704

IRON.

the other, leaving a space between them. This annular interval amounts to 16 inc ,e ' iand it is closed at top and bottom: but the innermost cylinder is open at both ends, a eforms, indeed, the vent of the chimney or furnace. It carries nine rows of pipes, 0“in each row, which cross its interior, and open into the annular space. . „

The flame of the furnace passes between the intervals of the cross pipes, ^them, and also the two upright cylinders with which they are connected. The airthe blowing machine arrives by a vertical pipe, which is placed at the back of the h ^nace ; it enters into the above annular space, and thence circulates, with more or -velocity, through the 27 cross tubes, upon which the flame is continually playing; * oS v[it is drawn through to the bottom of the annuiar space; the two tubes which condnto the two tuyeres, pass down within the brickwork of the furnace, and thus preventdissipation of its heat. ■

Below this heating apparatus there is a door for putting the charges into the furnaThe above arrangement does not seem to be the best for obtaining the greatestble heat for the blast, nor for favoring the free action of the furnace; hut it ’*' ustl ^ en tperfectly well the principle of this application. A serpentine movement in a longhot channel would be much better adapted for communicating heat to so bad a conu°as air is known to be. . pei-

In the month of July, 1836, 1 paid a visit to Codner Park andButterly works, i n ff(1 cbyshire, belonging to the eminent iron-masters, Messrs. Jessop & Co., where 1 g|]( ikindly permitted not only to study the various processes of the manufacture of c aS ^j^twrought iron, but to inspect the registers of the products of cast iron in their ^furnaces for several years back. It appeared that in the year 1829, only 29 t0 ^.j ie ycast-iron were made weekly in each of the blast furnaces at Codner Park. j re jjwere then worked with coke, and blown with cold air. Each ton of iron ret I w iihfor its production, at that time, 6-82 tons of coals, made into coke for smelting > g j-2-64 of roasted iron ore (carbonate), called mine; and 0-87 of limestone, the casthe French . , . a ni

In 1835 and 1836, the same furnaces turned out weekly 49 tons of cast-iron eac ;every ton of iron required for its production only 3 tons of coal (not made into2-72 tons of mine ; and 0 - 77 of lime. j. sail

In 1829, and for many years before, as well as one or two after, each ton of coa)s j j n toto have cost for coking the sum of 6s., whence the 6-82 tons of coals then conver - ltB ecoke for smelting one ton of iron, cost fully 40s. in coking alone, in addition toj. t ]iecost. The saving in this respect, therefore, is 40s. upon each ton of iron, besi _ ^ flta lsaving of fully half the coal, and the increased produce of nearly 60 per cent. ° ^ jie

per week. The iron-master pays the patentee Is. upon every ton of iron permakes, and, at the prices of 1836, he lessened his expenses by at least 30s. orton by the patent improvement. .. 0 f the

The following tabular view of the progression in the management and re .his counWhot blast, is given by M. Dufrenoy, after visiting the various iron works in thwhere it had been introduced. effect

“ At the Clyde iron works, near Glasgow ; in 1829, when the combustion was

by the cold air blast,-

There were consumed, for smelting, 3 tons of coke, equivalent to— for the blowing engine -

Total coal per ton of ironLimestone - "

In 1831, with the hot blast at 450° F., coke being still used in smelting,-There were consumed, for smelting, 1 ton, 18 cwt. of coke, equiva-lent to --------

— for heating the air, 5 ewt. ?

— for the blowing engine, 7 cwt. 4 ibs. )

Total coal per ton of iron *Limestone - ■

In July, 1833, with the hot blast at 612° F., raw coal alone being usefor smelting,—

There were consumed : for smelting "

— for heating the air

— for the blowing engine -

■ Total coal per ton of ironLimestone

Tons.

. 6

. 1

. 7. ‘0

Coal.

cwt*

13

0

~13

lot

6

12

9

0

8

11

1197