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zontal axis. Of the two principal adaptions of the system to an entire window, Hurwood's, shown in fig. 808a., and worked by an endless screw, is the simplest; there is another arrangement of this kind by Mackrory, where the action is similar to that of a carriage window; the sash runs in a groove, and being turned by means of a toothed pivot working against an endless screw, it can be kept at any desired height. The method indicated by fig. 808., adopted at Middlesex Hospital, seems more simple and more economical. By turning the handle to the points in the plans A, B, and C, the glazed louvres are simultaneously opened or shut to those limits.

[graphic]

B

Fig. 808.

2278p. Ventilation is effected on the principle of the extracting valve, as advocated by Dr. Arnott, which is a plate of metal hinged to the lower edge of a metal box next to the room, and on the other open to its chimney. The draught of the flue tends to carry away the air of the room, when the currrent is upward; should it be downward, a silk or mica flap is driven against Fig. 808a. the plate, tending to prevent the ingress of smoke. However useful this contrivance may be, its result in cubical consumption of air is necessarily small. A cowl with vertical, or horizontal, or slanting jalousied sides has also been employed, with or without an Archimedean screw, at the top of a flue, to exhaust. the air of a room. The simplest means of the admission of air to a room is a hole in front of which, on the inside, should be a board inclined to throw up the current of fresh air, as fig. 808b. Another well-known invention is Sheringham's inlet ventilator. An opening is made in an external wall for the introduction of air, and a metal box inserted, which is a sort of hopper, having at its mouth a valve, so hung as to direct the current of air towards the ceiling, whereby no draught is felt by the occupants of the apartment. Somewhat similar is Hart's ventilator, the face being of perforated zinc. Such articles are also made with a box to contain charcoal as a purifier of the air before it is admitted. Looker's patent ventilator, consisting of a tubular piece of pottery fixed in the wall, into which on the inside is placed another tube, perforated all round with small holes, the inner end being closed altogether. This second tube is pushed in or out, according to the quantity of air required.

WALL

Fig. 9086.

2278q. Amongst the earliest of other and later systems is Watson's double-current ventilator, consisting of a tube divided by a diaphragm, and rising from the ceiling to the external air; it was intended that the air should circulate, as shown in fig. 808c., by an

ascending and a descending current. It has
been said that this result only occurs in rooms
that are perfectly closed, and that the two tubes
generally serve as exhausters; but our own ex-
perience is more favourable to the effective
working of this invention. Somewhat similar
to this is fig. 808d., called the Shaftesbury
ventilator, which appears to have been applied
in small tenements with success, probably for
the very reason that the rooms in such cases are
generally kept as close as possible; for it has
been necessary to conceal the opening at the
ceiling by an ornamental rose, and to put at G
an air grate with large openings. At times,

H

Fig. 808c.

Fig. 808d.

Fig. Sose.

however, the rush of cold air is very great through this tube into the room; to remedy this, the end G may be connected with a horizontal tube or box about 3 feet long, and somewhat larger than the tube H; each end of this box is open, but filled with very fine wire gauze; the result then has generally proved satisfactory. A modification of

the preceding invention is adopted by McKinnel. Two concentric tubes are so fixed that the inner one is longer than its envelope. This apparatus, shown in fig. 808., nearly answers its purpose, according to certain authorities, and certainly gives, in some cases, a result that would be satisfactory if its regularity were not affected by atmospheric influences. The openings require to be covered, so as to prevent the admission of rain. A square turret, diagonally divided, as shown in fig. 808f., is known as Muir's ventilator. The inventor calculates upon utilising the slightest current of air, as he supposes that when it arrives at one of the sides it will enter, descend, and force an equal quantity of foul air to discharge itself at the other sides. The report of MM. Blondel and Ser upon the London Hospitals in 1862, states broadly that none of these methods gives a satisfactory solution of the question.

2278r. Honeyman's diaphragm ventilator, 1886, is prepared for use for open timber roofs and for ceiled apartments. Air pressing in on one side shuts a valve on the windward side of a middle diaphragm, passes through an orifice in it, creating an upward current in an air trunk, which draws out the foul air in the room through other valves on the lee side. When there is no wind, the valves on both sides of the diaphragm open freely for the exit of the heated air.

Fig. 808/.

WALL

INSIDE

22788. The system of Mr. Tobin (of Leeds) for providing access of fresh air into a room is now extensively used, and sometimes under other names. It was promulgated by him about 1874, and although the principle is of an earlier date, it is to his endeavours that it has become recognised as a most valuable auxiliary. The principle is that of a tube carried up from the floor against the inside of an external wall to a height of about 7 feet. Fig. 808g. shows a section of the tube on this principle, from Dr. Corfield's Laws of Health, p. 41. The bottom of the tube is made to communicate with the outer air and the top is left open. This tube may be made of planed deal or metal. The top is by some manufacturers covered by a piece of coarsely perforated zinc to prevent articles dropping down the tube Others put in a coarse canvas bag to filter the air as it passes through into the room. A regulating valve is also sometimes provided, but this is best avoided, as when once shut it is not always opened again. A "deflecting shield" is often added to the top to prevent the wall decorations from being marked by the dust often in the air passing in. Inlet brackets are also made, which are short tubes placed high up, but their efficacy may be doubted. They are also called "vertical tubes" and "air inlets" by some manufacturers. E. H. Shorland,

Fig. 808g.

of Manchester, claims to have used "vertical pipes for ventilation" long before they were introduced by Tobin. The opening on the outside of the wall should be protected by a grating a patent automatic air washer, for washing the air by a spray, is adapted by some to this system, as also the introduction of gas lights for warming the air.

TABLE OF CUBIC FEET OF AIR DISCHARGED PER MINUTE THROUGH A VENTILATOR, HAVING AN AREA OF ONE SQUARE FOOT. (Hood.)

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The openings for the inlet of fresh air must be smaller than those for the escape of the heated air, otherwise there will probably be a descending current of cold air in the same

tube with the ascending current of hot air. It is now proved that all inlets should admit the air in an upward direction.

2278t. The Eolus waterspray ventilator is patented to supply a constant circulation of pure air entirely under control. It is adapted for all public edifices, as well as houses, stables, &c., and for use in hot climates. Ice can be used to cool the fresh air, and a gas furnace can be attached to warm it. The air passing through the apparatus is cleansed from dust and all impurities. The consumption of water is stated to be small, and the total cost of ventilating and warming a large apartment for nine hours does not exceed sixpence. The company has also an exhaust roof ventilator, a waterproof downcast shaft ship ventilator, an automatic invisible roof ventilator, a chimney cowl, and a ventilating stove. 2278. F. H. Smith, patentee of the automatic syphonic aspirator system of ventilation, which produces ventilation without draught by supplying air to the room by ducts at the floor level. The exit for the vitiated air is placed in the ceiling, and consists of two tubes, a large and a small one, parallel to each other, between the floor joists. In the case of top rooms the two tubes may be concentrical. The larger tube carries off the foul air, while the smaller one forms an induction tube for cold air, its outer extremity being open to the outer air, the inner one opening under the rim of the foul air tube. The principle was applied to the hot" island room" of the fountains of 1884 Exhibition, reducing the temperature from 110° to about 70°. The Eon ventilators, extractor, and ehimney cowl are stated to be the cheapest and most effective used with the eon inlet. The Acme system of ventilation (Liverpool) is an exhaust and blower type, dependent on mechanical action for its motive power. The action of the ventilator produces a partial vacuum at each stroke, and with the graduated pipes fresh air is brought into rooms without draughts, and may be warmed as it enters. The system has been applied at the new County Sessions Courts, at the Town Hall and Council Chamber, and at the Conservative Club, all at Liverpool. Its application at the former building is described, with an illustration, in the British Architect of December 2, 1887. Westmorland's patent improved automatic ventilator combines an iron breast trimmer and fireproof hearth bearer (1885), to carry the air from a ceiling up into a smoke flue. The ventilating and warming arrangements of the new portion of Eton College (1888, A. W. Blomfield, architect) have been carried out by J. Weeks & Co., by air passing over hot water coils, and the foul air carried off by ducts at the ceiling of the passages to a shaft having a series of gas jets to secure an updraught.

2278v. Where gas lights are much used in apartments or buildings, it is desirable to carry off the products of combustion and heated air by a tube placed over the light, whereby its heat assists the escape of the impure air. An ordinary gas-burner is calcu-, lated to vitiate, to the same degree, three times the quantity of air that a man does in the same time. This plan was first effected by Professor Faraday. The improved ventilating sun-burner, with its self-acting valve for preventing a down draught, as manufactured by Strode and Co.; Rickets's ventilating globe-light; and others, all tend to produce the desired result..

TABLE OF QUANTITY OF AIR REQUIRED PER HOUR TO MAKE UP FOR VITIATED AIR BY. FORMS OF ARTIFICIAL ILLUMINATION.

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2278w. The Commissioners for Barracks and Hospitals, in their Report, 1855, p. 65, &c., state that for such establishments the different systems adopted in the Parisian hospitals appear to be too expensive and too complicated. Those which they approve consist of induction, and of flues for exhaustion, each of two sorts. Induction.-I. Openings with an air-brick in the face of the wall, and a wooden hopper near the ceiling, placed at an angle of 45°, covered with zinc pierced with holes from to inch in diameter. A plate of zinc or galvanized iron, hung at the bottom and worked by a string, regulates at pleasure the admission of air, the size of the opening being calculated at an inch square for each 60 cubic feet of space in the room, where there is not a special provision for fresh air to pass round the stove; when there is such provision, the size for the opening may be one half less. II. Openings with an air-brick in the face of the

wall, and a trunk or tube leading the air to a case behind the stove, so that warm air may rise in a tube to a luffer-boarded opening at the ceiling, the size of the tube being calculated at an inch square for each 100 cubic feet of space in the room.

2278x. Exhaustion.-I. Flues of the warming apparatus extract the bottom layers of air in the room. The experiments made between 4.30 and 6.30 A.M. in April, 1858, showed that the volume of air extracted was on the average 9,000 to 10,000 cubic feet by each flue, the rapidity being at the rate of 5 to 5 feet; by which numbers the section of the flue would be 0-446 English feet. II. Tubes from the ceiling to the roof, the size of the opening being calculated at an inch square for each 50 cubic feet for an upper story, and for each 55 cubic feet for the story below it, and for each 60 cubic feet for the lower story. The rapidity of the current is regulated by the difference between the internal and external air, by currents, &c. When the temperatures are equal the current is feeble, when the reverse occurs it is strong. The volume extracted (under the abov conditions) was 8,500 to 9,000 cubic feet, the rapidity being at the rate of 3 to 3 fent. So that the greatest effect by the combined systems only takes 8,000 to 10,000 cubie feet by each flue on the average, and this irregular result is sometimes annulled; moreover, the currents may reverse the action of the flues, and enter by the exhausting tubes. 2278y. Other systems.-In the new buildings at Guy's Hospital, as also at the Lunatic Asylum at Derby, Sylvester's method was carried out. Here the air arrives by a large inducting flue, capped by a cowl which utilises the action of currents of wind; the air passes underground in contact with hot-water pipes, rises in flues, and enters the room at the ceiling; it escapes by exhaustion holes in the skirting of the opposite walls, and rises to the roof by flues continued by plate iron tubes to an exhausting flue, which surrounds the smoke flue of the warming apparatus. The inventor calculated for about 4,000 cubic feet per bed per hour, and stated that in the winter about 4,300 had been obtained generally, but that once about 2,200 only were gained.

22782. The methods of ventilation adopted in France are required to produce effects absolutely free from perceptible currents of air. The report produced by MM. Blondel and Ser, before noticed, mention Duvoir-Leblanc's system, in one portion of the hospital Lariboisière, as drawing away about 2,500 cubic feet per bed per hour, half of which is supplied by the doors and windows; and the method of MM. Thomas and Laurens, which gives 3,200 cube feet per bed per hour, and is not found always sufficient to remove every trace of odour. They consider that Dr. Van Hecke's system, used at the Baujon and Necker hospitals, leaves much to be desired. They require 3,500 cubic feet per bed per hour; and perceive that in order to obtain anything like such a result, recourse has necessarily been had to large exhausting flues, or to mechanical means, such as the fan.

TABLE OF AIR REQUIRED PER HOUR FOR EACH PERSON.

Prepared by Herr von Fragstein of Berlin (Builder, xliv. 1883, 56).

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Each person is considered, in England, to require from 3 to 5 cubic feet of air per minute, equal to 180 to 300 cubic feet per hour. At Finsbury Technical College about 11 cubic feet of air per minute is provided in the class rooms, and 50 cubic feet per minute in the chemical laboratories and draught closets.

SECT. XIV.

WARMING OF BUILDINGS.

2279. Heat, as required in architectural structures, results from raising the temperature of the air by means of various contrivances so arranged as to take advantage of the laws which govern the transmission of heat. A body capable of affording heat gives out caloric by two methods; these are radiation and conduction. Radiation is diffused through the air at an immense velocity without materially raising its temperature, but immediately warming solid bodies exposed to its influence, which in turn give out the acquired heat slowly; the redder the fire, the warmer is the radiant heat. When the air in a large apartment is to be raised in temperature, the method of heating by contact is employed; this is effected by volumes of air coming in contact with a heated surface, and, becoming raised in temperature, are put in motion, and communicate the heat they receive to surrounding bodies.

2279a. In order to obtain full advantage of heating surfaces, their area must be pro

portioned to the cubic feet of air required to be warmed. A small surface, if raised to a very great temperature, will heat a large quantity of air if means are taken to pass it rapidly from contact with the heated surface. It is better, in all respects, to have a large surface maintained at a mild temperature with a gradual change of air. In general, if the temperature of the heated body is above that of boiling water, i.e. 212°, the air in contact is rendered unhealthy. Ventilation very greatly assists the endeavours to warın successfully a room or building.

22796. The method of warming classed under radiation and conduction may be further arranged under the following heads:-I. Open fires, including grates and stove grates of every sort, having ordinary flues or chimneys; this is warming by radiation. Warming by conduction is effected by, II. Close fires, as furnaces, cokles, &c., and the Cabin, Arnott, Vesta, Gill, Chunk, Dumpy, Nott or American, laundry or ironing, caloric, ventilating, &c. stoves; and by Gas, as the atmopyre, asbestos, calorifere, cylinder, and gas heating apparatus; baving metal or brick flues continued some distance from them for the purpose of heating. III. Hot water on the low temperature system, with pipes about 3 or 4 inches in diameter. IV. Hot water on the high temperature system, with pipes about 1 inch in diameter. And V. Steam, both on the high and low pressure systems. 2279c. The principle of erecting one chimney to serve for all the fire places of a house is liable to very unsatisfactory results, unless such a system be carried out as that exhibited at Osmaston Manor, near Derby, by its architect, H. J. Stevens, and described at the Institute of British Architects in 1851. All the rooms in Fair Oak House, Isle of Wight, are warmed by means of one shaft in the middle of the house, heated by a large open fire in the basement. Around this shaft is a thin enclosing case of brickwork, in cement, leaving a space between to receive the cool air, which is then warmed by the heated shaft, and is admitted into the several apartments through perforated cornices, the supply being regulated by a valve. Obstacles presented themselves which rendered it necessary to adopt the cornice and not the floor as the place for the admission of the warm air. The arrangements are stated to have met with a decided success; the plan and details are given in Builder, 1860, p. 329. In a series of small dwellings where the one shaft system was tried, its complete failure necessitated the new formation of all the fireplaces and flues.

2279d. I. It scarcely enters within the province of this work to describe the best form for an open grate. The point has been taken up of late years by manufacturers, and very many excellent forms adopted. The result is that iron at the back and sides has been greatly discarded, and fire-lumps substituted, whereby greater heat is thrown out with the same quantity of fuel. The fire-lump grates for cottages, bedrooms, schools, &c., have had a large sale. But it has also been found that too large a surface of the fire-lump tends to consume the coal too quickly, consequently it is now chiefly confined to the back of the grate. A length of bar equal to about 1 inch for each foot of length of room, and the height of the front half an inch for each foot of breadth of the room, are dimensions found to produce good proportions for average purposes. The depth of the part in which the fuel is placed has been greatly decreased, about 9 inches being ordinarily sufficient at the bottom, and enlarging upwards at the back, so as to present a good heating surface in the front, and at the top, of the fuel. The height that the lowest bar should be from the hearth is a matter of greater uncertainty; we advocate that it should be as near to 12 inches as possible, in preference to the 6 inches which the grates are now usually made. We have had grates raised from the latter to the former height with greatly increased results. Advantage has been taken of the fire-clay stoves, since the period of their invention by Count Rumford, to combine the back and sides with air flues of the same material, which, becoming heated, impart their heat to the cold air supplied from the outside, admitting warm fresh air to the apartment. These stoves were first adopted by Cundy. Numerous forms of slow-combustion grates have been introduced of late years. The Carron, Musgrave's, and Barnard, Bishop & Co.'s Norwich stove, are among many others of that description. The registered Economiser grate and fire-brick back, manufactured by Nelson and Sons, of Leeds, on the principles advocated by T. P. Teale, in Economy of Coal in House Fires, has a door to the ash-pit to close the draught; the sides and back of the fire are of fire-brick, while above the fire the back slopes forward and over it to near the mantel, when it again slopes back to the back of the chimney; all this being in firebrick and channelled where above the fire. It is considered to give perfect combustion of fuel, with complete radiation and projection of the heat produced, the form of back ensuring the greatest possible consumption of smoke. It can be readily fixed by any bricklayer. The Marlborough grate (Garland's patent), with adjustable canopy acting in place of a register door, fire-brick sides and back on the same principle with Economiser; when the fire is not used, the canopy can be let down to shut up the flue opening, like a register. Radiation of heat has been materially assisted by Sylvester's arrangement of the ends of the fire bars projecting into the room forming a hot hearth; and also by Joyce. Dr. Arnott's smoke-consuming grate, and the application of a solid bottom to a grate, producing the Builder's fire," are points of consideration for the householder rather

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