Searching \ for '[EE]: A tough design challange - how to trace meta' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=tough+design+challange
Search entire site for: 'A tough design challange - how to trace meta'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: A tough design challange - how to trace meta'
2001\01\15@014938 by Bob Bullock

flavicon
face
Hello all,

A friend of mine's father has a company that installs and maintains systems
for delivering lubricating oil to large roller equipment such as in a paper
mill.  There can be hundreds of 1-1/4 inch metal pipes running out to
bearings to deliver lubricating oil under pressure.  These pipes are
sourced from a large bank of valves that are used to set the flow
rates.  Many of these sites are several years old and what ever method
(usually tags) that was used to mark the pipes as to where each one runs
too, has long since disappeared.  He as asked me to build him something
that can be used to trace the pipes.  When they do some sort of
upgrade/maintenance they need to trace all of the pipes to the end
bearings.  Currently, it can take a team of two people weeks to do this.

The ideal method would involve attaching some form of signal generator to
the pipe of interest, at the bearing end, and to use some form of detector
at the end where all of the pipes meet and detect which pipe is the run
that goes to the bearing with the generator on it.

Some key limitations.  The pipes can not be brought out of use so there is
no way to introduce anything into the pipe, or to insert anything internal
to the pipe, it must all be done from the outside.  At several points near
the end where all of the pipes meet, there are pipe clamps that
electrically connect/short all of the pipes together.

The pipes all end up connected to a common metal block.

My thoughts have been along the line of possibly using sound.  If an
ultrasonic signal was somehow injected into the pipe, maybe it could be
detected at the other end.  Some energy would get reflected back into the
adjacent pipes but should be at an attenuated level than the source
pipe.  Also, if you were sending pulses,  there would be a phase change
from the incident wave and the reflected waves. The pipes with reflected
waves would all tend to be the same with the pipe with the incident wave
standing out.

Maybe these concepts would work with microwave signals as well.

Anyway, its a stumper to me, but I have always been amazed at the creative
ways to apply electrons devised on this list.  Naturally, I would want to
use a PIC somewhere in it.

Bob Bullock
President
Western Support Group Ltd.
spam_OUTbobbTakeThisOuTspamprostyle.com
Certified Microchip Consultants
http://www.microchip.com/10/Consult/Country/Canada/index6.htm#915-277

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email .....listservKILLspamspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@033623 by Jinx

face picon face
Is it possible to introduce a small amount of dye into a pipe ?

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listservspamKILLspammitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@034702 by Jinx

face picon face
Beg pardon - missed the point about not being able to introduce
anything. Thought you may have been able to get access to the
fluid for even a very short time

Why don't you try an audio test and see how it goes. You might get
lucky or it could be back to basics and just trace them manually.
With them all connected together like that you'd have to have a
pretty good result to be confident that it would work over the whole
system

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email .....listservKILLspamspam.....mitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@053906 by Quentin

flavicon
face
I have seen these lubrication pipes you are talking about. The
sound/ultrasonic/microwave idea sounds good. A few problems come to mind
(not that I have tried this, just musing here):
Since the pipes have oil in it already, how much would that dampen the
signal?
All these pipes are mounted to the frame of the machine and are also
normally run in a bundle together before they split up. How much of the
signal will resonate through the the frame or give you false readings in
other pipes?

I would use a pressure switch on the one end and pressuring the other
ends at the distributor with oil individually until you get a reading.
OK, You want to use a PIC.
How about have a couple of  P-switches into the PIC and a readout?
Even better, these kind of machines are long and big and consist of
different units: a couple of slave units with P-switches, serially
connected to a master with a display (opportunity for lot's of PIC's
here, hehe).

Quentin

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email EraseMElistservspam_OUTspamTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@062226 by Russell McMahon

picon face
>A friend of mine's father has a company that installs and maintains systems
>for delivering lubricating oil to large roller equipment such as in a paper
>mill.  There can be hundreds of 1-1/4 inch metal pipes running out to
>bearings to deliver lubricating oil under pressure.  These pipes are
>sourced from a large bank of valves that are used to set the flow
>rates.



May be you have to go to the mountain ... :-)

1.    While the pipes are electrically connected at the commoned end they
MAY not have earthing further out.
Also, if there is earthing at the far end as well but not in between this
may also work.
Injecting a signal at some point in the pipe relative to ground may allow
detection of current flow at the source.
Injected signal needs to be large enough to be detectable and small enough
to not be hazardous to people or equipment - eg you don't want to risk
pitting bearings which current may flow through. You could establish if this
was liable to happen.

A variable current source would probably deliver several amps at very low
voltage as the pipes are metal and presumably of reasonable conductivity.
Some forms of jointing may make this a bad assumption.

- If pipes are only grounded at source end then the procedures below can be
simplified greatly.
- If pipes are grounded occasionally at various points the following method
still MAY work.
- If pipes are consistently grounded multiple times in their run then the
following method probably won't work.

If both ends are earthed but the middle isn't, injecting current some way
along the pipe's run relative to the common point (preferably half way)
would lead to say 100 units of current in the target pipe but much lower
return currents in the other pipes

Remote ends
|
\/
|----------------------------------------------|
|----------------------------------------------|
|----------------------------------------------|
|----------------------------------------------|
|xxxxxxxxxxx P yyyyyyyyyyyyyyyyyyy|  Common
|----------------------------------------------|
|----------------------------------------------|
|----------------------------------------------|
|----------------------------------------------|
|----------------------------------------------|

Using a nasty flying lead current is injected into pipe xxxxxxxxxpyyyyyyyyy
at point P.
Other side of current source is connected to common end.

Current flows from P back towards common end AND also from P towards remote
end IF remote ends grounded.
Once current gets to remote end it will divide and return to common point
via ALL other N pipes.
If current from P to remote end is I then return current in all other pipes
will be I / (N-1) on average for N pipes.

Placing  a differential voltage detector at the remote end of a pipe will
show a current flow TOWARDS the remote end for the target pipe and AWAY from
it for other pipes. The detector could be not too much more than a simple
comparator or very high gain amplifier connected to the remote point and
another point a small distance up the pipe towards the source.

If a suitably large current is used (probably not too large - say under 10
amps), then the distance from the common point to point P may be able to be
a small fraction of the total pipe length - possibly just a few metres.
The procedure would then be -
- Place detector at far end of target pipe compete with helper with 2 way
radio.
- Apply current to each pipe in turn a few metres away from common point.
- For each non-target pipe, helper should see detector kick in the
return-pipe direction.
 For the target pipe the detector would kick in the opposite direction.

For a 1/4" OD pipe with 1/16" walls the pipe is 3/4 solid.
For 1/32" walls it is still about 30% solid.

Without working it out I would guess that pipe resistances are in the order
of 10's to 100's of ohms per run depending on material etc.
If you are unlucky they may have used joints which are non conductive.

On a 100m run if you use enough current to produce 10 volts drop then a 1
meter length will drop around 0.1 volt.
A differential detector will measure millivolts with ease and microvolts
with suitable care and design so it may well be possible and maybe almost
easy :-).


2.    Acoustic injection seems like a nice idea if you can manage it.
Just maybe modulating the valve handle (depending on valve design) with a
capable acoustic driver may introduce enough modulation to the flow to
produce a detectable signal. eg a powerful speaker driver may suffice -
probably 50 watts or more - the more the better but the valve may need
substantial travel at the acoustic frequency to achieve modulation which
would probably not be feasible.

3.    Acoustic pulse applied externally - possible by mechanical striking or
electronic transducer doing same.
Possibly a burst of height energy acoustic signal as a pulse from eg a sonar
transducer.
A high powered ultrasonic cleaning head may have what it takes.

Acoustic detector for above schemes would vary with method used.


regards,




     Russell McMahon
_____________________________

What can one man* do?
Donate food daily free !!! -  http://www.thehungersite.com/
Donate Vitamin A!  http://www.thechildsurvivalsite.com/
http://www.rawa.com  - one perspective on Afghanistan
http://www.changingourworld.com    http://www.easttimor.com   http://www.sudan.com

(* - or woman, child or internet enabled intelligent entity :-))

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listservspamspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@100554 by Bob Ammerman

picon face
I think some sort of acoustic (ultrasonic) technique has the best chance of
working.

I'd set up a 'pinger' at the bearing end.

At the other end I'd set up _two_ receivers.

I'd use a display that shows the relative time that the 'ping' gets to the
receivers.

Now you touch the two receiver probes to the mess of pipes at the valve/tank
end. You can tell which probe is closer to the 'pinger'. Now it is just a
version of the children's game hot/cold to find the incoming pipe (it will
be the only one where a probe 2' from the valve bank gets the signal before
a probe 1' from the valve bank does.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

{Original Message removed}

2001\01\15@102635 by Bob Ammerman

picon face
Another thought was brought on by the response below.

When pipes are run together in a group the 'ping' would tend to couple to
the other pipes in the group and propogate in the same direction. This would
fool a time-based differential probe system. Therefore, I think you'll also
need to do an amplitude comparison between the two probes so that you could
differentiate by either amplitude or timing.

With a little experience, I imagine this would be a useful tool to greatly
aid manual tracing of the pipes. I don't expect it would work too well
across the entire length of the plant, though.

I am envisioning a couple of probes connected to a small box containing the
electronics (and PIC, of course). Colored LEDs on the probes could indicate
which one is seeing the stronger signal, as well as which one is seeing the
earlier signal.

You might even jam the electronics into the probe body (batteries in one
probe, rest of electronics in the other).


{Original Message removed}

2001\01\15@104122 by Maris

picon face
Possibly you could wrap pipe heaters around a section of the pipe at the
beginning and look for a temperature increase at the other end of the pipe.

The oil would lose most of its heat as it travelled, but there might be a
temperature increased of a degree or so at the end if the oil was heated
enough at the beginning.

This could be detected with a thermistor in a Wheatsone bridge, amplified
by an opamp and fed to a PIC ADC input (what else?). Even a fraction of a
degree temperature increase could easily be detected.

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email @spam@listservKILLspamspammitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@104329 by Roman Black

flavicon
face
Bob Ammerman wrote:
>
> Another thought was brought on by the response below.
>
> When pipes are run together in a group the 'ping' would tend to couple to
> the other pipes in the group and propogate in the same direction. This would
> fool a time-based differential probe system. Therefore, I think you'll also
> need to do an amplitude comparison between the two probes so that you could
> differentiate by either amplitude or timing.
>
> With a little experience, I imagine this would be a useful tool to greatly
> aid manual tracing of the pipes. I don't expect it would work too well
> across the entire length of the plant, though.

I think i'd try connecting a low-ish freq ac
(like 400Hz) to the far end of the pipe, and test
with a magnetic pickup (like the phone ones at
radio shack) waving it near all the pipes at the
end where they all come together. Telecom companies
use a similar system with long wires, it works
pretty well. Even if the pipes are joined in
places by the clamps, they are unlikely to have
as strong a signal as the "one" pipe.
A small ac coupled amp and a mV meter would
give a good indication, with an audio tone as
well. I have one of the telecom type tracers,
it's very simple.
-Roman

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email KILLspamlistservKILLspamspammitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@105338 by Olin Lathrop

face picon face
> He as asked me to build him something
> that can be used to trace the pipes.

How about sound pulses instead of steady waves, then measure the delay from
emitter to various locations to get some idea of pipe distance.  Reflections
from the main manifold should come later than the original ping.  This might
not work perfectly, but would hopefully cut down the number of cases that
require manual tracing.


*****************************************************************
Olin Lathrop, embedded systems consultant in Devens Massachusetts
(978) 772-3129, RemoveMEolinTakeThisOuTspamembedinc.com, http://www.embedinc.com

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email spamBeGonelistservspamBeGonespammitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@111414 by William Jacobs

flavicon
face
Bob:
       What kind of pressure is involved in the lube oil?  Could you cycle the
flow valve and measure a distortion in the pipe at the bearing?
       What kind of flow is involved in the lube oil?  Could you actually hear
the oil flow with a high gain amp?
Bill Jacobs

Bob Bullock wrote:
{Quote hidden}

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listservEraseMEspam.....mitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@113951 by jamesnewton

face picon face
Add a small piston or diaphragm to the source of each pipe and a fast acting
pressure gauge at the other end. Oscillate the piston or diaphragm and see
which gauge is fluctuating.

---
James Newton (PICList Admin #3)
EraseMEjamesnewtonspampiclist.com 1-619-652-0593
PIC/PICList FAQ: http://www.piclist.com or .org

{Original Message removed}

2001\01\15@115129 by Quentin

flavicon
face
OK, since we are talking machines here, I'll throw a few more spanners
in the works. :)
I've seen quite a few of these lubricating systems over the years (paper
mills, paper converters and printing presses).

Let me share what I have seen because I am also interested with what you
guys can come up with:

They almost always use metal pipes (brass, copper, aluminum, steel or
stainless) for these lines. Occasionally they use plastic or rubber
pipes but these are mostly for a direct flexible connection to moving
parts.
These pipes are clamped with metal clamps to the frame of the machine,
at various places all over the machine (vibration).
The machines are always connected to ground (besides for obvious
reasons, paper also generate a lot of static).
So you got a lot of ground connections at various places all along the
pipes on machines that could be the length of a football field. Most
machines consists of units and each unit has its own central lubrication
system, but even one of these units are huge with a lot of pipes (think
arteries here and you'll get the picture).

And as I have said, I am still concerned about what the oil in the pipes
would do to the signals.

So my question still is: How are you going to send an acoustic signal,
ping or pulse through all that?

Quentin
PS: My experience with this list is that engineers here love a
challenge, anybody remember the chicken counting posts? :)

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email RemoveMElistservEraseMEspamEraseMEmitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@115749 by Bob Ammerman

picon face
If we could come up with some kind of signal that propagated well in the
oil, but not through the metal, that would be a lot of help.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

{Original Message removed}

2001\01\15@123742 by KD7TS

flavicon
face
Maybe it would be possible to couple an excitation field into a pipe and vary
the drive frequency to find the mechanical resonance.(The pipe expands and
contracts alternately in length and width, like wind chimes). Cross coupling
should be minimal to other pipes and will be peak only on one pipe.Detection
might be done through amplitude detection. Could also cause joints to begin
leaking !

This system is used with sheet pile drivers to cause the pilings to sink,
without hammering.

A hammer and stethoscope might work just as well, as the pipe will "ring" when
struck, but wouldn't necessarily need a PIC. Interesting discussion...


Mike R

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email RemoveMElistservspam_OUTspamKILLspammitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@134607 by mike

flavicon
face
A few thoughts : if the pipes are copper, you could probably get a very signifcant
local heating effect using  induction to directly heat the copper, and
detect a heat 'pulse' of the heated oil with a sensor further down the
line - detecting a relatively fast but very small temp rise should not
be too difficult - it may not  work on the whole  pipe run but might
be do-able in sections, and would depend on the oil flowrate
How about using RF - a long pipe run will have significant inductance,
so the effects of periodic grounding could be greatly reduced, and you
could probably trace from clamp to clamp pretty easily. Maybe you
could loosen the clamps during testing to reduce attenuation?

A high current impulse might also be worth a try, e.g. a capacitive
discharge, so you could use very high currents (hundreds of amps), but
the short time would avoid heating. Some this current would make it
through the probably less-than-perfect electrical contact at the
clamps and be detectable via magnetic field and/or voltage drop along
the pipe. Imagine passing, say  a 100 amp discharge  from the bearing end of the
pipe to the common  block, and sensing the voltage across a foot or
two of pipe at the block, or across the pipe-to-block couplings - you
could fairly easily detect a few microvolts, so I would imagine this
might work.

{Quote hidden}

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email RemoveMElistservKILLspamspammitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@140716 by Bob Bullock

flavicon
face
Bill,

Good question.  At the moment I don't know the answer.  I am going to
schedule a tour through a plant so I have a better understanding of the
environment.  The post from Quentin is a pretty accurate description of the
installation as I understand it.  Each pipe running to a bearing has a
specific flow rate set up for it and different bearings have different flow
rates.  There would of course be many with the same flow rate.

Lots of good ideas to pursue so far.  The key to the ideal solution of
course is that the traced signal is injected at the bearing end of the pipe
and gets identified among the maze of pipes at the source.

Regards,

At 1/15/2001 08:04 AM, you wrote:
{Quote hidden}

Bob Bullock
President
Western Support Group Ltd.
EraseMEbobbspamEraseMEprostyle.com
Certified Microchip Consultants
http://www.microchip.com/10/Consult/Country/Canada/index6.htm#915-277

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email @spam@listserv@spam@spamspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body


2001\01\15@154037 by Oliver Broad

flavicon
face
How about using magnetic devices as tracing transducers. Injecting AC
somewhere and following it with a curent clamp that was phase sensitive
would distinguish one pipe from another. If grounded at both ends then maybe
you need another clamp as signal injector. The key aspect is that if you
launch the trace signal magnetically the short circuit at the end works in
your favor, not against you.

Oliver.

{Original Message removed}

2001\01\16@164336 by Peter L. Peres

picon face
This is not a solution ;-)

Why would anyone use tags on an oil pipe and hope for the tags to remain
there for years (one uses poinsons to press letters and symbols into the
soft-walled pipes with a small hammer. This lasts over 300 years,
guaranteed). Next, one draws a schematic of what was done and places
copies thereof in suitable places.

If none of this was done then I think that injecting current into the
pipes (as far as possible from both ends, or at least as far as possible
from the machine end) will likely cause an unnoticeable current vs. the
existing ground currents and noise. Injecting a fairly high powered single
frequency signal (probably as high as 1-2MHz) and looking for it with
narrowband probes may have a fighting chance imho.

If I'd do this I'd set up a test oscillator with AM30% 2kHz and carrier
somewhere in the AM band (unused frequency) and couple it directly into
the pipe vs. ground at the machine, and go hunting with a small AM radio
tuned to it along the pipes. The generator should output 0.5 to 10W or so.

I know that someone is upset because of the 'illegal' broadcast in the
AM band. Rest assured that the plant around you already fills that
frequency with much more than your 10W, and probably the whole rest of the
spectrum too, for several miles around, and up (and down). At least the AM
radio has a 0.5-2% bandwidth and this should put the noise down 20dB or
more vs. dc only with the same power. If a second filter is used on the
2kHz then even more noise attenuation is possible. Even so getting a
decent reading is going to be interesting, if the plants are as I think
they are, i.e. not designed with ground current and EMI/RFI suppression in
mind.

I have always likened using sensitive (RF) devices in an industrial plant
to doing DX on the AM broadcast band in the middle of a thunderstorm,
while standing under a 110kV HV power line ;-)

good luck,

Peter

--
http://www.piclist.com hint: To leave the PICList
spamBeGonepiclist-unsubscribe-requestspamKILLspammitvma.mit.edu


2001\01\17@015024 by Scott Stephens

picon face
Sound travels very well in solids. You could have someone (something) tap
the bearing end with a hammer and listen with a stethescope (or spike mike)
at the valve end, unless there are air bubbles. An air bubble would act like
a resonant cavity, in effect tunning the oil pipe, which could identify
pipes also.

Scott

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...