The present invention relates to the field of room humidifier devices, and more particularly to an ultrasonic humidifier providing for REDUCED aerosolization of pathogens and dissolved solids found in source water.
There is a growing body of evidence on the health benefits of maintaining proper indoor humidity. For example, recent studies have shown that increasing indoor humidity from 20% to 40% can decrease influenza infection rates by 80%. A humidifier is an electrical appliance designed to increase humidity in a single room or an entire building. It is estimated that 15% of American homes have a humidifier.
Ultrasonic humidifiers are believed to be the most prevalent type of humidifier, at least for the consumer market, as they tend to be the most efficient and have the lowest cost compared to the alternatives. Such humidifier devices typically use a ceramic piezoelectric diaphragm vibrating at an ultrasonic frequency to create water droplets that exit the humidifier in the form of cool fog with little or no perceived noise, which is desirable.
However, there is a significant problem with these types of humidifiers. Studies show such ultrasonic humidifiers aerosolize 90% of the impurities found in the device's water reservoir. The impurities include inorganic minerals and dissolved solids (TDS) found in the source water (and in all tap water) as well as any organic pathogens such as bacteria that can grow in the stagnant charge water while it is contained in the device's water reservoir. Most consumers are unaware their humidifier will increase the airborne particle count by 20× in a matter of minutes. As a result, ultrasonic humidifiers must be cleaned regularly. Consumers would need to use distilled water as the source water to prevent airborne pathogens and avoid a sticky white dust being spread throughout the air, and the resulting airborne dispersion of impurities in the water. Unfortunately, distilled water is not as readily available to the consumer as tap water, and most consumers use tap water as the source water.
The impurity-inhalation and other potential risks associated with ultrasonic humidifiers have been investigated by many researchers in the past. The risks are associated with fine particulate matter generated from the humidifier operation. These studies determined the mass concentration, chemical composition, morphology, size distribution and the total numbers of particulate matter generated by an ultrasonic humidifier, and scientifically established that particulate matter emitted from humidifiers is composed of inorganic compounds having a composition directly mirroring that in the charge water. These studies concluded that the size and mass concentration of particulate matter both increase with the amount of solute in the charge water.
Some manufacturers have added UV light sources/filters to remove organic pathogens. Such UV treatment has no effect upon the inorganic solids (TDS). Some manufacturers have implemented a cleaning mode in which detergents/cleaning solutions such as citric acid are used to clean the water tubing to reduce accumulations of the organic pathogens. Such cleaning solutions have no effect upon the problems associated with the inorganic solids/TDS, and sometimes they result in water contamination.
As an alternative to ultrasonic humidifiers, evaporative humidifiers do not aerosolize the dissolved solids. However, such evaporative humidifiers pose other problems. For example, such evaporative humidifiers use wicks that become moldy and can become saturated with mineral deposits over time. Further, they are less efficient than ultrasonic humidifiers and are unable to regulate their humidification rate.
As another alternative to ultrasonic humidifiers, vaporizers or steam humidifiers are less likely to aerosolize impurities in the water. However, they use a substantial amount of energy compared with ultrasonic humidifiers and they pose far greater health safety risks, including fire and burn risks.
There is a need or desire for a humidifier that can provide for safe operation using impurity-laden tap water, which reduces or prevents aerosolization of inorganic minerals and dissolved solids found in source tap water, and airborne pathogens, and avoids harmful impacts to humans resulting from the inhalation of such airborne particles.
The present invention provides a humidifier that provides for safe operation by reducing or preventing aerosolization of inorganic minerals and dissolved solids found in source water, and airborne pathogens, and avoids harmful impacts to humans resulting from the inhalation of such airborne particles.
An understanding of the following description will be facilitated by reference to the attached drawings, in which:
Operation of known room air humidifier appliances can increase room air humidity, but they often introduce airborne contaminants into the room air, which is undesirable and can be harmful to one's health if inhaled. The contaminants include bacteria and other pathogens that may be found in the source water, such as tap water, and/or that may grow within the water reservoir or elsewhere within the device. In the case of ultrasonic humidifiers, the airborne contaminants may include minerals and/or other materials present as dissolved solids in the source water. Unfortunately, distilled water is not as readily available to the consumer as tap water and most consumers do not use distilled water, but instead use tap water as the source water, which provides such contaminants. The present invention provides a humidifier device that provides for safe operation by reducing or preventing aerosolization of inorganic minerals and dissolved solids found in source water and airborne pathogens, and thereby avoids harmful impacts to humans resulting from the inhalation of such airborne particles.
Many conventional ultrasonic humidifiers position an upper water tank above a lower reservoir containing a water-atomizing piezoelectric disc or other humidification structures, rely upon gravity to move water into the reservoir, and provide for substantial water accumulation and length of passage of water vapor through the humidifier 100 that can promote undesirable bacterial growth. By contrast, the exemplary embodiment of the present invention positions the water tank 20 below an upper humidification chamber 90 that is at or near an exit point of the humidifier 100. This reduces water accumulation and length of passage of water vapor through the humidifier 100, and thus reduces or eliminates opportunities for bacterial growth. Instead, the water from tank 20 is first filtered by filter 40. The filtered water is then pressurized by a pump 60 and pumped to the upper humidification chamber 90 at or adjacent an exit point of the humidifier 100, near the fan 70 and upper end of the housing 10, as will be appreciated from
The humidifier 100 includes a water filter 40 configured to filter debris and/or dissolved solids, such as minerals, from charge water contained in the water tank 20. The water filter 40 can be positioned upstream from the UVC filter 50, the pump 60 and the humidification chamber 80, so that atomized water has already been filtered and cleaned before reaching the humidification chamber 90. This avoids the release and dispersion of dissolved solids into the room air.
The humidifier 100 may include the UVC filter 50, which can be a UV-C light source (which may include a broad-band light source and/or a UV-C filter), positioned to expose charge water from the water tank 20 and upstream from the humidification chamber 90 to a dose of UV-C radiation. The dose of UV-C radiation can be operable (in combination with flow rate, etc.) to kill pathogens contained in the charge water that would otherwise be dispersed into room air. As shown in
In accordance with the present invention, tubing connecting each individual component and the individual components themselves are coated or impregnated with antimicrobial or hydrophobic additives to further avoid pathogen growth within the humidifier 100. This is particularly applicable to tubes 46 and 56 between the water filter 40 and pump 60, and tube 66 between the pump 60 and humidifier chamber 90. Such coatings can also be applied to inlet tube 30 which draws water from the water tank 20 to the water filter 40, and overflow tube 98 that carries overflow water from the humidifier chamber 90 back to the water tank 20.
In accordance with the present invention, the housing 10 may include a cover 14 which can be cylindrical as shown in
Referring now to
The exemplary water tank 20 can include a lid 24 configured to form a close fit with a top of the reservoir 22. The lid 24 can include an outlet port 26 and an inlet port 28. The outlet port 26 is connected to inlet tube 30 for drawing water from a bottom of the reservoir 22, and the output port 26 provides a fitting 27 for connecting tube 46 for passing water drawn from the reservoir 22 to the pump 60. In this embodiment, the water filter 40 can be removably attached to a lid housing 42 (
The water filter 40 can be constructed to provide an elongated (e.g., maze-like) route of passage through filtration media of the water filter 40 to optimize filtration capacity and/or effectiveness. In one embodiment, the water filter 40 can be made of inorganic material with ion extraction properties. By way of example, the water filter 40 may employ resin beads, a reverse osmosis filter and/or activated carbon as filtration media materials.
More specifically, the filtration media of water filter 40 can be made of technological materials like resin that are able to capture and retain inorganic compounds from the water flow. Usually, the goal is to maximize the trajectory length of a given water volume element through the filter, such that contact time with the absorbing material is extended. Therefore, the water filter 40 may be constructed to increase the water flow hydrostatic resistance due to restricting the effective flow area. The resistance may be elevated during the initial priming of the water through the filter or when the filter gets clogged with minerals from the water. In certain embodiments, the device may include a control system 99 providing pump control logic that accounts for water filter resistance, as discussed below with reference to
As will be appreciated from
The UV light source 50 may be an in-line or an external application of UV light from UV-capable bulbs or LEDs, preferably UV-C light, that provides light capable of breaking down the DNA, RNA and/or proteins of organic pathogens such as bacteria, fungi, virus, and animal and plant cells and thus “kills” these pathogens. The light source 50 may include one or more external LEDs in parallel that illuminate a transmissible section of the LED and may have reflective surfaces. The degree of germicidal effectiveness is related to the dose rate on the incident surface. The dose is a product of intensity and exposure time in seconds.
The dose rate and distance between the UV light source and a central streamline of the tubing are two key factors that determine the effectiveness of sterilization. By way of example, the UV irradiation intensity can be reduced up to 80% at a distance of 10 cm from the light source. Effectiveness is also impacted by the length of the UV light source segment as well as by the water flow rate. UV LEDs may draw several watts of electricity, and appropriate heat sinking measures may be taken to dissipate the outside the device.
The UV light source 50 may be positioned adjacent fused silica or quartz tubing, and UVC light emitting diodes and enclosure may be provided to limit UV light leakage. The UV light source 50 can be connected to a respective power electronics and controlled by a centralized microcontroller of the control system 99 (
The pump 60 may be a peristaltic constant displacement pump equipped with antimicrobial pump tubing. The pump head may be driven with a direct current electrical motor, which in turn is controlled by a power amplifier and the control system 99. Primarily, the pump is operable to draw water from the water tank 20, through the water filter 40, along the UV light source 50, and to deposit such water in the humidification chamber 90 for atomization purposes.
In certain embodiments, the pump's operation can be reversible to move water in both the forward and backward directions. For example, the forward pump action may be used to supply the humidification chamber 90 with water and the backward direction may be used to drain water from the humidification chamber 90 system back into the water tank 20.
As will be appreciated from
In accordance with the present invention, the humidification chamber 90 may have any suitable structure. In the exemplary embodiment of the present invention, the humidification chamber 90 has an upper vent 91 and further includes at least one ultrasonic piezo disk 92 having a watertight cap disk 92A and mounted on top a wick carrier disk 94 that provides a plurality of watered cylindrical wicks 93. The wick carrier disk 94 is sized to enable the watered cylindrical wicks 93 to be partially submerged into a dedicated water supply reservoir 96 that is contained within the wick carrier disk 94, as best shown in
The water supply line for the wicks 93 can be designed as a small buffering reservoir 96 that is supplied with the pump outflow. The reservoir 96 may include a spillway draining to overflow tubing 98 passing from the spillway back to the inlet port 26 and associated fitting of the water tank lid 24. In certain embodiments, the humidification chamber 90 is further provided with an overflow valve that cycles excess clean water back to the water tank 20 to prevent leakage from the top side. A more detailed explanation and description of an exemplary piezo disk and wick carrier disk assembly is provided in a copending application Ser. No. ______ filed by the same Applicant of even date herewith, entitled “Humidifier With Improved Mist Generation,” the disclosure of which is incorporated by reference.
It will be appreciated that the water filter 40, UV light source 50 and pump 60 can be organized in any order, but to maximize the filtration performance, particular pump characteristics, water filter structure and UV light source power should be considered, and parameters should be coordinated to provide the desired efficacy. Continuous or periodic water flow through the water filter 40 and past the UV light source 50 promotes proper water sterilization.
The control system 99 can be operatively connected to the system components to provide a suitable signal to the components to control the humidifier device. As will be appreciated by those skilled in the art, the control system may comprise a printed circuit board supporting electrical components implementing suitable logic for carrying out the functionality described herein.
Generally speaking, the control system is composed of hardware level and software level layers. With respect to the software level, the control system may be implemented as an executable entity in a dedicated microcontroller integrated circuit (IC). The control algorithm is commonly performing discrete-event functions. The control software of the humidifier is a composition of various loops of control dedicated to various functions requested by the device.
In addition to the tubing described above, various components of the humidifier 100 can be made using plastic whose exposes surfaces can be embedded with antimicrobial and/or hydrophobic additives. These include the water tank 20, the housing enclosure 10, and the UVC filter 50, for example. The inventive humidifier 100 can reduce the amount of water minerals projected into the air to zero or close to zero and is able to reduce the amount of pathogens projected into the air to near zero. The humidifier 100 can maintain a 2-log or better continuous reduction of microbes from the source water, such as tap water, and the use of antimicrobial and/or hydrophobic additives in and on the exposed equipment surfaces block additional microbial generation. The humidifier 100 can maintain the sterility of any stored water for several days by repeatedly circulating the water through the water filter 40 during periods of use.
While there have been described herein the principles of the invention, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation to the scope of the invention. Accordingly, it is intended by the appended claims, to cover all modifications of the invention which fall within the true spirit and scope of the invention.
This patent application claims the benefit of U.S. Provisional Application Ser. No. 63/296,043, filed on Jan. 3, 2022, the disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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63296043 | Jan 2022 | US |