US3150821A

US3150821A - Fluid flow machine having parallel rotors

Info

Publication number: US3150821A
Application number: US221617A
Authority: US
Inventors: Laing Nikolaus
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-09-05
Filing date: 1962-09-05
Publication date: 1964-09-29
Anticipated expiration: 1981-09-29

Description

Sept. 29, 1964 N. LAING 3,150,821

FLUID FLOW MACHINE HAVING PARALLEL ROTORS Filed Sept. 5, 1962 2 Sheets-Sheet l m I L 7 \I\ 7 4.9

4f- 7 7' I j y Mi A INVENTOR I NlkO EL/ wlanigzu KM,

ATTORNEYS Sept. 29, 1964 N. LAING FLUID FLOW MACHINE HAVING PARALLEL ROTORS Filed Sept. 5, 1962 2 Sheets-Sheet 2 United States Patent 3,150,821 FLUID FLGW MAfIHlNE HAVING PARALLEL ROTURS Nikolaus Laing, Roseuhergstrasse 24A, Stuttgart, Germany Filed Sept. 5, N62, Ser. No. 221,617 Claims. (Cl. 230-117) This invention relates to a fiuid flow machine having parallel rotors and more particularly to a fluid flow machine of the cross-flow type having cylindrically bladed rotors and guide means associated with each of the rotors to guide air through the path of the rotating blades into the rotors and through the path of the rotating blades out of the rotors. This application is a continuation-in-part of copending application Serial No. 671,114, filed July 5, 1957, now abandoned.

The invention concerns more especially a flow machine of the type described comp-rising a plurality of rotors arranged side by side with their axes parallel and associated with guide means whereby all of the air passing through each of the rotors is discharged in the same general direction.

Fluid flow machines in the form of axial flow fans often used as ventilating fans are not capable of utilizing the complete cross-sectional area of the fan because the center of the fan is usually taken up by a motor which is used to rotate the fan blades. Such fans are often mounted in rectangular housings in order that the housing might be inserted in a wall opening or in a window frame. Axial flow fans when so mounted are not able to provide air flow through the complete opening since the fan itself is circular and the area of the corners of the housing beyond the periphery of the fan are closed in order that the housing might fit in the window opening.

Centrifugal-type fans are likewise inappropriate for use as a wall fan since ducting must be provided for the inflow of air into the rotor thus preventing complete utilization of the wall opening.

It is, therefore, an object of this invention to provide for a cross-flow type fluid flow machine of the type described which may, for example, be inserted in a wall opening or window to make effective use of the complete cross-sectional area of the opening or Window.

Broadly, the invention contemplates having a plurality of bladed cylindrical rotors having guide means associated therewith such that in operation of the machine air is caused to flow into the rotor through the path of the rotating blades and out of the rotor through the path of the rotating blades. Preferably the guide means are such to form a cylindrical fluid vortex approximating a Rankine vortex with the vortex having its region of low static pressure parallel to the rotor axis and having its core interpenetrating the blade ring in order to guide flow of air through the rotor. The rotors are arranged with their axes parallel with each other. The guide means may include guide members movable between operative and inoperative positions wherein the guide members are effective to close the aperture or window frame.

Preferred embodiments of my invention are illustrated diagrammatically in the accompanying drawings in which,

FIG. 1 is a front view of a flow unit adapted to be inserted in a window or wall opening;

FIG. 2 is an enlarged cross-sectional view of the unit of FIG. 1 taken along lines II-II;

FIG. 3 is an enlarged cross-sectional view of a different embodiment of the flow unit a shown in FIG. 2; and

FIG. 4 is a cross-sectional view of an electric motor suitable for driving a flow unit according to the invention.

Referring to the drawings in which the flow machine is 3,150,821 Patented Sept. 29, 1964 shown as a fan, the fan unit of FIGS. 1 and 2 comprises a rectangular frame 1 suitable for placement in an aperture in a wall or window. The fan comprises four

similar rotors

2, 3, 4, and 5, mounted horizontally one above another with their axes parallel and all contained in the same vertical plane. Each rotor is divided into two equal sections such as the sections of rotor 2 designated 2a and 2b. A central vertical pillar 6 extends between upper and lower horizontal members of the frame 1 and carries the driving means 7 for the rotors 2-5 which means are not shown in detail. Each driving means supports a pair of rotor sections and is situated intermediate those sections. A form of motor suitable for driving the rotors is shown in FIG. 4.

Each rotor section, for example section 2a, comprises rotor blades 8 mounted parallel to the rotor axis with inner and outer edges of the blades lying on cylindrical envelopes, the blades being concave facin the direction of rotation and having their outer edges leading their inner edges. The driving means or a part rotating therewith substantially closes one end of the rotor section 2a. The other end of the rotor section 2a, where the blades are preferably interconnected and rigidified by a ring not shown, lies adjacent a vertical member of the frame 1 and is separated therefrom by only a working clearance (which for clarity is shown magnified in the figure). Thus, this end of the rotor section is also substantially closed. Rotation of the rotor takes place in the direction indicated 'by the arrow iii.

A series of guide members designated generally 14 extend horizontally with constant cross-section between the vertical members of the frame 1, interrupted only by the pillar 6. The rotors 2-5 are each located between a pair of guide members 14, one above the rotor and one below, which members present upper and

lower guide walls

15 and 16 thereto. The

guide walls

15 and 16 are similar for each rotor and therefore only one pair will be described.

The upper and lower guide walls 15 and 1d cooperating with the rotor section 2a provide portions 15a and 15a converging towards the rotor on one side thereof and defining therewith an entry region 17. On the other side of the rotor, the

walls

15 and 16 diverge therefrom and define an exit region 18. The diverging portion of the upper wall 15, which is designated 15b, has a radius of curvature increasing monotonically from the line of nearest approach to the rotor. The lower wall 1a which has a first guide surface 16a extending from one side of the frame towards the rotor and a second guide surface which extends from the rotor to the opposite side of the frame and has in addition a slightly concave portion 1612 which converges with the rotor in the direction of rotor rotation to the line of nearest approach. The wall 16, thereafter, extends towards the exit region and breaks sharply into a more strongly divergent portion 160. The wall 16 cooperating with each of the

rotors

2, 3 and 4- meets the wall 15 cooperating respectively with the

rotors

3, 4 and 5 at an acute angle both at the entry and at the exit side of the unit. Thus, the fan unit draws air from virtually the whole area of the frame 1, and also discharges over the whole area.

The guide walls and the angles and curvature of the rotor blades 3 are so arranged that in operation the rotor 2 and the guide wall 16 form and stabilize an approximately cylindrical vortex, including a field region with a velocity profile approximating that of a Rankine vortex and a core region eccentric to the rotor axis (which core region is indicated at V). The vortex formed induces a major part of the throughput to pass through the blades where they have a component of velocity in a direction opposite to the main direction of the flow within the rotor (shown by the arrow A). That part of the wall 16 which chiefly influences flow through the rotor (the part 16b) extends over only a small arc thereof so that the stream tubes of the throughput nearest the vortex core (which tubes are indicated at MF) are turned through an angle 'at least 90 in passing through the rotor and the velocity profile at the second entrance to the rotor blades has the character of the velocity profile of a Rankine vortex. The major part of the throughput is associated with the flow tubes MP.

A ventilating fan for use in the wall or window of a room is limited as to peripheral speed since too great a speed will give rise to objectionable noise. Motor speed will normally be a design datum and in conjunction with the limitations on peripheral speed will drastically restrict the rotor diameter. Flow therefore necessarily takes place under conditions of low Reynolds numbers where conventional type fans are inefficient. The features just described lead to a great improvement in efliciency under such conditions, over what has hitherto been regarded as acceptable. The arrangement of the rotors side by side with their axes parallel enables any desired throughput to be handled despite the restrictions on rotor diameter. Thus a fan unit according to the present invention can be both more compact and more silent than a unit of equivalent throughput belonging to the types hitherto in common use, such as an axial flow fan unit.

The fan unit just described has the further advantage over axial fans hitherto commonly used for ventilation in that it is little effected by back pressure, such as might be produced by a wind blowing against the outlet side of the unit, or alternatively, by the suction necessary to bring fresh air into a closed room where the air must pass under doors and through like restricted passages.

The fan unit of FIG. 3 includes two similar rotors 3t and 31 mounted one above the other with, their axes horizontal within a frame designated generally 32. Shafts 30a and 31a driven by means not shown support the rotor, but apart from these shafts, the interiors of the rotors are clear of obstruction. Each rotor comprises longitudinally extending blades 33 and rotates in the direction of the arrow 34.

A pair of

similar guide members

35 and 36 extend the length of the rotors 3t) and 31 with constant cross-section with one member above each rotor. Both members are each pivoted about the axes of the rotors on plates 39b and 31b secured to the ends of the members and extending at right angles to those axes. The lower surface 35a of the upper guide member 35 and the upper surface 36a of the lower guide member 36 provide in the full-line positions of those members, guide walls to guide air twice through the path of the rotating blades of the upper rotor 30. Similar guide walls for the lower rotor 31 are provided by the lower surface 36b of the guide member 35 in its full-line position and the upper surface 37 of a fixed lower member of the frame 32. The lower guide walls of the

rotors

30 and 31 include portions 36c and 37a on the exit side of the rotor which converge therewith in the direction of rotation. In operation of the fan unit, the interaction of the rotors and their respective guide Walls sets up a Rankine vortex in each rotor having a core V penetrating the blade envelopes of the rotor, and flow takes place in the general manner indicated by the flow lines F. Air flow in each rotor will be seen to be generally similar to that of the fan unit of FIGS. 1 and 2, the description of which should be referred to in this connection.

With the

guide members

35 and 36 in the full-line positions shown, their upper surfaces 35b and 36a extend downwardly and well outward of the exterior surface 38 of the frame 32. Rain falling on these surfaces will be deflected well clear of the

rotors

30 and 31. The

guide members

35 and 36 can be pivoted to the dotted positions shown, in which case they close the aperture through the frame 32 against draughts and the weather. Some regulation of the fan unit can be achieved by slight angular movement of the

guide members

35 and 36 from the fullline positions. It should be noted that in a fan unit as shown in FIG. 3 designed on the principles above referred to, power consumption decreases as the throughput decreases. Thus regulation of the throughput can be effected economically without need to regulate the driving motor.

The

guide members

35 and 36 can be designed to pivot from closed to operative position under pressure produced by rotation of the rotors and against the bias of their own weight which, when the rotors are stopped, returns the

members

35 and 36 to closed position.

FIG. 4 shows an electric motor designed for continuous running and specifically adapted to drive a pair of

coaxial rotor sections

40 and 41 extending to either side of the motor. A stator unit designated generally 42 is supported by a pillar 43 and comprises laminations 44a and 4412 with a common winding 45 thereon. Axially extending flanges 46 and 47 project from

end discs

48 and 49. The discs mount the

rotor sections

40 and 41 and substantially close their adjacent ends. The flanges 46 and 47 surround the stator laminations 44 and carry laminations 5t) and 51 cooperating therewith. A tubular spindle 52 interconnects the

end discs

48 and 49 and runs in bearings 53 mounted within a tube 54 rigid with the stator unit 42. A support 55 terminating in a rubber ball is adapted to rest against some adjacent part to give additional support to the motor.

It is not essential in a flow machine according to the invention for the guide means for each rotor to be such as to set up a Rankine vortex therein nor for the interior of each rotor to be clear of stationary obstructions, though these features have been common to the embodiments described with reference to the drawings. It is possible to provide guide bodies within the rotors to guide the flow through the rotor and through the path of the rotating blades. Various arrangements of such guide bodies are disclosed in application Serial No. 671,114. The motor of FIG. 4 provides a convenient way of supporting such guide bodies. Thus, guide bodies in the two rotor sections may be connected by a shaft extending through the hollow spindle 52.

I claim:

1. A fan unit comprising a shallow open vertical frame, at least two similar hollow horizontally extending cylindrical bladed rotors vertically aligned within said frame and extending over a major cross-sectional area of said frame, means to rotate said rotors, a first and a second guide wall extending the length of said rotors positioned adjacent each said rotor and on opposite sides thereof with said first wall having a first guide surface extending in one direction from one side of said frame substantially toward a rotor and a second surface extending substantially away from the rotor to the opposite side of said frame and with at least one first guide wall adjacent one rotor joining at both sides'of said frame with a second guide wall of an adjacent rotor; said first guide wall forming with its adjacent rotor when rotated a fluid vortex having a core eccentric of the rotor axis and interpenetrating the rotor blades adjacent said first guide wall to guide air along said first and second surfaces from one side of the frame through the path of the rotating blades into the interior of the rotor and thence out through the path of the rotating blades to the other side of the frame whereby air is caused to flow through a major part of said frame. 7

2. A unit according to claim 1 wherein some of said guide walls include rotatable guide members extending in an open position beyond said unit; said members when rotated to a closed position covering a side of said unit.

3. A unit according to claim 2 wherein said guide members are pivotally mounted whereby the weight of the member urges said member to a closed position when said unit is not operating and air pressure acts on said 3,1 5 member to urge it to an open position when said machine is operating.

4. A fan unit according to claim 1 wherein each said rotor is divided along its length into a pair of sections, and having in addition a vertical member extending intermediate of said sections from the top of said frame to the bottom thereof supporting said sections and wherein said means to rotate said rotors comprises a motor carried by said vertical member for driving said sections.

5. A unit according to claim 4 wherein said motor has a single internal stator and rotor means surrounding said stator mounted on each said section.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS France Aug. 6, 1910

Claims

1. A FAN UNIT COMPRISING A SHALLOW OPEN VERTICAL FRAME, AT LEAST TWO SIMILAR HOLLOW HORIZONTALLY EXTENDING CYLINDRICAL BLADED ROTORS VERTICALLY ALIGNED WITHIN SAID FRAME AND EXTENDING OVER A MAJOR CROSS-SECTIONAL AREA OF SAID FRAME, MEANS TO ROTATE SAID ROTORS, A FIRST AND A SECOND GUIDE WALL EXTENDING THE LENGTH OF SAID ROTORS POSITIONED ADJACENT EACH SAID ROTOR AND ON OPPOSITE SIDES THEREOF WITH SAID FIRST WALL HAVING A FIRST GUIDE SURFACE EXTENDING IN ONE DIRECTION FROM ONE SIDE OF SAID FRAME SUBSTANTIALLY TOWARD A ROTOR AND A SECOND SURFACE EXTENDING SUBSTANTIALLY AWAY FROM THE ROTOR TO THE OPPOSITE SIDE OF SAID FRAME AND WITH AT LEAST ONE FIRST GUIDE WALL ADJACENT ONE ROTOR JOINING AT BOTH SIDES OF SAID FRAME WITH A SECOND GUIDE WALL OF AN ADJACENT ROTOR; SAID FIRST GUIDE WALL FORMING WITH ITS ADJACENT ROTOR WHEN ROTATED A FLUID VORTEX HAVING A CORE ECCENTRIC OF THE ROTOR AXIS AND INTERPENETRATING THE ROTOR BLADES ADJACENT SAID FIRST GUIDE WALL TO GUIDE AIR ALONG SAID FIRST AND SECOND SURFACES FROM ONE SIDE OF THE FRAME THROUGH THE PATH OF THE ROTATING BLADES INTO THE INTERIOR OF THE ROTOR AND THENCE OUT THROUGH THE PATH OF THE ROTATING BLADES TO THE OTHER SIDE OF THE FRAME WHEREBY AIR IS CAUSED TO FLOW THROUGH A MAJOR PART OF SAID FRAME.