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Channel Ferries (Continued from Page 14) easily carried out. A feature of the pressure parts is the entire absence of bolted handhole doors. Fach boiler is designed to give 16,000 pounds of steam per hour, superheated to about 500 degrees Fahr. From feed water at 270 de- grees Fahr. The working pressure is 250 pounds per square inch, Under these conditions the temperature of the air to the stokers will be from 350 degrees to 400 degrees Fahr. The airheaters are of the latest Yarrow horizontal type in which the air passes through the tubes while the gases pass across them. This new design of airheater occupies small space and is of light weight. / Automatic Underfeed Stokers In a coal producing country like Great Britain, it is a matter of na- tional importance to use coal as fuel wherever it can be done without sacrificing efficiency. Since the pro- pelling machinery of these vessels must of necessity be placed below the train deck, the use of coal as fuel is particularly advantageous as it is possible to run a train load of coal cars immediately over the bunkers and to tip the coal directly into the bunkers. However, it was only after careful examination of the advantages of various schemes of propulsion that it was decided to use coal as fuel. It was found that it would be possible to obtain the fullest advantage of coal as fuel by using watertube boilers and automatic mechanical stokers with self trimming bunkers leading directly into hoppers of the stokers. In this way the coal ‘‘flows’’ to its work, not being touched by hand in any way. The only manual labor required is the removal of ashes from the special ashpits at the end of the fire grates. Yarrow watertube boilers fitted with Taylor underfeed stokers were selected. In order to test thoroughly and to demonstrate the efficiency of this particular combination, one of the boilers was subjected to an ex- haustive series of trials at varying loads and with different kinds of coal. Because of the proximity of Dover to the Kent coal fields, experi- ments were made to determine the best type of Kent coal for use on the train ferry. Conditions of service were repro- duced at the trials, the boiler work- ing under forced draft in a closed stokehold. A Yarrow-Terry turbine type of fan of standard design, as fitted in many vessels, was used. The tests were highly successful. Com- bustion was very good and the fur- nace conditions showed that the coal burned out completely before it reached the ash pit at the end of the stoker. Perfect combustion, it 40) was found, depends on the regula- tion of the speed of the fan. The stokers, as shown in the ac- companying illustration, are of the retort type which have already been introduced successfully by Yarrow & Co. in several important merchant vessels. They are supplied by the Taylor Stoker Co. Ltd., and in this particular case have been designed to meet the special conditions of service and to burn a wide variety of coals. As previously mentioned the bunkers are arranged so that the coal feeds by gravity to the stoker hoppers. From the stoker hopper the coal is thrust by each fuel feeding ram into one of four retorts which are buried in the fuel bed below the zone of combustion, or, in other words below the level of air admis- sion, The coal is stored in these four retorts until such time as it is re- quired by the fire above. Order of Ignition No combustion can take place in the retorts because the fuel has been pressed into them with _ sufficient force to exclude all air pockets, but insofar as the coal in the retorts is able to ‘‘feel’ the heat of the fire above, there is a continuous and gradual rise of volatile matter from the whole length of each retort, which continues upwards until a level is reached where air admission takes place. When, therefore, the fuel which is stored in the retorts is required for combustion it is gradu: ally raised by the stoker mechanism to the level of air admission by which time it has been completely devola- tilized and issues from the top of the retort in the form of porous coke. This process is a continuous one, fresh coal being fed into the bottom to take the place of the coke issuing from the top of each retort. The coke issuing from any one re- tort meets the coke issuing from ad- jacent retorts across the intervening air admission zones, and thus the fire bed structure extends in one con- tinuous coke mass across the entire width of the stoker. When the vola- tile matter reaches the air admission level, it is picked up by the preheat- ed air draft, from forced draft fans, which is being forced upwards through the fire bed. The preheated air and gases then “churn” their way together upwards through the maze of interlacing passages formed by the coke bed, Accordingly, on reaching the incandescent surface of the fire bed, the carbonaceous gases are so thoroughly oxygenated that com- bustion proceeds with extreme rapid- ity and shortness of flame. It is, therefore, axiomatic that the sreater the compactness of the coke in the fire bed, the greater is this scrubbing or churning action, the more thorough is the oxygenation of the gases, the shorter is the flame MARINE REVIEw—September, 1934 from the fuel bed and the more in- tense is the radiant temperature ef- fect of the fuel bed surface, It is ap- parent that one very important ele- ment in design of the stoker is to keep the fuel bed moving without destroying the homogeneity of the coke mass above the air admission zone. This is achieved by moving the fuel bed as a whole by the system of reciprocating pushers which operate in the bottoms of the retorts, and which are designed to do their work without disrupting the crust of the fire. Without Grit or Smoke The importance of the above, in marine design, is at least two-fold. In the first instance, homogeneity of the coke structure above the air ad- mission zone is a definite asset in marine stokeholds where headroom is limited, because short flaming combustion is the primary essential of efficient steam generation where combustion chamber volume is re- stricted. In the second place, the tightly packed and homogeneous fuel bed structure is the prime es- sential of gritless and smokeless funnel emission, Westinghouse Business Up Westinghouse Electric & Mfg. Co.’s report for the second quarter of 1934 shows a total of $33,655,022 for orders received, as compared with $20,237,- 588 for the previous quarter and $17,- 557,964 for the second quarter in 1933. Sales billed for the second quarter of 1934 totaled $27,287,545 as compared to $17,994,045 for the previous quar- ter and $15,926,335 for the correspond- ing quarter in 1933. A net profit of $1,744,427 is shown for the second quarter, as compared to a net loss of $1,776,152 for the previ- ous quarter and a net loss of $2,078,- 424 for the corresponding quarter in 1933. Total operations for the first six months of 1934 show a net loss of $31,- 725 as compared to a net loss of $5,- 569,996 for the same period in 1933. According to F. A. Merrick, presi- dent of Westinghouse Electric & Mfg. Co., orders received during the quar- ter ended June 30 show an increase of 92 per cent over the same quarter in 1933. Orders received during the six months ended June 30 show ap in- crease of 77 per cent over the corre- sponding six months of 1933. An interesting new bulletin on gen- erating sets has been issued by the Troy Engine & Machine Co., Troy, ka; The new bulletin covers a complete range of sizes for both vertical and horizontal engine driven generators for direct and alternating current and for both marine and stationary service. The information is very complete and clear and there are nu- merous illustrations.