I managed to pick up a discarded vacuum cleaner quite sometime back. It was a simple vacuum cleaner that had just a flat filter screen between the dust compartment and the motor. Looking at the construction of this vacuum cleaner, I reckoned that it would only be suitable for use if the dust to be sucked were quite large, like in a barber shop, where the “dust” were the hair that was lying on the floor. And since the dust compartment was rather small, the collected dust would have to be emptied quite often. And since there was no bag to collect the dust, the latter had to be emptied from the vacuum cleaner itself into an external dustbin or bag for disposal, possibly by digging around with a stick. No wonder the previous owner did not want it anymore. It was too difficult to maintain. When I found it, it was heavily choked.
But the motor and the vacuum fan was working alright, although the wire return spool spring mechanism was not working. I decided that it would make an excellent workshop tool for me if I could manage to improve on it.
This I did, by adding a cyclone and a container for it. I had to fabricate some supporting structures for them in order to work. My plan was to use it for dust extraction of my movable gantry cnc machine because some of the cutting jobs did generate a tremendous amount of wood dust.
The dust extractor would be fixed on a wall beside my cnc machine. Therefore I did not even need to have a spool to store the electric wires. The wires could be managed well by just hanging loose. The functions of the supporting structures were designed:
- To allow the assembly to be hung on the wall so that it could be removed easily.
- To secure the vacuum cleaner with motor to the assembly. Operation vibration will cause it to move away
- To secure a cyclone dust collector to the assembly so that it could be connected to the vacuum cleaner
- To be able to collect the dust in a removable container. This would eliminate the need to clean the filter/filter bag
- To be able to remove the container easily so that the dust can be emptied easily
The supporting structures were made of wood, plywood, steel rods, and springs. The connection hoses were cut from original. Some pvc pipes had their diameters enlarged by heat treatment or reduced by sandpaper so that they could fit the cyclone/vacuum cleaner.
Originally, the cyclone was just enclosed with a open top canister, pressed seal with the help of two spring loaded compression rods to maintain the vacuum. It did work, but because of the limited space available for dust collection, I decided to add another screw cap bottle at the bottom of the assembly so that I could have more space to collect the dust before I needed to empty it. Also it would become easier to remove by just unscrewing the bottle from its cap.
So I had to design a connection between the top canister and the bottom screw cap with its bottle. Since the wall thickness of the top canister was very thin, I fabricated a flange out of 11 mm plywood and glued a short length of PVC pipe vertically inside it so that the latter would poke through to the bottom screw cap.
Unfortunately, the PET bottle that I had available was not very strong, so I had to add in some other internal supporting frames to make it strong enough to withstand the vacuum pressure. I did this by gluing a cd with some spacer wedges so that the face of the bottle would be in contact with the wedges, all glued fast by epoxy resins. In another place, I placed some steel wires on the internal surfaces of the bottle and then glued them in place. Upon testing, they seemed to be able to withstand the vacuum pressure without collapsing.
The push-button switch for the vacuum cleaner was situated quite high up when the assembly was mounted on the wall. I used a few pieces of wooden strips to create a lever mechanism so that I could touch the switch from an accessible place.
Now, the vacuum cleaner does not choke up as I could very easily remove any dust collected by just unscrewing the bottom bottle.