Air blower

[57] ABSTRACT

An air blower for use in building heating systems which is designed to isolate noise and vibration from the building structure. The blower is further designed to allow for easy assembly and replacement of parts while installed in the building structure. The blower includes a housing which is mounted directly to the frame of the building. A fan wheel and motor assembly is positioned into the housing as a unit. The motor and fan assembly is supported by means of a flexible support system on the housing which isolates vibration and noise transmission. A Venturi plate is also suspended from the flexible support system and is otherwise isolated from the housing.

Claims, 7 Drawing Figures

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U.S. Patent Dec. 16, 1975 Sheet 1 of 2 3,926,537

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U.S. Patent Dec. 16, 1975 Sheet 2 of 2 3,926,537

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3,926,537

AIR BLOWER

This invention relates to air blowers. More specifically, this invention is directed to an improved air blower assembly for installation in building heating systems.

Heating systems have been developed for buildings which incorporate blowers separately mounted from the heating elements within the building structure. One such system is disclosed in Piper, U.S. Pat. No. 3,256,361. In the Piper system, the housing of the air blower is mounted directly to the building structure where it directs air through heat transfer coils. This mounting of the air blower directly to the building structure may tend to promote the transmission of noise and vibration throughout the building structure. An objectionable 60 cycle hum may result from such mountings in certain applications. Sixty cycles is the standard frequency for power companies. This frequency has been found objectionable by many people. As a result, the advantageous mounting of the blower assembly directly into the building structure has been compromised in certain installations by the resulting noise and vibration which may be transmitted through the building.

A further feature of blower assemblies which are mounted directly to building structures that detracts from the simplicity of such devices is the relatively detailed assembly procedure necessary to install or replace such air blower systems. This complication is further aggravatated by ceiling installations where it is necessary for the workman to position the blower assembly above his head.

The present invention contemplates an easily mounted blower which can be conveniently disassembled by separating three fasteners. Further, the moving components of the blower assembly are isolated from the remainder of the system to reduce noise and vibration.

Accordingly, an object of the present invention is to provide an air blower which reduces the transmission of noise and vibration from the system.

A second object of the present invention is to provide an air blower having a housing rigidly fixed to a building structure and an impellar and motor flexibly mounted to the housing to reduce noise and vibration.

Another object of the present invention is to flexibly mount the impellar and motor relative to a rigidly mounted volute to reduce noise and vibration.

A further object of the present invention is to provide a mounting system which flexibly supports a motor and impellar within a fixed housing on coil springs and provides lateral control of the impellar within the housing.

Another object of the present invention is to provide a Venturi plate which is flexibly mounted to the housing with the motor and impellar to reduce noise and vibration and allow easy assembly and removal of the motor and impellar from the installation.

A further object of the present invention is to provide an air blower system which may be easily assembled or disassembled by the placement or removal of three flexible mounts thereby allowing the placement or removal of the fan impellar, the motor, and the Venturi plate.

A further object of the present invention is to provide a flexible mounting system for a blower which can be used in both floor and ceiling installations.

Another object of the present invention is to provide an air blower which allows the disassembly of the impellar and motor from the housing without removing the housing from the building structure.

⁵ Thus, a flexible air blower assembly is provided which isolates vibration and noise and is easily assembled and disassembled in subassemblies for inspection and repair of moving parts.

Further objects and advantages will become apparent ¹⁰ from the description herein.

FIG. 1 is a top view of the present invention with a portion of the Venturi plate broken out to expose the impellar.

FIG. 2 is a front view of the present invention taken ¹⁵ in cross section along line 2—2 of FIG. 1.

FIG. 3 is a cross-sectional front view illustrating the positioning of the elements in a ceiling installation.

FIG. 4 is a cross-sectional detail of the mount and spring shown installed on a housing post.

²⁰ FIG. 5 is a detail of the extended support bracket on the mount taken along line 5—5 of FIG. 4.

FIG. 6 is a detail of the spring as it is mounted on the housing post taken along line 6—6 of FIG. 4.

FIG. 7 is a detail of the mount and spring assembly ²⁵ shown in the ceiling configuration.

Turning specifically to the drawings, a housing assembly generally designated 10 is illustrated. The housing assembly 10 includes a generally rectangular housing 12, a cover 14 and a volute 16. The rectangular ³⁰ housing 12 is conveniently made from sheet metal and has flanges 18, 20, and 22 for easy mounting to a building structure. Further, it is advantageous that the rectangular housing 12 be sized to fit between the standard floor or ceiling joists of a building. One contemplated ³⁵ application of the present invention is in a system such as disclosed in the Piper, U.S. Pat. No. 3,526,361. In such an application, a plenum is formed between joists with a blower at one end of the plenum, an outlet to the room at the other end of the plenum and a heat ex⁴⁰ changer somewhere between these two ends. With the present embodiment, the blower may actually provide the end of the plenum if it is spaced to fit between the building joists. Building joists are typically spaced 14% inches apart. Consequently, a convenient width for the ⁴⁵ rectangular housing 12 is 14¼ inches. The flanges 18 and 20 may then be positioned over the adjacent joists.

The top 14 is recessed from the upper edge of the rectangular housing 12 a convenient distance to allow for mounting brackets and the like, discussed below. A ⁵⁰ filter (not shown) may also be placed above the cover 14 and still remain within the top edge of the rectangular housing 12. The cover 14 has a large hole 24 extending therethrough. The hole 24 is large enough to accommodate the impellar and associated devices. Be⁵⁵ cause the hole 24 is large enough to receive the moving parts of the blower, the blower can be disassembled without the less convenient removal of the entire housing assembly. The hole 24 is also displaced from the center of the cover 14 in order that the volute 16 may ⁶⁰ extend across the entire width of the housing 12. Because the volute 16 is intended to separate from the impellar as it reaches the outlet, the moving parts of the blower must be displaced away from the outlet end of the volute 16 as best seen in FIG. 1. Consequently, the ⁶⁵ hole 24 in the cover 14 is displaced to one side of the housing 12.

The volute 16 may form an Archimedes spiral for efficient blower performance. The volute 16 is conve3,926,537 niently formed from a piece of sheet metal which extends from the bottom 26 of the rectangular housing 12 to the cover 14. For proper blower efficiency, it is advantageous to have the volute 16 fit against both the bottom 26 and the cover 14 in order that substantial air flow is not lost between these elements. The volute 16 terminates at a first end in a flat section 28 which extends to the front edge of the housing 12. The second end of the volute approaches one side of the housing 12 so that the housing 12 and the volute 16 intersect tangentially. The side of the housing 12 then extends parallel of the flat section 28 of the volute 16 to the edge of the rectangular housing 12. Thus, the air is directed out of the housing 12 between one wall thereof and the flat section 28.

The front wall 30 of the rectangular housing 12 need only extend to the cover 14. The wall 30 is not to be placed in front of the outlet formed by the side of the housing 12 and the straight section 28. Further, it is not necessary to cover the remainder of the front face because the remaining sides of the housing 12, the volute 16, and the cover 14 prevent pressure leakage from the pressurized space. A second front flange corresponding to front flange 22 may be positioned at the bottom of the front side 30 of the housing 12. By including both a first flange 22 and a second flange at the bottom of the housing 12, the first end of the plenum associated with this blower can be quickly and easily sealed by overlapping these front flanges with the top and bottom sides of the plenum.

The motive portion of the blower includes a motor 34 operably connected to an impellar 36. The motor 34 is of conventional design and is sized to fit within the impellar 36 so that a large annular space remains between the impellar 36 and the motor 34 for the flow of air into the central portion of the impellar 36. The output shaft 38 of the motor 34 extends from one end of the motor to engage the impellar 36.

The impellar 36 forms a cage consisting of a plate 40 at one end and an annular plate 42 at the second end. Vertically disposed blades 44 extend from the plate 40 to the annular ring 42 about the circumference of the impellar 36. The blades 44 are angled to give the desired pressure and volume relationship. The overall diameter of the impellar 36 is smaller than the diameter of the hole 24 in order that the impellar may be positioned within the housing assembly 10 after the volute 16 and cover 14 have been assembled. The height of the impellar 36 is such that it will fit between the bottom 26 and the top 14 of the housing assembly 10. It is advantageous to position the annular ring 42 of the blower 36 near the top 14 of the housing assembly 10 to prevent pressurized air from flowing from the pressurized area within the volute 16. The plate 40 of the impellar 36 structurally supports the impellar 36 on the motor output shaft 38. A collar 46 is keyed to the output shaft 38 and is held thereon by fastener 48. The collar 46 is centrally positioned on the plate 40. Support webs 50 may be employed to strengthen the unit.

Extended support means are provided for supporting the motor and impellar assembly within the housing assembly 10. One structural arrangement for providing such a support means is shown in the present embodiment as including a mounting plate 52 which fits onto the top of the motor 34. The mounting plate 52 is conveniently circular and has a central hole for accommodating the end of the shaft 38. Mounting studs 54 extend from the motor housing 34 through the mounting plate 52. Fasteners 56 retain the mounting plate 52 on the studs 54. Welded to the mounting plate 52 are arms 58. Each arm 58 consists of a formed rod having a lower section 60 extending from a position near the center of the mounting plate 52 to the outer periphery of the mounting plate 52. The lower section 60 is welded along its length to the mounting plate 52. Each arm 58 then extends upward along vertical section 62 in order that each arm may then extend outwardly and clear the cover 14 of the housing. The arm 58 extends out along section 64 to a mounting position on the cover 14. At the mounting position on the cover 14, the arm 58 forms a loop 66. The loop 66 has a fixed radius of curvature to accommodate the mounts which are discussed below. A ring 68 is welded to the rods of each arm 58. The ring 68 helps retain the outer extensions 64 of the arms 58 in the proper position to intersect the mounting points located about the housing assembly. Three arms 58 are shown in the drawings. Naturally, any number of arms may be employed. However, three arms are shown because this configuration has been found to be convenient and efficient. It is not essential to the present invention that rods be employed to form the arms 58. The extended support means may be formed from a single piece of material if such is found to be convenient.

A Venturi plate 70 is provided to advantageously direct air into the impellar 36. The Venturi plate is positioned on the arms 58 of the extended support means by brackets 72. Brackets 72 are welded or otherwise fixed to arms 58 and have a mounting hole therethrough. A fastener 74 may be employed with each bracket 72 to position the Venturi plate 70 against each bracket 72. Holes are provided in the Venturi plate 70 for accommodating the fasteners 74. The Venturi plate is positioned to clear the cover 14 of the housing assembly 10. This spacing between the cover 14 and the Venturi plate 70 is provided in order that noise and vibration is not transmitted from the Venturi plate 70 (which is associated with the impellar and motor assembly) to the housing assembly 10 through the cover 14. In blower assemblies of the present invention which are of a size that fits within the joists of a building, it has been found that the spacing between the Venturi plates 70 and the cover 14 can be as much as one-fourth inch without resulting in undesirable air flow therethrough. Larger spaces may also be equally as effective. However, one-fourth inch is sufficient in such blower sizes to insure that contact will not occur between the Venturi plate 70 and the cover 14 during operation of the unit.

By positioning the Venturi plate 70 on the arms 58, the entire motive subassembly of the blower may be removed with the extended support means. If the Venturi plate 70 were positioned on the cover 14, the impellar 36 could not be extracted from the housing without first removing the Venturi plate 70. The present embodiment is advantageous because insulations are often made in ceilings where the workman must work above his head to either install or replace the motor and impellar. Further, the housing and volute can remain in the installation during replacement of the motor and impellar. Consequently, the housing can be initially installed by simple, permanent means.

At each mounting point on the housing assembly 10, a mounting post 76 extends perpendicularly from the cover 14 to a center position in the loop 66 of each arm 58. The mounting post 76 may be conveniently

3,926,537 threaded at one end to accommodate a retaining nut. These posts 76 act to secure the extended mounting structure relative to the housing assembly 10.

Between the mounting posts 76 and the extended arms 58 are located flexible means for mounting the motor and impellar assembly 10. A mounting block 78 is provided with a coil spring 80 at each mounting post 76. The mounting block 78 is preferably of soft material such as soft rubber to better attenuate noise and vibration. The mount 78 has a collar 82 which extends about the middle of the block 78 and an axial hole 84 extends through the block 78. The hole 84 accommodates the mounting post 76 which is long enough to extend through the flexible means. The diameter of the hole 84 is larger than the diameter of the mounting post 76 in order that the block 78 will have room to move on the mounting post 76 to help attenuate noise and vibration. The block 78 includes a rounded upper end 86 extending upward from the collar 82 and a lower end 88 extending downward from the collar 82. The block is also of sufficient length to allow control over the orientation of the block 78 on the mounting post 76. The loop 66 on each arm 58 is sized to fit onto the upper end 86 at a circular groove 90. The circular groove 90 is adjacent the collar 82 in order that the loop 66 will rest on the collar 82 and be prevented from slipping downwardly on the block 78. The groove 90 is further provided in the rounded upper end 86 to prevent the arm 58 from slipping upward under large vibratory loads or outside stresses such as might occur during transportation and installation.

The coil spring 80 most conveniently includes a central section which is cylindrical. The inner diameter of the cylindrical section of the coil spring 80 is designed to fit snugly onto the lower end 88 of the mounting block 78. A groove 92 is provided for receipt of the uppermost turn of the spring 80. The groove 92 is positioned adjacent the collar 82 to prevent the spring 80 from slipping upwardly on the block 78. The groove 92 also prevents the block 78 from slipping away from the spring 80 under extraordinary load conditions. The lower end 88 is then tapered inward below the groove 92 to avoid interference with the spring 80. At the other end of the coil spring 80 the spring spirals to an eye 94. This eye 94 is sized to fit about the mounting posts 76. The coil spring 80 preferably has a low spring constant to further inhibit the transmission of vibration and noise.

Thus, a mounting block 78 is employed in conjunction with the loop 66 on the arm 58 and with the coil spring 80 to provide a flexible mounting on each mounting post 76. In a floor installation as specifically illustrated in FIGS. 2 and 4, the coil spring 80 rests on the cover 14. The mounting block 78 is supported by the coil spring 80 and the arm 58 is supported at the loop 66 on the mounting block 78. Collar 82 acts to separate the loop 66 from the coil spring 80 to prevent noise transmission there between and provide a larger base for both the loop 66 and the coil spring 80. A fastener 96 may be employed to insure that each mounting block 78 remains on each mounting post 76. In the floor installation, the eye 94 is not essential. In the ceiling installation as best seen in FIGS. 3 and 7, the flexible mounting assembly is again assembled as in the floor installation. However, the spring rests on the fastener 96 rather than on the cover 14. In this instance, the eye 86 supports the spring on the small diameter fasteners 96. When it is advantageous to use a simple cylindrical coil spring 80 without the eye 94, an oversized washer may be employed. The fastener 96 is shown as a blind end wing nut. The use of such a fastener causes the position of the fastener to be fixed relative to the post 76. In this manner the spacing between the fastener 96 and the cover 14 can be maintained. This spacing may be established so that the block 78 just touches either the cover 14 or the fastener 96 to prevent excessive travel of the unit which could damage the motor or impellar.

The flexible mounting assembly is described above as having snug fittings between the coil spring 80 and the mounting block 78 and between the mounting block 78 and the loop 66. These fittings are advantageous in that the assembly will not easily separate. This makes the placement of the motive subassembly of the blower less difficult because the various components will not fall off while the installation is being made. It is not essential that these components of the flexible mounting assembly tightly fit onto one another if large vibratory forces or changes in position are not anticipated.

Thus, a device is disclosed for flexibly mounting a motor and impellar assembly into a housing assembly for a blower which is rigidly placed in a building structure. The device permits easy installation and replacement of the motor and impellar components and provides a means for preventing the transmission of noise and vibration to the housing which is rigidly fixed within the building structure.

While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein described. The invention, therefore, is not to be restricted except as is necessary by the prior art and by the spirit of the appended claims.