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Dust Extractor

A 3D printed cyclonic dust extraction attachment for a domestic vacuum cleaner.

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A printed dust extractor attachment for an upright vacuum cleaner. Being sick of killing my vacuum cleaners because of the, literally, stupid dust extraction methods they use I decided to design and build my own.

Restricted to the printers build platform size I went about researching how cyclonic dust extractors worked. Realizing that there is essentially only one method to extract particulates from air without a mechanical filter it was a matter of optimising this is a system. Seeing how the branded cyclonic vacuum cleaners work I thought that they weren't really the best solution for the printed construction method.


Cyclonic dust extraction methods aren't new and are common in industrial settings. The principle is that a vortex is created with rotating air. In the middle of that rotation is low pressure and the more energy that the vortex has the greater the difference in pressure, eg lower. So using the low pressure region and the centrifugal of the rotation a complementary mechanism exists for the particulate extraction process. Air at the centre of the rotation has the lowest pressure and only the most buoyant substance can sit there which is only the cleanest of air. Extracting this air with a vacuum pump is essentially do the most natural thing for a cleaning process.

Typically industrial dust extractors use a single vortex that removes the large particulates that cause dust. The commercial domestic vacuums require more finer particulate to be removed and use very small vortices to do this. Without going to this extreme this project created a 7 vortex system with and external bent vortex that induces the rotational air structure.

This image shows the inner 7 vortex generator that the inlet air structure rotates about. Large particulates are removed here as the air accelerates over the curved surface and into the inner 7 vortex generator. The slow moving 'high' pressure air that contains the particulates from the small vortices exits below the accelerated feed air and should mix with the large material and fall to the bottom.

  • Funnel Replacement & Observations

    Nelson Phillips7 days ago 0 comments

    It seems that the funnel outlet was not strong enough and broke under very little use. This was beefed up and in the process had the internal material removed, which make more sense for a number of reasons. There was a constriction made through poor design and the material was reduced significantly.

    Some observations from the use, about one hour, is the amount of dirt on the outlet of the cyclonic separation section. Knowing that this system will not remove all the dirt particulate from the air it still seems like a lot. There seems to be a small amount of fluff catching on the inherent print imperfections that might be seen in the images below. However, it also might mean that a Hepa filter that all systems like this run is clearly needed. 

  • Iteration II

    Nelson Phillips12/03/2017 at 06:21 0 comments

    The second iteration of the cyclone dust extractor takes the first iteration and improves upon that. This seems to have been successful and the 40 hours that this took to print was not a waste of time.

    Mounting the extractor.

    Using the same mounting points as the first attempt. A printed bracket was versioned to fit and then attach to the extractor by drilling four 3mm holes piloted by the bracket. The bracket was then bolted to the extractors chamber fine element chambers screwed on sealing the chamber and extractor mechanism. No gaskets or silicone seals used at this time.

    Initial Assessment

    Apparent success! The above images were taken after the first short run of this extractor. They show most of the debris in the main chamber and the small chambers, difficult to see, holding a small amount of fine dust.

    Initially when the extractor and the original chamber was taken off the vacuums chassis there did not appear to have any additional detritus around the filter. This was unlike the first iteration were it was obvious that material had made it through the extractor. So this was a good sign. Continued dismantling of the debris accumulating chambers revealed that most of the material was contained within the first chamber.   

    Possible problem/s

    The size of the plumbing is smaller than is desirable due the restricted volumes that is being worked with. This may be making the motor work a little harder than preffered, however putting is a fresh clean filter may address this. An old dirty filter would put more strain of the motor than small diameter hoses and this should not require changing for a long time.

    Analysis

    A quick calculation of the costs and possible benefits.

    The vacuum itself was about $280AU and subsequent replacement filters $23AU, postage about $10AU.

    The filters are supposed to be replaced every 6 months. So over a 4 year period that is $92 + $10 for postage. 

    The major reason this device was made was because the filter needed cleaning every time the vacuum was used. This took about 10mins and if vacuuming once a week over a year that is 8.7 hours @ $22/hr, calculated on housekeepers wage, that's $190 for a year. Now it takes a minimal time and is way less shit.

    On the assumption that the vacuum runs more efficiently and extend the life of the vacuum by 50% the total value of the extractor is,

    140 + 1.5(102 + 190 ) = $578 over a 6 year period. 

  • CAD Design Ver 2.

    Nelson Phillips11/20/2017 at 11:16 0 comments

    Addressing the issues from the previous version.

    • Separating of the of the debris collection and flow structures need to be more pronounced. 
    • Assembly need to be easier.
    • Simpler design with lower part number without the need of solvent welding.
    • Redesign for printing.
    • Debris collection is easily accessible. 
    • Hoses need to be attached easier. (todo)

    Separating the inlet stage and the cyclone stage the external shell forms the main chassis able to collect the larger particulates and hair, hair was a real problem. This also has been altered to make the assembly easier with all seven dust collectors serving the dual purpose of mechanical seal.

    Assembly will be by screwing the collectors onto the base.

    more

    ok

    The CAD will be released if the design works.

  • Version 1. Review

    Nelson Phillips11/19/2017 at 04:29 0 comments

    After running and trying the vacuum under different condition I developed an understanding of how this device does and doesn't work. Initially this device did seem to work to some extent, but this did not last long and alterations were make to address the issues. These alterations did not work at all and made the device not functional. However, it gave an insight into how such a cyclone vacuum system works.

    Outlining the issues and why they are important to function.

    The purpose of this project is to remove the fine particulate from the air before it gets to the supplied filter. Initially this was successful and the only debris that accumulated around the filter were the larger and lighter, eg. plant material. So the this gave the first result about the fluid flow structures and the causes of these structures.

    The basic illustration of the flow structures above forms the input and initial sorting mechanism. Here is where the main area of the design impacts how effective the sorting mechanism is. As the flow rotates about the centre the debris is forced against the exterior. However, inherent in 3D printing the surface is not smooth stalling the debris and reducing the force against the wall. My thinking is that this explains why the larger and lighter plant material does not deposits into the bottom of the system. This in turn clogs up the rest of the system slowly deteriorating its effectiveness. The image below attempts to illustrate the physics of the boundary conditions with forces.

    To counter the clogging of the of the system a grate was placed across the entry of the main cyclone mechanism. This caused more problems than it solve. Air was then pulled into the cyclone exist therefore destroying the mechanisms function. This super poor decision at least reinforce the need and reasons for a redesign of the inlet and cyclone mechanism. 

    Improvements for Second version.

    • Separating of the of the debris collection and flow structures need to be more pronounced. 
    • Assembly need to be easier.
    • Simpler design with lower part number without the need of solvent welding.
    • Redesign for printing.
    • Debris collection is easily accessible. 
    • Hoses need to be attached easier.

  • The build.

    Nelson Phillips04/25/2017 at 08:00 0 comments

    Without going into to many details about how I came to the dimensions because to logic was crude and was mostly governed by the size of the vac and flex hose available.

    This give a rough guide as to size of the body, the hose was limited as the common flex vacuum hose was just a bit to big. Searching I came across so 22mm outdoor water hose, not ideal but it would work in the constraints of the vacuums camber. The image below shows the original idea of a bracket interfacing with the chamber inlet, but it also shows the space constraint.

    The hose needs to sit there then turn and exit just where that dark circle is drawn because the filter that i was always planning to keep took the remaining volume. However, it turned out that the hose would fit inside the inlet perfectly creating a stable seat.

    No going back from here the holes where drilled and filled, and the hose inserted.

    Going back a few steps because I printed the extractor first, but these images illustrated some early design decisions as to how the space inside the chamber was a major influence. For example on of the original idea was to have the extractor contained within the chamber. The tightness of space and lack of ability to model parts exactly to the shape and dimensions of the chamber ruled this out.

    The filter and the chamber that it came from.

    Design and CAD

    Knowing that the dust extractor is a common and relative old technology the design started from gaining knowledge of how this technology actually worked. Standard dimensions were easy to find and simulations consolidated some thinking about the lower portion of the cyclone.

    The principles set the cyclone throwing the dust to the sides and it then falls below the cyclone to the chambers floor. But, having a single cyclone would require a larger chamber and from principles it would not have a high velocity air speed. So splitting the flow into originally 4 then 5 cyclones would substantially increase the angular velocity.

    Printing the flow generator also provided design constraints but also opportunities with an organic structure separating the incoming air and the high velocity cyclones. From here however it is not clear if this provides a solution but this is what I printed. So fingers crossed.

    bottom half

    top half

    and together

    All the parts printed.

    The upper and lower cyclone generator solvent welded together.

    A threaded attachment was printed separately and stuck to the chambers inlet with the help of silicone.

    similarly the outlet

    Inlet to the vacuums chamber.

    And the final result with brackets printed, solvent welded, drilled and screwed.

    It does work.......

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caution9 wrote 3 days ago point

Fantastic Project.  I've been wanting to do something similar for a long time.  I'm tired of cleaning and washing the filters in my vacuum every two or three sessions.    I've tried minor modifications like adding a thein baffle and changing the air flow in the upper chamber of my vacuum.  Neither has proven beneficial.   

If I had access to a 3d printer I would be printing your cyclone now.

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