Post by thread:[EE]: A tough design challange

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_OUTbobbTakeThisOuTprostyle.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 .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

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_OUTTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

>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? 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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 KILLspamlistservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

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

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 RemoveMElistservEraseMEEraseMEmitvma.mit.edu with SET PICList DIGEST in the body

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}>Bob Bullock wrote: >> >> 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. >> RemoveMEbobbTakeThisOuTspamprostyle.com >> Certified Microchip Consultants >> www.microchip.com/10/Consult/Country/Canada/index6.htm#915-277 >> >> -- >> http://www.piclist.com#nomail Going offline? Don't AutoReply us! >> email EraseMElistservspamspamBeGonemitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

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: > 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: > > > > 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. > > bobbSTOPspamspam_OUTprostyle.com > > Certified Microchip Consultants > > www.microchip.com/10/Consult/Country/Canada/index6.htm#915-277 > > > > -- > > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > > email spamBeGonelistservSTOPspamEraseMEmitvma.mit.edu with SET PICList DIGEST in the body > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! >email KILLspamlistservspamBeGonemitvma.mit.edu with SET PICList DIGEST in the body Bob Bullock President Western Support Group Ltd. EraseMEbobbEraseMEprostyle.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@spam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

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-requestKILLspammitvma.mit.edu