US 3152245 A
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Description (OCR text may contain errors)
Oct. 6, 1964 A.L.UTMAN INFRARED NURSING BOTTLE HEATER Original Filed May 5, 1961 UW EEEEEEL INVENTOR ldlalziifilhflhnauz M. 777 CM 777 deem,
HIS ATTORNEYS 'i United States Patent 5 Claims. c1. 219-433 This invention relates to an improved heater for warming formula in nursing bottles and more particularly to a heater for use with nursing bottles of the type that have a disposable inner envelope. This application is a continuation of my co-pending application Serial No. 108,- 048, filed May 5, 1961, now abandoned.
Nursing bottle warmers operating on various heat transfer principles have been known for many years. However, existing nursing bottle warmers have involved somewhat complex structures and have been rather inconvenient to use. These factors have prevented their popular acceptance as a near indispensable accessory for young children during a time when childrens accessories of all kinds have found a welcome market.
Of the known nursing bottle heaters, there are those employing an electrical heating element that vaporizes water which condenses on the bottle and transfers the heat thereto. The heat passes by conduction through the bottle wall and into the infant formula. Other types employ heated air that is circulated around the bottle, While still others have electrical resistance heaters that transfer heat by conduction and convection through a pool of Water to the bottle walls and the contained formula;
To date, none of the existing types of bottle warmers saisfactorily blend the factors of low cost, relatively accurate temperature control, fast heating, and low maintenance requirements, that are necessary to make a really effective and acceptable bottle warmer.
There has recently been introduced a nursing bottle which supports a disposable sterile lining envelope or flexible bag containing the formula. The lining envelope makes sterilization of thebottle unnecessary and more importantly prevents the child from swallowing air bubbles that are always present in ordinary nursing bottles. This new type of nursing bottle introduces a new problem in formula heating, since all prior types of bottle heaters rely on conduction heat transfer through the bottle walls. The lining envelope of the new type bottles creates an interface including small air spaces between the envelope and the internal bottle wall, thus, severely decreasing the conduction heat transfer efficiency of the bottle.
It has thus been an object of my invention to fully investigate the economic and physical problems that are encountered in the provision of a fully acceptable nursing bottle warmer;
Another object of my invention has been to provide an improved nursing bottle warmer that is relatively inexpensive to construct, employs no heat transfer media whatsoever, and canheat an eight-ounce milk-base formula in less than three minutes;
Another important object of my invention has been to provide an improved nursing bottle warmer that will transfer heat uniformly through substantially all surfaces of the bottle to insure maximum fast heating of the formula without endangering the formula integrit such as by curdling;
. A further object of my invention has been to provide animproved nursing bottle warmer that is readily adapt able to a simple control such as an electric timer whereby the bottle warmer will be inexpensive, convenient to use and accurate in its performance;
3,152,245 Patented Oct. 6, 1964 ice A further important object of my invention has been to provide an improved nursing bottle warmer that will heat the formula in bottles having an inner disposable envelope at substantially the same rate and with substantially the same case as bottles of the ordinary type.
These and other important objects of my invention will appear to those skilled in the art upon reading and understanding the following description of my inventive concepts, and an illustrative embodiment thereof.
One phase of my invention involves the use of radiation transferrable' infrared heat that is readily absorbed by the relatively opaque formula, requires no heat transfer media, and passes substantially unchanged through the glass and plastic of which nursing bottles are constructed. Infrared heat sources are inexpensively available in several forms including enclosed reflector bulbs that operate oflf ordinary house voltage. My invention thus eliminates the use of heat-transfer media such as water, steam, and moving air that have interfered with the successful operation of prior bottle warmers by creating problems of control, heat transfer rate, inconvenience, etc. Another factor in using infrared heat in my bottle Warmer is the relatively large amount of heat that can be made rapidly available by effectively eliminating a time delay caused by the presence of a heat transfer fluid iu the path.
Still another factor in bottle warmer performance that results from the use of infrared heat is the relative coolness of the bottle after heating has taken place. All existing bottle Warmers require conduction heat transfer through the bottle to the formula inside, thus necessitating a high temperature gradient across the bottle wall and creating a high bottle wall temperature. As the bottle wall of my invention receives heat only from its contained formulae, it remains at a relatively low temperature, and the bottle is easily handleable immediately when warming is completed.
Another phase of my invention relates to the construction of a reflector that will substantially-uniformly direct infrared heat rays along substantially the entire axis of an elongated tube-like infants formula bottle. It is important that the supplied heat be distributed over as much of the bottles surface as possible in order to minimize heating time or the time required to transfer the necessary number of calories to the milk to bring it up to the desired temperature, without creating localized high temperatures which could cause curdling or otherwise spoil the formula. The frusto-conical reflector terminates at its smaller end in an opening of a size slightly longer than the nursing bottle to be heated, and terminates at its larger end inan opening which is substantially at least as large as the beam from the infrared source, whereby the infrared radiation is most effectively distributed. The reflector of my invention is preferably an upwardly converging truncated cone that is arranged to receive the nursing bottle along its axis. The internal surface of the reflector cone is highly polished to maximize its reflected efficiency and minimize the heat that is absorbed by it. The infrared heat source is positioned below the bottle and the conical reflector, such that only about 40% of the total heat enters the bottle through its bottom and about through its elongated side walls, whereby a substantially uniform heat transfer is maintained through the bottle outer surface.
Another phase of my invention relates to the provision of a safety shield that separates the infrared source from the bottle-containingportion of the warmer. The shield is constructed of a glass material having a low infrared Conveniently, the shield also serves as a support for the nursing bottle in the warmer. An alternative to this form of support however can be had by providing a simple sheet metal support and omitting v.3 the protective shield. Inasmuch as cost plays an important factor in the success of light appliances such as this, the simpler bottle support mechanism may be preferable.
A further phase of my invention relates to the use of a simple mechanical electric timer switch by which the operation of the warmer can be controlled to automatically heat a standard volume of infants formula taken from a refrigerator, to a relatively accurate final temperature. In the past, where heat transfer fluid such as water, steam and air were employed in bottle warmers, variations in the initial temperature of the heat transfer fluid made it substantially impossible to use a simple timing device to control the final temperature of the formula. Complex control methods, such as accurately measuring a small volume of water to be evaporated and condensed during the heating cycle, have been employed to the great inconvenience of the user. As my bottle warmer employs no heat transfer fluid, the simple timer is possible and improved results are attained at a lesser cost.
These phases or inventive concepts of my invention will be more clearly understood upon reading the following disclosure of an illustrative embodiment of my invention, wherein specific reference is made to the accompanying drawings of which:
FIGURE 1 is a cross sectional elevational view of a bottle warmer constructed in accordance with my invention; and
FIGURE 2 is a fragmental vertical cross sectional view of a modified bottle warmer constructed in accordance with my invention.
More specifically, in FIGURE 1, there is shown a heater or bottle warmer having a lower housing or cylindrical casing 11 that is securely connected to a flatsurface-receiving base portion 12. At the upper end of the cylindrical casing 11 is removably secured an upwardly-converging or downwardly-diverging substantially frusto-conical reflector or housing part 13 that terminates at its upper end in a horizontal lip 14 that describes a bottle feeding open portion or bottle warmer mouth 15 of a size slightly larger than the nursing bottle to be heated. The reflector 13 terminates at its larger end in an opening that is at least substantially as large as the infrared beam hereinafter described. As shown both in FIGURES 1 and 2, the axial length of the frusto-conical reflector is at least substantially equal to the length of the bottle side wall and hence will always enclose substantially all of the formula contained in the bottle. The reflector 13 is preferably connected to the casing 11 by a hinge 16 and an opposed sheet metal latch or snap 17. By such construction, it is a simple matter to pivot the reflector to an open position to permit cleaning the internal parts of the bottle warmer. The reflector 13 has an inwardly facing internal surface 13a preferably made of pure anodized aluminum that is polished to a high degree of reflectivity to minimize heat absorption by the reflecting surface 13a.
At the upper end of the cylindrical casing 11 is a support rim or opposed flange means 18 for a supporting protective shield 19 that is constructed of a material such as quartz having a relatively low infrared absorption factor in the frequency range of 1.5 to 5 microns. The protective shield 19 effectively prevents dripping liquid, such as milk or condensed water from damaging the components of the warmer. Conveniently, the protective shield 19 also serves as the support for the nursing bottle within the warmer. Referring to FIGURE 2, an alternative support is shown which comprises a plurality of sheet metal straps 20 that are securely connected to the lip 14 of the reflector portion 13. The support means of FIGURE 2 may be used where the cost of a glass protective shield and its support are prohibitive. Where such support is employed, it is necessary to construct the infrared heat bulb, described below, of a hard glass.
Returning now to FIGURE 1, it will be seen that the cylindrical easing ill encompasses and protects an inexpensive source of infrared heat radiation, such as a reflector type infrared bulb 21 having a diameter greater than the diameter of the bottle to be warmed for directing a beam of infrared radiation upwards from the base 12. The bulb 21 is of relatively low power, being about 375 watts and is currently available as a stock item. The uniform distribution of heat from the peripheral edge portions of the bulb by the reflector l3, maximizes the heat transfer efliciency so as to provide a satisfactorily low heating time even from low wattage heat sources. The bulb 21 is supported by an ordinary screw-type socket 22 and receives house current or other electric energy via electrical conduits 23 and a mechanicalelectrical timer switch 24.
The operation of my bottle warmer is as follows:
A bottle B of formula which may be of conventional construction or of the new, disposable liner construction, as shown in the drawings, is taken from a refrigerator at a known low temperature, and is inserted through the open portion 15 of the reflector 13 into the warmer. The bottle B is supported either by a protective shield 19 as shown in FIGURE 1 or by sheet metal strips 20 as shown in FIGURE 2. The timer is actuated by the user to an empirically determined time that will produce the desired final formula temperature. Once the particular time has been determined for the users refrigerator temperature, a high degree of formulae temperature accuracy is easily attained merely by selecting the proper timer start position. For example, eight ounces of milk-base formula in a standard nursing bottle can be heated from 45 F. to 96 in approximately two minutes and twenty seconds with no danger of scorching the milk or injuring the bottle, if it be of resinous material. This rate of heat supply will be substantially maintained even if bottles are employed that have a disposable inner envelope that effectively prevents the use of conventional bottle warming devices.
It will be appreciated that I have provided an improved bottle warmer that employs relatively simple structural features to attain a rapid and safe warming of a nursing bottle without the use of heat transfer fluid. It will also be appreciated that I have provided a bottle warmer that operates as efliciently with conventional bottles as with bottles of the type having a disposable inner envelope.
Having thus described the concepts of my invention and an illustrative embodiment thereof, I claim:
1. A warmer for heating the contents of nursing botties of the type having elongated infrared transparent side walls, an infrared transparent bottom wall, and an upper nipple mounting portion; said warmer comprising: a base, a source of infrared heat radiation mounted on said base for directing a beam of infrared radiation upwardly therefrom, a substantially frusto-conical housing part having a highly polished inwardly facing surface, said frusto-conical housing part terminating at its smaller end in an opening of a size slightly larger than the nursing bottle to be heated and terminating at its larger end in an opening that is substantially at least as large as said beam, said frusto-conical housing part having an axial length at least substantially equal to the length of the bottle side walls, means connected to said base and to said housing part for supporting said housing part in a downwardly divergent orientation above said source, and bottle support means operatively connected to said base and positioned within said frusto-conical housing part for supporting the bottle with a substantial portion of the axial length of its side walls within said frustoconical housing part.
2. A warmer as defined in claim 1 wherein said bottle support means comprises an infrared-transparent plate that protectively separates said infrared source from the bottle containing portion of the warmer.
3. A warmer as defined in claim 1 further comprising timer means for controlling the time of operation of heat source in accordance with a pre-set time interval.
4. A warmer as defined in claim 1 wherein the bottle support means comprises a plurality of fingers that are connected to said frust0-conical housing part and extend downwardly therewithin to supportingly receive the nurs ing bottle.
5. A warmer for heating the contents of nursing bot tles of the type having elongated infrared transparent side walls, an infrared transparent bottom wall, and an upper nipple mounting portion; said warmer comprising: a base, a source of infrared heat radiation mounted on said base for directing a beam of infrared radiation upwardly therefrom, a substantially frusto-conical housing part having a highly polished inwardly facing surface, said frusto-conical housing part terminating at its smaller end in an opening of a size slightly larger than the nursing bottle to be heated and terminating at its larger end in an opening that is substantially at least as large as said beam, said frusto-conical housing part having an axial length at least substantially equal to the length of the bottle side Wall, a circumferentially continuous, vertically upwardly extending casing mounted on said base and en closing said source of infrared heat radiation, said frustoconical housing part being supportingly mounted on the upper end of said casing in a downwardly divergent orientation above said source, and bottle support means operatively connected to said base and positioned within said frusto-conical housing part for supporting the bottle with a substantial portion of the axial length of its side walls within said frusto-conical housing part.
References Cited in the file of this patent UNITED STATES PATENTS