Fan (machine)

“ The column of air being thus less distorted in its progress, there is not only a greater quantity discharged, but much less power is consumed in effecting that discharge—in the common fan it{68} is evident, from the circumstance of the air flowing to an apex, that a great amount of power is wasted in producing the increased velocity with which a column of air equal in volume to the two ingress openings of the fan must pass so contracted an area before it is discharged; hence it is that the fan, as an air-moving machine, has been considered unequal to the screw. ”

“ In the stationary as well as in the portable vacuum cleaners the suction is caused by the pump or fan type machine. Some manufacturers advocate one, some another. In picking your winner you must go to the best manufacturer of each type and let him give you his tale, and then see whether you come out a pump fan or a fan fan!
The other intricacies of this simple machine need not bother you. Go to the best makers and make them responsible for your purchase. Not all of us being engineers, you have to depend on the reputation of the best makers. ”

“ The whole of the fan is made by machinery! An [Pg 390] amazing machine cuts out each layer of paper of the proper size and shape, and when all the parts are ready, sticks them neatly together. Most Japanese toys—which really are Japanese, not mere imitations of Japanese designs—are made by hand ”

“ Link Belt Machinery Co.‘s Shop, Chicago, showing Sturtevant ventilating and heating apparatus.
In large machine shops a heating system is finding favor which equally departs from traditional methods. In a small workshop piping filled with steam or hot water serves well enough: in a [381] lofty machine shop it serves badly, sending as it does warm currents of air toward the roof where warmth does only harm. The union of a fan with a system of steam coils introduces a vast improvement. ”

“ As the inward current of air rushes in at the circular openings on each side of the Fan-case, and would thus oppose each other if there was a free communication between them, this is effectually obviated by forming the rotating portion of the fan by a disc of iron plate, which prevents the opposite in-rushing currents from interfering with each other, and at the same time supplies a most substantial means of fastening the blades, as they are conveniently riveted to this central disc. ”

“ Some of the motors are self cooled which also does away with wear and hot boxes.
There are various kinds of fans which may be used. Those which change their direction in process of revolution are good. Some think they are better than the one-direction fan, and maybe, where the fan is used alone without other attachments such as purifiers and blowers, this style may be more efficient. ”

“ The proper cooling of the cylinders has been made an easier matter than formerly by the introduction of fans which direct a stream of cold air on to the cylinder head. Professor H. L. Callendar has shown in a series of experiments that a fan, which absorbs only 2 to 3 per cent. of an engine's power, will increase the engine's efficiency immensely when a low gear is being used for hill climbing, and the rate of motion through the air has fallen below that requisite to carry off the surplus heat of the motor. ”

“ When the coil is set to work, the molecules of the air are rhythmically attracted and repelled. As the force with which they are repelled is greater than that with which they are attracted, it results that there is a repulsion exerted on the surfaces of the fan. If the fan were made simply of a metal sheet, the repulsion would be equal on the opposite sides, and would produce no effect. ”

“ Many and manifold are the uses of the fan. What device, for example, could better display the beauty of a rounded arm, or the ivory whiteness of tapered fingers? Such an instrument provides graceful and often much-needed employment to those same delicate fingers; it supplies that necessary sense of completeness to the tout ensemble of the picture. And the comedy actress, desiring some trifle to emphasise a movement, to give point and expression to some particular action—what more effective instrument than a fan, the use of which, on the stage, has almost been elevated into a fine art! ”

“ The principle of the fan is very similar to that of the centrifugal water pump—vanes rotating in a case open at the centre, through which the air enters, to be flung by the blades against the sides of the case and driven out of an opening in its circumference. ”

“ A current of electricity is passed through a filament, such as we see in the incandescent lamp of a house electric light, and at once the heat sets the gun off as effectively as if a spark had ignited the powder. Then there is the aerophone, or fog-indicator, which points out the exact direction of some noise-making object by cutting the sound-wave in two, so as to send it first in one ear and then the other of the man who operates the invention, until finally he gets it in equal volume in both ears, and the dial on the machine points straight to the object which cannot be seen. ”

“ Lacquered tea-trays assume the shape of the fan; inkstands take the form of a closed fan, the ink-well at the rivet end, the body of the fan forming a case for pens;61 while in diapered patterns, borders, and other decoration, both flat and in relief, the fan motif is constantly made use of. The interesting series of fan-shaped panels illustrative of Japanese history, by an unknown artist of the Yamato Tosa school, seventeenth century, British Museum, 305-324, are excellent instances of the use of the fan form in flat decoration, these being probably removed from an old screen. ”

“ The machine consists of two sets of fans, enclosed by iron framing, driven by motor attached or by existing motive power, some four to six reams of paper being suspended in ball clip frames in the space between the two sets of fans. The air of the machine-room is circulated by the fans rapidly through the paper, and maturing takes place in two or three hours. ”

“ The armature is so constructed that there are air-passages running all through it, and on top of the revolving hood are two bonnet-shaped air-tubes set in such a way as to force the air down through the armature, which carries off [Pg 194] the heat and warms the power-house, on the principle of a hot-air furnace. This great machine—which, in a way, is so simple in its construction—when in action conveys to the mind of the beholder a sense of wonderful power. ”

“ At the same time the air which has been forced towards the outside of the casing and given a rotary motion is expelled from the opening at D (fig. 8) . All blowing fans work on the same principle, though differences in detail are adopted by different makers to meet the variety of conditions under which they are to be used. Where the fan is to be employed for producing a delivery or blast of air the opening D is connected to an air pipe which serves to transmit the current of air, and C is left open to the atmosphere ”

“ These anti-gas fans, or flapper fans as they were called, are made of canvas supported by braces of cane and attached to a hickory handle about two feet long. The blade of the fan, which looks like an immense fly swat, is hinged in two places and measures about fifteen inches square. When the fan is brought down on the ground it bends over on the back hinge and produces a sharp puff of air, in just the same way that the sudden shutting of an open book does. ”

“ Roll-up fans (Maki uchiwa) are circular, the paper stiffened with thin strips of bamboo; the handle is of bamboo cut through with a slit to allow the circular fan, which is set on a pivot, to have free play. When open, the strips of the bamboo foundation are horizontal, thus securing rigidity; when not in use, the position of the strips may be reversed, and the disc rolled round the stick and tied.
Of modern fans, those of ivory and tortoise-shell, carved or decorated with lacquer and inlay, are, for the most part, made for exportation, and are often of extreme beauty. ”

“ Some are encased, others are open and fitted by means of annular frames in the ducts according to the intended effect and kind of fan. Fans are of two kinds, propeller and centrifugal, and, according to the pressure they exert, of low, medium, or high pressure. They are now often driven electrically, in which case there is advantage in coupling them directly with the motor.
Propeller fans have curved screw-shaped blades and are set at right angles in the duct upon the column of air in which they act by suction. ”

“ Two illustrations show a Sturtevant ventilating fan-wheel, without its casing, and a Monogram exhauster and solid base heater, as used in many modern installations. The net gain in sending warmed air just where it does most good is comparable with the profit in mechanical draft for a furnace as compared with natural draft. Either live or exhaust steam may be used in the heating coils through which the air is forced by the fan. ”

“ Previous arrangements having been made, it will be well, to avoid accidents, for No. 2 to partially inflate the balloon by a fan. Were this precaution not taken, it might happen that flame driven against the tissue-paper might set it on fire. Those who have not tried the experiment little know what power there is in a fan to set up and keep going a current of air. Sometimes people revive a sluggish fire by hanging a sheet of paper in front of it, but a far better application of the paper is to squeeze it into a rough fan and begin fanning. ”

“ Where a fan installation is necessary, the loss of draft in the fan connections should be considered, and in figuring conservatively it should be remembered that a fan of ample size may be run as economically as a smaller fan, whereas the smaller fan, if overloaded, is operated with a large loss in efficiency. In practically any installation where low temperature gas requires a fan to give the proper heat transfer from the gases, the cost of the fan and of the energy to drive it will be more than offset by the added power from the boiler secured by its use. ”

“ In the instrument-room the bands are connected with ordinary steam machinery, by which they are drawn in regular order with the utmost rapidity between the charged poles of an electrical machine in such a manner that, during the moment of each pin’s passing, it forms electrical communication between the instrument and the telegraph, and a signal is transmitted to the other end of the wire, where the spark perforates a paper and records the message. ”

“ In the ordinary fan, if a smoking match is applied to any part of the indraught opening, the air will be seen to flow towards a neutral point in the centre of the fan, following a spiral direction, and thence in the periphery of the fan.
In Mr. Clerihew’s modification of the blade each film of air, so to speak, flows into the fan directly, until it impinges on the curvilinear part of the blade, and from that point is thrown at a right angle towards the periphery. ”

“ As the air enters at the center of the fan and escapes at the circumference, it will be seen that its motion is changed while in the fan through a right angle. It may also be taken for granted that within certain limits the air has no motion in a radial direction when it first comes in contact with a fan blade. It is well understood that, unless power is to be wasted, motion should be gradually imparted to any body to be moved. Consequently, the shape of the blades ought to be such as will impart motion at first slowly and afterward in a rapidly increasing ratio to the air. ”

“ The excess of labor thus thrown upon my arm has its exact equivalent in the electric currents generated, and the heat produced by their subsidence in the coil of the armature. A portion of this heat may be rendered visible by connecting the two ends of the coil with a thin platinum wire. When the handle of the machine is rapidly turned the wire glows, first with a red heat, then with a white heat, and finally with the heat of fusion. The moment the wire melts the circuit round the armature is broken, an instant relief from the labor thrown upon the arm being the consequence. ”

“ We introduced a system by which the man at the furnace has nothing at all to do with the heat. He does not see the pyrometer--the instrument which registers the temperature. Coloured electric lights give him his signals.
None of our machines is ever built haphazardly. The idea is investigated in detail before a move is made. Sometimes wooden models are constructed or again the parts are drawn to full size on a blackboard. We are not bound by precedent but we leave nothing to luck, and we have yet to build a machine that will not do the work for which it was designed. ”

“ A small opera- or spy-glass was set in the chief sticks of the fan, either at the top of the panache, probably the earliest form, or at the rivet. In the former case the whole of the blades were perforated, the fan when opened showing a series of circular perforations round its upper border. The advantage of such an arrangement will be obvious; a fair reveller might see without being seen, and the tell-tale blush be hid. For more distant objects the opera-glass was called into requisition, the fan used either open or closed. ”

“ Fig. 97. A HIGH FREQUENCY MACHINE
Figure 97 shows a high frequency (violet ray) electric [163] machine designed by the author in which this idea is carried out. The stand is of iron, nickle-plated; the base of the apparatus proper is of wood, japanned black; the rim is of brass, nickle-plated; the plate-base, on which the visible part of the apparatus is mounted, is made of slate and japanned black; the metal parts of the interruptor are nickle-plated, and the coil and insulating standards are of hard rubber as is also the handle. ”