US3617698A

US3617698A - Vaporizer apparatus

Info

Publication number: US3617698A
Application number: US10451A
Authority: US
Inventors: Robert H Duncanson
Original assignee: Faberge Inc
Current assignee: Faberge Inc
Priority date: 1970-02-11
Filing date: 1970-02-11
Publication date: 1971-11-02
Anticipated expiration: 1988-11-02
Also published as: BE762811A; IE34940B1; SE364106B; NO130080B; IE34940L; ZA71806B; FR2078477A5; CH522182A

Abstract

An electrical heater for liquids, particularly an electrode plate water vaporizer, is proofed against electrical shock hazard by insuring that current paths through the liquid into possible contact with the user are elongated, discontinuous, and on filling when the hazard is greatest, are completely interrupted to assure safety even under negligent handling.

Description

United States Patent References Cited UNITED STATES PATENTS Pentz Goodfellow Goodfellow McCloud Lindgren White Blair Black Luse, Jr. et al Primary Examiner-J. V. Truhe Assistant Examiner-G. R. Peterson Attorney- Davis, Hoxie, Faithful1& l-lapgood ABSTRACT: An electrical heater for liquids, particularly an electrode plate water vaporizer, is proofed against electrical shock hazard by insuring that current paths through the liquid into possible contact with the user are elongated, discontinuous, and on filling when the hazard is greatest, are completely interrupted to assure safety even under negligent handling.

PATENTEDHUV 2 ISTI II III/III I III I III] I A I I I l I I I I I I II mum/0r Robe/H Mum 0/1500 By 00 W5, HOME, Fa/fh/ufl 8 Hapgooo' A from eys Y vAronlzait APPARATUS This application is a continuation-in-part of my copending application Ser. No. 706,809, filed Feb. 20, 1968, entitled Apparatus for Applying Air and Vapor to the Face and Hair, now U.S. list. No. 3,495,343.

The present invention is. concerned with apparatus for generating vapor for such use as a humidifier or vaporizer by raising the temperature of a liquid such as water or water with added medicaments or the like. The temperature of the liquid is raised by electrical means such as an electrical resistance element or by immersed electrode plates.

Of primary concern in electrically operated vaporizer devices is electrical shock hazard due to the fact that the liquid to be vaporized is usually somewhat electrically conductive and may be in direct electrical contact with the electrical power line. This hazard is greater with immersed electrode plate devices than with resistance element devices because the latter are usually electrically insulated from direct contact with the liquid; however, in a moist environment the effectiveness of the insulation is reduced and commonly allows enough electrical current flow to the liquid to'become objectionable. Immersed electrode plate devices require direct contact between the liquid and the power line. The hazard is further aggravated at the higher domestic voltages common in countries foreign to the United States. The hazard is further aggravated by the fact that the most common liquid employed is water and users may be tempted to till the device from electrically grounded water taps while the device is connected to the power line. Further, the shock hazard with such devices may be greater when the user's skin is wet.

The vaporizer of the present invention virtually eliminates the potential shock hazard by maintaining that under all conditions of use and misuse a high resistance path between the electrodes and the user, preventing the user from contacting the liquid in the electrode chamber, and by eliminating any electrical shock consequence from overfilling or tilting of the unit.

In the drawings:

FIG. 1 is an elevational view in section of an embodiment of a vaporizer constructed in accordance with this invention;

FlG. 2 is a top view of the vaporizer of FIG. 1;

FIG. 3 is a view partly in section taken from the plane 3-3 ofFlG.1;and a FIG. 4 is a view similar to FIG. 1 showing how an attempted erroneous filling through the vapor exit port is harmlessly discharged.

Referring now to FIGS. 1-3, the apparatus is shown in a preferred embodiment which is in .the form of a room vaporizer for humidifying room air or dispensing medicated vapors for sick room use. The apparatus comprises a housing including a filling receptacle l2 and .a vapor exit port 16. Within the housing 10 is a boiler chamber which can be filled with the liquid to be vaporized. vaporization is accomplished within the boiler by the well-known technique of passing electrical current through a portion of the liquid between a pair of spaced-

electrode plates

22, 23 which differ in electrical potential by being connected to the house power line. The vapor generated by the electrodes collects above the liquid in the boiler chamber 20 and issues from the top wall of the boiler chamber through an opening 24 which is in communication with the vapor exit port 16 of the housing 10. A baffle member 27 helps direct the vapor toward the exit port 16. Liquid to be vaporized is conveyed to the boiler chamber by means of an inclined ramp, channel, or conduit 26 which leads from a point directly below the filling receptacle 12 of the housing to the opening 24 in the top of the boiler chamber.

Because the liquid to be vaporized is in direct contact with the

electrodes

22, 23 which are at a potential determined by the electrical power line, it is necessary to isolate the user from direct or indirect contact with the liquid in the boiler chamber. This is accomplished by providing very long paths for leakage current from the boiler chamber to the exterior of the housing; by interrupting, elongating, and reducing the conductive cross-sectional area of the stream of liquid during filling; by insuring that the electrodes are not immersed when the unit is tilted into a draining attitude; and by excluding fingers or probing instrumentalities from entry or contact with the liquid.

When the surfaces of an electrical device are wet with an uninterrupted film of water or other conductive liquid, a conductive path may be established between a user in contact with the device and the power line resulting in risk of electrical shock. The current and voltage depend inversely upon the resistance of the film. This resistance is increased by increasing the length of the conductive path. Referring to FIGS. 14, the construction of the present device provides only extremely long and consequently high-resistance paths between a user touching the outside of the housing and the electrodes on the inside of the enclosed boiler. The boiler chamber 20 is of nonconductive material such as plastic. The boiler chamber 20 is completely enclosed within the housing 10 which is also a nonconductor. The boiler chamber 20 is spaced away from the interior of housing 10 by means of long narrow supporting posts 14. This construction results in a very long path between the exterior of the housing 10 and the electrodes on the interior of the boiler chamber 20. All surfaces which may be wetted with condensed vapor are remote from the electrodes. Further, the elongated current leakage paths are discontinuous because the numerous sharp corners in the path substantially reduce the possibility of maintaining an uninterrupted surface film of liquid. The filmbreaking effect of sharp comers is augmented by the use of film-breaking sharp edges 21 which discourage the maintenance of a continuous film current path to the posts 14. Any conductive path between the electrodes and the housing exterior must traverse the long narrow support posts 14 which are remote from any exterior surface. The result of the foregoing characteristics is a low probability for an uninterrupted wet surface film conductive path and a film path resistance in the order of hundreds of thousands of ohms, which is adequate to reduce the current to a harmless level.

To prevent the establishment of a conductive path from the electrodes through the body of the user should the user fill the device while it is connected to the power line, the stream of filling liquid is interrupted and is reduced in cross-sectional area. The filling liquid is poured into the funnel-shaped filling receptacle 12. The liquid flows by gravity through one or more small apertures 13 in the bottom of the receptacle. The size of apertures 13 is chosen to limit the liquid flow to promote the formation of discrete drops rather than a continuous stream. The number of such drop forming apertures is chosen to insure rapid filling. The formation of drops interrupts a conductive path. The drops impinge upon an inclined ramp or channel 26 which conveys the liquid to the opening 24 in the top wall of the boiler chamber 20. The slope of the ramp accelerates the liquid so as to form a relatively thin film of moving liquid thereby presenting a minimal cross-sectional area of liquid for high resistance to current flow. Upon reaching the opening 24, the film of liquid is again broken up into discrete drops which interrupt any conductive path. The drops fall into the boiler chamber.

Shock hazard risk in the event of overlilling the boiler is reduced by insuring that the conductive path between the

electrodes

22, 23 and the drain holes 15 is long and of consequent high resistance. Liquid in excess of the intended capacity of the boiler chamber 20 spills from the vicinity of boiler opening 24 into the space between the boiler chamber 20 and the interior of the housing 10. Opening 24 is at a lower elevation than the top wall of the boiler chamber to form an air lock to entrap a pocket of air to preserve a vapor space in the chamber in the event of an attempt to overfill. From there it drains out through drain holes 15. Drain holes 15 are located as far from support posts 14 as is practical to lengthen the path for current between the

electrodes

22, 23 and the liquid which may spill from drain holes 15.

FIG. 4 shows the vaporizer of the present invention in a tilted position which might be employed to drain the boiler chamber after use of the device. In any position, including completely inverted, where liquid can run out from the boiler chamber, the electrodes are in a position where they are no longer immersed. This interrupts any conductive path from the electrodes to the draining liquid.

FIG. 4 also illustrates the futility of an attempt to erroneously fill the boiler chamber through the vapor exit port 16 rather than through the intended filling receptacle 12. The liquid simply spills harmlessly into the space between the boiler chamber and the housing from which it drains through the drain holes 15. The erroneously introduced liquid is kept remote from contact with the electrodes.

Fingers and probing instrumentalities are excluded from the boiler chamber by providing opening 245 as the only access to the interior of the boiler and by locating opening 24 in a position out of alignment with either of the exit port 16 or the filling receptacle 12. Further exclusion is provided by covering the vapor exit port 16 with a screen or apertured grid structure 17 with relatively small apertures.

The double shell construction of the present device wherein the boiler chamber is spaced from the housing maintains the exterior of the housing at a comfortably cool temperature while the liquid in the boiler is heated to boiling.

Although the present invention has been described and illustrated with reference to a particular room vaporizer as the preferred embodiment, it is apparent that the invention can be incorporated into various electrical liquid heating devices such as central heating system humidifiers, food an bottle warmers, sauna devices, etc. My aforementioned copending application Ser. No. 706,809describes and illustrates incorporation of this invention into a hair drying apparatus.

I claim:

l. A water heater having a container and spaced electrodes in the container for heating water by passing current from one electrode to the other through the water and in which means for filling the container are provided comprising a conduit having a downwardly sloping floor with an upper inlet end and terminating in a lower discharge end disposed over an entrance to the container remote from the electrodes, a filling receptacle having a drop forming exit orifice positioned above the inlet end of the conduit, the arrangement being such that water introduced to the filling receptacle will flow from its orifice in drops which fall to the inlet end of the conduit and thence downwardly to fall from the discharge end of the conduit into the container, whereby discontinuity is imparted to the flow of water to enchance its resistance to the passage of electrical current therethrough.

2. The water heater as defined in claim 1 in which the downward slope of the floor of the conduit accelerates the velocity of flow of water to thereby reduce its average crosssectional area to increase its electrical resistance.

3. A heater for liquids comprising a nonconductive outer housing, a nonconductive liquid heating chamber having a top wall and including an electrical heater means, said heating chamber being enclosed within the outer housing, said heating chamber being spaced away from the interior surfaces of the outer housing by means of elongated electrically nonconductive support members, a filling receptacle for receiving liquid to be conveyed to the heating chamber, said filling receptacle having a drop forming exit orifice, and conduit means leading from a position below the exit orifice to an entrance to the heating chamber, whereby a stream of filling liquid is discontinuous to interrupt a flow of electrical current therethrough.

4. The heater of claim 3 wherein the conduit is inclined to increase the velocity of the flowing liquid to decrease its crosssectional area and thereby increase its electrical resistance.

5. The heater of claim 3 wherein the conduit terminates in a position above the entrance to the heating chamber to cause the liquid to fall from that end of the conduit into the heating chamber in the form of drops to further interrupt the flow of electrical current therethrough.

6. The heater of claim 3 wherein the entrance to the heating chamber is located at an elevation lower than the top wall of the heatin chamber to form within the chamber an air lock whereby t e heating chamber cannot be completely filled with liquid to preserve a vapor space above the liquid within the heating chamber.

7. The heater of claim 6 wherein the outer housing includes drain holes to discharge liquid which may appear in the space between the heating chamber and the interior of the outer housing and wherein such drain holes are located remote from the support members to maximize the length of a conductive path and its resistance to current flow to the exterior of the outer housing.

8. The heater of claim 6 wherein the heating chamber is provided with sharp edges and corners to render discontinuous a film of liquid on its outer surface.

9. A water vaporizer comprising a nonconductive heating chamber including an electrode plate water-heating means and a top wall, and a nonconductive outer housing including a vapor exit port and a water filling receptacle, the heating chamber being spaced away from the interior surface of the outer housing by elongated support members, the heating chamber having an opening in its top wall for filling and for discharge of vapor, the vapor exit port being in communication with said opening, the water-filling receptacle including a drop forming exit orifice, and an inclined channel means for conveying filling water downwardly from a position below the drop forming orifice to said opening whereby the steam of filling water is discontinuous to interrupt the flow of electrical current therethrough.

10. The vaporizer of claim 9 wherein the heating chamber is provided with sharp edges to interrupt a surface film of water.

11. The vaporizer of claim 9 wherein said opening is at an elevation below the maximum interior elevation of the heating chamber to thereby preserve a vapor space above the liquid in the chamber.

12. The vaporizer of claim 9 wherein said opening is at the end of the heating chamber remote from the electrode plate heating means whereby said heating means are not immersed when the vaporizer is tipped to drain liquid from the heating chamber through said opening.

13. The vaporizer of claim 9 wherein the vapor exit port and said opening are not in alignment to exclude instrumentalities from contact with the water in the heating chamber.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,617,698 Dated November 2, 1971 I t Robert H. Duncanson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 23, cancel "further". Column 4, line 41,

"steam" should read stream Signed and sealed this 29th day of August 1972.

(SEAL) Attest EDWARD M. FLETCHER,JR. ROBERT GOTTSCHALK Commissioner of Patents Attesting Officer FORM PO-1050 (10-69) uscoMM-Dc 60376-P69 U 5V GOVERNMENT PRINTING OFFICE 1969 0-355-334

Claims

1. A water heater having a container and spaced electrodes in the container for heating water by passing current from one electrode to the other through the water and in which means for filling the container are provided comprising a conduit having a downwardly sloping floor with an upper inlet end and terminating in a lower discharge end disposed over an entrance to the container remote frOm the electrodes, a filling receptacle having a drop forming exit orifice positioned above the inlet end of the conduit, the arrangement being such that water introduced to the filling receptacle will flow from its orifice in drops which fall to the inlet end of the conduit and thence downwardly to fall from the discharge end of the conduit into the container, whereby discontinuity is imparted to the flow of water to enchance its resistance to the passage of electrical current therethrough.

2. The water heater as defined in claim 1 in which the downward slope of the floor of the conduit accelerates the velocity of flow of water to thereby reduce its average cross-sectional area to increase its electrical resistance.

4. The heater of claim 3 wherein the conduit is inclined to increase the velocity of the flowing liquid to decrease its cross-sectional area and thereby increase its electrical resistance.

6. The heater of claim 3 wherein the entrance to the heating chamber is located at an elevation lower than the top wall of the heating chamber to form within the chamber an air lock whereby the heating chamber cannot be completely filled with liquid to preserve a vapor space above the liquid within the heating chamber.