Patent Application
20130224043
The present invention generally relates to air mixing devices, and more particularly to an air mixing device suitable for use in open buildings spaces.
Air mixing devices such as fans are useful in larger open commercial and industrial building spaces for a variety of reasons. These air mixing devices may be used for recirculating air within the open space defined by the building superstructure (e.g. walls, floor, and ceiling) to provide proper ventilation and reduce vertical temperature stratification of air within the space. This destratifying effect helps maintain a uniform temperature within the structure for optimum comfort of the building occupants and heating/cooling efficiency by circulating warm air which rises and typically occupies the upper elevations with cooler air which sinks and typically occupies the lower elevations within the open space.
In addition to temperature regulation, air mixing devices also serve an additional useful purpose when the building structure serves as a commercial breeding and rearing facility for animals which occupy the space. In the case of a poultry house, for example, levels of ammonia generated by decaying manure may be higher near the floor than at higher elevations within the building structure. To promote healthy air quality within the confined environment and meet the ventilation requirements of the animals, it is further useful therefore to reduce air stratification within such spaces by creating an air circulation pattern which vertically mixes the air for purposes of maintaining uniform air quality throughout the facility.
To further promote good air quality, some air mixing devices may draw fresh replacement outside air into the building. During colder months, air mixing devices may sometimes incorporate heat exchanger elements (e.g. electric resistance, steam, or hot water coils) to heat the outside air prior to discharge into to the open building space. This air tempering approach alone, however, increases energy consumption and operating costs. In addition, the heated hot air may be discharged from the air mixing devices at significantly higher temperature than the room air inside the building and at high velocity which may cause uncomfortable drafts and temperature fluctuations at various locations within the facility.
An air mixing device and system is desired for improved air mixing, distribution, and energy efficiency.
An air mixing device or unit is provided that is operable to mix and temper fresh outside air with warmer room air prior to discharging the mixed air to open spaces within a building. The air mixing unit further creates an air circulation pattern that is intended to destratify air within the space to promote uniform temperatures and air quality. The buildings may be any type of building structure such as commercial and industrial facilities having human and/or animal occupants, including animal rearing structures such as without limitation poultry houses. The air mixing unit is readily adaptable to private and public spaces such as without limitation warehouses, factories, auditoriums, and other venues having relatively larger open spaces that require ventilation and heating.
In one embodiment according to the present disclosure, an air mixing unit for a building includes a frame configured for mounted to a building superstructure and a centrifugal fan supported by the frame for rotational movement. The fan includes a rotatable body, a drive shaft defining a vertical rotational axis, a plurality of radial blades extending in a horizontal direction outwards from the fan axis, a top air inlet, and a bottom air inlet. The air mixing unit further includes a motor drive operable to rotate to the fan. Rotation of the fan draws inlet air through both the top and bottom air inlets, mixes the inlet air together, and radially discharges the mixed air laterally outwards from the fan. In some embodiments, the top and bottom air inlets are axially aligned with the vertical rotational axis of the fan to draw air into the fan from opposing axial directions. In further embodiments, the top air inlet may be defined by at least one opening in a circular shaped upper plate and the bottom air inlet may be defined by at least one opening in a circular shaped lower plate spaced vertically apart from the upper plate.
In one embodiment according to the present disclosure, an air mixing system includes a building having a floor, a ceiling, and vertical walls defining an open space, and an air mixing unit disposed in the open space of the building. The air mixing unit includes a rotatable centrifugal fan having horizontally-oriented radial vanes, axially aligned top and bottom air inlets, a vertically-oriented fan drive shaft operable to rotate the fan and defining a vertical rotational axis of the fan, and a lateral discharge outlet. The system further includes a motor drive operable to rotate to the fan. Rotation of the fan draws an air inlet stream into the fan from opposing axial directions through the bottom and top air inlets, mixes the air inlet streams for tempering the air, and radially discharges the mixed air laterally outwards from the fan to the open space. In some embodiments, the discharge outlet extends for 360 degrees around the rotational axis of the fan. In further embodiments, the fan may be mounted proximate to the ceiling of the building.
In one embodiment according to the present disclosure, a method for mixing and destratifying air within an open space of a building is provided. The method includes: mounting a centrifugal fan in the open space, the fan including a rotatable fan body comprised of vertically spaced apart upper and lower plates each having at least one air inlet opening formed therein, and a plurality of radial blades mounted between the plates, the fan further including a vertically oriented central drive shaft operable to rotate the fan and defining a rotational axis of the fan; rotating the drive shaft with a motor drive; drawing inlet air streams into the fan from opposing axial directions through the air inlet openings in the upper and lower plates; mixing the inlet air streams; and radially discharging the mixed inlet air streams laterally outwards into the open space. In some embodiments, the air inlet openings are concentrically aligned with the rotational axis of the fan. In some embodiments, the fan includes a lateral air discharge outlet that extends for a full 360 degrees around the fan.
The features of the preferred embodiments will be described with reference to the following drawings where like elements are labeled similarly, and in which:
All drawings are schematic and are not drawn to scale.
This description of illustrative embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description of embodiments disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “attached,” “affixed,” “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “adjacent” as used herein to describe the relationship between structures/components includes both direct contact between the respective structures/components referenced and the presence of other intervening structures/components between respective structures/components. Moreover, the features and benefits of the invention are illustrated by reference to the preferred embodiments. Accordingly, the invention expressly should not be limited to such preferred embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto.
Fan 30 may be a dual air inlet device in some embodiments configured to draw air from two different axial directions, as shown in
Fan 30 includes two axial and opposing air inlets including an upper/top air inlet 36 and lower/bottom air inlet 38 through which air is drawn into the fan. Top air inlet 36 is defined by upper plate 40 which includes a centrally located main air inlet opening 42 and a plurality of auxiliary air inlet openings 44 spaced around opening 42; air inlet openings 42 and 44 collectively defining a first air inlet such as upper air inlet 36. Main air inlet opening 42 may be circular shaped as shown and arranged concentrically with respect to a rotatable central fan drive shaft defining a vertical rotational axis RA for fan 30. Auxiliary air inlet openings 44 may be arcuately shaped in some embodiments and arranged circumferentially spaced apart proximate to main air inlet opening and concentrically aligned with rotational axis of the fan. The auxiliary air inlet openings 44 increase the air intake flow into the fan and are also provided for structural reasons such as avoiding a single very large central air inlet opening which may weaken the fan structure.
Configured similarly to upper plate 40 in some embodiments, bottom air inlet 36 is defined by lower plate 50 which may include a centrally located main air inlet opening 52 and a plurality of auxiliary air inlet openings 54 spaced around opening 52; air inlet openings 52 and 54 collectively defining a second air inlet such as lower air inlet 38. In other embodiments, the air inlets in the upper and lower plates 40, 50 may be configured differently and/or vary in size to alter the square inches of open area thereby being useful for increasing or decreasing the quantity of air drawn into fan 30 through either the upper or lower air inlets 36, 38. This allows one skilled in the art to regulate the amount of already warmed room air that is mixed in fan 30 with cooler outside air to balance the air tempering. It will be appreciated, therefore, that the size and/or configuration of the air inlet openings may be varied and do not limit the invention.
A plurality of radial blades 70 are provided and arranged around rotational axis RA of the fan and rotatable central drive shaft 80. Blades 70 extend radially and laterally outwards from rotational axis RA and are circumferentially spaced apart by an angular distance as shown in
With continuing reference to
With continuing reference to
Drive shaft 80 is configured and dimensioned to be insertably received through tubular hub 90 as shown in
A mixing chamber 31 (see
Referring to
It will be appreciated that mounting frame 60 may have other suitable configurations so long as the fan 30 may be supported by the frame and in turn the building superstructure.
With continuing reference to
In some embodiments, fan 30 (i.e. upper and lower plates 40, 50) may protrude laterally outwards beyond frame 60 as shown in
Referring to
In other possible embodiments, motor drive 100 may be a direct drive system (not shown) wherein the motor 102 is directly coupled to fan drive shaft 80. In addition, a variable speed motor may be provided for either belt or direct drive options to vary the air delivery from fan 30. The invention is therefore not limited to any particular type drive system or motor so long as the motor is operable to rotate the drive shaft 80 and fan 30 coupled thereto.
Fan 30 may be formed of any suitably strong material having an appropriate thickness for the intended application. In some possible embodiments, upper and lower plates 40, 50 and fan blades 70 may be made of metal, reinforced or unreinforced plastics, fiberglass, graphite composite materials, or others. In some preferred embodiments, the plates and fan blades may be made of aluminum or galvanized steel of sufficient gauge so that fan 30 is structurally self-supporting. In one embodiment, 16 gauge galvanized steel plate may be used for the plates 40, 50 and blades 70.
Mounting frame 60 may be formed of any suitably strong material having an appropriate thickness for the intended application to support the weight of fan 30, motor drive 100, and related appurtenances. In some possible embodiments, the frame may be constructed of metal, reinforced or unreinforced plastics, fiberglass, graphite composite materials, or others. In some preferred embodiments, the frame 60 may be made of square tubes comprised of aluminum or galvanized steel of sufficient gauge. In one embodiment, 11 gauge square galvanized steel tubes may be used for horizontal and vertical members 62, 64.
Fan 30 may be of any suitable size for the intended application. In one representative embodiment for purposes of illustration only, without limitation, fan 30 may have a diameter of about 72 inches (i.e. diameter of circular upper and lower plates 40, 50) and height of approximately 10 inches (i.e. approximately height of radial blades 70). Any suitably sized fan 30 may be provided depending on the volumetric air flow capacity (e.g. CFM) needed for the intended application. It will be appreciated that in addition to the physical size of fan 30 provided, the speed of the motor drive 100, number of blades 70 and their configuration, and other factors will determine the air flow capacity of the fan 30. It is well within the ambit of one skilled in the art to modify these parameters as needed for a given fan installation. As a non-limiting example, for the exemplary dimensioned embodiment given above, fan 30 may have a volumetric flow capacity of about 30,000 CFM.
An open attic 11 may be defined between ceiling 14 and roof 12. Fresh air may be drawn into the attic 11 through the gable ends and/or from under the eaves of building 10 (see
In some embodiments (not shown), building 10 may have a partially or totally open ceiling area lacking a physical ceiling structure in some or a majority of areas beneath the joists and rafters (not shown) supporting the roof 12 (e.g. open joist design). Air mixing units 20 may be used for air circulation and ventilation in these open joist types of structures in addition to building 10 shown in
Air mixing units 20 may be mounted at or proximate ceiling 14 as shown in
With continuing reference to
Air intake ducts 110 may terminate at a lowest point that is at or proximate to the ceiling 14, and preferably further terminates at a point that is vertically spaced apart from fan 30 as shown in
In operation, rotation of the fan 30 with radial blades 70 by motor drive 100 draws air axially into the body 32 of the fan through both opposing upper and lower air inlets 36, 38 which are axially aligned with rotational axis RA of the fan in some embodiments. Cooler outside air (pre-warmed or not in attic 11) is drawn into fan 30 through top air inlet 36 and mixed in mixing chamber 31 with and tempered by warmer rising room air drawn in through bottom air inlet 38 before any air is radially/laterally discharged by the fan to the temperature controlled conditioned room space (see airflow directional arrows in
Beneficially, air mixing system disclosed herein does not require any heating of air within the air mixing unit itself and takes full advantage of existing warmer room temperature air to temper the incoming cooler air. In addition, the lateral dispersion of air from the fan 30 in all directions while avoiding an axial downward discharge directly toward the building occupants advantageously provides a gentle flow of air and ventilation thereby avoiding uncomfortable localized drafts. Preferably, the fans 30 in some embodiment may be characterized by relatively low velocity air discharge over a wide area to minimize drafts.
The foregoing air mixing system provides more uniform air temperatures throughout the building because it immediately mixes cooler outside air upon entry with warmest inside air that has risen to the ceiling area and distributes the tempered air throughout the building. Gentle, but consistent air movement through the building or facility without cold drafts ensures adequate fresh air to building occupants such as animals in some embodiments and promotes drying of manure in addition to dispersion of localized ammonia concentrations (if any) through air destratification.
In some embodiments, referring to
While the foregoing description and drawings represent exemplary embodiments of the present disclosure, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope and range of equivalents of the accompanying claims. In particular, it will be clear to those skilled in the art that embodiments according to the present disclosure may be include other forms, structures, arrangements, proportions, sizes, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. One skilled in the art will further appreciate that the embodiments may be used with many modifications of structure, arrangement, proportions, sizes, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. In addition, numerous variations in the exemplary methods and processes described herein may be made without departing from the spirit of the present disclosure. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims and equivalents thereof, and not limited to the foregoing description or embodiments.
