EP0284929A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Mixing apparatus and methods of fabricating same
Assignee: SPX Technologies Inc
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Filing: 1988-03-18
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Granted: —
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Expires: 2008-03-18
Abstract
Abstract A mixer which provides axial flow in a non-uniform flow field, such as may be established by gas which is sparged into a medium being mixed in a tank, and provides large axial flow volume without flooding and withstands variable loads on the blades thereof, thereby providing for reliable operation. The mixer impeller is made up of paddle shaped blades, which near their tips (e.g., at 90% of the radius of the impeller from its axis of rotation) are of a width at least 40% of the impeller's diameter. The blades also having camber and twist. They are formed by establishing bending moments which form the blades into sections which are curved and flat, with the flat sections being at least in the center area of the base of the blades. The hub for attaching the blades to the shaft of the mixer has radially extending arms with flat surfaces. The base of the blades are spaced from the shaft to define areas therebetween. These areas are reduced in size, thereby limiting the passage of sparging gas between the blades and the shaft and the strength of the coupling between the blades and the shaft are enhanced by backing plates of width greater than the width of the arms. These backing plates are fastened between the arms and the flat sections of the blades. Bolts extending through aligned holes in the arms, backing plates and blades provide strong and secure attachment of the impeller blades to the shaft so that the impeller will operate reliably in the environment which provides variable loads on the blade.
Inventors
- 👤 Ronald J. Weetman
- 👤 Richard A. Howk
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 18:03
CPC Classifications
B; B01; B01F; B01F27/00; B01F27/05; B01F27/07; B01F27/071; B01F27/80; B01F27/91; B01F23/00; B01F23/20; B01F23/23; B01F23/233; B01F27/072; B01F27/0726; B01F35/00; B01F35/10; B01F23/2336; B01F23/23362; B01F27/11; B01F27/112; B01F27/1123; B01F27/19; B01F27/191
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
220 words
A mixer including a rotable shaft (18), a hub (40) on said shaft having an arm (42) extending radially from said shaft, and an impeller (20) which provides flow which is predominantly in the direction axially of said shaft in non-uniform flow fields such as the flow field which tends to be influenced by the flow of a gas, characterized in that the impeller (20) has blade means (32,34,36,38), including a blade of paddle shaped planform with a tip end (60), a base end (58) and leading (66) and trailing (68) edges, said blade in the vicinity of 90% of a radius from the axis of the shaft being of width at least 40% of the impeller's diameter, said blade having chamber along a chord between its leading and trailing edges and having a flat section along a surface extending in a region defined by a diagonal between the tip and base ends, said diagonal extending between a point on the tip end closer to the trailing edge than to the midpoint of said tip end between the leading and trailing edges and another point on the base end closer to the leading edge than the midpoint between said leading and trailing edges, and means for attaching said arm to said flat section to mount said blade on said hub.
Claim 2
Dependent Claim
220 words
A mixer including a rotable shaft (18), a hub (40) on said shaft having an arm (42) extending radially from said shaft, and an impeller (20) which provides flow which is predominantly in the direction axially of said shaft in non-uniform flow fields such as the flow field which tends to be influenced by the flow of a gas, characterized in that the impeller (20) has blade means (32,34,36,38), including a blade of paddle shaped planform with a tip end (60), a base end (58) and leading (66) and trailing (68) edges, said blade in the vicinity of 90% of a radius from the axis of the shaft being of width at least 40% of the impeller's diameter, said blade having chamber along a chord between its leading and trailing edges and having a flat section along a surface extending in a region defined by a diagonal between the tip and base ends, said diagonal extending between a point on the tip end closer to the trailing edge than to the midpoint of said tip end between the leading and trailing edges and another point on the base end closer to the leading edge than the midpoint between said leading and trailing edges, and means for attaching said arm to said flat section to mount said blade on said hub.
Claim 3
Dependent Claim
42 words
A mixer according to claim 1, characterized in that a plate (50) having a width greater than the width of said arm extends radially beyond said arm (42), said plate being disposed between said flat surface of said plate and said arm.
Claim 4
Dependent Claim
48 words
A mixer according to claim 2, characterized in that said base end (58) is attached to said arm (42) spaced radially away from said shaft, and in that said plate (50) extends between said base edge and said shaft and occupies at least part of the space therebetween.
Claim 5
Dependent Claim
50 words
A mixer according to claim 3, characterized in that said plate (50) has leading and trailing edges, said leading edge being inclined such that the projections of the plate's leading edge and the blade's leading edge intersect at an obtuse angle in a direction outwardly of said blade and plate.
Claim 6
Dependent Claim
80 words
A mixer according to claim 1, characterized in that a plurality of said blades are provided, each attached at the flat surface thereof to a different one of a plurality of said arms, and in that each said arm has a surface which is flat and is disposed in juxtaposition with said flat section, said arm and said flat section having a plurality of aligned holes therethrough, and bolts in said holes fastening said arm and said blades tightly together.
Claim 7
Dependent Claim
71 words
A mixer according to claim 5, characterized in that a backing plate is disposed between the flat sections of each of said plurality of blades and each of said plurality of arms, said backing plate extending radially outward a distance greater than said arms and being wider than said arms, said backing plates having holes therethrough aligned with said holes in said blades and said arms for receiving said bolts therethrough.
Claim 8
Dependent Claim
69 words
A mixer according to claim 1, characterized in that said leading and trailing edges are approximately parallel to each other, said leading edge is swept back with respect to a radial line extending from the axis of said shaft which intersects said leading edge and said trailing edge is swept forward with respect to a radial line extending from the axis of said shaft which intersects said trailing edge.
Claim 9
Dependent Claim
24 words
A mixer according to claim 5, characterzed in that said blades overlap each other with the leading and trailing edges thereof overlying each other.
Claim 10
Independent Claim
131 words
A method of making an impeller blade from a metal plate, characterized by the steps of locating said plate with respect to tools on opposite sides thereof which tools define a first pair of lines contacting said plate on one side thereof and a second pair of lines having greater separation than said first pair of lines and contacting said plate on the opposite side thereof, bringing said tools toward each other to apply a bending moment to said plate bending said plate beyond its elastic limit to define a section curved along an arc between where said first pair of lines contact said plate, which arc continues into a region of lesser curvature than said arc beyond where said second lines contact said plate to provide camber in said blade.
Claim 11
Independent Claim
131 words
A method of making an impeller blade from a metal plate, characterized by the steps of locating said plate with respect to tools on opposite sides thereof which tools define a first pair of lines contacting said plate on one side thereof and a second pair of lines having greater separation than said first pair of lines and contacting said plate on the opposite side thereof, bringing said tools toward each other to apply a bending moment to said plate bending said plate beyond its elastic limit to define a section curved along an arc between where said first pair of lines contact said plate, which arc continues into a region of lesser curvature than said arc beyond where said second lines contact said plate to provide camber in said blade.
Claim 12
Dependent Claim
30 words
A method according to claim 9, characterized in that said locating step is carried out to locate said lines of contact offset with respect to the center of said blade.
Claim 13
Dependent Claim
110 words
A method according to claim 9, characterized in that said plate is rectangular and has a pair of edges along the width and another pair of edges along the length thereof, and said locating step is carried out by locating said plate with respect to one of said tools providing the first pair of lines so that said first pair of lines intersect one edge of one of said pairs of edges without intersecting the other edge of said one pair of edges, and in that said locating step is carried out by locating said tools with respect to said edges to define angles differing from 90° with said edges.
References Cited (Backward Citations)
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