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a AA Li Sa ale a 8 ~ New System of Tank Cleaning Saves Time and Expense 2 By L. E. Browne offensive and difficult problems in the transportation of crude and refined oils and chemicals by water. Gas-freeing and tank cleaning by a crew with hand hose is a tedious, long and expensive operation. Progress in elimination of time, ex- pense and danger with additional ad- vantages of better cleaning has at- tracted much interest on the part of tanker owners and operators in the system of tank cleaning developed by Butterworth ‘System Inc., Bayonne, N. J. A group of oil shipping operators attended a demonstration of the ma- chine manufactured by this company on the T. J. WILLIAMS owned by the Standard Shipping Co. at Bayonne, N. J., recently. The system has been adopted on the tankers of the Stand- ard Shipping Co., the Sinclair Naviga- tion Co. and numerous other tankers. This system makes it unnecessary for men to enter the tanks until they are gas-free and dry. Tanks are washed by a machine with heated water directed against the plates of the interior of the tanks in a solid stream at high pressure from revolv- ing nozzles. The machine is projected into the tank from a small hole in the deck. The deck hole is so placed as to pre- vent fouling of ladders and beams by the nozzles, there being two nozzles on each machine. The machine is operated by an air motor, easily at- tached, although it should not be in place except when the machine is not operating. The nozzles are a fixed part of the machine, which, when the equipment is in place, reaches down to about one half the depth of the tank, and as near the center as pos- sible. Nozzles turn slowly on a horizontal and perpendicular plane, the direction of the water stream changing with each revolution. As a result, the stream eventually reaches every part of the interior surface of the tank. The system provides for ship instal- lation of its own hot water plant, all equipment being available on the tanker. Circulating water from the condenser at approximately 110 de- grees Fahr. is sent to two evaporators in series. The temperature is gradual- ly raised from 160 to 175 degrees. It may be pointed out here that a hand hose crew could not handle a line of this temperature, much less one with a pressure of 175 pounds, which is the force at which this water is thrown. It is also important to note that a solid stream of water hits the interior Tom cleaning is one of the most chambers of the tank, and not a spray. The evaporators connected in series the steam and water pass through in opposite directions. Steam is admit- ted to one evaporator, its condensate and excess steam led.to another which receives the warm water direct from the condenser. From the second eva- porator the condensate is led to the hot well and, as a result, no fresh water is lost to the system. After - passing through both evaporators, the hot salt water goes directly to the fire pump which discharges into the 83-inch fire line at about 175 pounds per square inch. To provide a reserve heating capacity for the water, provi- lYa" High 2D g Diagrammatic Sketch Showing Tank Cleaning Machine in Operation in Main Cargo Tank sion is sometimes made to inject live steam into the 38-inch line; but with both evaporators operating, the live steam injection is hardly necessary. About 400 gallons of hot water a minute is driven on the tank plates. Sediment and oil residue are flushed into the suction of the cargo pumps which may discharge overboard at sea or into salvage tanks. Under this system of tank cleaning best results may often be had at sea. Pipe standards for most deep main tanks are about 20 feet long while for summer tanks they are shorter, gen- erally around seven feet in length. The interior shaft connected with the nozzles and operated on deck by the air motor revolves slowly. Best re- sults are found in operating the air motor at the lowest possible speed which is approximately one revolu- tion per minute of the nozzle shaft. With employment of this system, it is claimed that a large tanker can be gas-freed in from 20 to 36 hours MaRINE Review—July, 1931 and that tanks can be cleaned from black to refined oil in from three to six days. Condition of tanks and type of oil previously carried naturally are important factors as to time required. Two men of the ship’s personnel can operate and perform all the labor re- quired, the only work being that of shifting the machine from one tank to another. The machine also removes rust scale, retarding corrosion and eliminates the need of steaming. Dur- ing cleaning operations tanks are well stripped, keeping bottoms free of water thus realizing the full force of the streams on the tank bottoms, which results in the breaking up of rust scale so that it is pumped out with the water. When cleaning from black to re- fined oil it is sometimes necessary to wash with kerosene or furnace oil. For this only a comparatively small amount of cleaning oil is required and it is circulated through cleaning ma- chines at high pressure in the same way as the water. All parts of the machine from the operating air motor on the deck are of brass or bronze with the exception of the shaft which is steel. This eliminates the danger of sparks while raising or lowering the machines into the tanks. When not in use machines are carefully stowed on racks to pre- vent damage from bending or other- wise. After each cleaning operation air motors should be cleaned, filled with grease and stored in a dry place. To Get Mexican Subsidies Ocean going and coastwise pas- senger and freight ships of Mexican registry and which have Lloyd’s or other similar classifications, an which can develop a minimum speed of seven knots, will receive subsi- dies from ‘the Mexican govern- ment under new merchant marine regulations that have been decreed by President Pascual Ortiz Rubio. The regulations specify that the owners of ships seeking these _ subsidies, which will vary according to the class of ship and allotments for this purpose made in the federal annual budgets, must make contracts with the ministry of communications and public works, Mexico City, in which the tonnage and other specifications of the craft will be given. The steamship LEVIATHAN, flagship of the United States lines, will make a summer cruise to Halifax, N. S., July 23, returning July 2, in accordance with authorization granted by the shipping board on June 10. The cruise will in no way affect the regular schedule of sail- ings maintained under the sales con- . tract transferring the United States lines to their present owners. This eruise will mark the first appearance of the world’s largest ship in a Cana- dian port. 31