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Title: More of Chuckeroo's insanity
Post by: chuckeroo on October 11, 2019, 01:46:58 am
OK a vacuum pump made for a buick supercharger. No not my original idea i'm ripping off someone else's concept. A Buick supercharger because it is self lubricated if i'm not mistaken, nice! a 110 motor hooked up spinning at the right speed, whatever that is. And adapters to go from the supercharger to  valves and finally to the bed. Any one with previous experience please chime in and any suggestions are very welcome. How am i going to keep the wood chips out of the blower vanes ? A filter of some kind perhaps? The fellow out of Southern California that posted this idea also posted vacuum numbers and if i'm not mistaken they were impressive. Talk about on the cheap right. Under a hundred bucks for the supercharger. Pick a part special. Think i'll go get one this weekend.


Title: Re: More of Chuckeroo's insanity
Post by: Bob La Londe on October 11, 2019, 01:59:46 am
OK a vacuum pump made for a buick supercharger. No not my original idea i'm ripping off someone else's concept. A Buick supercharger because it is self lubricated if i'm not mistaken, nice! a 110 motor hooked up spinning at the right speed, whatever that is. And adapters to go from the supercharger to  valves and finally to the bed. Any one with previous experience please chime in and any suggestions are very welcome. How am i going to keep the wood chips out of the blower vanes ? A filter of some kind perhaps? The fellow out of Southern California that posted this idea also posted vacuum numbers and if i'm not mistaken they were impressive. Talk about on the cheap right. Under a hundred bucks for the supercharger. Pick a part special. Think i'll go get one this weekend.

Well... stock cars turn up to a little over 9000 RPM if they are properly balanced.  I imagine a dragster with a super charger might be atleast in the same range.  Find a few picture and compare the size of the super charger pulley with the size of the engine pulley/balancer.  Or.... look up the manufacturer's website and see what they say. 


Title: Re: More of Chuckeroo's insanity
Post by: dh42 on October 11, 2019, 02:11:29 am
Hello

Quote
How am i going to keep the wood chips out of the blower vanes ? A filter of some kind perhaps?

On my vacuum pump, the filter is done with a grid tube and a foam ... maybe a filter for bike can do the trick ?

++
David


Title: Re: More of Chuckeroo's insanity
Post by: chuckeroo on October 11, 2019, 18:40:21 pm
Thanks for the input guy's, 9,000 rpm whoa doggie i don't think this will be neccessary. But it sounds good though. Talk about flying parts!!!


Title: Re: More of Chuckeroo's insanity
Post by: chuckeroo on October 11, 2019, 22:55:58 pm
WHOA just hit 9,000 rpm and this thing is sucking like a whore on bourbon street.


Title: Re: More of Chuckeroo's insanity
Post by: lloydsp on October 11, 2019, 23:31:35 pm
Well... I've spent a bit of time cruising Bourbon Street, but never got sucked! <grin>

('Had some GREAT seafood at Felix's on Iberville St. [which butts up to Bourbon St], though!!!)

Lloyd


Title: Re: More of Chuckeroo's insanity
Post by: dave benson on October 11, 2019, 23:50:43 pm
HI Chuck
Before you get too carried away,  go here https://www.physicsforums.com/threads/supercharger-power-requirement.395212/page-2 (https://www.physicsforums.com/threads/supercharger-power-requirement.395212/page-2) to the second page, and at the last post it gives you the required HP to drive one of these superchargers.
It'll cost you an arm and a leg to run  electricity wise.

What about one of these: https://www.youtube.com/watch?v=S5ryW5Fm_Sc  (https://www.youtube.com/watch?v=S5ryW5Fm_Sc)
There are plenty of DIY builds on youtube. Cheap and easy to build and a lot cheaper to run comparatively.

Dave


Title: Re: More of Chuckeroo's insanity
Post by: Garyhlucas on October 12, 2019, 00:30:18 am
Hello

Quote
How am i going to keep the wood chips out of the blower vanes ? A filter of some kind perhaps?

On my vacuum pump, the filter is done with a grid tube and a foam ... maybe a filter for bike can do the trick ?

++
David

David, that isn’t a filter it’s a silencer only. I have installed maybe 50 of those.  The style you have is fairly tolerant of small chips. A Gast type would have siezed on you already.  However you really should have an intake filter, the bigger the better.


Title: Re: More of Chuckeroo's insanity
Post by: Garyhlucas on October 12, 2019, 00:46:29 am
Chuck,
A super charger is positive displacement lobe blower and is very efficient compared the regenerative blower David has. I’ve installed maybe 30 of these. They are mostly belt driven so they can match the air requirements. So you can run it slower and use much less hp. There is a caveat depending on how it is lubricated as there is a timing gear set on one end. If it has splash lube they typically can’t go below 30% of base speed without problems. Blowers that need to run slow often have lube pumps. So your idea could work very well.  Also the power requirements can be much less when used for vacuum not pressure.


Title: Re: More of Chuckeroo's insanity
Post by: dh42 on October 12, 2019, 03:16:18 am
Re

Quote
David, that isn’t a filter it’s a silencer only.

Ah OK.

So I have (I had) no filter ... except the small holes of the vacuum table itself ...

++
David


Title: Re: More of Chuckeroo's insanity
Post by: dave benson on October 12, 2019, 08:58:20 am
HI Chuck
I tried to find a video of someone else doing this, to see what their impressions were or if they did any tests, but came up empty handed, I did however find this https://www.youtube.com/watch?v=zuXnEIj3g5s (https://www.youtube.com/watch?v=zuXnEIj3g5s) where the guy puts his hand over the outlet and inlet ports when it was running at 3000 rpm. Buick V6 M90
Over the outlet he could stall the motor, over the inlet he separated his fingers and it did produce some
suck,but as you can see not a lot really compared to the noise it made.

Many years ago I serviced Hydra-vane and Champion rotary screw compressors, Factory duty mainly
some mobile Hydra-Vanes for Jack Hammer Duty, Ford 6 cyl diesel powered. Here is a link to their website https://www.championairtech.com/en/products/screw-compressors/ka-ka-plus-series
for the smallest screw compressor they make 2.2kw (3HP) @ 10 bar they rate 0.24 cubic metres.
That's a state of the art machine specificity designed for the job, and that's not a lot of performance
So I think using a second hand one out of a car from a car wreckers may be a problem without a good going over.

Second the noise is horrendous. even with a filtering system it might need to be ran outside of the shop. Even then the neighbours might run you out of town.

Third the filtering would have to be excellent and maintained often. Religiously
At the speeds I saw the guy in the video run it at 3000 rpm, you would have to force lube the bearings  to keep them cool if running it for a while.

Can you do this, well  yeah sure you can do anything especially if your a Gear Head this might garner you some cachet with the brethren or at least put a wry smile on their faces, but will it be as efficient as a Politician at turning 'Dollars into Vacuum', I'm not so sure....I think for you in the home shop, with one router  this would be marginal value proposition at best. Might be fun though.

In any case if you start a built then post some pic's here it would be interesting to see how you go.

Dave
Edit:
https://www.pneumatictips.com/whats-efficient-reciprocating-compressor-screw-air-compressors/
Just found this and it Tally’s with my recollections about maintaining these beasties.
From Here:
To compare the two types of compressors, the math works like this:
For a 10 cfm load, a 100 cfm 25 hp (21.3 kW at full load) screw compressor consumes 21.3 kW for 10% of the time (2.1 kW) and 7.4 kW for 90% of the time (6.7 kW). This means the total average power consumption is 8.8 kW to produce 10 cfm, a specific power of 88 kW per 100 cfm.

A similar sized 25 hp reciprocating compressor that, say, can produce only 90 cfm at 21 kW, runs 11% of the time to feed the same load (2.3 kW) but consumes no power when it is not producing air. This works to a total average power of 2.3 kW or a specific power of 23 kW per 100 cfm—almost 4 times more energy efficient!


Title: Re: More of Chuckeroo's insanity
Post by: Garyhlucas on October 12, 2019, 18:57:04 pm
Dave,
Your math is faulty. Screw compressors are replacing reciprocating compressors for two reasons, higher efficiency and way longer life. Lobe blowers aka superchargers are a good choice and efficient for lower pressures typically 15 psi and high volumes. The best lobe blowers have 3 lobes that helical which greatly reduces pulsation and noise. I am not sure what is in a car supercharger.


Title: Re: More of Chuckeroo's insanity
Post by: chuckeroo on October 12, 2019, 22:14:58 pm
Time to do some research .Realistically speaking it's a small area i would like to use this with. About 14x40 not really that big. Saw a video on you tube the guy goes by CNCNUTZ and he has a full desription from beginning to end on how he put his together.Don"t have a link at this second but this will get you there. SO the question is in the real world how much vacuum level needs to be maintained before the wood goes a flyin, and yes i know there is a number for perfect vacuum and that's not what i'm trying to attain here, just hold it in place and i realize that this comes down to a guess. Maybe a percentage of loss versuses usable levels in the startup of the pump with no loss at that point in time. The prior info i picked up on the guy was using a 110 motor how many horsepower don't know and i wish i did. Thanks for the food for thought!!! Keep it coming.


Title: Re: More of Chuckeroo's insanity
Post by: lloydsp on October 12, 2019, 23:02:26 pm
Chuck,
I have a (nominal) 4x8 foot bed router. I have to maintain about 10" Hg per square-inch of vacuum in addition to edge clamping, in order to keep work from moving about.  And it still does, rarely, to the ruin of the job.

To accomplish that, I have a 20 HP 240V-3 phase regenerative vacuum blower.  It consumes a great deal of power.

Lloyd


Title: Re: More of Chuckeroo's insanity
Post by: dave benson on October 13, 2019, 14:42:45 pm
Garry
Thankfully the Math is not mine and  is ok, what's implicit in the math and not stated very clearly in the article is that  a typical installation for rotary vane compressors is for Uber air regulation to supply and protect capital plant, and  in  this configuration all pumps running and bypassing  to provide the quickest response time and are plumbed in directly to the machine, no receiver which would act like a big spring. So with the pumps continuously on and bypassing just waiting to respond to an event it's just a costly but necessary process.

I think what your getting at is you install 3ph rotary vane compressors connected to a receiver just like a piston powered one with the ability to turn on and of thus saving money as compared to a blower or piston powered pump. I don't know never looked into it.

Chuck as to the motor size, if you are happy with CNCNuts tables holding power with the newspaper trick it seemed to hold pretty well, he mentioned that he was using a Festool vacuum designed for the task as the motor cooling was done by a separate fan not the airflow from the incoming air so I had a look at the catalogue and selected one almost the same his must be older anyway the power quoted was 2kw, that's a little under 3 HP.

First thing to check  once you get the unit and the motor is how hot the bearings  are running, I use a non contact IR thermo to check my spindles and if you have one $30 it's easy to check.

After that sort out the filter, remember as you are using it to pull a vacuum anything not filtered out goes through the blades, maybe one of those cyclone filters and then a free flowing filter of some kind, and a free flowing exhaust system that cuts the noise down.

Dave


Title: Re: More of Chuckeroo's insanity
Post by: Garyhlucas on October 13, 2019, 18:11:26 pm
A big factor on power require for vacuum hold down is leakage rate. If the leaks are small or non-existant the power requirements can be low. I hold down metal and plastic parts on a gasketed plate and I get about 13 pounds of force per sq.in.

Lloyds vacuum is likely a regenerative blower. It will use 20 hp at wide open air intake but once a part is clamped tight a wattmeter, not an ampmeter would show it using maybe 5 hp. I build waste treatment plants using these blowers and we have power logging from the VFD that runs every blower.

So a positive displacement lobe or screw blower on a VFD would be an optimum system providing the most grip for the least power.


Title: Re: More of Chuckeroo's insanity
Post by: lloydsp on October 13, 2019, 21:22:23 pm
Yeah, Gary... I SAID it was a regenerative blower! <grin>

I've not measured the power while clamping, but the best I can get is 10" Hg vacuum, even with parts clamped-down tight.  I've also not measured the 'down-force' that creates.

Perhaps, with your experience with such machines, you can tell me how much hold-down force I get per square-inch on material at that vacuum level.  I'd really like to know (no kiddin').

Thanks,
Lloyd


Title: Re: More of Chuckeroo's insanity
Post by: chuckeroo on October 13, 2019, 21:29:11 pm
Thanks dave i will keep all of this in mind.


Title: Re: More of Chuckeroo's insanity
Post by: lloydsp on October 13, 2019, 22:09:50 pm
'Couldn't avoid looking up the data!  At 10" Hg vacuum, I'm gettin 4.904psi on the worksheet.

Lloyd


Title: Re: More of Chuckeroo's insanity
Post by: Garyhlucas on October 14, 2019, 18:16:32 pm
Lloyd,
Yep that is a right and about the best you can expect from regenerative blower. On plastic with a rubber gasket using a venturi vacuum pump run by compressed air I can get about 25” hg. Venturi generators are very inefficient and only work well with small volume requirements.


Title: Re: More of Chuckeroo's insanity
Post by: dh42 on October 14, 2019, 23:10:26 pm
Hello

hg ?

Hectogram or inch (or mm) of mercury ?   ??? ???

++
David


Title: Re: More of Chuckeroo's insanity
Post by: Garyhlucas on October 14, 2019, 23:21:45 pm
Sorry inches of mercury.


Title: Re: More of Chuckeroo's insanity
Post by: lloydsp on October 15, 2019, 01:40:52 am
David,
Not for nothing, but he WROTE 'inches of mercury', when he noted '...25" hg...'.

Those are the English language conventions for inches ("), and (except for capitalization) mercury (Hg).

He wrote - in English - exactly and precisely-understandable information for a native English speaker/reader.

Just sayin'! (Ain't Engrich strange?)

<grin>

Lloyd


Title: Re: More of Chuckeroo's insanity
Post by: dave benson on October 15, 2019, 05:24:18 am
Lloyd you seem you be doing ok, I compared the watts\p\Mbar of david's pump and  the one I think CNCnuts is using and it works out on paper at least, that your machine is capable of 40x the force.

I made a comparison between the vacuum cleaner,David's pump, and Lloyds pump, where the expectation was that all of the pumps (same type but very different configurations) would return a figure close to, or equal in value.

0.7 kw at 0.240 Mbar   vacuum cleaner
0.7 kw at 0.250 Mbar    David's Pump
0.7 kw at 0.280 to 0.338 Mbar   Lloyds 
(The devil in the detail here is David's pump cost's half as  much to run as compared to the vacuum cleaner so David's on a winner there).
That's pretty good measuring Lloyd your numbers are close, I suspect that's within the tolerance of what you measured it with.
I didn't know what you really needed and went and had a look at what the manufacturer (shopsabre) recommended Here:

https://beckerpumps.com/pressure-pumps/rotary-vane-pumps-pressure-pumps/oil-less-compressors/the-dtlf-series/ (https://beckerpumps.com/pressure-pumps/rotary-vane-pumps-pressure-pumps/oil-less-compressors/the-dtlf-series/)

Your pump seems to meet the requirements and is not overly constricted or blocked either, or the numbers above would be in the toilet.
Could be blocked galleries in the table?

How have you determined that the table is not performing correctly.

F=P\A Force\Area pascals\sqm Pressure (Pascals) Area exposed to vacuum in (sqm).

Dave


Title: Re: More of Chuckeroo's insanity
Post by: EddyCurrent on October 15, 2019, 07:40:04 am
David,
Not for nothing, but he WROTE 'inches of mercury', when he noted '...25" hg...'.

Those are the English language conventions for inches ("), and (except for capitalization) mercury (Hg).

He wrote - in English - exactly and precisely-understandable information for a native English speaker/reader.

Just sayin'! (Ain't Engrich strange?)

<grin>

Lloyd

Here in England, inches of mercury or 25"hg all make perfect sense to me but I'm from the pre decimal era  :D
plus my old stick barometer literally has a long column of mercury and the scale is in inches.

I just saw this though;

"Millibar
International unit for measuring air pressure. Now a hectoPascal (hPa) is the standard unit for pressure."




Title: Re: More of Chuckeroo's insanity
Post by: lloydsp on October 15, 2019, 12:52:15 pm
Eddy,
The more 'technical' one becomes, the more likely it is you'll use millibars.  As a pilot, I was getting pre-flight briefings from the Federal Aviation Authority in both inches of mercury and millibars, as far back as the mid 1970s.

Here in the US, the "common man's" unit is still inches of mercury, but millibars is creeping into daily language.

My table is fine, but the nature of the work requires that I have a 1/4" sheet of de-surfaced low-density fiberboard as the 'waste sheet'.  That cuts WAY down on the available hold-down of the work-piece itself.  Unfortunately, we must cut all the way through the work-piece over a large area of every job we run, so 'no backer' is not an option.

My blower is an Italian model -- something like "ZPV" or "VPZ".  I haven't looked at the tag in a year.  But I DO have a $5800 USD 'spare' sitting in the corner, lest something happen.

Lloyd


Title: Re: More of Chuckeroo's insanity
Post by: Garyhlucas on October 15, 2019, 14:14:08 pm
Lloyd,
I have worked with the Blower you have. It is a nice very well made unit, however make sure you have a good intake filter as it is one of the designs that does NOT tolerate any debris or it siezes up!  After siezing up 3 of them a couple of times each we finally figured out that in our pressure application short power failures were deadly.

The Becker blower referred to is another animal altogether. It is a positive displacement blower so the efficiency is high but unlike the lobe blower there is rubbing of the vanes against the housing so their maintenance is higher and life span is much shorter. They aren’t used in our business because we run blowers 24/7/365 until they need a rebuild. That’s just bearings on a regenerative, and might be gears as well on a lobe blower after lots of hours.

Screw blowers are getting more popular in our industry and now Turbo Blowers turning more than 20,000 rpm running on air or magnetic bearings!


Title: Re: More of Chuckeroo's insanity
Post by: lloydsp on October 15, 2019, 17:38:26 pm
Ah... 'looked at the tag.  It's an FPZ 20HP unit.

Yes, we thoroughly filter the incoming air, and have a good filter on the vacuum-relief valve, also.  Because we sort-of 'pre-filter' the air through LDF, we check the filters monthly, but have only had to clean/replace them three times in its life.

This unit's got more than a decade of use, and the bearings still seem fine.  But like I said, there's a spare on the shelf, if it decides to upchuck.  When the theme parks call, you can't afford any down-time.

Lloyd


Title: Re: More of Chuckeroo's insanity
Post by: Garyhlucas on October 15, 2019, 18:59:19 pm
Lloyd,
Yes I knew you were think FPZ.  A decade of your use is likely only a year of ours.  So you are probably good for another 20 years!


Title: Re: More of Chuckeroo's insanity
Post by: lloydsp on October 15, 2019, 19:12:42 pm
That's good to know, Gary.  Thanks!

Lloyd


Title: Re: More of Chuckeroo's insanity
Post by: dh42 on October 15, 2019, 23:02:52 pm
David,
Not for nothing, but he WROTE 'inches of mercury', when he noted '...25" hg...'.

Those are the English language conventions for inches ("), and (except for capitalization) mercury (Hg).

He wrote - in English - exactly and precisely-understandable information for a native English speaker/reader.

Just sayin'! (Ain't Engrich strange?)

<grin>

Lloyd

Hello

Yes, sorry, I don't paid attention to the " ... :-[ ... on the document I've quickly read they don't use the same symbol (inHg instead Hg") ...

Quote
International unit for measuring air pressure. Now a hectoPascal (hPa) is the standard unit for pressure."

On my pump (side channel blower) the manufacturer give the value in mbar (-330 mbar for mine) ....  and on some documents they don't give the depression produced by the pump but the pressure that remain when the pump is running (vane pump) ... and it's is given in Pa ...

++
David


Title: Re: More of Chuckeroo's insanity
Post by: dave benson on October 16, 2019, 10:14:59 am
Yes I avoid unit conversion between the various systems like the plague. spacecraft have been crashed like this. ::)
David, say in a few years that you would like to upgrade to a newer more powerful system and have selected a few pumps as likely candidates based on some criteria,physical size shape,capacity, and cost to run and are wondering how to objectively compare them apples to apples so that you can decide which pump is best suited to your application. Say your looking for Efficiency, notice in the table that all the power figures are 0.7 Kw even though Lloyds pump is 20 Hp. It's only comparing pump efficiency. This is the Apples to Apples  thing. :)

Well it's easy, the nice folks at the European and other standards organisations have laid out a series of tests so that you can do this and to meet this standard and to be able to put the sticker of compliance on the pump, manufacturers publish this data both the vacuum cleaner and your pump is the data I used from their websites not the info that would be on the pump.  Festool publish there specs in pascals not Mbar which is nice of them.

Have a look at this page if you are interested knowing more.
https://www.engineeringtoolbox.com/centrifugal-pumps-standards-d_1116.html (https://www.engineeringtoolbox.com/centrifugal-pumps-standards-d_1116.html)
https://www.engineeringtoolbox.com/horsepower-d_472.html (https://www.engineeringtoolbox.com/horsepower-d_472.html)
The ISO standards look here  as an example https://www.iso.org/standard/17788.html  (http://The ISO standards look here  as an example https://www.iso.org/standard/17788.html)

As to the spoil board I sat there in disbelief that CNCNutz threw the spoil board on the table and then threw a piece of al maybe 100mmx100mmx3mm on top of the spoilboard  at first it was reasonably easy to move and then after adding the newspaper had a moderately hard time to slide it across the table He's not big guy and hasn’t seen the Gym in a while so the 25 kg force I had guesstimated  acting on the plate seems not to far out of the realms of possibility.
At this stage Chuck I think you will have to keep the cutting forces fairly modest.
Maybe stick to 3 mm tools or less for the smaller pieces.

There will be a minimum size for the work piece to hold securely,  for milling Al I would guesstimate this would be in the range of 200 mm x 200 mm.

I found this from  Festool, the spec's for a vacuum table running at 0.150 Mbar  without a spoil plate, so multiplying up the figures to 250 Mbar multiplying by "the efficiency" of the spoil backing, I took a WAG here (0.6)  I figure the first piece you cut should start out at 200 mm x 200 mm  but to find  the minimum size, you're just going to have to experiment.

Dave