This disclosure relates to high frequency drying and more specifically to systems and processes that improve drying efficiency.
Conventional clothes dryers use an energy source such as natural gas or electricity to dry clothes. A gas or electric heater heats air that passes through the clothes as they tumble and turn. Moisture is removed from the clothes via the heated air by converting the water retained in the clothes into vapor, which requires a substantial amount of continuous energy. The heat that dries the clothes is then removed and exhausted from the dryer.
Besides the inefficiency and the cost of converting cold air into hot air, water into vapor, and venting hot wet air, conventional clothes dryers also pose safety hazards. When the temperature exceeds a safe operating threshold, the dryers can overheat, damaging the clothes, the dryer, and the structures near them. Such failures can occur when airflow is restricted or when a dryer's thermal cutoff switch fails. There is a need for a system and process that provides a more efficient, less expensive, and a safer process to dry clothes. A technical challenge addressed by this disclosure is that of improving the efficiency of the drying process so that it may be used safely in vented and ventless systems.
The disclosed high frequency technology is clean, efficient, and environmentally friendly. The collection of systems and processes disclosed are herein referred to as “the systems”. The systems may be adapted to existing dryers including blower and lint filter dryers, drum shroud dryers, and integrated drum shroud dryers. The systems may also be adapted to new innovative dryer designs including wringer type dryers and sandwich press/iron dryers. The innovation overcomes technical problems in the clothing industry, paper industry, food industry, mining industry, environmental industry, and in chemical manufacture, to name a few. It is used in stand-alone systems and large-scale enterprise systems. The systems' high frequency mesh transducers convert electrical signals into high frequency mechanical waves. They also convert ultrasound and mechanical waves into electrical signals when not powered by electrical signals. The technology makes use of high frequency transceivers that both (a) sense pressure and high frequency signals and (b) transmit pressure and high frequency signals. High frequency signals include ultrasonic signals that generate waves having a frequency above twenty thousand cycles per second.
One or more high frequency generators (also known as a high frequency controller, controller, amplifier, driving power driver, or drive controller) control the duty cycle and resonant frequencies that drive the high frequency transducers/transceivers (herein referred to as high frequency piezoelectric transducers). A drying effect is achieved by vibrating an article through piezoelectric and substrate elements and one, two, or three or more separate meshes within about a 100 Hz to 400 kHz range with a preferable irradiation frequency of about 130 kHz. Other frequencies for irradiation are also possible including about 50 kHz to about 90 kHz, about 100 kHz to about 1 MHz and about 500 kHz to about 2 MHz. The separate spaced apart meshes comprise a plurality of distinct mechanically actuated grids formed by the intersection of wires, polyester lines, or nylon lines, (or a combination) for example; where each mesh is flexible and capable of independent movement. The high frequency transducers/transceivers are driven at a duty cycle within a range of substantially 1% to substantially 30% or more. The transducer duty cycle may be varied throughout the clothes drying cycle process as a function of moisture level. Higher duty cycles are possible including about 40% or about 50%, and up to about 90% approaching 100%. During a drying process, capillary waves form on the surface of liquid retained in an article. The wavelength of the capillary waves depends on the irradiation frequency of the high frequency transducers/transceivers. When oscillated with sufficient intensity (amplitude), the water pinches off into droplets that pass through the spaced apart meshes that partially overlay an open inner annular area bounded by the piezoelectric and substrate elements and passes through a cylindrical shroud outlet. The water then passes through collector channels that terminate at a reservoir or a drain. Unlike conventional dryers that rely on heat energy to evaporate fluid retained by an article into vapor, the disclosed high frequency transducers use mechanical energy and vibrational energy. The term article in this disclosure refers to the object being dried such as a fabric.
In
In some alternative systems the duty cycles of the actuated high frequency mesh transducers 100 are determined by the rotational rate of the hollow rotary tumbler drum 108 and the proportional feedback signal generated by the force that is applied by the articles against the high frequency mesh transducers 100. In these alternative systems, as the articles dry the weight of the articles and the proportional feedback voltage signals generated by the high frequency mesh transducers 100 decrease. In turn, this causes the burst-width modulated signal delivered by the high frequency generators to increase. Notably, the power consumed by some high frequency systems is inversely related to the level of moisture retained in the articles or the article's weight and may be used to calibrate the high frequency generator when the articles are first loaded within the rotary tumbler drum 108. In operation, when articles are initially loaded, high frequency generators drive the high frequency mesh transducers 100 at their resonant operating efficiency based on the detected moisture or weight. As the articles eject the liquid or a predetermined amount of the liquid, some high frequency generators proportionally increase the power sourced to the high frequency mesh transducers 100 by increasing the duty cycle sourcing the high frequency mesh transducers 100 as shown in
While each of the systems described in this disclosure are shown in vent-less systems, other systems incorporate the high frequency technology in vented systems. For example, when retrofitted to a conventional blower lint filter dryer, the high frequency systems may alternatively or additionally couple a lint filter that overlies an array of high frequency transducers or high frequency mesh transducers 100 that include a series of meshes serially aligned, stacked, and spaced apart in an array. When the liquid droplet sizes in the irradiated mist are of appropriate size, they are entrained in the airflow and transported out of the hollow rotary tumbler drum 108 through the lint filter and other meshes serially stacked and aligned that make up part of the high frequency mesh transducers 100. The liquid droplets coalesce into larger droplets that are then collected in collector channel 110 that terminates at a reservoir or passes to a drain and the dehumidified airflow is exhausted through a vent. In
While the number of meshes, opening size, and materials used to manufacture the meshes used in the high frequency mesh transducers 100 depend on the application and the type of liquid being extracted from an article, polyester mesh with opening size of about 0.84×0.84 mm are effective when operating in environmental conditions common to consumer clothes dryers. The opening size of the mesh is similar to that of a lint filter and the optimum number of spaced apart, directly adjoining meshes stacked in series (overlying each other above the piezoelectric and substrate elements spaced apart by only by a flat ring made of metal or plastic such as O-rings) is three, which results in a moisture collection efficiency of about 50%. As additional meshes are added in series the cumulative airflow pressure drops along with the moisture collection efficiency.
Because drying occurs when direct contact occurs between an article and one of the mesh layers of the high frequency mesh transducers 100, the high frequency mesh transducers 100 are not activated or powered-up continuously resulting in an energy consumption that is between two to five times less than the energy consumed by conventional dryers. In operation, when the high frequency mesh transducers 100 are activated, the high frequency mesh transducers 100 push the article upward away from the high frequency mesh transducers 100. When contact is lost, power is not sourced to the high frequency mesh transducers 100, meaning that the power is delivered only in bursts when contact occurs between the article and the high frequency mesh transducers 100. After a finite amount of time, the article falls back into contact with the high frequency mesh transducers 100 due to gravity, and in some cases centrifugal force. While direct contract with the high frequency mesh transducers 100 reoccurs, detection occurs when the articles mechanically stress the high frequency mesh transducers 100. In other systems passive sensors such as passive infrared sensors detect direct contact between the articles and the high frequency mesh transducers 100. The term passive in this instance refers to the fact that sensors do not generate or radiate any energy during the detection process.
The energy consumed per unit mass of water is calculated as:
When applying different duty cycles and frequencies, exemplary high frequency mesh transducers 100 which typically operate at resonance frequency of 130 kHz and modulated by modulation frequency of about 600 Hz at about a 60% duty cycle. The minimum energy consumption per unit mass of water is about 0.198 kWh/kg, which is about half the energy consumed when the high frequency mesh transducers 100 were powered up continuously. This is about ⅕ of the energy that is used in the conventional electric dryers.
In
To deliver power, the driver and power distribution architecture may use a slip-ring, a rotary electrical joint, a collector or an electric swivel. The slip ring keeps continuous connections with the high frequency mesh transducers 100 that are part of the hollow rotary tumbler drum 108 as shown in
While each of the disclosed high frequency technology described may stand alone they also may be encompassed within other systems and applications. Other alternate systems may include any combinations of structure and functions described above or shown in one or more or each of the FIGS. These systems or methods are formed from any combination of structure and function described. The structures and functions may process additional or different high frequency mesh transducers 100 and may be supported by other drying structures than a hollow rotary tumbler drum 108, for example. Other high frequency mesh transducers 100 that may be used for example, may apply several widely different frequency signals to one or more articles to affect the drying process include those that have separately tuned piezoelectric and substrate mediums aligned in a stack as shown in
Other systems include variations of the spaced apart meshes that comprise a plurality of distinct mechanically actuated grids having penetrations that allow various types and viscosities of liquids to pass there through. Some, all, or combinations of the perforated meshes shown are stacked in the high frequency mesh transducers 100 as described above. The spaced apart holes, slots, random perforations, and radial slots with perforated and/or solid reinforcement bars and all combinations thereof are preferred because various meshes and combinations draw water from various articles more effectively and efficiently than others. The combinations and piezoelectric elements provide means to remove nebulized water droplets from a working side of an article. A working side is the side of the article in direct contact with one of the meshes of a high frequency mesh transducer 100. When part of the mesh transducer is in contact with a wet article, a nebulized liquid flow path is established for continuous liquid removal. When solid transducers are used in other alternative systems a flow path is provided to channel nebulized liquid droplets away from the articles.
In each of the systems described meshes are excited by the piezoelectric-medium fixed to a substrate. When powered, the contraction and expansion of the piezoelectric-medium subjects the substrate into bending vibrations. The bending of the substrate excites the mesh vibrations substantially perpendicular to the piezoelectric-medium vibrations. In these systems, the piezoelectric medium and substrate is optimized to a vibration frequency of about 100 Hz to about 400 kHz, preferably 130 kHz and its shape is matched to the deflection shape of the substrate. To ensure the irradiation fluid passes through the high frequency mesh transducers 100, the piezoelectric medium may comprise a piezoelectric-actuator annulus and the substrate may comprise an annulus concentric with the piezoelectric-actuator and coupled at least one mesh along an inner radial portion of the substrate. The meshes are separated preferably by about a one-eighth of an inch open annual O-ring on the upper and lower mesh surface. The mesh surfaces are positioned with the piezoelectric-actuator annulus and the substrate annulus within a hollow right circular cylinder shroud.
All or parts of the high frequency generator may include or be controller by one or more controllers, one or more microprocessors (CPUs), one or more signal processors (SPU), one or more graphics processors (GPUs), one or more application specific integrated circuit (ASIC), one or more programmable media or any and all combinations of such hardware including ultrasonic generators, ultrasonic controllers, ultrasonic microprocessors, ultrasonic SPUs, ultrasonic GPUs, ultrasonic ASICs, etc. All or part of the logic, specialized processes, and systems may be implemented as instructions for execution by multi-core processors (e.g., CPUs, SPUs, and/or GPUs), controller, or other processing device and stored in a tangible or non-transitory machine-readable or computer-readable medium such as flash memory, random access memory (RAM) or read only memory (ROM), erasable programmable read only memory (EPROM) or other machine-readable medium such as a compact disc read only memory (CDROM), or magnetic or optical disk. Thus, a product, such as a computer program product, may include a storage medium and computer readable instructions stored on the medium, which when executed in an endpoint, computer system, or other device, cause the device to perform operations according to any of the process descriptions or hardware descriptions above.
The term “coupled” disclosed in this description may encompass both direct and indirect coupling. Thus, first and second parts are said to be coupled together when they directly contact one another, as well as when the first part couples to an intermediate part which couples either directly or via one or more additional intermediate parts to the second part. The term “substantially” or “about” encompass a range that is largely (ninety five percent or more), but not necessarily wholly, that which is specified. It encompasses all but a significant amount. When devices are responsive to or occur in response to commands events, and/or requests, the actions and/or steps of the devices, such as the operations that devices are performing, necessarily occur as a direct or indirect result of the preceding commands, events, actions, and/or requests. In other words, the operations occur as a result of the preceding operations. A device that is responsive to another requires more than an action (i.e., the device's response to) merely follow another action.
While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.
This application is a continuation of International Application No. PCT/US2016/030885 and claims priority to U.S. Provisional Patent Application No. 62/158,562, filed May 8, 2015, titled “Clothes Dryer Using Ultrasound Phenomena”, both of which are herein incorporated by reference.
This invention was made with United States government support under Contract No. DE-AC05-000R22725 awarded by the United States Department of Energy. The United States government has certain rights in the invention.
Number | Date | Country | |
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62158562 | May 2015 | US |
Number | Date | Country | |
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Parent | PCT/US2016/030885 | May 2016 | US |
Child | 15798057 | US |