US3617699A - A system for electrically heating a fluid being transported in a pipe - Google Patents

A system for electrically heating a fluid being transported in a pipe Download PDF

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US3617699A
US3617699A US3617699DA US3617699A US 3617699 A US3617699 A US 3617699A US 3617699D A US3617699D A US 3617699DA US 3617699 A US3617699 A US 3617699A
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heat
tube
pipe
transport
elongated
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Donald F Othmer
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    • 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
    • F24H1/12—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 in which the water is kept separate from the heating medium
    • F24H1/121—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 in which the water is kept separate from the heating medium using electric energy supply
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L53/00—Heating of pipes or pipe systems; Cooling of pipes or pipe systems
    • F16L53/30—Heating of pipes or pipe systems
    • F16L53/34—Heating of pipes or pipe systems using electric, magnetic or electromagnetic fields, e.g. using induction, dielectric or microwave heating
    • 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
    • F24H9/00—Details
    • F24H9/40—Arrangements for preventing corrosion
    • F24H9/45—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means
    • 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
    • F24H9/00—Details
    • F24H9/40—Arrangements for preventing corrosion
    • F24H9/45—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means
    • F24H9/455—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means for water heaters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/6416—With heating or cooling of the system
    • Y10T137/6606—With electric heating element

Definitions

  • 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 thereofis 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.
  • the heat-tube can be formed by welding a concave strip to the outer cylinder surface of the pipe with the conductor disposed therebetween.
  • 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 heattube is either evacuated or pressurized and means to detect pressure changes indicative of heat-tube leakage is provided.
  • This invention relates to the use of the skin-effect of alternating current AC flowing with an adjacent or concentric steel conductor supplying the return or"back" leg of the circuit, thus causing induction and magnetic effects which greatly increase the effective resistance of the steel conductor.
  • a hot fluid usually steam
  • tracer tube or trace
  • This heat-tube has always been substantially axially parallel to the oil-pipe, with an internal insulated copper wire.
  • This internal electric wire forms one leg out of the AC circuit; and its other terminal was at the far end of the heattube on the inside thereof. Electric current flows back on the return leg of the circuit on the inside wall of the heat-tube because of the skineffect, with no current flowing on the outside wall, if the steel tube is more than about 0.04-inches thick.
  • the other junction to the source of AC is a point at the near end of the inner surface of the heat-tube adjacent the entrance of the insulated copper wire into theheattube to carry the AC to its far end.
  • Theheat-tube has always been attached in substantially axially parallel relation with the oil-pipe and along one of its elements by welding to this much larger pipe which carries the fluid. Temperatures of theheat-tube more than a few degrees Fahrenheit higher than that of the oil-pipe could not be tolerated because expansion strains set up cracked off this type of attachment
  • the heat-tube again in substantially axially parallel relation has been installed inside of the. oil-pipe supported along the axis by sets of three braces at suitable distances,
  • the electro magnetic flux surrounding a wire carrying an AC has been found to extend without practical diminution of its influence on the skin-effect for some distance, if not shielded by another metal. Thus, it has been found possible to use a larger individual heat-tube than before.
  • the use of the larger individual heat-tubes allows a much greater elTective conductor-resistor, i.e., the inner skin of the larger heat-tube. Particularly it allows a heavier internal insulated electric wire, which larger size wire is necessary for carrying the high voltage and intensity AC required for heating long distance pipelines. Also, the larger heat-tube allows the use of a poorer conductor for the AC, hence of larger diameter for the same intensity of AC than the usual copper wire.
  • R constant x p
  • the effective resistance of a conductor having skin-effect is inversely proportional to the effective cross sectional area of the skin conductor. This cross sectional area for a heat-tube is directly proportional to the effective skin depth; thus R is proportional to or, in heat-tubes:
  • Variations in this skin-effect are influenced by changes in the resistivity and the magnetic permeability which are caused by the temperature of the conductor.
  • the gradation of current density against wall thickness from the inner surface of a small heat-tube is so large that, with the voltage drop experienced with steel tubes in heat-tube service (i.e., usually between 0.05 and 1.0 volts per lineal foot) and at temperatures up to about 400 to 500 F., the effective zero of current flow or availability is reached within a depth somewhat less than approximately onesixteenth inch from the inside tube surface. For most mild steels worked with, this depth has been found to be between 0.025 inch and 0.075 inch. For any particular steel, the effective conductor area is thus the inner perimeter of the heattube times a value of the depth, 5, between 0.025 inch and 0.075 inch.
  • the thickness of the tube from the innner to the outer wall should be about twice the skin thickness, or one-eighth inch under the usual intensities of AC flow used. There will then be no measurable voltage or power loss, even when the outside of the heat-tube is grounded or submerged in salt water. Unburied pipelines are grounded at reasonable distances, and pipelines in corrosive conditions may have the conventional sacrificial cathodic protection system with no interference with the skin-effect heating.
  • a metal which has properties which give effectively only a thin skin for AC conductance gives the least effective conducting cross-sectional area, and hence the greatest resistance.
  • Metals of desired characteristics may be selected from the above-indicated relation of skin thickness as dependo have a relatively pronounced skin-effect, i.e., a thin skin ofconductance for AC under conditions of the present invention are: very pure iron; iron-nickel alloys, as ,l-lipernikythose with a small amount of manganese, called Permalloys; and
  • steel is used herein to described ,the material .of construction of thewheat-tube, it may. be -..understood that this term formildor-ordinary carbon steel is used only as an example; and other metals, bothferrousand nonferrous, may also be used. Usually they have a less-desira ble skin-effect, or are more expensive. In some particular instances other physical or chemical properties ofother metallic conductors makethemworthy of consideration; but carbon steel is preferred for its cheapne ss, workability, and availability in many forms. Thus, the word steeli isused as, anexample without being a limitation of the material-of construction-of the heat-tubes of this invention.
  • com- .mercial fluids transported by pipe include molasses, other food syrups or melts-such as butter, other oils and fats, chocolate, etc-strongsulfuric.acid, tar, bitumen and many others.
  • Some materials are frozen solid at some, ambient temperatures; in particular, there may-be noted water and aqueous solutions, sulfur, also benzene, acetic acid, etc. These-mustbe kept heated to prevent congealing or freezing if the ambient temperature is below the respective solidification temperature and sufficient heat above the freezing point cannot beadded before the fluid entersthe cold. length of pipe.
  • the pipe With acetic acid, the pipe may be of aluminum, ;stainless, steel, or copper-because of corrosion of carbon steel.
  • the heat-tube would be of steel and particularcare would be taken that'its thickness be at least twice that of the skinor penetration depth of the AC. Most desirable would be a stainless steel; in other cases, it may be that ice and snow, with or without liquid water being present, fall within the classification of fluids to .be heated or melted, because of their being adjacent to the heattube.
  • Tem- ,peratures as high or-higher than400" to 500 F. may be reached in an "oil-pipe.
  • the heat-tube may be of a shape. other than cylindrical and have varied configurations in respect to the oil-pipe or other structuretobe heated; or it may be an integral part thereof. However, it is referred to here simply as the heat-tube" regardlessof its cross-sectional shape-.or convolutions, whether it ism'ade of several sections formed together longitudinally,
  • the electricconductor' for the one side of the AC circuit ifcarried inside of'the heat-tube in whatever configuration-that may take, may be a copperwire in most cases-orjof other commercial metals or alloys. it may be of single or multi- -ple strands-of any desired arrangement-or cross'section. It is referred to usually simply as the electric-wire.”
  • Theelectric wire may bemade of other than usual metals.
  • Electrodesodium may be-used as the conductor.
  • a lining tube and hence is utilized in heating the adjacent materials, ,e.g.,' if attached to anoil-pipeto the oil therein.
  • the electric wire is of copper, steel, or other metal of. greater resistivity
  • the additional heat which it givesup due to thelarger-line loss willall be utilized in the fundamental heatingpperation.
  • a relatively inexpensive steel conductor or wire may be used in place of the more expensive but standard copperrllowever, theheatso generated within the wire willhave to pass through the electrical insulation,thence materials.
  • THe electric wire will usually have, a somewhat higher temperaturev than that of'theheat tube;. and thisnmust be considered in specifying insulation .lnsulation for the electric wire-may. be of anyv suitable material whichwill maintain its physical, electrical, and chemicalgcharacteristics as the temperature of the heat-tube.
  • Polyvinyl chloride is satisfactoryup to about 180 F., polyethylene up to about. 215 F., and specially cross-linked polyethylene I up,to about 260203".
  • Silicon resin materials are available to be used from 350-400 F. Higher temperatures up to 500 F. or
  • the electric wire may operate at higher temperatures; and ceramic and other special inorganic insulations may be used in powder, cement, or bead form for these higher temperatures.
  • Special inorganic powders have been found to be useful for this purpose, particularly the oxides of the alkaline earth metals such as Beryllium, Magnesium, and Calcium. These oxides, such as magnesia, may be incorporated as an insulator inside the heat-tube and around the electric wire if of copper or particularly if of iron or other material of greater resistivity than copper. This powder must be firmly packed with the wire correctly aligned in the center of the tube in a factory operation. To compact adequately the insulation powder so that its heat conductivity will be improved, the assembled heat-tube, insulation, and wire may be passed hot or cold through rolls to reduce the size of the heat-tube slightly.
  • the alkaline earth metals such as Beryllium, Magnesium, and Calcium.
  • a notable one of these oxides in powder form is beryllium oxide, which has excellent electrical insulation properties, while being a good heat conductor. it, like magnesium oxide, or calcium oxide, may be used in the upper limit of effectiveness of heat-tubes of the high heat fluxes of the present invention, but is too expensive for most uses.
  • the heat tube preformed with the electric wire and its heatproof insulation may then be brazed or welded into the oil-pipe in the shop or in the field by one of the several designs of this invention.
  • Thermal losses are minimized by application of conventional insulation materials in the usual manner to pipelines heated by this or other methods.
  • Such insulation is not shown in the Figures as it is not a part of this invention, by itself.
  • one of the major objects of this invention as applied to the heating of pipelines is the improvement of the ease and economy of application of insulation, because the rough contours of a small heat-tube (or several or more such) on the periphery of the large oil-pipe have been largely eliminated. insulation is a very substantial part of the cost of a large pipeline.
  • the angle of contact of the oil-pipe with the heattube is 0, i.e., they are tangent to each other. Because of the poor contact, only low-heat fluxes per unit length or per foot of internal perimeter of the oil may be used without excessive temperatures of the heat-tube. These high temperatures mean higher thermal losses, particularly since effective insulation is difficult.
  • the oil-pipe to be heated may be of any desired size; and those to be considered in practice range from 1 to 48 inches in diameter.
  • the size of the heat-tube made of the steel used for conventional pipelines depends on several conditions, principally: heat input required to attain or maintain the desired temperature of the contents of the oil-pipe of given size and flow, the AC voltage available, and the length.
  • the wall should be at least %-inch thick for electrical, mechanical, and corrosion considerations.
  • the size of the heat-tube to be used in all practical cases where the diameters are greater than about 4 times A, the depth of the effective conducting skin has been found thus to depend on its internal perimeter, not on its internal cross section, as it would be if carrying a fluid-and not on its wall cross section as it would be if carrying a DC current as a conventional electric conductor.
  • the essential criterion of the inside perimeter or inside surface per unit length is not always attained most advantageously by the circular tube which is usually most readily available and at the lowest cost.
  • the surface of the oil-pipe may, in some cases, be used as part of the inner surface of the heat-tube, and this saves total weight of metal used. Furthermore, if the heat-tube is thus made an integral part of the wall of the oil-pipe, a part of the effective wall of the heat-tube is in contact with the oil being transported. Such considerations as good thermal contact and ease of insulation have been found to be important factors of optimum design, to allow good heat transfer.
  • the ratio of the inside perimeter of the heat-tube (or sums of perimeters if more than one heat-tube) to the outside perimeter of the oil-pipe indicates roughly the ratio of the surface of electrical resistance heat input to the surface of heat output to the surroundings; i.e., heat losses of the system under conditions of constant temperature of the oil.
  • the ratios as indicated by FIGS. 1 to 4 are not the optimum for any particular design conditions, since the figures are drawn without scale. in the past art, this ratio of the inside perimeter of the heat-tube (or the sum of the inside perimeters of all of the heat-tubes, if more than one is used,) to the outside perimeter of the oil-pipe has been in the range of about one-half to onefifth for moderate heat duties.
  • this ratio may be reduced to 1/7 to 1/10 or even 1/20 under comparable moderate heating conditions. This is of considerable importance under such circumstances as require to 200 watts or more of heat per foot of oil-pipe length, e.g., a 48- inch line under -50 F. ambient temperature.
  • the electrical heat input supplied from the AC ofthe prior art was about 10 to 15 watts per lineal foot of the heat-tube.
  • Higher heat inputs to the tube now increase greatly the temperature difference between the electric wire and the wall of the oil-pipe above the 3 to 4 F. regarded as a desirable maximum-usual operation desired was in the 2 to 3 F. range of temperature difference between the two walls.
  • Higher temperatures of the heat-tubes now possible because of improved designs, including their integration into the oilpipe and the higher heat flux allow temperature differences between electric wire and oil-pipe wall of over 100 F. and the operation of large pipelines under severe winter conditions.
  • heat-tubes to be described have been found to improve greatly the heat flow from tube to pipe, and to minimize the temperature difference between them. They are useful under low heat flux conditions for their many advantages, but particularly, they make possible much higher heat fluxes. Thus, in oil-pipes up to 30 inches in diameter, only one such heat-tube parallel to the axis is necessary usually instead of thetwo to six of the prior art, not more than two are needed in sizes up to 48 inches, usually not more than three in sizes over 48 inches.
  • FIG. 1 shows a made-in-place heat-tube 2, having the cross section of a lune. It is constructed by welding, 5, along its two edges a strip of one-eighth inch or thicker steel against two elements of the cylindrical oilpile, l.
  • the steel strip is preformed as a trough with a radius of curvature substantially less than that of the outer surface of the heat-tube.
  • the outer surface of the oil-pipe itself, between the two elements, becomes an effective part of the heat-tube and carries part of the AC by the skin-effect conduction on this part of its outer surface. Its skin resistance to the AC gives heat directly to the oil-pipe.
  • the weight added to the pipeline by the heat-tube is less for the same internal perimeter. As much as 40 to 45 percent of the heat-tube is thus made up of the oil-pipe surface, which surface performs a dual service.
  • the built-up heattube section again approaches an angle of 180, with the surface of the oil-pipe.
  • the electric wire, 3, is indicated inside the heat-tube, 2, of FIG. I. as of special flattened cross section. Alternately, one, two, or more conventional insulated wires may be used to conduct the necessary AC. 1
  • FIG. 2(a) is shown a modification of the system of FIG. 1, which has a better shape for accommodating a large circular electric wire, 3, with normal insulation, 4.
  • the closer conformance of the shaped strip, 2, to the periphery of the oilpipe, 1, allows better heat transfer and some advantage in welding.
  • FIG. 2(b) Another design of heat-tube is shown in FIG. 2(b), as if applied to the same oil-pipe, l.
  • a special groove, 31, is formed by rolling or otherwise in the wall of l, and this is covered by a strip 2, of steel at least one-eighth inch thick, welded in place along both edges.
  • This provides a heat-tube having an even larger part of its inner periphery made by the outer surface of the oil-pipe and with excellent heat transfer relation to the fluid inside, and an outer surface of the combination hardly disturbed from the circular. Thus, it is readily insulated.
  • the groove, 31, is shown deep enough to include entirely the electric wire, 3, a shallower groove and a concave formed cover strip may also be used.
  • FIG. 2(c) Still another variation of the oil-pipe, somewhat easier to roll, is shown in FIG. 2(c) with a narrow flattened longitudinal section, 21, of the oil-pipe wall specially rolled during the production of the tube, and a formed strip 2 welded over it throughout the length, with the welded metal forming beams 5 on either side of 2.
  • the usual conductor 3 has suitable insulation 4.
  • the applied section approaches an angle of 180, with the outer surface of the oilpipe.
  • FIG. 3 shows the cross section of an oilpipe, l, with a heattube, 2, built into it in the seamless drawing and forming of the pipe.
  • Such dual duct pipes are available in small pipe sizes, usually in aluminum, which may not be used for this purpose.
  • the common wall, 41, of the heat-tube and the oil-pipe allows excellent heat transfer and the unbroken cylindrical outer surface simplifies insulation.
  • the critical angle is 180", since the common wall intersects the surface element to which may be drawn a tangent.
  • FIG. 3 Another variation of the manufacture of the type of dualchannel tube of FIG. 3 is made with rolled pipe, wherein a larger pipe, at or above the welding temperature, and a small tube, at a somewhat lower temperature, are run through forming rolls which ultimately discharges a section not unlike that of FIG. 3, except that the common wall 41 is somewhat thicker than the outer wall of the oil-pipe.
  • a much smaller tube, 2, in relation to the oil-pipe, 1, might be used than that shown in FIG. 3.
  • This two-channel pipe is probably the optimum design for those smaller sizes of oil-pipe which may be so made, but suffcient lengths of pipe of a fixed size would have to be ordered to justify a pipe mill to set up for the special rolling or other forming operations.
  • mild steel will be the desirable material of construction of this type of heat tube, as one channel with the oil-pipe as the other.
  • FIG. 4(a) A preferred design to give the advantages of the system of FIG. 3 for larger pipe sizes, 12 inches and above, and particularly larger than 24 inches, is shown in FIG. 4(a), wherein the heat-tube, 2, is integrally welded into the wall of the oil-pipe,
  • the oil-pipe, 1, is formed of skelp which is pressed and/or rolled into a pipe which is not closed and has a slit left as an opening between the adjacent edges of the skelp.
  • the heattube is inserted in this opening between the edges of the skelp.
  • the heat-tube, 2 of FIG. 4(b) has been welded in the same way as was heat-tube, 2, of FIG. 4(a) except that it is supported during welding so that its outer element is flush with the surface of the oil-pipe, with the weld-head, 5, filling the space to give a surface which may be ground as a true cylinder if desired.
  • Much of the heat-tube is thus inside the oil-pipe;
  • the outer surface of the heat-tube so constructed has an angle above 90, usually approaching or equaling [80 with the outer wall of the oil-pipe, it has excellent thermal relationship with the wall of the pipe; and it, in itself, is also in immediate contact with the fluid being transported.
  • Such heattubes pass high heat fluxes, and offer little nuisance in application of insulation.
  • each piece of skelp would then make up 120 of the finished pipe wall; and, as always, there would be the same number of seams and of heat-tubes as of pieces of skelp.
  • the integration of the heat-tube into the wall of the oil-pipe makes possible the use of very high thermal fluxes; but other advantages of this system warrant its use even with lower thermal duties.
  • a multiplicity of heat-tubes in substantially axial parallel relation has been used to attempt to minimize these disadvantages and the distance which heat will have to be transferred either through the pipe wall or through the fluid, so that a more or less uniform minimum temperature is reached.
  • the oil flowing next the inner wall may be at a distance over 8 inches away from a heat-tube; and at least some part of the oil at such distances from a source of heat will never be adequately heated and will be in viscous flow. If there is adequate heat input to heat all of the oil, some oil is therefore heated to a higher temperature than necessary, which thus wastes electric heat.
  • the helix of the heat-tube has a pitch (distance along the pipe between two turns) equal to the diameter D, its length is the hypotenuse of the right triangle, one side being D, along the element, and the other rri), the circumference.
  • this spiral winding may be applied in a double helix; and a triple helix allows the use of three phases of a standard alternator.
  • the oil-pipe of FIG. has a spirally wound heat-tube which may be applied in any one of several ways to its external surface as shown in FIGS. 1 to 4. Oil flowing near the surface crosses all of the paths of the turn pipe the helix of the heattube and thus is uniformly heated all around; its viscosity is reduced; and it flows with a minimum of friction. Since it will be uniformly heated around the tube, all of friction, interior oil, found more at start-up, will flow as a cylinder or plug" surrounded by this uniformly less viscous layer, which greases" the flow of the inner plug of cold oil. It has been found that even before ambient bulk of the oil in the center has been heated up to the temperature of that of the balance of the oil, the amount of oil pumped for a given pressure drop of the pipeline is not substantially less than after the oil is thoroughly heated throughout.
  • the flow capacity of the oil-pipe with a spiral heat-tube is always appreciably greater because of this same uniform reduction of the viscosity of the oil near the inner wall. This is with the same pressure exerted by the pump and the same heat input from the AC.
  • the excellent transfer of heat by the crossflow of oil over the area of the oil-pipe immediately adjacent the heat-tube allows an unusually large heatflux to be generated and usedeffectively by this system.
  • this spiral construction may also be used.
  • Spiral heat-tubes may be placed on a double or triple thread helix, by any of these methods, as may be necessary or advantageous to secure the desired heat effect simultaneously; and three such heat-tubes allow the balancing of the electrical circuitry with a three-phase alternator.
  • the pitch, or distance apart of the turns of the helix is equal to twice the diameter of the pipe.
  • the spiral heat-tube, 2 is formed in the yvelding between the edges of the skelp, as indicated in FIG. 3(3) for a heat-tube, 2, along an element of the oil-pipe.
  • the outer surface of the heat-tube is approxilight dashed lines. After welding, any part of the heat-tube which protrudes above the surface may be flattened to the outer wall of the oil-pipe.
  • the heat-tube may be welded into the pipe wall with its center at the midpoint, comparable to FIG. 4(a), tube 2, to reduce friction of the fluid flow; or it may be welded with its inner surface flush with the inner surface of the pipe, so that the disturbance to fluid flow is removed.
  • This last construction is not detailed in the figures, but is obvious therefrom; and it is a preferred system.
  • the helical heat-tube With the helical pitch equal to the diameter of the oil-pipe, the helical heat-tube will have about 3.3 feet of heat-tube per running foot of oil-pipe. With a double spiral, it will be twice this. Because of the greater efficiency of heat transfer, a single helix spaced on an even greater pitch than the length of the diameter may usually be used on any size oil-pipe up to at least 48 inches diameter; and on all sizes of oil-pipes, a lower power consumption for pumping may be achieved for the reasons indicated, than with heat-tubes in axial parallel relation to the oil-pipe. This is particularly true when the heat-tube is constructed with its inner surface flush with the inner surface of the oil-pipe.
  • DIMENSIONS OF SOHEDU1I;IEII 130 U.S. STANDARD STEEL The choice of the size of the heat-tube depends on the length, the size electric wire to be used, and its insulation If the length of the pipeline to be heated by a single spirally wound heat-tube is ID miles, 52,800 feet, the length of the heat tube at 30 to an element is 61,000 feet.
  • the heat-tube may be as large as 3%-inch US. Standard Pipe with dimensions as above.
  • a single or multiple stranded copper cable equivalent to 0000 copper wire may be used.
  • This 0000 copper wire has a diameter of 0.46 inches, a cross section of 21 1,600 circular mills, or 0.0662 square inches, and a resistance of 0.06 ohms per 1,000 feet at its operating temperature of about F.
  • the weight is 0.640 pounds copper per foot.
  • a built-up insulation of 0.075-inch thickness gives a copper cable of about %-inch diameter or an aluminum cable of about 1 1/ l 6-inch diameter. If the tube is filled with oil, the pulling of the cable will be easier, the electrical insulation will be better, and the thermal conductivity of heat from line losses will be better, i.e., a lower temperature of the conductor.
  • heat-tube size The choice of heat-tube size, cable, wire size, and insulation type and thickness depends on several considerations of design and construction of the complete assembly. A somewhat thicker insulation with more protective outer layers might be used. Also, a smaller, down to l /z-inch pipe size, possibly of heavier wall than 40 schedule pipe size would be indicated, depending on factors involved in the particular installation.
  • the heat-tubes of the prior art have, in some cases, been filled with an inert gas under a pressure which is indicated and I recorded to note any dimunitions of the pressure due to leaks.
  • the presently improved heat-tubes may likewise be so inspected and monitored for leaks by such a system, using inert L30 system of heat-tubes attached to oil-pipes has been found in those installations in which the heat-tube or heat-tubes have all joints made very tight, including those for inlet of electric wires.
  • the heat-tube is diagrammed as s simple tube 2 of any cross section and is not shown as connected to an oilpipe, as it normally would be.
  • the insulated conductor 3 passes through a vacuum tight joint of any standard type and is connected to an alternator 7, which supplies the AC.
  • Another electrical connection 13 from the alternator passes through another vacuum tight connection 20 to the inside of the heat-tube to complete the circuit through the inside wall of the heat-tube.
  • a tubular connection 9 from the heat-tube connects to a vacuum gauge 10 and a vacuum pump 11, which may be shut off from the heat-tube system by valve 12.
  • a vacuum is then produced inside the heat-tube by pump 11, and continuously monitored by watching pressure gauge 10.
  • An increase of pressure indicates a leak. It may be that an absolutely vacuumtight system cannot be secured, and some leakage maybe noted continuously, which must be taken care of intermittently or continuously by the vacuum pump. Any abrupt change in such more or less constant leakage is, however, immediately noticeable on the monitoring vacuum gauge. Steps are then taken to find and repair the leak.
  • Yet another system of monitoring the tightness of the heattube connections depends on keeping the tube around the insulated electric wire always under a substantial pressure with a low-viscosity oil.
  • the system supplying oil under pressure is then indicated by 11.
  • the oil gives additional insulation, aids in drawing the wire, and aids in transfer of heat from the internal conductor due to line losses. If the maintained oil pressure falls off of pressure gauge 10, a leak is indicated. If the leak is inwardly to the pipe and a petroleum oil, particularly a crude, is being transported, no damage is done, if the low-viscosity oil is a petroleum distillate.
  • a heat-tube such as this would be specified to be in those zones where ambient temperature was higher or lower, where more heat was lost due to the oil-pipe being buried in the ground, submerged in water, etc. If the same intensity of AC passed through each, the section where greater resistance was required would be placed where most heat was required.
  • the outer diameter of the heat-tube is not important if the wall thickness is more than about twice 6 the depth of penetration of the induction and magnetic effects. For most mild steels, 8 has been found to be about 0.04 inch.
  • FIG. 8 diagrams the installation of an oil-pipe of major length for which it is desired to keep the stations for supply of electrical energy to a minimum number. It has been found that the suitable or economical maximum length of a heat-tube system may be from 15 to 50 miles, depending on the various conditions peculiar to the particular installation. However, in long lines, periodically there must be a repeater" station, usually at distances apart equal to the length of a heat-tube.
  • the repeater stations may be at twice the distance apart as the economical maximum length of the heat-tube.
  • a pair of heat-tubes, 2" and 2 are placed in opposite lengths from one supply of AC.
  • the two electric wires inside the heat-tubes, 2 and 2" run in opposite directions, and are each attached to a terminal of the AC, while the terminals connect to the return legs of the circuit from the near end of the heat-tube, usually but 'not necessarily from a point on its, inner surface.
  • connection are made from another pair of heat-tubes, one of which is 2.
  • the ends of heat-tubes 2' and 2" back up to each other.
  • Heat-tubes 2" and 2"" back up to each other; and 2" would be one of a pair serviced by a repeater station not shown on the right.
  • the greatest heat requirement is at the startup after a shutdown, with the pipe filled with cold oil. If storage tanks are available at each station, the oil-pipe on the downstream side is supplied with the full AC capacity of the alternator. As one heat-tube may not take the increased input of AC a second heat-tube is incorporated in the pipeline to give double normal. heat for this start up. (It is also a spare unit in case of damage to the first.) After the downstream line is heated, it is put in service to pipe oil into the storage tank, the upstream pipe is then heated with as much of the total capacity as can be afforded, while the section beyond is being heated from the next alternator station. Thus, the entire line is started progressively.
  • 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;
  • a source of AC having a first terminal and a second terminal
  • 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;
  • 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;
  • 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 tto encompass the said external surface between.
  • 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 innersurface of a strip of steel which covers said part of the external surface of the transport-pipe;
  • At least a part .of the external surface of said transportpipe 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 heattube; and I 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.
  • 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.
  • 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.
  • 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;
  • 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;
  • 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.
  • 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;
  • each heat-tube comprises a plurality of sections arranged end-to-end and each section having a different internal perimeter.
  • a system for heating materials being transported comprising:
  • 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;

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Electromagnetism (AREA)
  • General Induction Heating (AREA)
  • Pipeline Systems (AREA)
US3617699D 1969-03-10 1969-03-10 A system for electrically heating a fluid being transported in a pipe Expired - Lifetime US3617699A (en)

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US80571869A 1969-03-10 1969-03-10

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US3706872A (en) * 1970-05-15 1972-12-19 William J Trabilcy System for electrically heating fluid-conveying pipe lines and other structures
US3777117A (en) * 1969-03-10 1973-12-04 D Othmer Electric heat generating system
US3815623A (en) * 1971-11-04 1974-06-11 Farmer Mold & Machine Works Molten metal delivery system
US3974398A (en) * 1971-01-18 1976-08-10 Othmer Donald F Wire and steel tube as AC cable
US3975617A (en) * 1971-01-18 1976-08-17 Othmer Donald F Pipe heating by AC in steel
US4134002A (en) * 1975-11-21 1979-01-09 Stanford George H Down spouts provided with heating elements
WO1982000746A1 (en) * 1980-08-20 1982-03-04 D Blackmore Skin effect heat generating unit having convective and conductive transfer of heat
US4366356A (en) * 1980-03-18 1982-12-28 Chisso Corporation Compact induced current heat-generating pipe
US4408117A (en) * 1980-05-28 1983-10-04 Yurkanin Robert M Impedance heating system with skin effect particularly for railroad tank cars
US4423311A (en) * 1981-01-19 1983-12-27 Varney Sr Paul Electric heating apparatus for de-icing pipes
WO1990010817A1 (en) * 1989-03-16 1990-09-20 Urpo Vainio Oy Electric current heater for pipes
US5241147A (en) * 1988-10-31 1993-08-31 Den Norske Stats Oljeselskap A.S. Method for heating a transport pipeline, as well as transport pipeline with heating
US5390961A (en) * 1993-04-28 1995-02-21 Thermon Manufacturing Company Dual wall thermally insulated conduit including skin effect heat tracing pipes
WO1997036063A1 (en) * 1996-03-25 1997-10-02 Sumner Glen R Heated offshore pipeline and method of manufacturing
US5871042A (en) * 1997-11-04 1999-02-16 Teradyne, Inc. Liquid cooling apparatus for use with electronic equipment
US6024842A (en) * 1998-03-06 2000-02-15 Komax Systems, Inc. Distillation column device
US6031972A (en) * 1998-01-19 2000-02-29 Industrial Engineering & Equipment Company Impedance heating system
US6049657A (en) * 1996-03-25 2000-04-11 Sumner; Glen R. Marine pipeline heated with alternating current
US20020072515A1 (en) * 1995-12-01 2002-06-13 Suntory Limited Pyrroloazepine derivatives
US6617556B1 (en) 2002-04-18 2003-09-09 Conocophillips Company Method and apparatus for heating a submarine pipeline
US20030175568A1 (en) * 2000-07-28 2003-09-18 Joe Cargnelli Apparatus for humidification and temperature control of incoming fuel cell process gas
US20040144438A1 (en) * 2003-01-24 2004-07-29 Thompson Alvin Dean Heated drain line apparatus
US6787254B2 (en) 2000-07-28 2004-09-07 Hydrogenics Corporation Method and apparatus for humidification and temperature control of incoming fuel cell process gas
US20050183773A1 (en) * 2004-02-23 2005-08-25 Ross Sinclaire Multi-story water distribution system
US20060291837A1 (en) * 2005-06-10 2006-12-28 Steve Novotny Heat generation system
DE202007013054U1 (de) 2007-09-18 2009-02-19 Thomas, Karl-Wilhelm, Dipl.-Ing. Skineffekt-Rohrleitungsbeheizung
US20090214196A1 (en) * 2008-02-15 2009-08-27 Jarle Jansen Bremnes High efficiency direct electric heating system
US20110056580A1 (en) * 2008-03-31 2011-03-10 Airbus Operations Gmbh Climate Tube, Particularly For Airplanes
US20110150440A1 (en) * 2009-12-17 2011-06-23 Lord Ltd. Lp Dual wall axial flow electric heater for leak sensitive applications
US20110286728A1 (en) * 2010-05-24 2011-11-24 Xiotin Industry Ltd. Heater and electric instant water heater
US20120145702A1 (en) * 2009-12-15 2012-06-14 The Boeing Company Smart heating blanket
US20120227951A1 (en) * 2008-12-06 2012-09-13 Thomas William Perry Heat transfer between tracer and pipe
US20130192677A1 (en) * 2012-01-31 2013-08-01 Davor Kriz Heating device for valve to prevent internal accumulation of condensate
US20130213487A1 (en) * 2012-02-22 2013-08-22 Yuzhi Qu Pipeline heating technology
US8833440B1 (en) * 2013-11-14 2014-09-16 Douglas Ray Dicksinson High-temperature heat, steam and hot-fluid viscous hydrocarbon production and pumping tool
US20140326504A1 (en) * 2012-01-11 2014-11-06 Halliburton Energy Services, Inc. Pipe in pipe downhole electric heater
US20150223638A1 (en) * 2014-02-11 2015-08-13 Adco Industries - Technologies, L.P. Roller Grill
DE102014002517A1 (de) * 2014-02-22 2015-08-27 Klaus-Dieter Kaufmann Anordnung und Verfahren zur Beheizung von Pipelines für den Fluidtransport
US20150291283A1 (en) * 2014-04-15 2015-10-15 The Boeing Company Monolithic part and method of forming the monolithic part
US9198234B2 (en) 2012-03-07 2015-11-24 Harris Corporation Hydrocarbon fluid pipeline including RF heating station and related method
US20190208582A1 (en) * 2014-10-09 2019-07-04 Nvent Services Gmbh Voltage-Leveling Heater Cable
US10473381B2 (en) 2016-10-05 2019-11-12 Betterfrost Technologies Inc. High-frequency self-defrosting evaporator coil
CN112628112A (zh) * 2020-12-23 2021-04-09 襄阳航顺航空科技有限公司 一种涡轮增压器测试机用供油装置
WO2021091584A1 (en) * 2019-11-08 2021-05-14 Att Technology, Ltd. Method for low heat input welding on oil and gas tubulars
US20210148604A1 (en) * 2018-04-03 2021-05-20 I.R.C.A. S.P.A. Industria Resistenze Corazzate E Affini Electric heater
US11022254B2 (en) * 2014-09-17 2021-06-01 Exxonmobil Upstream Research Company Thermally induced recirculation mixing for gel strength mitigation
US20220113095A1 (en) * 2020-10-08 2022-04-14 Controls Southeast, Inc. Adjustable heat transfer element
CN114575784A (zh) * 2022-03-14 2022-06-03 东北石油大学 一种高真空壁绝热管柱及其制备方法
CN114857394A (zh) * 2022-01-26 2022-08-05 石晓 精准控制管道设备系统内温度的传热装置

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DE2218796B2 (de) * 1972-04-18 1974-02-07 Bosch-Siemens-Hausgeraete Gmbh, 7000 Stuttgart Durchlauferhitzer
JPS5852315B2 (ja) * 1979-02-21 1983-11-21 チッソエンジニアリング株式会社 表皮電流加熱パイプライン
GB2262693B (en) * 1991-12-17 1995-06-07 Electricity Ass Tech Induction heater
DE19525200A1 (de) * 1995-07-11 1997-01-16 Abb Patent Gmbh Transportrohr
DE19616354C2 (de) * 1996-04-24 2003-07-24 Eberspaecher J Gmbh & Co Rohrleitungsstück mit elektrischer Leitung
CN102767648B (zh) * 2012-05-10 2014-09-10 上海蓝翎管业科技有限公司 设有有机纤维增强层的pvc水管
CN108286634A (zh) * 2016-12-30 2018-07-17 长春北方化工灌装设备股份有限公司 一种用于柔性管道内部的加热装置
CN108344171B (zh) * 2018-02-08 2024-03-19 厦门阿玛苏电子卫浴有限公司 一种防漏电的电热水器
CN110332413B (zh) * 2019-08-06 2022-02-08 寿光市鸿达化工有限公司 管道加热设备
CN110529739B (zh) * 2019-09-06 2022-03-15 鞍钢化学科技有限公司 易凝固介质管道加热方法及加热装置

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US2543882A (en) * 1949-03-05 1951-03-06 Reuben S Tice Electrical heating system for damp places
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Cited By (78)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3777117A (en) * 1969-03-10 1973-12-04 D Othmer Electric heat generating system
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
US3975617A (en) * 1971-01-18 1976-08-17 Othmer Donald F Pipe heating by AC in steel
US3815623A (en) * 1971-11-04 1974-06-11 Farmer Mold & Machine Works Molten metal delivery system
US4134002A (en) * 1975-11-21 1979-01-09 Stanford George H Down spouts provided with heating elements
US4334142A (en) * 1979-01-04 1982-06-08 Douglas Blackmore Skin effect pipe heating system utilizing convective and conductive heat transfer
US4366356A (en) * 1980-03-18 1982-12-28 Chisso Corporation Compact induced current heat-generating pipe
US4408117A (en) * 1980-05-28 1983-10-04 Yurkanin Robert M Impedance heating system with skin effect particularly for railroad tank cars
WO1982000746A1 (en) * 1980-08-20 1982-03-04 D Blackmore Skin effect heat generating unit having convective and conductive transfer of heat
US4423311A (en) * 1981-01-19 1983-12-27 Varney Sr Paul Electric heating apparatus for de-icing pipes
US5241147A (en) * 1988-10-31 1993-08-31 Den Norske Stats Oljeselskap A.S. Method for heating a transport pipeline, as well as transport pipeline with heating
WO1990010817A1 (en) * 1989-03-16 1990-09-20 Urpo Vainio Oy Electric current heater for pipes
US5390961A (en) * 1993-04-28 1995-02-21 Thermon Manufacturing Company Dual wall thermally insulated conduit including skin effect heat tracing pipes
US20020072515A1 (en) * 1995-12-01 2002-06-13 Suntory Limited Pyrroloazepine derivatives
GB2326226A (en) * 1996-03-25 1998-12-16 Glen R Sumner Heated offshore pipeline and method of manufacturing
US6049657A (en) * 1996-03-25 2000-04-11 Sumner; Glen R. Marine pipeline heated with alternating current
GB2326226B (en) * 1996-03-25 2000-11-22 Glen R Sumner Heated offshore pipeline and method of manufacturing
WO1997036063A1 (en) * 1996-03-25 1997-10-02 Sumner Glen R Heated offshore pipeline and method of manufacturing
US5871042A (en) * 1997-11-04 1999-02-16 Teradyne, Inc. Liquid cooling apparatus for use with electronic equipment
US6031972A (en) * 1998-01-19 2000-02-29 Industrial Engineering & Equipment Company Impedance heating system
US6024842A (en) * 1998-03-06 2000-02-15 Komax Systems, Inc. Distillation column device
US7051801B1 (en) 2000-07-28 2006-05-30 Hydrogenics Corporation Method and apparatus for humidification and temperature control of incoming fuel cell process gas
US20030175568A1 (en) * 2000-07-28 2003-09-18 Joe Cargnelli Apparatus for humidification and temperature control of incoming fuel cell process gas
US7261150B2 (en) * 2000-07-28 2007-08-28 Hydrogenics Corporation Apparatus for humidification and temperature control of incoming fuel cell process gas
US6787254B2 (en) 2000-07-28 2004-09-07 Hydrogenics Corporation Method and apparatus for humidification and temperature control of incoming fuel cell process gas
US7052791B2 (en) 2000-07-28 2006-05-30 Hydrogenics Corporation Apparatus for humidification and temperature control of incoming fuel cell process gas
US6617556B1 (en) 2002-04-18 2003-09-09 Conocophillips Company Method and apparatus for heating a submarine pipeline
US6810916B2 (en) * 2003-01-24 2004-11-02 Dt Search & Designs, Llc Heated drain line apparatus
US20040144438A1 (en) * 2003-01-24 2004-07-29 Thompson Alvin Dean Heated drain line apparatus
US20050183773A1 (en) * 2004-02-23 2005-08-25 Ross Sinclaire Multi-story water distribution system
US7308906B2 (en) * 2004-02-23 2007-12-18 Ross Sinclaire Multi-story water distribution system
US20060291837A1 (en) * 2005-06-10 2006-12-28 Steve Novotny Heat generation system
US7606475B2 (en) * 2005-06-10 2009-10-20 Steve Novotny Heat generation system
DE202007013054U1 (de) 2007-09-18 2009-02-19 Thomas, Karl-Wilhelm, Dipl.-Ing. Skineffekt-Rohrleitungsbeheizung
US20090214196A1 (en) * 2008-02-15 2009-08-27 Jarle Jansen Bremnes High efficiency direct electric heating system
US20110056580A1 (en) * 2008-03-31 2011-03-10 Airbus Operations Gmbh Climate Tube, Particularly For Airplanes
US8973619B2 (en) * 2008-03-31 2015-03-10 Airbus Operations Gmbh Climate tube, particularly for airplanes
US8899310B2 (en) * 2008-12-06 2014-12-02 Qmax Industries, Llc Heat transfer between tracer and pipe
US10520257B2 (en) 2008-12-06 2019-12-31 Controls Southeast, Inc. Heat transfer between tracer and pipe
US9841239B2 (en) 2008-12-06 2017-12-12 Qmax Industries, Llc Heat transfer between tracer and pipe
US20120227951A1 (en) * 2008-12-06 2012-09-13 Thomas William Perry Heat transfer between tracer and pipe
US8469082B2 (en) * 2008-12-06 2013-06-25 3Ip, Llc Heat transfer between tracer and pipe
US20140083545A1 (en) * 2008-12-06 2014-03-27 Thomas William Perry Heat transfer between tracer and pipe
US20120145702A1 (en) * 2009-12-15 2012-06-14 The Boeing Company Smart heating blanket
US9174398B2 (en) * 2009-12-15 2015-11-03 The Boeing Company Smart heating blanket
US20110150440A1 (en) * 2009-12-17 2011-06-23 Lord Ltd. Lp Dual wall axial flow electric heater for leak sensitive applications
US8260126B2 (en) * 2009-12-17 2012-09-04 Lord Ltd., Lp Dual wall axial flow electric heater for leak sensitive applications
US20110286728A1 (en) * 2010-05-24 2011-11-24 Xiotin Industry Ltd. Heater and electric instant water heater
US11174706B2 (en) * 2012-01-11 2021-11-16 Halliburton Energy Services, Inc. Pipe in pipe downhole electric heater
US20140326504A1 (en) * 2012-01-11 2014-11-06 Halliburton Energy Services, Inc. Pipe in pipe downhole electric heater
US8783283B2 (en) * 2012-01-31 2014-07-22 Control Components, Inc. Heating device for valve to prevent internal accumulation of condensate
US20130192677A1 (en) * 2012-01-31 2013-08-01 Davor Kriz Heating device for valve to prevent internal accumulation of condensate
US20130213487A1 (en) * 2012-02-22 2013-08-22 Yuzhi Qu Pipeline heating technology
US9198234B2 (en) 2012-03-07 2015-11-24 Harris Corporation Hydrocarbon fluid pipeline including RF heating station and related method
US20160040817A1 (en) * 2012-03-07 2016-02-11 Harris Corporation Hydrocarbon fluid pipeline including rf heating station and related methods
US10458588B2 (en) * 2012-03-07 2019-10-29 Harris Corporation Hydrocarbon fluid pipeline including RF heating station and related methods
US8833440B1 (en) * 2013-11-14 2014-09-16 Douglas Ray Dicksinson High-temperature heat, steam and hot-fluid viscous hydrocarbon production and pumping tool
US20150223638A1 (en) * 2014-02-11 2015-08-13 Adco Industries - Technologies, L.P. Roller Grill
US9545172B2 (en) * 2014-02-11 2017-01-17 Adco Industries-Technologies, L.P. Roller grill
US20170105571A1 (en) * 2014-02-11 2017-04-20 Raymond E. Davis Roller grill
DE102014002517A1 (de) * 2014-02-22 2015-08-27 Klaus-Dieter Kaufmann Anordnung und Verfahren zur Beheizung von Pipelines für den Fluidtransport
US10065370B2 (en) 2014-04-15 2018-09-04 The Boeing Company Method of making a monolithic part
US9452840B2 (en) * 2014-04-15 2016-09-27 The Boeing Company Monolithic part and method of forming the monolithic part
US20150291283A1 (en) * 2014-04-15 2015-10-15 The Boeing Company Monolithic part and method of forming the monolithic part
US11022254B2 (en) * 2014-09-17 2021-06-01 Exxonmobil Upstream Research Company Thermally induced recirculation mixing for gel strength mitigation
US11503674B2 (en) * 2014-10-09 2022-11-15 Nvent Services Gmbh Voltage-leveling heater cable
US20190208582A1 (en) * 2014-10-09 2019-07-04 Nvent Services Gmbh Voltage-Leveling Heater Cable
US10473381B2 (en) 2016-10-05 2019-11-12 Betterfrost Technologies Inc. High-frequency self-defrosting evaporator coil
US20210148604A1 (en) * 2018-04-03 2021-05-20 I.R.C.A. S.P.A. Industria Resistenze Corazzate E Affini Electric heater
US11859866B2 (en) * 2018-04-03 2024-01-02 I.R.C.A. S.P.A. Industria Resistenze Corazzate E Affini Electric heater
WO2021091584A1 (en) * 2019-11-08 2021-05-14 Att Technology, Ltd. Method for low heat input welding on oil and gas tubulars
US11938572B2 (en) 2019-11-08 2024-03-26 Att Technology, Ltd. Method for low heat input welding on oil and gas tubulars
US20220113095A1 (en) * 2020-10-08 2022-04-14 Controls Southeast, Inc. Adjustable heat transfer element
CN112628112A (zh) * 2020-12-23 2021-04-09 襄阳航顺航空科技有限公司 一种涡轮增压器测试机用供油装置
CN114857394A (zh) * 2022-01-26 2022-08-05 石晓 精准控制管道设备系统内温度的传热装置
CN114575784B (zh) * 2022-03-14 2023-12-26 东北石油大学 一种高真空壁绝热管柱及其制备方法
CN114575784A (zh) * 2022-03-14 2022-06-03 东北石油大学 一种高真空壁绝热管柱及其制备方法

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BE747115A (fr) 1970-08-17
AU1238170A (en) 1971-09-16
GB1302622A (zh) 1973-01-10
CH542399A (de) 1973-09-30
FR2037832A5 (zh) 1970-12-31
AT309613B (de) 1973-08-27
CH587438A5 (zh) 1977-04-29

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