LUNDIN'S FURNACE.

The following table shows the results for the first year of working of the saw-dust heating furnace, at Munkfors during the year 1866, compared with the results obtained from the charcoal furnaces of the Society of Uddeholm. The two coal furnaces served at the same time as reserves, and have only been worked when the other was under repairs. During the first six months the yield was 789 tons of bar iron, and in the last six months 1,013 tons, of which 557 tons was during the last three months, or at the rate of 2,229 tons per year.

The column containing the consumption of carbon of wood not coked per ton is calculated on the assumption that a cubic foot of charcoal contains eight pounds of pure carbon, and that 50 per cent. of the richness of the wood in carbon is lost in coking. The column shows, therefore, the real consumption of carbon per ton of iron made.

In comparing the consumption of fuel in the saw-dust furnace with that of the charcoal furnaces, it will be seen that the first was able to heat three hundred weight of iron with the same quantity of combusti ble that the latter would have required for one hundred weight, and this though the former works with wet fuel.

The latest results of the saw-dust furnace are as follows: From November 10, 1866, to April 18, 1867, or during 105 days of 24 hours, a yield of 926 tons of bar iron, with a waste of 12.04 per cent., and with 268 cubic feet saw-dust per ton of iron. One week showed a yield of 56.18 tons, with 219 cubic feet per ton, the waste being only 9.9 per cent. At present the waste does not exceed 11 per cent. (April, 1867.) Table showing the results of the working of the saw-dust furnace at Munkfors during the year 1866, comparatively, with the results obtained from the charcoal furnaces of the Society of Uddeholm.

Year of operation, 1866.

Consumption, per ton.

Saw-dust furnace at Munkfors. 206. 111, 839. 96 104. 99 1, 532. 30 11. 77 274
Two charcoal furnaces at

EXPLANATION OF LUNDIN'S FURNACE.

Plate I.

All the parts of the furnace are easy to manage, and all the work is regular and solid. The reheating furnace is rarely repaired oftener than every five or six weeks; the repairs only require one or two days at most. The most frequent are only the upper portions of the regenerators, which require to be changed. The condenser is only opened and examined two or three times per year. The gas generator is not cleaned during the week, unless this precaution is rendered necessary by the use of impure saw-dust, or dust mixed with sand; and, in any case, this presents no obstacle to the work. Usually the cinders formed during the week are piled at the side of the neighboring wall every Saturday evening when the work is finished, and it is not necessary to undertake a careful cleaning or to remove the refuse, except when the generators are prepared. The tube of the conduit between the gas generator and the condenser requires to be cleaned every week; but this cleaning, which can be easily made during the working of the furnace, does not prevent the heating. Also, generators of a larger size require cleaning much less often.

SUPPLEMENT BY LUNDIN.

a. This is only the hygroscopic value of the water. Dust containing a larger quantity of water may be employed. Fresh dust often contains 50 per cent. That containing 60 per cent. cannot be used long alone, (this makes 80 per cent. by the addition of the chemical water,) but, mixed with pieces of wood or with good dust, it may be employed with advantage.

b. The quantity of carbonic acid may be removed by the use of quicklime in the condensing water. The lime may subsequently be used for agricultural purposes, but the effect of the acid is seldom considerable. c. The auxiliary furnace has worked since January, 1866, from the same generators and condensers which belong to the heating furnace. At present 21 to 28 cubic feet of saw-dust are consumed for the heating and incandescence of a hundred-weight of iron in bars. In the charcoal gas furnace 101 to 13 cubic feet of coal are employed, and sometimes more. Consequently, the real consumption of carbon in the latter is 100 pounds to one hundred-weight per hundred-weight of iron, on account of the loss by the burning of the wood.

d. The two or three upper layers of the generators of the heating furnace must ordinarily be renewed every four or six weeks, but the other layers, as well as the regenerators in the auxiliary furnace, last much longer.

y, z. Tube for the water which cools the gas by means of eight streams having a diameter of inch. The jets are broken against points of copper

directed towards the centre of the openings of the jets. The pressure of the gas in all the conduits is inch of water.

Condenser of cast-iron plates.-This contains 3,700 pounds of iron, in bars, kept cool by water from the pipe y y, in order to cool the gas and precipitate the water. Fifteen and a half gallons of water, heated to 30 Centigrade, flow in a minute when working with the reheating furnace alone. Nearly double will be required when working with the auxiliary furnace at the same time.

Thirty-six gallons of tar are collected per week.

The tube y y turns back and forward by an angle of 1200, to wet the bars, situated below, by means of small holes.

Reheating furnace with Siemens' regenerators.-The furnace may be placed at a long distance from the condenser. The temperature calculated from the cold air used to burn the gas is about 2,000° Centigrade. The following shows the composition of the gas, which is the same before and after the condensation:

The mixture before condensation contains 33 parts by weight of water to 100 of dry gas. (For other details, see explanations upon the plate.)

AW 1323

18,500 41, 832 44.2 69.8 40.8

100,000 328

7,200

15,616

1,049

2,276

11, 380

AW 1313

18,000

41, 924

43.0 67.8 38.1

..do..

1314

100, 000

.347

30.7

do

1322

7,050

15,060

46.7

2.44

1,028

2, 196

10,980

Do.

18, 250

41, 878

43.6 68.8 39.5

100,000

.338 29.9

7, 125

15, 338

46. 4

2.30

1,038

2,236

11, 180

WC 1293

20,000

44, 532

44.9 55.8 31.5

.do.

1299

100,000 .320

28.3 ..do

1287

7, 200

15,728

45.8 1.88

1,049

2,293

11, 465

Do.

WC 1298

19, 750

43, 780

75.4 40.0

100, 000

44.2 2.37

WC 1303

73.6 41.2

100, 000

GROVE, SOUTHWARK STREET, LONDON, S. E., July 20, 1867, Messrs. A. FRODING & Co., Gothenburg, Sweden, per Mr. S. H. LUNDH, 9B, New Broad street, London.

STRESS IN POUNDS PER SQUARE INCH.-EXTENSION AND SET, INCH.

PULLING STRESS.

STRESS IN POUNDS PER SQUARE INCH.-EXTENSION AND SET, INCH.