. Railway mechanical engineer . n air-operated fire door. In making road tests, wherethe coal is not actually weighed it is the usual practice toplace an observer in the cab to record on a tally sheet thenumber of shovelfuls of coal fired during the trip. Where adynamometer car is used each shovelful may be recorded di-rei tly on a counter in the car by means of a push button andan electric circuit from the cab to the car. Neither of thesemethods is entirely satisfactory, however, because it requiresan extra man in the cab. It is also quite likely that his at-tention may be diverted from time
. Railway mechanical engineer . n air-operated fire door. In making road tests, wherethe coal is not actually weighed it is the usual practice toplace an observer in the cab to record on a tally sheet thenumber of shovelfuls of coal fired during the trip. Where adynamometer car is used each shovelful may be recorded di-rei tly on a counter in the car by means of a push button andan electric circuit from the cab to the car. Neither of thesemethods is entirely satisfactory, however, because it requiresan extra man in the cab. It is also quite likely that his at-tention may be diverted from time to time, when he will losecount of a few scoops of coal. The simple device illustrated registers every time the firedoor is opened and with a good fireman this is practicallyequivalent to registering the number of scoops of coal cvlinder isturned out of brass and accurately finishedto a diameter of 2 in. on the inside. In this cylinder is a sim-ple brass piston 1;m in. long, working easily in the cylinder Binding Posf. —j Counter for Use with Pneumatic Fire Doors bore. The lower end of the cylinder is turned with a boss,into which is screwed an air pipe leading to the fire doorcylinder. The upper end of the counter cylinder is threadedand into it is screwed a 2-in. plug about -54 in. long. A\.-in. hole is drilled out in the centei of the plug, into whichi- driven a piece of oak, turned with a small shoulder onone end to keep it from working up in the plug. The oakpiece is drilled for a 3/16-in. bolt, which passes up throughthe wood, the head projecting into the cylinder. This formsone terminal of an electric circuit and the other is formedby a small machine screw in the pipe plug. To these termi-nals are attached the wires connecting with the counter andbattery in the dynamometer car. At the top of cylinder, justbelow the plug, are drilled four ^s-in. holes to allow any airthat may pass the piston to escape. When air is admitted to the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
