I hadn't given this much thought, but there are several companies (including the one that I work for) that make tone generators and inductive probes which may be used to trace telephone wires. Most probes are sensitive enough that they even allow the line to be traced through walls. Many also have a lower sensitivity level so that you can make sure you've identified the correct pair among a group of wires. I don't know how well the pipes will carry the tones, or if they are subject to cross-talk (the tone from one pipe is picked up on another pipe), but the idea of using a tone and probe might merit some investigation. Our tone generator and probe are listed at the bottom of this web page: http://www.commprod.harris.com/testsets-tools/tools/tools1.html There are several others made by various companies and you can generally mix and match tone generators and probes. In fact, you can probably make a tone generator on your own with little difficulty. The probe is the tricky thing to make. -Mike -----Original Message----- From: Bob Bullock [mailto:bobb@prostyle.com] Sent: Monday, January 15, 2001 11:20 AM To: PICLIST@mitvma.mit.edu Subject: Re: [EE]: A tough design challange - how to trace metal pipes 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: >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. > > bobb@prostyle.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 listserv@mitvma.mit.edu with SET PICList DIGEST in the body > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! >email listserv@mitvma.mit.edu with SET PICList DIGEST in the body Bob Bullock President Western Support Group Ltd. bobb@prostyle.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 listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body