Analysis Interpretation Information
Cover Those Elbows Just as sweaters and coats wear out first at the elbows, so does insulation on pipe elbows —i.e., until the advent of jackets for ells ^ A L M O S T since the first use of insulated lines, maintenance engineers have faced the problem of abuse a n d d a m a g e to insulation. Some years ago, a l u m i n u m jackets to cover insulated .lines got a n enthusiastic reception, b u t ells were n o t included because of fabrication difficulties. If an ell was jacketed, it was a sitefabricated j o b — i n most cases, an expensive process. Because of attachment needs, jackets for ells m a d e u p of m a n y sections proved difficult, if not impractical, to remove and reinstall. T o cover ells, insulation material, plastic enough to apply over chicken wire a n d which hardened with time, came into wide use. This nonmetal jacketed elbow insulation invited abuse from passers-by. Often elbows project into areas which raise chances for t h e m t o b e accidentally b u m p e d with resultant damaged insulation. I n addition, vibration a n d shrinkage help make insulation on ells short-lived without protection. T w o southwestern fabricators of a l u m i n u m have come u p with economical a n d easy-to-install jackets to cover insulated ells. Both companies—Childers Manufacturing Co., Houston, Tex., a n d Preformed Metal Products Co. (Premetco), Shreveport, La.—developed twopiece a l u m i n u m jackets for ells. Precision m a d e , t h e jackets are available in sizes to fit several diameters of pipe, each of which m a y be covered with several different thicknesses of insulation. T h u s , for example, a l u m i n u m jackets to fit an 8-inch nominal size ell covered with insulation from 1 to 3 inches in 0.5-inch increments a r e n o w stock items. T h e jackets (see figure) a r e d e signed to fit snugly over a n insulated elbow and join smoothly with jackets
I/EC
covering straight lines. These companies say the jackets have a n internal moisture barrier applied a t the factory. According to Childers, their jackets can be installed with a l u m i n u m sheet metal screws. O n the other hand, Premetco recommends a special adhesive it m a n u factures, although they also say straps or screws can be used. First announced last year, alumin u m jackets for ells have received an even more enthusiastic welcome than straight aluminum jacketing did. " W h y m o t h e r necessity d i d n ' t bring us simple jackets for ells sooner," quips a n engineer, "could go down as one of t h e deeper mysteries of plant m a i n t e n a n c e . " B.F.G.
Isotopes Go Underground A d d another role for radioactive isotopes: underground petroleum tagging IVADIOISOTOPES
are
going
under-
ground—to boost oil production. Used as tracers, they help m a p t h e underground flow of fluids. T h e result: better knowledge of rock formations in oil a n d gas fields. W h e n a n oil field starts to peter out, engineers often inject gas or water u n d e r pressure into the pool to squeeze more oil to the surface.
Two-piece aluminum jackets to cover insulated pipe elbows fit snugly to the insulation and join smoothly with jackets covering straight p i p e
Otherwise more than half the oil might remain locked in the earth. But injection is not enough. T o determine how efficient the secondary recovery process is, it is necessary to know what happens to the injected gas or water—how much is doing the j o b a n d h o w m u c h is being wasted or lost. M a n y types of tracers—fluorescent dyes, boron compounds, ammonia, helium, carbon monoxide among them—have
Injecting radioactive krypton gas into pressurizing well a t oil field. Krypton-85 was pressurized t o almost 1 0 0 times atmospheric pressure so that it would flow into the well VOL. 50, NO. 5
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MAY 1958
25 A
