Document gbve0mGBBQx7Bm5wDMj18VE5N

ep your lose handy.,, leepHSAFE! man mm seels. BACKTALK Lsttare of interest from readers--for n Misting Actuator Just finished reading "Powered Valve Actuators" (PE 12/24/75, p. 34). It was vary interesting and moat informative. We were disappointed, however, that our client, Jordan Con trols, Inc., of Milwaukee, was not included in your list of actuator sup pliers. Jordan manufactures and dis tributes a complete line of electric actuators, both rotary and linear. Mark McGUnchey, Vice President, Andrews Advertising Inc., Milwau kee, Wl. Using die listings in die Plant Enoineeunq Directory and Specifi cations Catalog is a base, sre make strenuous efforts to contact all the manufacturers who may be able to contribute information to a cover ar ticle. Jordan Controls is listed in the section on Instruments, Controls and Computers; but not under Piping, Valves, and Fittings--apparently an error on our part.--Editors PVC Plant Shutdowns In your "Briefing the News" sec tion [PE 1/8/76, p. 15/ you state: "Ibis is the first PVC plant to date to choose closing over meeting OSHA standards." The reference is to Uniroyal Chemical's Painetville, OH, facility. I think that if you will check the industry's records, you will find that when die standard was initially pub lished, the Olin Chemical PVC plant at Aasonet, MA, announced it was ending its operations; the reason was that it was not feasible to comply with the OSHA standard. The Good year Chemical plant at Niagara Falls, NY, also closed after the standard was made public. This was probably die second dosing. That would make Uniroyal die third. H. E. Jewett, Plant Manager, General Tire A Rub ber Co., Chemical/Plastics Div., Ash tabula, OH. We have checked with both the companies mentioned by Reader Jewett, and find that although the Otin Chemical plant at Aasonet dosed for other reasons, the Good year plant at Niagara Falls did in fact shut down beraiisr the cost of com plying with OSHA regulations could not he Justified. Thus, the Uniroyal pim at PainesviUe was the second such fhh| not the first, at we re ported. We stand corrected.--Editors Cmy Jones! Mounted to the Scale... The author is to be congratulated on the three-part article "Specifying Railroad Track Scales" (PE 10/16/ 75, p. 144; 12/11/75, p. 128; 1/22/ 76, p. 123). Our industry has long needed such a compendium, and he is to be commended for the research and effort put into this series. We would, however, take some issue with the imputation that "Scales employing load cells are slightly less accurate than mechanical types; ac curacies typically range fr m 0.03 to 0.06 percent when weighing coupled (The article quoted specified uncou pled cm. --Editors] cm." In-ser vice teats conducted by our company indicate that this is not necessarily the case. Electronic scales, for mo tion weighing, have built-in advan tages. In the end, they provide much more accurate weighing, as a rule. It it impossible to weigh a car when it is not fully scale-borne; it is impossible to weigh if the scale cannot balance and calibrate itself between weigh ings. Such problems are discovered in APRIL 15, 1976 Volume 30, No. 8 ity CUPFORD . HAMNAY * SON, MC. WMTSMJO; fCW YORK 12113 The Magazine for the Hunt Engineer America's industrial consumer - P S. A. SXjBO. r>< S26.0C. SWelr win SIM. ParaWm mbKilpncmj art rradrhU 34JO or for Du rpmtralm ol tx.00 VJ, At men Watt ftoym otrmcirt Sek w for aB mhtcrtptUmi muaUt V. 5. A. mA CaamU It /. S. Treuart, Ltd.. 1S4 A Gntaford Bead. Bmrow, Mlddtartx BAlSQT. Eariaed. No oibrcrtptUm ow It aatkaritad * u to roUctt or tWu ardari 1m mtocrtptkmt. Cheat* of addrto Sand m PLANT ENGINEERING, CtrtakOea DMaUrn, SarrtMt`<m. ItUeoti riaam^aujpt^ poattitm^tnu. cgafpeif mw, comem) eddraaa. ComeoBad ctmJattcm, pome* pWdor Wotoca. i SdOOS. PrMUhad Uwaaktp. 36 Item par ram. Todmical ftiMfcfcUf Coomb?, 1976-- AD Mthttlomrrod aTobcIOwSMpriSiriHinMamarCnodmtanednmT Circle 103 on Post Card 4 o SLANT ENGINEERING 0 APRIL 15. 1976 OLI 1136 Measure the value of Sperry Vickers by all we provide above and beyond a quality product Techniques for eliminating hydraulic leakage explained Costly, potentially hazardous leakage is not an inherent property of hydraulic systems* It can be eliminated by using good design and piping practice, and proper maintenance. In most cases, leakage occurs in hydraulic systems because of relatively minor factors which can easily be corrected. Correct sealing is one such factor. A radial lip seal, for example, prevents fluid leakage along a rotating shaft as long as a thin film of lubricant is maintained between the seal lip and rotating shaft. The seal lip must not act like a squeegee to wipe the shaft dry. The lip must ride on a thin film of lubricant to be suc cessful. If the film gets too thick, the seal leaks. If it gets too thin, the seal hardens or wears. Staling PtquirM an inter ference fit between shaft and flexible feeling lip. Bat e* feeU age and temperatom change, lip pmrara fall* oB. Consequently, a garter or finger spring is used to help maintain con stant pressure. Obstratiou courtesy of BattaUe Research. Specifying the correct seal elastomer and shaft surface finish is essential in preventing early seal failure and excessive leakage. Proper hose installation is a nearly-sure guarantee against premature hose failure and loss of system fluid. Allowing extra hose length protects metal parts from undue stress and avoids damage from kinks in the hose. Use of correct hose length and proper installation prevent early hose failure and resulting fluid lost. Illustration courtesy of Aaroqulp Cup- RIGHT i lift less prone to leak than systems with complex arrangements of hose and tub ing and hard-to-reach components. Each fitting and tube connection is a potential leak source; fewer connections mean fewer leaks. (Hard-to-reach com ponents leak more readily because proper assembly is difficult) Preferably, all valves should be backmounted on a readily-accessible plate with permanent pipe connections. Manifolding to eliminate external piping is even more effective. Threaded Joints: The main advantage with tapered threads is that a slight leak can usually be stopped by giving the connector an extra partial turn if the threads are perfectly machined and properly assembled. But often they're not, in which case no amount f tighten ing will correct a leak. Consequently, the present trend is the use of SAE straight threads which seal by means of an external element such as an O-ring. These are only a few of the many factors inv lved in correcting hydraulic leakage. For a complete explana tion of all the factors and their corrective methods, write for your copy of a valuable new 18-page book on the subject of con trolling hydraulic leakage, published by Sperry Vickers. To get your free copy, or for more information on Sperry Vickers families of hydraulic components, write Sperry Vickers, a division of Sperry Rand Corporation, Troy, Michigan 40084. R^V^VICKERS OLI 1137 Circle HZ m Post Card amiL IS, 1*76 a PLANT ENGINEERING 3