For DRIVERS, MECHANICS & FOREMEN.
Page 45
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TEN SHILLINGS is paid to the sender of any letter which we publish on this page. and an EXTRA FIVE SHILLINGS to the sender of the one which we select as being the best each week. All notes are edited before being published. Mention your employer's name, in confidence, as evidence of good faith. Address, A, ..11. and F., "The Commercial Motor," 7-15, Rosebery Avenue, Landon, E. C. /,
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Getting Home on One,Cylinder with a Steam Wagon.
Quite a considerable arnount of interest appears to have been .aroused by' the letter written ,b "A.J.D.," and replied to by " H.M.," under the above heading.. It, will be remembered that," A.J.D." had an accident to the L.P. piston pod of his steam wagon, and after a little trouble, succeeded in getting home after.he had blocked up the L.P. piston in the cylinder, running on the H.P. only. In his description of his experiences' he omits to state whether. he made any alteration to the valve gear, and we, and our readers, are therefore left with the impression that he made no such alteration. "JIM." wrote, pointing out that, so far as his experience went, it would not be possible to run -with the engine at all unless the L.P. valve was disconnected. The follotving letters show the opinions of other readers:— The sender of the following communication lies been awarded the extra. payment of .5s. this week. .
[2,104] " WAIT:" (London, S.E.1.) writes :—" I have. been very much interested in the discussion which has been going on in connection with the letter written by ' A.J.D.' under thei•above titleeand while. I nein with HA.' that different treatment must be afforded to different types, and makes of engines, It differ from him in respect of his statement in regard to the necessity for disturbing the LP. valve.
think'A.J.D.' could very easily have got home without interfering, with it at all, by carrying on in the following manner :—
" Make Use of the three-way cock which is provided for turning the exhaust steam from the H.P. cylinder into the funnel instead of into the valve chest of the L.P. cylinder. He could then work with the high pressure engine only. He would probably' find, however, that the L.P. slide valve would cut grooves on its facing if it was allowed to run with the engine working as I have suggested, for in that case it would be getting no oil at, all, since the usual method of lubricating it is by meansiol the oil carried. through in the steam. For which reason, if for no other, it might be preferable to detachthat. valve. "However, I see no reason why the engine would not work passably well with the L.P. valve left in place, and with the steam taking, as far as possible, its normal course from the H.P. cylinder to the L.P., for, as the valve is still eonneeted-to its gear, it would travel to and fro overedts ports, admitting and releasing the steam just as if thee piston was -working.' There would be no accumulation of steam in the L.P. cylinder as nrophesiediby EM.' "I had a little experience recently with a steam wagon, and brief reference to it may not be entirely out of place • in oonection with 'this matter. Thew i wagon n question was a Foden, and, on one occasion the H.P. eccentric, for some reason unknown, ran hot, and the' eccentric rod bent under the strain. I took off both the rods on that side, uncoupled the big end of the connecting rod, pushed the piston up to the front of the cylinder, and tightened the gland on to the rod se as to prevent it from moving. I then took off the high pressure valve • cover, and moved the valve into such a positior, that it covered both steam ports. I then ran home, using the-regulator as set for double high pressure working. I have since thought that I could have managed just as well if I had taken the H.P. valve right out, arid used the engine with.the regulator set in the ordinary position as for compound working. In that case the steam would have run straight through the H.P. cylinder into the low without doing anywork in the high."
[2,105] " J.H.R." (Leiston) writes :—" A.J.D.' did not make it quite clear in his letter that the type of engine which he was driving at the time of the oecurrence in question *as fitted with double high pressure gear, but I think that we may presume that such was the case. In that event. as' H.M.' has evidently overlooked, it would not be at. all necessary to remove or tamper with the L.P. valve gear. All that is necessary is that-the valve which is provided for diverting the H.P. exhaust direct to the chimney, instead of, as usual, to the steam chest of the L.P. cylinder, should be placed in.the position for so diverting the steam. At the same time, the. engine should still, be worked as if running in the ordinary way, that is to. say, compounded. In that fashion the wagon would run 'quite, satisfactorily, and no difficulty would be encountered -by the exhaust steam from the H.P. cylinder accumulating in the L.P. "It would, however, be necessary for the auxiliary lubricator, which is provided for the L.P. cylinder, to be put to work, as otherwise the L.P. slide valve would be iinlularicated, since the oily exhaust from the H.P.,-on which-it dependsoin the. ordinary way, for lubrieation, would not be akailable. -Great care would have to be taken that the double high pressure gear was not put to work, as in that case full steam wbuld be turned into the L.P. cylinder."
[2,106] "Leyland" (Reading) writes :--" It should be quite possible' for A.J.D.' to run•with the L.P. slide valve coupled up. The .exhaust from the H.P. cylinder, in those circumstances' could have been got rid of in two ways:--(1) By 'turning the three-way cock to the double, high pressure position, the exhaust would have been diverted direct to the chimney and the engine run satisfactorilylon the one cylinder. (2) The-exhaust steam could' have got away through the L.P. cylinder and valve,in the ordinary way through the working of that valve, as the valve would still continue to traverse to and fro over the ports, notwithstanding thatithe piston in the cylinder was held up. A little back pressure might have been caused, asethe. result of wire drawing at that end, of the cylinder to which,the piston was ,,pushed, but nothing like so much as prophesied by H. M.,' and certainly not to such an extent as to stop the working of the H.P. cylinder."
[2,107] " J.D." (Sandbach) writes:--u The engine would have ,worked. as described by `A.J.D.,' although there would havebeen a, certain amount of back pressure caused, at least at one end of the cylinder, The better way would have been to open the three-way cock which allows the exhaust from. the H.P. cylinder to pass direct to thefunnel. In the ease, however, of an engine fitted with an auxiliary valve, or by-pass, this method of working would not have been possible, and `A.J.D.' would have been better. advised to take out the L.P. valve."
"A.J.D." himself writes—"In reference to my previous letter on the subject .of gettingrhorne on one cylinder, I regret that I omitted to mention that before attempting to run on again I removed the L.P. valve and sealed up the stuffing box, afterwards replacing the. steam chest cover."