Patent Application
20080110041
This invention generally relates to clothes dryers and, more particularly, to methods of drying goods using a clothes dryer.
With increasing energy costs, consumers are becoming more and more energy conscious. As such, consumers are demanding more energy efficiency from their appliances and the homes in which they live. Many appliance manufacturers have responded by attempting to increase their products' energy efficiency. However, no matter how efficient some appliances are made, the use of the appliance may be inefficient by causing other less efficient devices to also activate.
One such example is the use of a dryer for drying moist articles or goods, commonly referred to as a clothes dryer. Common practice with clothes dryers is to intake air from the room in which the clothes dryer is operating, heat it, pass it through the moist goods housed in a drying chamber, also referred to as a drum, and then exhaust it from the clothes dryer through an exhaust duct to the exterior of the building. During this process, it is common for as much as 150 cubic feet of air to be exhausted from the interior of the building to the exterior of the building per minute of operation. With typical drying cycles lasting approximately 45 minutes in length, the average clothes dryer can consume, on average, 6,750 cubic feet of air during a single cycle. This is the equivalent volume of air in seven rooms having eight foot ceilings and ten foot by twelve foot dimensions. As the air from the interior of the building is exhausted to the exterior of the building, the air that previously occupied the building is replaced by unconditioned air from the exterior of the building. Typically, this replacement air enters the building through doors, windows, cracks and other air passages fluidly communicating the interior of the building with the exterior.
This replacement of such a substantial volume of conditioned air from within the building with unconditioned air from the exterior of the building typically causes the condition of the air within the building to change. This, in turn, causes the heating, ventilating, and air conditioning system (HVAC system) of the building to activate to return the interior of the building to a pleasing condition. Unfortunately, the HVAC system is the most costly system in most buildings to operate. Thus, even if the individual operation of the clothes dryer can be made more efficient, the use of the clothes dryer causes the HVAC system to activate, reducing the overall efficiency of the clothes drying process.
Other problems exist with current clothes dryers. For example, the exhaust duct that vents the exhaust air from the clothes dryer to the exterior of the building can become plugged with lint or other particulate and catch fire causing structural damage to the building. Further, the exhaust pipes themselves can become extremely hot as a result of the hot exhaust air flowing through the pipes which can damage walls, wires, and other structure of the building that are positioned proximate the exhaust ducts. In addition, as the clothes dryer expels the humid warmed air from the building, the humid warm air takes with it a large quantity of heat energy that has been produced by the dryer to dry the clothes. This heat energy stored in the exhausted humid warm air is merely dumped into the exterior environment and wasted further reducing the overall operating efficiency.
Thus, there is a need in the art for a method of drying moist goods that reduces the amount of conditioned air that is expelled from the interior of the building during operation of the dryer, increases safety, and more efficiently utilizes the heat energy that is produced to dry the moist goods.
In view of the above, the present method provides a new and improved more energy efficient method for drying moist goods. In one aspect the method uses drying air drawn from an air supply exterior of the building, reducing the amount of conditioned air used during the drying process. As such, it is an aspect of a method according to the present invention that the overall energy efficiency of the building is increased as energy used to condition air internal to the building is not wasted by exhausting the air out of the building during the drying process.
In another aspect, the method may include a step of transferring heat energy between the exhausted air and the supplied air thereby reducing the amount of energy required during the drying process. As such, an aspect of one method according to the present invention is to draw air into the dryer proximate air being exhausted from the building.
In another aspect of a method, the method provides a method for drying moist materials with a dryer positioned within a room of a building. The method includes drawing air into the room housing the dryer and exhausting air from the building using a dual flow duct. The method includes the steps of drawing air into the room of the dryer through one passage of the dual flow duct, passing the air through the moist articles, and exhausting air out of the room through another passage of the dual flow duct.
In another aspect, a method according to the present invention includes sensing characteristics of the air flowing through the dryer, the air being drawn into or exhausted from the building or the air surrounding the dryer. The sensed characteristics can include temperature of the air, flow rate of the air, or air quality.
Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
Turning now to the figures,
The dryer 10 functions to dry moist goods 19 such as clothing, towels, rags, and the like placed within the dryer 10 by passing air through and/or across the material of the moist goods 19. As such, the dryer 10 includes a blower 22, shown schematically, that forces air through the dryer 10 and in contact with the moist goods 19. More particularly, in an embodiment, the blower 22 draws air through an air flow passage ducted through the dryer 10 that directs air through the moist goods 19 to be dried.
One portion of the air flow passage includes a drying chamber 26 in which the moist goods 19 are placed during the drying cycle. In the illustrated embodiment, the drying chamber, indicated generally by reference numeral 26, is provided by a drum 28 that is rotatably supported within the outer housing 30 of the dryer 10. The drum 28 rotates during the drying cycle causing the moist goods 19 that are located therein to tumble while drying. The tumbling action beneficially allows individual pieces of the moist goods 19 to separate facilitating the passage of drying air through and across the moist goods 19 to increase the evaporating action of the drying air, thereby increasing the rate of moisture removal from the moist goods 19. The drum 28 is typically rotatably supported by a plurality of rollers 31 and is rotatably driven by a belt 32 connected to and powered by an electric motor (not shown). In an embodiment, the electric motor that drives the drum 28 also drives the blower 22.
In an embodiment, the dryer 10 includes a heater, shown in a simplified manner at reference number 34. The heater 34 is positioned within the air flow passage passing through the dryer 10 upstream from the drum 28. The heater 34 heats the air prior to the air passing through the drum 28 and, consequently, prior to the air passing through the moist goods 19. Warm air can retain and absorb more moisture from the moist goods 19 and thereby reduce the amount of air and the length of time required to dry the moist goods 19. The heater 34 may be any practicable heater and may include such heaters as electrically resistive heaters, gas fired heaters, and the like.
In an embodiment, the blower 22 draws the “drying” air, indicated by arrows 40, into the dryer 10 directly from the exterior 16 of the building 17. The drying air 40 is then heated and passed through the moist good 19 to dry the moist goods 19. This configuration of using exterior air as the drying air 40 rather than conditioned air from within the interior 18 of the building 17 reduces the amount of energy used thereby increasing the overall energy efficiency of the process. Particularly, this configuration reduces the amount of conditioned air that is consumed by the dryer and expelled from the building 17. This, in turn, reduces the amount of non-conditioned air that enters the building from the outside, which, in turn, reduces the load on the HVAC system (not shown) to maintain the desired temperature and humidity levels of the building 17. As such, a method of drying moist goods 19 using a dryer 10 and dual flow duct 14 disclosed herein by drawing air from the exterior 16 of the building 17 through the dual flow duct 14 rather than drawing air from the interior of the building is highly beneficial.
Further, this configuration reduces the amount of energy that is wasted during warm periods by exhausting air that previously had been conditioned which required energy to cool the air. As noted previously, the HVAC system of a building is one of the most costly systems in a building to operate. Any reduction in unnecessary operation of the HVAC system will beneficially increase overall efficiency and energy consumption of the building as a whole.
As the drying air 40 passes through the drying chamber 26 and the moist goods 19, the previous lower humidity drying air 40 absorbs moisture from the moist goods 19 and becomes humid stale exhaust air, indicated by arrows 44 and proceeds to be exhausted from the dryer 10. The exhaust air 44 passes through an exhaust air portion of the air passage of the dryer 10 downstream from the drying chamber 26 to the dual flow duct 14. The dual flow duct 14, in part, fluidly communicates the exhaust portion of air passage with the exterior 16 of the building 17 and as such allows the exhaust air 44 to be exhausted from the dryer 10 to the exterior 16 of the building 17.
More particularly, in an embodiment, a first end 50 of the dual flow duct 14 connects to an air intake and exhaust manifold 52 of the dryer 10, and the second, opposite, end 54 of the dual flow duct is positioned in and in fluid communication with the exterior 16 of the building 17. In an embodiment, the second end 54 of the dual flow duct 14 is connected to a second air intake and exhaust manifold 43 positioned outside of the building 17. As is illustrated, the second air intake and exhaust manifold 43 is configured to prevent rain or other debris from entering the dual flow duct 14. This can be accomplished by including canted roughs, tops or covers over the openings through which drying air 40 and exhaust air 44 enter and exit, respectively, the second air intake and exhaust manifold 43. Additionally, the openings in the second air intake and exhaust manifold may include grates, grills, mesh and the like to prevent debris from entering the openings.
The dual flow duct 14 includes two air flow passages including an air supply passage 60 for drawing in the drying air 40 and an air exhaust passage 62 for exhausting the exhaust air 44. In an embodiment, the air supply passage 60 and air exhaust passage 62 are positioned proximate one another such that the two air flow passages are separated by a common wall 66. As such, the air supply passage 60 and the air exhaust passage 62 are formed in a common structure, namely dual flow duct 14. As such, the air that is drawn in through the air supply passage 60 and the air exhausted through the air exhaust passage 62 flow in the common air flow structure, dual flow duct 14.
In an embodiment, as illustrated in
In an embodiment, the common wall 66 is made from a thermally conductive material such as metal. Using a common wall 66 of a thermally conductive material beneficially increases the efficiency of the dryer 10. In such a configuration, some of the heat energy stored by the exhaust air 44 passing through the air exhaust passage 62 is dissipated to the drying air 40 drawn in through the air supply passage 60 through the thermally conductive common wall 66. The transfer of heat energy from the exhaust air 40 to the drying air 44 reduces the amount of heat energy required to be added to the drying air 44 by the heater 34.
As it is beneficial to have as much heat energy transferred from the exhaust air 44 to the drying air 40 as possible, an embodiment of the present invention includes heat transfer structures, such as heat pipes and/or, as illustrated, heat transfer fins 74 that extend from the outer and inner surface 70, 71 of the common wall 66 of the dual flow duct 14. The heat transfer fins 74 increase the amount of surface area for the air flowing through the air intake and air exhaust passages 60, 62 to contact and impinge further increasing the amount of heat that will be dissipated from the exhausted air 44 and will be absorbed by the drying air 40. Further, the heat transfer fins 74 may be used to mount, position and/or support the common wall 66 within the outer annular wall 68. In such an embodiment, the heat transfer fins 74 extend entirely from the outer surface 70 of the common wall 66 to the inner surface 69 of the outer annular wall 68.
Condensation may occur as the warm humid exhaust air 44 reduces in temperature as it dissipates heat energy to the drying air 44. Therefore, in an embodiment, the outer annular wall 68 and inner common wall 66 are preferably made from a stainless or corrosion resistant material to prevent any condensation that forms thereon from damaging the walls 66, 68, which may include metal or plastic.
The concentric configuration, having the air exhaust passage 62 passing through the air supply passage 60, has several beneficial features. First, as noted previously, the dual flow duct 14 functions as a dual flow heat exchanger. With the air exhaust passage 62 positioned within the air supply passage 60, the entire surface area of the common wall 66 that surrounds the air exhaust passage 62 is in thermal communication with the exhaust air 44 and drying air 40 on opposite sides of the common wall 66. Thus, any heat energy that is dissipated from the exhaust air 44 will be transferred to the drying air 40. It should be noted that the illustrated embodiment uses walls 66, 68 having round cross-sections, one of skill in the art will recognize that the walls 66, 68 are not so limited in shape and can be any shape such as square, rectangular, oval, and the like. Furthermore, as the outer annular wall 68 and common wall 66 are both have the same shape, it is not required that both walls have the same shape. For example and as illustrated in an alternative embodiment of a dual flow duct 414 in
As the wall forming the air exhaust passage can become very hot, it is a benefit of the configuration illustrated in
As indicated previously, the dryer 10 includes an air intake and exhaust manifold 52 for connecting the dual flow duct 14 to the dryer 10. As best illustrated with reference to
In an embodiment, the duct connection end 81 of the air intake and exhaust manifold 52 is configured of easy attachment to the dual flow duct 14. In an embodiment and as illustrated in
Preferably, the flanges are configured to minimize resistance on the fresh air 40 flowing through the air supply passage 60 as it passes from the dual flow duct 14 to the air intake and exhaust manifold 52 as well as the exhaust air 44 flowing from the air intake and exhaust manifold 52 to the dual flow duct 14 through the air exhaust passage 62. To minimize the air resistance and as illustrated in
The dryer 10 may further include sensors 90 for sensing characteristics of the drying air 40 and exhaust air 44 flowing through the dryer 10 as well as the air supply and air exhaust passages 60, 62. These sensors 90 can sense characteristics such as air temperature, flow rate, presence of hazardous gases, humidity and the like. The sensors 90 can operably communicate with a controller 92 or other logic device for operably controlling the dryer 10 in response to the sensed characteristics. Particularly, the sensed condition of the air can be compared with predetermined or user determined values. Air temperature and flow rate sensors can be beneficial in helping determine if any portions of the air flow passages are plugged or if the dryer 10 is functioning properly. In such a case, the dryer 10 and its controller 92 may be configured to activate an alarm (not shown) or cease operation until the dryer 10 or dual flow duct 14 has been inspected and cleared.
With reference to
Although existing ductwork in buildings does not have dual passages for providing an air supply passage and an air exhaust passage, existing structure can be retro fit to form embodiments of dual flow duct work. Rather than removing the existing ductwork and replacing it with new dual flow ducts, existing ducts can be used along with a second duct pipe that is installed in the structure in addition to the existing ductwork. After the new duct pipe is installed in the dwelling, the combination of old and new ducts can function as explained previously, i.e. the old duct will continue to be used to exhaust the dryer, while the new duct will supply outside air to the dryer.
In a further embodiment of the present invention illustrated in
As explained previously, standard dryers draw drying air directly from the ambient air within the room housing the dryer and then exhaust it to the exterior of the building. The ambient air directly surrounding the dryer is then replenished with other conditioned air from within the building. Typically, this air enters through the door or gaps around the door leading to the room. The exhaust air exiting the building is replaced by other air from within the building that enters the building through doors or windows. As such, conditioned air is used and exhausted from the building during the drying cycle. However, with the present embodiment, the dryer 210 draws drying air from the room in which it is located, but the air is not replaced by conditioned air from the interior 18 of the building 17, but the ambient air surrounding the dryer is replaced by unconditioned air from the exterior 16 of the building 17.
In this embodiment, the dual flow duct 14 includes both an air supply passage 60 and an air exhaust passage 62 and an air intake and exhaust manifold 252 connected to the dual flow duct 14 external to the dryer 210. The air intake and exhaust manifold 252 includes an exhaust air inlet 263 that is interconnected to dryer's exhaust air outlet 164. As such, exhaust air 244 exhausted from the dryer 210 is exhausted through the air intake and exhaust manifold 252 and then the air exhaust passage 62 of the dual flow duct 14, similar to the process as explained previously.
However, the dryer 210 draws the drying air, indicated generally by arrows 240 directly from the ambient air within the interior 18 of the building 17, and more particularly, the room housing the dryer 210. However, the ambient air within the room is not primarily replenished by conditioned air from the rest of the building 17. In this embodiment, the air intake and exhaust manifold 252 includes a drying air outlet 265 that is in fluid communication with the exterior 16 of the building 17 through the air supply passage 60. As such, when the dryer 210 draws drying air 240 from the room for drying the moist goods 19, the air is replaced by air, indicated generally by arrows 241, that is drawn into the building 17 through the duct 14 via a vacuum created by the exhaust air 244 exiting the building 17.
This embodiment can be extremely beneficial as the conditioned air from the rest of the building is not used to continue the drying process. Instead, unconditioned air 241 from the exterior 16 of the building 17 is used. To prevent conditioned air from escaping the building 17 when the dryer 210 is inoperative, the air intake and exhaust manifold 252 includes a damper 267 that can close the drying air outlet 265 of the air intake and exhaust manifold 252 and prevent fluid communication between the interior 18 and exterior 16 of the building 17 via the air supply passage 60 of the dual flow duct 14. The damper 267 may be configured for manual or automatic opening or closing. As such, the damper 267 may be configured to be opened or closed directly by the user or configured to open or close automatically upon activation or deactivation of the dryer 210.
In another embodiment, illustrated in
It will be recognized by one of ordinary skill in the art that the embodiments of the ducts disclosed previously could be practiced using plastic or other non-thermally conductive material rather than thermally conductive material. However, such configurations will not have the additional benefits of functioning as a heat exchanger. The use of plastic duct could be extremely beneficial when retrofitting existing duct with a second passage by using flexible plastic duct that can be more easily inserted through the existing ductwork.
All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
