US3617699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A system for electrically heating a fluid being transported in a pipe
Assignee: Individual
•
Filing: 1969-03-10
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Granted: 1971-11-02
•
Expires: 1989-03-10
Abstract
Abstract A system for heating a fluid being transported in a pipe includes a ferromagnetic heat-tube coextensive with a section of pipe to be heated. The heat-tube is secured in heat exchange relation to the pipe and has a substantial part of its wall in common with the wall of the pipe. An insulated conductor is disposed within the tube. One end of the conductor is electrically connected to one terminal of an AC source and the other end thereof is electrically connected to an end of the tube. The other end of the tube is electrically connected to the other terminal of the AC source. When alternating current flows through the circuit thus established, it passes only the inner surface of the tube due to the skin effect of the alternating current, thereby generating heat on the inner surface of the tube without current appearing on the outer surface thereof. The heattube can be formed by welding a concave strip to the outer cylinder surface of the pipe with the conductor disposed therebetween. Alternatively, the heat-tube can be integrally formed with the pipe as one channel of a two-channel pipe, the other channel being used to transport the fluid. The heat-tube may be helically wound around pipe. The heat-tube is either evacuated or pressurized and means to detect pressure changes indicative of heat-tube leakage is provided.
Inventors
- 👤 Donald F Othmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:29
CPC Classifications
F; F24; F24H; F24H1/00; F24H1/10; F24H1/12; F24H1/121; F16; F16L; F16L53/00; F16L53/30; F16L53/34; F24H9/00; F24H9/40; F24H9/45; F24H9/455; Y; Y10; Y10T; Y10T137/00; Y10T137/6416; Y10T137/6606
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
293 words
In the system for heating a fluid being transported in a pipe comprising: a. a fluid transport-pipe; b. at least one elongated heat-tube coextensive in length with at least a section of said pipe, said tube being of a metal having magnetic properties and conducting electricity, said heat-tube being secured in heat exchange relation with and having a substantial part of its wall in common with the wall of said transport-pipe; c. a source of AC having a first terminal and a second terminal; d. an electrical connection between the first terminal of the source of the AC and the one end of said heat-tube; e. an electrical conductor extending for a substantial distance through the inside of said heat-tube from said one end to the other and insulated electrically therefrom; f. an electrical connection between the second terminal of the source of the AC and the end of the said electrical conductor which is near the electrical connection of said heat-tube and said first terminal of the source of AC g. an electrical connection between the said heat-tube and the said electrical conductor remote from its electrical connection with the said source of AC; h. an AC circuit thus established from the said second terminal of the said AC source through the substantial distance of the said electrical conductor inside the heat-tube, then back through the said heat-tube, so as to produce a skin effect current on the inner surface of the said heat-tube, thus producing heat; and said AC circuit being completed back to the first terminal of the source of the AC; whereby i. a substantial part of the said heat produced is transferred to said fluid through said wall which is common to both said heat-tube and said transport-pipe.
Claim 2
Dependent Claim
293 words
In the system for heating a fluid being transported in a pipe comprising: a. a fluid transport-pipe; b. at least one elongated heat-tube coextensive in length with at least a section of said pipe, said tube being of a metal having magnetic properties and conducting electricity, said heat-tube being secured in heat exchange relation with and having a substantial part of its wall in common with the wall of said transport-pipe; c. a source of AC having a first terminal and a second terminal; d. an electrical connection between the first terminal of the source of the AC and the one end of said heat-tube; e. an electrical conductor extending for a substantial distance through the inside of said heat-tube from said one end to the other and insulated electrically therefrom; f. an electrical connection between the second terminal of the source of the AC and the end of the said electrical conductor which is near the electrical connection of said heat-tube and said first terminal of the source of AC g. an electrical connection between the said heat-tube and the said electrical conductor remote from its electrical connection with the said source of AC; h. an AC circuit thus established from the said second terminal of the said AC source through the substantial distance of the said electrical conductor inside the heat-tube, then back through the said heat-tube, so as to produce a skin effect current on the inner surface of the said heat-tube, thus producing heat; and said AC circuit being completed back to the first terminal of the source of the AC; whereby i. a substantial part of the said heat produced is transferred to said fluid through said wall which is common to both said heat-tube and said transport-pipe.
Claim 3
Dependent Claim
19 words
In the system of claim 1 wherein the said fluid transport-pipe and the said heat-tube are constructed of steel.
Claim 4
Dependent Claim
137 words
In the system of claim 1 wherein: a. the transport-pipe is of cylindrical and the internal surface of said heat-tube comprises a portion of the external cylindrical surface of said transport-pipe between two longitudinal straight line elements generating said cylindrical surface and the inner surface of a strip of steel which covers said external surface of the transport-pipe between said straight line generating elements thereof; b. said strip of steel is formed as a concave trough of radius of curvature substantially less than that of the normal outside surface of the said transport pipe; and c. the longitudinal edges of said concave trough are firmly contacted against said two straight line generating elements of the said transport-pipe to make an electrical connection between said concave trough and said transport-pipe and to encompass the said external surface between.
Claim 5
Dependent Claim
46 words
In the system of claim 3, wherein the longitudinal edges of the said concave trough are welded to the said transport-pipe along the said longitudinal straight line elements generating said cylindrical surface of the said transport-pipe which said edges are in contact with the said transport-pipe.
Claim 6
Dependent Claim
41 words
In the system of claim 3 wherein at least a part of the outer surface of the said transPort-pipe between the said two longitudinal straight line elements generating said cylindrical surface and defining the internal surface of the heat-tube is flattened.
Claim 7
Dependent Claim
135 words
In the system of claim 1, wherein: a. the transport-pipe is cylindrical and the internal surface of the said heat-tube comprises a part of the external cylindrical surface of a transport-pipe between two straight line elements generating the cylindrical surface and the inner surface of a strip of steel which covers said part of the external surface of the transport-pipe; b. at least a part of the external surface of said transport-pipe comprising said internal surface of the heat-tube is formed to provide a generally longitudinal inwardly directed groove of size to accommodate at least in part the said electric conductor extending inside said heat-tube; and c. the longitudinal edges of said strip of steel are firmly contacted against said two straight line elements of the said transport-pipe, to encompass the said external surface between.
Claim 8
Dependent Claim
43 words
In the system of claim 1 wherein the said heat-tube is integrally formed with said transport-pipe as one of two channels formed in the manufacture of a transport-pipe, the second of said two channels being used for transport of said fluid being heated.
Claim 9
Dependent Claim
49 words
In the system of claim 1, wherein the said heat-tube is welded between the two edges of at least one piece of formed skelp to become an integral part of the wall of said transport-pipe, which results from the joining of the edges of the skelp to the heat-tube.
Claim 10
Dependent Claim
34 words
In the system of claim 8, wherein at least two such heat-tubes are welded between edges of skelp in the same length of said transport-pipe, there being a piece of skelp between adjacent heat-tubes.
Claim 11
Dependent Claim
47 words
In the system of claim 8, wherein said heat-tube is welded between the two edges of said skelp so that it extends into said transport-pipe with at least a part of the exterior surface of said heat-tube being in contact with the fluid flowing in said transport-pipe.
Claim 12
Dependent Claim
30 words
In the system of claim 10, wherein said heat-tube is made in the form of a helix winding around and included as a part of said wall of said transport-pipe.
Claim 13
Dependent Claim
42 words
In the system of claim 8, wherein a part of the said heat-tube extends outside of the surface of the said transport-pipe after the said welding and is pressed inwardly to make its surface conform more nearly to that of the transport-pipe.
Claim 14
Dependent Claim
31 words
In the system of claim 8, wherein the said heat-tube is made in the form of a helix winding around and included as a part of said wall of said transport-pipe.
Claim 15
Dependent Claim
21 words
In the system of claim 1, wherein the said heat-tube is in the form of a helix winding around said transport-pipe.
Claim 16
Dependent Claim
131 words
In the system of claim 1, wherein: a. the internal surface of said heat-tube comprises a portion of the external cylindrical surface of said transport-pipe between two uniformly spaced helices generated on the external surface thereof and the inner surface of a strip of metal having magnetic properties and conducting electricity which overlies said electrical conductor and covers said external surface of said transport-pipe between the two uniformly spaced helices thereon; b. said strip is formed as a concave trough of radius of curvature substantially less than that of the outside surface of the said transport-pipe; and c. the longitudinal edges of said concave trough are firmly contacted against said two uniformly spaced helices to make an electrical connection with said transport-pipe and to encompass its external surface between said helices.
Claim 17
Dependent Claim
37 words
In the system of claim 15, wherein said transport-pipe and said strip are of steel and are firmly contacted by welding the edges of said strip to the said external surface of said transport-pipe along said helices.
Claim 18
Dependent Claim
100 words
In the system of claim 1, wherein the said heat-tube, including the point of entrance of said electrical connection to said electrical conductor extending for a substantial distance inside said heat-tube, is made vacuumtight, and said heat-tube is connected to a vacuum system comprising a pressure gauge, a vacuum pump, and a valve allowing the vacuum pump to be shut off from the heat-tube, said pressure gauge indicating subatmospheric pressure within the said heat-tube after evacuation by said vacuum pump; and increase in said atmospheric pressure after said evacuation and after closing said valve indicating a leak in said heat-tube.
Claim 19
Dependent Claim
40 words
In the system of claim 1, wherein the space inside the heat-tube and surrounding the said electrical conductor extending for a substantial distance therein is filled with a material nonconductive to electricity comprising an oxide of an alkaline earth metal.
Claim 20
Dependent Claim
75 words
In the system of claim 1 wherein: a. the said transport-pipe provided with at least one pair of heat-tubes distributed along its length, heating respective sections thereof and longitudinally numbered alternately odd and even; b. the said odd-numbered and even-numbered heat-tubes of a pair running in opposite directions from ends which are adjacent; said transport-pipe over a length equal to the sum of the lengths of each pair of heat-tubes, one odd-numbered, and one even-numbered.
Claim 21
Dependent Claim
82 words
In the system of claim 1, wherein the said heat-tube, including the point of entrance of said electrical connection to said electrical conductor extending for a substantial distance inside said heat-tube, is made tight against fluid pressure; and said heat-tube is connected to a supply of oil under pressure which is indicated by a pressure gauge so that when said pressure gauge shows a decrease in said pressure of said oil within the said heat-tube, a leak in said heat-tube is indicated.
Claim 22
Dependent Claim
24 words
In the system of claim 1, wherein each heat-tube comprises a plurality of sections arranged end-to-end and each section having a different internal perimeter.
Claim 23
Independent Claim
268 words
A system for heating materials being transported comprising: a. an elongated pipe with walls of a heat-conductive material in which said materials are being transported; b. an elongated heat-tube of ferromagnetic material formed in part by a generally elongated portion of the surface of the wall of said elongated pipe and in part by an elongated shaped strip of ferromagnetic material which overlies said generally elongated portion of said elongated pipe; c. means for attaching the edges of said elongated shaped strip forming part of the wall of the heat-tube throughout its length tightly against the generally elongated portion of said surface of said elongated pipe so as to form a contact angle at least 90* with said surface; d. an electrical connection between a source of AC and a first end of said heat-tube; e. an electrical conductor extending through the inside of said heat-tube from said first end to the other end thereof and insulated electrically from said heat-tube; f. an electrical connection between the source of the AC and said end of the said electrical conductor which is near the said first end of said heat-tube; g. an electrical connection between the said electrical conductor and the other end of said heat-tube; h. whereby an AC circuit is thus established from the said AC source through the said electrical conductor inside the heat-tube, then back through said heat-tube to the source of the AC; thus i. producing a skin effect current on the inner surface of the said heat-tube so as to develop heat which passes to said elongated pipe and said materials being transported.
Claim 24
Independent Claim
268 words
A system for heating materials being transported comprising: a. an elongated pipe with walls of a heat-conductive material in which said materials are being transported; b. an elongated heat-tube of ferromagnetic material formed in part by a generally elongated portion of the surface of the wall of said elongated pipe and in part by an elongated shaped strip of ferromagnetic material which overlies said generally elongated portion of said elongated pipe; c. means for attaching the edges of said elongated shaped strip forming part of the wall of the heat-tube throughout its length tightly against the generally elongated portion of said surface of said elongated pipe so as to form a contact angle at least 90* with said surface; d. an electrical connection between a source of AC and a first end of said heat-tube; e. an electrical conductor extending through the inside of said heat-tube from said first end to the other end thereof and insulated electrically from said heat-tube; f. an electrical connection between the source of the AC and said end of the said electrical conductor which is near the said first end of said heat-tube; g. an electrical connection between the said electrical conductor and the other end of said heat-tube; h. whereby an AC circuit is thus established from the said AC source through the said electrical conductor inside the heat-tube, then back through said heat-tube to the source of the AC; thus i. producing a skin effect current on the inner surface of the said heat-tube so as to develop heat which passes to said elongated pipe and said materials being transported.
Claim 25
Dependent Claim
35 words
A heating system as in claim 22, wherein the part of the outer wall of said elongated pipe forming part of the heat-tube is flattened in at least a part of said generally elongated portion.
Claim 26
Dependent Claim
31 words
A heating system as in claim 22, wherein said elongated pipe is of generally cylindrical shape and the part thereof used in forming said heat-tube is the convex outer surface thereof.
Claim 27
Dependent Claim
29 words
A heating system as in claim 22, wherein said elongated shaped strip completing said heAt-tube overlies the outside of said elongated pipe and has a generally concave inner surface.
Claim 28
Dependent Claim
65 words
A heating system as in claim 22, wherein said part of said elongated pipe forming said heat-tube is indented inwardly throughout the length of the inner wall of said elongated pipe to form an open channel, said elongated shaped strip which completes the heat-tube being fastened to the outer wall of said elongated pipe so as to cover the open channel formed by the indent.
Claim 29
Dependent Claim
54 words
A heating system as in claim 22, wherein said elongated shaped strip completing the heat-tube overlies and is connected integrally and throughout its length across a portion of the inner wall of said elongated pipe so as to form two channels, a major one for the transport-pipe and a minor one for the heat-tube.
Claim 30
Dependent Claim
33 words
A heating system as in claim 22, wherein said elongated shaped strip completing the heat-tube is connected integrally and throughout its length across a portion of the inner wall of said elongated pipe.
Claim 31
Dependent Claim
27 words
A heating system as in claim 28, wherein said elongated shaped strip has a generally convex surface on the side in contact with said materials being transported.
Claim 32
Dependent Claim
25 words
A system as in claim 22, wherein said heat-tube follows a three dimensional curved path in being formed along the wall of said elongated pipe.
Claim 33
Dependent Claim
14 words
A heating system as in claim 30, wherein said curved path is a helix.
Claim 34
Dependent Claim
23 words
A heating system as in claim 22, wherein said heat-tube follows a helix in being formed along the wall of said elongated pipe.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |