The Mechanical Handling and Storing of Material
Forfatter: A.-M.Inst.C E., George Frederick Zimmer
År: 1916
Forlag: Crosby Lockwood and Son
Sted: London
Sider: 752
UDK: 621.87 Zim, 621.86 Zim
Being a Treatise on the Handling and Storing of Material such as Grain, Coal, Ore, Timber, Etc., by Automatic or Semi-Automatic Machinery, together with the Various Accessories used in the Manipulation of such Plant
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THE MECHANICAL HANDLING OF MATERIAL
2. The impossibility of obtaining reliable statistics of a plant suitable for British
requirements.
3. The large size of coal mined in England.
4. The class and size of coal wagons in use.
5. The restricted area available in most steam-shed yards.
6. The regular and adequate supply of coal between colliery and steam-shed.
7. The high cost of land for extensions and alterations to yards.
8. The impracticability of one plant capable of dealing economically with coal between
(i) wagon and tender; (ii) wagon and stack; and (iii) stack and wagon or tender.
9. The varied local conditions existing at steam-sheds on any one line.
10. The large outlay necessary for installing a plant, and the cost of working various
plants.
11. The breakage of coal.
It is unnecessary to enlarge upon points Nos. 1 to 5, but as regards No. 6 it is
found that, in those countries where long distances separate collieries from locomotive
depots, it is absolutely necessary to keep large stocks of coal on hand, to carry over
delays or stoppages; such stacks really represent a combination of current and stock coal.
They are, so to speak, continually on the move, and the conditions render it essential to
install mechanical means of readily taking up or putting down the coal, manual labour
being out of the question from a commercial point of view.
The economical and commercial points have been dealt with fully in Mr Cooke’s
paper, and want of space forbids their mention here.
With regard to breakage, it has been stated, on the authority of results of actual
experiments in America, that “ each per cent, added to the slack means a reduction in
earning capacity of the locomotive of about Id. per ton of coal fired, besides an average
loss of unburned1 fuel itself of another |d. per ton for every 1 per cent, of slack.” This
should emphasise the desirability of handling coal in such a manner that the minimum
quantity of slack will be formed. The large amount of slack created by the present
manual handling is perhaps not generally realised, and the following statement may come
somewhat as a surprise. After a tender had been loaded in the ordinary manner, and the
coal had been broken by the fireman to a suitable size, the proportion of slack left ranged
from 13 per cent, in the case of Welsh coal, to 2’3 per cent, in the case of North Stafford-
shire coal, although particular care had been taken to start the experiment with wagons
from which all slack had been removed by hand.
When to this is added the slack which is in the wagon when it arrives at the coal
stage—in this case 10-2 per cent, in soft coal, and 2'9 per cent, in hard coal—the total
is sufficient to make one pause to consider how this waste may be avoided. (In this test
“slack” means all the small coal which was passed by a riddle with |-in. mesh.)
Mechanical plants should therefore be designed with a view of dropping the coal as
few times as possible between wagon and tender, minimising the height of fall, sliding
the coal where possible, and delivering it in such a size that no additional breaking by
the fireman is required.
At the Crewe north steam-shed, at which about 130 engines are permanently
stabled and about the same number are coaled daily, the quantity of coal transferred
from truck to locomotive every twenty-four hours is about 450 tons, or 140,000 tons
per annum.
The plant, which is shown in Figs. 879 and 880, consists of a wagon tipper, an
1 This is the small coal which is lost through being drawn straight through the tubes as soon as it
reaches the firebox, or which is blown off the tender.