Abstract: A solder ball attachment system for manufacturing an integrated circuit or the like is disclosed. The solder ball attachment system includes a flux station adapted to apply flux onto a substrate and a solder ball placement station adapted to place solder balls onto the flux. A conveyor assembly is included to move the substrate between the flux station and the solder ball placement station.

Abstract: A transfer fluxing apparatus is provided. The apparatus is a flux reservoir for holding flux, a compliant pad attached to an opening in the flux reservoir and a means for controlling deposition of flux onto the compliant pad. The apparatus can be attached to an automated component placement machine. In the preferred embodiment of the invention, the control means is a valve located within the flux reservoir. The valve is opened by applying pressure to a plunger that extends through the compliant pad. When the plunger is pressed, the valve opens, and flux falls onto the compliant pad. Flux then passes through the pad to a component placement site. A method for automated fluxing and to component placement also is provided.

Abstract: There are provided a chamber having openings which are opened to an outer air and through which a solder-adhered object w is passed and having a heating/melting area and carrying areas arranged adjacent to the heating/melting area, a carrying mechanism for carrying the solder-adhered object w into the heating/melting area, a formic-acid supplying means for supplying a formic acid into the heating/melting area, an exhausting means for exhausting a gas from the heating/melting area and its neighboring area to lower a pressure in the heating/melting area rather than an outer air, heating means for heating directly or indirectly the solder-adhered object w in the heating/melting area, and air-stream suppressing means for disturbing a gas flow between the heating/melting area and the carrying areas.

Abstract: There is disclosed a novel method for attaching electronic components to an electric circuit printed on a glass substrate. The method comprises depositing a desired quantity of an uncured, ultraviolet radiation-curable, anisotropic conductive adhesive in a desired location on a metallized glass substrate having an electric circuit formed on a surface thereof. An electronic component having electrical contacts formed on a portion thereof is applied to the uncured, deposited adhesive so that the bumps are positioned in the adhesive and in register with desired portions of the electric circuit on the substrate. An amount of pressure sufficient to render the adhesive selectively conductive at locations between the electric circuit and the electrical contact on the electronic component and substantially nonconductive at other locations is applied to the electronic component, such that the electrical contacts make an electrical connection with desired portions of the electric circuit.

Abstract: Method of welding metal wherein a crack to be welded is surrounded with a flux in a substantially water-free environment and welded. The flux acts as backing for the welding operation and permits the welding to be carried out in the absence of an inert gas purge or metallic backing pre-placed on the weld.

Abstract: This disclosure describes a technique for fusing self-fluxing metallic coatings on non-cylindrical objects without the need to conduct the fuse operation in a vacuum furnace or some other type of protective environment. The technique consists of first applying the self-fluxing coating to the surface, then optionally applying a ceramic coating on top of the self-fluxing coating. The object is then submerged into a vessel containing a low-melting inert material. The aggregate is then heated, and as the glass becomes molten, it encases the object and protects it from oxidation. As heating continues, the fusing temperature is reached and the self-fluxing alloy becomes molten. The ceramic coating encases the self-fluxing alloy and acts as a mold. When fusing is complete, the aggregate is then slowly cooled to ambient temperature. The glass frit and the ceramic shell are then removed, and one is left with an object coated with a uniform thickness of a dense adherent fused coating on the surface of the object.

Abstract: There is provided a method for applying solder to an element on a surface of a substrate. The method comprises the steps of (a) placing a mold over the surface, where the mold includes a conduit that contains the solder, and (b) heating the solder to a molten state so that the solder flows from the conduit onto the element. The conduit enjoys two degrees of horizontal freedom with respect to the surface such that the conduit becomes substantially aligned with the element when the solder is in the molten state. There is also provided a system for applying solder to an element on a surface of a substrate.

Abstract: There is disclosed a surface reformation method of a high polymer material such that by irradiating and excimer-laser beam to only a predetermined area in which electronic parts and the like are temporarily immobilized by a liquid on a substrate which has a high polymer layer on the surface, wettability of the liquid for temporary immobilization only with respect to the predetermined area is improved. After the electronic parts are temporarily immobilized on the substrate by using the method, the electronic parts can be soldered with preferable durability by a fluxess reflow soldering.

Abstract: A wire processing apparatus includes an applicator (60) for crimping a crimp contact onto an end of a wire (2) and solder depositing units (7, 8) for depositing solder onto an exposed core on the wire end, all of which serve as wire processing units. The applicator (60) and the solder depositing units (7, 8) are attachable to and removable from a placement section (13a) and are interchangeable with each other. Each of the solder depositing units (7, 8) includes a flux bath (15) for storing a flux liquid therein, a solder bath (16) for storing solder in a molten state therein, and a flux liquid holding tube having a holding hole for holding the flux liquid therein and capable of releasably receiving the core. The core is moved downwardly into a solder portion raised by the surface tension of the solder stored in the solder bath 16, whereby the solder is deposited on the core.

Abstract: A flux composition for brazing aluminum, comprising a fluoride flux, at least one selected from a butyl rubber and a petroleum resin, and a solvent. The novel flux composition has excellent processing properties and provides brazed areas (fillets) with good appearance.

Abstract: Components composed of aluminum or an aluminum alloy with a coating comprising an aluminum-silicon alloy deposited thereon by applying an alkali metal fluorosilicate and heating the resulting treated material. The alloy layer is effectively protected against re-oxidation by a non-corrosive, alkali metal fluoroaluminate layer (e.g. a potassium fluoroaluminate layer) which forms simultaneously.

Abstract: A soldering flux suitable for soldering of small electronic components comprises 0.1-50 mass percent of an organic acid, 5-40 mass percent of a solvent, and 10-95 mass percent of a thermosetting resin (including a curing agent), which is preferably a bisphenol A epoxy resin and an acid anhydride or amine curing agent. This flux can be used to prepare a solder paste by mixing with solder powder. This soldering flux can secure an electronic component simultaneously by soldering and by the resin, simply by a soldering operation at a soldering temperature of at least 150° C., and cleaning after soldering is no longer necessary.

Abstract: There is provided a method for forming end-face electrodes in which the end-face electrode can be securely formed with solder at a position in which a side electrode is formed and it can be formed without being affected by a jig for fixing a solder solid. By forming linear gaps on a master substrate, module substrates and a waste substrate are formed. At the side end of the gap of the module substrate, a side electrode is formed. A solder solid is pressed into the part of the gap in which the side electrode is formed and a reflow jig is placed. The surface of the solder solid is coated with flux and the solder solid is melted by heating so as to form the end-face electrode protruding from the substrate surface in the side electrode.

Abstract: The invention is a single phase flux composition suitable for use with high density arrays, that comprises dicarboxylic acid in an amount sufficient to react with the oxidized surface area in a high-density array, a first organic solvent, and a second organic solvent having a higher evaporation temperature than that of said first organic solvent. Preferred dicarboxylic acids are adipic, pimelic, suberic, azelaic and sebacic acids. Preferably, the composition comprises greater than 6% dicarboxylic acid, more preferably greater that 6% to about 15%, and even more preferably from about 8% to about 10% of the dicarboxylic acid. Preferred amounts of the first organic solvent are in the range of from about 25% to about 75% by weight and preferred amounts of the second organic solvent are from about 10% to about 35% by weight. Preferably, the ratio of the first organic solvent to the second organic solvent is about 3:1.

Abstract: The invention relates to an aluminium extrusion alloy comprising in weight percent: Mn 1.0-1.4, Cu 0.2-2.0, Mg 0.1-0.6, Si 0.15-1.0, Fe 0.8 max., Zn 0.25 max., Ti 0.15 max., Cr 0.35 max., Zr and/or V in total 0.25 max., others up to 0.05 each, total 0.15, balance aluminium, and with the proviso that (Cu+Mg)>0.7, and which aluminium extrusion alloy is particularly suitable for application in brazed assemblies, and the invention further relates to a method of its manufacture.

Abstract: Solder spheres which can avoid blackening during transportation have a substantially uniform coating of a lubricant on the surfaces thereof. They are produced by dipping freshly prepared solder spheres in a lubricant solution with a concentration of from 10 ppm to 1000 ppm followed by collection of the spheres and drying. The lubricant is preferably selected from an aliphatic hydrocarbon lubricant, a higher fatty alcohol or acid lubricant, a fatty acid amide lubricant, a metal soap lubricant, a fatty acid ester lubricant, a fluoroplastic lubricant, a silicone lubricant, and a combination thereof.

Abstract: A process for manufacturing a vacuum insulated stainless steel coffee server, which includes the steps of welding an outer shell (32) to an inner liner (34) then placing a ceramic ring (38) in a vacuum base (40) and slipping the vacuum base on the shell with the spacer forming a welding gap therebetween. The next step is welding the vacuum base to the shell at the welding gap formed by the ring and applying brazing powder and flux around a hole (36) in the liner, followed by inserting a threaded coupling (48) through the hole and a mating bore (42) in the base, with a first nut (52) on the coupling acting as a shoulder. The next step is applying brazing powder and flux around the nut and the bore in the vacuum base and then positioning the coffee server in a vacuum furnace and evacuating, while simultaneously elevating the temperature joining the coupling to the contiguous structure.

Abstract: There is disclosed a surface reformation method of a high polymer material such that by irradiating and excimer-laser beam to only a predetermined area in which electronic parts and the like are temporarily immobilized by a liquid on a substrate which has a high polymer layer on the surface, wettability of the liquid for temporary immobilization only with respect to the predetermined area is improved. After the electronic parts are temporarily immobilized on the substrate by using the method, the electronic parts can be soldered with preferable durability by a fluxess reflow soldering.

Abstract: A flux transfer apparatus has a frame having an aperture portion in its lower central portion, and a mesh is stretched across the frame with a high tension and with a mesh pitch at least smaller than the diameter of projections to be formed therein is used. Projections made of resin are provided in the mesh portion provided at the aperture portion of the frame.

Abstract: An automated soldering apparatus includes a conveyor for transporting a printed circuit board along a predetermined path, a fluxer located below the conveyor for coating the circuit board and the electronic components with flux, and a preheater located downstream of the fluxer for heating the circuit board and the electronic components to a predetermined temperature. A molten solder bath is provided downstream of the preheater for applying a molten solder to selected areas of the circuit board. A cooling assembly is arranged downstream of and adjacent to the molten solder bath. The cooling assembly is operable to cool the applied molten solder at a rate of approximately as high as 1.0° C. per second until the molten solder reaches its solidus temperature.

Abstract: Fluoride-based flux is uniformly dispersed in and mixed with synthetic resin, which has fluidity at room temperature and sublimes at a temperature lower than a brazing temperature, so as to constitute 40 to 70 wt. % of the mixture, thereby producing coating material. This coating material is applied to coating belts which undergo rotation and is transferred from the coating belts to the surface of the aluminum material. The coating material has high viscosity and stably adheres to the transferred areas.

Abstract: Fluoride-based flux is uniformly dispersed in and mixed with synthetic resin, which has fluidity at room temperature and sublimes at a temperature lower than a brazing temperature, so as to constitute 40 to 70 wt. % of the mixture, thereby producing coating material. This coating material is applied to coating belts which undergo rotation and is transferred from the coating belts to the surface of the aluminum material. The coating material has high viscosity and stably adheres to the transferred areas.

Abstract: A soldering flux includes a non-acidic resin in an aqueous composition. The flux can also include an activating agent and a surface-active agent that promotes surface wetting.

Abstract: The invention provides metal connecting composition for connecting metal to metal with removing oxide film on the mother metal surface. The metal connecting composition contains metal particles and hydrocarbon compound having C—H bonding dissociation energy of a value equal to or lower than 950 KJ/mol. When metal pieces between which the metal connecting composition is applied is heated, the hydrocarbon compound is dehydrogenated to form radical, and the radical reduces oxide film on the metal surface to be connected.

Abstract: A ball arrangement method and arrangement apparatus for simultaneously mounting balls on a mounting object by the steps of holding the balls by suction on ball suction holes in a ball arrangement device having the ball suction holes arranged, transcribing flux or a solder paste onto the balls held by suction, and transferring the balls onto the mounting object. In the method and apparatus, a flux supplying unit composed of a head plate 5 at an end thereof is provided, flux supplying nozzles 7 are arranged over the head plate 5 at positions corresponding to the ball suction holes 6 in the ball arrangement device 1.

Abstract: Solder balls are mounted on electrodes with an active resin therebetween. The solder is heated and melts to be connected to pads of an LSI chip, thereby forming solder bumps on the chip. In a method of forming bumps, a method of mounting flip chips, and a mounting structure, by the use of the active resin, a flux washing process can be eliminated and at the same time, an assembly cost can be minimized.

Abstract: The method for coating the seam of a welded tube of this invention includes applying a mixture of the desired protective metal coating in powdered form and a liquid flux over the internal surface of the welded seam with the welded seam located in a lower portion of the tube, then heating the welded seam to the melting temperature of the protective metal coating, melting the metal coating which flows over the seam forming an adherent metallurgical bond. The preferred apparatus includes a wand which extends between the opposed edges of the open seam tube in the welding apparatus and extends axially through the tube to overlie the welded seam spaced from the welding apparatus. The wand includes three conduits transmitting the powdered protective metal coating, liquid flux and nonoxidizing gas to the applicator which includes a nozzle which atomizes and sprays the liquid flux over the internal surface of the seam and which combines with the powdered protective metal coating to form a paste.

Abstract: The present invention relates to a method for making an array of metal balls. The method includes the step of generating a first pattern on a metal foil which includes a plurality of foil projections. The method also includes the step of generating a second pattern on a carrier substrate. The second pattern includes a plurality of carrier recesses that are arranged and configured to correspond with the foil projections of the first pattern. The method further includes the steps of placing the metal foil and the carrier substrate together such that the foil projections of the metal foil fit within the carrier recesses of the carrier substrate, and melting the metal foil such that the foil projections form metal balls positioned within the carrier recesses of the carrier substrate. The invention also relates to metal ball arrays constructed via the above method.

Abstract: A soldering flux suitable for soldering of small electronic components comprises 0.1-50 mass percent of an organic acid, 5-40 mass percent of a solvent, and 10-95 mass percent of a thermosetting resin (including a curing agent), which is preferably a bisphenol A epoxy resin and an acid anhydride or amine curing agent. This flux can be used to prepare a solder paste by mixing with solder powder. This soldering flux can secure an electronic component simultaneously by soldering and by the resin, simply by a soldering operation at a soldering temperature of at least 150° C., and cleaning after soldering is no longer necessary.

Abstract: An apparatus is provided for the drying of electronic components. The invention provides multiple holes through which air is passed before striking the components. This provides the apparatus of the invention with multiple air knives, thereby breaking major air flow into multiple eddy currents whereby these eddy currents have a low enough air pressure gradient such that the electronic components are not damaged or lifted from the conveyer belt on which they are transported.

Abstract: A soldering machine using lead-free solders is provided which can uniformly heat a printed circuit board and electronic parts to be mounted thereon, and which can solder the electronic parts without thermally damaging them. A porous member having a number of holes formed therein is disposed between a blower fan and a heater for making uniform the pressure of a fluid. A radiation plate is disposed between the heater and a heating target for blowing the fluid having been heated by the heater to the heating target in the form of a turbulent flow. The heated fluid is blown to the heating target for heating the same, whereby solder is melted.

Abstract: A first embodiment includes a control system which operates a spray gun to apply an even coating of flux to a circuit board or a plurality of different length circuit boards irrespective of the speed that the circuit board(s) move through a coating chamber. In a second embodiment, the control system pulses the spray gun on and off with a pulsing pattern that coats a plurality of zones of a circuit board with spray patterns of different length and thickness.

Abstract: A flux which contains irreversibly dehydrated K2AlF5, for soldering light metal materials, in particular aluminum. The flux has the advantages of forming a very uniform flux coating on the workpiece or workpieces to be soldered and exhibiting outstanding flow of the solder. An appropriate soldering process, an aqueous flux suspension and preparation processes for the flux are also disclosed.

Abstract: The present invention is a water-based binder used when manufacturing aluminum brazed products such as engine radiators, condensers for car air conditioners, and the like. The water-based binder is obtained by saponifying an ester methacrylate polymer that has an acid value and a glass transition temperature within specified ranges. In the presence of an alcohol that is water soluble and volatile and has a flash point higher than a specified temperature, the brazing composition, in which this binder and flux and the like are mixed, does not have the risk of catching on fire or exploding and also has excellent wettability and can be uniformly coated onto an aluminum material.

Abstract: A method by which a conventional circuit trace (14) is modified with a layer (16) of high-conductivity solder alloy to yield a high-current circuit trace (12) for high-current routing on a substrate (10). The method generally entails the use of a solder composition that contains a dispersion of metal particles (18) in a solder alloy (20). The metal particles (18) are selected on the basis of having a higher electrical conductivity than the solder alloy (20), and are present in sufficient amounts so that the electrical conductivity of the solder composition is significantly higher than that of the solder alloy (20). The solder composition is deposited on a conductor (14), and then reflowed to form a conductive layer (16) on the conductor (14). The metal particles (18) remain as a discrete dispersion within the conductive layer (16) in order to suitably promote the conductivity of the layer (16).

Abstract: The top peaks of the outer fin are coated with slime-like flux. A sandwich unit is assembled from the outer fin and the tube plates by attaching the tube plates to the respective sides of the outer fin such that the surfaces of the tube plates having the butt bead faces formed thereon face inward. The butt bead faces on the respective tube plates on either side of the sandwich unit are coated with the slime-like flux. A plurality of sandwich units whose tube plates are coated with the flux are laminated and brazed, and the thus-formed assembly is heated in a heating furnace, to thereby braze together the tube plate pairs and the tube plates connected to the outer fin.

Abstract: To present a method and apparatus for forming favorable solder bumps on a substrate of electronic component or the like, in which metal paste is applied on the lower surface of solder balls attracted by a suction tool, and the solder balls are positioned to contact with recesses having the electrode in the bottom, so that the metal paste adhered to the solder balls is adhered to the top of the recesses. Next, the solder balls are moved reciprocally in the vertical direction or horizontal direction. As a result, the metal paste adhered to the top of the recesses is collected to fill up the recesses. Then, the solder balls are put on the top of the recesses, and heated and fused, and solder bumps are formed.

Abstract: Brazing or soldering materials which effectively improve the wettability of the brazing alloy or solder without using flux and a method of manufacturing such materials are provided. A metallic base is placed on turntable inside a vacuum chamber. A copper target is affixed to a sputtering electrode above the metallic base. Air is removed from the vacuum chamber through a vacuum outlet to increase the vacuum therein to a specific pressure, and carbon tetrafluoride and argon are introduced from a gas inlet to control the sputter pressure. Thereafter, turntable is rotated while a high frequency voltage is applied between the target and the metallic base to form a halide layer, such as a layer of copper fluoride, on a surface of metallic base.

Abstract: According to the present invention, an insert material is laid between metal beryllium and copper alloy, wherein the insert material has the minimum, solidus temperature of not lower than 870° C. to the metal beryllium and copper alloy, respectively, and a single diffusion bonding process is performed under the condition that the temperature is not lower than 850° C. and less than the minimum solidus temperature, and the pressure is 20 to 30O MPa, so that the metal beryllium, copper alloy and stainless steel can be effectively bonded without deterioration of corrosion resistance for sensitizing of the stainless steel.

Abstract: A soldering flux containing borneol, which is also referred to as bornyl alcohol. A method soldering using such a flux is also disclosed. Even minor proportions of borneol in the flux help reduce ionic residue from the flux after soldering. Larger proportions of borneol can give the flux tackiness for wave soldering operations. The flux preferably comprises borneol and an organic acid activator that volatilizes during soldering. The flux is applied as a solution of borneol and the organic acid activator in a solvent that substantially evaporates before soldering without leaving any measurable solvent residue.

Abstract: Disclosed is a method of preventing a gold plate connector of a printed circuit board (PCB) from being contaminated during a soldering process. The disclosed method prevents the gold plate connector coupled with the printed circuit board from being contaminated during wave soldering of the printed circuit board after spreading flux over the printed circuit board on which electronic components are mounted, and the method includes the steps of: forming a strip mask in a form of a membrane by solidifying a masking solution after spreading the masking solution capable of being solidified over the gold plate connector of the printed circuit board, performing the spreading of the masking solution before the spreading of the flux; and removing the strip mask from the gold plate connector after performing the wave soldering. As a result, it is not necessary to perform a washing operation of the gold plate connector. The washing operation can be troublesome, time-consuming, and inconvenient.

Abstract: The seamless, ring-shaped brazing material comprises a brazing metal and a flux uniformly dispersed in the brazing metal for brazing nonferrous metal members and has a relative density of 0.90 or more. The seamless, ring-shaped brazing material is produced by (a) mixing brazing metal powder and flux powder uniformly; (b) pressing the resultant mixture to a powder compact billet; (c) forming the billet into a pipe by hot extrusion; and (d) slicing the pipe into rings.

Abstract: Provided are a soldering flux or paste containing an organic substance which has at least two hydroxyl (--OH) groups in a molecule and of which the temperature at which the mass % becomes approximately 0% is not lower than approximately 170.degree. C. and not lower than the solid phase linear temperature of the solder, as measured by thermal gravimetry in which a flow rate of an air or nitrogen (N.sub.2) gas atmosphere is 200 ml/min and a rate of temperature rise is 10.degree. C./min, and a soldering method using the same. The soldering flux or paste of the present invention gives good wettability to a matrix to be bonded in a normal temperature profile and in a non-reductive atmosphere without leaving any residue.

Abstract: A method is disclosed of making a braze sheet for a brazed assembly. The method includes the steps of providing a sheet of a core material and a composition cladding and mechanically embedding a flux into the sheet.

Abstract: A method of avoiding generation of waste water while brazing components made of aluminium or an aluminium alloy using a flux, especially a flux composed of an aqueous suspension of potassium fluoroaluminate. Since used suspension is replaced with fresh suspension after a given period of time and the apparatus regularly have to be cleaned, waste water is produced which contains flux, e.g. potassium fluoroaluminate. In the past, such waste water has been discharged into the environment. It has now been discovered that such waste water can be recycled to the brazing process after separation of the flux. In this manner, the production of waste water can be largely avoided. Since surfactants are frequently used, and these are likewise recirculated, a corresponding saving in terms of surfactant is possible. Furthermore, the environment is protected correspondingly.

Abstract: An automated method of applying flux to substrate on which a semiconductor chip is to be assembled in a flip chip configuration by applying a controlled amount of flux to the substrate by a brush that applies the flux to the substrate in a programmed pattern of strokes thereby overcoming the surface tension of the flux/substrate surface. The programmed pattern of brush strokes is determined empirically for the specific combination of substrate and chip that is being assembled and is thus repeatable and operator independent. The empirically determined program also determines the amount of flux that will be applied to the substrate for the specific combination of substrate and chip being assembled. The empirically determined program is applied to a mechanical stage that moves the brush and to a flux reservoir by a CPU.

Abstract: The invention relates to a method for drying fluxing of a metallic surface before soldering or tinning using an alloy, according to which the surface to be fluxed is treated, at a pressure close to atmospheric pressure, with a gaseous treatment atmosphere comprising excited or unstable species and being substantially free of electrically charged species, which is obtained from a primary gas mixture and, optionally, an adjacent gas mixture, the primary gas mixture being obtained at the gas outlet of at least one apparatus for forming excited or unstable gas species, in which an initial gas mixture comprising an inert gas and/or a reducing gas and/or an oxidizing gas has been converted, the adjacent gas mixture not having passed through the apparatus.

Abstract: A heat exchanger assembly includes at least one tube having an internal surface and an external surface, a composition cladding having at least lithium and magnesium applied to either one of the internal surface and external surface of the tube, and at least one component disposed adjacent the composition cladding, whereby the tube and component are joined together during a controlled atmosphere brazing process.

Abstract: A method for repairing and joining aluminum alloy articles and structures, such as heat exchangers for use in automotive applications. The method utilizes a flux-coated soldering rod (10) that is used to deliver a solder alloy (12) and a flux compound to a region to be repaired. The flux compound has a higher melting temperature than the solder alloy (12), and is present as a coating (14) that sufficiently thermally insulates the alloy (12) to cause the flux compound and the solder alloy (12) to melt nearly simultaneously during the soldering operation. The solder alloy (12) is preferably a zinc-aluminum alloy, while the flux coating (14) preferably contains a cesium-aluminum flux compound such as potassium cesium tetrafluoroaluminate, dispersed in an adhesive binder that will readily volatilize or cleanly burn off during the soldering operation.

Abstract: A method for applying a plurality of solder globules to a substrate has a solder-globule fixing method, a plurality of glass fibers and a fibre holder. The solder-globule fixing method has provided therein a plurality of passages whose cross-sectional areas are smaller than the cross-sectional areas ofthe solder globules to be applied. The fibre holder is arranged relative to the solder-globule fixing device in such a way that between the fibre holder and the solder-globule fixing device a cavity is formed, which is adapted to be acted upon when submitted to pressure via a pressure-transmitting conduit. The fibre holder holds the glass fibres in alignment with the passages.