Method and apparatus for heating a fluid

• US 4,308,636 A
• Filed: 09/25/1978
• Issued: 01/05/1982
• Est. Priority Date: 06/23/1977
• Status: Expired due to Term

• Current Assignee: Southwest Transheater Corporation
• Original Assignee: John W. Davis
• Inventors: Davis, John W.
• Primary Examiner(s): Moore, Christopher K.
• Application Number:
  US06/945,450
• Time in Patent Office: 1,198 Days
• Field of Search: 15/321, 219/10.51, 219/300
• US Class Current: 15/321
• CPC Class Codes: A47L 11/34 Machines for treating carpets in position by liquid, foam, or vapour, e.g. by steam
• CPC Class Codes: A47L 11/4086 Arrangements for steam generation
• CPC Class Codes: A47L 11/4088 Supply pumps; Spraying devices; Supply conduits
• CPC Class Codes: H05B 6/108 for heating a fluid

Abstract

Method and apparatus for heating a fluid, such as water, for any of several purposes, such as for use with carpet cleaning apparatus; and charcterized by supplying electrical current periodically to the primary of a conductive coil, thereby building and collapsing a field about a shorted electrically conductive secondary of the coil. The shorted secondary is a hollow conductor that is heated by high current flow. The heat is transferred to a fluid flowing through the hot, shorted secondary. In a specific aspect of the embodiment, a frame including spray nozzles, vacuum nozzles and the like has the apparatus for heating water connected into it such that heated water is supplied, to effect much more efficacious cleaning of carpets or similar floor surfaces. Also disclosed are specific details and preferred embodiments that have been constructed to date; particularly, the details of the apparatus in which the primary and the secondary coils are closely adjacent each other such that the I² R heating that occurs in both the primary and secondary due to the building and collapsing of the field contribute to heating of the fluid passed through the fluid passageway in the secondary with the primary and secondary overwound on the same leg of the core, more of the flux that builds and collapses passes through both the primary and secondary so there is more heating of the fluid passing through the secondary. The hollow conductor of the secondary is deliberately shorted with a continuous weld so that there are an infinite number of elemental shorting bars whose I² R losses produce greater heating of the fluid passed through the secondary.

Claims

1. Apparatus for cleaning floor surfaces, especially carpet, comprising:

a. a frame having a handle extending upwardly therefrom for facilitating movement of said frame about said floor surface;

b. a plurality of fluid nozzles carried by said frame in at least one row parallel to said floor surface and operational to spray fluid toward the floor surface;

c. heating means connected with and upstream of said fluid nozzles for heating the fluid flowed therethrough;

said heating means being located within said frame and close to said fluid nozzles so as to have minimal heat loss;

said heating means consisting essentially of primary and secondary coils disposed in annular concentric relationship with respect to each other and adjacent and in concentric relationship with respect to a core;

i. said primary coil having many more turns than said secondary coil such that said electromagnetic field efficiently builds and collapses through both said primary and secondary coils and introduces a much higher current flow in said secondary coil than in said primary coil;

said primary coil having means for connecting with a source of current capable of effecting building and collaspsing of an electromagnetic field in said primary coil, and in said closely disposed secondary coil, and

ii. said shorted secondary coil comprising an electrical conductor in the form of an electrically conductive sheath adapted for conducting high current and having at least one fluid passageway defined therewithin for flowing said fluid adjacent said electrical conductor for transferring heat from said electrical conductor to said fluid for heating said fluid rapidly;

said shorted secondary coil being shorted continuously within the length and breadth dimensions of said coil and said electromagnetic field so as to have lower resistance and higher current flows, and on infinite number of I² R heat generators resulting in its higher heating and greater efficiency than if shorted exteriorly of said secondary coil;

said primary coil and said shorted secondary coil being closely disposed adjacent each other such that substantially all of the flux of said electromagnetic field builds and collapses through both said primary and said secondary coils with resultant great efficiency in inducing electrical current to flow in and heat said shorted secondary coil and the fluid flowing therethrough, such that the I² R heating occurs in both primary and secondary coils and contributes to heating the fluid flowing through said passageway in said shorted secondary coil;

d. a vacuum nozzle carried by said frame and positioned adjacent the floor surface opposite said fluid nozzles for extracting the heated fluid, dirt and the like from said floor surface;

e. conduit means in fluid communication with said fluid nozzles and heating means for supplying pressurized fluid thereto; and

f. means for supplying fluid under pressure to said conduit means.

2. The apparatus of claim 1 wherein an automatic control means is provided for automatically controlling the flow of electrical current to said primary coil so as to control the temperature in the shorted secondary and the fluid flowing therethrough.

3. The apparatus of claim 1 wherein said primary coil has means for connection with an alternating current power source wherein said fluid passage makes a plurality of traverses through said shorted secondary for efficient transfer of heat to said fluid to achieve the desired hot fluid at the fluid nozzles without melting said secondary coil.

4. The apparatus of claim 1 wherein said shorted secondary coil comprises a coil of metallic tubing that is electrically conductive, connected together laterally so as to effect fewer turns of conductor than said primary coil, and to effect shorting of said secondary within the dimensions of said secondary coil and arranged for conducting water therethrough;

said coil of metallic tubing and said primary coil being concentric.

5. The apparatus of claim 1 wherein said primary and said secondary coils are symmetrical about a common point in both axial and radial directions;

two rows of nozzles are employed, a first row being for washing;

means are provided for adding a cleaning solution to the hot water being sprayed out said first row of coils for washing the fibers of said carpet;

a second row being for rinsing;

means for switching said hot water to the rinse cycle and eliminating the cleaning solution from the hot rinse water.

6. Apparatus for heating fluid comprising:

a. a primary coil having means for connection with a source of current capable of effecting building and collapsing of an electromagnetic field in said primary coil; and

b. a shorted secondary coil comprising an electrical conductor in the form of an electrically conductive sheath adapted for conducting high current ahd having at least one fluid passageway defined therewithin for flowing the fluid adjacent said electrical conductor for transferring heat from said electrical conductor to said fluid for heating said fluid rapidly;

said shorted secondary coil being shorted continuously within the dimensions of said coil so as to have lower resistance and higher current flow and, hence, higher heating and greater efficiency than if shorted exteriorly of said secondary coil;

said primary coil and said shorted secondary coil being disposed closely adjacent and contiguous each other, without intervening impedance increasing chambers in between, and in annular concentric relationship with respect to each other, adjacent and in concentric relationship with a core for concentrating an electromagnetic field such that substantially all of the flux of said electromagnetic field builds and collapses about both with resultant great efficiency in inducing electrical current to flow in and heat said shorted secondary coil, such that the increased I² R heating occurs in both primary and secondary coils and contributes to heating the fluid flowed in said passageway in said shorted secondary coil;

said primary coil having many more turns than said secondary coil such that said electromagnetic field efficiently builds and collapses through both said primary and secondary coil and introduces a much higher current flow in said secondary secondary coil than in said primary coil;

said primary coil and said shorted secondary coil being symmetrical about a common point in both axial and radial directions.

7. The apparatus of claim 6 wherein there is provided an automatic control for automatically controlling the current to said primary coil for controlling the temperature in said shorted secondary coil and said fluid flowing therethrough;

wherein said primary coil has means for connecting with an alternating current power source and wherein said fluid passageway makes a plurality of traverses through said shorted secondary for efficient transfer of heat to said fluid to achieve the desired hot fluid at the effluent of said shorted secondary coil.

8. The apparatus of claim 6 wherein said shorted secondary coil comprises a coil of metallic tubing that is electrically conductive, connected together laterally by an electrically conductive bond comprising a small amount of silver solder throughout the traverse of the turns of said secondary coil for decreased resistance and increased current flow without wasting heat heating a large mass of metal, as well as increased number of elemental shorting shunts intermediate the respective coils for increased heating and so as to effect fewer turns than said primary coil and to effect the shorting within the dimensions of the secondary coil and the electromagnetic field, and arranged for conducting said fluid therethrough.

9. A method of heating fluid comprising the steps of:

a. arranging a primary coil and a secondary coil closely adjacent and contiguous each other, without intervening impedance increasing chamber inbetween, and in annular concentric relationship with respect to each other, closely adjacent and about a soft iron core such that an electromagnetic field will build and collapse about both said primary and secondary coils with great efficiency in inducing electrical current to flow in and heat said secondary coil;

forming said secondary coil in the form of a continuous electrically conductive sheath adapted for conducting high current and having at least one fluid passageway defined therewithin for flowing of fluid adjacent the electrically conductive sheath for transferring heat rapidly from said sheath to said fluid;

forming said sheath by silver soldering respective coils of tubing together laterally with only a small mass of silver solder so as to form a low resistance completed electrical circuit within the shorted secondary coil such that said secondary coil is effectively electrically shorted continuously interiorly of its dimensions for achieving high current flow therein;

forming said secondary coil closely adjacent said primary coil such that the I² R heating that takes place in both said primary and secondary coils contribute to heating of fluid flowing through said secondary coil;

b. supplying to said electrically conductive primary coil an electrical current that effects building and collapsing of an electromagnetic field; and

c. simutaneously flowing said fluid to be heated through said fluid passageway in said conductive sheath of said secondary coil so as to flow in heat exchange relationship with the shorted secondary and effect transfer of heat from the shorted secondary to said fluid.