INJECTORS: THEIR CARE AND UPKEEP.
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Valuable Advice from Our Driver and Mechanic Readers.
.I. T SEEMS as though a steam wagon driver may be judged, in comparison with, as well as by, his fellows, by his handling of the injector when it is well, and his care of it when it is ill... This is not to say that we get a great number of letters on the subject, but rather that we are considerably impressed by the tope of those we do get.
"J.B.," for example, accompanies a very useful contribution to current literature on the subject of injectors by a most elaborate sketch of the water supply sys tem of a Foden wagon. ' -
• .The experience about which he writes to us is admittedly a common brie. " Pickit up." That is the phraSe one hears so • frequently amongst steam Wagon drivers when they discuss injectors. One will say, "My injector refused; to pick :.up water" the other day,and another will ansvier, feelingly; "and so did • mine." This then, was what happened to "JIB.," who hails from Chesterton—his injector " refused to pick up water." Now this is a serious matter, involving, in the or
dinary course, drawing the fire, letting down the steam, and a whole host of minor troubles of that kind.
Happily, on this occasion, a brain wave swept over " J.B.," and lie thought of a means for getting over this difficulty of the injector "refusing to pick up" ; his' idea, moreover, proved to be practicable, and to achieve the desired object; He hastens, therefore, to pass it on, knowing how frequently this trouble of injectors "refusing, etc.," crops up. We, in our
turn, reproduce his sketch, -and repeat his communication ;• for" the general good, _returning good for good, this time, to "J.13.," by awarding him the 15s. prize, which he well deserves.
He stopped up the overflow tole in the tank, using a piece of waste cloth for the purpose, screwed the top of the water lifter down tightly, and turned steam into the tank. This drove the water along the pipe until it reached the injector, whichwas then set to work and functioned quite happily. The idea seems to be: if the injector will not pick up its water, drive the water to it.
Anyhow the plan worked like a charm, and " J.B." is now thinking of putting a special pipe in he overflow hole in the tank, and providing himself with a wooden plug, or plug of some sort, which he can use at any time.
For ourselves, we are net too keen on the overflow pipe, which will have the effect of raising the possible level of water in the system, nor do we like the idea of fitting a solid plug in the end and turning steam into' the tank. The waste cloth was all right, it could not hold pressure; a plug is a different matter, and might bring trouble.
Now. .."J.11." was ingenious; but " G.H.C." is a pra.ctical engineer. He has no use for waste clothe or dummy overflow pipes. He makes a finished job of his gadget and, what is more to the point, he really masters this recalcitrant injector fellow.
Take off, he advises, the right-hand cap of the injector, that cap which is at the delivery -end, and solder a piece of brass sheet., A-in. thick, on to its outside face, so as to thicken it. Then drill a hole through the centre of a size to tap out to .4-in. gas, and subsequently tap it out
accordingly. . •
Into the hcle thus made screw a brass pet-cock, taking care that the screwed end of the cock does not project through into the inside of the cap, as if it does, it.. will obstruct the water pas. sage, which is most undesirable. Replace cap, complete with pet-cock, and all is in readiness against the time when the old familiar trouble recurs.
The procedure is then: Open the petcock and operate the injector in the usual way, apply steam gently until water flows through the cock, which must then be closed. Apparently, the provision of an opening at the point where the cock is fixed offers a straight. passage for water, with a minlidurn of frictional resistance, the injector working .then in a similar manner to the water-lifter to the tank. At any rate, " G.H.C." has never known this device to fail in com pelling the injector to pick up. . Of course, the principle behind this tip is anything but new; as it has long been the practice, in similar circumstances, to take off the delivery end cap altogether, thus affording, in even greater measure, therfreedom of passage which is provided by the open petcock.
Both "J.A." (of Peterborough) and " T.H. (of Kidderminster) have realized the difficulty of grinding-in the valves of steam wagon clack-boxes and injectors. The ordinary, method, using a screwdriver engaging a hacksaw cut fit -the top of the valve, is net practicable; because the valve, being: hemispherical, rocks about too much on its seat. These two correspondents• describe methods which eliminate this diffieultV and enable a _good contact between verve and seat to be obtained.....
." T.H." takes a piece of steel bar and puts it in the lathe, where he turns it up until its exterior is a nice fit in the bored part of the valve seat. While it is still in the lathe chuck he bores a hole up one end to accommodate the collar on the valve. This completes his tool ter the grinding operation, save for fitting a ---in. setscrew, with which the valve is held.
"I.A." makes a bush, the exterior of which is the same diameter, as the interior of the valve seat,"' and bored to fit the valve collar. The bush is used to 'bold the valve central and vertical, whilst the screwdriver is used in the. t•ime-honotired fashion.