FIELD OF THE DISCLOSURE
The present disclosure relates generally to air coolers and, more specifically, to an air cooled heat exchanger including a direct drive fan mounted with an X-brace assembly.
BACKGROUND OF THE INVENTION
Heat exchangers are widely used for cooling or heating process fluid streams using a second cooling or heating fluid stream. Air-cooled heat exchangers, as the name implies, use air as the second cooling fluid and typically employ a fan to drive the air over tube bundles through which the process fluids being cooled flow. Such heat exchangers may be of the induced draft heat exchanger type or the forced draft heat exchanger type. Induced draft heat exchangers feature tube bundle(s) located on the suction side of the fan (with the fan typically positioned above the bundle). Forced draft heat exchangers feature tube bundle(s) located on the discharge side of the fan (with the fan typically positioned below the bundle). The tube bundles are typically organized in bays with each bay containing one or more tube bundles serviced by one or more fans. Each bay also includes the structure for holding the tube bundle(s), fan(s), plenum(s) and other attendant equipment.
An example of a prior art forced draft heat exchanger bay is indicated in general at 10 in FIG. 1 and includes a fan 12 which is powered by a fan motor and drive assembly 14, which are supported by a machinery mount 15. The drive assembly 14 typically provides indirect drive of the fan by the motor via a drive belt or chain that engages and extends between sheaves or sprockets mounted to the motor drive shaft and the fan central shaft. To focus and direct air flow, a fan ring 16 circumferentially surrounds the fan. A tube bundle 22 and a plenum 24 are positioned above the fan, where the latter equalizes air pressure for more even distribution of the air flow from the fan across the tube bundle. A header 25 featuring nozzles 26 directs a process fluid stream into and out of the tube bundle so that the process fluid stream is cooled by the air flow generated by the fan. Support columns 28 support the bay in an installation.
In addition, cooling devices featuring a direct-drive fan and motor assembly mounted within the cooling device using radially extending arms or legs are disclosed in U.S. Pat. No. 10,968,920 to Cothave et al. and U.S. Pat. No. 7,880,348 to McElveen et al. Cothave et al. further shows that it is known to position such a fan assembly adjacent to a heat exchanger for induced or forced air cooling. These references, however, disclose mounting the fan and motor assembly directly to a fan deck or a shroud.
Weight reductions and strength increases in air-cooled heat exchangers are desirable to provide more secure and economical transport and reductions in material costs. Weight reductions, however, should not come at the expense of structural integrity and ideally should reduce complexity.
SUMMARY
There are several aspects of the present subject matter which may be embodied separately or together in the devices and systems described and claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to preclude the use of these aspects separately or the claiming of such aspects separately or in different combinations as set forth in the claims appended hereto.
In one aspect, an air-cooled heat exchanger includes a plenum. A fan ring is positioned adjacent to the plenum and has a fan ring opening. Support columns are configured to support the plenum and the fan ring on a support surface. An X-brace assembly includes a motor mount and a number of leg members extending radially from the motor mount with each one of the leg members connected to a single corresponding one of the support columns so that the leg members extend between the motor mount and the support columns. A motor is mounted to the motor mount of the X-brace assembly and includes a drive shaft. A fan has a number of fan blades with each of the fan blades mounted to the drive shaft of the motor so that the fan blades radially extend from the drive shaft. The fan is positioned within the fan ring between the motor and the fan ring opening.
In another aspect, an X-brace assembly for mounting a fan motor to an air-cooled heat exchanger supported by a number of support columns includes a motor mount configured to attach to and support the fan motor. Leg members extend radially from the motor mount with each one of the leg members configured to be connected to a single corresponding one of the support columns so that the leg members extend between the motor mount and the support columns.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of a prior art air-cooled heat exchanger bay.
FIG. 2 is perspective view of an embodiment of the air-cooled heat exchanger of the disclosure.
FIG. 3 is a perspective view of the air-cooled heat exchanger of FIG. 2 with the tube bundle omitted.
FIG. 4 is an exploded perspective view of the air-cooled heat exchanger of FIG. 3.
FIG. 5 is an enlarged partially exploded perspective view of the X-brace assembly of the air-cooled heat exchanger of FIGS. 3 and 4.
FIG. 6 is an enlarged perspective view of the exploded portion of FIG. 5.
FIG. 7 is an enlarged perspective view illustrating an attachment of the distal end of a leg of the X-brace assembly by a bracket to a support column of the forced draft air cooler of FIGS. 3 and 4.
FIG. 8 is an exploded perspective view of the motor mount of FIGS. 3 and 4.
FIG. 9 is an enlarged perspective view of the motor mount and X-brace assembly of FIG. 9 including a view of the motor mount with two adjacent side panels omitted illustrating installation of the motor into the motor mount and installation of the motor mount into the X-brace assembly.
FIG. 10 is a side perspective view of the motor mount of FIGS. 3, 4 and 9 mounted within the X-brace assembly.
FIG. 11 is a bottom perspective view of the motor mounted within the motor mount of FIGS. 3, 4, 9 and 10.
FIG. 12 is a perspective view of the X-brace assembly of FIG. 5 and an exploded view of an alternative embodiment of the motor mount and the motor.
FIG. 13 is a perspective view of the X-brace assembly, motor mount and motor of FIG. 12 after assembly.
DETAILED DESCRIPTION OF EMBODIMENTS
While the technology of the disclosure is described below in terms of a forced draft air-cooled heat exchanger, it may alternatively be employed with an induced draft air-cooled heat exchanger.
An embodiment of the air-cooled heat exchanger with X-brace drive of the disclosure is indicated in general at 30 in FIG. 2. The heat exchanger includes a tube bundle 32 positioned on top of a plenum 34. A fan ring 36 is mounted to the bottom of the plenum, and features a fan ring opening that is a bottom opening, illustrated at 35 in FIG. 4, surrounded and defined by the bottom edge of the fan ring. As described in greater detail below, a fan is housed within the fan ring 36. Support columns 38a, 38b, 38c and 38d are mounted to the four corners of the plenum and tube bundle and support the heat exchanger. Each support column may be provided with a pair of struts, such as struts 42 and 44 secured to support column 38a.
The heat exchanger 30 of FIG. 2 is illustrated and indicated in general at 30 in FIGS. 3 and 4 with the tube bundle removed so that the interior of the plenum, indicated in general at 34, is visible. The plenum 34 features side panels 46a, 46b, 46c and 46d extending between corresponding support columns. Tube bundle supports 48a, 48b, 48c and 48d are mounted to, and extend upwardly from, the support columns. An X-brace assembly 52 is connected to each support column 38a-38d, as described in greater detail below, and includes a centrally positioned motor mount 54. A support member 56 (FIG. 3) may extend between plenum sides 46b and 46d to add further rigidity.
As illustrated in FIG. 4, the side panels 46a-46d of the plenum may be secured to neighboring column supports 38a-38d by fasteners (where the apertures that receive the fasteners are illustrated). A plenum floor 58 is secured at its corners to support columns 38a-38d and is also fastened to the bottom edges of the plenum side panels 46a-46d. A circular central opening 62 is formed in the plenum floor 58 with the fan ring 36 circumferentially secured along or about the opening, also by fasteners. Welding or other attachment arrangements known in the art may be substituted for the fasteners noted above and below.
With reference to FIGS. 4 and 5, the X-brace assembly, indicated in general at 52, includes first and second central plates 64 and 66 which sandwich the proximal ends of four leg members 68a, 68b, 68c and 68d so that the four leg members radially extend from the central plates. As an example only, the first and second central plates 64 and 66 may be secured to the proximal ends of the four leg members by fasteners.
As best shown in FIG. 5, mounting brackets 72a, 72b, 72c and 72d (where 72a, 72b and 72d are indicated in general) are mounted to the distal ends of each of the four leg members 68a, 68b, 68c and 68d, respectively. As illustrated in FIG. 6, where an enlarged and exploded view of mounting bracket 72d (indicated in general) is provided, the mounting bracket includes a bracket mounting plate 74d connected to upper and lower bracket plates 76d and 78d. As an example only, the top edge of the bracket mounting plate 74d may be welded to edge 79d of upper bracket plate 76d and the bottom edge of the bracket mounting plate may be welded to edge 81d of lower bracket plate 78d. A central support plate 82d is sandwiched between and welded to the parallel upper and lower bracket plates 76d and 78d by its top and bottom edges preferably in an orientation generally perpendicular to the bracket mounting plate 74d and the upper and lower bracket plates 76d and 78d. An inner edge 84d of the central support plate 82d also is preferably welded to the bracket mounting plate 74d. The assembled bracket components are illustrated for mounting brackets 72a and 72b in FIG. 5.
As illustrated in FIG. 6, a leg mounting plate 84d, which may be welded to the distal end of leg 68d, has openings 86d that correspond with openings 88d of bracket mounting plate 74d. As a result, fasteners, such as nuts and bolts, may be used to attach mounting bracket 72d to the leg mounting plate 84d, and thus the distal end of leg 68d.
As examples only, leg members 68a-68d may feature an I-beam construction and be formed from carbon steel.
As illustrated in FIG. 7, support column 38d (as also illustrated in FIG. 4) features, as examples only, an I-beam construction and may be made of carbon steel (with the same construction applying to the remaining support columns). The upper and lower bracket plates 76d and 78d of the mounting bracket 72d are shaped so as to fit between the parallel portions or sides of the I-beam of support column 38d so that the mounted bracket may be welded into the position illustrated in FIGS. 7 and 4. The remaining mounting brackets 72a, 72b and 72c are welded to support columns 38a, 38b and 38c, respectively, in the same manner. As a result, the X-brace assembly 52 is directly connected to the support columns 38a-38d.
Turning to FIG. 8, an embodiment of the motor mount of the air-cooled heat exchanger with X-brace drive of the disclosure takes the form of a motor mount housing, indicated in general at 90, and includes motor mount side panels 92a, 92b, 92c and 92d as well as a motor mount plate 94. The side edges of the side panels 92a-92d may be welded together. Each of the side panels 92a-92d has an inwardly projecting upper flange at the top edge, as indicated at 96 for panel 92a. The motor mount plate 94 features peripheral openings 98 that align with corresponding openings of the flanges of the motor mount side panels 92a-92d so that the motor mount plate may be attached to the side panels by fasteners, such as nuts and bolts 99 and 101 illustrated in FIG. 9, so that a motor mount box or housing is formed. The motor mount plate 94 further includes motor mount apertures 102 whereby a fan motor may be mounted to the motor mount plate. Slots, such as slot 104 illustrated for side panel 92a, are provided in each motor mount side panel to provide cooling for a motor positioned within the motor mount as well as access for power cables.
As illustrated in FIG. 9, an electric fan motor 108 is mounted via motor brackets 112 and fasteners, such as nuts and bolts 114 and 116, to the motor mount plate 94, where the nuts and bolts engage the motor mount apertures 102.
As illustrated in FIGS. 8 and 9 for motor mount side panels 92b and 92c, each motor mount side panel has an inwardly projecting lower flange 118b and 118c at the bottom edge. As illustrated for lower flanges 118b and 118c in FIG. 8, each lower flange is provided with apertures 124b and 124c with align with corresponding apertures, such as aperture 126 of FIG. 9, formed in the second central plate 66. As a result, as illustrated in FIGS. 9 and 10, the motor mount housing 90 may be secured within an opening 128 formed in the first central plate 64 by fasteners, such as nuts and bolts 132 and 134 (FIG. 9).
With reference to FIG. 11, when the fan motor 108 is mounted within the motor mount housing 90, and the motor mount housing 90 is mounted to the second central plate 66 (of the X-brace assembly 52 of FIG. 5), the open bottom of the motor mount housing 90 is aligned with an opening 136 (FIGS. 9 and 11) formed in second central plate 66. As illustrated in FIG. 3, fan blades 120 are attached to the drive shaft 122 (FIGS. 9 and 11) of the fan motor by their proximal ends via a hub 123 so that they extend from the hub in a radial fashion. As a result, as illustrated in FIG. 3, the fan motor is mounted within the plenum 34 above the fan and fan ring 36.
Fan motor 108 is preferably a high efficiency transverse flux motor so that sufficient horsepower is provided to turn the large fan blades (120 of FIG. 3) while also providing a reduced motor weight. Such fan blades, as an example only, may provide the fan with a blade tip to blade tip diameter of five feet or more. As an example only, a suitable fan motor is illustrated in U.S. Pat. No. 9,618,003 to Janecek et al., the contents of which are hereby incorporated by reference.
An alternative embodiment of the motor mount is presented in FIGS. 12 and 13. The X-brace assembly, indicated in general at 152 in FIGS. 12 and 13, has the same construction as the X-brace assembly 52 described above with reference to FIGS. 3-6. The motor mount of FIGS. 12 and 13, however, takes the form of a face mount plate 154.
As illustrated in FIG. 12, the face mount plate 154 includes a central opening 156 through which the drive shaft 122 of the electric fan motor 108 passes. The face mount plate 154 also includes fan mounting apertures 158 which receive fasteners (such as bolts) to secure the motor 108 to the face mount plate 154 in the position shown in FIG. 13. As illustrated in FIG. 12, the face mount plate 154 further includes peripheral apertures 162 that align with corresponding apertures 163 formed in the second central plate 166, when the face mount plate is in the position illustrated in FIG. 13, so that fasteners (such as screws 168 of FIG. 12) may be used to secure the face mount plate to the lower central plate. Of course, fasteners other than screws 168 and/or welding may be used to secure the face mount plate 154 to the second central plate 166.
As illustrated in FIG. 13, central side panels 172a-172d may be secured between the first central plate 164 and the second central plate 166, such as by fasteners or welding.
Use of the face mount plate 154 of FIGS. 12 and 13 to mount the motor 108 within the X-brace assembly 152 allows for enhanced airflow over the motor for cooling of the motor.
In an alternative embodiment, where the air-cooled heat exchanger with X-brace drive of the disclosure is an induced draft heat exchanger, the tube bundle(s) are located on the suction side of the fan (with the fan positioned above the bundle). More specifically, in such an embodiment, the support columns extend downwards from the tube bundle (which is now on the bottom of the heat exchanger). Furthermore, the plenum would be positioned above the tube bundle with the fan ring extending upwards from the top surface of the ceiling of the plenum with the fan ring opening being a top opening surrounded and defined by the top edge of the fan ring. The X-brace assembly and fan motor would be positioned below the tube bundle, with the drive shaft extending up through the tube bundle layer and plenum to the fan positioned in the fan ring. As a result, the motor is kept cool in the cold air stream.
Embodiments of the forced draft heat exchanger with X-brace drive described above tie in the vertical support columns for the unit to the fan drive system. This makes the structure of the heat exchanger entirely tied together, which benefits strength and rigidity while also providing reduced weight by eliminating components that are otherwise required. By housing the fan drive inside the plenum of the heat exchanger, some embodiments were able to achieve a 20% reduction in structure weight and a 45% reduction in drive weight compared to prior art heat exchangers with similar cooling capacity.
While the preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention.
Patent Grant
11781563
