US1958145A - Fan - Google Patents

Description

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W, A. .sowas y FAN Filed May 25,' 1932 4 Sheets-Sheet l INVENTOR W. A. JONES May 8, l934.

FAN

Filed May 23, 1932 4 sheets-sheet 2 INVENTOR W. A. JQNES FAN Filed May 25. l932 4 Sheets-Sheet 3 Wj. FAN

Filed; May 23, 1952 i Sheets-Sheet 4 Patented May 8, 1934 UNITED STATES FAN William Anthony Jones,

West New Brighton, N. Y.

Application May 23, 1932, Serial No. 612,952

15 Claims.

My invention relates particularly to fans which receive gas at one side and discharge it at the other side and is a modification of that describedin United States Patent #1,447,554 issued to me March 6, 1923.

This modification consists in making the angularity of the stationary blades and of the moving blades each diierent for different distances from the center of the shaft so that for a definite volume of gas and speed of fan, the resulting velocity of the gas will be the same for all distances from the center of the shaft, with resulting reduction in eddies and in friction loss.

This result may be obtained without much thrust on the vfan wheel bearings by making the wheel blades with a retreating angle at their outer radius and an advancing angle at their inner radius, so that the resulting axial thrusts on the anwheel about neutralize each other. Nearly 20 all of the thrust is on the stationary blades.

Having in mind that the energy of motion and the pressure against which the motion will drive a gas is asthe square of the velocity, the desirability of having the samevelocity atvall radii is evident. If the velocity were directly as the radii so that the velocity at the outer radius was, for instance, six units while the velocity at the inner radius was ve units, then the squares of these quantities would be as thirty-six is to twenty-five, which would be the relation of the pressure at the outer radius compared to that at the inner radius.

Referring to the accompanying drawings; Fig. l is a longitudinal section of a two-stage fan with stationary blades and with chords of curved moving blades each having dilerent angularities which compensate for the dilerent speeds of the inner and the ou'ter radii of the fan wheel.

Fig. 2 is a part end view of the fan shown in o Fig. l.

Fig. 3 is a part development of the side View of this fan, showing shape of blades and openings for discharge of dust accompanied by some gas.

Fig. 4 and Fig. 5 are enlarged views of moving blades showing difference in angularity of chords at inner and `at outer radii.

Fig. 6 is a longitudinal section of an eight-stage fan with surfaces of moving blades formed of straight lines corresponding to the chords of the moving blades shown in Fig. 1 and otherwise identical with Fig. 1.

` Fig. 7 isa part development showing a side View of the blades when the casing is removed to indicate the shape of th; blades, for'the fan shown in Fig. 6, being similar to Fig. 3 which is such a development for the fan shown in Fig. 1.

Fig. 8 is an enlarged view of stationary and moving blades of eight-stage fan, showing difference in angularity of lines at inside radius and at outside radius, similar to Fig. 4.

v Fig. 9 is an enlarged part sectional view through the forward and rear edges of the fan wheel and stationary cones showing the edges beveled.

Fig. 10 is a diagram showing lines representing velocities of gas in its passage through the fan.

Figure 11 is a diagram showing lines representing velocities of gas in its passage through a fan, with a single row of moving blades, the fan being otherwise like that shown in Figs. 6, 7 and 8, with blades formed of straight lines.

Figure 12 is a diagram-showing the manner of applying the method of development disclosed in Fig. l1, to the multiple stage fan shown in Figs. 6, 7 and 8.

Similar parts are referred to by similar numerals throughout the several views.

Referring to the drawings:

A fa wheel, 1; provided with blades, 2, is mounted on a shaft, 3;' Shaft, 3, is driven from shaft, 4, through gears, 5, and 6.

The fan casing is represented as having an inlet part, 7,-an outlet part, 8, and a central part, 9, the latter made of pieces joined by flanges, 10, so that the parts can-be conveniently removed.

A conical shield, 11, concentric with the inlet part, 7, shields the central part of the fan wheel, 1. A similar shield, 12, shields the central part of the wheel in the outlet part. 8.

The space, 13, between the conical shield, 11, and the inlet part, 7, of the casing, forms a passage of gradually decreasing area for gas as it approaches the fan wheel blades, 2. Stationary guide `vanes, 14, in the space, 13, between the conical shield, 11, andthe casing, 7, determine the direction of flow of gas to the wheel, 1.

These guide blades, 14, are more obliqueto the axis near the wheel, at the outside radius at, l5, than at the inside radius, at 16. 'Similar stationary guide vanes, 17, in the space, 18, between the conical shield, 12, and the casing, 9, determine the direction of ow of gas as it leaves the blades of the wheel. These guide blades are also more oblique to the axis nearthe wheel at the outside radius, at 19, than at the inside radius, at 20.

Inclination of the stationary Varies, 14, and, 17. with respect to the axis causes an axial thrust ou the gas Without a corresponding axial thrust oi: the fan wheel.

that the wheel in effect overlaps the cones, tending to add to the pressure on the inlet side of the wheel and to decrease the pressure on the outlet side of the wheel. Wheel disks are provided with openings, 23, all to avoid difference in pressure on the two sides of the wheel.' I f Beyond the Wheel a cylindrical baffle plate, 24, is joined to the shell, 8, at, 25, and presents an opening at 26 for ow of dust-laden gas to openings 27 which discharge into a girth channel, 28, terminating in an outlet, 29. i

Referring to the diagram, Fig. 10, line 30-31 being proportional to the inner radius, line 30-3'7 being proportional to the outer radius, then line 30-32, and line 30--38 represent the direction and velocity of flow of gas approaching the fan as determined by the inclinations of the stationary blade at the inside radius and at the outside r'adius, and at an assumed volume equal to five-y eighths of thefree-ilow volume of gas.

Lines 3l-32, and lines 3'7--38 represent velocities, relative tothe fan`wheel, at the inside and at the outside, of gas. as it approaches the wheel.

Lines 32-33, and 38--39 represent velocities of gas, relativeto the fan wheel, as it leaves the wheel.

the velocities at the inside and at the outside which would obtain but for friction and but for the outlet pressure being greater than the inlet pressure.

The squares ofthe lengths of these lines cornpared to the squares of the lengths of .lines 13D-32,.-

and 30-38 is proportional to the increase in pressure and friction loss.,

The stationary vanes, 14, at the inlet side of the fan and, 1'?, at the outlet side of the "fan, determine the direction of gas flow as it approaches and as it leaves the fan.

Vanes, 17, are subject to a slight impact of gas,

due to angles somewhat less than those between lines connecting points 35-324-36, 'and points 41-38-42. Other blades are without impact under the assumed conditions, except at their edges.

' Absence of impactconduces to efiiciency.

vThe constructionshown gives a relatively long axial travel for dust and gas and a relativelyv long time for the separation of the extremely small flocculent ash resulting from burning powdered coal. This is particularly thefcase for the mult'iplef-stage fanwhich also results in greater pressure for a givenspeed.

Y As is known, the elastic air particles bounce from a'surface against which they impinge at an angle equal to that with whichthey strike the surfaceybvhereas particles of inelastic water slide from the surface and do not bounce from the surface. Accordingly, it will be readily understood that whereas for.` a propeller to act inwater the Y pitch should be constant for all radii, this is not the case for a propeller to act in air. s

For theV apparatus described in this invention, making the sinevof the angle between the stationary vanes and the axis directly proportional to the radius as shown, results in equal entering velocity at all radii, for a given percentage of the free flow volume, as diagram, Fig. 10, shows. The pitch increases towards the center.

In Fig. 11, I have shown how the inner and the outer lines of the stationary vanes and of the moving vanes of the fan are determined to give line 32-l34, representing gas velocity at the inner edge equal to line 38--140, representing gas velocity at the outer edge of the blade. Curved blades, 186, without batting or bouncing action, could be used instead of straight blades 2.

Figure 12 shows in heavy straight lines the shape of the inner edge of stationary and of moving blades using bouncing action and in light dotted curved lines shows the possible shape of the inner edges of the blades without bouncing action but arranged so that the gas slides onto and off of the blades with'out impact.

With the above in mind it is easy to understand why ordinary fans sometimeshave an efficiencyl results iny about the same change in velocity and direction of ow with straight fan blades, like one of those shown in`Figs. 6, '7 and8, as for the curved blade, asshown in Figs. 1, 2 and 3, where/impact is avoided for a given percentage of free iiow volume. The curved blade also avoids interfering withthe ow from adjacent blades.

A spray of water or nonvolatile liquid, 50, discharged into theincoming gas from pipe, 51, may

be used to give weight to extremely light dust and assist its' separation. The spray of water may also be used periodically to wash the inside surfaces of the apparatus.

,Oil pipes, 52, 53, 54 and 55, convey oil for lubricating and cooling the bearings.

I claim: 1. Inapparatus for causing gas to ow from a lower pressure to a higher pressure, the combination' of a fan Wheel with blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet sideof the fan Wheel, stationary vanes between the` conical shields and the casing, the stationary vanes near the wheel being more oblique to the axis at their outer radius than at their inner radius, so that the sine of the angle of inclination measured on a plane perpendicular to the radius is directly proportional to the radius. 2. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a fan wheel with blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the fan wheel, oblique stationary vanes between the conical shields and the casing, the stationary vanes near the wheel being more oblique to the axis(at their outer radius than at their inner radius, so that the sine of the angle of the inclination is directly proportional to the radius,

the blades of the wheel being made so that lines i 3. In apparatus for causing gas to flow from a"A lower pressure to a higher pressure, the combination of a fan wheel with blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the fan wheel, oblique stationary vanes between the conical shields andthe casing, the

stationary vanes near the wheel being more oblique to the axis at their outerradius than at their inner radius, so that the sine of the angle of the inclination is directly proportional to the radius, the blades ofthe wheel being made so that lines connecting their forward and rear edges are at different angles measured on a plane perpendicular to the radius for the inner radius and the outer radius.

4. In apparatus for causing gas to ow from a lower pressure to a higher pressure, the combination of a fan wheel with blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the fan wheel, stationary vanes between the conical shields and the casing, the stationary vanes near the wheel being more oblique to the axis at their outer radius than at their inner radius, so that the sine of the angle of the inclination is directly proportional to the radius, the blades of the wheel being made so that lines connecting their forward and rear edges are at different angles referred to a transverse plane for the inner radius and the outer radius, and the blades of the wheel are made curved so that for a given speed of fan and volume of gas the curve of the blade will be tangent to the path of the entering gas rrelative to the blade at the inside radius and at the outside radius, as shown.

5. In apparatus for causing gas to flow from a lower pressure -to a higher pressure, the combination of a fan wheel with blades, a casing having a concentric conical shield at the inlet sideof the fan wheel, a second conical shield at the outlet side of the fan wheel, stationary vanes between the conical shields and the casing, the stationary vanes near the wheel being more oblique to the axis at their outer radius thant at their inner radius, so that the sine of the angle of the inclination is directly proportional to the radius,

the blades of the wheel being made so that linesl connecting-'their forward and rear edges are atv dierent angles referred to a transverse, plane for the inner radius and the outer radius, and the blades of the wheel are made curvedso that for a given speed of fan and volume of gas the curve of the blade will be tangent to the path of the entering gas-relative to the `blade at the inside radius and at-the outside radius, and the action of the blade imparts about the same velocity to the gas at the inner radius and at the outer radius.

. 6. In apparatus for causing gas to ow from a lower pressure'fto a higher pressure, thev come,

bination of a fan wheel with more than one row of blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the fan wheel. and oblique stationary blades between the conical shields and the casing and between therows of blades of the wheel, the stationary vanes being more oblique to the axis at their outer radius than at their inner radius, so thatlthe sine ofthe Yangle of their inclination measured on a plane perpendicular to the,l radius is directly proportional to the radius.

7. In apparatus for causing gas to ow from a lower pressure to a higher pressure, the com-,7,

Ioblique stationary blades between the conical shields andthe casing and between the rows of blades of the wheel, the stationary vanes near the wheel being more oblique to the axis at their outerradius lthan at their inner radius, so that the sine of the angle of the inclination is` directly, proportional to the radius, the blades of each. row of the wheel, being made so` that lines connecting their forward and rear edges are at an advancing angle for the inner radius tothereby cause the gas to move circumferentially faster than theA wheel and at a retreating angle for the outer radius.

8. I n apparatus for causing gas to owvfrom a lower pressure to a higher pressure, the combination of a fan wheel with more than one row of blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet'side of the fan wheel, and oblique stationary blades between the conical shields and the casing and between the rows of blades ofthe wheel, the stationary vanes near the Wheel being more oblique to the axis at their outer radius than at their inner-radius, so that the sine of the angle of the inclination is directly proportional to the radius, the blades of each row of the wheel, being made so that lines connecting their forward and rear edges; are at different angles measured on a plane perpendicular to the radius for the inner radius and the outer radius.

9. In apparatus forycausing gas to flow .from a lower pressure to a higher pressure, the combination of a fan wheel withblades, a casing having `a,concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the fan wheel, stationary vanes,

between the conical shields and the casing, the stationary vanes near the wheel being more oblique to the axis 'at their outer radius than at their inner radius, so that the sine of the angle of inclination measured on a plane perpendicular to the radius is directly proportional tothe radius, an inlet for gas at one side of the fan wheel, an outlet for gas at the other side of the fan wheel, and a second outlet for` dust at a greater distance from the center than the first outlet.

10. In apparatus for causing gas to flow from a lower pressure toAa higher pressure, the combination of a fan wheel with blades, a. casing having a concentric conical shield. at the .inlet side of the fan wheel, a second conical shield ait the radius, the blades of the wheel being made so, that lines connecting their forward and rear' edges are at an advancingangle so that the gas moves circumferentially faster thanthe wheel for the inner radius and at a retreating angle for the outer radius, an inlet for gas at one side of the fan wheel, an outlet for gas at the ,other side of the fan wheel, a second outlet for dust at a greater distance from first outlet. t

11. In apparatus for causing gas to flow from aflower pressure to a higher pressure, the combination of a fan wheel with blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the fan wheel, 'and oblique stationary vanesbetween the conical shieldsand the casing, the stationary vanes near the Wheel being more oblique to the axis at their outer radius than at their inner radius, so that the sine of the angle of the inclination is directly prothecenter than the portional to the radius, the blades of the wheel being made so that lines connecting their forward andrear edges are at diierent angles measured on a plane perpendicular to the radius for the inner radius and the outer radius, an inlet for gas at one side of the fan wheel, an outlet for gas at the other side of the fan wheel, a second outlet for dust at a Agreater distance from the center than the rst outlet. 4

- l2. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a fan wheel with more lthan one row of blades, acasing having a concentric conical shield at the inlet side of the fan Wheel, a second conical shield at the outlet side of the fan wheel, and oblique stationary vanes between the conicalshields and the casing and between the rows of blades of the wheel, the stationary vanes near the wheel being more oblique to the axis at their outer radius thanat their inner radius, so that the sine of the angle of the inclination is directly proportional to the radius, the blades of the wheel being made so that lines connecting their forward and rear edges are at different angles measured on a plane perpendicular to the radius for the inner radius and the outer radius, an inlet for gas vat one side of the fan wheel, an outletior gas at the other side of the fan wheel, a second outlet ,for dust at a greater distance from the center than the first outlet. i

13. In apparatus for causing,V gas to flow from a lower pressure to a higher pressure, the combination of a fan wheel with more than one row of blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the fan wheel, and stationary vanes between the conical shields and the -casing and between the rows of blades of the wheel, the stationary vanes near the wheel being more oblique to the axis at their outer radius than at their inner radius, so that the sine of the angle of the inclination is directly proportional to the radius, the blades of the wheel being made so that lines connecting their forward and rear edges, for each row, are at different angles measured on a plane perpendicular to the radius for theinner radius and the outer radius,

and the blades of the Wheel are curved so that for a given speed of'fan and volume of gas the curve of the'blade will be tangent to the path of the entering gas relative to that blade, at the inside radius and at the outside radius.

14. In apparatus for causing gas to ow from a 'lower pressure to a higher pressure, the cornbination of a fan wheel with more than one row of blades, a casing having a concentric conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side ofthe fan wheel, stationary vanes between the conical shields and the casing and between the rows of blades of the wheel, the stationary vanes near the wheel being more oblique to the axis at their outer. radius l than at their inner radius, so that the sine of the angle of the inclination is directly proportional to the radius, the blades of the wheel being made so that lines connecting their forward and rear edges, for each row, are at different angles measured on a plane perpendicular to the radius for the inner radius and the outer radius, and the blades of the wheel are curved so that for a given speed of fan and volume of gas the curve oi' the blade will be tangent to the path of the entering gas relative to the blade, at the inside "radiusand at the outside radius, an inlet forgas at one side of the fan wheel, an outlet for gas at the other side of the fan wheel, and a second outlet for dust at a greater distance from the center than the first outlet. g

V15. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a fan wheel with blades, a casing having a concentriciconical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the fan wheel, and stationary vanes .between the conical shields and the casing, the stationary vanes near the wheel. being more oblique to the axis at their outer radius than at. their inner radius, so that the sine of the angle of v WILLIAM ANTHONY JONES.

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