CA2032263A1 - Ultrasonic humidifier - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

An ultrasonic humidifier has a base having a removable water reservoir connected to it. The water reservoir feeds water to an atomizing reservoir having an ultrasonic transducer connected to it. A fan generates an air stream which sweeps past the atomizing reservoir and mixes with the atomized water produced by the ultrasonic transducer to form a humidified air stream carried into a humidified air vent. A humidified air nozzle connected to the humidified air vent delivers the humidified air to the environment. A drip chute positioned partially within the humidified air vent delivers condensate noiselessly back to the atomizing reservoir into which it extends.

Description

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ULTRASONIC HUMIDIFIER
~ACKGROUND OF THE INVENTION

The invention is directed to an ultrasonic humidifier and in particular to an ultrasonic humidifier having a continuous condensed water return path from a humidified air vent to a liquid reservoir for reducing the amount of sound generated by operation of the humidifier.
It is well known that humidifiers having heating elements or ultrasonic transducers for producing a humidified air stream are often used domestically to moisten dry air within a residence, particularly during the winter months when the indoor relative humidity can drop quite low. Humidifiers also are used to increase the humidity of air within a room where a person may be suffering from a respiratory in~ection. The humidified air helps the patient to breath easier and to recover more rapidly from the infection from which he or she is suffering. It is clear that in order to obtain the benefit of the humidified air, the residents or the person being treated should be exposed to the humidified air on a continuing, rather than on an intermittent basis. As a result, a number of humidifiers have been developed which have relatively large water tanks to provide long periods of unattended operation. Some of also have controls for automatically cycling the humidifiers in response to a measured relative humidity.
In the event that large household humidifiers of the type associated with forced air heating systems are used, the noise associated with the operation of the humidifier is often not apparent to the occupants of the residence because of the general noise of the heating system. However, when a small room humidifier is used, particularly in a room in which a person is sleeping or convalescing from an infection, noise can become a more significant factor. One of the problems that humidifiers suffer from is the fact that a portion of the water or other liquid being vaporized sometimes condenses within them and drips back into the reservoir, thereby generating unwanted sound~ It is clear that when a person is ill it is important that he or she be well rested in order to recover from their illness. The noise from the operation of a conventional humidifier, particularly the dripping associated with it, because it occurs on an intermittent basis, may often keep a person awake when they should be sleeping.
A number of references related to humidifiers have come to my attention, some of which have attempted to address the problem of noise reduction, but which have failed to reduce the noise due to dripping of condensed water. Others while disclosing structures for reducing noise have impaired overall performance. When the performance of the humidifier is reduced larger components may have to be employed to allow the humidifier to perform at acceptable levels. At the same time the humidifier should be compact, lightweight and portable for the maximum convenience of the user.
U.S. Patent No. 4,810,854 to Jursich, et al., for Compact Portable Vaporizer is directed to a steam vaporizer for domestic use. The steam vaporizer employs a removable reservoir which operates in conjunction with a steam chamber connected to a steam directing conduit with a selectively positionable nozzle. The vaporizer employs an electric resistance heater 46 for heating water in a steam boiler cup 36 comprised cf a shallow stainless steel wall. The water is vaporized and ejected from the nozzle 88. It may be appreciated that such steam vaporizers of necessity must draw enough electrical energy to convert the water in the steam cup from liquid ~3~2,~

to gas or vapor. This requires relatively large amounts of energy.
A more energy efficient apparatus for producing water vapor for humidifying or medicinal purposes or the S like, is one which employs an ultrasonic transducer. The ultrasonic transducer breaks the water up into very small droplets and causes them to be ejected into an air stream where there are carried into the environment. Most of the energy needed to vaporize the water is supplied by the heat in the ambient air surrounding the humidifier.
The humidifier primarily acts to greatly increase the surface area to volume ration of the water within the humidifier to expedite ambient evaporation. Such an apparatus is disclosed in U.S. Patent No. 3,738,574 to Guntersdorfer, et al., for Apparatus For Atomizing Fluids With A Piezoelectrically Stimulated Oscillator System which discloses a piezoelectric transducer 121 which receives water from a tank 75 delivered to it via a pump 73.
U.S. Patent No. 3,901,443 to Mitsui, et al., for Ultrasonic Wave Nebulizer discloses using an ultrasonic humidifier having a transducer which is tipped with respect to the orientation of the surface of the liquid being atomized. One of the problems with using such a tipped transducer is it generates a water column which has a tendency to throw water against the wall of the exhaust duct. The water then drips from the exhaust duct back into the body of water in the water reservoir causing an annoying sound.
U.S. Patent No. 4,518,404 to Vaillant, et al., for Apparatus For Generating an Aerosol discloses an ultrasonic humidifier wherein air is drawn through a bacterial filter 5 by an aerating wheel 4. The air then flows past a quartz transducer 24 which atomizes liquid in an atomizing chamber 1. The resulting mist or aerosol 2 ~ .3 is then ejected under impetus of the aerating wheel 4 through a discharge hose 11. In an alternate embodiment, shown in FIG. 3, apertures 41 are arranged in a holder ring 9 to provide a substantially more uniform distribution of air while avoiding formation of condensation at the inner wall of the atomizing chamber 1. The quartz disk 24 in the version shown in FIG. 4 is formed on an inner side and is tipped with respect to the holder ring 42.
U.S. Patent No. 4,640,804 to Mizoguchi for Humidifier Blowoff Portion, discloses an ultrasonic humidifier directed to overcoming the problem of water accumulation between a blowoff member and an atomizing cylinder, where atomiæed water particles may become trapped in the small gap and the condensed water may be drawn out of the gap by capillary action. The alternative proposed by Mizoguchi is disclosed in FIG. 3 where "the capillary action of the water does not occur in the ring-like groove 20 because the groove 20 is so wide since only a small amount of water is could possible accumulate in the groove 20, the accumulated water does overflow from the groove 20. This is in part because for the most part the groove 20 has relatively widely spaced walls which prevent the water from being drawn out of the groove by capillary action." The rest of the ultrasonic humidifier is relatively conventional, including an ultrasonic vibrator 9 for atomizing water. The atomized water is carried out of the humidifier by an air stream generated by the air blower 12. The water, after having been atomized is carried from the atomizing chamber 14, through the blowoff member 15, which has an outlet 16 for disbursing the atomized water particles. Since the transducer is not tipped, there is less likelihood of water droplet formation on the interior wall of the atomizing chamber 14, although water droplets may still ~ ~ 3 i~

be formed thereon and drip back into the water at the bottom of the atomizing chamber 2.
British Patent No. 1,434,74~ for Improvements In Or Relating To Liquid Atomizers discloses a liquid atomizer having an ultrasonic vibrator system with an operating plate which executes bending oscillations. A
power operated blower is associated with the plate for carrying water which has been ato~ized. Other liquids or substances may also be atomized such as cosmetic liquids including and perfume and after-shave lotion. There is no teaching or suggestion in the British Patent for reducing any noise generated by dripping of recondensed material.
Japanese Published Application No. 56-59142 to lS Narisawa for Ultrasonic Humidifier discloses a humidifier where noise generated by water falling back into the water surface from which the atomized water is generated is attempted to be eliminated. A tipped ultrasonic transducer or vibrator 5 at the bottom of a misting tank generates a water column. The apparatus includes an aerosol tube 14 of relatively small diameter near the water surface above the atomizer widening out into a larger diameter so that a velocity change in the air flow rate is effected, with the air flow slowing as the air travels up the column. Packing materials 18 and 19 trap larger water droplets and prevent them from exiting the tube. The packing material 1~ also guides water back toward the reservoir surface. The use of the packing material 19 in conjunction with the packing material 18 however, decreases the amount of water in atomized form which is ejected from the humidifier as well as the air flow rate therefrom.
What is needed is an apparatus which effectively silences the noise generated by returning water droplets in an ultrasonic humidifier s~stem.

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SUMMARY OF THE INVENTION

An ultrasonic humidifier includes a base and a removable liquid reservbir unit connected to the base.
The liquid reservoir unit includes a water reservoir for holding a quantity of water or other liquid to be atomized and provided to the environment. A fan is connected to the base and generates a flow of air for carrying atomized water out of the humidifier. An ultrasonic transducer is mounted in the base and receives water from the water reservoir. The ultrasonic transducer is excited by a source of electrical energy and atomizes the water which is mixed with the flow of air to produce a humidified air stream. A substantially unobstructed humidified air vent having relatively constant interior cross section receives the humidified air stream from the ultrasonic transducer and carries the air stream at a substantially uniform speed to a humidified air noæzle. The humidified air nozzle which is connected to the humidified air vent ejects the humidified air stream to the environment. Within a humidified air nozzle is a drip chute for carrying condensed water resulting from condensation of the atomized water and ejected droplets due to the transducer. The drip chute extends into a water holding area above the transducer in order to return water to the transducer region without allowing the water to drip into the transducer water body thereby generating noise.
It is a principal object of the present invention to provide a ultrasonic humidifier having a condensed water return path extending into the water region for eliminating the noise due to dripping water.

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It is another object of the present invention to provide an ultrasonic humidifier having a substantially uniform cross section humidified air vent in combination with a drip chute to provide relatively unobstructed flow of the humidified air stream while eliminating the noise of dripping.
Other objects and uses of the present invention will become obvious to one of ordinary skill in the art upon a perusal of the specification and claims in light of the accompanying drawings.

BRIEF DESCRIPTION QF THE DRAWINGS

FIG. 1 is a front elevational view of an ultrasonic humidifier embodying the present invention;
FIG. 2 is a top plan view of the ultrasonic humidifier shown in FIG.1;
FIG. 3 is a sectional view of the ultrasonic humidifier shown in FIG. 2 taken substantially line 3--3 of FIG. 2;
FIG. 4 is a sectional view of the ultrasonic humidifier of FIG. 2 taken substantially along line 4--4 of FIG. 2;
FIG. 5 is a sectional view of the ultrasonic humidifier of FIG. 2 taken substantially along line 5--5 of FIG. 2;
FIG. 6 is a sectional view of the ultrasonic humidifier of FIG. 2 taken substantially along line 6--6 of FIG. 2;
FIG. 7 is a side elevational view of a drip 3~ chute of the ultrasonic humidifier of FIG. l;
FIG. 8 is another side elevational view of the drip chute shown in FIG. 7; and FIG. 9 is a top plan view of the drip chute shown in FIGS. 7 and 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings and especially to FIG. 1, an ultrasonic humidifier embodying the present invention is shown therein and generally referred to by numeral 10. The ultrasonic humidifier 10 includes a humidified air generator 12 having a base 14. A
removable liquid holding apparatus 16 having a liquid reservoir 18 for holding a quantity of water to be atomized, and at least partially evaporated, is removably connected to the humidified air generator 12. Means for producing a flow of air, comprising a fan 20 and a connected air duct 22, is connected to the base 14. An ultrasonic transducer 24 connected to the base 14 receives water from the liquid reservoir 18 and atomizes it. The atomized water is mixed with the flow of air from the fan 20 and the air duct 22 to form a humidified air stream and delivered to a substantially unobstructed humidified air vent 26 connected to the liquid reservoir 18. The humidified air stream is ejected to the environment by a humidified air nozzle 28 connected to the humidified air vent 26. A means for noiselessly carrying back condensed water, comprising a drip chute 30, is connected to the humidified air vent 26 and extends into a secondary liquid or atomizing reservoir 32.
Referring now to FIGS. 1 and 2, the removable liquid holding assembly 16, including liquid reservoir 18, is substantially rectangularly shaped and has a pair of rectangular end walls 34 and 36 joined by elongated rectangular sidewalls 38 and 40. The walls 34 and 38 are connected by a rounded corner section 42. The walls 36 and 38 are connected by a rounded corner section 44. The walls 36 and 40 are connected by a rounded corner section 45. The walls 40 and 34 are connected by a rounded : 35 ;

corner section 48. A top wall 50 is joined to walls 34, 36, 38 and 40 and has an indentation 52 formed therein with a handle 54 positioned within the indentation 52.
The indentation 52 allows one wishing to lift the removable liquid holding assembly 16 off the humidified air generator 12 to easily grasp the handle 54. The walls 34, 36, 38, 40 and 50, as well as the integral corner regions 42, 44, ~6 and 48, are formed of plastic, in particular . The nozzle assembly 26 is interfitted into the top wall 50 in pivoting engagement therewith. The walls 34, 36, 38, 40 and 50, as well as the corner regions 42, 44, 46 and 48 in conjunction with the humidified air vent 26 define a chamber 56 containing water for delivery to the humidified air generator 12.
The bottom wall 54 has formed therein a valve assembly 58 comprising a valve closure 60 connected to a valve stem 62 biased by a spring 64 against a valve seat 66. When the liquid holding assembly 16 is removed from the humidified air generator 12, the valve assembly 58 is normally closed, preventing any water or other liquid within the chamber 56 from leaving the removable liquid holding assembly 16. When the removable liquid holding assembly 16 is fitte~ onto the humidified air generator 12, a portion of the air generator 12 biases the valve stem 62 upwardly to move the valve closure 60 off the seat 66, allowing water to flow into the humidified air generator 12. A threaded closure and seat assembly 70 is also formed in the bottom of the liquid reservoir,18 and when the removable liquid holding assembly 16 is removed from the humidified air generator 12 a screw plug from the threaded assembly may be removed in order to fill the chamber 56 with water 72. In order to interfit the removable liquid holding assembly 16 with the humidified air generator 12, an internal shoulder 78 is provided with interfits with portions of the air generator 12 as set forth below.

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Referring now to FIGS. 4, 5, 6, 7, 8 and 9 wherein the drip chute 30 is shown, the drip chute 30 includes an upper shoulder portion 80 connected to the humidified air vent 26. The drip chute 30 extends at an angle through the humidified air vent 26 into the humidified air generator 12. The drip chute 30 includes a pair of curving wall sections 82 and 84 joined by a step section 86. The drip chute 30 extends far enough into the air generator 12 so that a bottom edge 88 of the drip chute 30 lies below a water level within the atomizing reservoir 32 so that condensed water does not fall freely back into the humidified air generator 12, but rather slides down the sloping walls of the drip chute 30.
The humidified air generator 12 includes a bottom wall 100, an end wall 102, a second end wall 104 and a pair of side walls 106 and 108. The walls 102, 104, 106 and 108 terminate in a continuous shoulder portion 110 which engages the shoulder portion 78 of the removable liquid holding assembly 16 when the units are placed together. When the removable liquid holding assembly 16 is loaded with water and placed on top of the humidified air generator 12 the valve stem 62 is biased upwardl~, allowing the water 72 to flow into the atomizing reservoir 32 which comprises a pair of side walls 114 and 116, a bottom wall 118 and a pair of side walls 120 and 122. The atomizing reservoir 32 opens into the humidified air vent 26. The ultrasonic transducer 24 is mounted on the bottom wall 118 so that it is in good mechanical connection with water 122 within the atomizing reservoir 32. It should be appreciated that as shown in FIG. 6 the ultrasonic transducer 24 is tipped downward at about a 25~ angle. The humidified air generator 12 includes the fan 20 and the air duct 22. The air duct 22 includes a horizontal portion 126 and a chimney or ~3~

vertical portion 128. Air is driven through the horizontal portion 126 into the chimney portion 128 where it is delivered to the region of the humidified air s~ent 26. The air then moves up the humidified air vent 26 and exits through the humidified air nozzle 28 to the environment. As the air is moving it is mixed with and carries atomized water droplets produced by the ultrasonic transducer 24 from the water 122 in the atomizing reservoir 32. Atomized water which condenses or would normally tend to land on the interior of the humidified air vent 26 lands on the drip chute 30. The step portion 86 separating the curving wall portions 82 and 84 of the drip chute 30 prevents the water from moving a substantial distance horizontally on the drip chute 30. It channels the water so that it slides down the drip chute 30 and reenters the body of water 122 in the atomizing reservoir 32. It should be appreciated that the bottom edge 88 of the drip chute 30 extends below the bottom wall 54 of the liquid reservoir 18 and 2 into the atomizing reservoir 32 a sufficient distance so that it is submerged in the water 122. The water level is maintained within the atomizing reservoir 32 until the water in the liquid reservoir 18 is exhausted. This prevents the returning water or condensate from noisily dripping back into the water 122, rather it is returned silently.
The ultrasonic transducer 24 is driven in a conventional fashion by a power supply which includes a transformer 132. An intensity control 134 and a humidistat control 136, as are conventional in ultrasonic humidifiers, control the operation of the transducer 24.
The base 14 includes a plurality of feet 138 which support it on a surface and allow air to be drawn in through the base 14 by the fan 20, passed through the air duct 126 and out the chimney 128.

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It may be appreciated that the drip chute 30 provides a means whereby the atomized water which would normally fall back noisily into the water 122 is returned noiselessly without substantially slowing down the velocity of the air exiting the substantially unobstructed humidified air vent 26, thus allowing a relatively small fan to be used in the ultrasonic humidifier 10. The step portion 86 of the drip chute 30 prevents the atomized water droplets falling upon the wall sections 82 and 84 from splashing off or continuing around and operates as a gutter to channel the water back into the body of water 122 noiselessly.
While there has been illustrated and described a particular embodiment of the present invention, it will lS be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.

Claims (7)

1. An ultrasonic humidifier, comprising: a base; a liquid reservoir connected to said base for holding a quantity of water to be atomized; means connected to said base for producing a flow of air; an atomizing reservoir connected to said base and receiving water from said liquid reservoir; an ultrasonic transducer connected to said atomizing reservoir and atomizing the water where it is mixed with the flow of air to produce a humidified air stream; a substantially unobstructed humidified air vent for receiving the humidified air stream from said ultrasonic transducer and carrying it at substantially uniform speed; a humidified air nozzle connected to said substantially unobstructed humidified air vent for ejecting the humidified air stream; and means connected to said liquid reservoir and to said substantially unobstructed humidified air vent, for carrying condensed water resulting from condensation of the atomized water in the humidified air stream within said humidified air vent to said liquid reservoir without the condensed water dripping into the water in said liquid reservoir.

2. An ultrasonic humidifier as defined in claim 1, wherein said means for carrying the condensed water comprises a drip chute extending through said humidified air vent.

3. An ultrasonic humidifier as defined in claim 2, wherein said drip chute extends into said atomizing reservoir.

4. An ultrasonic humidifier as defined in claim 3, wherein said liquid reservoir further comprises a bottom wall and wherein said drip chute extends below said bottom wall of said liquid reservoir.

5. An ultrasonic humidifier as defined in claim 2, wherein said drip chute comprises a first arcuate wall, a second arcuate wall and a step wall connected to said said first arcuate wall and said second arcuate wall for interrupting transverse motion of condensed water deposited on said drip chute to return the condensed water noiselessly to the atomizing reservoir.

6. An ultrasonic humidifier as defined in claim 2, wherein said means for producing a flow of air further comprises a fan.

7. An ultrasonic humidifier as defined in claim 2, wherein said liquid reservoir is removably connected to said base.