Abstract: An induction heating system includes an induction heating head assembly configured to move relative to a workpiece. The induction heating system may also include a temperature sensor assembly configured to detect a temperature of the workpiece and/or a travel sensor assembly configured to detect a position, movement, or direction of movement of the induction heating head assembly relative to the workpiece, and to transmit feedback signals to a controller configured to adjust the power provided to the induction heating head assembly by a power source based at least in part on the feedback signals. In certain embodiments, the induction heating system may also include a connection box configured to receive the feedback signals, to perform certain conversions of the feedback signals, and to provide the feedback signals to the power source.

Abstract: Methods and apparatus for induction heating are disclosed. An example induction heating cable assembly includes: a first group of one or more cables extending substantially in parallel; a second group of one or more cables extending substantially in parallel, the first group of cables in parallel with the second group of cables; and an insulation layer configured to insulate the first group of cables and the second group of cables from electrical contact, the insulation layer configured to group the first group of cables, to group the second group of cables, and to extend between the first group and second groups of cables, in which the first group of cables, the second group of cables, and the insulation layer are conformable to enable conformance of the induction heating cable assembly to a workpiece to be heated via the induction heating cable assembly.

Abstract: An induction heating coil (3) has a primary coil (4) to which electric power is supplied and a ring-shaped secondary coil (5) forming a closed circuit. The primary coil (4) has a base-side portion that covers an outer periphery of the secondary coil (5) and a distal-side portion extending from the base-side portion in the center axis direction of the secondary coil (5) in a state in which the base-side portion covers the secondary coil (5). The opening width of the base-side portion is greater than the opening width of the distal-side portion. The secondary coil (5) is provided such that it can be inserted into and removed from the inside of the primary coil (4) from the base-side portion of the primary coil (4).

Abstract: Provided is apparatus (20) for heating a portion of subsea pipeline (10). The apparatus (20) generally comprises at least one electrical conductor (22), and a deployment mechanism (24) which is configured to operatively support a length of said electrical conductor (22) in a looped manner. In addition, the deployment mechanism (24) is further configured to deploy the looped conductor (26) circumferentially about at least a portion of the pipeline (10). When the conductor (22) is connected to a suitable power supply, the looped conductor (26) is configured to operatively induce an alternating magnetic field within the portion of the pipeline (10) in order to generate heat therein through induction heating.

Abstract: A kit for fusing piping includes a plurality of couplings, each coupling having a susceptor layer concentric with a weld zone. A control unit provides a current to a wand with a handle for gripping by a user. The handle has opposing jaws mounted on the distal end, each jaw including an arcuate conductor such that the arcuate conductors form a circular inner diameter when the jaws make contact. A lever system couples to the distal end for opening and closing the jaws. The lever system includes a spring for selectively biasing the lever system in a latched position with jaws closed and an open position with the jaws open. Each coupling is sized such that the jaws will only close about the weld zone. The arcuate conductors create a fuse zone about the susceptor layer and the spring is outside the fuse zone.

Abstract: Methods, systems, apparatus and machine readable media are disclosed to reduce biological carryover. An example method includes generating an alternating electromagnetic field and introducing an aspiration and dispense device into the electromagnetic field. The example method also includes inductively heating the aspiration and dispense device with the electromagnetic field to at least one of denature or deactivate at least one of a protein or a biological entity on a surface of the aspiration and dispense device.

Abstract: A method for making a tube is described in which a multi-layer billet is extruded to provide a tube having a wall comprising an inner layer metallurgically bonded to an outer layer.

Abstract: This invention relates to the design of a process by intermittent dielectric heating combined with a recycling system. This process consists in subjecting reagents to electromagnetic waves selected in the frequencies ranging between 300 GHz and 3 MHz intermittently using a recycling system. This process enables the treatment of oils that are hardly absorbent as well as great investment savings. This process enables operation on different scales, whether in laboratories, on a semi-industrial or industrial scale, without forfeiting the advantages of continuous dielectric heating.

Abstract: The invention includes systems and methods for heating a fluid and transporting the fluid at an elevated temperature. The system includes a fiber reinforced spoolable pipe. This spoolable pipe may include an inner layer, at least one reinforcing layer, at least one heating element, and at least one insulation layer. The heating element may be located external to the inner layer. The invention also includes methods of deploying and rehabilitating a spoolable pipe for transporting a fluid at elevated temperature.

Abstract: The induction coil unit for heating a component that is rotationally symmetrical relative to an axis (7), in particular a tool holder (5), comprises a plurality of coils (19) arranged about the axis (7) of the tool holder (5) with pole elements, which are movable radially with respect to the axis (7), which are connected to one another by a common yoke ring (17). Upon excitation of the coils (19) with alternating current, the latter produce a magnetic flux running in the peripheral direction in the tool holder (5) for the inductive heating of the tool holder (5). The induction coil unit (1) can be moved in an oscillating manner by means of a drive (87) in the direction of the axis (7), the pole elements (21) moving in an oscillating manner along the tool holder (5). An induction coil unit of this type is in a position to heat a comparatively large region of the tool holder (5) despite a comparatively small energy requirement and comparatively small dimensions.

Abstract: The induction coil unit for heating a component which is rotationally symmetrical relative to an axis, in particular a tool holder (5), comprises a plurality of coils (19) arranged about the axis (7) of the tool holder (5), with pole elements (2), which are movable radially with respect to the axis (7), of which pole elements each one consists of a stack of pole rods (25) that can be moved relative to one another. A yoke ring (17) connects the pole elements, which, when the coils (19) are excited by alternating current in the tool holder (5), produce a magnetic flux running in the peripheral direction to inductively heat the tool holder (5). The pole rods (25) of each pole element (21) can be moved jointly by means of pinion rollers (29), wherein, however, slide couplings or the like are provided in the drive force transmission path between the individual pole rods so that the pole elements (21) can adapt to different contours of the tool holder (5).

Abstract: A magnetic flux concentrator is used to control the end heating of a tubular material in an electric induction heat treatment process. The magnetic flux concentrator may consist of fixed elements, or a combination of fixed and moveable elements to accommodate end heating of tubular materials having different dimensions or material properties.

Abstract: A grounded electrical circuit in a heated hose is provided. In one embodiment, the heated hose assembly includes: a flexible hose body; a first and a second heating wires and a hose ground wire each extending longitudinally and parallel to an axis of the hose body and within an inner wall; a first fluid coupling provided on the first end portion of the flexible hose body, the first fluid coupling comprising a stem inserted into the flexible hose body and radially clamping an end of the hose ground wire against an inner surface of the inner wall, such that a contact between the first fluid coupling and the end of the hose ground wire grounds the hose ground wire; a power cord electrically connected to the first and second heating wires and to the hose ground wire; and a thermostat electrically connected to the first and second heating wires.

Abstract: Methods and systems for providing an impedance heat transfer fluid heating system in association with a parabolic trough solar concentrator are provided. The system includes an intermediate terminal connector that electrically interconnects a receiver tube of the parabolic trough solar concentrator to a power supply. The intermediate terminal connector can include a pair of plates running parallel to the receiver tube. The system additionally includes a pair of end terminal connectors. Each end terminal connector features a receiver tube plate having an aperture that completely surrounds the receiver tube assembly pipe. The end terminal connectors can additionally include a terminal connector extension that is at an angle to the receiver tube plate. A current return conductor extends between an end terminal connector and the power supply. The current return conductor is supported by the collector frame or structure and/or a receiver tube support structure.

Abstract: A water-transporting line includes an integrated heater system for protection against frost and the appropriate connection, attachment and control elements. A self-heating water conduit segment is provided that has an integrated heating device, which device encloses the outer surface of the water conduit segment. The various segments may be connected mechanically and electrically using corresponding connecting elements.

Abstract: A high-frequency induction heating apparatus is provided with a high-frequency oscillation apparatus, a heating coil, a high-frequency transformer and the like, the heating coil has a first coil through which prescribed current outputted by the high-frequency oscillation apparatus is flown, a second coil through which current different from the predetermined current is flown by the high-frequency transformer, and the first coil heats a trunk part and a bottom side part of the can body, and the second coil heats the trim side part of the can body.

Abstract: A steam generation device and a method for generating steam using the device are disclosed. The device includes a fluid circulation pipe containing electrically and thermally conductive material, and at least one inductive cable made from an electrically conductive material wound around the pipe. The device and method allow for improved steam generation.

Abstract: The invention relates to an induction annealing apparatus able to anneal cartridge cases to improve their reusability. The apparatus may comprise a power supply unit and a plurality of annealing units, each comprising a magnetic core having ends separated by an air gap. An induction coil is wound around the magnetic core to generate a magnetic field in the air gap. A cartridge case holder holds the cartridge case such that the neck of the cartridge case is positioned in one of the air gaps. The power supply unit selectively connects to the annealing units to supply power for a predetermined length of time, and the size of the air gap of the magnetic cores of each of the annealing units may differ. In other embodiments, the size of the air gap may be adjustable, a temperature sensor or a ferrite stake may be provided.

Abstract: A method and apparatus for annealing cylindrical cases for ammunition cartridges or other tubular casings is provided. In one embodiment, a case annealing apparatus is provided. The case annealing apparatus includes a base, a feeding device having a first end tapering to a second end that is coupled to the base, a rotatable feed wheel assembly disposed adjacent a second end of the feeding device, a linear slide mechanism disposed adjacent the rotatable feed wheel assembly defining a portion of a case receiving region, and a heating device disposed adjacent the case receiving region, the heating device operable to heat a portion of a case retained in the case receiving region.

Abstract: Embodiments of the invention provide a system and method for induction heating a helical rotor of a progressing cavity pump in order to reduce the surface roughness of the rotor. In order to heat the rotor most evenly, it is desired to space the coil as closely around the rotor as possible. The invention provides a mechanism for threading the helical rotor through an induction coil having an interior diameter which is less than the major diameter of the rotor. The induction coil may include one loop and overlapping ends. The rotor to be heated is rotated about its longitudinal axis and advanced axially through the coil as it rotates. The axial speed and rotational speed are synchronized so that the rotor moves one pitch through the coil for each complete rotation.

Abstract: A device for high efficiency induction heating or direct electrical heating, DEH, of a number, M, M?[1, N of a group of parallel subsea pipelines N, where N?[2, ?, and where a number of conductor cables, W, supplies electrical power from at least one top side power supply to M of the parallel subsea pipelines N, wherein the number of electric conductors, W, from the at least one top side power supply connected to the M pipelines is defined to be in the group W?[N, N+1], where N, W and M are natural numbers.

Abstract: A heating device for heating a hollow component may include at least one inner induction coil and at least one outer induction coil, each configured to be heated. At least one element may be configured to influence a magnetic field formed between the inner and the outer induction coil during the operation of the heating device. The element may be arranged between the inner and the outer induction coils. Regions of the hollow component may be thinner and the thinner regions may be configured to heat more quickly than the remaining thicker regions. The thinner and thicker regions of the component may allow even heating of the component to be achieved.

Abstract: An induction heating apparatus for use in pre-heating pipe joints. The induction heating apparatus comprises a frame for applying around the pipe joint, and an induction heating coil made from Litz cable wires.

Abstract: A fixing device includes a heating rotating member that generates heat by induction heating; an induction coil that generates magnetic flux for induction heating; and a magnetic member core section forming a magnetic path and including a first core section, a second core section, a magnetic flux shielding member, and third core sections. The magnetic flux shielding member is disposed at a side of an end portion of the first core section opposite to the second core section and separated from the end portion, and disposed at a position that is separated from the outer surface of the heating rotating member by a separation distance. The third core sections are disposed at a side of the magnetic flux shielding member facing the end portion of the first core section. At least one of the third core sections is movable to a first position and to a second position.

Abstract: A device (10-10?), (11-11?) for the localized heating of parts of metal pipes (12) connected to each other and of parts of primary plastic coating (16?-18?) of the same pipes, all to be coated with protective material, comprises a spiral-wise development winding consisting of one or more coils (20) and of annular means that are arranged within and coaxially to said coil (20), at the parts of primary plastic coating (16?-18?), and that surround each one of said pipes (12) for heating by induction a zone (14) without primary plastic coating and for indirectly heating, by irradiation, end portions of the same provided with plastic coating (16?-18?) contiguous to said zone (14).

Abstract: Methods, systems, apparatus and machine readable media are disclosed to reduce biological carryover. An example method includes generating an alternating electromagnetic field and introducing an aspiration and dispense device into the electromagnetic field. The example method also includes inductively heating the aspiration and dispense device with the electromagnetic field to at least one of denature or deactivate at least one of a protein or a biological entity on a surface of the aspiration and dispense device.

Abstract: An induction heating device for heating the surface of a pipe or pipeline comprises an induction heating head (100) having a main body (110) and a handle portion (130) extending therefrom. The main body is configured to be removably secured to the surface of the pipe or pipeline and includes a first magnet (121) disposed in a first end (111) and a second magnet (122) disposed in a second end (112). The main body further includes an induction heating portion (150) disposed in a central portion (113) of the main body between the first and second magnets (121, 122). The handle portion includes a grip area extended from the main body.

Abstract: A flexible, electrically heatable hose having an elongated electrical conductor which extends in the helical shape in the hose direction is illustrated and described. The object of providing a flexible, electrically heatable hose in which uniform heating over the hose length is ensured even in the event of major deformation of the hose, is achieved by a hose which has an elongated electrical conductor which extends in a helical shape in the hose direction, wherein the electrical conductor is embedded in a braid. In this case, the braid has first and second strands, wherein the first strands extend in a helical shape in the hose direction in the same winding direction as the electrical conductor, and the second strands extend in a helical shape in the hose direction in the opposite winding direction to the electrical conductor. The pitch angle of the electrical conductor, which extends in a helical shape in the hose direction, of the first strands and of the second strands is in this case between 50° and 80°.

Abstract: A portable pet warmer may include an outer cylinder and front and rear covers. An inner cylinder may be removably positioned within the outer cylinder. The inner cylinder remains spaced from the outer cylinder while the inner cylinder is positioned within the outer cylinder. A thermostat and a heating element may be located within the apparatus and adapted to be coupled to an external 115 volt alternating current power supply source. A mounting plate and retainer springs are used to hold the thermostat at a secure position during use while permitting easy access to the thermostat during maintenance. An internal power supply source providing a 12 volt direct current to the thermostat may further be electrically coupled to the circuit breaker.

Abstract: A device for clamping and unclamping of tools comprising a tool shaft, by which device a sleeve section (2) of a tool holder (1) comprising a centric receiver opening (4) for a shaft (5) of a rotation tool is inductively heated, which sleeve section retains the shaft (5) of the tool seated in the receiver opening (4) in a press fit, and releases it upon heat up, which device comprises an induction coil assembly with at least one induction coil (6), which can be fed by an electric current for heating the sleeve section (2), and which comprises a concentrator body (11), which is magnetically conductive and electrically nonconductive or substantially electrically nonconductive, which concentrates the magnetic flux of the induction coil (6) onto the portion of the tool side end of the sleeve section (2), wherein the concentrator body (11) supports an induction attachment (14) made of electrically conductive material.

Abstract: A sturdy electrical power circuit and grounding circuit for an electrically-heated hose is formed by electrically connecting a grounding wire extending along the length of the hose to a pair of fluid couplings fitted on opposite ends of the hose. The grounding wire is mechanically clamped against the inner wall of the hose by radially-outwardly expanding a tube on each coupling against the grounding wire to secure the grounding wire in place while simultaneously forming an electrical connection between the grounding wire and the fluid couplings.

Abstract: A water boiler includes a water storage tank, a heater, and a heat pipe unit. The water storage tank includes a heating room, an outer water storage room, and an inner water storage room between the heating room and the outer water storage room in a radial direction. Outside water flows from an inlet pipe to the outer water storage room, and water in the outer water storage room flows into the inner water storage room and the heating room for storage. The heater includes an induction coil. The heat pipe unit includes a plurality of heat-transfer pipes. An upper segment of each heat-transfer pipe is arranged in the heating room, while a lower segment of each heat-transfer pipe is received in the induction coil. When the induction coil turns ON, the heat-transfer pipes are heated to heat the water in the heating room.

Abstract: An apparatus and method for synthesizing nanostructures. In one embodiment, the apparatus includes a reactor having a reaction zone and a conductive susceptor positioned in the reaction zone. The method includes the steps of transporting a gas mixture having an aerosolized catalyst, a feedstock and a carrier gas into the reaction zone of the reactor, inductively heating the reaction zone, and regulating a flow rate of the gas mixture to allow the catalyst to spend a sufficient amount of time in the reaction zone for the growth of nanostructures.

Abstract: A fixing unit includes a rotatable fixing member and a rotatable pressure applying member. The rotatable fixing member has a heat generating layer to generate heat when subject to a magnetic flux. The rotatable pressure applying member contacts the rotatable fixing member and applies pressure to the fixing member. The rotatable fixing member and the rotatable pressure applying member form a nip therebetween, to which a recording medium is passed through to fix an image on the recording medium. The rotatable fixing member includes a magnetism regulating layer deformable when subject to pressure from the rotatable pressure applying member.

Abstract: An attenuating adaptor is proposed in the form of a sleeve (23) which is composed of non-ferromagnetic metal for insertion radially during operation between a holding section (11) (which is provided with a central holding opening (15) for holding a tool shank with a press fit) of a tool holder (1) and an induction coil arrangement (19) (which concentrically surrounds the holding section (11) in order to widen it thermally) of a shrinkage appliance (5) which feeds alternating current to the induction coil arrangement (19). The sleeve (23) can be provided with slots which pass through its wall and whose number, axial length and circumferential width influence the attenuating characteristics of the sleeve (23). Sleeves (23) of different sizes are provided for a set of different tool holders (1), and their attenuating characteristics are chosen such that all of the tool holders (1) in this set can be shrunk using one and the same setting of the shrinkage appliance (5).

Abstract: A method to manufacture tubing includes co-forming a base material strip and a liner material strip into a string of internally-lined tubing and joining edges of the base material strip to form a seam therebetween.

Abstract: A heating apparatus for heating a pipe prior to performing a welding operation, an interpass welding operation, or a hydrogen bake-out operation is provided. The heating apparatus comprises at least one heating collar placed on one side of a pipe weld joint and a control mechanism for controlling the thermal energy transferred from the heating apparatus to the pipe.

Abstract: A coupling for joining socket ends of multilayer tubing through electrofusion including a central body having opposing male ends. A core at least partially surrounds the central body and an outer layer encloses the core and central body. The outer layer defines a flange protruding radially outwardly from the central body, wherein the core includes a portion that extends radially outwardly through the flange and out of the flange so that the core can be directly heated by an external heating element.

Abstract: A device for clamping and unclamping of tools comprising a tool shaft, by which device a sleeve section (2) of a tool holder (1) comprising a centric receiver opening (4) for a shaft (5) of a rotation tool is inductively heated, which sleeve section retains the shaft (5) of the tool seated in the receiver opening (4) in a press fit, and releases it upon heat up, which device comprises an induction coil assembly with at least one induction coil (6), which can be fed by an electric current for heating the sleeve section (2), and which comprises a concentrator body (11), which is magnetically conductive and electrically nonconductive or substantially electrically nonconductive, which concentrates the magnetic flux of the induction coil (6) onto the portion of the tool side end of the sleeve section (2), wherein the concentrator body (11) supports an induction attachment (14) made of electrically conductive material.

Abstract: The present invention is related to a heated garden hose that has a flexible hose with an inlet and an outlet. The garden hose has an inlet coupler and an outlet coupler. A heating cable coupler is connected between the inlet and the outlet of the flexible hose. A heating cable has a first end with an electrical plug and extends through the heating cable coupler into the interior of the flexible hose. The heating cable is free floating inside the flexible hose. A thermostat, attached to the exterior portion of the heating cable, controls the heating cable and is designed to turn the heating cable off just above the freezing temperature of water. A clip is inserted into the flexible hose near the outlet to hold the heating cable inside of the flexible hose.

Abstract: An electrical energy generating apparatus includes a hollow pipe, permanent magnetic fluid held in the hollow pipe, a ferrite film wrapped around the hollow pipe, a heat source receiving device joined to a portion of the hollow pipe, and an induction coil wound around the hollow pipe; the induction coil being connected to a storage battery; in use, the heat source receiving device will receive heat energy from heat sources so that a portion of the fluid is heated, and temperature and pressure difference comes into existence in the fluid, and convection in the liquid happens to circulate the nano-chip permanent magnets around the hollow pipe; therefore, there is change in a magnetic field between the nano-chip permanent magnets and the ferrite film, and in turn the induction coil produces electric field, and electrical energy is produced, and next stored in the storage battery.

Abstract: A material composite has a part made from steel or a titanium-based material and a part made from a copper-based or aluminum-based material. The parts of the material composite are joined by way of an intermediate piece. The intermediate piece likewise comprises a region made from steel or a titanium-based material and a region made from a copper-based or aluminum-based material, which are connected by explosion welding. The parts of the material composite are connected to the regions of the intermediate piece which are in each case of the same type by means of a fusion or diffusion welding process.

Abstract: A flexible, electrically heatable hose having an elongated electrical conductor which extends in the helical shape in the hose direction is illustrated and described. The object of providing a flexible, electrically heatable hose in which uniform heating over the hose length is ensured even in the event of major deformation of the hose, is achieved by a hose which has an elongated electrical conductor which extends in a helical shape in the hose direction, wherein the electrical conductor is embedded in a braid. In this case, the braid has first and second strands, wherein the first strands extend in a helical shape in the hose direction in the same winding direction as the electrical conductor, and the second strands extend in a helical shape in the hose direction in the opposite winding direction to the electrical conductor. The pitch angle of the electrical conductor, which extends in a helical shape in the hose direction, of the first strands and of the second strands is in this case between 50° and 80°.

Abstract: Apparatus and method for inductive heating of a material located in a channel. In one embodiment, the heating assembly comprises an interior coil, an exterior sheath inductively coupled to the coil, a dielectric material disposed between the coil and sheath, and a conductor for supplying a signal to the coil to generate the magnetic flux for inductive heating of the sheath. The heating assembly is disposed in the material in the channel, and the magnetic flux generated by the coil may also inductively couple to the material in the channel. The material may be heated from a nonflowable to a flowable state, such as heating a metal or polymer plug formed in a melt channel of a molding apparatus.

Abstract: A fluid flow within a transportation pipeline is heated with low voltage, high current electrical energy induced into a conductive closed loop structure by one or more transformers. The closed loop structure is preferably a fluid transportation pipeline constructed of electrically conductive sections of pipeline. The amount of current induced is sufficient in relation to the inherent resistivity of the conductive sections to cause the generation of heat within the pipeline sections. By conductive and convective heat transfer, the heat induced into the pipeline structure is transferred to a fluid flow within the pipeline. The current is preferably an alternating current of frequency which causes a majority of the current to travel at or near the outer surfaces of the pipeline sections which increases the effective resistivity of the sections and heat generation therein.

Abstract: A sturdy electrical power circuit and grounding circuit for an electrically-heated hose is formed by electrically connecting a grounding wire extending along the length of the hose to a pair of fluid couplings fitted on opposite ends of the hose. The grounding wire is mechanically clamped against the inner wall of the hose by radially-outwardly expanding a tube on each coupling against the grounding wire to secure the grounding wire in place while simultaneously forming an electrical connection between the grounding wire and the fluid couplings.

Abstract: A processing apparatus subjects an object to be processed W to a heat process. The processing apparatus comprises: a processing vessel 22 capable of containing a object to be processed W; a coil part for induction heating 104 that is disposed outside the processing vessel 22; a radiofrequency power source 110 configured to apply a radiofrequency power to the coil part for induction heating 104; a gas supply part 90 configured to introduce a gas into the processing vessel 22; a holding part 24 configured to hold the object to be processed W in the processing vessel 22; and a induction heating element N that is inductively heated by a radiofrequency from the coil part for induction heating 104 so as to heat the object to be processed W. The induction heating element N is provided with a cut groove for controlling a flow of an eddy current generated on the induction heating element.

Abstract: Provided is a method of manufacturing a hollow power transmission shaft, which makes it possible to ensure stable quality even when there is a difference in wall thickness or hardening ratio along an axial direction thereof. A hollow shaft material (1?) is provided with, on an outer peripheral surface (1g) side thereof, for example, a movable induction heating coil (5) wrapped therearound. While a high-frequency current with a predetermined frequency is caused to flow through the induction heating coil (5), the induction heating coil (5) is axially moved to perform induction hardening of the hollow shaft material (1?) from the outer peripheral surface (1g) side.

Abstract: A device (1) for the induction hardening of components (2) which have a circular cross section, especially crankshafts, has two inductor half-shells (4, 5) arranged along a portion of the periphery of the component (2) to be hardened. At least one of the two inductor half-shells (4, 5) has only one inductor segment (6) through which current flows.

Abstract: The present invention relates to a method and apparatus for the prevention of fouling of process streams by the application of electric charge on process components. The electric charge may be attractive or repulsive to the foulants, they may be constant or variable and may be applied to any section of the process stream where convenient and wherein their preventive effects are optimized.