Abstract: Heating systems utilizing radio frequency (RF) energy and methods for using the same to rapidly and uniformly heat packaged articles moving through the system on one or more convey lines. These systems may be useful for a variety of processes, including the pasteurization or sterilization of packaged foodstuffs.

Abstract: A system and method for molding complex three-dimensional articles is disclosed. The system includes a mold for receiving an article made of at least one moldable material and, in one example, the article comprises at least one flat region and at least one radial region. The mold comprises an inner bladder that conforms to an inner surface of the article when pressurized and an outer mold that contacts an outer surface of the article. The system also includes an inner electrode spaced from an outer electrode, and a generator operable to generate an alternating electric field between the electrodes and across the article in the mold to obtain substantially even heating of the moldable material in the flat region and the radial region at the end of the heating cycle.

Abstract: A method of drying a ceramic formed body comprising the step of performing dielectric drying on an unfired honeycomb formed body formed with a ceramic material as a main raw material under a condition that a power density is 5 to 20 [kW/kg (water)].

Abstract: For the determination of the welding current to be used for the resistance welding of the overlap seam of container bodies, welding with a test body is carried out with a changing strength of welding current which in the test body produces a varying welding of the seam. The current strength varies from welding of this seam with a too high temperature to welding with a too low temperature. Along with this the welding current strength used in the welding is determined so that it is further determined at which point of the seam the welding has been accomplished and with what strength of welding current. By means of a mechanical and/or optical investigation of the welded seam it can then be easily determined where the seam has been correctly welded for the series production of container bodies from the same sheet material as the test bodies. When such a point or such a region of the seam is known the welding current used in the test welding can be taken as the welding current for serial production.

Abstract: Methods for annealing a metal foil layer to a glass layer, and/or for growing a native silicon layer in-situ therebetween. The annealing method includes applying an electrostatic (ES) field to the structure of the glass layer and the metal foil layer, with the metal foil layer positioned adjacent the glass layer, to electrostatically anneal them together. An electrostatic voltage of at least 1500 V may be applied. A seed crystal may be positioned between the glass layer and the metal foil layer prior to annealing. The method for growing a native metal (e.g., Si) layer in-situ may include applying an electrostatic voltage to the annealed structure with polarities reversed, at 1050° F. to 1100° F. Such conditions induce a redox reaction within the silica glass layer to reduce a portion of the silica, generating a layer of silicon between the glass layer and the metal foil layer.

Abstract: An oven for baking a thermally curable binder in a mat of mineral fibers, including plural compartments through which the mat of fibers passes successively, the mat being compressed and transported through the compartments by gas-permeable upper conveyors and lower conveyors, each compartment having a length along a direction of movement of the mat and including a mechanism introducing a hot air flow, located either below or above the fiber mat, and a mechanism extracting the air after having passed through the mat, respectively arranged either above or below the opposite face of the mat, so that the binder is progressively brought to a temperature higher than its curing temperature. In one compartment the mechanism introducing hot air includes air inlets that open partly on openings formed on a first lateral side of the compartment and partly on openings formed on the opposite lateral side of the compartment.

Abstract: A mandrel for use in welding an air mattress having a top layer, bottom layer and at least one baffle joining the top layer and bottom layer, the mandrel includes a central mounting block; a baffle locating pin on a top surface of the central mounting block for securing the baffle to the central mounting block; a conductive sealing surface positioned along an edge of the central mounting block; a stop block positioned on the top surface of the central mounting block adjacent the sealing surface; and a bumper mounted to the central mounting block.

Abstract: When applying a current to a plated steel plate, plating often biases. In the present invention, when applying a current, the current is applied with a flux guiding member arranged in proximity to a side surface of the plated steel plate. The direction of the magnetic flux at the side surface of the plated steel plate is corrected, and the bias of the plating is efficiently suppressed.

Abstract: A welding apparatus includes first and second die members opposing one another. The first and second die members include opposing respective first and second perimeter-welding electrodes and opposing respective first and second tube-welding electrodes. The first perimeter-welding electrode and first tube-welding electrode define a first welding surface. The second perimeter-welding electrode and second tube-welding electrode define a second welding surface. A single source of high frequency energy is electrically connected to the perimeter-welding electrodes and to the tube-welding electrodes. Dielectric material is selectively disposed on the first welding surface such that the material is disposed on some but not all the first welding surface for reducing a strength of a high frequency electric field between the first and second perimeter-welding electrodes as compared to a strength of the high frequency electric field between at least a portion of the first and second tube-welding electrodes.

Abstract: A method of forming a bag assembly by RF welding includes generating from a single source of RF energy a high frequency electric field having a first strength between tube-welding electrodes of opposing die members and a second strength less than said first strength between perimeter-welding electrodes of the opposing die members. Subjecting a tube assembly and corresponding portions of sheets surrounding the tube assembly to the high frequency electric field of said first strength for a predetermined amount of time to weld the sheets to a tube along a tube-weld. Corresponding portions of the sheets between the perimeter-welding electrodes are subjected to the high frequency electric field of said second strength for said predetermined amount of time to weld the sheets together along a bladder perimeter-weld. The subjecting steps are performed simultaneously so that the bag assembly is formed in one welding operation.

Abstract: Apparatus and methods for radiofrequency (RF) welding are disclosed. RF power delivered to a welding platen of the apparatus is capacitively split into first and second RF power components of different magnitudes. The power components are simultaneously delivered to respective first and second die members to conduct an RF welding operation.

Abstract: A method of and apparatus for forming a bag assembly by RF welding. A single source of RF energy is used to generate a high frequency electric field having a first strength between tube-welding electrodes of opposing die members and a second strength less than the first strength between perimeter-welding electrodes of the opposing die members. Respective portions of the bag assembly are subjected to this variable-strength field simultaneously so that the bag assembly is formed in one welding operation. Stand-offs are used in some embodiments to limit penetration of the electrodes into the weld areas.

Abstract: A loose mixture formed of one or more solid inert materials and a hardenable resin dissolved in an organic solvent, in particular the remainder of the initial mix used for the manufacture of conglomerate stone sheets, is rendered inert by means of dielectric heating at a frequency of less than 300 MHz. A plant for implements a method where a loose mixture is formed of one or more solid inert materials and a hardenable resin dissolved in an organic solvent, in particular the remainder of the initial mix used for the manufacture of conglomerate stone sheets, is rendered inert by means of dielectric heating at a frequency of less than 300 MHz.

Abstract: An apparatus for forming a bag assembly includes opposing die members. Each die member has a perimeter-welding portion for forming a perimeter-weld of the bag assembly and a tube-welding portion for forming a tube-weld of the bag. During operation, first the perimeter-welding and tube-welding portions weld the bag assembly simultaneously, then the perimeter-welding portions are moved to increase the distance between them. When the perimeter-welding portions are moved apart, welding by the perimeter-welding portions is generally suspended while welding by the tube-welding portions may continue.

Abstract: A radio frequency welding system for flexible work pieces having a top-side and an underside. The welding system includes a fixed weld platform, a mobile radio frequency welder adapted to move over the fixed weld platform, movable welding electrodes configured over the fixed weld platform and adapted to engage the underside of the flexible work pieces and movable grounding apparatus adapted to engage the fixed weld platform and the mobile radio frequency welder so as to provide a return radio frequency electrical circuit.

Abstract: Apparatus and methods for radiofrequency (RF) welding are disclosed. RF power delivered to a welding platen of the apparatus is capacitively split into first and second RF power components of different magnitudes. The power components are simultaneously delivered to respective first and second die members to conduct an RF welding operation.

Abstract: A raised platform for a microwave cooking of a food product that includes a support surface, a pair of generally rectangular legs depending from opposing sides of the support surface, a pair of leg extensions attached to each of the generally rectangular legs, and a susceptor surface disposed on the food product support surface for conducting heat to a food product thereon during microwave cooking. The raised platform can be converted between a collapsed configuration, where the legs are generally parallel to the support surface, and an expanded configuration, where the legs are generally perpendicular to the support surface.

Abstract: A method is provided for securing a fluid meter to a fluid collection bag. The method includes the steps of providing a meter ha6 ving a housing defining a fluid receptacle and at least one drain opening, providing a collection bag defining a fluid reservoir and having at least one inlet opening and securing the meter to the bag using an RF welding device to allow fluid communication between the fluid receptacle and the fluid reservoir. In one embodiment, the housing includes a raised surface positioned about the at least one drain opening to which the collection bag is welded.

Abstract: An RF welder, and a method of operation thereof, is disclosed that has circuitry that automatically affects system impedance so that, throughout the welding or embossing cycle, a generator is capable of delivering the same power to a die and fabric, and cabling is capable of dissipating a load that is less than a preselected amount.

Abstract: A clip on welder includes two pairs of opposed grippers defined by pivotally attached upper and lower frames for latching the welder to heat weldable material, such as a length of tubing, upon actuation of a start button by an operator; thereafter, the welder operates unattended. At least a jaw of a pair of jaws disposed intermediate the two pairs of grippers heats the material compressed and lodged therebetween to form a weld in or across the material. A source of gas, such as air, under pressure selectively connected to a bellows provides the power to pivot the upper and lower frames into gripping engagement with the material. A source of electrical signals provides the power to heat the material intermediate the pair of jaws. One or more thermocouples senses the heat of the jaws and generates signals used to control the application of power and to control cooling. After completion of the weld, cooling air is directed to the jaws until the thermocouple(s) signal(s) indicates a sufficiently low temperature.

Abstract: An RF welder is disclosed that has circuitry that automatically affects system impedance so that, throughout the welding or embossing cycle, a generator is capable of sending energy through die and fabric at a predetermined frequency and cabling is capable of dissipating a load that is less than a preselected amount.

Abstract: A clip on welder includes two pairs of opposed grippers defined by pivotally attached upper and lower frames for latching the welder to heat weldable material, such as a length of tubing, upon actuation of a start button by an operator; thereafter, the welder operates unattended. At least a jaw of a pair of jaws disposed intermediate the two pairs of grippers heats the material compressed and lodged therebetween to form a weld in or across the material. A source of gas, such as air, under pressure selectively connected to a bellows provides the power to pivot the upper and lower frames into gripping engagement with the material. A source of electrical signals provides the power to heat the material intermediate the pair of jaws. One or more thermocouples senses the heat of the jaws and generates signals used to control the application of power and to control cooling. After completion of the weld, cooling air is directed to the jaws until the thermocouple(s) signal(s) indicates a sufficiently low temperature.

Abstract: Dielectric welding apparatus has opposed electrodes that can be engaged on either side of a product to be welded and a dielectric welding power supply that supplies welding potentials to the electrodes. The apparatus includes electrically insulating buffer material adjacent to at least one of the electrodes. A recess formed in a surface of the buffer material receives an end of an electrically-conductive member in the product. The buffer material prevents arcing between the electrodes and the electrically-conductive member.

Abstract: A clip on welder includes two pairs of opposed grippers defined by pivotally attached upper and lower frames for latching the welder to heat weldable material, such as a length of tubing, upon actuation of a start button by an operator; thereafter, the welder operates unattended. At least a jaw of a pair of jaws disposed intermediate the two pairs of grippers heats the material compressed and lodged therebetween to form a weld in or across the material. A source of gas, such as air, under pressure selectively connected to a bellows provides the power to pivot the upper and lower frames into gripping engagement with the material. A source of electrical signals provides the power to heat the material intermediate the pair of jaws. One or more thermocouples senses the heat of the jaws and generates signals used to control the application of power and to control cooling. After completion of the weld, cooling air is directed to the jaws until the thermocouple(s) signal(s) indicates a sufficiently low temperature.

Abstract: A clip on welder includes two pairs of opposed grippers defined by pivotally attached upper and lower frames for latching the welder to heat weldable material, such as a length of tubing, upon actuation of a start button by an operator; thereafter, the welder operates unattended. At least a jaw of a pair of jaws disposed intermediate the two pairs of grippers heats the material compressed and lodged therebetween to form a weld in or across the material. A source of gas, such as air, under pressure selectively connected to a bellows provides the power to pivot the upper and lower frames into gripping engagement with the material. A source of electrical signals provides the power to heat the material intermediate the pair of jaws. One or more thermocouples senses the heat of the jaws and generates signals used to control the application of power and to control cooling. After completion of the weld, cooling air is directed to the jaws until the thermocouple(s) signal(s) indicates a sufficiently low temperature.

Abstract: A clip on welder includes two pairs of opposed grippers defined by pivotally attached upper and lower frames for latching the welder to heat weldable material, such as a length of tubing, upon actuation of a start button by an operator; thereafter, the welder operates unattended. At least a jaw of a pair of jaws disposed intermediate the two pairs of grippers heats the material compressed and lodged therebetween to form a weld in or across the material. A source of gas, such as air, under pressure selectively connected to a bellows provides the power to pivot the upper and lower frames into gripping engagement with the material. A source of electrical signals provides the power to heat the material intermediate the pair of jaws. One or more thermocouples senses the heat of the jaws and generates signals used to control the application of power and to control cooling. After completion of the weld, cooling air is directed to the jaws until the thermocouple(s) signal(s) indicates a sufficiently low temperature.

Abstract: An RF welder is disclosed that has circuitry that automatically affects system impedance so that, throughout the welding or embossing cycle, a generator is capable of sending energy through die and fabric at a predetermined frequency and cabling is capable of dissipating a load that is less than a preselected amount.

Abstract: A dielectric welding apparatus for welding a plastic sleeve contains a solid state radio frequency generator linked via a matching network to a welding tool. The tool (30) includes a frame (35) with a handle (36), the frame defining a slot in which are opposed welding electrodes (40, 44), the slot being open at one end and at the other end communicating with a wider aperture (39). A pneumatic cylinder (48) can be actuated to urge the electrodes together, both the cylinder (48) and the RF generator (66) being activated by a trigger (50) on the tool (30). The electrodes are coated with an electrically insulating material that is not dielectrically heated, and are readily removable, so they can be replaced, for example when the electrically insulating coating becomes worn.

Abstract: A desk top sealer includes three compartments for housing a solenoid assembly, a power supply and a circuit board, respectively. A source of air flow flows into an initial compartment and is channeled through apertures in brackets forming the two remaining compartments for cooling purposes and is exhausted from each compartment through a base. The circuit board, upon actuation, provides RF energy to a fixed ceramic/metal jaw to heat and weld plastic tubing clamped to the fixed jaw by a movable jaw at ground potential. The movable jaw is guided during translation by a pair of rods extending from a face plate, which rods also prevent rotation of the movable jaw about its axis of translation to maintain the movable jaw in alignment with the fixed jaw. The movable jaw is relatively massive to serve as a heat sink for the heat of the tubing being welded and includes a substantial surface area to dissipate to the ambient environment any heat buildup that may occur.

Abstract: A fixture for use with a radio-frequency welding press includes an independent electrode that is not attached to a platen of the press and which is used to register directly on flexible material workpieces to locate and hold workpieces during a welding operation. The invention also includes shuttles that slidably move welding fixtures to respective positions beneath and laterally away from press platens so that welding and workpiece removal and loading operations can be performed simultaneously on fixtures mounted to respective shuttles. Methods and alternate embodiments are disclosed.

Abstract: Reticles and reticle blanks are disclosed, especially for charged-particle-beam microlithography, that include a peripheral frame and a support frame bonded to each other in a manner that substantially reduces distortion at the bonds as well as membrane distortion. The peripheral frame is bonded peripherally to the support frame in any of various manners including an anodic weld of glass and silicon (the glass containing mobile ions) and a eutectic metal silicon bond wherein the metal can be, e.g., gold, aluminum, germanium, or tin. The glass-silicon and eutectic bonds in which the metal is, e.g., gold, are also resistant to chlorine gas used for routine cleaning of the reticle. In the case of the eutectic metal bond, an intervening layer of chrome or nichrome can be applied between the metal layer and the bonding surface to enhance bonding.

Abstract: In odd-numbered current-supplying periods of a plurality of current-supplying periods constituting a gross current-supplying time, a control unit 42 allows continuous switching actions of only a first set of switching elements at an inverter frequency, with a second set of switching elements remaining OFF. In even-numbered current-supplying periods, the control unit 42 allows continuous switching actions of only the second set of switching elements at the inverter frequency, with the first set of switching elements (24, 28) remaining OFF. As a result of this, a secondary circuit of the power supply apparatus allows a secondary current i2, namely a fusing current I having a substantially trapezoidal current waveform to flow in a positive direction in the odd-numbered current-supplying periods, and to flow in a negative direction in the even-numbered current-supplying periods.

Abstract: A method of preheating a polymer plate by dielectric heating by applying a radio frequency voltage to a laminate in the direction of its lamination through electrodes; a method of producing a laminate, comprising dielectric heating a polymer plate by applying a radio frequency voltage to a laminate in the direction of its lamination through electrodes in a state where the laminate is housed in an annular container encompassing the surfaces of the laminates, and pressing the laminate in the direction of its lamination at least after completion of the application of the radio frequency voltage; and an apparatus for producing the laminate.

Abstract: A bonding apparatus for bonding a thermoplastic pad having a predetermined peripheral shape to a first surface of a carpet using radio frequency energy includes a die electrode and a backing electrode. Both the die electrode and the backing electrode have a peripheral shape that corresponds to the peripheral shape of the pad. In addition, both the die electrode and the backing electrode may have a relief feature thereon that are correspondingly sized and located. Concentrations of electric field intensity in the vicinity of the peripheral edge of the die electrode and along the edges of the relief feature on the die electrode are minimized so that bonding of a pad to a carpet may be effected without thermal runaway. The pad is bonded to the carpet without the occurrence of localized burning of the carpet pile or perforation of the pad.

Abstract: A method of heating an adhesive including the steps of placing a dielectrically heatable adhesive between first and second members. A high frequency electric field is applied between the first and second members sufficient to dielectrically heat the adhesive. The surface temperature of the first member is measured in the vicinity near the adhesive. The electric field is removed after the measured temperature reaches a predefined amount. The invention anticipates measuring the infrared radiation emitted from the surface of the first member and is measured with an infrared detector. A controller receives the measured infrared radiation and compares it to stored values. After the measured temperature reaches a predefined value or values, the controller sends a signal to an RF generator to remove the electric fields.

Abstract: An apparatus for forming coiled tubular assemblies is provided. The apparatus includes a pair of dies formed from a radio frequency (RF) conducting material. The dies each have contoured leading surfaces with these surfaces having grooves with lands between adjacent grooves. The lands of the dies cooperate to form web forming chambers when the pair of dies are moved together in their operative position. In the operative position, the tubes are captured in the aligned grooves with portions of the tubes being squeezed or extruded into the web forming chamber. Application of RF energy to the dies causes the tube portions in the chambers to plasticize and form webs between the coils of the tubes with a predetermined configuration substantially the same as that of the web forming chambers. Both radially coiled and axially coiled tube assemblies are contemplated by the invention. In addition, an easy-to-separate or peel tubular assembly is formed with the above apparatus.

Abstract: A cable assembly (8, 80) including an electrical cable (10) having a flexible tubular jacket (12) and a reinforcing structure (14) attached to the outside of the jacket in a smooth sealing connection (30), and a method of using radio-frequency electrical energy, applied radially through the cable jacket (12) and the reinforcing structure (14), to make the connection (30). A shield conductor (26) inside the cable jacket (14) may be used as an RF electrode, with a second RF electrode (42, 44) circumscribing a portion of the cable (12) and the reinforcing structure (14) and shaping the outer surface of the connection. The RF energy may be used instead to activate an adhesive (108). An outer electrode (118) may be embedded in the reinforcing structure (116) in one variation of the invention.

Abstract: A method of heating an adhesive including the steps of placing a dielectrically heatable adhesive between first and second members. A high frequency electric field is applied between the first and second members sufficient to dielectrically heat the adhesive. The surface temperature of the first member is measured in the vicinity near the adhesive. The electric field is removed after the measured temperature reaches a predefined amount. The invention anticipates measuring the infrared radiation emitted from the surface of the first member and is measured with an infrared detector. A controller receives the measured infrared radiation and compares it to stored values. After the measured temperature reaches a predefined value or values, the controller sends a signal to an RF generator to remove the electric fields.

Abstract: Method of curing inaccessible thermoset adhesive joints, comprising: forming structures to be bonded at mating surfaces when assembled, the shortest distance from the mating surfaces to the exterior of the assembly inhibiting the application of radio frequency heating by exterior electrodes; while forming the structures, molding into a least one of the structures, spaced from the surfaces to be adhered, a fiber or film-like electrode of sufficient thickness and spacing to project radio frequency waves through such one structure to the adhesive when energized; assembling the surfaces together with a thermoset adhesive therebetween in intimate contact of each of the surfaces; and connecting the fibrous or thin filmed electrode in a circuit for passing radio frequency waves across the adhesive to effect dielectric heating of the adhesive for a controlled period of time and at a predetermined temperature rise for curing.

Abstract: An H-field electromagnetic heating system for fusion bonding, particularly useful in the sealing of telecommunications cables and closures, comprises a composite bonding material having a bonding matrix and susceptors, the susceptors being magnetically reactive at a frequency above 50 MHz, and an applicator for applying radiant electromagnetic energy to the composite bonding material, at a frequency above 50 MHz (preferably 75-500 MHz). The applicator may take the form of a quarter-wave resonator having an inner conductor and an outer conductor which at least partially surrounds the inner conductor, the two conductors being shorted at a common end. The material to be heated is placed between the conductors. The inner conductor may include a resonator tube which is capacitively coupled to the power supply by a capacitive probe connected to the center conductor of a coaxial connector.

Abstract: Process for automatic connection, at the moment of pressing, between a source (26) of electric current and the metal parts (35), connected in series, of the piles (30) of packages (31) for making plastic laminates to permit electric endothermic heating, there being placed in the pressing machines (10), at those parts which will come in contact with the ends (36,37) of the pile (30), metal contact sheets (20,21) connected to the source (26) of electric current.

Abstract: Slot interlock connectors for RF welding electrodes include an electrode having a working edge, at least two ends and an integral mounting block which has ends which overshadow the ends of the electrode and provide substantially flat alignment surfaces adjacent to the ends of the electrode. The electrode may have a curved or straight working edge and the integral mounting block may be disposed on the interior concave surface of the electrode or the exterior convex surface of the electrode. According to the invention, the electrode can have one, two, three, four, or more working edges with one, two, three, four, or more integral mounting blocks. The ends of the mounting blocks overshadow the ends of the electrodes and provide substantially flat alignment surfaces or alignment channels adjacent to the ends of the electrode. Several embodiments of connectors are disclosed, including connectors having L, T, +, and * configurations.

Abstract: A method of synthesizing encapsulated nanocrystals inside protective shells is disclosed. This method produces nanocrystals of metals, alloys, and compounds which are individually encapsulated by protective graphite shells which completely separate the nanocrystals from the environment. A separation method is also disclosed which eliminates most of all other debris except the encapsulated nanocrystals from the preparation product.

Abstract: Films of thermoplastic material may be sealed together by application of a radio frequency field through a pair of oppositely positioned electrodes. Preferred thermoplastic materials have a low dielectric dissipation factor, and such materials include polyethylene. The sealing apparatus includes a circuit having compensation and matching circuits for providing resonant operation and minimizing the amount of reflected energy from the electrodes. Through the use of this invention effective RF sealing is produced-between films of thermoplastic material having a low dielectric dissipation factor. Further the sealing apparatus preferably includes at least one electrode coated with a ceramic and a release material for providing thermal conduction to the films, thereby enhancing the sealing effectiveness of the apparatus.

Abstract: The present invention relates to a joining method, a joining apparatus and a joining agent capable of joining two bodies to be jointed in a large size or in a complicated shape in a good joining condition. Specially, the present invention is to provide an improvement in a control of the current supplying method applicable for the electrically heating of the ceramic bodies or a joining agent in an electric conduction (a elecrode switching type due to a plurality of fixed electrodes and a switching control type between two kinds of the electric power sources), a control method of a auxiliary heating, a control of the holding apparatus (the control by the free thermal expansion at the pre-heating, a adaption of a balance mechanism and a measurement of the displacement), the adjustment of the shape at the butted portion (improvement of the pipe joint structure) and a joining agent superior in the joining strength.

Abstract: A process for obtaining long, continuous, thermoplastic welds on large structures. A series of tabs are used in pairs and especially in alternating, overlapping pairs to obtain resistance heating of a strip material placed in the bond line. The resistance of the tabs is less than that of the strip material. Conducting braid-tubes afford continuous welding when the bond line is curved. Alternatively, an electromagnetic field is used to take advantage of the induction heating. A wide susceptor is used to weld a current conducting substrate while avoiding bulk heating of the substrate. The unexpected property of current-conducting braid-tube susceptors, in which induction heating takes place at the center rather than at the edges of a flattened braid-tube susceptor, is used to obtain long continuous curved welds.

Abstract: A mold, having a mold cavity commensurate with the shaping, forming or welding to be made, includes an RF energized heater in close proximity to the mold cavity for heating plastic tubing placed within the mold cavity to a temperature sufficient to shape, form or weld the plastic tubing. An RF generator, electrically connected to the RF energized heater, monitors the power applied as a function of the temperature of the heater to heat the plastic tubing to a precise temperature. The mold is of thin wall construction with minimal thermal inertia to expedite both heating and cooling. Various configurations of the mold may be made to form tip shaping, forming or welding, butt welds, annular welds and the like to weld single thermoformable elements or join multiple thermoformable elements.

Abstract: A method for the heating and joining together, preferably for welding, of workpieces by use of a generator. Where, during a heating interval the generator supplies high-frequency energy to at least two electrodes disposed on the workpiece and where the energy supply is controlled by a predetermined time-related curve, with respect to a target value. Accordingly, the energy supply is controlled with reference to the target value by monitoring a first parameter, e.g., high-frequency voltage, high-frequency current or generator anode current. Also, during the heating interval at least one further parameter is monitored, and in the event of an inadmissible divergence in the control system of the first parameter, a subsequent control of the energy supply is carried out.