US1495873A - Fan or impeller - Google Patents

Description

B. SCHMELZER FAN on IMPELLER May 27 'Filed Aug. 9 1922 A TTORNE Y Patented May 27, 1924.

UNITED. STATES BRUNO SCHMELZER, or JERSEY our, NEW JEitSEY. 2

FAN on IMPELITER/ Application filed August 9, 1922. Serial no. 580,785

To all whom it may concern:

Be it known that I, BRUNo SGHMELZER, a citizen of Poland, and resident of Jersey City, in the county of Hudson and State of New Jersey, have inventeda certain new and useful Fan or Impeller, of which the following is a specification, the same being a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention which constitutes the sub ject matterof this application relates to improvements in centrifugal fans, compressors, air and gas pumps, fan blowers, andother kindred apparatuses which are hereinafter designated as-fans; and its has for its object the provision of an improved construction of that type of fan wherein a .flow of air, water or other fluid (hereinafter referred to as air) is discharged from the fan wheel.

Another object of, the invention is to increase the efficiency of such fans and to eliminate the noise ordinarily incident to the operation thereof.

In many centrifugal fans where the air is taken in axially and discharged circumferentially the current which is discharged from the backor disk portion of the blades has a tendency to cross over toward the intake end and to re-enter the lnterior of the fan centripetally, and I have therefore de signed my fan so that the fluid that passes being to aconsiderable extent a re-circulation back from the discharge side, whereby by my invention the air entering centripetally through the inner end of the blades and passing axially between or along the same is discharged centrifugally from the outer portion of the blades without any objectionable re-circulation thereof, thus enabling the fan to operate with a maximum efficiency and without undue noise.

The noise produced by high speed centrifugal fans is also ordinarily caused by the fluid being forced to pass over sharp edges whereupon it ceases to flowsmoothly and becomes broken .up into whirls or eddies thus forming a turbulent mass.

the rear edges of the blades where the air is drawn inby. suction and concaving the anterior face of said blades an unobstructed channel for the even andsteady movement] By o d ofthe fluid is provided, thereby avoiding the setting up of any sharp edges to interfere in any manner'with the smooth passage of the current. 7

Another source ,7 of excessive'noise insuch fans is the formation of thin blasts of air passing laterally' by the fan blades and between the same and the casing, which blasts conflict with the normal centrifugal flow of the current and produce eddies and vortices in the air movement and cause backpressure.

"Again, interstices between the fan wheel and the casing, orirregularities in the inner face of the latter, serve in many fans to constitute pockets in which air is compressed by the centrifugal current and, on account of the tendency of such air cushions to expand against the said current, friction is created which develops a harsh and severe noise. fan wheel made with truncated cone shape side portions which conform in contour with the casing will eliminate the above:

named disadvantages. I

' Wlth the above considerations in mind and witha view of overcoming the objections pointedout, I have devised the fan illustrated in the accompanying drawings, in" -'which' 1 FigureQ is a transverse section of the same. I p A As 'one'example or embodiment of the invention I have illustrated the same as applied to a radial flow fan in which the fluid operated upon enters axially and centrally in the inlet and is discharged circumferentially at the outlet of the casing or housing. The fan wheel comprises a disk or back plate or wall 3forming a convex deflector 3 and a shroud, ring, annulus or forward wall 4, intermediate of which are positioned a-plurality of im peller blades 5.

The fan wheel comprises approximately radial spokes or arms Qcarried by a shaft 2 which works in a casing 1. The back plate 3 and shroud 4t and outer portions of the said arms are preferably of cone-shaped contour,

'the fan wh eel thus comprising truncated coneshaped side portions. Th'eflblades are consequently made with preferably outwardly converging edges. The inner portion of the shroud terminates in a-flat horizontal The interior face' of the casing is preferably so formed as to correspond with the said contour of the fan wheel both in longitudinal and cross section through any blade, and the side wall or head 1; of the casing at the intake end of the blades ispreferably detachable and made with an inlet tube 1 projecting into and beyond the said ring l.

The inner ends 5' of the blades project forwardly so that the air when drawn in by suction will not strike a sharp edge, and the impeller blades are preferably ofsubstantially radial position, and the anterior taces'of the same as well as the outer portions ofc the arms2"are preterably concavedasat 5? so as t aif a moo h n e y pa g o the current, although thesame maybe'ot different inclinatien, curvature or thickness Withoutd nartius fre n hen incipl Qfmy V invention which is applicable to 7 othertypes 'are contained in the recessed portions or pockets ordinarily present in fan casings or of blades! he fluid nte ins the int ke" cadet t n p s sb y e. po nte end theshat 2 formlng c 1i6a e ete r aadf s car ied o n e we th has pl e er' disk M 9 v shroud and discharged without striking. or impinging upon adverse air currents such-as rhousings-or meeting any obstruction'or opposing element whatever and also without having any chanceto enter the intake again and to re-circulate. wheel the air is guided from theintake side to the centre of the casing trom'which it is peripherally discharged in'a strong andeven.

flow of current On account of the air enteringwithin the plane of the adjacentside of the fan wheel,

' and crossing a-portion of the interior edges of the blades by the use of the tubular inlet 1 there is no obstruction of the fluid ,in its normal axial progress within-the boundary of the fan as the arms 2' do not interfere with strengthenedby the outer ends of the arms.

2* which, together withthe' blades are concaved whereby great stiffness and rigidity. are attained. Theouter portions of-the disk; and shroud and also'the' casing extendinwardly in cone-shaped contourto the enteredge of the bladeslto: correspond;With-the:

- converging edges of the blad s, Byrreasonof the circumferential channel of; =t-he casing f being narrowed near its outer portion-sofas to be of the same width as the-exterior? edges;

' of the blades acontractedchannel continuing.

of the same diminished width to the outlet 7' By my conical fan of the casing is formed and consequently a concentrated blast is secured, while at the same time on account of my peculiar con- 7 struction of parts there are no air cavities in my device to set up friction against the cur-V rent flow or to cause any of the said air current tobecome choked backward at any point of the movement of the fluid. 7

I wish to have it understood. that I do not desire to be limited to the-particular use or theexact details of construction shown and described, for obvious modifications will oc eur to persons skilled in the art. VVha't I claimas myinventioncisi 7 1 In a device of the class described, a ca-s- 111g compr sing unobstructed inlet and outlet open mouths, afan wheel having a fan shaft with a single set of-spokes lyingin-thecentral plane of the wheel and provided with concave blades supported thereby, theffan Wheel having an open channel therethrough at andbetween the inner edges-fof'the blades of substantially the diameter of thein'let wherein the airgfe'nteringaxially is ;ca used to graduallyrotate circumferentially before being acted upon in said channel by the Wheel to avoid ,ainpock'et resista11cc,the said blades havinginner edges adapted to" cut the;

surrounding air edgewise with wedging action, in the path d'ftravel, the casing lying sutliciently near the sides otthe'wheel as to prevent back pressure orjsluct ion resistance therebetween to avoidfharsh noises.

from emanating. from the fan},

2. ln adevice of the clss described,

casing. comprising; unobstructed inlet and outlet open mouths, av fan wheel having a tan shaft with a, singleset of spokes lying in the central plane of thewheel'and provided V with concave blades supportedthereby; the fan- Wheel having an open channel therethrough at and between the inner edges, of

the blades of substantially the diameter of the inlet wherein the air entering axially is-caused t-o gradually rotate circumferentiallywbefore being acted upon in said channelby the: spokes-to avoidlair-pzocket resistance, the said blades having forwardly,

curved inner edges adapted tojcut the surrounding air edgewise'with a wedging'action in the path of travel, the'casing lying tfiei nt y near he si es. of t e hee as to prevent back pressure or suction 'resi st ance therebetween to avoid harsh noises fr memanat ngf m th fa In a device/oi the class described, a

casing eompr-ising inlet and outlet open mouths, a;;f;an wheel having a fan'shaft and provided ith on a e blade Supp r h re n, he n h l; ha ingn pe ha nel-"therethrough at and between the inner ge c the bla es q -s sb n a y h d me; ndt he, inlet where n. he a r.e ri

axially is; caused to; gradually rotate cir eumferentially bysuction to avoid aiapoca the adjacent parts of the casing lying close to and parallel therewith the entire extent of said edges, the shroud terminating in a ring concentric with the inlet and the latter projecting into the said open channel, the

ring and open channel being substantially of the same diameter.

4. In a device of the class described, a casing comprising inlet and outlet open mouths, a fan wheel having a fan shaft and provided with concave blades supported therein, the fan wheel having an open channel therethrough at and between the inner edges of the blades of substantially the diameter of the inlet wherein the air entering axially is caused to gradually rotate circumferentially by suction to avoid air-pocket resistance, the said blades having inner edges adapted to cut the surrounding air edgewise with a wedging action in the path of travel, the casing lying sufficiently near the sides of the wheel as to prevent back pressure or suction resistance therebetween to avoid harsh noises from emanating from the fan, the blades of the fan wheel being positioned intermediate a disk and shroud and having outwardly converging edges, and the adjacent parts of the casing lying close to and parallel therewith the entire extent of said edges, the end of the fan shaft carrying a conical deflector and the disk having a c0nvex portion rotating within the said open channel to provide deflecting means of larger diameter to create an increased flow of air thereat, said convex portion conforming to the contour of the adjacent part of the casing.

5. In a device of the class described, a casing comprising unobstructed inlet and outlet open mouths, a fan wheel having a fan shaft and provided wit-h concave blades supported. thereby, the fan wheel ,having an open channel therethrough at and between. the inner edges of the blades of substantially the diameter of the inlet wherein the air entering axially is caused to gradually rotate circumferentially before being acted upon in said channel by the wheel to avoid air-pocket resistance, the said blades having inner edges adapted to cut the surrounding air edgewise with a wedging action in the path of travel, the casing lying sufliciently near the sides of the wheel as to prevent back pressure or suction resistance therebetween to avoid harsh noises from emanating from the fan, the blades of the fan wheel being positioned intermediate a disk and shroud and having outwardly converging edges, and the adjacent parts of the casing lying close to and parallel therewith the entire extent of said edges, the outlet channel of the casing being eccentric with respect to the fan wheel and of the width of the narrow outer edges of the blades and continuing of the said contract/ed width to the mouth thereof and being narrowest just above the said mouth.

- Signed at New York in the county of New York and State of New York this 23rd day of June A. D. 1922.

BRUNO SC HMELZER.

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