may just end up being a custom periscope style vent pipe to route the exhaust from the Glowforge’s existing vent hole down and into the back of the filter. I am very curious, as in my case, I don’t have a remotely convenient way to vent outdoors, so will be largely dependent on the filter as long as I am in my current (rented) house, and would like to know whether I need to plan for additional rear clearance even without external venting.

Not sure I understand your question? You do need a bit of rear clearance to couple the Glowforge to the air filter.

I think what we didn’t know was whether the GF main unit somehow vents out the bottom into the filter unit or whether the exhaust still comes out the back and is then directed into the filter. I still hesitate to say that we now understand. Your answer implies that the exhaust port(s) on the back are used (maybe with the dryer hose?) but previous replies made it seem as if some automatic redirecting of the air occurred. Clarify?

I had a mental image prior to this which was (now that I think about it) impossible. I imagined the air drawn straight down into the filter which rests under the glowforge.

But, since you can freely remove the filter, and the glowforge is relatively air tight without the filter on… there cannot be holes under the forge to send air straight to the filter.

The only way it can possibly connect is by having a small adapter/connector which attaches to the normal dryer-vent connection, does a quick double-90 degree flip around, and then has everything in to the filter.

The down side of this is… the wear on the filter will be uneven. Most of the contamination should wind up depositing right at the entrance to the filter, rather than being semi-evently spread out.

Hopefully my image of the outlet from the filter being distributed all around is ALSO in error. Having a single outlet on the far opposite end of the filter would mean you can have quite a few layers through which the air passes. This would mean you can gradually reduce the filter size, and help prevent clogging for a fair bit longer than otherwise. As well as remove a TON of the smell/particulates.

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I don’t know, but if I were designing it there would be a molded-in manifold structure to distribute the emission from the forge across the entire filter face.
What I do know, is Dan has better engineers than I. :pray:

There is going to be a degree of uneven distribution just by proximity, and that area of the filter is going to face load first, but that’s ok. The rest of the area will still be effective.

Yeah, my mental image has morphed a bit too. I was really happy to hear Dan confirm they are still on schedule. You know there have been a myriad of details that went sideways, and the contingency time he built into his projections absorbed them.:thumbsup:

Nothing like reading a man’s book to get into his mind. Judging from the product of their union, the founders have a handle on it. I would be surprised if a major feature like the filter was found wanting.

Sorry for any confusion - there’s a coupler as @jacobturner describes that takes the air out of the GF and into the filter.

Particulate distribution across the media’s always a challenge. Fortunately we’ve got an outstanding engineer on it. We’re not just plopping a vacuum filter and a sack of charcoal briquettes in there. :wink:

@rpegg, if I said anything to the contrary that you happen to recall, please do let me know and I’ll see about correcting or clarifying.

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No, it was just us making an assumption. In answer to a question about switching between using the filter and venting you responded…

We thought that the part about “If you use the filter, you can’t vent”, meant that you would need to physically remove the whole filter unit to place the vent out the window. It sounds, again assuming, that you just need to remove the coupler and then mount the dryer vent out the window.

There has been discussion of venting filtered air out the window, so as to minimize objectionable fumes reaching nearby neighbors. Now that we understand that the filter is coupled to the Forge via a duct, couldn’t the filter be mounted in a window and connected to the Forge by a longer duct? This assumes the exhaust from the filter comes out one side…

“which exhausts through many openings into the surrounding room”

Probably not on one side.

Then perhaps if exhaust comes from all but one side, a partition could be built to include that one side, with all the other sides outside the partition and venting to the outdoors?

This shouldn’t be a problem if they use a diffuser at the filter to disrupt the inward airflow and slow it down by spinning it into vortexes and thus spreading it out. The drawback of diffusers is that by sitting in the way of the airflow, they tend to collect larger debris.

You still have to account for pushing the airflow all the way through the duct tubing. It may be empty space and everything may be tightly sealed, but all that air in the ducting provides resistance that the single lone GF fan shouldn’t push alone by itself.

My understanding is that the filter has its own fans, so the task of moving air between the Forge and the filter is shared by the two devices. Regardless, if the longer duct proved to be too much resistance, an inline booster could be added. I’m just suggesting that if someone wants to go to the trouble of venting cleaner exhaust, it should be do-able with this arrangement. The earlier idea of building a shroud around the filter and venting the effluent out a window would be more difficult to accomplish.

Another point to consider is that the two 90 degree bends in the coupler translate to many feet-equivalent of straight duct. If the connection between the Forge and the window mounted filter could be accomplished by a relatively straight run of duct, it might actually cause less resistance!

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You may still need the shroud if the filter doesn’t have a top cover. Which would be reasonable since it is meant to sit under the glowforge, so a top cover would be pointless.

If that is the case, I would imagine that adding a flat panel to cover the open side of the filter should be pretty easy to do.

I totally agree, 90-degree turns are the Devil’s work and pretty much the equivalent of air hitting the side of a building/wall. The fact that it’s expected to do a complete 180-degree turn to go back into the filter sitting underneath is going to add noise, I think, as well as everything else. An as-straight-as-possible route is definitely the way to go.

I guess I wasn’t clear from your pen drawing if the center-window duct egress was intended to be fan-assisted or not. I assumed not, my bad.

By the back and forth on this thread it is clear we still have no where near enough info to do anything more than speculate as to the design of the filter or the GF filter interface. Also keep in mind there is likely some sort of common control. If I remember correctly the fans on the filter and cutter are controlled through the cloud,. That might mean an electrical control between the units. Until we touch a filter or see a demo everything is still guesswork.

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Very good point. I forgot about the electrical connection!

Correct.

No, because…

also…

I’m not going to tell you it’s impossible, just that it’s nontrivial. Very nontrivial.

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So probably some sort of custom electrical interconnect that would be hard to extend to a window?

I am pretty sure it was said that the air leaves the filter out of many openings in the bottom. Mounting the whole thing in a window like @fan-of-glowforge mentioned is an intriguing idea, but you would need a pretty big window to mount it into. The filter dimensions are larger than an entire average 1970s era basement window, for example (based on my examination of said windows in my basement :-))
My thought is that it might be easier to place the Glowforge/filter combo onto a custom-built vacuum table that would suck the majority of the filtered air down and then out of the room through a pipe. Even if it got only most of it, that would still go a long way towards ensuring the canaries live another day when you want to raster a detailed photograph onto a 12x20 sheet of something that releases Formaldehyde.

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