wasilko@ames.arc.nasa.gov (Jeff Wasilko) (08/07/89)
I've seen compressed gas cylynders near poles and I've always wondered what purpose they are used for? Could anyone shed some light on this? Thanks Jeff Wasilko
silber@tcgould.tn.cornell.edu (Jeffrey Silber) (08/08/89)
In article <telecom-v09i0278m05@vector.dallas.tx.us> Jeff Wasilko <claris!apple !netcom!wasilko> writes: >I've seen compressed gas cylynders near poles and I've always wondered what >purpose they are used for? Could anyone shed some light on this? Major phone trunks are pressurized, to prevent moisture in the cables. The pressurization is done at the CO. I've always assumed that where they have had to cut a trunk to repair it they put the tanks (nitrogen, I believe) in place to provide temporary pressurization. -- "A billion here, a billion there, and pretty soon you're talking real money." --Sen. Everett Dirksen Jeffrey A. Silber/silber@tcgould.tn.cornell.edu Business Manager/Cornell Center for Theory & Simulation in Science & Engineering
RS%AI.AI.MIT.EDU@mintaka.lcs.mit.edu (Robert E. Seastrom) (08/08/89)
These tanks are probably dry nitrogen, for pressurizing hardline
(ie air-insulated) coax.
---Robjohn@apple.com (John Higdon) (08/08/89)
In article <telecom-v09i0278m05@vector.dallas.tx.us>, claris!apple!netcom! wasilko (Jeff Wasilko) writes: > I've seen compressed gas cylynders near poles and I've always wondered what > purpose they are used for? Could anyone shed some light on this? These tanks are filled with nitrogen. By using positive pressure withing the cable housing, moisture is kept out and sudden loss of pressure could indicate cable damage or failure. BOCs generally pressurize from central points; GTE and other independents use those tanks that you have noticed. -- John Higdon | P. O. Box 7648 | +1 408 723 1395 john@zygot.uucp | San Jose, CA 95150 | M o o !
onymouse@ames.arc.nasa.gov (John DeBert) (08/10/89)
In article <telecom-v09i0278m05@vector.dallas.tx.us>, claris!apple!netcom! wasilko (Jeff Wasilko) says: > I've seen compressed gas cylynders near poles and I've always wondered what > purpose they are used for? Could anyone shed some light on this? I have seen them too. To satisfy my curiousity, I examined one closely. It appears to be either nitrogen or compressed dry air attached via a pressure regulator to a fitting on a cable or splice cover. The prupose appears to be to force out water and moisture to prevent corrosion. A yellow cylinder contains compressed air and one that is silver with green at the top is nitrogen gas. Once or twice, I have seen helium cylinders (silver with orange) in place, perhaps because nothing else was available(?) Compressors can also be found, especially in remote areas, used also to keep cables and connections dry. JJD onymouse@netcom.UUCP
gt0818a%prism@gatech.edu (Paul E. Robichaux) (08/10/89)
Around my neighborhood, there are several telephone poles which commonly have gas containers chained to them. My understanding is that local welders can leave the tanks there and have a service company (say, Union Carbide/Linde) come by, get them, fill them with non-flammables, and put them back. Don't know if this is true- I heard this from my next-door neighbor the welder. -Paul -- Paul E. Robichaux | REMEMBER the HOSTAGES!! Georgia Institute of Technology | (and don't let that SOB Obeid go, either) GT PO Box 30818; Atlanta, GA 30332 |============================================ Internet: gt0818a@prism.gatech.edu | All opinions in this message are mine.
onymouse@ames.arc.nasa.gov (John DeBert) (08/11/89)
in article <telecom-v09i0285m10@vector.dallas.tx.us>, I said: > > A yellow cylinder contains compressed air and one that is silver with green > at the top is nitrogen gas. Once or twice, I have seen helium cylinders > (silver with orange) in place, perhaps because nothing else was available(?) > I wasn't sure if nitrogen cylinders also used green as green usually marks oxygen cylinders. Yesterday, while at work, I checked. nitrogen cylinders have beige paint on them, not green. I doubt that any telco would seriously consider pressurising a cable with oxygen... JJD onymouse@netcom.UUCP
mhw@wittsend.lbp.harris.com (Michael H. Warfield (Mike)) (08/12/89)
In article <telecom-v09i0287m09@vector.dallas.tx.us> claris!apple!netcom! onymouse@ames.arc.nasa.gov (John DeBert) writes: >in article <telecom-v09i0285m10@vector.dallas.tx.us>, I said: >> A yellow cylinder contains compressed air and one that is silver with green >> at the top is nitrogen gas. Once or twice, I have seen helium cylinders >> (silver with orange) in place, perhaps because nothing else was available(?) >I wasn't sure if nitrogen cylinders also used green as green usually >marks oxygen cylinders. Yesterday, while at work, I checked. nitrogen >cylinders have beige paint on them, not green. While there are certain standards for tank markings, outside of some well establish colors there seems to be some variation when it comes to less dangerous or critical gasses. From my days in the broadcast industry I believe the dry nitrogen we used to pressurize our lines came in silver tanks with an orange top. Most of the time that is. There were exceptions (some solid silver tanks and I think I remember a shipment with blue tops). However, I do believe that SOLID green is reserved for MEDICAL oxygen while oxygen for welding is in solid orange cylinders. I have also seen tanks which had a colored band while the tops and bottoms were the same color (generally silver for those). I would seriously doubt anyone would pressurize a line with helium. The cost would be prohibitive and helium would bleed out of the line over time (helium is notorious for bleeding right through metal). Best source of finding out what's what would be to check in an AIRCO (welding gas supplier) catalog (used to have one around this joint somewhere :->) or another local welding supplier. --- Michael H. Warfield (The Mad Wizard) | gatech.edu!galbp!wittsend!mhw (404) 270-2123 / 270-2098 | mhw@wittsend.LBP.HARRIS.COM An optimist believes we live in the best of all possible worlds. A pessimist is sure of it!