US2088312A - Air circulation - Google Patents

Description

Ju ly 27,jl937. M. WEBER 2,088,312

AIR CIRCULATION I v Filed Aug. 28, 1933 3 Sheets-Sheet 1 Patented July 27, 1937 UNITED STATES PATENT OFFICE 3 Claims.

The present invention pertains to the circulation of air in a. room or other inclosure and its object is to provide an improved, novel and highly eflicient method of air circulation whereby substantially all of the air in the room in which the method is carried out or practiced is caused to rotate helically about a central, horizontal axis in order to mix together the nitrogen, oxygen, carbon dioxide and other contents of the air and thus obtain uniformity of the air throughout all portions of the room or inclosure. In general, this method consists in directing across the room and above head height a central stream of high velocity, helically moving air and discharging a plurality of high velocity air streams in such manner and form that they flow helically around the central stream of helically moving .air and cause all the surrounding air in the room or inclosure to revolve and move in harmony therewith.

The invention consists in the method which is hereinafter described in detail and set forth in the accompanying claims.

In the drawings which accompany and form a part of the present specification or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is a view, partly in side elevation and partly in section, of a fan apparatus for producing the air streams of the improved method;

Figure 2 is a fragmentary perspective showing by arrows the manner in which the air streams emanating from the fan apparatus operate helically to revolve the surrounding air in the room in which the apparatus is located;

Figure 3 is a front view of one of the blades of the wheel of the fan apparatus; and

Figures 4, 5, 6, 7, 8 and 9 are sections taken re spectively on the lines 4-4, 5-5, 6-6, 1-1, 8-8 and 9-9 of Figure 4.

The apparatus shown in the drawings represents one means or structure for carrying out the method which forms the subject matter of the invention. This. apparatus is in the form of a unit which is suspended from the ceiling of the room or inclosure in which the method is to be practiced. As shown in Figures 1 and 2 of the drawings. the apparatus comprises a fan wheel I0 and is spaced from one of the end walls of the room a distance substantially equal to one-fourth the length of the room. The fan wheel I0 is in the form of a one-piece casting and comprises an elongated, sleeve-like huh II and five radially extending blades l2. The rear end of the hub II is journalled in a bearing l3 on a platform ll so that the fan wheel is rotatable on a horizontal axis. The platform It is suspended from the ceiling of the room by straps i5 and the bearing I3 is positioned on the platform so that the fan wheel is carried above head height and is spaced substantially equidistantly from the side walls 5 of the room. In practice it has been found that the method may best be practiced by positioning the fan wheel at an elevation of approximately eight feet from the floor of the room in which the air is to be circulated.

In addition to the wheel Hi, the apparatus comprises a centrifugal blower l6. This blower, as shown in Figure 1, is located on a platform I1 and is driven by an electric motor It. The

platform I! is suspended from the ceiling of the 10 room by the straps l5 and is positioned above the platform l4 and in close proximity to the ceiling. The electric motor I8 is mounted on the platform H in front of the blower l6 and has the rear end of the armature shaft thereof connected to the 20 blowers rotor (not shown). The blower embodies a central inlet (also not shown) in one of the side walls of the casing thereof and has a conduit l9 connected to the casing outlet. This conduit extends downwardly from the blower l6 and is provided at the lower end thereof with a fixed or non-rotatable discharge tube 20. The latter ex-. tends longitudinally through the central portion of the hub H of the fan wheel Ill and is arranged so that the air compressed by the blower and delivered to the conduit I9 is discharged forwardly from the center of the fan wheel in the form of 'a stream which is shown by dotted lines in Figures 1 and 2 of the drawings and is substantially of uniform thickness from one end thereof to the other. A helical rib 2| is formed on the inner periphery of the discharge tube. 20 and operates to cause the air stream emanating from the tube to flow spirally as shown by dotted lines in Figures 1 and2. During drive of the blower l6 4 by the electric motor l8, air is drawn into the blower casing by the rotor of the blower casing into the conduit l9. From the conduit I9, the compressed air flows to the tube 20 from whence it is discharged in the form of a central stream which flows spirally in a forward direction from the center of the fan wheel Ill. The blower is preferably driven at such a speed and so constructed that the stream of air emanating from the tube 20 flows without substantial diminution in velocity to the far end of the room. The tube 20 is of 'such length that the central air stream is practically of the same thickness throughout its entire length. a

The fan wheel I0 is driven by the electric u motor l8 through the medium of anlendless belt 22. This belt extends around a pulley 23 on the front end of the armature shaft of the motor and a pulley 24 on the hub ll of the fan wheel. The blades [2 of the fan wheel embody pressure faces 25 at the front thereof and suction faces 26 at the back and are angled with respect to the plane of rotation of the fan wheel so that the suction faces operate to draw forwardly the air in back of the fan wheel into contact with the pressure faces 25 which efi'ect air propulsion in front of the wheel. The pressure faces are in the form of longitudinally or helically twisted, fiat surfaces and at the root or inner ends of the blades extend rearwardly at an angle of 42 with respect to the plane of rotation of the wheel as shown in Figure 4. At one-sixth of the distance from the inner ends of the blades to the outer ends, the pressure faces 25 are inclined or angled at 40 with respect to the plane of rotation of the wheel as shown in Figure 5. At one-third of the distance from the inner ends of the blades to the outer ends, the pressure faces are inclined or angled at 37V with respect to the plane of rotation as shown in Figure 6. Halfway between the inner and outer ends of the blades, the pressure faces extend rearwardly at an angle of 35 with I respect to the plane of rotation of the wheel as shown in Figure '7. At two-thirds of the way from the inner ends of the blades to the outer ends, the pressure faces; extend rearwardly at an angle of 32% with respect to the plane of rotation as shown in Figure 8. At five-sixths of the way from the inner ends of the blades to the outer ends, the pressure faces extend rearwardly at an angle of 30 with respect to the plane of rotation as shown in Figure 9. By reason of the fact that the pressure faces of the blades are in the form of helically twisted, fiat surfaces and decrease in pitch at the rate of 2% every sixth of the distance from the inner ends of the blades to the outer ends, each blade during rotation of the fan wheel, produces a stream of air which fiows spirally around the central stream emanating from the tube 20. Inasmuch as there are five blades on the wheel I, five air streams are projected by the fan wheel around the central air stream. These five streams as they flow from the fan wheel l0 to the fan end wall of the room in which the apparatus is disposed, producea cyclonic effect within the room whereby the surrounding air is revolved in harmony therewith as shown by arrows in Figure 2. For ventilating a room of large size,- such as one fifty feet long and thirty feet wide, a twenty inch, five bladed fan wheel is preferably employed. At a preferred speed of 1800 revolutions per minute, the five air streams produced by the bladesof the wheel flow at an average velocity of 2770 feet per minute and 5550 cubic feet of air per minute are displaced. Because of the specific construction and formation of the blades, the five air streams travel the full length of the room without merging into the surrounding air, and maintain throughout their course of movement their helical or spiral flow around the centralair stream. The leading edges of the blades I2 are substantially straight, as shown in Figure 3, and the outer or tip ends of the blades are rounded and are substantially semicircular in conformation. The central portions of the blades are slightly less than one-half the. length of the blades and the trailing edges are convex. The suction faces 26 are convex, as indicated in Figures 4, 5, 6, 7, 8 and 9 of the drawings, and the blades are of maximum thickness near the leading edges thereof. The suction faces of the blades are sharply curved adjacent the leading edges and the portions thereof adjacent the trailing edges of the blades are more gradually curved. The shape or conformation of the suction faces of the blades is such that during rotation of the fan wheel all of the air in back of the fan wheel, that is, adjacent the near end of the room, is drawn forwardly at comparatively low velocity into contact with the pressure faces 25. Because of the specific shape and curvature of the pressure faces of the blades, the five air streams produced by the blades during rotation of the wheel l0 by the electric motor l8 pulsate as they flow helically around the central air stream. The pulsations of the five helical air streams serve to set in motion the surrounding air in the room andthus cause the latter to fiow around the room in harmony with the air streams. The pulsations are attributable to the fact that the air in the five helical streams is compressed without restriction and hence at intervals along the course of fiow of the streams portions of the air flow outwardly. The outwardly and rearwardly extending curled lines in Figures 1 and 2 of the drawings are intended to represent the pulsations or fluctuations in pressure. In practice it has been found that with the aforesaid twenty inch, five bladed fan. wheel there are twelve pulsations per minute when the wheel is rotated at 1800 revolutions per minute and that these pulsations occur at approximately every six feet along the courseof travel of the air streams. As the five air streams created by the pressure faces of the blades leave the fan wheel, the pressure of the air in the streams builds up in increasing amount until at approximately six feet from the wheel a portion of the air leaves the streams and flows outwardly and helically in a rearward direction as shown in the drawings. The air remaining in the streams continues forwardly and, as the pressure again builds, a portion of the air flows outwardly and causes another pulsation. This action of the air in the streams continues throughout the entire course of the air streams. The air which leaves the air streams and forms the pulsating eflect flows helicallyand rearwardly and, as previously pointed out, sets in motion the surrounding air, thus causing the latter to move around the room in harmony with the high velocity air streams air flows through the tube and is discharged horizontally across the room in stream form. As the compressed air flows through the tube it is subjected to the action of the helical rib 2| on theinner periphery of the tube and is caused to fiow helically. As previously pointed out, the

.central air stream emanating from the tube, be-

cause of the velocity of the air and shape and construction of the tube, fiows from the fan wheel III to the far end wall of the room without substantial change in form. During rotation of the fan wheel III by the electric motor "I, the air in back of the fan wheel is drawn uniformly and at low velocity forwardly into contact with the pressure faces of the blades by the suction faces 26 and is projected in the form of five streams which flow helically around the central air stream emanating from the tube 20. These five air streams pulsate or flow in gusher form and 5 produce a cyclonic movement of the surrounding air in the room whereby all of the various ingredients of the air, such as the nitrogen, oxygen and carbon dioxide, are thoroughly mixed. The

pulsating or gusher character of the five helical 10 air streams emanating from the blades sets the surrounding air in motion and causes the air to flow in harmony with the streams. The central air stream gives force and impetus vto the five, blade-produced air streams and causes them 15 to flow without substantial diminution in velocity to the wall at the far end of the room. The air streams, as' they impinge against the wall at the far end of the room, are deflected inall directions. Byreason of the fact that the fan 20 wheel l and tube 20 are located at approximately an elevation of eight feet from. the floor, the occupants of the room are not subjected to direct draft. g

The herein described method of air circulation 25 may be carried out by a fanwheel such as that shown and described in Letters Patent of the United States'No. 1,933,948 granted to me November' '7, 1933 or by apparatus other than that herein disclosed and contemplates delivering a 30 central, helically moving stream of air across a room or inclosure above head height and directing a plurality of high velocity air streams,

- around the central stream in a pulsating manner so as to produce a cyclonic eflfect within the room whereby the surrounding air is caused to rotate in harmony therewith and the various constituentsor component parts of the air are thoroughly mixed together.

Having thus'described the invention, what I claim as new and desire to secure by Letters Patent, is: i

1. That improvement in circulating air in a room which consists in discharging substantially horizontally across the room a central stream of air and at the same time propelled around said central stream a plurality of entwining, helically moving streams of air at such velocity and in suflicient amount to cause substantially all the air in the room to revolve and move in harmony therewith.

2. That improvement in circulating air in a room which consists in discharging substantially horizontally across the room a central stream of helically moving air and at the same time propelling around the stream a plurality of entwining, helically moving streams of air at such veloc-' ity and in sufficient amount to cause substantially all the surrounding air in the room to revolve and move in'harmony therewith.

3. That improvement in circulating air in a room which consists in discharging horizontally across a room a central stream of air and at the same time propelling around said central stream30 more than two entwining, helically moving streams of air.

MAX WEBER.

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