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that the result is a spreading of the coal continuously rather than firing it in separate charges.

Some fifteen or sixteen of these stokers have been applied to locomotives to date, and are firing the locomotives successfully.

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Drawing showing arrangement of Hanna stoker.

This is a drawing showing the general arrangement of the Hanna overfeed scatter type locomotive stoker. The peculiar characteristic of this stoker is the use of a combination of movable mechanical directing means and continuously operating steam jets for distributing the coal over the grate area. It also has means for crushing the coal preparatory to forwarding it to the elevating and firing means.

The driving motor is a twin-cylinder, double-acting steam engine placed on the locomotive tender, usually in one of the forward ends of the water space. The operating routine is to have the coal passed to the crusher through the opening in the deck of tender, and after being crushed the coal is forwarded by a cast-steel helicoid screw to a receptacle at the base of the elevating means, which is another cast-steel screw placed in the vertical casing just at the left of the ordinary fire door of a locomotive. At the top of the elevating means is a large elbow, or goose-neck, through which the coal is forced by the pressure of the vertical elevating screw and finally falls by gravity over the directing vanes, or wings, to the firing plate placed inside of the regular firing door of the locomotive.

This photographic view shows the firing plate, above which will be noted the main nozzles of the firing jets placed in fanshaped arrangement, and above these jets will be seen the ridge plate and movable mechanical means or directing wings, which serve to assist the jets in distributing the coal over the grate area.

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Photograph showing views of firing plate, steam jet nozzles, and stoking mechanism of the Hanna stoker.

Just below the main jets is a long slot in the casting at the level of the firing plate, and this can just be seen in the view.

The operation of the mechanism shown in this view is about as follows: The coal reaches the vanes at the upper part of the opening, coming by gravity from the goose-neck, and these vanes are in turn operated by the levers placed on backhead of locomotive, which will be shown in the next view, these levers keeping the vanes in constant motion while the stoker is in operation, which results in the coal being poured down over the jets, and the stream of coal is gradually directed from side to side, so that

the jets pointed in any given direction intermittently force part of the coal, as it is directed over them, to some portion of the grate area; these jets being arranged in the segment of a circle, and the passing of the coal gradually from side to side in front of them has the effect of waving the coal over the grate area from one side of the firebox to the other. Steam also is forced against the coal through the long slot just below the main jets, but at a lower pressure, and this serves to force part of the coal just over the firing plate to the back of the grate area.

This delivery of the coal to one side of the firebox for a short time and the similar delivery in turn to the other side would make it proper to classify this stoker with those of the intermittent firing type, as a charge or "fire" is, in a partial sense at least, delivered to the different sides of the firebox and allowed to burn until the cycle of mechanical movement brings another delivery of fuel. The jets are constantly in action, the mechanical direct

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Photograph showing the adjustment levers for control of distributing wings of Hanna stoker

ing means are also continually in motion, but the delivery of the fuel is intermittent-an arrangement just opposite from that of most stokers of the overfeed type.

The fan-shaped arrangement of main jets serves also as a fork, or set of fingers, to partially separate the coarser lumps of coal from the fine slack, which latter drops to the firing plate and is forced to the grate area by the low-pressure steam emitted from the long slot just mentioned; the larger particles are more violently forced by the steam jets to other parts of the grate area.

This is a photograph of one of the earlier forms of the Hanna stoker, but will serve in this connection to show the arrangement of control levers which operate the movable mechanical means which assist the steam jets in distributing the coal as just described, this lever arrangement being the same in the present installations of this stoker as shown in this view. The hopper shown was the receptacle into which the coal was shovelled manually. The moving of the small levers on the quadrants here shown has the effect of changing the range of movement of the directing wings so that the coal may be kept directed toward a limited part of the grate area, or by moving these levers on the

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Photograph of backhead of locomotive showing Hanna stoker device lowered for hand firing.

quadrants the range may be changed so that the movement is over the entire grate area.

It will readily be appreciated that as this stoker is applied to the ordinary fire door of a locomotive it is essential that some means should be furnished for getting the stoking mechanism out of the way in the event of failure, or for the purpose of building the fire at the round-house by hand, and this view shows the upper part of the elevating means and the goose-neck, but the main stoking mechanism has been lowered below the deck of the locomotive cab. At the left of the goose-neck will also be seen. the quadrants and operating levers shown in the other view.

Approximately forty of these stokers have been applied to locomotives to date, about twenty of which of the latest design are in daily service and firing locomotives successfully. About twenty of the earlier forms of this stoker, with which the fireman was required to shovel the coal into the hopper below the elevating means of the stoker proper, were applied to locomotives, but found to be either not practical or of sufficient advantage to warrant their continued use. Those at present in service, however, are giving good satisfaction.

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This is a drawing showing the general arrangement of the Crawford mechanical underfeed stoker as in use on a large number of Consolidation and Pacific type locomotives on the Pennsylvania Lines West.

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