Category: Dust extraction

Dust extraction – [Part 1]

In my workshop I have a lot of machines producing dust / chips. In order to not make the complete house / workshop dirty I connect a vacuum cleaner with cyclone to the machines. The downside of this is that every time I switch machine I also need to disconnect the dust collection hose and connect it to the different machine. To solve this inconvenience I decided to make a central dust extractor with fixed tube to all machines. Each machine will get a valve that can be opened or closed to get the suction to a machine.

For the valves I did some research , and I found that a lot of people use sliding gates for their dust valves. For example:


(Source: Reddevil on Schematheek.net)

I did not like the fact that these take up too much space. So I opted for a design that looks more like a ball valve. However a bit different, so I could 3D print it. I found some central door lock actuators for cars on my desk and thought of a concept to operate the valves with these.

A first test:

This was made for a 40mm pipe, the dimensions of the moving parts where not very good yet and it got stuck sometimes. After this test I decided to use 50mm pipe for the dust collection, the linkages etc I reused from the 40mm and it turned out to work very good. The only downside is that the valves only open to ±70%,. But for the small chips / dust that goes trough I do not expect any problems.

Valves assembly:

The next part of this project will be a current sensor unit.

Dust extraction – [Part 2]

In this part of the dust extraction build I will show the current sensor. This sensor measures the current that the tool draws and gives a signal to a central unit once it is higher than a set value. In order to leave the vacuum cleaner on during the machine spinning down a settable timer is added. Also I added a start stop circuit, witch can be used to manually start/stop the valve and vacuum.  This can be handy to clean the work table. These buttons are not placed on all sensor units.

 

This unit consists of 2 parts.

Part 1: the current sensor:

A current transformer (ASM-010) is placed around the live wire.

The output of this transformer is send trough a 50R resistance. This converts the output current of the clamp to a voltage. This voltage is then amplified and compared against a level set by the potmeter. After this a 555 timer is added to keep the suction active while the machines motor spins down.

Part 2: on / off buttons:

This part works with a set reset flipflop. This has 2 buttons connected to manually start / stop the dust extractor.

Total:

The output of the 2 parts are coupled together with 2 diodes to a transistor that pulls the interface line to the controller low when it wants to turn on the dust extractor.

 

The PCB I designed for this project:

In order to keep the potmeters in place I added a small 3d printed bracket.

Build in the enclosure:

The next part of this project will be the central unit.