US1199374A - Conical-flow fan. - Google Patents

Description

H. F. HAGEN.

CONICAL FLOW FAN. APPLICATION FILED 1AN.13. 19|3.

Patented Sept. 26, 1916.

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n Hom/1213 ya ya. w )M1/W H. F. HAGEN. CONICA!- FLOW FAN. APPLICATION FILED JAN. la. 1913.

Patented Sept. 26, 1916.

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UNITED STATES PATENT OFFICE.

HAROLD F. HAGEN, OF JERSEY CITY, NEW JERSEY, ASSIGNOR T0 THE GREEN FUEL ECONOMIZER COMPANY, OF MATTEAWAN, NEW YORK, A CORPORATION OF NEW YORK.

CONICAL-FLOW FAN.

Application led January 13, 1913.

To all 'whom it may concern Be it known that I, HAROLD F. HAGEN, a citizen of the United States, residing at Jersey City, New Jersey, have invented certain new and useful Improvements in Conical-Flow Fans, of which the following is a full, clear, and exact description.

The invention which constitutes the subject matter of this application, relates to a diffuser applicable to fans, compressors, pumps and other kindred apparatus.

It is well known that the axial flow or propeller type of fan is especially7 desirable where large quantities of air lare to be moved but only against comparatively low pressures. It is also known that with the radial flow fan, generally called the centrifugal fan, it is extremely difficult to Secure a large volume of air at a moderateA pressure and still secure a high efficiency unless the fans are made of a very large size so that the velocities of the fluid through the passages are such as to make the velocity heads small.

Radial flow fans necessitate the turning of the air through a right angle, and inasmuch as a large volume at moderate pressure requires large air passages, it is difficult to secure, mainly on account of the above mentioned right angle turn, an even distribution of the air. As a result radial fans designed for large volumes, work rather inefficiently.

Any rotating impeller which imparts energy to a fluid passing through it, must give the particles of that fluid a rotative velocity component in the direction of the rotation of the impeller. This rotative velocity component is in fact a measure of the amount of work doneby the fan. Consequently if the volume delivered is constant a fan developing a high pressure, that is doing a' large amount of work, will necessarily impart to the fluid particles a rather large rotativel velocity component; and a fan working at a low pressure, doing a small amount of work will impart to the Huid particles a smaller rotative velocity component. In a radial fan, this component of the velocity is useful and appears, though somewhat diffused, as useful velocity head at the outside of the volute.v But in the axial fiow fan the head represented by the rotative velocity component at the Specification of Letters Patent.

Patented Sept. 26, 1916.

serial No. 741,717.

fan outlet is entirely lost. It serves no useful purpose in moving the fluid through the passages. For this reason an axial flow fan cannot Work efficiently at other than very low pressure where this waste energy is small.

I have found in all fans as hitherto constructed that the sides v,of the walls have not had the proper relation with respect to each othervand the direction of the fiow of the fiuid therethrough inasmuch as the streamrdoes not fill the space between the walls owing to the fact that the area of the space always increases in the direction of flow whereas the area should remain sub'- stantially constant in order to obtain the best results in the conversion of the rotative velocity energy into pressure energy.

The invention therefore consists in providing mechanism for converting this rotative velocity of the axial or propeller type fans, with their excellent distribution of the fluid, into higher pressures with good efficiencies, by providing a diffuser therefor of the type described in detail below. This diffuser is employed to provide an efficient means for converting the rotative kinetic energy into useful potential en rgy or static pressure through the actio of the law of the constancy of the moment of momentum. This diffuser therefore may be applied to an axial fan thereby increasing its pressure range and its efficiency.

Referring to the drawings, wherein lI show the preferred embodiments of my invention; Figure 1 shows a construction of a fan embodying the principle of my invention wherein the inner and outer co-axial wallsof the diffuser are curved concavely with respect to the axis of the fan. Fig. 2 illustrates a modified construction which is an approximation of the device shown in' Fig. 1. Fig. 3 shows a construction of a fan embodying the principle of my invention, the walls of which are curved in a direction which is convex to the axis of the fan and approach each other as theradial distance increases. Fig. 4 illustrates a modification which is an approximation of the device shown in Fig.

The essential feature of my invention, as will appear from the embodiment shown, consists in the provision of a space which is substantially free from eddies and is accomplished by employing co-axial members the walls of which are so inclined to the axis that they approach each other as the radial distance from the axis increases.

Referring specifically to Fig. l, the character A represents the interior wall or member and the character B the exterior member which is co-axial with the member A both of which are stationarily mounted, the member B preferably secured to the suction ring C by means of bolts shown at D, and the member A is preferably secured to the member B by the means shown at E. The suction ring is in turn preferably supported byasuitable base, such as shown at F. The surface of the members or walls A and B are connected by strap-iron supports and approach each other in the direction of fiow of the gases therethrough in the manner above stated. As a result of so placing the two surfaces not only is the forward velocity of the entering fluid diffused, but the circumferential velocity is diffused as well.

Fig. 2 shows a construction similar to the construction shown in Fig. l; but in this case the members A and B are co-axial conical members and are so arranged, as in Fig. 1, that the area between the surfaces, that 1s the area these surfaces intercept on planes perpendicular to the axis of the shaft, is substantially constant, and the walls of the diffuser are inclined toward each other in the direction of the flow of fiuid therethrough. For instance, this area at the point of entrance of the fluid between said surfaces is equal or substantially equal to this same area at the point of exit of said Huid.

In Fig. 3 I have shown the same principles embodied in a diffuser wherein the walls A and'B are curved reversely to the curvature of the walls shown in Fig. 1, and also approach each other as the radial distance from the axis of the fan increases. The device is so constructed that the sectional area at increasing radial distances is substantially constant, or very slightly decreasing, and the formation of the path of the fluid through the fan is changed from an axial into a substantially corneal direction.

Fig. 4 shows a form of diffuser which approxlmates the walls of the construction shown in Fig. 3 and for practical purposes, like the construction shown in Fig. 2, may be used with substantially the same efficiency. These defining walls like those shown in Fig. 2, are also co-axial conical members the outer surfaces of which are inclined toward each other in the direction of the flow of fluid therethrough.

With reference to the construction of my conical flow diff'users as shown in Figs. 1 and 3, the exact inclination of the walls is perfectly determined in accordance with the theory of whirl-free stream line motion. In

my investigations, however, I have found that the limiting walls of the diffuser to be in exact accordance with thistheory will be curved, either concavely or convexly with respect `to the axis of the flow, and approach each other as the radial distance from the axis of the fan increases. I have also found that these walls can be curved differently with respect to the axis of the fan and 0f course each will be expressed by different mathematical equations or formulae. I give one of the mathematical equations of my invention below:

Equation l K---Cac-Dr2 where C is a constant, the axial distance from the origin and D is another constant. This equation is the formula of a. parabola and is arrived at from the underlying principles of the theory of whirl-free stream line motion. In order to avoid the prolixity of description I will not enter into a discussion of the necessary steps in arriving at the conclusion, as it is thought that this will be clearly understood by those skilled in this particular art. By regarding K as the parameter and assigning to it different values the equation may be considered to represent a family of congruent parabolas. Using these to represent a fluid flow, we have a mathematical expression of the action of the fluid. Any two of the congruent parabolas may be taken as the limiting walls of the diffuser and through this passage, defined by the limiting walls, the fluid can flow 100 free from whirling motion. A construction in accordance with this equation is illustrated in Fig. 1, in which the curves are concave toward the axis of the fan. From the underlying principles of the whirl-free 105 theory other formulae may be developed and the limiting walls of the diffuser constructed in accordance therewith to provide a substantially conical passage through which the fluid can fiow free from whirling motion.

Another mathematical equation which may be evolved from the underlying principle of whirl-free stream line motion is the following:

where C is a constant, r the radial distance from the axis of the fan, and .fr the axial distance from an origin. By regarding K 120 as the parameter and assigning to it different values the equation will be found to represent another family of curves which approach each other as the radial distance from the axis of the fan increases. In using 125 these curves again to represent a Huid fiow we have a mathematical expression of the action of the fluid any two of which may be taken as the limiting walls of the diffuser which walls define a passage free from 130 whirling motion.

A diffuser constructed in accordance with this equation is illustrated in Fig. 3 in which the curves are shown as being convex toward the axis of the fan. As in the case of the diuser illustrated in Fig. 1 other formulae may be developed and the limiting Walls of the diffuser constructed in accordance therewith to provide a passage through which the Huid can flow free from whirling motion. Of course in designing a diffuser the values assigned to the constants of these equations must be selected with due regard to the nature of the fiuids. It will be apparent, however, that in the construction shown in Fig. 3 the change of width of the passage formed by the limiting Walls of the diffuser is greater owing to the fact that the radial component of the velocity increases more rapidly with respect to the axial component than is the case with constructions made from formulae which represent lines curved reversely from the lines illustrated in said Fig. 3.

I have also found as a matter of fact that if conical Walls, such as shown in Figs. 2 and 4, and having substantially the same degree of inclination,be substituted for the curved walls they give a result in operation which approximates the efficiency derived from the curved Walls and are preferred in actual practice where diffusers manufactured from sheet metal are required and in these cases the flow of fluid through the passage will be substantially whirl free.

It Will be very apparent from the above description that lar e changes in the velocity of the Huid Wil be effectively avoided in passing through the diffuser. As a result, the formation of eddies is prevented 2nd the flow through the passage whirlree.

In all the embodiments herein shown an impeller with suitable blades G is used, properly disposed upon the shaft H.

It is to be understood that I do not limit myself to the exact constructions shown, as many changes may be made in points of detail and other embodiments resorted to without necessarily departing from the spirit and scope of the invention as defined by the appended claims.

That I claim is:

l. In combination, a rotary impeller and a diuser comprising inner and outer Walls or casings defining a substantially conical passage for the flow of' fluid therethrough, said walls so related that the areas they intercept on the surface of cylinders coaxial With the axis of the iinpeller increases substantially in direct proportion to the radius of such cylinders and also the area intercepted by said diffuser walls on planes perpendicular to the axis of the impeller is substantially a constant.y whereby the radial and rotational velocity components are decreased While the axial velocity component is kept constant, and a conversion from velocity to pressure is secured and eddies are avoided.

2. In combination, a rotary impeller, and a diffuser comprising outer and inner limiting walls or casings defining a substantially conical passage for the flow of fluid therethrough, said walls so inclined to the axis that they approach each other as theradius increases, and continue throughout their whole extent the same direction of curvature toward the axis as the limiting walls of the impeller with which they are combined.

In testimony whereof I affix my slgnature in the presence of two subscribing witnesses.

HAROLD F. HAGEN.

Witnesses:

WM. BOHLEBER,V M. LAWSON DYER.

Correction in Letters PatentNo.,1,199,37f1f.

' requiring whirling motion. A diffuser constructed in accordance With this equation is illustrated in Fig. 3 in which the curves are shown as being convex toward the axis of the fan. As in the case of the diffuser illustrated in Fig. l other formulae may be developed and the limiting Walls of the diffuser constructed in accordance therewith to provide a passage through Which the fluid can flow free from whirling motion. Of course in designing a diffuser the values assigned to the constants of these equations must be selected with due regard to the nature of the fluids. It will be apparent, however, that in the construction shown in Fig. 3 the change of width of the passage formed by the limiting walls of thediffuser is greater owing to the fact that the radial component of the velocity increases more rapidly With respect to the axial component than is the case With constructions made from formulae which represent lines curved reversely from the lines illustrated in said Fig. 3.

I have also found as a matter of fact that if conical Walls, such as shown in Figs. 2 and 4, and having substantially the same degree of inclinatiombe substituted forthe curved walls they give a result in operation which approximates the efficiency derived from the curved Walls andare preferred in actual practice where diffusers manufactured from sheet metal are required and in these cases the flow of fluid through the passage will be substantially whirl free. Y

It will be very apparent from the above description that large changes in the velocity of the fluid will be effectively avoided in passing through the diffuser. As a result, the formation of eddies is prevented nd the flow through the passage Whirlree.

In all the embodiments herein shown an the same [SEAL] increases, and

Signed and sealed this 6th day of March, A. D., 1917.

impeller with suitable blades G is used, properly disposed upon the shaft H.

It is to be understood that I do not limit myself to the exact constructions shown, as many changes may be made in points of detail and other embodiments resorted to without necessarily departing from the spirit and scope of the invention as defined by the appended claims.

What I claim is:

l. In combination, a rotary impeller and a diffuser comprising inner and outer walls or casings defining a substantially conical passage for the flow of fluid therethrough, said walls so related that the areas they intercept on the surface of cylinders coaxial with the .axis of the impeller increases substantially in direct proportion to the radius of such cylinders and also the area intercepted by said diffuser walls on planes perpendicular to the axis of the4 impeller is substantially a constant, whereby the radial and rotational velocity components are decreased while the axial velocity component is kept constant, and a conversion from velocity to pressure is secured and eddies are avoided.-

2. In combination, a rotary impeller, and a diffuser comprising outer and inner limiting Walls or casings defining a substantially conical passage for the flow of fluid therethrough, said walls so inhlined to the axis that they approach each other as the-radius continue throughout their whole extent the same direction of curvature toward the axis as thelimiting walls of the impeller With which they are combined.

In testimony whereof I affix my signature in the presence of two subscribing Witnesses.

, HAROLD F. HAGEN. Witnesses:

WM. BOHLEBER, M. LAwsoN DYER.

It is hereby certified that in Letters Patent o; 1,199,374, granted September 26, 1916, upon the application of Harold F. Hagen, of Jersey City, New Jersey, for an improvement in Conical-Flow Fans, an error appears inthe printed specification correction as follows: Page 1, line 52, for the Word outside read outlet; and that the said Letters Patent should be read with this correction therein that may conform to the record of the case in the Patent Office.

a. W, ILH. LAY,

I Acting Uommissioner of Patents.

Correotion in Letters Patent No. 1,199,374.

It is hereby certified that in Letters Patent No. 1,199,374, granted September 26,

. 1916, upon the application 0f Herold F. Hagen, of Jersey City, New Jersey, for an improvement in Geniaal-Flow' Fans, an error appears in the printed specification requiring correction as follows: Page 1, line 52, for the word outsice read outlet;

and that the said Letters Patent should be read with this correction therein that the same muy conform to the record of the case in the Patent OHce.

Signed and Sealed this 6th day of March, A. D., 1917.

E. W. H. CLAY,

[SEAL] Ming commissioner of Panne.

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