41. Musgrave’s Stove.
“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.”