Document KYDGgEOaJD55YX7VQvrLReZ6

Marmaduke's Flying Propeller Every marine doileo has a bottom* blow valve and o *urface-blow valve. And every time we see a letter on the right or wrong way to install a blow down valve we think of Mormaduke SurfaceMovr. Then we wonder U hie name hat any connection with marine boiler*. Now that reader* hove had their chance to get into that valve argument (*ee "Arguments," in the loal few is sues) we thought Marmy might like to lock it up by putting in hi* oar. When we entered the eld consulting engineer's dingy office obove O'Houlihen's Machine Shop and Engine Works, we found him burning up someone at the other end of his telephone. "If she threw a propeller blade, radio your chief engineer to slow her down until she doesn't vibrate. Keep running a< that speed until you eon get her into shipyard. That* what t lAro. And don't worry. I once ran al) ilio way from Seattle to New York with a blade off." Slamming down the receiver he spoiled me. "Make it snappy," blasted Marmy. "This la my busy day." "Mow about settling that argument in Powen on installing blowdown valves with the pressure under or over the seat,** I began. "Bilcewatbo on ntowoown valves," bellowed -Marmy. "Vtl tell you about a ship's propeller that almost knocked itself out." With that he hoisted hla feet onto his roll-top desk. Then he reached over to the potbellied stove, grabbed the cof fee pot and (mured himself a cup of black stuff that looked and smelled like hunker-C fuel. Before I could osk why this sudden change from Sandpaper Gin, he put the steaming cup down and roared: "fleck in 1913 I was Chief on the freighter SS Valparaiso. She was steam reduction-gear job. We carried general cargo to the west coast of South America. On our return trip we brought back copper, fruit, coffee and nitrate. "The yalparaho was sn old ship. But my engineers were good, hardwrirk'mic men who had al) come up through the foc's'le. They kepi that old rust bucket running on schedule. "One trip the Valparaiso pulled inlt Mobile, Alabama, to dry dock for the annual shipyard overhaul. Besides *U,, the repairs we were doing below, the shipyard was to pull our tail abaftThat meant removing the propeller sad breaking the 4-in.-diameter eoupllftl' bolts on the l6-ln.-diameter tall shift . down in the shaft alley. "Because a tail shaft Is flanged on * the inboard side, It must be removed- hy pulling it back through the stem tube inside the ship, after the propeller < is off. To do<htt, the last piece of shell*. ing before the tail shaft must be lifted out of the way. And a 16-in.-diameter shaft of about 10-ft length Isn't lightThen the tall shaft is pulled Inside through the Hern tube to be examined. "The shaft ojley Is narrow, with t catwalk along the shaft. And the shaft' ing bolted together Is from 100 to lS ft long, depending on distance betweenengine end propeller. Every ten fee* there ere large spring bearings support'' ina the shift. / "The 4.[n.-dimneler coupling boW (Continued oft page 172) **1144 HAN! OPERATION AND MAINTENANCE SECTION PO % When eilicn scale was mentioned, water-treatment experts used to change the subject quickly . .. until a plant using The Nalco System began having scaling troubles due to high silica content of the row water. That was many years ago.Today, the same plant, oper ating at 135 psi, maintains 500 ppm (29.4 groins-per gallon) silica in boiler water without scaling. The Nalco research program that solved this lowpressure boiler water silica problem Is a continuous one, so that today The Nalco System successfully meets the challenge of silica wherever it-arises in. the Held of water conditioning. Whether your water treatment problem U silica--or something even louaher--Nalco has the solution, or cau put the full facilities of the Nalco Laboratories to work on it for you. LATEST STUDY ON SILICA CARRY-OVER At operotlng pressures ove( 400 psi another silica problem--(hot of silica carry-over--often arises. One of the 1951 ASME papers, Correlation of Silica Carry-over and Solubility Studies* Is an up* to-lhe-minuto. Informative discus* slon of this problem. You oro welcome to a copy. Just write to National Atumtnofe Corporation. NATIONAL ALUMINATE CORPORATION 6322 W. 66th Place Chicago 38, Illinois Canadian inquiries should ho addressed to AUbtm Limited, Burlington, Ontario *W| - JUIY IPS) Serving Industry through Practical Applied Science