Clothes dryer

A clothes dryer is provided, the dryer comprising a drum, an intermediate air channel, a lint compartment, a lint collector, an outlet pipe, a moisture trap and pump, a heating element, and a fan, these several components being coupled together and defining a closed loop wherein air flows through the loop in response to operation of the fan. Upon operation of the dryer, the fan begins to force air through the closed loop and the heating element heats the air to within a predetermined temperature range at which point the heating element turns off and the dryer operates to dry the clothes by recycling the heated air through the closed loop over and over again until the clothes within the dryer are dry. Should the air temperature within the loop fall below the predetermined range, the heating element can intermittently activate to heat the air back to within the range.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to clothes dryers, and in particular to an energy-efficient clothes dryer.

2. State of the Art

A clothes dryer is a useful household appliance that is useful in removing moisture from clothing and other textiles usually after the clothing has been washed in water.

A traditional clothes dryer operates by continuously pulling in cool, dry, ambient-air surrounding the dryer and heating it before passing it through the tumbler where the clothes are located. As the heated air passes over the wet clothing, the moisture within the clothing evaporates into the heated air, thus drying the clothes. The resulting hot, humid air is vented back out into the ambient air, usually to the ambient air outside the home or dwelling in which the dryer is operating, to allow the dryer to continue to pull the cool, dry inside air over the heating element to continue the drying process.

Because the traditional dryer must continuously raise the temperature of the ambient air entering the dryer to a higher temperature to operate effectively, it must necessarily consume a substantial amount of energy to do so. This is inherently inefficient. Also, traditional dryers provide a constant air flow through the dryer to dry the clothes and fail to adjust the air flow based on the individual load within the dryer, which wastes the power supplied to the motor and heating element.

In view of the above, and in view of the movement toward “greener” appliances, there is a need for a clothes dryer that addresses the above-mentioned problems to operate more efficiently and cost-effectively.

DISCLOSURE OF THE INVENTION

The present invention relates to clothes dryers, and in particular to an energy-efficient clothes dryer.

An aspect of the present invention includes a dryer comprising a drum, an intermediate air channel, a lint compartment, a lint collector, an outlet pipe, a moisture trap and pump, a heating element, and a fan, these several components being coupled together and defining a closed loop wherein air flows through the closed loop in response to operation of the fan. Upon operation of the dryer, the fan begins to force air through the closed loop and the heating element heats the air to within a predetermined temperature range at which point the heating element turns off and the dryer operates to dry the clothes by recycling the heated air through the closed loop over and over again until the clothes within the dryer are dry. Should the air temperature within the closed loop fall below the predetermined range, the heating element can activate to heat the air back to within the range.

Another aspect of the present invention includes the lint collector within the lint compartment that functions as both a lint filter and a steam condenser as the moist hot air exiting the drum of the dryer flows through the lint collector. The lint compartment, in conjunction with the lint collector, not only retains the lint that flows out of the drum, but also collects the moist air to the point that water droplets form within the lint compartment and subsequently fall onto a lower surface of the lint compartment and are channeled toward the outlet pipe that guides the water droplets to the moisture trap that collects the water. The collected water is then removed from the closed loop by the operation of the pump. By removing at least some of the moisture from the air within the closed loop, the dryer is able to retain the heat of the air and continue to pull moisture out of the load of clothing to be dried.

Another aspect of the present invention includes steam drying the load of clothing. Steam drying the clothing allows kills of bacteria and also extracts less lint from the clothing within the dryer. Whereas traditional clothes dryers cause clothing to excessively shed lint, drying the load of clothing by steam does not.

Another aspect of the present invention includes an air flow sensor within the closed loop that measures the flow of air. Based on the measurement, the fan speed can be adjusted. For example, for light loads, for loads with little lint, or for relatively dry loads, the fan does not have to work as hard to maintain the requisite air flow through the closed loop to properly dry the clothes. As a result, the fan speed can be reduced, thus diminishing the consumption of energy to power the fan. On the other hand, where the load in the drum is large or substantially wet, the fan may adjust its power consumption to adjust its rotational speed to maintain the requisite air flow through the closed loop. In this way, the dryer of the present invention supplies the appropriate power to the fan when it is needed, but also conserves power to the fan when it is not needed.

Another aspect of the present invention includes a scented bag that functions as the lint collector, the scented bag being replaceable as needed.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

As discussed above, embodiments of the present invention relate to clothes dryers, and in particular to an energy-efficient clothes dryer.

As shown inFIG. 1, the clothes dryer10comprises a drum14having an air inlet12, the drum14being capable of holding and rotating a load of laundry, typically clothing. When a load of clothing is added to the drum14, the door to the drum14is closed and the dryer10can be activated. By closing the door to the drum14, a closed loop within the dryer10is air-tightly sealed and the dryer10can begin its intended operation. Once activated, the drum14begins to rotate to agitate the clothing therein. A fan32, to be discussed in further detail below, begins to force air within the individual components of the closed loop through the dryer10. Parts of the closed loop include, but are not limited to, the drum14, a lint compartment18, an outlet pipe28, and the fan32. Air within the closed loop, shown by arrows inFIG. 1, is introduced into the drum14by way of the air inlet12, and the air circulates within the drum14in and around the clothing. The air serves to dry the clothes until the clothes are dry and/or the dryer10finishes its programmed cycle.

Adjacent to the drum14is intermediate air channel16, which couples the interior air space of the drum14to the lint compartment18, to be discussed in further detail below. After the air passes through the clothing in the interior of the drum14, the air is drawn into the intermediate air channel16and subsequently into the lint compartment18. Between the drum14and the intermediate air channel16is positioned filter17. Filter17consists of a semi-permeable barrier made of connected strands of metal, fiber, or other flexible/ductile material. Filter17is similar to a web or net in that it has many attached or woven strands that are close enough to one another to prevent articles of clothing or other smaller-sized particles (i.e., buttons, coins) from entering into the intermediate air channel16. However, the strands in filter17are far enough apart to allow the air within the drum14to freely flow through the strands without noticeable restriction or reduced air flow speed.

As shown inFIG. 2, the intermediate air channel16further includes an exit pipe21and an air flow sensor24in the exit pipe21. Exit pipe21is a section of the intermediate air channel16on which a lint collector22, to be discussed below, is coupled to the intermediate air channel16. The air flow sensor24is an air flow meter that measures the actual speed of the air flowing through the intermediate air channel16in a defined time segment. The air flow sensor24works in conjunction with the fan32, again, to be discussed in detail below. Additional air flow sensors24may be placed in locations along the closed loop of the dryer10, including along the outlet pipe28, to be described in detail below.

As shown inFIG. 2, the lint compartment18further comprises a lint compartment cover20, the lint collector22, mentioned above, that is housed within the lint compartment18, and an angled lower surface23. The lint compartment18, as shown, is a rounded shape having a rounded upper and lower surface to assist in shedding moisture collected in the compartment18. The lint compartment18is of sufficient size to house the lint collector22. However, the lint compartment18can be of any shape sufficient to house the lint collector22therein and provide the proper moisture-shedding properties. The cover20can be detached from the lint compartment18so that the lint collector22can be replaced or cleaned as necessary. It is contemplated that the lint collector22is reusable. However, in the alternative, and if desired, the lint collector22can be used once, disposed of, and replaced. The cover20is positioned in the dryer10in such a position that the user can easily reach the cover20to detach it from the lint compartment18. Then, after cleaning and/or replacing the lint collector22, the cover20is reattached to the lint compartment18. The seal between the lint compartment18and the cover20is airtight, or substantially airtight, to prevent air from seeping out of the lint compartment18that might reduce air flow speed. The cover20is dome-shaped, the practical application of the dome-shape will be explained below.

The lint collector22has an opening in the top portion thereof. The opening can be slid over, or coupled to, the exit pipe21to air-tightly seal the collector22onto the exit pipe21. The seal between the exit pipe21and the lint collector22is strong enough to resist the force of the air flow pushing against the interior surface of the lint collector22as air enters the lint collector22, fills the space within the lint collector22, and exits the lint collector22through the lining of the lint collector22, as shown by the arrows inFIG. 2. The opening in the lint collector22may be adjustable and adjusted to cinch the exit pipe21to create the seal. Or, in the alternative, the opening in the lint collector22may be fixed and stretched to cinch around the exit pipe21to create the seal.

Although the lint collector22is shown as a bag-type filter in the embodiment shown inFIG. 2, the lint collector22can be any type of filter that functions both as a lint filter and a steam condenser. As the air moves across and around the clothing within the drum14, the air evaporates the moisture in the clothing and carries the moisture away from the clothing and into the intermediate air channel16, past the air flow sensor24, and into the lint collector22housed within the lint compartment18. The moving air within the drum14also picks up small detached fibrous portions of threading in the clothing (i.e., lint) and moves them with the moist air into the lint collector22. The lint collector22collects the lint out of the moving air by retaining the lint within the walls of the lint collector22while allowing the moving air to flow through the same walls. The lint collector22can be scented to emit a scent into the air flowing through the closed loop. By scenting the air flowing through the dryer10, the clothes within the dryer10can also acquire the fresh scent or aroma of the lint collector22. The lint collector22can be provided with any number of scents, from fruits to sweets and from perfumes to natural aromas. The scent on the lint collector22can be of varying strengths from faint to powerful. They can also be manufactured to have varying durations of usage, from one-time use to extended multiple-cycle use, upwards of 18-24 loads.

The lint collector22also functions as a condenser to condense the steamed moist air flowing through the lint collector22. As the moist air and lint flow into the lint collector22, the moist air begins to cool and condense. Once the moist air condenses enough, the moisture in the air forms water droplets that fall from the lint collector22and drop onto the angled lower surface23of the lint compartment18. Also, because the cover20, that is positioned substantially over the lint collector22, is dome-shaped any moisture that condenses on the cover20runs down the dome and drips from the edges of the dome onto the angled lower surface23, thus avoiding dripping directly onto the lint collector22from above. Embodiments of the dryer10include the domed cover20being continuously exposed to the ambient air, thus allowing the cover20to remain relatively cool and provide a relatively cooler surface upon which the moisture laden air within the lint compartment18can condense and collect. Moreover, any moisture that condenses elsewhere in the lint compartment18, such as for example on the inner surfaces of the lint compartment18, may collect and then drain onto the angled lower surface23. Embodiments of the dryer10include one or more of the lint compartment18, the lint collector22, and the outlet pipe28being continuously exposed to the ambient air, whether physically positioned within or outside of the dryer10, to further reduce the cooling and moisture collecting capabilities of these components.

The angled lower surface23is angled downward from front to back with respect to the dryer10, which resultantly directs the water droplets that have dropped thereon to run from the point of contact with the angled lower surface23to the back of the lint compartment18. At the back of the lint compartment18, where the angled lower surface23ends, the lint compartment18couples to an opening26in the outlet pipe28. The lint compartment18, the angled lower surface23, and the outlet pipe28are structurally configured to allow the water droplets running down the angled lower surface23to enter the outlet pipe28at the opening26, as shown inFIG. 2. Moreover, the angled lower surface23may also be u-shaped to further assist the water droplets to accumulate at the bottom of the u-shape and transition toward the opening26in the outlet pipe28.

To allow the lint collector22to have condenser-like properties, the lint compartment18can be insulated from the drum14such that the heat from the drum14does not interact with the lint collector22to heat the lint collector22. Embodiments of the dryer10include the lint compartment18having an insulation layer provided under the bottom surface of the lint compartment18, between the lint compartment18and the drum14, to directly shield the bottom of the lint compartment18from the heat of the drum14. Placing the insulation layer only on the bottom of the lint compartment18also allows heat from within the lint compartment18to dissipate out of the remaining surfaces of the lint compartment18. Embodiments of the dryer10include the drum14having an insulation layer thereon to prohibit heat from the drum14interacting with the lint compartment18. Embodiments of the dryer10include both the lint compartment18and the drum14each having an insulation layer or barrier placed thereon to prohibit the heat transfer directly between the drum14and the lint compartment18. In these ways, the lint compartment18can remain relatively cool to provide condenser-like properties that allow the moisture-laden air within the lint compartment18to condense.

Moreover, if needed, outside ambient air can be channeled into the lint compartment18through an opening in the lint compartment18to further cool the lint compartment18to assist in condensing the moist air therein. Embodiments of the dryer include the lint compartment18having a fan positioned in an exterior surface of the lint compartment18to force relatively cool ambient air into the lint compartment. Such a fan would permit air to flow into the lint compartment18and prohibit the moisture-laden air from escaping thereby.

Further in addition, the lint collector22can have an interior surface and an exterior surface. The interior surface and the exterior surface may be comprised of differing fabrics or materials having differing moisture-related properties. For example, and not to limit the disclosure of the invention, the interior surface of the lint collector22can be a mesh-like filter to catch and retain the lint in the moist air while permitting the moisture to pass therethrough, whereas the exterior surface can be configured of materials or surface structure to encourage the moist air to attach, cool, and condense thereon. Once accumulated, the condensed water may drop onto the angled lower surface23therebelow. Embodiments of the dryer10may include the lint collector22being constructed of fabrics and materials that quickly and easily absorb and release moisture, such as, but not limited to, corduroy, silk, wool, or acrylic. Such fabrics could allow moisture to collect and over time accumulate to thereafter drop to the lower surface23. Embodiments of the lint collector22may include the lint collector22being constructed of fabrics and materials that do not easily or quickly absorb moisture, such as, but not limited to, nylon, acetate, or polyester. Such fabrics could allow moisture to collect and quickly drop to the lower surface23. Embodiments of the lint collector22may include the lint collector22being constructed of fabrics and materials that are especially efficient at collecting moisture in the air, such as, but not limited to, polypropylene or polyethylene. Such fabrics can be configured in the shape of nets. Such fabrics could allow the lint collector221omore efficiently collect the moisture in the air within the lint collector22and subsequently shed the collected moisture to the lower surface23. Embodiments of the lint collector22may include the lint collector22being made of multiple layers of the same material having different weave patterns or weave patterns that are similar but offset from layer to layer. The moisture can collect more efficiently between multiple layers.

Upon entering the outlet pipe28, the water droplets travel through the outlet pipe28by gravity to the moisture trap30located at a bottom portion of the pipe28and at a bottom portion of the dryer10, as shown inFIG. 3. Embodiments of the dyer10include the outlet pipe28also being insulated from the drum14, such that the heat within the drum14does not interact with the outlet pipe28and the outlet pipe28remains sufficiently cool to collect moisture within the closed loop. In this way, the outlet pipe28assists in the condensation of the moisture in the air flowing through the closed loop. As moist air flows down and through the outlet pipe28, the moisture in the air can adhere to the cooler walls of the outlet pipe28and additional water droplets form and the existing water droplets become larger.

Because the moisture trap30is located at the bottom portion of the outlet pipe28, the moisture flows by gravity into the moisture trap30and is retained therein. The water in the moisture trap30is then pumped out of the closed loop by a pump34. The pump34pumps the water out of the moisture trap30, through a water line38, and into a drain40associated with the washer, or other like water drain, to remove the moisture from the closed loop. As disclosed, the pump34is a magnetic drive pump, but the pump34may be of any type or variety that functions to remove the water from the moisture trap30and pumps it into the exterior drain40.

Along with the water droplets that flow through the outlet pipe28, the air that has exited from the lint collector22also flows into the outlet pipe28. The air enters the outlet pipe28at the opening26and flows through the outlet pipe28, over the moisture trap30, and into the fan32, mentioned above.

The fan32functions to force the air through the dryer10to achieve the intended operation. When actuated, the fan32drives the air, within the closed loop, up and through a heating element36, which heats the air to a desired upper temperature. The heated air thus enters the drum14through the air inlet12and the heated air begins to dry the clothing in the drum14. Because the air that passes through heating element36is heated, enters the drum14, and evaporates the moisture in the clothing within the drum14, the heated air provides the additional benefit that the heated steam kills bacteria and creates an environment that reduces the wrinkles in the load of clothing in the drum14as the clothing is dried.

The fan32drives the heated air within the drum14through the intermediate air channel16, through the lint compartment18and the lint collector22, through the outlet pipe28and back into the fan32. The process then repeats itself until the clothes are dry or the dryer10is finished with its requested cycle. A sensor13senses the dryness of the clothes within the drum14and operates to shut down the dryer10when the sensor13measures that the clothes are dry. The sensor13measures the humidity of the air within the closed loop to measure whether the clothes are dry. The sensor13also functions to estimate the time remaining before the clothes within the drum14are dry. The sensor13can thus accurately measure the wetness and/or dryness of the clothes and can adjust the time remaining to dry the clothes whether the load of clothes is large or small. The sensor13may also communicate with the valve25to open or close the valve25, as needed, as will described in greater detail below. The dryer10can also display the time remaining.

Because the dryer10of the present invention uses air that has been cycled through the closed loop and has thereby already been heated above a predetermined temperature, and at the very least above the temperature of the ambient air, the heating element36does not have to constantly be activate to maintain acceptable temperature levels that will dry the clothing within the drum14. Indeed, a temperature sensor located within the fan32, or between the fan32and the heating element36, monitors the temperature of the air within the closed loop. By monitoring the air, the heating element36can turn off when the air is measured at a temperature that is within a desired temperature range. For example, the upper limit of the desired temperature range could be between 160 and 190 degrees Fahrenheit, whereas the lower limit of the desired temperature range could be between 140 and 180 degrees Fahrenheit. In alternative embodiments the upper limit can be set at 180 degrees Fahrenheit and the lower limit can be set at 170 degrees Fahrenheit. When the temperature of the air is within this predetermined range, the heating element36does not need to consume energy to heat the air. Indeed, when the air within the closed loop reaches the upper limit of the desired temperature range, the heating element36can be automatically turned off. Then, if the air within the closed loop cools to below the lower limit of the desired temperature range, the heating element36can be automatically activated to heat the air back up to the upper limit, or at least to within the predetermined temperature range. By not having to constantly run the heating element36to constantly heat the air entering the drum14, the dryer10conserves energy.

Also, to assist in conserving energy, the speed of the fan32can be adjusted according to the needs of a particular load of laundry within the drum14. Specifically, the speed of the fan32can be automatically adjusted in accordance with the measurement of the speed, or rate, of the air flowing through the closed loop measured by the air flow sensor24. The air flow sensor24may also be configured to measure the amount of lint within the lint collector22, by measuring the rate of airflow into or out of the lint collector22, which has a direct impact on the air flow through the entire closed loop.

The dryer10can be set with a predetermined air flow speed requirement for proper drying of the clothes within the drum14. As conditions change within the closed loop of the dryer10, such as the air pressure and air flow increasing or decreasing, the speed of the fan32can be adjusted in accordance with the measurement taken by the air flow sensor24, thus using only the amount of energy to power the fan32as is necessary. For example, for light loads, for loads with little lint, or for relatively dry loads, the fan32would not have to work as hard to maintain the requisite air flow, as measured by the air flow sensor24, through the closed loop to properly dry the clothes. As a result, the fan speed could be diminished, thus diminishing the consumption of energy to power the fan32. Additionally, where the load of clothing in the drum14is large or substantially wet, the fan32may adjust its power consumption to adjust its rotational speed to maintain the requisite air flow, as measured by the air flow sensor24, through the closed loop. In this way, although the fan32is always on, the dryer10supplies the appropriate power to the fan32when needed, and also conserves power to the fan32when not needed. As an added feature, if the air flow sensor24measures a reduced or restricted air flow within the closed loop that falls below a certain predetermined level, likely due to the lint collector22being full, the air flow sensor24can communicate with both the fan32and the dryer10to shut down to avoid overworking or overloading the dryer10. Also, in this condition, the air flow sensor24prohibits future operation of the dryer10until the lint collector22is changed.

Also, as shown inFIG. 3, the dryer10further comprises a time-activated air inlet valve25that operates to allow ambient air, which is relatively cooler in temperature than the heated air within the cycle, to enter the closed loop of the dryer10at certain predetermined times during the drying cycle, if desired. The time-activated air inlet valve25can be positioned in a surface of the lint compartment18. However, the time-activated air inlet valve25can also be positioned in other locations along the closed loop, for example, in the outlet pipe28. Further, multiple time-activated air inlet valves25can be positioned at various positions along the closed loop to further facilitate the condensation of the moisture within the closed loop. The time-activated air inlet valve25can operate, for example, to allow relatively dry and cooler ambient air to enter the closed loop during the drying cycle to cool the air within the closed loop, to cool the lint compartment18, to cool the outlet pipe28, and/or to cool other components of the dryer10which might facilitate additional condensation of the moisture within the closed loop. Also, the time-activated air inlet valves25can operate during the latter stages of the drying cycle of the dryer10to cool down the air within the closed loop prior to the dryer completing the requested operational cycle to ensure the clothes are relatively cool prior to the user reaching into the drum14to remove the clothing upon completion of the cycle. Also, the time-activated air inlet valves25can operate to speed up the drying time of the load of clothing within the drum14by introducing the dry ambient air into the closed loop, which thus reduces the relative humidity within the closed loop and allows the air within the closed loop to evaporate more moisture from the clothing in the drum14. Also, as mentioned above, the ambient air also speeds up the drying time by cooling the air within the closed loop and allowing some of the moisture to condense and travel to the trap30and be pumped out of the dryer10and into the drain40.

A control unit having a processor, RAM, memory, and accompanying software and hardware components may control the operation of and interaction between the fan32, the heating element36, the pump34, the sensors24, the sensor13, the valve25, the dryer10, and any other components not specifically listed here but described herein that one of ordinary skill in the art would understand to be controlled by the control unit, as described herein. The control unit may be set by a user to run a specific pre-programmed cycle stored in the memory and the control unit may thereafter automatically run the cycle according to the selected program.

In view of the above, the cost of drying clothes in the dryer10of the present invention is between $0.22 and $0.45 per load, whereas the cost of drying clothes in the traditional exhaust dryer is between $0.60 and $1.40 per load. The cost of drying clothes in the dryer10of the present invention is approximately 3 to 7 times cheaper than drying clothes in the traditional dryer. Moreover, because the dryer10operates with heated steam within a closed loop and the lint collector22within the lint compartment18collects the lint from the clothing, the dryer10reduces the likelihood of fire and reduces the amount of carbon dioxide produced to the atmosphere.