Arduino/servos/blast gates project for stone mill installation (grain movement, bran movement, dust extraction)

Hi all,

called in at the weekend to find out if any members interested in the following project. Told quite possibly, so here goes.

I have a mill, a Moulin Astrie that is currently rented to a bakery in Berkshire but due to be installed in the Little Bread Pedlar bakery, Bermondsey Spa. Amongst other things this involves adding a mezzanine floor to the railway arch the bakery occupies from which to feed grain to mill and store grain, building a mill room around the mill to contain dust the mill is bound to give off. Space is very tight in the bakery creating numerous issues one of which is that it precludes lifting grain delivered in 1 tonne tote bag up to grain bin on mezzanine mechanically, via grain auger and/or bucket elevator. For this reason and others looking to complete a number of tasks pneumatically with negative air pressure i.e. suction and use of multiple cyclones both to collect material pre filter on vacuum power source and dump out different streams of material (grain, semolinas, bran, flour) where required.

I have two models, modern industrial mills which typically move things around pneumatically and deliver with cyclones and air lock rotary valves and carpentry shop dust extraction set ups that deliver suction to multiple locations selectively by use of a single suction power source and blast gates opening and closing going to cyclone on vacuum waste drum before dust extractor +air filters.

Essentially cannot dump out of cyclones into vacuum vessel(s), must create an air lock type effect to empty material but standard rotary valves for mills are both very expensive (+$4000) and much too big and clunky for our requirements and space (even DIY example). What I am looking at is creating an air lock chamber effect (similar to going for a space walk) by means of a pair of blast gates. I’ve got as far as a little manual test which so far favourable Next question - how to automate this? I hope this idea using Arduino/Servo Shield/Servos/blast gates to control a carpentry shop dust extraction setup gives a clue

any takers? Like to help? Expect to be able to put some funds in but don’t want to become permanent member (I think). Is there such a thing as a temporary member?

Andrew Forbes
Secretary Brockwell Bake Association

happy to consider the pneumatic piston driven blast gate solution already being investigated

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Hi Andrew - sounds like a great project - I’ve sent you a message.


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two comments on this.

  1. Be careful, flour is VERY explosive in dust form and can be ignited very easily. Google it to see just how powerful it is.
  2. Why use a vacuum ? use positive pressure and a contentious venturi ejector to lift the grain into the pipe and then transport it up to the first floor?


Hi Courty,

blowing highly undesirable way to move anything dusty around according to industrial milling consultant. How could one deliver to anywhere without blowing into atmosphere? One can hardly blow something into a sealed container.

Very conscious of flour and static risks, milling consultant advice is to included as much as possible grounded metal ducting but also there are carpentry workshop youtubes that cover grounding dust extraction set ups such as - I hope will be enough.


Hi all,

there was another idea that I looked at inspired by Japanese water hammers So when hopper material being delivered into is empty, vacuum + counterweight would keep a hatch at bottom sucked closed - until enough material out weighs the effect of vacuum and counterweight and it pops open.

I just found a commercial version of this idea

Nice in that no motor involved just weight and gravity. Main problem is that counterweight would have to be quite different for different materials being moved, for bran for instance, high volume low weight, might not work at all.

Fairly in depth discussion (by partisan author) of pneumatic v. mechanical movement of dry goods here