US2325222A

US2325222A - Air impelling apparatus

Info

Publication number: US2325222A
Application number: US299634A
Authority: US
Inventors: Walter H Bretzlaff; Charles P Grimes
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-10-16
Filing date: 1939-10-16
Publication date: 1943-07-27
Anticipated expiration: 1960-07-27

Description

July 27, 1943.' w. H. BRI-:'rzLAl-'F Erm. 2,325,222

AIR IMPELLING APPARATUS Filed oct. is. 193s 2 sheets-sheet 1 ("'L E, .//f/Z. 'T

SJQJA'AJM. 4

ATTORNEY.

July 21,1943. w. HBRETZLAFF mL 2,325,222

AIR IMPELLING PPRATUS Filed Oct. 16, 1939 2 Sheets-Sheet 2 W I i'lQLj ATTORNEY.

' .il G TUS Walter E. Bee, Detroit, limon, and Charles l?. Gee, syracn, N. Y.

Application @stoner i6, :1939, Serial No. 299,634 il. im. 2363-4117) This invention relates to an improved blower for moving liquids, air or gases under pressure and at high velocity with a minimum amount oi power and capable of edectlvely meeting the requirements under many conditions where blowers are required for various industrial, domestic, and automotive applications.

it is an object oi our invention to provide an improved blower which embodies, edective com operating means whereby power losses, .heretofore sustained in available commercial blowers are reduced and the ratio of volume and prese sure of air output to the power required to operate is greatly improved thus achieving more emcient and less costly operati-on.

It is a further object of the invention to pro videa quiet running, compact unit ci sturdy yet simple and accessible structure embodying few parts such as can be economically produced.

An additional object is to provide more ecient delivery of collected air by providing a substantially concentric collecting chamber encircling e. propeller type impeller iacilitating de liversT` outlets being established in optional locations with respect to the periphery oi said chamber in one or more positions for eective and direct distribution and discharge to points of utilization with a minimum loss of the energy of the air accumulated in the chamber;

Another object of our invention is to provide a blower which is compact in sise compared to the amount of cubic space ordinarily reuuired for commercial blowers now in use which accord ingly provides further savings in costs due to the possibility of housing the component parte of air conditioning, heating, and other apparatus reqlring blowers in a cabinet or enclosure of greatly reduced size.

A further object of our invention is the provision of cooperating structurall elements in a blower housing adapted for utilization of disc type propeller fan structure impellers of low cost and light in weight for eective baiiling and air collecting means serving to direct the dow of air induced axially and advanced by the impeller 'in such a manner that the high velocity air from the discharge stream is entrapped in a suitable collector chamber and encouraged to rotate therein cooperatively, and in the same direction with the impeller thus causing the dischargev air to accumulate a. high component while at the same time due to the shape and position of the parts, provision is made for expansion and greater accumulation within the collector fromwhence tangential `outlet centrifugal and rotative ports may be eiectively arranged to provide direct delivery of air under pressure topoints of use with minimum loss of energythus accumulated.

Still another object is that of providing such an improved blower unit having resilient acoutical, electrical, and vibration insulated motor mounting means and in such relation to ad-` vanced air stream to insure eective forced ventilation of motor to prevent overheating.

Another object ofthe invention is to provide an improved blower unit in which the full volumetrlc emciency of the impeller is assured through the use of a closely coupled entiy port of greater area than the intake area of the im'a peller, the impeller being suitably devised to induce an axial now of air of relatively low velocity through its full intake area into'its plane of rotation and causing the air thus advanced tobe discharged radially and tangentially into the collector at high velocity.

A further object of our invention is to pro vide Aa double blower having opposed entry ports and utilizing propeller disc type fan impellers in reversed relation on a unitary drive shaft whereby induced axial ow provides balanced axial end thrust thereby eliminating end thrust bearing friction.

The invention itself, however, both as to its organization and its method of operation together with additional thereof, will best be understood from the follow ing description of specific embodiments, when read in conjunction -wlth the accompanying drawings, wherein similar reference characters designate similar elements throughout, in which:

Fig. l is a front elevational view of our improved blower unit;

Fig. 2 is a cross-sectional View therethrough taken along line 2-2 of Fig. 1;

Fig. 3 is a, similar view showing a modified embodiment of an air impeller apparatus; and

Fig. 4 is a similar view showing another modied embodiment of the air impeller apparatus.

Referring moreA specically to the drawings, we have shown ln Figs. 1 and 2 an improved uid impelling device arranged in accordance with our invention. The device shown is a. blower unit comprising an enclosing housing or shell i having peripheral side walls 3 which are of annular or cylindrical conformation. The side walls oi the housing may be made of any suitable ma.- terial or sheet metal of a proper gauge to provide a light, compact structure of the necessary objects and t advantages t through entry port towards motor.

ticular application desired, as will be readily understood.

At one end of the housing the edge of the side wall 3 is adapted to receive a circular or disc like end Wall and motor support 5 having an axially extending flange l around the outer edge for attachment to the housing side wall in any suitable manner, as by welding for example. A circular aperture 9, which is provided in the center of the wall member 5, has an outwardly ofl'set flange li around the inner edge. Extending toward the other or open end of the housing is a generally circular baille member, which may comprise an intermediate portion i3 of a generally cylindrical conformation having at one end an outwardly extending radial bafie wall I5.

Extending diate Wall i3 of the baffle structure is an inwardly radially extending wall i7 which is adapted to be secured snugly to the end wall 5, in any suitable manner, as by bolts i9. The inner edges of the inturned radial wall Il are made to denne or bound a central circular aperture 2| of a corresponding diameter and in alignment with the circular aperture 9 in the end wall, and the'margina] edge thereof is o-set inwardly to form a flange 23 forming in cooperation with the outwardly oH-set flange I i, an annular pocket 25 for receiving and clamping therein a compressible gasket 2l of any suitable yielding and insulating from the other end of the interme` material. For this purpose' we preferably use a strip of cork which has been grooved along one side which together with the off-set marginal flanges ii and 23 forms a socket for supporting an electric motor 29 in a central, or concentric position in the housing.

The electric motor 29 has a central circumferential fin 3i extending from the central section of its frame for fitting into the groove in the cork gasket 2l, and as the baille member i3 is bolted to the end Wall 5 of the housing the electric motor 29 is clamped resiliently but firmly into its socket in electrically and acoustically insulated relation from the housing. The shaft 33 of the motor is concentric to and extends axially in the housing toward the open end thereof and operatively receives the hub 35 of a disc type propeller fan 3l secured thereon by a screw 36 for operation in a proper direction to draw air The propeller type fan structure 31 provided has a suite able pitch and curvature to accomplish full flow of the air with minimum angle of attack for greater eillciency in power consumption. The propeller fan used may be any propeller type of fan impeller either forged, cast, fabricated of sheet metal or other material and referred to throughout as a propeller fan or impeller. The inner or discharge face of the propeller type fan 31 and the outer surface of the radial baille wall i5 are disposed in closely spaced relation for mutual cooperation in a manner to be described. A fin ring 38 is snugly fitted over the end of the motor frame to transfer heat effectively from the motor frame to the circulating air for cooling the motor.

The edge of the side wall 3 of the open end of the housing is turned in and back adjacent the fan blades to form a circular shroud 39 encircling the tips of the fan blades in closely coupled relation and separating the intake area of the fan from the discharge area in such a manner as to forxn an integral circular air inlet port Il of a greater area than the intake area of the propeller type fan, as shown, to provide for easy air entry throughout the entire entry area of the propeller fan. The entry port and the circular shroud are concentric to the fan and present a smooth air foil conformation to the entering air stream.

Also by means of this arrangement recirculation of air from the collector chamber is prevented and the full volumetric efficiency of the air impeller is obtained in operation.

The closely coupled shroud 39 cooperating with the walls of the housing and the baille i3 serves also to enclose a smooth annular chamber 42 disposed concentrically with reference to the air impeller for receiving high velocity air thrown radially by centrifugal force from the high velocity portions of the propeller type fan blades. The annular baille surface it adjacent the discharge side of the fan also serves to direct air advanced by the fan to enter the collector chamber and to become entrapped therein. This arrangement oi the air collector chamber also provides sufilcient axial space to expand the entrapped air axially in the housing, the smooth annular shape thereof also encouraging the rotation of the air advanced therein in cooperative relation to the rotation of the fan.

The concentric relation of the air collector chamber to the i'an facilitates delivering the entrapped air in such a manner as to utilize both the pressure head and the velocity head of the entrapped air to the greatest possible extent. Because of this concentric relation it is possible to provide a number of delivery conduits Q3 opening tangentially at desired points around the side walls of the concentric air collector chamber 42 to carry the entrapped airtangentially from the chamber and directly to the points of utilization without the necessity of having energy killing deviations and curves between the collector chamber and the point of utilization.

A mounting bracket i5 may be attached to the housing for mounting the simple compact blower unit in any convenient location preferably close to the points where the collected air is to be utilized, or in some installations the delivery conduits 63 may be attached for mounting the unit. By connecting the electric motor 29 through conductors 86 and any suitable switch or control device (not shown) to a suitable source of electrical energy, in a well known manner, the blower unit may be controlled conveniently to supply the desired volume and pressure of air in any desired location. In certain applications the shaft may be journalledconcentrically in the housing, as motive means for driving the fan, with energy from an external source.

In operation the central portion of the fan blades provide ample circulation of air around the cooling fin 38 on the electric motor 29 to provide eective cooling and, to the extent that the load capacity of an electric motor is usually limited by overheating, a smaller motor may be used in this arrangement for operating a fan of a given size. Also because of the improved efficiency of our improved air impeller apparatus, as previously explained, less power is required to move and deliver a given quantity of air, and this taken with the improved motor cooling arrangement renders it possible to use an electric motor which is much smaller. These factors all contribute in a. very useful manner to make our improved blower unit more compact, light and less expensive for a given capacity. l

Fig. 3 shows an axial cross-sectional view of another `embodiment of our improved air impelling apparatus being a double blower unit -in which a double inlet housing is formed of two oi the same cylindrical housing shells 3 which we utilized in the single fan blower unit. Shells 8 are joined together with the edges of the straight openv ends in adjacent abutting and aligned engagement. This is conveniently accomplished by passing the open edge oi one of the shells i3 about halt way over the outside of an annular ange Ell oi the size to fit snugly therein The engaged portions of the shell 3 andthe flange 5l are then joined in any suitable manner, as by spot welding for example. other shell 8 is then passed snugly over the outside of the other half of the ange 5l to which it is secured.

- The flange 5i is offset as shown and is a part of and extends axially from the outer edge of a circular partition membe- 53.` An aperture 55 is provided in the circular partition 53 of a diameter suitably larger than an electric motor 5l, which is mounted centrally therein, in a manner to be subsequently described.

ln our double blower unit we utilize a pair of the annular baille structures t3 or" a conformation similar to the baie used in the rst modiication. The baiiies i3 are clamped on opposite sides of the central partition member, as by bolts i9 extending therethrough, and the off-set iianges '23 together form an annular pocket for receiving and clamping therein the cork gasket 2l which, similarly to the preceding construction, is recessed to receive a circumferential fin 3i on longitudinal center of 'the motor. In this manner our double blower unit is conveniently assembled and an electric motor Eil is concentrically supported therein in electrically and acoustically insulated relation.

In our double blower unit the electric motor 5l is provided with a drive shaft 59 projecting from opposite ends of the motor and extending toward the opposite open ends of the housing. On each opposite extended end of the drive shaft 59 is firmly secured one of the disc type propeller fans 37. The two propeller fans 3l' are of similar capacity but are reversely or oppositely formed so that', as the shaft rotates the two fans simultaneously, two air streams are thereby moved axially and in opposite directions. The fans are so selected and mounted on the drive shaft that, when the electric motor .is energized and rotates'in a normal direction, air streams are drawn axially into the opposite open ends of the double housing. The annular baille surfaces |5 of the bailies extend adjacent the discharge edges of the fan blades, as in the rst form of our air impeller. And similarly serves to direct all air advanced by the impeller to move therefrom in the high velocity discharge area and to further avoid recirculation of such air as might otherwise reenter impeller at central low velocity discharge face. Thus all air advanced by said impeller is entrapped in the annular collector chamber formed by this radial baille element in cooperative relation to the housing. l

Through this arrangement is provided means for expansion and collection of advanced airunder pressure and having velocity characteristics so desirable in apparatus of this class While at the same time rendering the overall diameter of the unit considerably smaller in diameter that is possible where the commonly used radially expanding scroll is employed to provide this function.

Further advantage is gained inithis construction due to the possibility of optional location and number of tangential discharge ports as application and function may require.

The open outer ends of the side walls 3 of the two cylindrical or annular shells are provided with circular shrouds Se encircling the tips of each oi the ian bladesin closely coupled relation, which may be provided in a convenient and simple manner as by turning in and back the outer edges of the side walls to iorm an air foil entry as described with reference to the iirst embodiment. The circular shrouds 39 separate the inport di of a greater area than the intake area of each fan providing easy unrestricted entrance of air advanced axially into the housing. In this manner the full volumetric eiciency of each fan is lobtained in operation.

chambers d2 which are disposed concentrically.

with reference to the propeller type fans to receive the air which is thrown centrifugally theretrom at high velocity. IIhe air collector chambers d2 are formed so as to provide suiilcient space for expansion of the entrapped air axially of the housing, and the smooth annular shape of the chamber encourages the rotation of the air which is collected under pressure in the collector chamber where it is stored with its potential and kinetic energy as in a. reservoir until released.

The arrangement of this annular air collector chamber is also such that it provides for eiiicient delivery of the collected air because, being concentric with reference to the propeller fan, outlet ports may be opened tangentially therefrom at a number of points to deliver the air directly toward the points where the air is to be utilized, as shown in Fig. 1. With such a blower unit it is not necessary to pass the air through a long conduit having many corners and curves which dissipate the energy of the air. Although only two delivery conduits 43 areshown in Fig. 1, it is to be runderstood that more of such outlets may be provided conveniently aroundthe outer periphery of the collector chamber for delivering airdirectly toward the point Awhere it is to be utilized with a minimum loss of energy.

The arrangement of two propeller fans in opposite or reversed relation on a drive shaft for inducing two air streams to iiow in opposite directions causes the end thrusts on the shaft to be balanced and in this manner end thrust bearing friction is eliminated reducing the power demand which also improves the eflciency of our air impeller device.

To assemble the electric motor in the unit it is conveniently inserted through either air inlet port in either end of the double housing where, byclamping the two baiiles I3 together with bolts, passing through suitable holes in central partition wall, the motor is resiliently but firmly clamped in a central concentric position as shown with its double ended shaft extending axially in the housing. In this convenient assembly the electric motor is also insulated electrically and acoustically from the housing. The propeller ing-the of the 'drive shaft and because of the air inlet ports being larger in diameter than the fans, the direct insertion of the fans is accomplished without the necessity of removing shroud ring anges or the like and the construction is also simplified.

The arrangement of the electric motor between two propeller fans drawing air into opposite ends of the housing provides a conveniently motivated unit which is very compact.

Because of the supplementary cooling fins 38 on motor and the thorough and efiicient ventilation of the electric motor accomplished by air swirling into and around the inside space in each baille ring, and also because of` the low power requirements'for moving and delivering a given volume of air, in our air impelling arrangement, a small motor may be used in our unit thereby further contributing to the light weight and compactness thereof.

In Fig. 4 is shown a similar view of another embodiment of our improved double blower unit. In this improved double blower unit the construction is similar except that baille structures yare provided in which the cylindrical intermediate portionl I3 has been shortened to support the annular bafiie surfaces I5 at a position spaced further in from the shroud ring 39. This arrangement is made especially to accommodate composite propeller fans Bnl having a centrifugal air throwing vane 63 turned out on the heel of each blade. The edges of the centrifugal vanes 63 on the discharge side of the fan are substantially straight and disposed substantially parallel to the plane of rotation of the fan and cooperate closely with the annular baille surface i5 as the fan rotates. The composite fans 6l utilized are preferably of a construction disclosed in greater detail in our copending patent application Serial Number 157,274 led August 4, 1937, issued as Patent No. 2,176,325'on October 17, 1939.

The two composite propeller fans used in this unit are preferably of similar capacity, but are of reversed or opposing conformation in order to draw two streams of air axially into opposite ends ofthe unit, and to balance axial thrusts on the shaft and eliminate end thrust bearing friction, as in the previous embodiment. When used in our improved double blower unit assembly our improved composite propeller fans tend to accentuate or augment the tendency of the fans to throw air radially. The special composite fans when so used cooperate functionally with the improved arrangement of thecircular battle, shroud and the concentric air collecting chamber, previously described, to collect a greater volume of air at a higher pressure and to still further improve the efiiciency of our air impelling apparatus.

Substantially all the advantages previously described, excepting those relating to the mounting and insulation ofthe electric motor, may be utilized in air impeller arrangements where the air impellervis driven from an external source ofpower as well as a combined motor.

In-operation the fan creates an axial flow of air irito its region to impact onto the baille disc with resulting rotative and radial ilow velocities. When this air is encounteredby the inner ends of the trailing vanes or tip-up portions of the blades it soon gains high velocity tangential components from being held in these passages for a `period to emerge with a radial pressure and force into the collector chamber and by preservdischarge flow direction. during exit fans 31 are then secured on the opposite ends.

through the tangential outlet ports, minimum loss of kinetic energy is caused.

It is apparent that within the scope of our invention, modifications and different arrangements may be made other than herein disclosed, and the present disclosure is illustrative merely, the invention comprehending variations thereof.

l. In a fluid impelling apparatus the combination of, a housing having a substantially cylindrical peripheral wall, one edge of said wall being turned in and back to define a circular entry port substantially concentric to the axis of the housing, a flanged radial wall of circular or disc like conformation forming a confining element of said housing and supporting means rfor an electric motor, a motor receiving aperture in the center of said radial wall, an electric motor, means mounting said motor in said aperture with the shaft of the motor extending concentrically toward said circular entry port, a propeller fan operatively secured on the shaft and disposed adjacent the entry port for drawing air through the circular entry port into said housing, bai'iie means of generally annular conformation concentrically secured to said flanged radial wall and having a radial portion projecting therefrom adjacent the discharge face of the fan which in combination with the turned in walls around the entry port provides an open air receiving port through which high velocity air advanced by the outer portion of the fan blades is caused to enter, and said radial baille means cooperating with the housing walls to form a smooth annular collector chamber in which such high velocity air is received and encouraged to rotate cooperatively with the fan, and an air delivery port opening from said collector chamber.

2. A fluid impelling device comprising, a housing of substantially annular conformation, the outer wall of said housing having an edge at one end turned back and in to form a circular entry port, a radial supporting Wall in said housing for closing the other end, said radial wall having a central aperture with an offset flange disposed as to provide a motor mounting base concentrically positioned with respect to said housing, an electric motor with central radial iin extending from the central section of its frame, suitable insulation means encircling said n, a clamping ring with suitable attaching means to clamp said insulation means for securing said motor to said wall in concentric relation to entry port, a propeller fan with hub for attachment to motor shaft, said fan having an overall diameter less than that of the entry port, and said fan being mounted for rotatable operation on the motor shaft and disposed to operate in a position relative to the entry port such that the intake. area of the fan shall be outside the entry port and the discharge area within the entry port thus isolating the intake area of the fan from the discharge area of said fan, and discharge outlet means in said outer wall of housing facilitating radial delivery of air advanced therein.

3. In combination in a compact iluid impelling and collecting device, a propeller fan having a rotatable hub and designed to induce a flow of fluid axially into its rotative plane when in rotation, motive means for driving said fan, a housing of substantially annular conformation with suitable entry port means larger in diameter than the fan, and closely coupled about its periphery to isolate the intake area from the discharge area thereof, said housing likewise being so conformed aseaaee as to provide an open sided annular chamber disposed to receive uid advanced from said discharge area oi' ian, a supplementalnwall formed in said housing and so conformed and disposed as to provide an enclosed annular chamber for the accumulation and axial expansion or duid advanced therein, mounting means in said housing whereby said motive driving means may be concentrically supported therein, radial heme means closely coupled and concentrically disposed relative to central discharge face of said fan and having 'a portion of its radial face extending in spaced relation adjacent the high ve1 locity discharge area of said fan to form chamber means between the outer wall supporting the motive means and said baiile means to' entrap duid within said annular chamber, where such duid is encouraged to obtain a maximum rotative component and suitable dlscharge'port conduit means connecting from the peripheral wall of said chamber in a substantially tangential direction in the direction of rotation of the fan to discharge collected iiuid from the chamber in a substantially tangential direction for ultimate delivery to points desired and with a minimum loss of kinetic energy.

d. A uid impelling device comprising, a housing having side walls of a substantially annular conformation, an electric motor having a shaft extending in opposite directions therefrom, a central partition wall centrally apertured for dividing the housing and mounting said motor concentrically in said housing, propeller fans of similar capacity the motor shaft, said fans being of reversed or opposite pitch so that as the motor drives the fans air is drawn axially into opposite ends of said housing with balanced end thrust on the shaft for minimum bearing friction, the edges of the annular side walls of the housing being turned in adjacent the tips of the fan blades for forming circular air inlet ports of greater area than the intake area of each fan and closely coupling around the tips of the fan blades for operatively separating the intake area from the discharge area of each fan, a baiiie member of generally annular conformation concentrically secured to each opposite side of said central partition wall, each baie member projecting toward the fan in the adjacent end of the housing and having a radial baille surface supported adjacent the discharge face of each fan respectively, said baffle means in combination with the housing wallsforming an annular air collector chamber adjacent the outer portions of the blades of each fan with an annular air receiving port through which high velocity air advanced by the outer portions of the fan blades is caused to enter, and an air delivery port opening from each collector chamber.

5. A uid impelling device comprising the combination set forth in claim 4, in which said bame members are clamped to said partition wall by bolts and have cooperative flanges forming a pocket, a circumferential n projecting from the axial center of said motor into said pocket, and resilient means clamped in said pocket between said anges for securing said motor rmly but resiliently.

6. A fluid impelling device comprising. a housg having side walls of a substantially annular conformation, an electric motor having a shaft extending in opposite directions therefrom, means mounting said motor concenti'lcally in said housing, propeller fans oi' similar capacity disposed disposed on each extended end ofv on each extended end oi the motor shaft, said fans being of reversed or opposite pitch so that as the motor drives the impellers air is drawn axially into opposite ends of said housing with balanced end thrust on the shaft for minimum bearing friction, the edges oi the annular side walls of the housing being turned in adjacent the tips of the fan blades for partially enclosing separate annulmair collector chambers for receiving air thrown from the high velocity portions of the fans and also forming circular air inlet ports of greater area than the intake area oi' each ian while also forming circular shrouds operatively separating the intake area from the discharge area of each fan, centrifugal air throwing varies on the heels oi the blades of each ian, said venes extending from the plane of rotation of each ian withthe extended edges substantially parallel to the plane of rotation on the discharge side oi each ran, a baiile member disposed adjacent the discharge side of each fan in the form of a radial wall adjacent the extended edges of the centrifugal vanes for further enclosing said collector chambers and directing advanced .air to enter said collector chambers and become entrapped therein, and delivery discharge outlets opening from said chambers.,

'7. in a uid impelling device the combination set forth in claim 6 in which the means for mounting said motor comprises a centrally apertured partition wall centrally disposed in the housing, and the bame members being clamped to opposite sides thereof and having cooperative portions clamping together as the bame members are clamped to the partition wall.

8. In combination in centrifugal iiuid impelling apparatus, a propeller fan rotatably mounted. motive means for ali duid advanced thereby to iiow in a substantially re dial direction at high velocity, said baille means also dening at its peripheral extremity the margin of an open air receiving port, a housing oi substantially cylindrical conformation suitably enclosing the fan tips and forming an air thereof, the margin of said housing being conformed to dene an entry port encircling and closely coupling the tips of fan blades at a point representing the extremities of the intake face the intake area means being also positioned in spaced relation to the radial enclosing wall of the cylindrical housing to provide suitable expansion chamber capacity compactly arranged within said housing the uid collected and suitable outlet port means in the periphery of collector chamber to permit discharge of fluid thus collected to be conducted to point of desired usage.

9. In combination in air impelling apparatus, a rotatively mounted propeller fan for inducing an axial flow of relatively low velocity air into its rotative plane and advancing such air therefrom, shroud means deiinins an entry port closely coupling with the entry area of said fan and separating the intake area from the discharge area thereof, a radial baille wall, said shroud means and bale wall being shaped and positioned to enclose a chamber of annular conformation concentrically disposed with referencerto the fan. said chamber being so conformed that the radial 'wall is disposed adjacent to and closely coupling the discharge face of said fan to redirect axially advanced air in a radial direction toward fan blade outer extremities and simultaneously preventing such air from reentering the central area of the discharge face of said fan, said radial bame wall having its peripheral extremity located at a diameter approximating that of the propeller fan to cause all air advanced thereby to iiow from the high velocity portions of the blades, an annular open air receiving port in said collecting chamber deilned by the peripheral margin of said radial wall and the extremity of said shroud means whereby only air of high velocity is induced to enter the concentrically disposed annular air collecting chamber where it may expand in axial relation as well as radially, and suitable delivery port means associated with said annular collector chamber and opening in various directions so that air collected therein and cooperatively rotated with the fan may be discharged directly to various points of utilization with a minimum loss of the kinetic energy of such delivered air.

10. A fluid impelling apparatus comprising, a housing having side walls of a substantially annular conformation, a central partition wall centrally apertured for dividing the housing, a shaft, bearing means for rotatably mounting the shaft axially in said housing and extending through the aperture in said partition wall, propeller fans of similar capacity disposed on said shaft on opposite side of said central partition wall, said fans being of reversed or opposite pitch so that when shaft is rotated air is drawn axially into opposite ends by said housing with balanced end thrust' on theshaft for minimum bearing friction, the edges of the annular side walls of the housing being turned in adjacent the tips of the fan blades for forming circular air inlet ports adjacent the intake area oi each fan and closely coupling arolmd the 'tips of the fan blades for operatively separating the intake area from the discharge area of each fan, a baille member of generally annular conformation concentrically secured to each opposite side of said central partition wall, each baille member projecting toward the fan in the adjacent end of the housing and having a radially extending bailiesuriaoe supported adjacent the discharge face ofeach fan respectively, said baille means in combination with the housing walls forming an annular air collector chamber adjacent the outer portions of the blades of each fan with an annular air receiving port through which high velocity air advanced by the outer portions of the fan blades` is caused to enter, and air delivery port means for discharge of such air to point of usage.

11. In combination in iiuid impelling apparatus, a housing of substantially cylindrical conformation with one radial wall for enclosing one end, said radial wall provided with motive mounting ,means concentrically positioned, impeller means comprising propeller type ian operatively mounted for advancing iiuid therein, shroud means associated with the housing at opposite end from radial wall and also forming an entry port, said shroud so disposed to separate entry face of fan from discharge face thereof, a second radial baille wall having a peripheral diameter substantially equivalent to the fan diameter and so disposed adjacent the discharge face of said fan in closely coupled relation to cooperate with shroud in defining a restricted open air receiving port providing for the fluid advanced by the fan to be directed into the housing at high velocity and also deiining an annular collecting chamber of smooth annular conformation encircling the extremities of the fan and providing suitable expansion capacity within said housing between the radial conilning wall and said second radial baille wall, said expansion area being disposed in axial relation to the impeller for axial expansion rather than radial expansion of fluid, and collector chamber discharge port means disposed to provide delivery of advanced :duid in a substantially tangential direction relative to impeller.

. WALTER H. BRE'IZLAFF.

CHARLES P. GRIMES.