Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/60—Mounting; Assembling; Disassembling
  • F04D29/64—Mounting; Assembling; Disassembling of axial pumps
  • F04D29/644—Mounting; Assembling; Disassembling of axial pumps especially adapted for elastic fluid pumps
  • F04D29/646—Mounting or removal of fans
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/08—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/08—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation
  • F04D25/10—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation the unit having provisions for automatically changing direction of output air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/08—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation
  • F04D25/12—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation the unit being adapted for mounting in apertures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/40—Casings; Connections of working fluid
  • F04D29/52—Casings; Connections of working fluid for axial pumps
  • F04D29/54—Fluid-guiding means, e.g. diffusers
  • F04D29/541—Specially adapted for elastic fluid pumps
  • F04D29/542—Bladed diffusers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/40—Casings; Connections of working fluid
  • F04D29/52—Casings; Connections of working fluid for axial pumps
  • F04D29/54—Fluid-guiding means, e.g. diffusers
  • F04D29/541—Specially adapted for elastic fluid pumps
  • F04D29/542—Bladed diffusers
  • F04D29/544—Blade shapes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/40—Casings; Connections of working fluid
  • F04D29/52—Casings; Connections of working fluid for axial pumps
  • F04D29/54—Fluid-guiding means, e.g. diffusers
  • F04D29/56—Fluid-guiding means, e.g. diffusers adjustable
  • F04D29/563—Fluid-guiding means, e.g. diffusers adjustable specially adapted for elastic fluid pumps

Definitions

• This invention relates generally to an axial fan and, more particularly, to an improved mounting arrangement for mounting the motor of an axial fan within an outer case.
• an axial fan typically comprises an outer cylindrical case 10 within which a motor 12 is mounted, with pressed or fabricated steel brackets 14 being used to connect and hold the motor within the case 10.
• An impeller 16 is also provided within the case 10, which comprises a plurality of blades 18 extending from a central hub, and which is connected to the shaft of the motor for propulsion thereby.
• a support arm for a mounting arrangement for mounting a motor of an axial fan within an outer casing, the support arm comprising an elongate vane arranged and configured to extend between said motor and the inner wall of said casing, and a connecting portion for connecting said vane to said motor, said connecting portion comprising means for varying the angle of the surface of said vane relative to the direction of airflow through said axial fan.
• the support arm vane is designed to be fixed to the motor and not varied in angular position during service. The angle is pre-selected as a specific service angle and fixed in place.
• the invention enables specific angled arm vane to be used in variable angular orientations dependent upon the "in service” requirements and the specific fan structure and size. Accordingly, it is preferred that the vane is secured with respect to the motor at a specific "in service” angular orientation and not subsequently varied. Beneficially the vane is secured to the motor by means of a tightening mechanical fixing such that the orientation of the vane cannot be varied (once fixed) without releasing the mechanical fixing by untightening.
• said connecting portion comprises an arcuate slot defining a plurality of selectable angular orientations at which said elongate vane can be mounted.
• the arcuate slot is provided on a connecting plate which is substantially perpendicular to, and formed integrally with, said elongate vane.
• the arcuate slot is beneficially arranged and configured to receive a connector such that it extends through said slot into a mounting hole provided on said motor.
• the angle of the surface of the vane measured between a first axis perpendicular to the longitudinal axis of said elongate vane and a second axis parallel to the longitudinal axis of said axial fan, is between 80° and 50°, and more preferably between 70° and 55°. In one preferred embodiment, the angle is between 65° and 60°.
• the angle of the profile of the elongate vane varies along its length.
• the elongate vane might be twisted through, say, 15° along its length.
• the vane could be bent by, say, 15° at, say, 3/3 of its full length.
• a support arm for a mounting arrangement for mounting a motor of an axial fan within an outer casing, the support arm comprising an elongate vane arranged and configured to extend between said motor and the inner wall of said casing, and a connecting portion for connecting said vane to said motor, wherein the angle of the profile of the elongate vane varies along its length.
• the elongate vane might be twisted through, say, 15° along its length.
• the vane could be bent by, say, 15° at, say, 3/3 of its full length.
• the present invention extends to an axial fan comprising a motor and an impeller housed within an outer casing, the fan further comprising a mounting assembly for mounting said motor within said casing, the mounting assembly comprising one or more support arms as defined above connected between said motor and the inner wall of said outer casing.
• the support arms are connected between the motor and the inner walls of said outer casing by means of a connector assembly comprising means for connecting said vane to said motor at a selected one of a plurality of longitudinal distances from said impeller.
• the motor may be provided with a plurality of discrete, beneficially substantially equi-distant, mounting holes defining the respective distances.
• an axial fan comprising a motor and an impeller housed within an outer casing, the fan further comprising a mounting assembly for mounting said motor within said casing, said mounting assembly comprising at least one elongate vane extending between the inner wall of said casing and said motor and being connected to said motor by means of a connector assembly comprising means for connecting said vane to said motor at a selected one of a plurality of distances from said impeller.
• brackets that are manufactured in an aerofoil section and are twisted along their length, a significant improvement in aerodynamic performance (i.e. movement of larger volumes of air at higher pressure) can be achieved. Further improvement can be achieved by making the brackets adjustable, such that the distance thereof from the impeller can be varied and the angle thereof can be matched to the direction of airflow, depending on the type of impeller being used.
• Figure 1 is a perspective view of an axial fan according to the prior art
• Figure 2 is a perspective view of an axial fan including a mounting arrangement according to an exemplary embodiment of the present invention
• Figure 3 is a perspective view of a mounting arm of a mounting arrangement according to a first exemplary embodiment of the present invention
• Figure 4 is a perspective view of a mounting arm of a mounting arrangement according to a second exemplary embodiment of the present invention.
• Figure 5 is a close-up view of a motor-connecting portion of one of the mounting arms of the mounting arrangement of Figure 2;
• Figure 6 is a schematic illustration showing the support arm at various angles relative to the airflow direction
• Figures 7 and 8 are illustrative of the relationship of velocities of an axial fan blade at two respective points
• Figures 9, 10, 11 and 12 are illustrative of airflow as a result of angling the support arms at 90°, the ideal position, under-rotation of the support arms, and over-rotation of the support arms, respectively;
• Figure 13 illustrates the force applied to an impeller blade during use
• an axial fan according to an exemplary embodiment of the present invention comprises a cylindrical outer case 30 having a circumferential flange 32 at each end thereof, each flange extending upwardly relative to the outer wall of the case 30 and substantially perpendicular thereto.
• the fan further comprises an impeller 34 consisting of a plurality of blades 36 extending from a central hub.
• the impeller 34 is housed within the case 30 and connected to the shaft of a motor 38 for propulsion thereby.
• the motor 38 is mounted within the case 30 by four substantially equi-distant arms 40 which are connected between the outer circumference of the motor 38 and the inner wall of the cylindrical case 30.
• each arm 40 comprises an elongate portion 40a and a mounting portion 40b.
• the elongate portion 40a is of substantially aerofoil section and of a length sufficient to extend between the outer circumference of the motor casing and the inner wall of the cylindrical case.
• the mounting portion 40b extends substantially perpendicular to the elongate portion 40a and is provided with an arcuate slot 42.
• the arm 40 is connected to the motor by means of a screw or pin which extends through the arcuate slot 42 and into a mounting hole in the motor housing.
• a plurality of mounting holes 46 may be provided along a portion of the length of the motor housing, such that the arm 40 may be mounted at a selected one of a number of distances from the impeller.
• the arcuate slot 42 enables the angle of the elongate portion 40a of the arm 40 to be varied, as can be seen more clearly in Figure 6 of the drawings.
• the angle referred to in this case is the angle between a first axis (X) which is perpendicular to the length of the elongate portion 40a of the arm and a second axis (Y) which is perpendicular to the flange 32 of the cylindrical case 30.
• the mounting portion of the arm 40 is connected to the motor housing at the end of the arcuate slot 42 closest to the elongate portion 40a of the arm 40 and the arm 40 is at 90°.
• connection point between the mounting portion 40b of the arm and the motor housing has moved along the arcuate slot 42 in a direction away from the elongate portion 40a of the arm 40 and the arm 40 is at 75°.
• connection point has moved even further along the arcuate slot 42 in a direction away from the elongate portion 40a of the arm 40 and the arm 40 is at 60°.
• Figure 7 shows the relationship of velocities for an axial fan blade at a working point, and the three velocities to be considered are:
• this velocity is axial to the impeller.
• Figure 13 shows the force applied on the impeller blade.
• pressure of air is perpendicular to the surface of the impeller blade and creates a dynamic force oriented by the angle " ⁇ ".
• the support arms should be oriented at the same angle as a.
• fluctuation of the air is constant, whereas the direction is variable, so the angle a can only be estimated by using the relationship:
• the total efficiency of the fan can be increased by setting the angle of the support arms to match the direction of airflow, depending on the type of impeller and the angle of the impeller blades. It has been further observed that the total efficiency of the fan can be increased by changing the angle of the arms from 90° (prior art) to 60° as discussed above in relation to Figures 9 and 10 respectively. It has also been observed that, at least in some applications, the efficiency can start to drop again from an arm angle of around 55°. From these results, it is considered that, at least for some applications, the optimum arm angle may be 65° to 60°.
• the air flow direction along the length of the impeller blade may be located within an interval of, say; 15°.
• the airflow direction might be about 45° and the direction might change to about 60° further along the blade towards the motor, as illustrated in Figure 14.
• the arm 40 in one exemplary embodiment, might be twisted through, say, 15° along its length. Alternatively, as shown in Figure , the arm 40 could be bent by, say, 15° at, say, 3/3 of its full length. Whilst it is thought that the first embodiment ( Figure 3) might provide a solution closest to the ideal, the second embodiment ( Figure 4) may be more practical in terms of fabrication.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Geometry (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=39048084

Family Applications (1)

Country Status (5)

Cited By (11)

Families Citing this family (5)

Family Cites Families (17)

• 2007
  • 2007-12-14 GB GB0724355.3A patent/GB2455553B/en active Active
• 2008
  • 2008-12-15 WO PCT/GB2008/004131 patent/WO2009077737A2/en not_active Ceased
  • 2008-12-15 PL PL12195103T patent/PL2592281T3/pl unknown
  • 2008-12-15 ES ES12195103.2T patent/ES2561717T3/es active Active
  • 2008-12-15 EP EP12195103.2A patent/EP2592281B1/de active Active
  • 2008-12-15 EP EP08861453.2A patent/EP2225468B1/de active Active

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