US1602008A - Air turbine - Google Patents

Description

c. F. GERMEYER AI R TURBINE Filed April 18. 1922 Oct. 5 1926.

INVENTOR AT ORNEY Patented a. 5, 1926.

UNITED STATES CHARLES FREDERIC GEBHEYEB, 01' NEW TQ'B. I. DUNKLE, CHARLES T. DUNKLE, BISBURG, PENNSYLVANIA.

CUMBERLAND, PBNNSYLVAN IA, ABSIGNOB AND CHARLES A. cams-as, ALL 0] BAD- AIB TURBINE.

Application fled April 18 This invention relates to blowers.

The principal object of the invention is to provide a blower of a type especially adapted for, though not limited to use 1n connection with, domestic heating plants to create a forced draft through the fuel bed, so that the lower and cheaper grades of coal may be efiiciently, easily and quietly. burned inordinary furnaces without any modification of their structure. Y

The steadily mounting prices of coal have made this item of expense to the average family a very serious one. Years ago the sizes of coal that we now call nut and pea, were considered waste at the mines, but improvements in burning apparatus have been made with the possibility of burning smaller and smaller coal until now it is found that many industrial establishments burnanth'racite coal almost as fine as sand. The cost of this coal, since it comes principally from culm banks and from the streams surrounding the anthracite coal regions, is much less than any prepared coal, and it is the purpose of this invention to extend the use of this coal with its attendant savings to domestic uses. The apparatus'disclosed in this application is the result of protracted and persistent efforts to satisfactorily solve the problem, and in its present form has been in successful operation long enough to establish its merit under various and adverse conditions.

In practice it has been demonstrated that two features, aside from mechanical reliability, are of prime importance. -These are efliciency, which is reflected in low cost ofpower, and quietnessof operation. Standard practice in blower construction has been departed from in order to secure these qualities to a marked degree.

In the accompanying drawing which forms a part of this specification and where-- in an illustrative embodiment of my inven-. tion is shown,

Figure 1 is a diagrammatic view showing aninstallation of a preferredtvpe of blower in connection with a conventional type of furnace, and also showing a means for regulating automatically the draft created by the blower;

Figure 2 is a section of the blower and it motor on the line 2-2 of Figure 1;

Figure 3 is a longitudinal cross section 1m. Serial No. 554.980.

- through the rotor and its casing showing parts broken away;

' Figure 4 is a transverse cross section through the same parts;

Figure 5 represents a series of sections of modified forms of blades;

Figure 6 is an enlarged detail view disclosing how the air inlet is formed.

Referring more specifically to the drawing, there is shown'a blower or fan casing .5, which preferably .is made up of two similar flat spaced walls 6 and a curved wall-7 joining the walls 6. It is preferred that the curved wall 7 have a refular and uniform curvature, such as that o a volute or spiral; and by way of example, the volute form is 'shown in Figures 1 and 3. For the admission of air into the casing, there are two apertures or inlet ports 8, one in each wall 6, disposed opposite each other and each being preferably circular. The centers of vthese inlet ports, in the embodiment of the invention illustrated in the drawing, coincide with a line drawn through the origin of the volute which determines the shape of wall 7. This line is the axis of the rotor which rotates in the casing. In other words, the preferred arrangement is to have the inlet ports at the origin of the volute and also coaxial with the rotor or fan, whose axis therefore coincides with the origin of the volute. As seen in Figure 4, the walls of the inlet ports 8 are rounded and tapered inwardly.

The casing has a discharge port 9 which is of rectangular cross section (Figure 2). The walls 6 and 7 are so disposed that" the casing proper likewise has a transverse rectangular cross section, as Figure 4 shows. By reason of this construction, the housing member or casing has an essentially spiral contour and is rectangular in section in order to'preserve the air as delivered by the rotor in individual fiat strata throughout its travel in the casing.

Mounted upon a drive shaft 10 in any desired manner is a fan or rotor. The rotor includes a circular or polygonal disk 11, a plurality of flat or curved blades 12, and two like annuli 13. The disk 11 is at right angles to the shaft 10 to which it is fixed, and carries the blades 12 uponits periphery, the blades being set in slots provided on the disk and being disposed radially of the disk.

The disk 11 is beveled or rounded from its center to its periphery, Where its edge is relatively thin (Figured), and the hub of the disk preferably has an air deflecting conical protuberance 14 on each face, whose axis coincides with the rotor axis and with thecenter line of the air inlets. These cones or protuberances extend outwardly from each disk face toward the air inlets 8. vhe blades 12 are preferably flat on both faces and have rounded longitudinal edges as seen in Figure 3, but their shape may be altered as disclosed in Figure 5. Their length'is less than the Width of the wall 7 of the easin'g. All the blades 12 are mounted at their ends in grooves provided in the inner faces of each'annulus 13, the width of the blades being nearly or quite equal to the width of the annuli. The disk .11. blades 12 and annuli 13 together provide a strong aud rigid but economical duplex fan structure.

The central openings 15 of each annulus have rounded walls. as shown in Figure 4-, and the curvature of these walls tapers in.- wardly and conforms as nearly as po.-=sible to the curvature of the walls of the openings 8 in the casing walls 6 and provides a hell shaped inlet. Now the central disk 11 is spaced from the two annuli and is preferably of smaller diameter than either, so that there is an air passage provided which allows free drawing in of the air into the casing from each side of the disk 11. The converging shape of the two respective air inlets, in conjunction with the air deflecting cones 14, are designed to offer as little resistance as possible to the incoming air currents and to prevent eddies. The annuli are each reduced in thickness from theircenters to their peripheries Fig. 4), where the edges are relatively thin, so that the two cur-' rents of air drawn in from each inlet meet beyond the disk 11 and expand to. the full width of the casing.

The rotor is made entirely ofwood, except the shaft and fastening means. The walls 6 are made of wood and the wall 7 is. formed of metal. It has been found that wood materially contributes to quietness of operation and there are other reasons why I believe that wood is the best material to use.

Figure 2 shows the preferred way in which my improved fan and easing may be supported. A motor 16 carries the moving parts of the fan upon its shaft 10, while the fan casing is independently supported by brackets 17 secured to the motor frame. This is a novel feature so far as I am aware, for the motor wholly supports the blower.

WVhile the blower is well adapted for many industrial applications, one way in which it may beeinployed to advantage is shown in Figure 1, where a furnace 18 is illustrated with the blower air current in the ash pit 19 of the furnace so that a forced draft up through the fuel bed 20 is created.

Figure- 1 also shows-an autmnatic control means for the blower so tl 1 g the forced draft created thereby may beafogulatedor stopped altogether .wheirthe are becoliies hotter than. necessary,- and will fbc' started again if the fire dies (l0\\'1l.- 'Ti li(3 electric conductors 21 two wires 'tlorn'iing a circuit 22 are connected 16. A control switch fifiand ,fuses are provided in the motor circuit. In series with one wire of the circuit J2 is a thermostatic switch iii 'of any preferred construction, which acts to close the motor. circuit and start the motor when the tei'n 'ierature falls below a certain point, and to open .the motor circuit when the temperaturereaches the desired maximum. The motor may be controlled instead, or additionallytby'aswitch 25 closing circuit 22-,which switch'is connected by a chain or the like 9.6 to a pressure regulator, or a temperature regulator of a hot water orsteam boiler heatedby furnace 18.

In practice to reduce thea ir resistance, I prefer to coat the inner surfaces of the blower over which the air travels with a friction minimizing coating, such as some kind of varnish or enamel. As most of the parts of the blower are made of wood, this coating is regarded as i m orta'nt,' ifnot necessary. t

As previously stated, the curvature of the openings 15 of each annulus combines with the curvature of the walls of the openings 8 to provide a bell-shaped inlet for the air (Figure 6), with the smaller end-of the in let within therotor. As the, air enters it strikes the conical protuberances "14,. which constrict the air passage below the; inner ends of the blades. After passing'thisfpoint, the air expandsand is periphery of the rotor practically the full width of the casing.

Stated in other language, the curves of the entrance orifices in the casing sides in connection with the openings atythe rotor sides have been designed to give easy acceleration to the entering air, and this is made possible by the thick lightmaterial used. It is common in blowers to haveflaring entrances in or on the case, but I know of no instance where this is followed through into the rotor. In designing the .rotor, I have avoided sharp turns and angles of every description and passes over curves in its passage.

The rotor is divided into two parts by the disk 11 for several reasons, the principal of which is that it has been found more de-. sirable to have the streams of entering air at each side met by a solid wall of material than to be allowed to cominingle. The disk everywhere the air-meets or delivering its and are led-lo the motor discharged at the 11, which forms the partition in this blower, is tapered off at the edge and is preferably, though not necessarily, smaller in diameter than the rotor, so that the air currents are permitted to meet only after passing a certain distance through the rotor. The whole idea in the entrance and rotor curves is to present logical curves for air currents and to simulate the shape of a Venturi meter.

The air from the rotor is delivered into the fullwidth of the rectangular passage of the casing, the section of which passage increases with a constant increment, thus cutting down the internal friction loss of eddy currents.

By employing the preferred embodiment of the invention for the purpose described above, the lower and cheaper grades of coal, such as buckwheat, barley, culm, or river coal or coal yard screenings may be successfully burned in ordinary house heating plants, with great resultant economies. It will be understood, however, that the invention is not limited to any particular use, and that many changes may be made involving alteration, omission, addition, and substitution of parts provided the resultant structure lies fairly within the scope of, the appended claims.

What is claimed is 1. In a blower, a casing having inlet openings in opposed walls, each tapering inwardly, a drive shaft projecting through one of said openings and supporting within the casing a symmetrically contoured hub formed by flares having their origin in the shaft and terminating at the periphery of the hub, transverse blades carried by the hub and hearing at their ends annuli, openings in said annuli conforming with those in the casing to form a bell-shaped inlet for the air, the inner faces of said annuli tapering from the periphery towards the centre.

2. In a blower, a plane sided volute profiled casing, inwardly tapered opposed intake openings in the casing centered at the origin of said volute, a drive shaft free of the casing and projecting through one of said openings, a disk supported on said shaft within the casing and having symmetrical flaring surfaces originatin in the shaft and terminating at the periphery of the disk, transverse blades "carried b said disk and annuli carried by said bla es on each side of said disk, the said disk, blades and annuli constituting a unitary duplex rotor, central openings in said annuli communicating with and merging into the openings in said casing, the surfaces of said openings forming with the complementary surfaces of said disk air passages having their most restricted cross areas within the rotor.

23. A blower as claimed in claim 2, in which the inner lateral surfaces of the annuli taper outwardly from the central openings towards the casing at the peripheries of said annuli, the minimum space between said in ner surfaces of the annuli being adjacent the openings.

In testimony, that I claim the foregoing as my own, I have hereto aflixed my signature.

CHARLES FREDERIC GERMEYER.

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