Part 12

The shape of the back brick advocated by Dr. Teale (first invented by the celebrated Count Romford, to whom much is owing for the various means undertaken by him to promote the consideration of the question of improving our fire-grates and to abate the smoke nuisance) has since its discovery met with universal favour, and is coming into general use by all makers, as the expense of the stove is scarcely increased and its result in use is a most decided improvement. The actual shape or section of this brick varies with the different stove makers, but the result is the same; the brick is made to slope forward from the bottom up to about 15 or 16 in. high; at that height the top of the brick overhangs the bottom by about 5 to 6 in.; its section is appropriately defined by a maker, who likens it to a “dog’s hind leg.” Some makers shape the brick like a curved scallop-shell, inclining forward at the top; the effect is that as the heat ascends from the fire, it strikes or comes in contact with the projecting part, and rebounds or is deflected into the room; it is a similar action to that which takes place if an object, say a ball, is thrown upon a wall and comes in contact with a similar projection--it would bound off or be deflected.

It would be impossible to describe all the existing improvements upon the ordinary or old form of open-fire stove (commonly known as a “register grate”), but the following are some that are tolerably well known and have a good share of favour.

“The Abbotsford Slow-combustion Grate” (Mappin and Webb, Cheapside, London), which has now been used some years, was about the first recognised form of stove that had the bottom closed, so that the supply of air for combustion is carried through the front only. This is a great improvement (as explained by the economiser), by lessening the consumption of fuel without decreasing the efficiency or its heat-giving properties. The bottom of the fireplace is a solid fire-brick slab, and the chief property of this stove is truly named “slow combustion.” Many people have tried to apply this advantage to existing stoves by having a piece of iron cut to lie _upon_ the bottom grate; but iron is too rapid a conductor, and failure is experienced by having the lower part of the fire dull and dead. It cannot, however, be said that a solid bottom is the best, for it permits of accumulation of ash, and it is slow lighting.

“The Wharncliffe Patent Warming and Ventilating Grate” (Steel and Garland, 18 Charterhouse Street, London, E.C.) Fig. 34, is an excellent form of grate, and is fixed back against the wall, wholly projecting into the room, an air-chamber surrounding the fire-box; this air-chamber is, whenever convenient, connected with the outer air by means of a pipe, and within the chamber gills or ribs are provided, attached to the fire-box (the principle and advantages of these gills or ribs, which are to increase the heat-giving surface and to prevent over-heating of air, will be explained under Gill stoves).

When the fire is established, the metal of the fire-box becomes heated, which then heats the air contained in the air-chamber, rendering it lighter, whereupon it rises and flows out into the room through the perforations provided in the pattern of the ironwork; cold air immediately flows in to take its place, which is then heated, and passes out, so that as its name implies it is a ventilating as well as warming grate, and has the further advantage of the cheerful open radiating fire; but it must be remembered that with ventilating stoves there must be provision made for the removal of vitiated air, which in this case is taken up the chimney along with the products of combustion.

Another improved form of warming and ventilating grate is that invented by and named after Captain Douglas Galton (makers, Yates, Hayward & Co., Upper Thames Street, London). The principle advocated in this instance is contrary to that generally adopted, insomuch that the warmed fresh air is admitted into the room near the ceiling, and the abstraction of vitiated air is performed through the grate by the chimney draught. This is an open-fire grate fitted within a mantel in the usual way, and is provided with an air-chamber at the back, and which is connected with the outer air as before explained. From this air-chamber a perpendicular shaft or flue is carried, terminating by being turned into the room with an inlet grating or louvre. As before explained, the air within the air-chamber is warmed, and rises and passes into the room close to the ceiling; from there it is drawn down towards the fire, and eventually passes up the chimney, so that there is always a current of warm fresh air from the ceiling downwards. There are as many advocates for this down-current system as for the up current, as in the Wharncliffe and others. The Captain Galton has had about 14 years’ trial, and is still largely used. A rather peculiar and advantageous action takes place, by the fact that the apartment becomes fully charged with fresh air and the supply for combustion and draught is not drawn from the crevices beneath doors, &c., so that when a door is opened no inrush of cold air is experienced. This and the Manchester grate can most conveniently be used for warming another apartment also from the same fire.

“The Nautilus Grate” (Jas. B. Petter & Co., Yeovil), Figs. 35 and 36, is, as the name signifies, shell-shaped. The products of combustion rise from the fire, and after revolving within the centre or axis pass off by two concealed flues at the back of the grate to a flue prepared in the back of the fireplace; the ashes fall through a small grating into a closed ash pan. The warmth radiated direct from the cheerful open fire and indirectly from the outer case is considerable, and the results are very satisfactory, as no heat is lost by conduction. This grate is also cleanly, economical, and portable. The back, cheeks, and hearth should be tiled; the extra expense is fully compensated for by the handsome appearance.

The “Ingle Nook,” Wright’s Patent (GEORGE WRIGHT & SONS, 113 Queen Victoria Street, E.C.), Fig. 38, is a combination of all the most recent improvements, with two new features never before introduced into this class of grate, viz. the regulation of draught by means of an ordinary damper, and the complete independence of the actual working part of the stove, so that it may be removed at any time for repairs without disturbing the outer casing or brickwork.

_Special features and advantages_.

Radiation and complete utilisation of the heat generated from all parts of the grate, as not only the heat given off from front of fire, but also all heat radiated from sides and back of grate, which is usually absorbed in brickwork, is here passed into warm-air chambers and thence into the room. Economy of fuel, with increase of heating power. Prevention of down-draught, and partial consumption of smoke. Simplicity of construction and fixing, so that easy access is afforded to all parts of the grate, more especially those likely to want renewing. Pleasing appearance of the ordinary open fire, with heating power of a warm-air stove. This stove being complete in itself can be fixed by any ordinary workman without removing the mantel-piece or in any way interfering with the decorations of the room. The whole construction and principle of the grate are so simple that they can be readily understood by reference to the plan and section annexed. The interior portion of fire-box is of fire-brick, and can readily be removed from the front without disturbing any other portion of the grate. The back leans forward, deflecting the radiant heat into the room, and contracts the throat of the flue so as to quicken the draught directly the fire is lighted, which flue then expands and is again contracted at the top by means of the damper. Less than half the quantity of fuel is required to warm any given space, and more than double the quantity of heat is given off than from an ordinary grate with the usual supply of fuel. By introducing a fresh-air flue where practicable the perfection of ventilation may be obtained. The cost does not greatly exceed that of an ordinary grate, and is very much below that of any other grate of this description at present in the market. _See advertisement in front of title page._

“The Rumford-Teale Grate” (made by Verity Bros., 98 High Holborn, London), is made nearly wholly of fire-brick, upon strictly scientific principles, as the name indicates. There is very little iron in its construction, the front being a steel wire trellis instead of bars; this permits free radiation from the front and reduces loss by conduction. This front, apparently fragile, lasts for a considerable time (4 or 5 years), and is easily replaced by any one at an extremely small cost.

An improvement upon the Rumford-Teale grate is the “Eclat,” by the same makers, shown in elevation and section in Fig. 39. Its distinguishing features are a double flue (one for quick and the other for slow draught), and the projection of the fire in advance of the chimney breast. The figure shows: A, damper for regulating combustion; B, perforated fire-clay back; C, tiles to taste; D, economiser; E, ashpit; F, chimney breast; G, frieze; H, removable bottom grate with fine mesh; J, valve for regulating combustion.

There are several forms of combined open- and close-fire stoves, which stand independent of any brickwork, and are generally known as “American stoves.” These stoves are good heat givers, ornamental, and have several advantages, and can be obtained at almost any hardware stores; they do not work upon strictly hygienic principles, as they are apt to get overheated when closed, and render the air unpleasantly dry; but this can be remedied to some extent by using a vaporising pan, as will be explained later on.

There is another form of open-fire grate that should be mentioned, viz. those that have the fire replenished by placing the fresh fuel underneath, and are known as underfed smokeless grates. This idea, which deserves high commendation, has been rendered practical, but cannot be said to be perfected yet. It originated in Dr. Arnott’s stove, which was made with the usual set of front bars fixed about 12 in. high from the hearth, and the space under the bars closed in front. The bottom of the fire, which is movable, is lowered down to the hearth and the space filled with coal: the fire is laid, and ignited on the top of this store of fuel. As the fire burns down, the bottom grating is raised by means of a lever bringing fresh fuel within the fire-basket, and this bottom is raised as often as the fire burns down; it will be seen that the gaseous products given off by the fresh fuel must pass through the incandescent fire, and so be perfectly consumed, and the space below the front bars is sufficiently large to hold fuel for one day’s consumption.

“The Kensington Smoke-consuming Grate” (Brown and Green, Finsbury Pavement, London) is an underfed grate, and has received high commendation from good authorities; it has not the complication of Dr. Arnott’s, and is of good appearance, being fixed in a similar manner to any ordinary grate.

“Hollands’ Patent Underfed Grate” (Hollands & Co., Stoke Newington) is a still further improvement, and, except for a little complication in construction, may be considered the best in action and results. The advantages of underfed grates are, firstly, an abatement of the smoke nuisance, full utilisation of the fuel, and more powerful radiation from the top of fire, which is always incandescent. There is commonly no provision made for the supply of air for combustion, nor to replace that which is taken from the apartment by the draught in the chimney--the cracks and fissures around doors and windows sufficing for this purpose, is the too commonly general idea; but for perfection in warming upon hygienic principles, there must be a proper supply from external sources; but this will be more fully treated under Ventilation; it will, however, be noticed that some of the ventilating stoves make provision for this in themselves; this particularly applies to Captain Galton’s principle.

_Close-Fire stoves._--The old form of close-fire warming and ventilating stove is that known as the “Cockle.” It consists of a closed circular fire-box with a dome top and a similar shaped outer casing; between the fire-box and the casing is a space of a few inches all round, known as the air-chamber, which by means of a pipe is connected with the outer air. The action is similar to a flue; the air within the air-chamber, being in contact with the heated surface of the fire-box is warmed, and rises and flows out at the top through an aperture provided at the top (as explained with the Wharncliffe grate), or it is made with a nozzle at top to attach a pipe and carry the warm air wherever required, so making it a hot-air furnace, in which case it would be fixed in a basement or cellar as at the best it is not ornamental, but this primitive form of stove has gone somewhat into disuse.

Where a continual genial warmth is required at little cost in an apartment, the slow-combustion stove, such as that made by the Thames Bank Iron Company, London, (Fig. 40), may be employed. The external air is drawn in by a smoke-pipe channel and impelled through orifices in the stove. The smoke can be made to pass out at any level in the stove that may be found most convenient, but unless there is a high chimney shaft 25 to 30 ft., an underground flue connection is not recommended. The fuel, consisting of coke or cinders broken small, is supplied at the top, the ashes or cinders being removed through a sliding door at the base; a special soot-door is provided for clearing the flue before lighting the fire.

This appears an appropriate moment to mention that additional results can be obtained from close-fire stoves, by carrying the smoke flue down, and just below the floor level, in a properly made channel, and covered by a grating, as with hot-water pipes. It is known that a good proportion of the heat must be carried away by the flue, so that by this means nearly the whole of the heat evolved by combustion can be utilised; but it is necessary to bear in mind that the Building Act prescribes that no hot-air or smoke-pipe shall be nearer than 9 in. from any woodwork or inflammable material, and it is necessary that the main flue be high, as a good draught is needed to withdraw this nearly cold smoke or vapour, and in many instances where the under-floor horizontal flue is of good length, a pilot stove or rarifier is necessary at the foot of the main up-flue to keep up the draught, but in most cases the rarifier is only needed at first lighting. This arrangement is rarely applicable in dwelling-houses.

Improved forms of close-fire stoves are as multitudinous as improvements in open-fire grates; they are made either wholly closed, generally called “slow-combustion stoves,” and are arranged to burn many hours without feeding; or, as convertible open and closed; the latter have the advantage of the cheerful radiating fire when open.

“The Tortoise Slow-combustion Stove” (makers, Portway and Son, Halstead, Essex) is finding a ready sale and considerable favour, as maybe judged by the fact of its being obtainable at nearly any ironmonger’s. This stove, as with the majority of slow-combustion stoves, consists of an ornamental outer casing (cylindrical, square, or hexagonal), the height being about 2½ times the diameter; this casing is lined with fire-brick, and constitutes the fire-box; there is an ash-box and door below, in which is fitted a ventilator or damper to regulate the draught and speed of combustion. The fuel is supplied through a door provided at the top, and the smoke outlet is also placed near the top. In use, the fire-box is filled with coke and cinders, and the draught is regulated by the ventilator; it will then burn, and heat an apartment for many hours without attention. It is a very useful form of stove for greenhouses (in which case it would be fitted with a vaporising pan), halls, offices, &c., but hardly suited for living-rooms; the fire-brick lining tempers the heat, but if in use where children or dresses would come in contact, a guard must be provided. Slow-combustion stoves are made in a variety of forms, and the effect is very pleasing when externally fitted with tiled panels, &c.

For slow-combustion stoves that are required to burn for a longer than usual period without attention a chamber or hopper is fitted on top to take a further charge of fuel; it is taper-sided and open at the bottom, very much like an inverted pail, but about 2½ ft. high. It will be readily understood that as the coke is consumed, the upper supply gradually sinks down until the whole is consumed; this would utterly fail with a fuel that cakes, such as soft or bituminous coal.

“Musgrave’s Patent Warming and Ventilating Stove,” Fig. 41 (Musgrave & Co., Limited, 97 New Bond Street, London), is made upon the slow-combustion principle, to burn from 8 to 24 hours, but is much more highly finished than the last named, and is constructed in so many patterns and sizes as to be suitable for almost every purpose, from small dwellings to the largest buildings. The stove consists of an outer casing, within which is contained the fire-box and an air-chamber. The latter is provided with gills to increase the heating surface (see Gill stoves). The smoke and heat when leaving the top of the fire-box is carried down a flue-way to the bottom of the stove, and then up to the top again into the smoke-pipe; this flue-way is within the air-chamber, and so utilises the major portion of the heat passed into the flue; the fuel to be used is coke, which is the most suitable fuel for all slow-combustion stoves.

For conservatories or where the air requires moistening these stoves are very neatly and effectually fitted with vaporising pans; and these stoves are also made to act as hot-air furnaces, and in combination with hot-water-pipe heating apparatus.

Roberts’ patent terra-cotta stoves operate also by slow combustion and are self-acting, but possess the additional advantage of purifying and radiating the heat by the terra-cotta, which is contained between 2 concentric cylinders of sheet iron united at the base and top, the outer cylinder being perforated to allow of direct radiation of heat from the terra-cotta. The stove consists of 4 separate parts, namely, the stove body, its top or cover, the fire-box, which can be lifted in and out, and the stand, with draw and damper. The fire is lighted at the top and burns downwards, the air sustaining it being drawn upwards through the bottom of the fire-box and thence through the fuel. The stove can be placed in any position on an iron or stone base and connected with the nearest chimney flue by an iron pipe provided with soot-door elbows, care being taken to form a complete connection by abandoning any other open fire-grate in the room and screening it off by an iron or zinc plate. They emit no effluvium, as the terra-cotta gradually and completely absorbs all the caloric in its permeation through the shell before it is communicated to the outer air, which is thus warmed and diffused in a healthy condition over the room. The top of the stove is movable, so that the fire-box can be removed to be cleaned and recharged without moving the stove body, and a sand groove is inserted at the top where the cover rests, which is filled with fine dry sand to prevent any escape of smoke.

Close-fire stoves, consisting of a strong iron fire-box, on to the outside of which is cast a series of vertical, parallel plates or ribs, are known as “Gill” stoves, as the plates or ribs referred to somewhat resemble the gills of a fish. These stoves are provided with a door for replenishing the fire, with ash-pan and ventilator below, and the iron base upon which the stove stands is made hollow, and has a series of holes or perforations opening between the gills, and provision is made for connecting the base with the outer air whenever convenient. It must now be explained that the object of the gills is to extend the heat-giving surface of the stove. It is known that iron is a very rapid conductor of heat, and consequently when the iron of the fire-box becomes heated, the heat is as quickly transferred to and felt at the extremities of the gills. It will be readily understood that only a certain amount of heat is given off by the fire, and the greater amount of metal it is transferred to, the lower must be its temperature; this is the chief and real advantage, as instead of a small volume of air being heated to a very high temperature, off a plane surface that would possibly get red hot, there is a larger volume of air at a lower temperature, and this has the further decided advantage that the air does not become unpleasantly dry, and the particles of dust, &c., in the air do not get scorched and burnt, and cause the unpleasantness commonly known as “burning the air.”

A further advantage possessed by these stoves is that they are not so much a source of danger, as the size of the gills is so proportioned to the size of the fire-box, that in ordinary use they cannot become excessively hot, and this is especially desirable where children or ladies’ dresses, &c., might come in contact.

These stoves can be obtained at any ironmonger’s or stove maker’s. A good form is that made by the London Warming and Ventilating Co., 14 Great Winchester Street, London, and is called the “Gurney” stove (Fig. 42). This is circular or cylindrical in form, with a dome top, and the gills, which are perpendicular, extend around the stove. A novel feature with this stove is that it is provided with a water-pan or trough carried round the base of the gills; when this pan is charged, the lower ends of the gills are immersed, and the heat that is conducted there causes the water to slowly evaporate. The advantage of a vaporising pan is this: before being warmed by an ordinary stove, fresh air holds a certain and proper amount of moisture, but as it becomes heated by such a stove the temperature is raised without proportionately increasing the moisture, and this is apt to make it unpleasantly dry, particularly to those suffering from asthma or any bronchial affection. The reverse is the case when the air becomes heated naturally (except when the wind is in the east); the proper proportion of moisture increases as the temperature rises; for instance, the atmosphere at 80° F. would contain about four times as much moisture as when at 32° F. The principle of the Gurney stove is such that the _natural_ degree of moisture is always maintained in the heated air. The greater proportion of modern close fire-stoves and furnaces have gills applied in some form or other.

It might be mentioned that 13 Gurney stoves have effectually coped with the problem “How to heat St. Paul’s.”