US2264071A - Rotary blower and exhauster - Google Patents

Description

Nov. 25, 1941. v. v. .DIBOVSKY 2,264,071 I ROTARY BLOWER AND EXHAUSTER Filed Sept. 7, 1939 In vennr.

D /bra Patented Nov. 25, 1941 r UNITED STATES PATENT OFFICE ROTARY BLOWER AND EXHAUSTER Victor yladimirovitch Dibovsky, London, England Application September 7, 1939, Serial No. 293,6 74

In Great Britain July 19, 1938 2 Claims. (01. 230-127) This invention relates to rotary blowers and livered by the blower may be utilised the rotor exhausters for air or otherelasti fluids of the may be mounted within a casing comprising a kind having a rotor embodying arr-annulus occudisc having a central bore for the passage of the pied by a set of blades and a central part from shaft of the driving motor, an annular plate and which air is drawn. 5 a side wall extending between the outer periph- The invention is based upon the discovery that ery of the annular plate and that of the disc and such blowers and exhausters depend for efficiency provided with an outlet. This side wall may be upon a proper correlation of the volume of the of spiral form so that its continuation after enannular space swept by the blades and that of circling the rotor forms one wall of the outlet the central part from which the air or other referred to, but preferably is substantially cylinelastic fluid is drawn and upon the cross-section drical and co-axial with the rotor, the outlet beof the annular space and that, furthermore such ing arranged tangentially, since by this means blowers can be made capable of delivery at exhigher pressures may be obtained at the outlet.. tremely high velocity if the blades are of suit- The disc and annular plate may be arranged able design and arrangement. quite close to the disc and annular plate respec- According to the present invention, in a rotary tively of the rotor and the side wall quite close to blower comprising a rotor embodying an annulus erp y 0f the rotor, but uc an ran occupied by a set of blades and a central part ment tends to make the blower noisy in operafrom which the air or other elastic fluid is drawn, tion, a high pitched whistle developing with high the volume of the space swept .out by the blades rates of revolution of the rotor. Preferably,

is substantially equal to that of said central part, therefore, the casing is spaced somewhat from and the axial length of said annulus is substanthe rotor and it is especial y desir l that t tially equal to the radial depth thereof. side wall should besituated away from the pe- Preferably the curvature of the rotor blades iph y f the t The volume of the sp in end view decreases with distance from the axis between the p p y f the o or and the side of the rotor; thus the blades may be most suit- Wall of the casing natu al y d p nds upon t ably of parabolic v tur For highest mrelative siZes of the casing and rotor .and it is in ciency, as when extremely high velocity delivery general un a y o t s Vo ume o exceed is desired, the blades should be arranged so that that Of the Space Swept y e blades, a d it the chords of the blades lie at an angle of not maybe de r especially n e b ower is more than say between 20 and 35, 'to radii intended a high V y very rather t an drawn from the rotor axis to the outer ends of h quahtitive u p t at the V lume should the blades, while the angle between the chords be considerably less than this, it may be of the blade and radii to the inner i. e. the leadabout one half of the volume of the pa e swept ing, ends of the blades, which will naturally be 35 by the bladeslarger, hould t b substantially greater The cross-sectional area of the outlet from the th n 65, casing at its nearest point to the rotor is prefer- It has been found that the number of blades ably at least q a t that f h u a spa employed has an important bearing upon the swept y t e rotor blades. The orifice in the emciency of the blower and that optimum re- 0 annular plate of the Casing is e b y of Subsults are obtained regardless of the size of the ay e same diameter as that in the anr t by employing six m s, While t blades nular plate of the rotor so that the air or other may in general be of uniform thickness they may elastic fluid entering the space at the centre of if desired be of aerofoil cross-section, the latter the rotor is not obstructed. This orifice may form of blade being especially suitable for rela- 81 to a intake p pe SO that the blower can tively large rotors. be connected to a particular source of air or The rotor may comprise a disc and an annular other s ic fluid. plate between which the blades are secured, the The invention has been described more particdisc being provided at its centre with means for ularly in connection with a rotary blower and securing it to the shaft of a driving motor. Prefthe inVentiOh i of especial importance n this erably the disc is also provided at its centre and n i n, s n it a l s a w r capable of On its blade-carrying face with a cusp shaped delivery at extremely high velocity to be condeflector, the concave face of which deflects air structed; indeed it is possible to construct a entering the centre portion on to the rotor blades. blower in accordance with the invention in which In order that the air or other elastic fluid dethe velocity of the air or other elastic fluid as it leaves'the blades is substantially twice the peripheral speed of the rotor. However, as previously indicated, such a blower may be employed for suction purposes, i. e. as an exhauster, with equal efficiency, and when thus employed the casing described may be omitted or may be simplified, e. g. an air intake may be arranged close to the orifice in the rotor and connected to the point at which it is desired to apply suction.

In the accompanying drawing, which illustrates an embodiment of the invention, Fig. 1 is an underneath plan view of the blower casing.

Fig. 2 is a sectional view of the assembled rotor and casing, two rotor blades being omitted for clarity, and

Fig. 3 is a plan view of the rotor.

Referring to the drawing the rotor comprises a disc I and an annular plate 2 between which blades 3 of substantially parabolic curvature are secured by means of rivets 4. The blades 3 are arranged so that their curvature in end view decreases with distance from the rotor axis and so that the chord be of each blade lies at an angle cab of somewhat less than 30 to a radius ac drawn from the rotor axis to the outer end of the blade and at an angle clad of somewhat less thanblades 3 comprises the annular space encompassed by the axial length 1 between the annular plate 2 and the disc I and the radial depth bd of the blades 3. This volume is substantially equal to that of the central part of the rotor from which air is drawn and encompassed by the axial length Z and the distance bf between the inner edges ofthe blades 3.

7 The disc I is provided with a central cusp shaped deflector member 5 bored centrally to receive the shouldered shaft 6 of the driving motor (not shown), the shaft 6 being threaded at its end to receive a nut I domed to continue the curvature of the deflector member 5.

. The rotor is mounted within a casing comprising a disc 8, an annular plate 9 and an encircling side wall Ill. The disc 8 has an aperture H for the passage of the shaft 6 while the annular plate 9 is provided over its aperture with a dome shaped closure I2 leading to the inlet pipe l3. The encircling wall I0 is of cylindrical form and is coaxial with the rotor and is provided with a tangential outlet pipe M the cross sectional area of which at s being at least equal to the volume of the space swept by the blades 3. r The disc 8 of the casing is secured to the encircling side wall ID by means of bolts l5 and nuts I6 and the casing itself is secured to the motor housing (not shown) or brackets carried thereby, e. g. by means of the same bolts 15.

In Fig. 2 there is shown in dotted outline a deflector member 5a which may be employed instead of the deflector .5. The member 5a is of parabolic curvature and occupies a large part of the central area of the disc and is especially suitable for use with relatively large motors.

I claim:

1. A rotary blower or exhauster for air or other elastic fluids comprising a rotor embodying an annulus, a set of curved blades occupying said annulus and surrounding a central part from which air or other elastic fluid is drawn, said curvature in end view decreasing with the distance from the axis of the rotor, said blades being so arranged that the chords of the blades lie at an angle of between 20 and 35 to radii drawn from the rotor axis to the outer ends of the blades, while the angle between the chords of the blades and radii drawn to the inner ends of the blades is not substantially greater than 65,

the inner edges of said blades forming the leading edges and the concave faces of said blades forming the leading faces, a cusp shaped deflector adapted to deflect the air or other elastic fluidentering the central part on the blades, and a casing for said rotary blower having a side wall provided with an outlet, the cross-sectional area of which at its nearest point to the rotor is substantially equal to that of the annular space swept by the rotor blades, said side wall being of cylindrical form and co-axial with the rotor, and said outlets being arranged tangentially to said rotor annulus, and the volume of the space swept by the blades being substantially equal to the volume of the central part from which air or other fluid is drawn, the axial length of the annulus being substantially equal to the radial depth, thereof.

, 2. A rotary blower or exhauster for air or other elastic fluids comprising a rotor embodying an annulus, a set of six blades occupying said annulus and surrounding a central part from which air or other elastic fluid is drawn, said rotor blades being of parabolic curvature, said curvature in end View decreasing with the distance from the axis of the rotor, said blades being so arranged that the chords of the blades lie at an angle of between 20 and 35 to radii drawn from the rotor axis to the outer ends of the blades, while the angle between the chords of the blades and radii drawn to the inner ends of the blades is not substantially greater than 65, the inner edges of said blades forming the leading edges and the concave faces of said blades forming the leading faces, a cusp shaped deflector adapted to deflect the air or other elastic 'fluid entering the central part on to the blades, and. a casing for said rotary blower having a side wall provided with an outlet, the crosssectional area of which at its nearest point to the rotor is substantially equal to that of the annular space swept by the rotor blades, said side wall being of cylindrical form and co-axial with the rotor, and said outlet being arranged tangentially to said rotor annulus, and the volume of the space swept by the blades being substantially equal to the volume of the central part from which air or other fluid is drawn, the axial length of the annulus being substantially equal to the radial depth thereof.

VICTOR VLADIMIR-OVITCH DIBOVSKY.

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