US 3486688 A
Description (OCR text may contain errors)
H; E. HOFVENDAHL v 3,486,688
FURNACE BLOWER INSTALLATION Dec. 30, 1969v 3' Sheets-Sheet 2 Filed June 20, 1968 Fig.4
Attorneys 5 Sheets-Sheet 5 Dec. 30, 1969 H. E. HQFVENDAHL FURNACE BLOWER INSTALLATION Filed June 20. 1968 F I g I I B HerberrE United States Patent 3,486,688 FURNACE BLOWER INSTALLATION Herbert E. Hofvendahl, 6 Corte Sombrita, Orinda, Calif. 94563 Filed June 20, 1968, Ser. No. 738,451 Int. Cl. F04b 39/00; F16m 1/04 US. Cl. 230-235 12 Claims ABSTRACT OF THE DISCLOSURE A blower installation for mounting a base of the blower to a bulkhead or other support structure of forced air furnaces and air conditioners is disclosed. The base includes parallel, spaced flanges which rest on elongate, parallel rails or bearing members secured to a resilient, oscillation dampening material mounted on the bulkhead to prevent the transfer of vibrations from the blower to the bulkhead and the support structure. The blower base can be slideably engaged with the rails to facilitate the ease with which the blower is placed on and removed from the bulkhead. A plurality of spaced arms are secured to the bulkhead and the blower base, which arms have at their free ends resilient bumpers mounted thereon which engage the bulkhead or the base in an oscillation dampening manner and which prevent relative movement of the base away from the supporting rails while permitting slideable relative movements between the flanges of the base and the rails of the bulkhead. Means are preferably also provided for demountably and flexibly securing the base to the bulkhead without transferring vibrations from the blower to the bulkhead.
BACKGROUND OF THE INVENTION The present invention relates to blower installations and more particularly to such installations which mount the blower in a furnace, air conditioner or other heating or air conditioning equipment in a vibration dampening manner while permitting slideable movement between the blower and such equipment to place the former in or remote it from such equipment.
Conventional forced air furnaces provide a housing which is partitioned by a bulkhead into a heat exchanger chamber, containing a heat exchange unit, and a fresh air supply chamber, housing a motor operated impeller or blower for supplying fresh air into the heat exchanger of the furnace. The bulkhead includes an opening over which the blower is mounted and through which the fresh air enters the heat exchange chamber of the housing. To facilitate the ease with which the blower is installed or removed during the initial assembly of the furnace and for subsequent maintenance and repair work, prior art furnaces have been devised which mount the blower on parallel, elongate rails secured to or forming an integral part of the bulkhead. The blower includes flanges which rest on the rails and thus support it on the bulkhead.
During operation of the furnace, the impeller of the blower rotates at a relatively high speed and causes substantial vibrations. Ordinarily the vibrations are transmitted to the furnace structure which causes excessive and disturbing noise. The noise is frequently transmitted through heating ducts connecting with the furnace to remote rooms of the building or house in which the furnace is installed. To reduce the adverse efiects of the blower vibrations, it has been suggested to place the blower on rails or bearing members which are isolated from the bulkhead by resilient materials. Such a blower installation is disclosed in US. Patent No. 2,464,473.
The installation disclosed in the above referred to patent substantially reduces the adverse effect from blower vibrations. The blower, however, rests on the support rails by its own weight and no provisions are made to secure it to the supporting bulkhead since a fixed interconnection between the bulkheads and the blower substantially reduces the beneficial effects obtained from the resilient mounting of the blower. To positively secure the blower to the resiliently mounted rail or bearing member is difficult or impossible without losing the advantages obtained from the sildeable interengagement of the flanges of the blower and the rails of the bulkhead. Consequently, the blower can vibrate so that the flanges alternately become disengaged and then engaged with the rails. The resiliently mounted rails have a tendency to accentuate such movement or vibrations of the blower which can result in damage to the furnace or the blower and in excessive noise.
Another technique which has previously been used is to mount the blowers on relatively large rubber blocks secured to the support structure. Excellent results have been obtained with such installations since they dampen the vibrations and virtually eliminate noise therefrom. However, it is a relatively expensive blower installation both in terms of its initial cost and the cost of disassembling the blower from the mounts. Its use is, therefore, limited to large, industrial blowers for furnaces or cooling units servicing large buildings.
Thus, the prior art does not provide fully satisfactory low cost installations for furnace blowers.
SUMMARY OF THE INVENTION The present invention provides a low cost, vibration dampening which positively constrains the blower to the support structure of the equipment in which it is mounted. Briefly, the installation comprises a support structure, resilient means secured to the structure and a support rail or bearing member secured to the resilient means for dampening vibrations of the rail when subjected to cyclical forces from the blower. The blower includes a mounting flange extending from the blower and slideably contacting the rail for supporting the blower on the rail. Holding means interengaging the support structure and the blower are provided for preventing the disengagement nf the flange and the rail and for dampening vibrational movement of the flange while the blower is in operation.
The blower installation of the present invention is adapted for use in conjunction with all furnaces, air conditioners, and heating equipment (herein referred to as furnaces) having a bulkhead between two furnace chambers, irrespective of whether the blower is mounted above or below the heat exchanger of the furnace. The holding means preferably comprise a plurality of spaced arms secured to the blower base or the bulkheads supporting the blower and having at their free ends resilient parts to provide the interconnection between the blower and the bulkhead. The resilient parts and the arms are formed to prevent all movements of the blower, in response to vibrations of its impeller, away from the supporting rails and to simultaneously enable the slideable engagement of the blower with the support rails of the bulkhead. The advantages of an easy, effortless and time saving installation and removal of the blower are thereby retained while the transfer of undesirable vibrational movement from the blower to the bulkhead and the remaining support structure have been eliminated. This permits a virtually noiseless operation of the furnace.
The present invention employs simple, mass produceable and, therefore, inexpensive parts to subdue the vibrations of the blower. The assembly and installation of the vibration dampening components is easy and quickly performed and is, therefore, economical. The advantages of a noise free operation and a positive mounting of the blower are thus, for the first time, available on low cost,
home type furnaces. In addition, this invention enables prior art furnaces to be equipped with the vibration dampening means.
BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a front elevational view of a counter flow furnace having a blower installed on top of its heat exchanger in accordance with the present invention;
FIGURE 2 is a side elevational view taken on line 22 of FIGURE 1;
FIGURE 3 is a plan view, in section, taken on line 3-3 of FIGURE 1;
FIGURE 4 is a fragmentary, enlarged view, in section, taken on line 4-4 of FIGURE 3;
FIGURE 5 is a fragmentary, enlarged view, in section, taken on line 55 of FIGURE 3;
FIGURE 6 is a fragmentary plan view, in section similar to FIGURE 3 and showing another embodiment of this invention;
FIGURE 7 is a fragmentary, enlarged view, in section, taken on line 77 of FIGURE 6;
FIGURE 8 is a front elevational view, similar to FIG- URE 1, of an upflow furnace having a blower installed in accordance with the present invention;
FIGURE 9 is a bottom view, in section, taken on line 99 of FIGURE 8;
FIGURE 10 is a fragmentary, enlarged cross sectional view taken on line 1010 of FIGURE 9; and
FIGURE 11 is a fragmentary, enlarged, cross sectional view taken on line 1111 of FIGURE 9.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGURES 1 and 2, a counter flow furnace 12 comprises a housing 14 divided by a bulkhead 16 into an upper fresh air intake chamber 18 and a lower heat exchanger chamber 20. Mounted in the heat exchanger chamber is a burner 22 which communicates with a heat exchanger 24 and a flue 26 through which exhaust gases from the burner are discharged. Although the present invention is described in conjunction with a warm air furnace, it is as above indicated used with equal success for air coolers. In such a case, the burner is replaced by a cooling or refrigeration unit (not shown) which communicates with the heat exchanger.
Fresh air intake chamber 18 communicate with the exterior of the furnace through a filter element (not shown) and houses a blower 30 which is secured to bulkhead 16. The blower includes an intake opening 32 and rotatably mounts an impeller 34 driven by an electric motor 36 via belt 28. Alternatively, a motor connected directly to the impeller may be provided.
Referring to FIGURES 3 through '5, bulkhead 16 is defined by four rectangularly shaped sheet metal sections 40, 41, 42 and 43, which may best be seen in FIGURE 3, and these sections define an opening 44 in the bulkhead communicating the fresh air intake chamber of the furnace with the heat exchanger chamber thereof. Ends 45 of sheet metal sections 41 and 42 defining the opening in the bulkhead are Z-shaped and offset (see FIGURE 4) and support an elongate strip 46 of a resilient material, such as plastic foam or foam rubber. Alternatively, strip 46 may be replaced by a leaf spring formed of spring steel, coil springs or other types of springs formed of various material. The elongate strips are preferably bonded to Z- shaped ends 45 and support elongate, L-shaped bearing members or rails 48 bonded to the strips of resilient material. Thus, the rails are parallel, and spaced from each other and preferably extend over the full length of the sheet metal sections.
The sheet metal sections of the bulkhead are a portion of the support structure of the furnace and are secured to side panels 50 defining housing 14 of the furnace. A front panel 52 (FIGURE 2) is demountable to provide access to blower 30. Upon removal of front panel 52, flue 26 can be pulled down and out of bulkhead 16 and the blQWer removed. The blower is mounted on a base 54 which has a width about equal to the spacing between the L-shaped rails 48 and which includes parallel angles 56 having flanges 58 of a length equal to that of the L-shaped rails. The base, and the blower, is installed in the furnace by placing the flanges of the angles on top of L-shaped rails 48 and slideably moving the base and the blower relative to the rails until a forward end 60 of the angles engages the interior sheet 43 of the bulkhead 16. In the past, no additional means for connecting the base and the blower to the bulkheads of the furnace were provided. The base was simply left in this position, the motor was connected with a source of electric power and operated. This resulted in the above referred to vibrational movements of the base off the resiliently mounted L-shaped rails 48.
To constrain the base and the blower to the bulkhead and minimize or prevent virbational movement of the base while the blower is in operation, a pair of elongate arms 64 are secured to sheet metal sections 41 and 42 adjacent rear panel 51 of the housing 14. Free ends 66 of the arms have mounted thereon resilient bumpers 68 with rivets 70 or by bonding the bumpers to the arms. The bumpers are preferably cylindrical or frusto-conically shaped, commercially available rubber bumpers to minimize their cost. In the alternative, however, the bumpers may have any other desired configuration. End faces 72 of the bumpers are directed toward the adjacent L-shaped rails 48 and are spaced therefrom a distance about equal to the thickness of flanges 58 of angles 56 secured to base 54. To increase the vibration dampening effectiveness of bumpers, they are preferably positioned so that their spacing from the L-shaped rails is slightly less than the thickness of the flanges of the angles to provide for an interference between the rails, the end faces of the bumpers, and the flanges when the base and the blower are supported by bulkhead 16.
Referring to FIGURES 3 and 5, a pair of Z-shaped arms 74 are secured to a forward end 75 of base 54. Arms 74 and rubber bumpers 68 are mounted for engagement of their end faces 72 with sheet metal section 40 of bulkhead 16. The Z-shaped arms extend past the bumpers to allow mounting of threaded bolts 78 or sheet metal screws through a bore (not shown) in sheet metal section 40. The Z-shaped members, base 54 and blower 30, are thereby flexible connected with the bulkhead to prevent relative sliding motions between the base and the L-shaped rails without transmitting vibrations from the base to the bulkhead. When bolts 78 or screws are employed, the ends 76 of arms 74 afford a flexible connection between the bulkhead and blower in that the inherent resiliency in arm 76, as cantilevered from base 54, allows movement of the base 54 relative to bulkhead 16. The Z-shaped arms and the bumpers mounted thereon provide further vibration dampening support for the base and the blower.
In use, and when impeller 34 vibrates due to its imperfectly balanced mass, a base 54 is at all times maintained in firm contact with bulkhead 16 through the vibration dampening strips 46 on the one hand and the vibration dampening bumpers 68 on the other hand. The base can neither move up nor down relative to the bulkhead without depressing either the resilient strip or the resilient bumpers. The depression of the resilient materials minimizes or eliminates the transfer of vibrational movements of the blower and the base to the remainder of the furnace. Noise as well as vibrational movements of portions of the furnace, such as bulkhead 16, are virtually eliminated.
Referring to FIGURES 6 and 7, another embodiment for the mounting of blower 30 in a counterfiow furnace is illustrated. Bulkhead 16a is constructed identically to bulkhead 16 shown in FIGURE 3 and comprises sheet metal sections 40a, 41a, 42a and 43a. Sections 41a and 42a include strips 46a of a resilient material and L- shaped rails 48a bonded to the strips. Pairs of arms 80, constructed similarly to arms 64 shown in FIGURES 3 through 5, are secured to sheet metal sections 41aand 42a adjacent their respective ends. Rubber bumpers 82 face toward flanges 58a of angles 56a to secure the base and the blower to the bulkheads in the same manner as do arms 64 and 74. In FIGURE 7 it will be noted that the surface of member 48a is flush with the surface of sheet metal section 4011 so that the flange 58a can be slid over fixed member 40a under the bumper 82. In FIG- URE 5, by contrast the top surface of member 48 is not on the same level as member 40, but the construction and location of arms 74 allows for such a stepped relationship between the surfaces. A similar stepped construction can be achieved in the blower mount of FIG- URES 6 and 7 if front arms 80 are demountably attached to sections 41a and 4201 after the blower is slid into position.
Referring to FIGURE 8, an upflow furnace 86 is illustrated which includes an upper heat exchanger chamber 87 and a lower fresh air chamber 88 which are separated by a bulkhead 90. Burner 91 and a heat exchanger 92 are disposed in the upper chamber of the furnace while the lower chamber houses a blower 94 having an impeller (not shown in FIGURE 8) driven by an electric motor 95 via a belt 96. In contrast to the counterflow furnace shown in FIGURE 1, blower 94 is suspended from bulkhead 90 and hangs downwardly thereof. The blower draws fresh air through a filter unit (not shown in FIG- URE 8), forces it past heat exchanger 92 and into ducts (not shown).
Referring to FIGURES 9 through 11, bulkhead 90 is formed by four sheet metal sections 98, 99, 100 and 101 which define an opening 102 connecting the heat exchanger chamber of the furnace with the fresh air chamber. The sheet metal sections are secured to side panels 104 of the furnace and a removable front panel provides access to opening 102 and the blower.
Free ends 103 of sheet metal sections 99 and 100 are Z-shaped, in a manner similar to ends 45 of sections 41 and 42, shown in FIGURES 3 and 4, and include a strip 108 of a resilient material bonded thereto. L-shaped rails 110 are bonded to the upper side of the strips of resilient material and support flanges 112 of elongated, space apart angles 114 secured to a blower mounting base 116. Again, in accordance with the prior art, the blower and the base mounting it are retained on the L-shaped rails by their own weight. This results in noise and possible damage to the furnace from the vibrating blower.
To minimize and eliminate vibrations of the operating blower sheet metal arms 118 are secured to an upper side 120 of sections 99 and 100 and have free ends formed to project over flanges 112 supported by L-shaped rails 110. Rubber bumpers 122 are mounted on arms 118 facing toward and engaging the flanges in the above described manner.
In addition, Z-shaped brackets 124 are secured to base 116 adjacent its end 126 which is adjacent the front opening in the fresh air chamber and are arranged to project outwardly and downwardly of the base over an end portion 128 of sheet metal sections 99 and 100. The brackets have rubber bumpers 123 mounted thereon at their central portion and are shaped so that end faces 129 of the bumpers engage the end portions 128 of the sheet metal sections, thereby biasing flanges 112 of angles 114 into engagement with L-shaped rails 110. In this manner, vibrational movement of base 116 while blower 94 operates are dampened and minimized to virtually eliminate attendant noise.
As may best be seen in FIGURE 9, sheet metal panel 101 overlaps the front end 126 of the blower base 116. Accordingly, the furnace blower mount of the present invention may be constructed by eliminating bumpers 123 and 133 and positioning a bumper (not shown) on the top side of base 116 so as to engage the bottom surface of panel 101.
It is often desirable to connect the blower with the supporting structure of the furnace. For this purpose, an L-shaped bracket 130 projects from the underside of sheet metals sections 99 and of bulkhead 90 opposite a vertical end portion 132 of Z-shaped brackets 124 having a resilient bumper 133 mounted thereon. A threaded bolt 134 connects the L-shaped bracket and the vertical portion of bracket by urging bracket 130 against bumper 133. The ability of bolt 134 to move transversely of its longitudinal axis and bumper 133 to shift relative to bracket 130 affords a flexible connection which also prevents a direct metal to metal contact and transmission of vibrations from the blower to the bulkhead, as would be the case if the two brackets were tightly secured to each other. The effectiveness of the vibration absorbing installation of this invention is thereby maintained It should be noted that in all embodiments of this invention the blower mounting base, and more particularly the angles supporting the base on the resiliently mounted L-shaped rails of the bulkheads, is firmly urged by vibration absorbing members against vibration away from the rails. Uncontrolled motions of the vibrating blower and base are, therefore, not possible. At the same time, this invention retains the time saving and economic slideable mounting of the base on the bulkhead of the furnace. Aside from its above described general utility, this inven tion also enables the low-cost rebuilding of prior art furnaces, which have blowers supported on the bulkheads by their weight only, into furnaces wherein the blowers are positively constrained to the bulkheads. The task requires no more than the installation of the arms carrying the resilient bumpers or bumpers alone so that the latter cooperate with the blower, or the base, and the bulkhead, including the L-shaped rails.
1. A blower installation comprising, a support structure including an elongate rail, resilient means intermediate the structure and the rail for absorbing vibrations of the rail when subjected to cyclical forces and a bulkhead; a blower including an elongate mounting flange slideably contacting the support rail to support the blower on the rail; and holding means interengaging the support structure and the blower to prevent the disengagement of the flange and the rail and to absorb vibrational movement of the flange in a direction away from the rail.
2. A blower installation aceording to claim 1, including demountable means for securing the blower to the support structure to prevent relative slideable motions between them, the demountable means being constructed to prevent direct contact between a portion of the blower and the support structure.
3. A blower installation according to claim 1, wherein the holding means comprise an arm and a resilient part secured to the arm and engaging a portion of the blower.
4. A blower installation according to claim 3, wherein the holding means comprises a plurality of spaced arms adjacent overlapping portions of the blower and the support structure.
5. A blower installation according to claim 1, wherein the holding means comprise arms secured to the support structure and extending over the rail in a spaced relation therefrom, and a resilient part mounted on the arms to face the rail and engage the flange to absorb relative motions of the flange away from the rail.
6. A blower installation according to claim 5 including additional arms secured to the blower and extending over the support structure in a spaced relation, and resilient parts secured to the additional arms to face and engage the support structure and absorb relative motion of the blower.
7. A blower installation according to claim 6, wherein the additional arms and resilient parts are mounted adjacent the flange and arranged to permit the rails and the resilient means to be disposed intermediate the flange and the additional arms.
8. A blower installation according to claim 6, wherein the blower includes a pair of spaced apart, parallel flanges on sides of the blower and the additional arms and resilient parts engage a side of the support structure which is transverse to said flanges.
9. A blower installation according to claim 6 including means for flexibly securing the blower to the support structure and for preventing relative slideable movement between them.
10. A blower installation comprising (a) a support structure,
(b) a pair of parallel support rails mounted on the structure and isolated therefrom by resilient, vibration absorbing means,
(0) a blower base including parallel spaced apart flanges formed to slideably engage and support the blower on the rails,
(d) holding means including a plurality of spaced apart arms mounting resilient parts which interconnect the base with the support structure for preventing movement of the flanges away from the rails in a vibration absorbing manner, the arms and the resilient parts being formed to permit the slideable interengagement of the flanges, the rails and the resilient means, and
(e) means for demountably securing the base to the support structure to prevent relative sliding motion between them.
11. A blower installation according to claim 10, wherein the blower is suspended from and positioned below the rails and the holding means cooperate and are in engagement with the rails and the flanges.
12. A blower installation according to claim 10, wherein the blower is positioned above the rails, some of the arms and resilient parts cooperate with the rails and the flanges some of the arms and the resilient parts are positioned to engage a side of the support structure which is transverse to the rails, and wherein the means for demountably securing the base to the support structure cooperate with said last mentioned arms and the support structure.
References Cited UNITED STATES PATENTS ROBERT M. WALKER, Primary Examiner US. Cl. X.R.