This invention relates generally to a portable humidifier and, more specifically, to a portable humidifier with an improved water tank.
Various types of humidifiers are used to provide moisture to indoor air. Included among such humidifiers are ultrasonic humidifiers, steam humidifiers or vaporizers, and evaporative humidifiers.
Ultrasonic humidifiers employ a high-speed oscillator, positioned a given distance below the water surface, to energize the water and break it into a fine mist. A fan carries the mist into the surrounding environment. It is critical that the distance from the oscillator to the water level be accurately maintained to ensure that the oscillation energy is efficiently transferred to the water. A drop in water level can result in permanent damage to the oscillator. The water level generally is maintained by the use of an inverted water tank such as that described in U.S. Pat. Nos. 5,210,818 and 5,247,604. The tank is sealed and includes a carrying handle on its top surface while a bottom surface includes an opening to which a cap is attached. When the tank is inverted beneath a spigot and the cap is removed the opening serves as a fill opening. Often the cap includes a valve system which seals the fill opening unless the tank is properly positioned on a humidifier base and the valve is engaged by a valve actuator in the base. The valve actuator opens the valve and allows water to escape from the tank into a reservoir defined by the base. Discharging water is exchanged for air which enters the tank through the same opening. As water flows into the base reservoir, the water level rises until it seals the valve and prevents air from getting into the tank. At this level, which is the normal operating water level for the humidifier, water flow from the tank ceases. The design of the humidifier is established to position the oscillator that given distance below this level. As the oscillator and fan cause dispersal of moisture from the reservoir, the water level attempts to drop creating a pathway for air into the tank and in turn allowing the release of a proportional amount of water from the tank into the reservoir to thereby return the water level to the normal operating level. This process repeats itself continually until the water supply in the tank is depleted, at which time the water level begins to drop increasingly lower. A float sensing shut-off switch mechanism senses the abnormally low water level and turns the humidifier off before the water level drops low enough to cause damage to the oscillator. This basic system is well known and often practiced in ultrasonic humidifiers of the prior art.
Evaporative humidifiers come in several varieties. Some employ absorbent belts continuously rotating through first a water reservoir and then an air stream to cause humidity. Some employ pumps to lift water from a reservoir and pour it over a porous media through which air flows to cause similar humidification, and some employ wicking pads which are positioned partially below water level and partially above. In such humidifiers, the water level must be maintained for a different reason than that of the ultrasonic humidifier. Specifically, it is important that water level be maintained to ensure consistent humidity efficiency and maximum moisture output. Wick pads generally are capable of drawing water from the reservoir water level to a given height through capillary action. A relatively smaller portion of the wick pad must be positioned below the water level where water is absorbed, than above where air flowing through the pad causes the desired humidification. Excessive height of the pad above that height to which water will be drawn not only constitutes wasted wick material and is therefor inefficient by design, but also reduces the humidification efficiency of the humidifier by allowing a pathway for air which does not pass through the moistened portion of the pad, essentially constituting air leakage which reduces the total humidification rate. For this reason, wick type evaporative humidifiers are often designed to maintain a given water level which ensures that the most efficient amount of the wick pad lies above and below the water level to maximize efficiency and output. Accordingly, a water tank similar to that described above often is used with evaporative humidifiers.
Steam humidifiers cause humidity by boiling water into vapor. A submersible heating element depends from a humidification unit into a boiling chamber within a base. A water tank similar to that described above is positioned on the base to both feed water to the boiling chamber and to maintain a given normal operating level therein. The boiling water maintains the temperature of the heating element at approximately two hundred and twelve degrees fahrenheit. It is important that the water level be maintained high enough to fully submerge the heating element, and not be allowed to drop while the heating element is energized or overheating will occur. A float sensing shut-off switch mechanism senses an abnormally low water level as the water tank is depleted and turns the heating element off before excessive overheating occurs.
Most of the tanks described above and known in the prior art include a handle projecting from a tank top surface. Such positioning of the handle requires that the tank be carried from the humidifier to the spigot cap with the fill opening facing down. It is common for some leakage to occur from the cap during such movement. It is also common that, after being carried to a water supply, the tanks are rested on a surface with the fill opening facing down. Although usually protruding precariously from the bottom surface of the tank, prior cap/valve assemblies have not generally provided a great amount of structural support, and being that a filled water tank is relatively heavy, the weight of the tank resting on the cap/valve assembly can subject the valve to an enormously high amount of stress. Consequently, permanent damage to valves is relatively common and often results in water spillage that damages furnishings.
It is the object of the present invention to overcome the deficiencies of the prior art and provide a humidifier tank having a tank support structure which serves both to protect the delicate cap/valve assembly and provides a means by which the tank can be carried hole side up to prevent leakage during transport.