US1913442A - Liquid conductor heater - Google Patents

Description

June 13, 1933. M. w. HANKS 1,913,442

LIQUID CONDUCTOR HEATER Filed Feb. 2'7, 1930 mum-w IIIIIIII u- 18 H 1 \fij j Patented June 13, 1933 PATENT OFFICE MARSHALL W. BANKS, OF MADISON, WISCONSIN LIQUID CONDUCTOR HEATER Application filed February 27, 1930. Serial No. 431,711.

This invention relates to improvements in liquid conductor heaters in which heat is generated by the passage of an electric current through a body of liquid in which fi' spaced electrodes are partially or wholly submerged. Heaters of this type are described and claimed in several of my prior patents and, for illustration, in the United States patent to Marshall W. Hanks and Max Mason No. 1,683,071 granted September 4, 1928.

Liquid conductor heaters may be advantageously employed for heating or cooking various articles or commodities such as eggs or other food products, the sterilization of instruments, and other uses. For most purposes, it is desirable that a measured quantity of liquid be placed in the vessel containing the electrodes between which the current passes so that the apparatus has a definite time period of operation determined by the time required to effect a complete evaporation of the liquid and a consequent shut-off of the current flow. Since many liquid conductor heaters, particularly those employed for heating and cooking purposes in the household, are commonly operated by persons who are not highly skilled in the operation of electric apparatus, it is desirable so that such forms of apparatus be so constructed as to protect the operator, as far as possible, from the danger of shock by reason of contact of the fingers or other parts ofthe body with the electrodes or the liquid through which the current passes.

The principal object of the invention is -to provide the vessel, which contains the spaced electrodes and in which the liquid conductor is adapted to be contained, with an insulating device which prevents the hands of the operator from coming accidentally into contact with the electrodes or with the liquid conductor by which they are connected. A further object is to provide the vessel of a liquid conductor heater with an insulating partition by which the chamber is divided into an electrode containing chamber and another chamber adapted to contain the object or objects to be heated. Another object of the invention is to provide a liquid conductor heater comprising a vessel containing spaced electrodes and having mounted therein an insulating device which not only prevents contact of the operator with these electrodes but also serves as a support for the oblect to be heated or cooked. A further object is to provide the vessel of a liquid conductor heater with a removable insulating tray which is perforated to permit the escape of vapor from the space occupied by the electrodes but which prevents accidental contact of the hands of the operator with the electrodes. Other objects relate to various features of construction and arrangement which will appear more fully hereinafter.

The nature of the invention will be understood from the following specification taken with the accompanying drawing, in which two embodiments are illustrated. In the drawing,

Fig. 1 shows a central vertical section taken through a liquid conductor heater embodying the features of the present invention and adapted particularly for use in cooking eggs;

Fig. 2 shows a horizontal section taken on the line 22 of Fig. 1;

Fig. 3 shows a top plan view of the base of thei1 heater with the cover and eggs removed; an

Fig. 4 shows a central vertical section through a modified form of construction adapted for use, for example, in heating a babys milk bottle.

The form of the invention shown in Figs. 1, 2 and '3 comprises a vessel 10 formed of porcelain or other suitable insulating material and having a downwardly and outwardly flared base flange 11 which is adapted to rest upon a table or other support 12. Mounted in the lower part of the vessel 10 is an electrode 13 in the form of an annular metal ring seated on the bottom of the vessel around a central upwardly extending projection 14 formed integrally with the bottom of the vessel. A pair of threaded posts 15 are secured to the under side of the electrode 13 and extend downwardly through apertures in the bottom wall of the vessel, being engaged at their lower ends by nuts '15. These posts are adapted to have a fluid-tight connection with the apertures through which they pass in order to prevent the escape of fluid from the interior of the vessel. Mounted centrally in the bottom of the vessel and extending upwardly through the projection 14 is a threaded post 16 which has a threaded connection at its upper end with the central hub portion 17 of another electrode 17 This electrode is provided with a plurality of perforations 1,7 which are distributed over its surface, as shown in Fig. 2, and it is spaced upwardly from the lower electrode 13 with the outer edge thereof engaging an annular shoulder 18 formed on the inner wall of the vessel 10. The threaded post 16 has a threaded extension 19 of reduced diameter which is engaged at its lower end by a threaded nut 19? of insulating material. An electric conductor 20 is connected to one of the posts 15 beneath one of the nuts 15 and another conductor 21, leading from the other side of the circuit, is electrically connected to the mem-. ber 19 by means of a nut 22 which threadedly engages the member 19 beneath the bottom of the vessel. The conductors 20 and 21 have a common insulating covering 23 and are extended outwardly through an aperture 24 in the base flange 11. A cover plate 25 is seated against an annular shoulder 26 formed on the base flange 11 and is held in place by the engagement thereof with the reduced upper portion of the insulating nut 19 thus enclosing the terminal posts and electrical conductors in the chamber which is thus formed within the base flange.

lVhen a liquid conductor, such as water, is placed in the vessel 10, a connection is thereby established between the spaced electrodes 13 and 17 so that the current flowing through the liquid vaporizes it and causes the vapor to pass upwardly to heat any object which may be placed in the chamber formed by the upper part of the vessel 10 and the complementary dome-shaped cover 30, which may be formed of metal or insulated material and arranged to have its lower edge seat upon the shoulder 31 around the upper edge of the vessel within the annular shoulder 32 formed thereon. The cover 30 is preferably provided with one or more apertures 23 which permit the escape of steam or vapor from the heating chamber and the upper part of the cover may be provided with a measuring vessel 35 formed of porcelain, bakelite, or other insulating material, so that it may serve also as a handle for the cover. The chamber 35 of this measuring vessel is adapted to receive a-measurcd quantity of liquid and this measured quantity of liquid flows gradually downward through the reduced opening 36 to the lower part of the vessel 10 where it establishes the connection between the electrodes,

as referred to above. By the use of this measuring chamber having a restricted outlet, the liquid is gradually supplied to the vessel so that a rapid rise of current, when the apparatus is started in operation, is prevented, as more'fully set forth and claimed in my prior lgatent No. 1,683,070, dated September 4, 1'. 28.

The vessel 10 is provided some distance above the upper electrode 17 with an annular shoulder 37 which serves as a support for a removable tray 38 formed of insulating material such as porcelain, molded bakelite, and the like. This tray, which may be concave or convex to facilitate drainage, is adapted to fit the cylindrical wall 39 which extends upwardly from the shoulder 37 which may be formed as a series of projecting lugs, and it is provided with a number of apertures 40 through which the steam or vapor may escape from the chamber 41 immediately above the electrodes to the heating chamber 42 formed by the upper part of the vessel 10 and the cover 30, within which the object or things to be heated are placed. The tray 38, which thus serves as a partition to divide the space within the vessel into two separate chambers, also serves preferably as a support for the eggs 43 or other objects to be heated and for this purpose the tray has formed integrally therewith a plurality of downwardly concave receptacles 44 which are adapted to engage the lower ends of the eggs. This partition or tray 38, in addition to providing a support for the eggs, serves as an insulating device to prevent accidental contactofthe fingers of the operator with the electrode 17 or with the damp walls of the chamber 41 and thereby eliminates the danger of shock. The apertures 40 through this partition or tray are of such small size that the fingers cannot be inserted therethrough and although the tray may be intentionally removed, its engagement with the annular' shoulder 37 and substantially close fit within the cylindrical wall 39 will prevent its accidental removal. During the operation of the device, the liquid is vaporized by the passage of the current and the resulting vapor passes upwardly through the passages 40 to heat and cook the eggs 43 in the heating chamber 42. This operation continues until the liquid is entirely vaporized, when the special form of electrodes herein illustrated are adapted to effect a rapid shut-oil of the current flow, as described and claimed in the prior Patent No. 1,683,069.

In the embodiment illustrated in Figs. 1, 2 and 3, the principal electrode 17 has a screwthreaded engagement with the post 16 and, if desired, the tray 38 may be provided with legs 45, as shown by dotted lines in Fi 1, for connecting it with the upper electr e so that the tray can be removed only by a rotative movement which will simultaneously remove the upper electrode from its engagement with the post 16. The upper electrode 17, whether it is connected to the tray 38 or Inn III

not, referably contacts with the annular shoul er 18 on the vessel 10 when it is-in its lower position, a feature which is adapted to eliminate or greatly reduce the danger of shock through contact with the dam walls of the vessel, as described and claim in my co-pending application Serial No. 431,712, filed February 27, 1930.

In Fig. 4 of the drawing, there is illustrated somewhat diagrammatically a modified form of the invention. This modified form comprises a vessel formed of porcelain or other suitable insulating material which has an outwardly flared annular base flange 51 adapted to rest upon a support. One plate electrode 52 is mounted on the bottom of the vessel and is connected to a conductor 53 leading upwardly through the bottom wall. I Another plate electrode 54 is spaced upwardly from the electrode 52 and connected to another conductor 55 forming the other side of the electric circuit and also extending upwardly through the base of the vessel. Seated directly on the upper electrode 54, which may be supported by a central insulating post 56 or by other means, is an insulating tray or plate 57 havinglegs 58 which rest directly upon the upper electrode. This tray serves as a partition to prevent accidental contactvwith the upper electrode with the hands of the operator and it is curved to conform to,the curvature of the bottom of a babys milk bottle 58, for

35 example, which is placed thereon and which is adapted to be heated by the vapor passing upwardly from the region between the gl7ectrodes around the outer edges of the tray 0 Although two forms of the invention have been shown and described by way of illustration, it will be understood that it may be constructed in various other embodiments within the scope of the appended claim. 5 I claim:

A liquid conductor heater comprising a vessel adapted to contain a liquid conductor, a pair of spaced electrodes mounted in the lower part of said vessel to be connected by 50 said liquid conductor, and an insulating partition extending across said vessel above said electrodes and having formed therein a plurality of downwardly concaved perforated receptacles adapted to conform to portions of $8 the articles to be heated.

In testimony whereof, I have subscribed my name.

MARSHALL W. HANKS.

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