128 The Philippine Journal of Science i9i8 



Clogging of the gas flue and the delivery pipe. — When the 

 producer is not fully charged there is considerable deposition 

 of dust and small particles of impurities in the gas flue and in the 

 delivery pipe, necessitating a cleaning about every two weeks. 

 Under this condition the distance from the hopper valve to the 

 surface of the fuel bed is considerable. The gas flue, which 

 is under suction all the time, is located between these two levels. 

 Naturally when the coal is fed into the producer through the 

 hopper valve, it falls in front of the gas flue, and small particles 

 of coal and dust are sucked in and deposited in the flue and in 

 the delivery pipes. Running the producer full prevents the 

 serious clogging of the pipes, and a more uniform gas is obtained. 



As another means of avoiding clogging of the flue and the 

 delivery pipe a hole was made in the center of the three-way 

 cock fitted with a removable plug. Through this hole a scraping 

 rod can be inserted, even when the producer is in operation, to 

 remove any deposit in the flue. The vertical and the short 

 horizontal delivery pipes were also provided each with a nozzle 

 for water supply, which can be kept in operation when a long 

 run of several months without stop is desired. 



Centrifugal separators. — The circulating water in centrifuge 

 1 was found to contain ammonia from the gas and tar. The 

 ammonia present attacked the brass blades of the centrifuge to 

 such an extent that complete renewal within about four weeks 

 was necessary. Iron blades were substituted, and from that 

 time no more trouble from this source was experienced. 



Hopper. — The hopper used for coal and lignite (fig. 6) was 

 found to be unsuited for the mixture of coconut husks and shells 

 due to its small opening and capacity. A special hopper for 

 this fuel was designed, as shown in fig. 9. 



CARE AND MAINTENANCE 



The care necessary in a producer-gas plant is less than that 

 required in a steam plant of the same capacity. In the producer 

 plant there is no boiler. This obviates the need of the continuous 

 attention of at least one fireman, who is required to throw small 

 amounts of coal into the boiler furnace at short intervals, dis- 

 tributing it evenly over the grate surface in order to attain high 

 efficiency in operation. The only attention required in such a 

 producer-gas plant as that at the Bureau of Science is to charge 

 the gas producer full or nearly so every one or two hours when 

 coal is the fuel, which takes about ten minutes of the fireman's 

 time, and to draw out the ashes and clinkers about every ten 

 hours, or requiring in each operation about fifteen minutes. 



