KIL

89

KIL

arches in the front wall are filled up with bricks almostin } 6 room left in each sufficient only for putting

, the furze, which is done in small quantities, the objectQf 11 ?? t0 keep up a constant and regular flame. In the space*•“ii'ty-six or forty hours, the whole limestone, about 120,^ quarters, together with 15,000 or 20,000 bricks, areoioughly calcined. Kilns constructed in this way may beD]. n n<;ar Wellingborough, in Northamptonshire , and otherCes ' n the northern parts of the kingdom. In many ofnorthern counties of Scotland , which are situated at aj eat distance from coal, it is also a common practice to burn]jjj est °ne with peat ; and, considering the rude ill-constructedtyi 8 w hicli are used for the purpose, it is astonishing with(]j . . suc cess the operations are performed. In some of thesehe * s stated that limestone is sufficiently calcined with

e\vi S ’ &t -ratum super stratum, in kilns formed of turf; butq !'S to the quantity of ashes which fall from the peat, the“ty of the lime is considerably injured; and, from theof f 1 an .^ ex P°sed situation of many of these kilns, the wastelj Ue * >s immense. But the most common method of burningto *1 '° lle w 'th peat, is in kilns constructed somewhat similarIn i • e * n the districts where furze is used as the only fuel.d,. c j 51 ‘ n s of this description there are, in general, only twoof t j es > or fire-places, and the peats are thrown into the bottom\ V ]. 'I *' 86 arches, the fronts of which are seldom closed up, bytl ] 6 C 1 ® e ans the wind has often great influence in retardingtio n °P* ra ti° n , and frequently prevents the complete calcina-te l ' le ^ mest °ne. An improvement might, it is supposed,;ic ' e on these kilns at a very trifling expense : if an ironIjj e "'ere laid across the bottom of the arch, with a placeol 0s t°*' the ashes to fall down, and the front of the archtnlr,! U l1 P by a door made of cast-metal, one-third of the fuelu n | 11 te saved, and the operation performed in a shorter time,pc 'r'tt a much greater certainty, than by the method nowj n ' Se d in such kilns.

a communication to the Board of Agriculture, Mr., hi( 8 °n described a method of constructing a lime-kiln, by'IV* 1 con siderable saving of fuel was effected.

Mac-j 8 ^fin was ma< I e 20 feet in height ; at the bottom wasto

‘Ced

the

! l .th e .

a metal plate, one foot in height, intended to give airle fire ; the sloped sides were 6 feet in height, the breadthcm a * e to p of the slope 8 feet; the sides carried up perpendi-to I'l feet; so that every part of the inside, from 14 feettttouth, was exactly of the same dimensions. On the

fatf

In

°I the kiln was placed a cap, built of long stones, and

sharply contracted, about 7 or 8 feet high. In the

Ov

g of this cap, on one side of the slope, the mason be-er the centre of the kiln, anything dropping downfall perpendicularly to the eye beneath. Here wasan iron door 18 inches square, and then the remaindert building of the cap was carried up until the whole of

tvas contracted to 14 inches. The kiln was fed

tittup

Sfi the iron door, and, when filled, the door was closehp t 0 9 a be outside wall was 3 feet at the bottom battering^ 6et at t0 P> ant I Built at such a distance from theVjj 'vail of the kiln, that 2 feet of yellow clay might bekilUjj b ac ked in between the walls ; without this precautionthgalmost certain to split. At 8 feet high from the eyeS kiln, two flues were carried through the front wall,t ke packed clay to the opposite sides of the kiln, toV t {h^ er to the fire. It is asserted, that, with this kiln,i'ty r . more lime has been produced from a given quan-go tv 'tck and also that stones of bad quality might be put

tfie v i ~. —-.— — i- ■> —®r~

U$ u , K >tn without the necessity of being broken so small

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Ij 1 ' 2o' p man y situations will not admit of building av t® 1 st high, while other situations may allow of itsfit 30, or even 40 feet, (for it cannot be made too

2 a

high,) the diameter of the kiln should be proportioned tothe height to which it is carried up.

In the same communication, Mr. Rawson also describedanother and rather curious application of this sort of contri-vance. He states that, “ for several years, he has made useof a small kiln in an outside kitchen, the height 9 feet, thediameter 3^ feet. In the side of the kiln next the fire, he |had 3 square boilers placed, one of them large, containing ]half a barrel, with a cock, which supplied the family with !constant boiling water ; for the two others, he had tin ves- !sels made to fit the inside with close covers, in which meat |and vegetables with water were placed, and put into the two 1smaller boilers, which never had any water, but had close icovers. The tin boilers were heated sooner than on the jstrongest fire, and when the meat, &c., were sufficiently [dressed, the whole was taken out of the metal boilers. At 1one side he had an oven placed for roasting and boiling meat; jthe bottom was metal of 26 inches diameter, and 11 inchthick, a flue from the fire went underneath. Even with thebottom of the oven, a grating 9 inches square was placed,which opened a communication between the oven and the hotfire of the kiln. The height of the oven was 14 inches,shut close by a metal door of 18 inches square, and the top,level with the mouth of the kiln, was covered by anothermetal plate of half an inch thick, on which was placed asecond oven ; the heat which escaped through the half-inchplate, though not near the fire, was sufficient to do all smallpuddings, pies, breakfast-cakes, &c. &c. The meat in thelarge oven was placed on an iron frame, which turned on apivot, and stood on a dripping-pan, and was turned by thecook every half hour. And over the kiln he had a tiled stagefor drying corn, and a chimney at one side, with a caul onthe top, which carried off all steam and sulphur: a largegranary was attached to the building.” It is added, that thelime, if sold, would more than pay for fuel and attendance ;and he has frequently had dinner dressed for fifty men, with-out interfering with his family business in any great degree.

An admirable combination of a lime-kiln, with a coke-oven,was the subject of a patent granted to Mr. Charles Heathornsome years ago, since which time it has been in successfuloperation at Maidstone and other places. The object of thisinvention, as expressed in the specification of the patent, isthe preparation of quick-lime and coke in the same kiln atone operation. The economy of this process must be evi-dent from the circumstance, that the inflammable part of thecoal, which is separated to form it into coke, is the only fuelemployed to burn the lime ; and as the coke is in manyplaces as valuable as the coal from which it is prepared, thecost, if any, of making lime, must be reduced to the mosttrifling amount.

In burning lime, some burners prefer peat to coal for thefuel; but that preference has probably arisen from an inju-dicious management of coal. Mr. Dobson asserts peat to bemore economical than coal; that coal, by its excessive heat,causes the limestone to run into solid lumps, which it neverdoes with peat, as it keeps them in an open state, and admitsthe air freely ; that the process of burning goes on moreslowly with coal, and does not produce half the quantityof lime.

This inconsistency requires no comment ; nevertheless, !peat is a very useful fuel for the purpose, and an excellentsubstitute for coal, where the latter is scarcer or dearer.All kinds of lime exposed to the air recover nearly theiroriginal weight, except chalk-lime, which, although longexposed, never recovers more than seven - eighths of itsoriginal weight. Some limestones, as Portland-stone, yield avery white lime ; others, as chalk and roe-stone, a lime vvitk