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86 Oil Purifiers Needed (Continued from Page 80) kept a very careful check on _ the amount of oil purified and the quan- tity of sludge removed from the puri- fier, gives a good opportunity to show how fast sludge accumulates in the crankcase when purification is not continuous. The LINNELL’S engines are of a design calculated to prevent much dropping of carbon into the crankcase and the cooling system is ONE OF THE TWO CENTRIFUGAL OIL PURIFIERS ON THE M. S. EAST INDIAN, USED FOR THE LUBRICATING OIL FOR THE TWO 2500 BRAKE HORSEPOWER SUN-DOXFORD ENGINES so tight that very little water is removed from the oil: Nevertheless, on one voyage during which 2200 gallons of oil was purified, a total of 211 pounds of dirt was removed. Another trip, 74 pounds of dirt was removed from 1320 gallons of oil. ‘Another showed 85% pounds removed from 1340 gallons of oil and a fourth showed ‘921% pounds of dirt removed from 1400 gallons of oil. The re- moval of this dirt has made it pos- sible to keep the present charge of oil in service for nearly three years during which time no radical bearing adjustments have been necessary. Perfect Lubrication on Long Trip The J. W. VAN DYKE which re- cently completed without refueling, the longest voyage ever attempted by a vessel of this type, is equipped with a centrifugal oil purifier. The Van DYKE is said to be the larg- est diesel-electric ship in the world and is owned by the Atlantic Re- fining Co. Her record-breaking voy- MARINE REVIEW age was from Philadelphia to Rio de Janiero, thence to Durban, South Africa and return, a distance of about 15,000 miles. At the end of this voyage an inspection of the bear- ings of her three 840-horsepower In- gersoll-Rand oil engines, which are of the oil-cooled piston type, showed it to be unnecessary and indeed im- possible to make any adjustments so’ perfect had been her lubrication. As indicating as to what might have happened, it is interesting to note that during the voyage the oil purifier removed from 40 to 45 pounds of dirt from the oil every twenty-four hours. The statement of one engineer that his oil purifiers removed just about one ton of carbon from lubricating oil during a six-weeks voyage will appeal to those who like to think in big figures. Considering the fact that the engines on this ship are rather small, this record of carbon removal is extraordinarily high and obviously results from faulty engine design. We understand that this sit- uation has since been corrected but cannot refrain from pointing out the fact that if the carbon had not con- tinuously been removed from the oil by centrifugal purification, there would shortly -have been nothing of the original engines left to correct. Electric Winches, Reliable (Continued from Page TA) prove their worth for general cargo. handling. How Duty is Determined In determining the “duty” of a suitable electric cargo winch, the following factors must be considered: average weight of the drafts of cargo usually handled; maximum weight likely to be handled on a single line; maximum load to be handled and number of parts of tackle available; desired tonnage capacity per hour. This determines the required rope speed and size of motor based on heating characteristics. Most ship operators will emphati- cally state, when discussing electric winches for a ship they propose to build, that they handle heavier cargo or have more severe service than any other steamship lines’ using electric winches successfully. Usu- ally a careful investigation and time study shows that their service re- quirements fall well within the range of the standard winch. Studies of many steam and electric winches in service show in almost every in- stance that the average draft handled November, 1926 is under one ton; that there are seldom more than two or three con- secutive drafts of over two tons; and that it is very rare to find two steve- dores who will handle more than three tons on a single line. Using these facts for “rule of thumb” computation, the winch for general cargo handling should be designed for a rated load of about two tons with ample overload capaci- ty to handle frequent: loads of three tons and _ sufficient mechanical and electric strength to take occasional overloads up to five tons. Such a winch will not only handle the single line drafts but: also the mul- tiple port and derrick boom lifts up to about 30 tons. Above this, a heavier winch or additional gear re- duction is generally used. General cargo can seldom be han- dled at a greater rate of speed than 40 tons per hour. Frequently the winches are not run nearly to capar city but must wait for the steve- dores to hook on the cargo or take it away. This fact has lead to the belief that a rope speed of about 200 feet per minute for average drafts is all that can be used to advantage unless the ship has very deep holds or handles continuously some light uniform cargo such as bag sugar or case oil which permits of high speed and high tonnage ca- pacity. For the average winch, there- fore, a motor rated at 25 horsepower on a 80-minute heating basis is found to be ample. Electrical Equipment Necessary The general outline of electrical equipment consists of a water tight motor, preferably series wound, but with compound winding if much winch head operation is expected; a shoe type solenoid brake; a straight line drive controller with overload and under voltage protection and with full dynamic braking control for low- ering. There is still much discussion as to whether the so-called cam type drum controller or the master switch with full magnetic contactor panel control is more desirable. A study of the two indicates that the magnetic control reduces current peaks, pro- vides certain features of operation not found in the cam controller, is relatively fool proof in the hands of an inexperienced operator, re- quires fewer renewals of contact tips and is applicable for any horsepower. The cam controller presents fewer parts and much simpler construction, and is more readily understood by a third rate electrician or steam en- gineer. It gives satisfactory serv-