<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: [pianotech] Metro Vac 'n Blo</title></head><body> <div><font face="Arial">Hi all,</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">While the subject of vacuum units is under discussion, a couple of years ago after much frustration with vacs which weren't up to the task, I built my own. Below is a description of the unit I built with image links.</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">The last vacuum we purchased, a 1300W Shop Vac, had three shortcomings.</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">1) the outlet blew down to the floor, so that any dust around the machine would be blown up all around the workshop and over the user.</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">2) The OEM dry element filter was only capable of filtering out house bricks. Everything else went straight through the filter and out into the workshop again.</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">3) When cleaning out our spray room after a spray session, the 'filter' element would be blocked within a minute.</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">My first approach at solving the problem was to buy a Clearvue cyclone and mount it upstream from the vacuum unit. This worked quite well, but soon after the rebuild I dropped it going down the back steps of the workshop, so was forced to do a repair on the cyclone.</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">For those of you who may have come across Bill Pentz, he has spent years working with cyclones and dust collection, and he knows a thing or two on the subject. Here's a link to Bill's website.</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">http://billpentz.com/woodworking/cyclone/index.cfm</font></div > <div><font face="Arial"><br></font></div> <div><font face="Arial">After much reading, I decided that the internal helix that Bill builds into his cyclones was an excellent idea which might be improved by putting in 720 degrees of helix instead of Bill's 360. This would force the incoming air stream to remain laminar for a complete revolution in the cyclone, allowing more time for the dirt to be thrown centrifugally to the outside of the air stream. I built a modified cyclone to incorporate this idea, and made up a new container to house a much larger and more efficient air cleaner element between the cyclone and the vacuum pump. The result is a cyclone/vacuum unit which can collect over fifteen litres of dust while losing very little suction. Its not particularly portable but it does have some grunt. Here are some image links which show the detail of the unit I built.</font></div> <div><font face="Arial"><br></font></div> <div><font face="Arial">For an overview of the unit.</font></div> <div><font face="Arial">http://www.overspianos.com.au/cycvac1.jpg</font></div> <div><br></div> <div>The wand and suction tube are the 50 mm diameter items that came with the original 1300W Shop Vac. The floor tool is a ring-in from one of my previous vacs. The dust collection drum underneath the cyclone is a used 20 litre drum from our lacquer supplier. The vacuum unit and dry-element filter is inside the wooden box, which has an exit hole in the top so that the outgoing air stream is both quieter and directed upwards away from the dirty floor.</div> <div><br></div> <div><br></div> <div>http://www.overspianos.com.au/cycvac2.jpg</div> <div><br></div> <div>A closer view of the cyclone body, showing the 720 degrees of helical baffle inside the body of the cyclone. Note that the incoming air duct is angled to match the helix angle of the internal baffle. This is a Bill Pentz idea and a good one. I've used plumbing fittings for the cyclone-to-filter duct which is larger than the incoming air duct to the cyclone. This reduces air flow losses between the cyclone and the filter drum - besides, plumbing fittings are cheap.</div> <div><br></div> <div>http://www.overspianos.com.au/cycvac3.jpg</div> <div><br></div> <div>This image shows the vacuum head on the drum which houses the filter.</div> <div><br></div> <div>http://www.overspianos.com.au/cycvac4.jpg</div> <div><br></div> <div>The image shows the filter. This filter is a Fleetguard element, which has a relatively large media area, and a very high efficiency with fine dust. This filter doesn't let any of the nasties through Gordon. The OEM trashy filter which came with the original Shop Vac costs $50 while this Fleetguard monster only costs $70 -  a relative bargain.</div> <div><br></div> <div>http://www.overspianos.com.au/cycvac5.jpg</div> <div><br></div> <div>This image shows the shape of the air inlet to the impeller. This was made from a piece of PVC plumbing which was turned down in OD to suit the inlet size of the filter, with the wooden internal block being made from a piece of King Billy Pine, which is very nice wood but its no good for piano soundboards.</div> <div><br></div> <div>http://www.overspianos.com.au/cycvac6.jpg</div> <div><br></div> <div>A close-up of the low-flow-loss inlet profile to the impeller.</div> <div><br></div> <div>http://www.overspianos.com.au/cycvac7.jpg</div> <div><br></div> <div>The important thing about cyclones is that to work efficiently they require a high rotational velocity of the incoming air. If a floor tool is fitted to the end of the wand without some means of allowing by-pass it will kill the air-flow volume and therefore velocity. The hole in the wand provides sufficient floor-tool by-pass volume to allow the maintenance of good airflow velocity into the cyclone. The masking tape is a little hi-tech addition to help the incoming by-pass air to meet the air coming up from the floor tool without causing too much turbulence.</div> <div><br></div> <div>http://www.overspianos.com.au/cycvac8.jpg</div> <div><br></div> <div>After cleaning my workshop and our house after a fortnight's dirt build up. The dust drum is well on the way to being full while the air cleaner has very little visible dirt on it.</div> <div><br></div> <div>http://www.overspianos.com.au/cycvac9.jpg</div> <div><br></div> <div>A close-up of the dirt collected in the drum</div> <div><br></div> <div>http://www.overspianos.com.au/cycvac10.jpg</div> <div><br></div> <div>A close up of the air filter before blowing it clean with a dusting gun. I clean the filter and empty the drum in our spray booth with the down draught fan going. My workshop environment has been transformed by this piece of gear.</div> <div><br></div> <div>If anyone should be interested in building one of these, there is a much higher performance pump available than the one I'm currently using. The best pump I've come across is;</div> <div><br></div> <div>Lamb electric</div> <div>Advantek II - Ultra</div> <div>Model No. 119998-08</div> <div><br></div> <div>To download a data sheet on this motor, go to;</div> <div>http://www.rossbrownsales.com.au/page/motors.html</div> <div><br></div> <div>Scroll down the page, looking at the left side of the page, until you come to a pdf link called "Vacuum Motors Product Catalogue"</div> <div>The fifth motor down from the top of the pdf doc is the Advantek II - Ultra.</div> <div><br></div> <div>This unit has a 1700W motor with two stage pump with properly designed impeller profiles. It sucks a lot harder than the pump I'm currently using (my current pump is capable of picking up 1/2" bolts and nuts from the floor). When my 1300W motor dies, I will replace it with one of these units.</div> <div><br></div> <div>Ron O.</div> <x-sigsep><pre>-- </pre></x-sigsep> <div><font size="+1" color="#0000FF"><b>OVERS PIANOS - SYDNEY</b></font></div> <div><font color="#000000"><i>   </i></font><font color="#0000FF"><i>Grand Piano Manufacturers</i></font></div> <div><font color="#000000">_______________________</font></div> <div><font size="-2" color="#000000"><br></font></div> <div><font color="#000000">Web http://overspianos.com.au</font></div> <div><font color="#000000">mailto:ron@overspianos.com.au</font></div> <div align="center"><font color="#000000">_______________________</font></div> <div align="center"><font color="#000000"><br></font></div> <div align="center"><font size="-1" color="#0000FF"><i>A web page with images of recent work and almost-audio-CD quality mp3 sound files of the Overs piano can be found at;</i></font></div> <div align="center"><font size="-1" color="#0000FF"><i>http://overspianos.com.au/more_info.htm</i></font></div > <div align="center"><font size="-1" color="#0000FF"><i><br></i></font></div> <div align="center"><font size="-1" color="#0000FF"><i>So put on your headphones, plug them into your freshly restarted computer and sit back to over 20 minutes of pure piano.</i></font></div> <div align="center"><font color="#000000"> _______________________</font></div> <div align="center"><font color="#000000"><br></font></div> </body> </html>