Inlet muffler/laminar flow element

ManCaveGear
Posts: 27
Joined: Fri Mar 27, 2020 11:41 am

Inlet muffler/laminar flow element

Post by ManCaveGear »

Hi everyone!
Here's my design of inlet muffler and laminar flow element assembly.
The idea is to allow air in through a low resistance filter placed in the filter chamber to clean air form thick flying debris (dust, mites etc) then direct it to a linear flow element.

Filter housing has a removable plug around which you can wrap a gauze, foam sheet or use a proper filter assigned to do this job. you then put it inside the housing.
Laminar element is a tube with two caps one is a 32mm connector (ventilaid side) with a mesh, and another with 34mm muff on a filter side also with a mesh. inside that tube you place as many regular plastic drink straws at 5mm dia. (not the thick ones) as you can, all cut to 100mm length to fit between caps. An screw it all in place with 3mm wood screws 5mm long, they can be a bit longer but within a reason.
All should be easily printable without supports in PlA



PLEASE LET ME KNOW IF THIS LINK WORKS!!!
Łukasz Hamanowicz
l.hamanowicz@gmail.com
Attachments
2020-03-27 (3).png
2020-03-27 (3).png (186.05 KiB) Viewed 1631 times
2020-03-27 (2).png
2020-03-27 (2).png (137.67 KiB) Viewed 1631 times
2020-03-27 (1).png
2020-03-27 (1).png (221.82 KiB) Viewed 1631 times
Last edited by ManCaveGear on Mon Mar 30, 2020 5:07 am, edited 2 times in total.

GrzesiekMy
Posts: 16
Joined: Fri Mar 27, 2020 7:09 am

Re: Inlet muffler/linear flow element

Post by GrzesiekMy »

Yes, the link works. Thank you! Is anyone able to print and test?

westwell
Posts: 3
Joined: Sat Mar 28, 2020 10:33 am

Re: Inlet muffler/linear flow element

Post by westwell »

Hi Łukasz

Just started a print of the 5 parts on 2 x Creality CR10 printers here in Scotland. They will be finished in 9 hours as long as no print failures (not expecting a failure as the parts look straightforward and I've added supports where I thought necessary).

What do I need to do to test them? If it would be any use, we could have a zoom session later and you could talk me through it.

Phil

ManCaveGear
Posts: 27
Joined: Fri Mar 27, 2020 11:41 am

Re: Inlet muffler/laminar flow element

Post by ManCaveGear »

first thing is fitting them together and suggestions on improvements i will have my set printed by then too so I will work on imperfections and welcome all the points on improvements of design, air tightness dimentions, fasteners (ie, screws clips etc.).
I'm sorry to say but I have already found some flaws in my design. Nevertheless I'm looking forward to your feedback.

The goal is to dampen ventilaid air inlet noise and create laminar air flow to decrease noise levels. The design is based on gun suppressors, compressor outlet suppressors, and the laminar element is just a design I know from the fluid mechanics classes at polytechnics.

westwell
Posts: 3
Joined: Sat Mar 28, 2020 10:33 am

Re: Inlet muffler/laminar flow element

Post by westwell »

Hi again, Hi Łukasz

Here are thoughts now that I've printed and assembled it. The prints came out fine and the overall design looks good. I'd be interested to see how it fits into the rest of the machine as I haven't looked at that yet.

Overall

a) I had trouble pushing the parts together. Normally when I'm modelling printed parts to push together, the male part is smaller than the female by 0.2mm all round. So for example, the plug filter end came out with a diameter of 35.7mm (radius 17.85) so I would be pushing that into a hole with radius 18.05 or diameter 36.1mm. On my printer the hole came out with a diameter of 35.7 to 35.8, depending on where I measured.

b) How airtight does this need to be, and how will we make it airtight? When I'm making airtight components I use a screw fit with a flange and a rubber O-ring, so they can be disassembled and reassembled. However, in the current climate, it may be easier to source wood screws than rubber o-rings. For your design, would we use sealing compound when pushing them together?

c) Continuing the previous comment, I wonder if there is a further general principle here that any replaceable parts (such as filters) must be easy to source. I like the way in this design that there is a lot of flexibility over what can be inserted in the filter.

d) I used supports for the muffler body, but I wish I hadn't (and I know you did say you thought supports would not be needed :) ) However, it did make me realise that a guiding principle over the whole project may be that, if possible, the parts are designed so that they can be printed without supports

Specific comments

d) For the muffler body, I thought that the support rods were much too weak. Several of mine broke while I was seeing if I could push the plug filter in. Do they need to be rods? Stronger might be if you did a "boolean difference" of a screw thread from a solid cylinder where the screw thread had 10mm gaps at 12, 3, 6, and 9 o'clock. I can draw a picture of what I mean if that isn't clear.

e) The plug filter seemed to be ok, with the exception that one of the vertical bars became separated from the bottom while I was twisting it. Could if be strengthened, say by having rib(s) on the inside of the bars?

ManCaveGear
Posts: 27
Joined: Fri Mar 27, 2020 11:41 am

Re: Inlet muffler/laminar flow element

Post by ManCaveGear »

Thank you very much for your kind comments and taking time and effort to print it.

I had same issues here too. I already changed screws to threads. I printed connectors only to make sure they fit together.
I allowed for 32mmx3mm orings or washers. If no washers are used sealant or some polymer glue will do the trick.

Also I'm redrawing it so that both units can be connected seperately to a 32mm PE tubing via a coupler that I'm drawing right now.

I will make changes on the plug and the filter housing too.
Bear with me It's a busy Sunday.
I will have mk2 ready this evening at maybe 10pm.

westwell
Posts: 3
Joined: Sat Mar 28, 2020 10:33 am

Re: Inlet muffler/laminar flow element

Post by westwell »

Sorry for the delay, had a couple of print failures. I have it now, though

Thanks for this model. It is a really good upgrade to the previous one. The two caps screw nicely onto the middle now, that was a good design, I think
Also the coupler screws on fine.

The filter is definitely stronger and I think that will help.

Two questions:
a) how does the filter stay in the muffler? Are we relying on it being a tight push fit, or would you consider screwing that in, too.
b) should I test this arrangement for airtightness? I don't know how airtight this needs to be, but from my work with bagpipes, I've found out that there can be slight leaks between layers (in my case I've tended to use 100% infill to reduce the risk of slight air leaks between layers)

ManCaveGear
Posts: 27
Joined: Fri Mar 27, 2020 11:41 am

Re: Inlet muffler/laminar flow element

Post by ManCaveGear »

Hey man! How are you?
Instead of using full infill I use thicker walls - 5 lines. Also I print with 0.5 nozzle and 0.32mm layers. For parts that require smoother surfaces I use 0.16mm. Better material flow due to bigger nozzle gives me great layer adhesion.
As for air tightness, shouldn't be a problem. Pressure we are dealing with here is not so high/ low so should be alright.
I did not design anything for the plug, although I planned a snap in. Thread would be a bit dodgy with random filter like sheet material (foam/HEPA). What about gaskets did you try to find use anything local?

Ps. Post some snaps of your print!

Post Reply