Heating apparatus

“ Gas stoves are becoming increasingly popular by reason of the ease with which they can be put in action and made to maintain an even temperature. But the most up-to-date heating apparatus is undoubtedly electrical. Utensils of all sorts are fitted with very thin heating strips (formed by the deposition of precious metals, such as gold, platinum, &c., on exceedingly thin mica sheets) , through which are passed powerful currents from the mains. ”

“ To regulate the heat it is necessary either to instal a number of small radiators or to divide the radiators into sections, each section controlled by distinct valves; steam may then be admitted to all the sections of the radiator or to any less number of sections as desired. In a hot-water system the heat is given off at a lower temperature and is consequently more agreeable than that yielded by a steam-heating apparatus. The joint most commonly used for hot-water pipes is termed the “rust” joint, which is cheap to make, but unfortunately is inefficient. ”

“ It must not be concealed, however, that to manage a gas-heating apparatus requires some amount of experience, and those who would succeed must habituate themselves to observation, not only of the action of the apparatus, but of its influence on the temperature of the house at different hours and in different states of the weather. ”

“ In a dwelling house, properly constructed, the entire heating apparatus is a hot air furnace, with a cold air box connected with outdoors constantly bringing in a fresh supply of pure air to be heated. If it were possible this would be the ideal way of supplying the heat to the hover, but of course in a long Brooder House it is impossible to do this. ”

“ Should a defect occur with a wrought iron boiler it is usually necessary for the purpose of repair to disconnect and remove the whole apparatus, the heating system of which it forms a part being in the meantime useless. In a type built with vertical sections each division is complete in itself, and is not directly connected with the next section, but communicates with flow and return drums. ”

“ There are a number of methods available for adoption in the heating of buildings, but it is a matter of considerable difficulty to suit the method of warming to the class of building to be warmed. Heating may be effected by one of the following systems, or installations may be so arranged as to combine the advantages of more than one method: open fires, closed stoves, hot-air apparatus, hot water circulating in pipes at low or at high pressure, or steam at high or low pressure. ”

“ Heating by warmed air, one of the oldest methods in use, has been much improved by attention to the construction of the apparatus, and if properly installed will give as good effects as it is possible to obtain. The system is especially suitable for churches, assembly halls and Warm air. large rooms. A stove of special design is placed in a chamber in the basement or cellar, and cold fresh air is passed through it, and led by means of flues to the various apartments for distribution by means of easily regulated inlet valves. ”

“ With the ordinary form of welding it is necessary to drive the heated parts together without any delay, and at the least cooling must be reheated, or the joint will not be perfect.
The smallest kinds of electric heating apparatus are now being made, so that small articles, sheet metal, small rods, and like parts can be united with the greatest facility.
p. 184
CHAPTER XVIIIToC X-RAY, RADIUM, AND THE LIKE
The camera sees things invisible to the human eye. ”

“ Conduction of heat is a commonplace occurrence in our daily lives, in industrial processes, and in nature. If a metal spoon is dipped in a cup of hot coffee, the spoon handle soon becomes warm and then hot—some of the heat in the coffee is conducted along the spoon. Heat from a burner on a stove is conducted through the bottom of utensils to cook food. In a steam engine or hot-water heating system, heat from burning fuel is transferred by conduction through the iron or steel of the boiler to heat water. ”

“ Heaters are almost universally used in connection with steam fire engines to keep the water hot, and in many cases to keep a few pounds pressure to shorten the time of going to work should the fire be close at hand. This boiler has an advantage for this kind of heating; the circulation is so perfect and free that all the water in it is heated alike ”

“ Must be heated, where artificial heating is necessary to prevent freezing, by steam or hot-water systems, the heater to be located in a separate building, and no open flames to be permitted within generator enclosures. ”

“ Heating Unit. The heating unit of a hot-water system is like any stove consisting of a fire pot and grate. Some are adjustable so that different kinds of fuel may be [66] used. A gas burner is sometimes placed in the fire pot and used for heating a furnace, but this is one of the most wasteful ways of using gas. A real gas furnace is much more economical. The fire and heat from the fire circulate around the coils containing the water. If the coils are not constantly kept full of water, they will be injured by the heat. ”

“ Like any other device for heating, the perfect and satisfactory results depend altogether on the manner of setting them. In no case should a heater be expected to develop its full power when placed in a fire-place in so close proximity with the brick as to allow the hot air to strike against and be absorbed by them. The heater should be enclosed in a jacket of sheet-iron, having an 8-inch opening, and a collar at the top. Attached to the collar, and “built in” the chimney, should be an 8-inch tin pipe, connecting with the register-box in the second story. ”

“ The heatilator is a built-in recirculating steel unit consisting of metal sides and back to form a heating chamber, adjacent to the fire pit, which draws cold air through a register at each side near the floor and after the air is heated ejects it through similar registers above. ”

“ Heating the metal by direct contact from within the metal itself by these heaters, makes a very efficient equipment, as all of the heat generated is immediately transmitted to the metal exactly where it is required, and there is no loss of heat due to faulty conduction. The dynamic thermometer bulb being immersed in the metal adjacent to the heaters and the pump-well, permits of a very close temperature regulation. ”

“ In buildings of the second class, such as residences, office buildings and hotels, we have been, as a rule, satisfied with sufficient heat, and have relied upon such ventilation as is secured by the natural circulation methods. In such buildings, therefore, the system of heating most used is that known as "direct radiation," in which radiators, or some form of radiating surface, are located in each room, and connected by an arrangement of piping to a central source of steam or hot-water supply. ”

“ This rule when applied to a boiler with a well-designed furnace, stack and setting should be very conservative. It is much better to estimate the steam consumption of the entire plant (see Chapter V., page 60 for steam consumption of radiation) and calculate the boiler requirements according to the rules of boiler design. The designs of the cast-iron heating boilers are innumerable and can only be selected by the careful judgment of the engineer. ”

“ Some firms have now made percolators and water heaters with fuse-nut or safety fuse devices which melt if overloaded or allowed to heat up without any liquid in them to be heated. You must not let a percolator “perc” without any water in it. People complain more about good percolators because their heating element [11] burns out, either because they do this or because they have it connected up with too many other devices. Even if you do the right thing in these respects, don’t forget to disconnect the electricity by pulling out the plug. ”

“ The question of practical efficiency is, therefore, more strictly speaking, only one of effectiveness of surface. That is, of two radiators under exactly the same conditions of temperature and surroundings, that one which has such an arrangement of its surfaces as to give out the most heat per square foot is the most effective, usually called the most efficient. In all tests of radiators, the heat given off is measured by connecting them so that the steam which condenses can be accurately weighed, its pressure, quality and temperature being determined at the same time. ”

“ As soon as the bricks have become red hot, the current is diverted to an adjacent chamber or pair of chambers, and the acquired heat is removed by a current of cool gas or air passing towards the furnace, where it arrives at a temperature sufficiently high to ensure the greatest possible heating effect in combustion. ”

“ The efficiency of an electric stove or electric iron, or, in fact, any electrically heated device, may be determined in a manner similar to the water heater. In the case of a stove, place a vessel filled with water on it and measure the heat imparted to the water in a given time, also the input to the heating element in the same time, from which data the efficiency may be calculated. ”

“ The chief points to be considered are efficiency of heating surface and capacity of grate in proportion to surface, strength of parts, tightness of joints, ease of cleaning and effectiveness of circulation—there should be no "dead ends" where the water is not kept in circulation by the heat of the fire. ”

“ When feed water is taken from the hot well, it will save 7 to 8 per cent.
Where all the steam generated by a boiler is used in the engine and the exhaust passed through a heater it is found by actual experiment, where iron tubes are used in the heater, that approximately ten square feet of heating surface will be required for each 30 lbs. of water supplied to the boiler at a temperature of 200 degrees Fahr. ”

“ In many mills and factories which use condensing engines, and in which, consequently, exhaust steam is not readily available for heating, steam for this purpose is taken direct from the boilers through a reducing pressure valve and used in the heating system at a pressure of 5 to 20 pounds per square inch. ”

“ Desirable qualities are that the arrangements of the furnaces should be such that a reasonably perfect combustion of the fuel should be possible, and that the heating surfaces should be capable of transmitting a large proportion of the heat produced to the water so as to obtain a high evaporative efficiency. Further, the design generally should be compact, not too heavy or costly, and such that the cleaning necessary to maintain the evaporative efficiency can be easily effected. ”

“ It does not necessarily require all the exhaust steam—or the whole volume of waste steam passing from the engine to bring the feed water up to the temperature desired, and the larger the heating appliance the smaller proportion is needed—hence heaters are best made with two exits nicely proportioned to avoid back pressure and at the same time utilize enough of the exhaust to heat the feed water. ”

“ As the heat is applied to the inside of the furnace and tubes, it must, therefore, be the inside dimensions which determine the amount of heating surface.
Note.—If we multiply the interior surface of a tube by the intensity of heat applied, and divide the product by the exterior surface, we shall have the intensity at the outside. We also apply more heat to the outside of a tube, which, passing to the inner surface, augments in intensity per unit of area.
The area of the inner fire-box is not all available for heating, but requires to be reduced as follows:—
For the fire-door. ”

“ If the proportion of free oxygen (i.e. excess of air) is large, more air is passed through the furnace than is required for complete combustion, and the heating of this excess is clearly a waste of heat. The position of the econometer in testing should be as near the furnace as possible, as there may be considerable air leakage through the brickwork of the flues.
The air supply to modern furnaces is usually delivered hot, the inlet air being first passed through an air-heater the temperature of which is maintained by the waste gases in the main flue. ”

“ Heat loss in buildings.—There have been considered in previous chapters the various kinds of radiators in use and the amount of heat given off by them under different conditions; and the subject now approaches a study of the particular way in which the heat is utilized. The object of any heating system is, of course, to maintain a uniform temperature in the building in question, and to do this it is necessary: First, to replace the heat lost by convection and radiation from the windows and walls of the building to the colder surroundings outside ”

“ The stream of air is usually accomplished by the use of ordinary chimney draft assisted by the warm products of heating from the heater. The hot air products of combustion pass through a tapered nozzle into the moist air exhaust pipe, and by the speed a suction is created which helps to pull the moist air out of the cabinet and up the chimney.
When you buy a dryer see to it that the exhaust pipe is large so that you will have wind and heat instead of just heat. Air circulation is what you are really buying. ”

“ An electric heater comprising a receptacle, containing oil having a high flashing point and means for circulating the same, a resistance conductor immersed in the oil and adapted to heat the same, and a heating system partially within the container and arranged to receive its heat from the circulating oil. ”