US3794439A

US3794439A - Radial blower

Info

Publication number: US3794439A
Application number: US00310473A
Authority: US
Inventors: D Haase
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-12-03
Filing date: 1972-11-29
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26
Also published as: DE2160047B2; DE2160047A1; FR2164216A5; DE2160047C3

Abstract

A radial blower has an impeller with a radially vaned rim rotatably mounted in a housing adjacent a discharge conduit. The portions of the housing on both sides of the discharge conduit incline outwardly away from the impeller to form wedge-shaped inlet and discharge chambers on both sides of the impeller. The larger ends of the suction and discharge chambers are joined by a return or bypass channel which directs the main portion of flow away from the back into the impeller. The portion of the impeller between the suction and discharge chambers is bordered by a concavely curved flow diverting element having a radius of curvature slightly smaller than the impeller and a maximum distance at its mid-section, which is substantially equal to the radial length of the vanes on the rim of the impeller. An inlet or suction opening in the front wall of the housing is eccentrically disposed relative to the impeller and adjacent the inlet chamber. The inlet conduit is inclined toward the suction chamber. A set of curved deflectors is disposed substantially parallel to each other in the central chamber of the housing within the impeller vanes and substantially in line with the discharge chamber and conduit and having tip ends fairly close to the inner ends of the impeller vanes of the discharge conduit.

Description

United States Patent 1191 Haase RADIAL BLOWER Dietrich E. Haase, 544 Mayen, Habsburgring 90, Germany 221 Filed: Nov. 29, 1972 211 Appl. No.: 310,473

[76] Inventor:

[30] Foreign Application Priority Data Primary ExaminerC. J. Husar Attorney, Agent, or Firm-Connolly & Hutz [451 Feb. 26, 1974 [57] ABSTRACT A radial blower has an impeller with a radially vaned rim rotatably mounted in a housing adjacent a discharge conduit. The portions of the housing on both sides of the discharge conduit incline outwardly away from the impeller to form wedge-shaped inlet and discharge chambers on both sides of the impeller. The larger ends of the suction and discharge chambers are joined by a return or bypass channel which directs the main portion of flow away from the back into the impeller. The portion of the impeller between the suction and discharge chambers is bordered by a concavely curved flow diverting element having a radius of curvature slightly smaller than the impeller and a maximum distance at its mid-section, which is substantially equal to the radial length of the vanes on the rim of the impeller. An inlet or suction opening in the front wall of the housing is eccentrically disposed relative to the impeller and adjacent the inlet chamber. The inlet conduit is inclined toward the suction chamber. A set of curved deflectors is disposed substantially parallel to each other in the central chamber of the housing within the impeller vanes and substantially in line with the discharge chamber and conduit and having tip ends fairly close to the inner ends of the impeller vanes of the discharge conduit.

12 Claims, 2 Drawing Figures PATENYED EBZB I974 FIG.2

RADIAL BLOWER BACKGROUND OF THE INVENTION This invention relates to a radial blower wherein the gaseous fluid being pumped is conducted in a multiplicity of passes through a radially vaned impeller.

It is known in the art that relatively high pressures may be produced in radial blowers by utilizing high peripheral speeds (B. Eck, Ventilatoren (Ventilators), 3rd Ed., Berlin 1957, p. 7, equation 11). It is also known in the art that a pair of radial impellers may be mounted on a common shaft and successively utilized to increase the pressure one after the other. In a relatively new type of radial blower described in published West German patent application DTOS 1,808,829, the gaseous fluid is circulated in a normal manner about one-half of the circumference of a radial impeller into an outwardly deviating spiral housing which returns to the proximity of the impeller in the other half of the circumference of the impeller, whereby the fluid is recirculated through the impeller blades to increase its pressure.

The peripheral speed of a radial impeller is limited by the physical strength of its structural material or by the tolerable sound level. A pair of radial impellers connected in series with careful construction and arrangement may provide relatively high pressures at a fairly high degree of efficiency, but require considerable extra parts and increased expense. Recirculation of the fluid through a single radial impeller by an arrangement (such as described in published DTOS 1,808,829 having the chamber surrounding the impeller divided into three sections, and particularly by an outwardly opening spiral, an inwardly closing spiral, and a discharge conduit) makes it possible to obtain a considerable increase in pressure with a relatively low cost of construction, but it does not make it possible to simultaneously favorably influence the pressure and degree of efficiency.

An object of this invention is to control the recirculation of a gaseous fluid through a radial impeller of a blower in such a manner that the pressure and degree of efficiency are significantly increased with'a relatively small increase in the cost of construction in comparison to that previously described.

SUMMARY OF THE INVENTION In accordance with this invention, the aforementioned object is obtained by bordering the radial impeller on the side opposite the discharge conduit by a concavely curved flow diverting element having its concave wall disposed toward the radial impeller and having a radius of curvature slightly smaller than that of the impeller and a maximum'spacing at its mid-section from the impeller substantially equal to the length of the vanes on the impeller. In other words the flowdiverting elements divert flow inwardly between the vanes of the impeller.

This divides the housing about the circumference of the impeller into four sections, which taken in direction of impeller rotation, include a discharge conduit, a wedge-shaped (or outwardly deviating) inlet chamber substituted for the aforementioned outwardly opening spiral, a concavo-convex flow diverting baffle disposed opposite the discharge conduit, and a wedge-shaped (or inwardly deviating) discharge chamber substituted for the inwardly developing spiral. The larger ends of the inlet and discharge chambers are connected by a return or bypass channel whose configuration determines the desired amount of increase in pressure to be obtained from the blower.

This invention has the advantage of at a relatively small structural expense with a single radial impeller having a relatively small throughput providing higher pressures which otherwise would require two successive radial impeller stages. Another particularly helpful advantage is in that the speed of rotation is decreased, which minimizes the strength of the required construction materials, which is important for example when synthetics or plastics are utilized. The relatively low peripheral speeds also helpfully reduces the sound levels.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2 is shown a radial blower having a radial impeller 1 with an annular array of radial vanes 15 rotatably mounted between flat front housing wall 2 and rear housing wall 3. Impeller vanes 15 are slightly curved and swept outwardly forward in the direction of rotation. The portion of the housing disposed between impeller vanes 15 is designated for convenience as a central chamber. The portion of vaned rim 16 of impeller l disposed adjacent suction opening 5 in front wall 2 is bordered by inlet chamber 6 which deviates gradually outwardly away from impeller l in the direction of rotation away from discharge conduit 10 into a wedge shape. Inlet chamber 6 is connected by return or bypass channel 9 with inwardly deviating or wedge-shaped chamber 8 disposed on the opposite side of discharge conduit 10 from inlet chamber 6. The opposite side of impeller 1 from discharge conduit 10 is bordered by the concavely curved side of concave-convex flow diverting baffle 7 having a concave radius of curvature substantially equal to the average radius of curvature of vaned rim 16. The maximum spacing between the midsection of concave wall of element 7 is substantially equal to the radial length of vanes 15 on vaned rim 16. An array of substantially parallel

curved deflector vanes

11, 12 and 13 is mounted in the central chamber adjacent discharge conduit 10 and has tip ends disposed near the inner ends of the impeller vanes 15. The

vanes

11, 12 and 13 are attached to the front wall 2 and project inwardly therefrom. Deflector vanes 1 1, 12 and 13 are disposed substantially parallel to the average line of flow through discharge chamber 8 and discharge conduit 10 and extend substantially adjacent the inner periphery of vaned rim l6. Curved deflector vane 11, having the largest radius of curvature and length, is

thus disposed substantially tangent to an angle bisecting the portion of impeller 1 bordered by exhaust conduit l0.

Suction conduit 4, connected in series with suction opening 5, is inclined with respect to the axis of rotation of impeller l and toward the area of impeller l bordered by inlet chamber 6. Suction conduit 4 also may have attached to its outer end (in a manner not shown) an inlet elbow conduit having an end remote from illustrated conduit 4, whose axis is disposed substantially parallel to the axis of rotation of impeller l.

A radial blower of this invention as described herein has achieved an output of over 50 percent, a pressure number (of performance) of 2.4 and yield numbers (of performance) of less than 0.1 referring to the circular surfaces of radial impeller 1. These definitions are described and discussed in a publication entitled Ventilatoren (Ventilators) by B. Eck, published in Berlin, Germany, in 1967.

The principal portion of the fluid passing through the radial blower of this invention passes from suction conduit 4 into the central portion of radial impeller 1 and from there into inlet chamber 6. This principal portion is then subsequently passed through return or bypass channel 9 into inwardly deviating discharge chamber 8 and then after again passing through impeller 1 flows into discharge conduit 10. Some of the impelled gaseous fluid passes from suction conduit 4 into the concave chamber bordered by flow diverting element 7 in which a return flow occurs toward the central chamber disposed within the radial impeller. The portion of the gaseous fluid from which this reversal of flow occurs if split by nozzle suction 14 which is disposed closely adjacent impeller 1 at the beginning of inlet chamber 6 in such a manner that one portion flows directly into discharge conduit 10 and the other flows into the narrow entrance to inlet chamber 6. This reduces the speed of flow in the portion of discharge conduit 10 adjacent nozzle 14 relative to the average speed of flow through discharge conduit 10, which materially reduces the noise produced by the blower. On the other hand, the speed of flow in inlet chamber 6 otherwise increases which reduces flow losses in channel 9.

The structure of the radial blower is highly simplified by constructing it within a casing having an over-all elliptical cross-section with impeller 1 and discharge conduit 10 at one end and return or bypass channel 9 at the other end. Bypass or return channel 9 is constituted by arcuately pointed concavo-convex baffle 7 whose concavely curved side borders the periphery of impeller 1 which is disposed opposite discharge conduit 10. The convexly curved side of baffle 7 forms the inner wall of return channel 9.

I claim:

1. A radial blower comprising a housing having a curved periphery, an impeller having a radially vaned rim, shaft and bearing means rotatably mounting said impeller within said housing, said housing also having a front wall disposed adjacent a vaned side of said impeller, a suction opening in said front wall eccentrically disposed relative to said impeller, a discharge conduit in the portion of said periphery near said suction opening, the portion of said peripheryin the direction of rotation of said impeller away from said discharge conduit deviating outwardly from a nozzle section disposed substantially adjacent to said impeller at said discharge conduit into a wedge-shaped inlet pressure chamber of increasing cross-sectional area, the portion of said periphery on the side of said discharge conduit opposite to said nozzle approaching inwardly toward said impel ler in the direction of rotation of said impeller to form a wedge-shaped discharge chamber, a curved return channel connecting the wider ends of said inlet and discharge chambers for conducting the main portion of pumped fluid from said inlet chamber to said discharge chamber whereby it is directed back into said impeller, the portion of said impeller disposed opposite said discharge conduit and between said suction and discharge chambers having a concavely curved bordering element disposed adjacent said impeller and bridging the portion of said impeller disposed between said inlet and discharge chambers and said return channel, and said concavely curved bordering element having a curvature constructed and arranged to divert flow between it and said impeller inwardly between said vanes of said impeller.

2. A radial blower as set forth in claim 1 wherein said concavely curved bordering element has a radius of curvature slightly smaller than the radius of curvature of said impeller.

3. A radial blower as set forth in claim 2 wherein said concavely curved bordering element has a midsectional maximum spacing from said impeller substantially similar to the radial length of said vanes.

4. A radial blower as set forth in claim 1 wherein the.

portion of said housing within said vanes comprises a central chamber, deflector vanes projecting from said front wall and being. disposed in said central chamber substantially parallel to the line of flow through said discharge chamber and said discharge conduit whereby fluid currents circulating within said central chamber are directed into said discharge conduit.

5. A radial blower as set forth in claim 1 wherein said impeller vanes and said deflector vanes have portions adjacent said discharge conduit disposed near to each other.

6. A radial blower as set forth in claim 4 wherein said deflector vanes are slightly curved.

7. A radial blower as set forth in claim 6 wherein said deflector vanes are disposed substantially parallel to each other and have substantially similar radii of curvature.

8. A radial blower as set forth in claim 1 wherein a suction conduit is connected to said suction opening on said front wall of said housing and said suction conduit being inclined toward said inlet chamber whereby it directs suction fluid into said inlet chamber.

9. A radial blower as set forth in claim 8 wherein a curved elbow section is connected to said inclined suction conduit, and said curved elbow section has a portion remote from said inclined section which is disposed substantially parallel to the axis of rotation of said impeller.

10. A radial blower as set forth in claim 1 wherein said housing comprises a substantially elliptical outer casing, said impeller being disposed at one end of said elliptical casing, said return channel being disposed at the other end of said elliptical outer casing, and said concavely curved bordering wall and the'inside wall of said return conduit comprising a concavoconvex baffle disposed within said casing with its concave wall facing said impeller.

11. A radial blower as set forth in claim 1 wherein said vanes are slightly curved.

12. A radial blower as set forth in claim 11 wherein said vanes slightly curve outwardly forward.

Claims

1. A radial blower comprising a housing having a curved periphery, an impeller having a radially vaned rim, shaft and bearing means rotatably mounting said impeller within said housing, said housing also having a front wall disposed adjacent a vaned side of said impeller, a suction opening in said front wall eccentrically disposed relative to said impeller, a discharge conduit in the portion of said periphery near said suction opening, the portion of said periphery in the direction of rotation of said impeller away from said discharge conduit deviating outwardly from a nozzle section disposed substantially adjacent to said impeller at said discharge conduit into a wedgeshaped inlet pressure chamber of increasing cross-sectional area, the portion of said periphery on the side of said discharge conduit opposite to said nozzle approaching inwardly Toward said impeller in the direction of rotation of said impeller to form a wedge-shaped discharge chamber, a curved return channel connecting the wider ends of said inlet and discharge chambers for conducting the main portion of pumped fluid from said inlet chamber to said discharge chamber whereby it is directed back into said impeller, the portion of said impeller disposed opposite said discharge conduit and between said suction and discharge chambers having a concavely curved bordering element disposed adjacent said impeller and bridging the portion of said impeller disposed between said inlet and discharge chambers and said return channel, and said concavely curved bordering element having a curvature constructed and arranged to divert flow between it and said impeller inwardly between said vanes of said impeller.

3. A radial blower as set forth in claim 2 wherein said concavely curved bordering element has a mid-sectional maximum spacing from said impeller substantially similar to the radial length of said vanes.

4. A radial blower as set forth in claim 1 wherein the portion of said housing within said vanes comprises a central chamber, deflector vanes projecting from said front wall and being disposed in said central chamber substantially parallel to the line of flow through said discharge chamber and said discharge conduit whereby fluid currents circulating within said central chamber are directed into said discharge conduit.

10. A radial blower as set forth in claim 1 wherein said housing comprises a substantially elliptical outer casing, said impeller being disposed at one end of said elliptical casing, said return channel being disposed at the other end of said elliptical outer casing, and said concavely curved bordering wall and the inside wall of said return conduit comprising a concavoconvex baffle disposed within said casing with its concave wall facing said impeller.