On Mon, 16 Feb 2015 13:45:25 -0500, "Jim Wilkins"
wrote:

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
.4.170...
"Jim Wilkins" fired this volley in
news:mbt9mu$pih$1
@dont-email.me:

A buried pipe is supported against bulging out at right angles to
where the collapse begins. Yours wasn't.

Exactly how does that address "five story high vertical column
separation"?

This stuff is not used only buried. It's approved (in some few
places) for
vertical vents on DWV systems.

Lloyd

How can you pull a five story (50') vacuum?

Vertical column separation dynamics are about the water hammer that
follows. It pertains mostly to tall pipes and to a failure of an
upstream valve or pump.

If the column is water, the pressure inside can't drop below the vapor
pressure of water -- around 20 torr (20 mmHg) at room temperature.


The rating may be for the overpressure from a five story high water
hammer.
http://en.wikipedia.org/wiki/Water_hammer
Google isn't too helpful.

-jsw

Ed Huntress fired this volley in
:

If the column is water, the pressure inside can't drop below the vapor
pressure of water -- around 20 torr (20 mmHg) at room temperature.

Ah, but it can drop lower than that -- instantaneously. It's rapidly
followed by "makeup" by the vapor pressure of the water; but there's time
involved in that's happening.

Lloyd

Ed Huntress fired this volley in
:

I should have said that I understand it's an asymptotic relationship at low
rates of fall, but with 'overshoot' when the fall is rapid, like when the
water is _already_ falling at acceleration and then the pipe gets stopped-
up.

LLoyd

On 16/02/15 18:10, Jim Wilkins wrote:
"Tim Wescott" wrote in message
...
On Mon, 16 Feb 2015 07:37:26 -0800, Larry Jaques wrote:

On Mon, 16 Feb 2015 00:15:52 -0600, Tim Wescott
wrote:

On Sun, 15 Feb 2015 21:15:01 -0600, Lloyd E. Sponenburgh wrote:

technomaNge fired this volley in
news:mbrmo8$pa3$1 @dont-email.me:

s that similar to circular mills?
For example, 2 24 gage wires twisted together will carry the
same
maximum current as 1 21 gage.
Same concept. Only, ShopSabre used the logic thus:

"If it takes a 12-gauge wire to go 12 feet, then I should be able
to
run 36 feet with only 36 gauge wire! We'll save LOTS of money!"
There was an engineer involved in there someplace, I know it.
By the book and never in the field before, no doubt.
Engineers, the 2nd Louies of manufacturing!
You're being too hard on engineers, because you don't notice when we
succeed in some stunningly creative way. It's just that when we
fail,
it's often in some stunningly creative way.

--
www.wescottdesign.com
Young engineers tend to an arrogant self-confidence not supported by
their practical experience. As lab manager I had to tactfully show
them that they still had very much to learn, while respecting what
they did know.

For example one of them kept requesting another case of Polaroid film
for the scope camera. When I finally asked why he told me he was
attempting to determine how fast a fuse would blow to protect his
circuit. His schooling hadn't covered real-world device
characteristics, or apparently how to least-squares fit a curve to
noisy data points.

So I gave him a brochure that explained the subtleties of fuse
ratings.
http://www.socfuse.com/products/pdf/P178-P188_E.pdf

-jsw


I used to work with a couple of guys with electrical/electronic
engineering degrees and yet when it came to practical stuff I got asked
to look at it as I had more practical experience with electronics and my
background is mechanical engineering. One did admit that will he may
have been able to design a transistor from scratch but he didn't know
what to do with it when he had. Another electronics graduate mentioned
that he wasn't aware that capacitors came in varying ESR grades until he
looked into why some circuits weren't performing as expected, maybe he
hadn't been paying attention in class.

In article 0,
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote:

yep... and to the 'engineer' who suggested I pull 30" and wait to see what
happens.

Ehhh.... I'm reluctant to do that here in Florida. I think I'll stop at
about 29.96".

LLoyd

Indistinguishable on the relevant dial gauge...

Also perfectly achievable on any day with a high pressure system in
place, at least in Florida, where 345 feet is as far above sea level as
you can get. At about the time you wrote this, 30.19 inches at KOBE...a
"standard" atmosphere is an agreed upon average, not something the
actual atmosphere has to comply with. Might be a tad more impossible in
Denver.


http://w1.weather.gov/data/obhistory/KOBE.html

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

On 16/02/15 13:16, Lloyd E. Sponenburgh wrote:
Tim Wescott fired this volley in
:

There was an engineer involved in there someplace, I know it.
yep... and to the 'engineer' who suggested I pull 30" and wait to see what
happens.

Ehhh.... I'm reluctant to do that here in Florida. I think I'll stop at
about 29.96".

LLoyd
I was being shown around a local workshop making high end souvenir
models and one of the workers said how the vacuum degassing chamber
could pull 2 atmospheres, I just looked at my mate as he looked at me
and we both knew it wasn't worth commenting on so let it pass.
Theoretically possible if you have a hyperbaric chamber for the initial
mixing but unlikely.

I'm looking to use an old compressor tank, or half of it, as a vacuum
degassing chamber and have pulled about 0.95 atm on it with no problem
but it is a reasonably heavy wall tank. Comments online I noted say that
failures of vacuum chambers are rarely spectacular when they collapse
but then the comments were about ductile materials such as steel which
just crumple.

David Billington fired this volley in news:mbtho2$1as$1
@dont-email.me:

Comments online I noted say that
failures of vacuum chambers are rarely spectacular when they collapse
but then the comments were about ductile materials such as steel which
just crumple.


And so does 'fresh' PVC. I wouldn't bet on the results with 10-year-old
stuff the plasticizers had gassed out of.. G

LLoyd

On Mon, 16 Feb 2015 13:15:43 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Ed Huntress fired this volley in
:

If the column is water, the pressure inside can't drop below the vapor
pressure of water -- around 20 torr (20 mmHg) at room temperature.

Ah, but it can drop lower than that -- instantaneously. It's rapidly
followed by "makeup" by the vapor pressure of the water; but there's time
involved in that's happening.

Lloyd

Well, 20 torr is only about 0.4 psi absolute. So the difference is
insignificant.

--
Ed Huntress

Ed Huntress fired this volley in
:

Well, 20 torr is only about 0.4 psi absolute. So the difference is
insignificant.

Apparently, you've never manned a firefighting rig!

That 'overshoot' I was talking about can go up to 8 psi under the right
circumstances.

Lloyd

Ed Huntress fired this volley in
:

Well, 20 torr is only about 0.4 psi absolute. So the difference is
insignificant.

Oh... you you missed the most basic point. Yep... 20 torr IS about .4 psi,
absolute.... figure that FROM 14.7-odd psi atmospheric.

G
Lloyd

On Mon, 16 Feb 2015 14:25:31 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Ed Huntress fired this volley in
:

Well, 20 torr is only about 0.4 psi absolute. So the difference is
insignificant.

Apparently, you've never manned a firefighting rig!

Well, that's true. The closest I ever came was fixing a pump motor for
the volunteers in my old town, 40 years ago.


That 'overshoot' I was talking about can go up to 8 psi under the right
circumstances.

We're miscommunicating. The pressure can only drop an addition 0.4 psi
from the pressure with fully-water-saturated "vacuum." That's all the
"overshoot" that's physically possible.

--
Ed Huntress


Lloyd

On Mon, 16 Feb 2015 14:26:35 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Ed Huntress fired this volley in
:

Well, 20 torr is only about 0.4 psi absolute. So the difference is
insignificant.

Oh... you you missed the most basic point. Yep... 20 torr IS about .4 psi,
absolute.... figure that FROM 14.7-odd psi atmospheric.

G
Lloyd

Let's try this again. When the water column separates, the water vapor
pressure would allow the absolute pressure to drop to 0.4 psi. That's
14.3 psi LESS than atmospheric.

When a column separates, the gas pressure in that bubble consists only
of the water-vapor pressure (or the vapor pressure of whatever liquid
was in there.)

Are we on the same page?

--
Ed Huntress

Ed Huntress fired this volley in
:

We're miscommunicating. The pressure can only drop an addition 0.4 psi
from the pressure with fully-water-saturated "vacuum." That's all the
"overshoot" that's physically possible.

Ok... I understand that is all the overshoot possible, but the absolute
pressure within that vertical pipe can be drawn down by the falling water
TO 0.4 psi (at 'room temperature' theoretically). That's pretty close to
14-1/4 psi of vacuum relative to atmospheric.

LLoyd

Ed Huntress fired this volley in
:


Let's try this again. When the water column separates, the water vapor
pressure would allow the absolute pressure to drop to 0.4 psi. That's
14.3 psi LESS than atmospheric.

When a column separates, the gas pressure in that bubble consists only
of the water-vapor pressure (or the vapor pressure of whatever liquid
was in there.)

Are we on the same page?


Yes, exactly. What you just stated was precisely what I was trying to
express... that the vacuum within the pipe would well-exceed that
necessary to completely collapse it (sans surrounding 'soil support').

Somehow I mistook you to mean that the pressure could only _drop_ by 20
torr... sorry.

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 4.170...
Ed Huntress fired this volley in
:

We're miscommunicating. The pressure can only drop an addition 0.4
psi
from the pressure with fully-water-saturated "vacuum." That's all
the
"overshoot" that's physically possible.

Ok... I understand that is all the overshoot possible, but the
absolute
pressure within that vertical pipe can be drawn down by the falling
water
TO 0.4 psi (at 'room temperature' theoretically). That's pretty
close to
14-1/4 psi of vacuum relative to atmospheric.

LLoyd

So far so good. How does 'five stories' relate to that?

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in
. 4.170:

I've dug around for quite a while, and although I find all sorts of
"comforting" diagonal data about fall heights, column separation, etc, I
cannot find a stated vacuum rating for ASTM D2729 pipe (4").

I'm getting ready to re-do a poorly-designed vacuum hold-down system for
a ShopSabre 4896 that has only ONE 2" pipe to each half of the table,
even though the pump has a 4" inlet!(duh!)

4" water pipe (sch 20-40-80) is slightly too large to fit in the space
provided, but 4" ASTM-D2729 sewer pipe will fit. We're only talking 11"
of vacuum (or -5.4psi). But I want some margin of safety, and can't find
a figure anywhere.

Anyone know?

Lloyd, I don't know of an official vacuum rating for this pipe, but I do have first-hand
experience using D2729 sewer pipe in vacuum applications. A couple of years ago, I built
the system shown here
http://www.veneersupplies.com/pages/...um__Press.html
as the vacuum engine for a woodworking veneer press, using D2729 pipe for the twin
vacuum chambers. I've repeatedly cycled this system to 21" of vacuum, including a couple
of pressings a year ago where it held that vacuum for four hours at a time.

And I've had no problems at all -- which would suggest that you probably have about a 2x
margin of safety.

Doug Miller fired this volley in
:

And I've had no problems at all -- which would suggest that you
probably have about a 2x margin of safety.

Doug, my sample collapsed at about 11". I'm sure vendors' products vary.

Lloyd

On Mon, 16 Feb 2015 17:04:06 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Doug Miller fired this volley in
:

And I've had no problems at all -- which would suggest that you
probably have about a 2x margin of safety.

Doug, my sample collapsed at about 11". I'm sure vendors' products vary.

Lloyd

What's the diameter of Doug's pipe? Smaller diameters could handle a
lot more vacuum.

--
Ed Huntress

Ed Huntress fired this volley in
:

What's the diameter of Doug's pipe? Smaller diameters could handle a
lot more vacuum.

Yup.
L

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in
. 4.170:

Ed Huntress fired this volley in
:

What's the diameter of Doug's pipe? Smaller diameters could handle a
lot more vacuum.

4", same as Lloyd's. Mine is in sections only about 15" long, though, which probably accounts
for the difference in our results.

On Tue, 17 Feb 2015 00:07:49 +0000 (UTC), Doug Miller
wrote:

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in
.4.170:

Ed Huntress fired this volley in
:

What's the diameter of Doug's pipe? Smaller diameters could handle a
lot more vacuum.

4", same as Lloyd's. Mine is in sections only about 15" long, though, which probably accounts
for the difference in our results.

That certainly would allow more vacuum than the longer lengths, but
the calculations are beyond me.

--
Ed Huntress

Doug Miller fired this volley in
:


4", same as Lloyd's. Mine is in sections only about 15" long, though,
which probably accounts for the difference in our results.

Probably does, but I needed to test the 8' length I'd need for the
collector. Shorter would be better, if I could use it.

LLoyd

On Mon, 16 Feb 2015 19:37:10 +0000, David Billington wrote:

Another electronics graduate mentioned
that he wasn't aware that capacitors came in varying ESR grades until he
looked into why some circuits weren't performing as expected, maybe he
hadn't been paying attention in class.

That's definitely not something you learn in class -- you get that after
you're fending for yourself in industry.

A good engineering education should teach you the basics, and how to learn
anything on top of that, but cannot, of necessity, do much of the "on top
of that", because it takes decades.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

"Tim Wescott" wrote in message
...
On Mon, 16 Feb 2015 19:37:10 +0000, David Billington wrote:

Another electronics graduate mentioned
that he wasn't aware that capacitors came in varying ESR grades
until he
looked into why some circuits weren't performing as expected, maybe
he
hadn't been paying attention in class.

That's definitely not something you learn in class -- you get that
after
you're fending for yourself in industry.

A good engineering education should teach you the basics, and how to
learn
anything on top of that, but cannot, of necessity, do much of the
"on top
of that", because it takes decades.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I tried to learn the detail that electrical engineers don't get in
school. Much of it is easily available in application notes IF you
first know you need them. I found no central index to all electronic
wisdom.
http://www.analog.com/library/analog.../archives.html

In Chemistry we took a semester class on how to hunt down practical
details.

-jsw

On Mon, 16 Feb 2015 10:32:59 -0600, Tim Wescott
wrote:

On Mon, 16 Feb 2015 07:37:26 -0800, Larry Jaques wrote:

On Mon, 16 Feb 2015 00:15:52 -0600, Tim Wescott
wrote:

On Sun, 15 Feb 2015 21:15:01 -0600, Lloyd E. Sponenburgh wrote:

technomaNge fired this volley in
news:mbrmo8$pa3$1 @dont-email.me:

s that similar to circular mills?
For example, 2 24 gage wires twisted together will carry the same
maximum current as 1 21 gage.

Same concept. Only, ShopSabre used the logic thus:

"If it takes a 12-gauge wire to go 12 feet, then I should be able to
run 36 feet with only 36 gauge wire! We'll save LOTS of money!"

There was an engineer involved in there someplace, I know it.

By the book and never in the field before, no doubt.
Engineers, the 2nd Louies of manufacturing!

You're being too hard on engineers, because you don't notice when we
succeed in some stunningly creative way. It's just that when we fail,
it's often in some stunningly creative way.

That they do. But they're SOOOOOOO easy to fiddle with, y'know?

I truly love engineers, giving me so many neat things to play with.


--
A sound mind in a sound body is a short but full description
of a happy state in this world.
-- John Locke

On Sunday, February 15, 2015 at 3:49:07 PM UTC-6, Lloyd E. Sponenburgh wrote:
I've dug around for quite a while, and although I find all sorts of
"comforting" diagonal data about fall heights, column separation, etc, I
cannot find a stated vacuum rating for ASTM D2729 pipe (4").

I'm getting ready to re-do a poorly-designed vacuum hold-down system for
a ShopSabre 4896 that has only ONE 2" pipe to each half of the table,
even though the pump has a 4" inlet!(duh!)

4" water pipe (sch 20-40-80) is slightly too large to fit in the space
provided, but 4" ASTM-D2729 sewer pipe will fit. We're only talking 11"
of vacuum (or -5.4psi). But I want some margin of safety, and can't find
a figure anywhere.

Anyone know?

Thanks,
Lloyd

If it helps and you want to calculate it yourself --
https://cds.cern.ch/record/1046848/files/p31.pdf
See section 3.3 on calcs for tubes.

On Mon, 16 Feb 2015 10:35:04 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Well, it cost me a double-sawbuck to figure out what I needed to know,
but it leaves me questioning some of the manufacturer's claims.

I took a length of good, clean, and round 2927 pipe (no Larry, no
holes... this is solid pipe),

clap,clap,clap


capped both ends, BRACED the ends inside so
they could not initiate a collapse, and stuck in a reefer fitting for my
Robinaire pump... then started gradually pulling it down.

drum roll, please


Now, three of the manufacturers of the stuff claimed "ability to
withstand column separation up to five stories high". Working backwards,
a suddenly-separated column of water-borne 'stuff' would initially pull a
vacuum of about 22", before it began to boil and make up the vacuum.

So I felt pretty good about getting through this OK. nahhh.... at about
18", the whole pipe gently folded up into a flat ribbon of PVC, with only
the braced ends staying round. G (kinda neat to watch, even though that
was the expected failure mode)

Well, at least you know how to make PVC bows without a vise or torch
now.


So, I'm going to have to find room for two runs of 3" Sch-40 under the
table for each of the four table zones. shrug

What kind of CFM are you running during cutting, anyway?
Why do you need so much?


I'm glad I didn't pipe it first, then find out!

That might have been interesting, wot? g


--
A sound mind in a sound body is a short but full description
of a happy state in this world.
-- John Locke

On 2/16/2015 12:35 PM, Gunner Asch wrote:
On Sun, 15 Feb 2015 21:38:49 -0600, Martin Eastburn
wrote:

On 2/15/2015 5:44 PM, Gunner Asch wrote:
On Sun, 15 Feb 2015 16:18:07 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tim Wescott fired this volley in news:cb-
:

Lloyd, 2" + 2" = 4". What's your problem?

Yeah...that's what they thought, too!
Lloyd

Btw..if anyone needs vacuum pumps/gear

http://www.ebay.com/itm/Used-Edwards...-/131428338951

He has a number of pumps including one thats absolutely brand new..NOS

http://www.ebay.com/itm/New-Unused-E...-/131428334706

There are several others..keep watching if the above is not what you
need..or simply call him

Gunner


What kills me is there isn't a mention of what level of vacuum it can pull.

Is this a food grade bag sucker ?
Is this a 4'x16' plastic vac table for CNC plastic.....

One has to know the machine and use before spending 1 or 2.5k !

Martin

I believe that the model number will tell you , wont it?

They came out of GE Aviation

This might tell you something....

http://www.pchemlabs.com/product.asp?pid=1398

http://mfc.engr.arizona.edu/document...%20Install.pdf

I see that a rebuilt one goes for $9k

Google is your friend...usually ....

Gunner

I was naturally asking why the seller didn't mention anything about use or
actual ability.

Coming out of GE Aviation is such a wide boundary of possible uses.

The pchemlabs say specs and use. I had a 4 stage Hg that bubbled Hg
as it took down to make X-Ray tubes in research. This one wouldn't
be considered for that use.

Martin

On Mon, 16 Feb 2015 21:24:06 -0600, Martin Eastburn
wrote:

On 2/16/2015 12:35 PM, Gunner Asch wrote:
On Sun, 15 Feb 2015 21:38:49 -0600, Martin Eastburn
wrote:

On 2/15/2015 5:44 PM, Gunner Asch wrote:
On Sun, 15 Feb 2015 16:18:07 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tim Wescott fired this volley in news:cb-
:

Lloyd, 2" + 2" = 4". What's your problem?

Yeah...that's what they thought, too!
Lloyd

Btw..if anyone needs vacuum pumps/gear

http://www.ebay.com/itm/Used-Edwards...-/131428338951

He has a number of pumps including one thats absolutely brand new..NOS

http://www.ebay.com/itm/New-Unused-E...-/131428334706

There are several others..keep watching if the above is not what you
need..or simply call him

Gunner


What kills me is there isn't a mention of what level of vacuum it can pull.

Is this a food grade bag sucker ?
Is this a 4'x16' plastic vac table for CNC plastic.....

One has to know the machine and use before spending 1 or 2.5k !

Martin

I believe that the model number will tell you , wont it?

They came out of GE Aviation

This might tell you something....

http://www.pchemlabs.com/product.asp?pid=1398

http://mfc.engr.arizona.edu/document...%20Install.pdf

I see that a rebuilt one goes for $9k

Google is your friend...usually ....

Gunner

I was naturally asking why the seller didn't mention anything about use or
actual ability.

Coming out of GE Aviation is such a wide boundary of possible uses.

Ayup!!

The pchemlabs say specs and use. I had a 4 stage Hg that bubbled Hg
as it took down to make X-Ray tubes in research. This one wouldn't
be considered for that use.

Martin

He didnt mention the use or capabilities..because he picked them up at
an auction and is simply rolling them over for cash. He is a dealer,
not an end user. Its up to the prospective buyer to figure out if its
something he can use or not. Shrug

He has several others that neither he nor I can figure out what they
are used for. Ill bring up a link as soon as he puts them up on Ebay.

They have German test equipment bolted to them along with another type
of pump PLUS a vac system



"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

On Mon, 16 Feb 2015 20:14:22 -0800, Gunner Asch
wrote:

On Mon, 16 Feb 2015 21:24:06 -0600, Martin Eastburn
wrote:

On 2/16/2015 12:35 PM, Gunner Asch wrote:
On Sun, 15 Feb 2015 21:38:49 -0600, Martin Eastburn
wrote:

On 2/15/2015 5:44 PM, Gunner Asch wrote:
On Sun, 15 Feb 2015 16:18:07 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tim Wescott fired this volley in news:cb-
:

Lloyd, 2" + 2" = 4". What's your problem?

Yeah...that's what they thought, too!
Lloyd

Btw..if anyone needs vacuum pumps/gear

http://www.ebay.com/itm/Used-Edwards...-/131428338951

He has a number of pumps including one thats absolutely brand new..NOS

http://www.ebay.com/itm/New-Unused-E...-/131428334706

There are several others..keep watching if the above is not what you
need..or simply call him

Gunner


What kills me is there isn't a mention of what level of vacuum it can pull.

Is this a food grade bag sucker ?
Is this a 4'x16' plastic vac table for CNC plastic.....

One has to know the machine and use before spending 1 or 2.5k !

Martin

I believe that the model number will tell you , wont it?

They came out of GE Aviation

This might tell you something....

http://www.pchemlabs.com/product.asp?pid=1398

http://mfc.engr.arizona.edu/document...%20Install.pdf

I see that a rebuilt one goes for $9k

Google is your friend...usually ....

Gunner

I was naturally asking why the seller didn't mention anything about use or
actual ability.

Coming out of GE Aviation is such a wide boundary of possible uses.

Ayup!!

The pchemlabs say specs and use. I had a 4 stage Hg that bubbled Hg
as it took down to make X-Ray tubes in research. This one wouldn't
be considered for that use.

Martin

He didnt mention the use or capabilities..because he picked them up at
an auction and is simply rolling them over for cash. He is a dealer,
not an end user. Its up to the prospective buyer to figure out if its
something he can use or not. Shrug

He has several others that neither he nor I can figure out what they
are used for. Ill bring up a link as soon as he puts them up on Ebay.

They have German test equipment bolted to them along with another type
of pump PLUS a vac system

Btw....anyone need a load cell?

http://www.ebay.com/itm/Huge-91-Lb-2...-/371260378935


"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

On Mon, 16 Feb 2015 19:09:01 -0600, Tim Wescott
wrote:

On Mon, 16 Feb 2015 19:37:10 +0000, David Billington wrote:

Another electronics graduate mentioned
that he wasn't aware that capacitors came in varying ESR grades until he
looked into why some circuits weren't performing as expected, maybe he
hadn't been paying attention in class.

That's definitely not something you learn in class -- you get that after
you're fending for yourself in industry.

A good engineering education should teach you the basics, and how to learn
anything on top of that, but cannot, of necessity, do much of the "on top
of that", because it takes decades.

I found that the Dean of Coleman College (now University) was right.
What they taught there was simply the _language_ of electronics and I
had to learn a whole lot more to become any good. Unfortunately, I
changed careers once again after only 3 years (corporate takeover and
I bailed with small parachute), so my electronics technician training
quickly disappeared before I became fully competent and comfortable in
the field. I didn't get much past 2nd Louie myself.

--
A sound mind in a sound body is a short but full description
of a happy state in this world.
-- John Locke

Larry Jaques fired this volley in
:

What kind of CFM are you running during cutting, anyway?
Why do you need so much?

Larry, a large table like that, running porous work like particle board
parts, might simply 'leak' a couple of hundred cfm. And that's with 'best
effort' at taping edges, covering up recent cut lines, etc.

A LOT of air sneaks through paths not intended. That's why there's a 20HP
FPZ regenerative blower on 'just' a 4x8 table.

LLoyd

On Tue, 17 Feb 2015 05:57:44 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
:

What kind of CFM are you running during cutting, anyway?
Why do you need so much?

Larry, a large table like that, running porous work like particle board
parts, might simply 'leak' a couple of hundred cfm. And that's with 'best
effort' at taping edges, covering up recent cut lines, etc.

A LOT of air sneaks through paths not intended. That's why there's a 20HP
FPZ regenerative blower on 'just' a 4x8 table.

Thanks. I hadn't known just how leaky they were.

--
A sound mind in a sound body is a short but full description
of a happy state in this world.
-- John Locke

On 2/16/2015 10:14 PM, Gunner Asch wrote:
On Mon, 16 Feb 2015 21:24:06 -0600, Martin Eastburn
wrote:

On 2/16/2015 12:35 PM, Gunner Asch wrote:
On Sun, 15 Feb 2015 21:38:49 -0600, Martin Eastburn
wrote:

On 2/15/2015 5:44 PM, Gunner Asch wrote:
On Sun, 15 Feb 2015 16:18:07 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tim Wescott fired this volley in news:cb-
:

Lloyd, 2" + 2" = 4". What's your problem?

Yeah...that's what they thought, too!
Lloyd

Btw..if anyone needs vacuum pumps/gear

http://www.ebay.com/itm/Used-Edwards...-/131428338951

He has a number of pumps including one thats absolutely brand new..NOS

http://www.ebay.com/itm/New-Unused-E...-/131428334706

There are several others..keep watching if the above is not what you
need..or simply call him

Gunner


What kills me is there isn't a mention of what level of vacuum it can pull.

Is this a food grade bag sucker ?
Is this a 4'x16' plastic vac table for CNC plastic.....

One has to know the machine and use before spending 1 or 2.5k !

Martin

I believe that the model number will tell you , wont it?

They came out of GE Aviation

This might tell you something....

http://www.pchemlabs.com/product.asp?pid=1398

http://mfc.engr.arizona.edu/document...%20Install.pdf

I see that a rebuilt one goes for $9k

Google is your friend...usually ....

Gunner

I was naturally asking why the seller didn't mention anything about use or
actual ability.

Coming out of GE Aviation is such a wide boundary of possible uses.

Ayup!!

The pchemlabs say specs and use. I had a 4 stage Hg that bubbled Hg
as it took down to make X-Ray tubes in research. This one wouldn't
be considered for that use.

Martin

He didnt mention the use or capabilities..because he picked them up at
an auction and is simply rolling them over for cash. He is a dealer,
not an end user. Its up to the prospective buyer to figure out if its
something he can use or not. Shrug

He has several others that neither he nor I can figure out what they
are used for. Ill bring up a link as soon as he puts them up on Ebay.

They have German test equipment bolted to them along with another type
of pump PLUS a vac system



"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

Might be from a thin film or thick film module group.
e.g. think voltage regulator inside of the alternator in the car/truck.
That white plastic thing...

Martin