US3522440A - Method for supplying electricity to a heat-generating pipe utilizing skin effect of a.c. - Google Patents

Method for supplying electricity to a heat-generating pipe utilizing skin effect of a.c. Download PDF

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Publication number
US3522440A
US3522440A US3522440DA US3522440A US 3522440 A US3522440 A US 3522440A US 3522440D A US3522440D A US 3522440DA US 3522440 A US3522440 A US 3522440A
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Prior art keywords
heat
pipe
generating pipe
supplying electricity
generating
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Expired - Lifetime
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English (en)
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Masao Ando
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JNC Corp
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Chisso Corp
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/0014—Devices wherein the heating current flows through particular resistances
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
    • F24H1/101—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply
    • F24H1/102—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply with resistance
    • F24H1/105—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply with resistance formed by the tube through which the fluid flows

Definitions

  • This invention relates to a method for supplying electricity to a heat-generating pipe which utilizes the skin effect of A.C. More particularly, it relates to a method for supplying electricity to a heat-generating pipe of ferromagnetic material which utilizes the skin effect of A.C. and to an A.C. load, such as a liquid transporting pump, by the use of the same insulated conductor lines in such a way that alternating currents are supplied to a heatgenerating pipe through the insulated conductor lines accommodated in said heat-generating pipe and simultaneously to an A.C.
  • FIG. 1 of the drawing is a pipe of ferromagnetic material and 5 is a conductor, e.g. an insulated electric wire, installed between both the end of the pipe in electrically insulated relation from the pipe 2, one end of which is connected to an A.C. supply source 20 and the other end of which is connected to a terminal 14 of the pipe.
  • A.C. supply source 20- an electric potential of alternating current is supplied from the A.C. supply source 20- to the circuit consisting of the conductor 5 and the pipe 2
  • the current flowing between the terminals 14 and 15 of the pipe 2 appears only at the skin part of the inner wall portion of the pipe 2 because .of skin effect.
  • the region through which the current flows is called a penetration depth. If the penetration depth is designated s (cm.), the inner diameter of the pipe is designated d (cm.) and if d s, s can be expressed approximately by a formula:
  • p is the specific resistance of the pipe material used (52 cm.)
  • a is the magnetic permeability
  • f is frequency (cycles/sec).
  • the current concentrates in the skin part of the inner wall portion of the pipe 2 and current does not appear in the outer surface zone of the heat-generating pipe in the circuit.
  • Joules heat is generated in the skin part of the inner wall portion of the pipe 2 by the concentrated current and transmitted to the outside of the pipe through the pipe wall and can be utilized in heating various objects.
  • FIG. 2 shows a crosssectional view of such a heat-generating pipe installed together with a liquid transporting pipe line to be heated therewith.
  • 22 is a liquid transporting pipe and there are fixed three heat-generating pipes 1, 2 and 3 over the entire length of the pipe line in substantially axially parallel relation therewith.
  • FIG. 1 is a schematic circuit diagram of one embodiment of the present invention and FIG. 2 is a cross-sectional view of a heat-generating pipe which utilizes skin effect of A.C. and is installed in contact with a longdistance liquid transportation pipe.
  • the insulated conductor line supported within the heat-generating pipe in electrically insulated relation can be used for heating of the liquid before starting of liquid transportation and as a feeder line for the power of liquid transporting pumps.
  • the heat-generating pipe 1 in FIG. 1 shows one example of such a method for supplying electricity.
  • pipes 1, 2 and 3 are entirely the same heatgenerating pipes, the insulated conductor lines accommodated in said pipes are not the same since pipe 1 includes conductors 4, 4 and 4" for a load which requires three phase A.C.
  • the element 11 is a motor for a liquid sending pump, and the liquid is sent from here toward the side of the pipe on which the A.C. supply source is located.
  • the heatgenerating pipes 1, 2 and 3 are all used for the purpose of heating.
  • A.C. flows through separate lines 4, 4 and 4", and is delivered to the end of the heatgenerating pipe and flows through the skin part of its inner wall portion.
  • the heating is stopped, and transportation of liquid is started by supplying electricity only to the pipe 1. Namely, when the switches 18 and 7 are opened and the switch 8 is closed, a three phase A.C. flows through the lines 4, 4 and 4 and motor 11 is energized. If the three currents are balanced and there is no zero phase current, in this case, there will be no eddy current nor heat generation in the pipe as in case of common pipe used as a sheath of the conductor line.
  • the pipes 2 and 3 are not supplied with power when liquid is being transported, but if necessary it is possible to supply electricity in order to use them for heating.
  • FIG. 1 illustrates a case where the load requires three phase A.C.
  • a transformer 21 is used for the change of voltage, when the voltage of the load is not the same as that of the circuit of the heatgenerating pipe, i.e. that of the initial supply source, but it is possible to install a tertiary winding for the use of a relay in order to make the switch automatically controllable. If it is controlled automatically, the shaft between heating and liquid transmission can be carried out safely even when the motor 11 is installed at a location remote from the A.C. supply source because remote control from the location near the A.C. supply source is possible.
  • the present invention exhibits exceedingly superior effectiveness in pipe lines used in the transportation of such oils. Particularly, the lack of need of an additional feeder which connects an A.C. supply source to a load gives better economical advantage with the increase of the length of pipe line.
  • the method of the present invention looks to be applicable to other heat-generating methods but in reality, only a method involving a heat-generating pipe utilizing the skin effect of AC. can give the effectiveness desired.
  • other heat-generating method e.g. a case of M1. (mineral insulated) cable which uses a cable insulated with an inorganic substance, is utilized all the heat generated comes from the electric cable and the total potential drop occurs in the electric cable. If a load requires the same quantity of electric current as in case of heating, the potential at the load 11 in FIG. 1 should be zero and not receive electric power from the supply source 20.
  • the conductor line in order to obtain at the load 11 an electric potential corresponding to of the potential of the supply source 20, it is only possible totransmit a current corresponding to approximately of the current for heating purpose, and as a feeder to the load, the conductor line will be of a capacity exceedingly small. Whereas in the method of the present invention, nearly 90% of the heat generated comes from the body of the heat-generating pipe and only 10% of it is produced in the conductor line. Accordingly, the potential drop in the conductor line is also only 10%. Even when a load requires the same quantity of current as in case of heating, the conductor line has a capacity sufficient to serve also as a feeder. It is desirous to pay attention to increase in heat conduction from a heatgenerating pipe to a liquid transporting pipe by contact or welding when the heat-generating pipe is used to heat the liquid in the transporting pipe.
  • heat-conductive liquid useful for the above-mentioned purpose Water, or an aqueous solution of a salt such as sea water is preferred but oils, fats, petroleum oils, alcohols, and aqueous solutions of the foregoing members are also effective.
  • the insulated conductor line is provided as an insulated cable for high voltage use, the electric field intensity around the surface of the insulated material can be made uniform and hence the durability of the insulating material can be improved by selecting a relatively electrically conductive material from among heat-conductive liquids useful in filling the clearance part of the pipe.
  • a method for supplying electricity at one time to at least one heat-generating pipe of ferromagnetic material and at another time to an A.C. load which comprises at said one time connecting a plurality of conductor lines, connected to an A.C. supply source and inserted within said heat-generating pipe in its longitudinal direction in electrically insulated relation from the inner wall of said heat-generating pipe, electrically to the end of said heat-generating pipe remote from the AS. supply source and simultaneously connecting the other end of said heat-generating pipe to said A.C.
  • a method according to claim 1 wherein the A.C. load is a motor for sending liquid to be heated, and electric lights.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Fluid Mechanics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • General Induction Heating (AREA)
US3522440D 1967-03-22 1968-03-28 Method for supplying electricity to a heat-generating pipe utilizing skin effect of a.c. Expired - Lifetime US3522440A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP1784567 1967-03-22
US71672668A 1968-03-28 1968-03-28

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US3522440A true US3522440A (en) 1970-08-04

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US3522440D Expired - Lifetime US3522440A (en) 1967-03-22 1968-03-28 Method for supplying electricity to a heat-generating pipe utilizing skin effect of a.c.

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US (1) US3522440A (enrdf_load_stackoverflow)
FR (1) FR1568234A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3706872A (en) * 1970-05-15 1972-12-19 William J Trabilcy System for electrically heating fluid-conveying pipe lines and other structures
US3974398A (en) * 1971-01-18 1976-08-10 Othmer Donald F Wire and steel tube as AC cable
US4408117A (en) * 1980-05-28 1983-10-04 Yurkanin Robert M Impedance heating system with skin effect particularly for railroad tank cars
EP0130671A3 (en) * 1983-05-26 1986-12-17 Metcal Inc. Multiple temperature autoregulating heater
US4645906A (en) * 1985-03-04 1987-02-24 Thermon Manufacturing Company Reduced resistance skin effect heat generating system
US20020109068A1 (en) * 1999-06-24 2002-08-15 Staskiewicz Alma L. Valve for use in producing cast concrete articles

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3575581A (en) * 1969-05-15 1971-04-20 Chisso Corp Heat-generating pipe utilizing skin effect current controlled locally in heat generation by short-circuiting bridges

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3410977A (en) * 1966-03-28 1968-11-12 Ando Masao Method of and apparatus for heating the surface part of various construction materials

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3410977A (en) * 1966-03-28 1968-11-12 Ando Masao Method of and apparatus for heating the surface part of various construction materials

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3706872A (en) * 1970-05-15 1972-12-19 William J Trabilcy System for electrically heating fluid-conveying pipe lines and other structures
US3974398A (en) * 1971-01-18 1976-08-10 Othmer Donald F Wire and steel tube as AC cable
US4408117A (en) * 1980-05-28 1983-10-04 Yurkanin Robert M Impedance heating system with skin effect particularly for railroad tank cars
EP0130671A3 (en) * 1983-05-26 1986-12-17 Metcal Inc. Multiple temperature autoregulating heater
US4645906A (en) * 1985-03-04 1987-02-24 Thermon Manufacturing Company Reduced resistance skin effect heat generating system
US20020109068A1 (en) * 1999-06-24 2002-08-15 Staskiewicz Alma L. Valve for use in producing cast concrete articles

Also Published As

Publication number Publication date
FR1568234A (enrdf_load_stackoverflow) 1969-05-23

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