Abstract: A packaging machine has a roll supporting device with a support shaft rotatably supporting a film roll which extends in an axial direction, an elongated bag-forming film being wrapped around the film roll, a bag forming device which pulls out the film from the film roll and forms the film into a shape of a bag, a packaging device for filling the bag-shaped film with articles to be packaged and sealing the film to produce a package, a roll displacing mechanism for displacing the roll supporting device in the axial direction, and a roll position controller for controlling the roll displacing mechanism to adjust the position of the roll supporting device. The bag forming device includes a former for bending the film into a tubular form and a former roller for guiding the film to the former.

Abstract: A form-fill-seal packaging machine has not only the basic elements such as devices for transporting a film and longitudinally and transversely sealing it but also a former and a chute formed integrally together as a former unit which is made detachably attachable to the frame structure of the packaging machine by an attachment mechanism. The former unit has wedge-shaped members, and the attachment mechanism includes a mobile member constrained to move linearly and a lever which is attached to the frame structure such that a one-touch operation to rotate this lever causes this mobile member to move towards or away from the wedge-shaped members on the former unit and to engage with them or disengage from them.

Abstract: A method is provided for hermetic packaging of unimpregnated and impregnated adsorbents which provides for improved packing densities, reduced attrition losses, and reduced exposure of the adsorbent to environmental or other contamination. Furthermore, the method inherently provides for identification of instances of packaging failure. The method entails hermetically sealing a collapsible gas and vapor impermeable vessel containing an adsorbent which is at an elevated temperature. Subsequent cooling of the adsorbent results in the production of a partial vacuum within the vessel. As a result of this partial vacuum, the environmental atmospheric pressure collapses the vessel to firmly compresses the adsorbent in a hermetically sealed low-pressure environment to provide the stated advantages.

Abstract: A method of making reclosable packages is provided. A package is formed from thermoplastic film. The package includes a reclosable zipper. The sides of the package are slit and spread apart. A slider is inserted on to the zipper through a side slit.

Abstract: The apparatus and method attaches a section of unsupported interlocking zipper transversely to portion of film drawn around a fill tube of a form fill and sea machine. This includes the steps of driving and guiding said zipper horizontally around the outside of the film formed around the tube in a direction transverse to direction of movement of the film, after the formation of the fin seal. An alternative embodiment drives and guides the zipper horizontally around the inside of the film formed around the tube prior to the formation of the fin seal. A retractable ledge may be used to guide the zipper in the alternative embodiment. A slider operated zipper can also be used in this alternative.

Abstract: A process is disclosed for collecting and disposing of waste (1), in particular household rubbish. Waste is separately collected and sorted at the place at which it is produced in plastic bags (3a, 3b, 3c) provided with appropriate distinguishing markings (2a, 2b, 2c) in accordance with recycling criteria. Portions of waste (4) are packaged by closing and vacuum-sealing the plastic bags, and the closed and vacuum-sealed bags that contain the various types of waste are placed together at random into at least one common garbage container (5) and transported to a central collecting point where the plastic bags are sorted according to their markings for final disposal and/or recycling.

Abstract: An article metering device, and a method of metering articles, is disclosed. The article metering device is positioned along a path of travel at a downstream end of a feed conveyor, and at an upstream end of a take-away conveyor of an article handling and packaging system. The article metering device is constructed and arranged to accumulate a first queue of articles on the feed conveyor, to accumulate a second queue of articles on the take-away conveyor, to space the respective articles within the second queue of articles from one another, and to then selectively advance selected ones of the articles within the second queue of articles along the path of travel for being carried on the take-away conveyor toward an infeed conveyor of a downstream packaging machine.

Abstract: A method and apparatus for a vertical form, fill and seal machine to produce a constant pull length of the film and therefore packages of consistent length, whatever the velocity of the machine. When the film is pulled, and the pulling ceases, there is always a finite overrun of pulled film. The method according to the invention determines the velocity for operation of the machine while accounting for the overrun in order to produce packages of constant length. The apparatus includes a motion controller for calculating the velocity and operating the machine at the calculated velocity during the time that the film is being advanced in the vertical form, fill and seal machine.

Abstract: The present invention relates to a method of forming and closing bags, said method comprising steps consisting in delivering closure means comprising at least two complementary strips disposed on respective backing sheets, in delivering a film that is to constitute the walls of the bag, in heat-sealing a first backing sheet of the closure means to the film along at least one of the longitudinal edges of said sheet, with the closure means being angularly positioned transversely to the longitudinal direction of the film, in shaping the resulting film as equipped with the closure means into a tube, and in heat-sealing the second backing sheet of the closure means to an opposite face of the film along only one edge of said second sheet.

Abstract: A protective foam cushion-making apparatus dispenses reactive foam components into an interior space between two panels of plastic film to form protective foam cushions. The apparatus includes a supply of plastic film and a film a driving assembly, such as two pliable rollers. A foam component dispensing assembly is interposed between the film panels and injects reactive foam components into the interior space where they are mixed together to form a mass of expandable foam. The plastic film forms a flexible mixing chamber in the area between the two pliable rollers in which the reactive foam components are mixed together after they are dispensed from the foam dispensing assembly.

Abstract: A cushioned shipping assembly includes a carton and foam inserts to support a product shipped by a supplier, which elements are successively returned by an end user to be reused in the same or other shipping assembly, while various components are recycled as they become spent. In some embodiments, the carton collapses to a diminished size for return. A resource center reroutes or refurbishes the components, recycling aged or spend pieces. On-premises pelletizing of reclaimed polymer provides a more efficient, environmentally clean system. Spent inserts of identified polymer may be diverted to users of specific resins.

Abstract: A deep groove ground-contacting roller for a reel type mower assembly having a plurality of interfitting intermediate roller segments and matching end segments mounted on a transverse bearing mounted axle rod in tight abutment. Stop rings engage the end segments and the axle rod to fix the roller segments on the rod to form a roller body. Each roller segment includes a cylindrical hub and a disc element extending radially therefrom with converging planar annular side surfaces intersecting to form a rounded ground-contacting ridge. The disc elements and the hub sections combine to form a deep groove with angled side surfaces and a right circular cylindrical bottom.

Abstract: A gang mower mountable on a tractor and having a plurality of independently-cutting mower units whose cutting heads are individually powered by hydraulic motors. Each mower unit is suspended from the end of a support arm which can move vertically through a distance of about 12 inches, each mower unit is itself mounted beneath a swivel ball joint that allows the mower to undergo pitch, roll and yaw motions as well as the up and down movements of the support arm. Moreover, this mower suspension mechanism allows each of the mower units to hold the ground due to its own weight alone and does not require any stabilizing force to be applied through springs or otherwise. The freedom of motion of the suspension mechanism in combination with an independent drive for each mower unit yields a gang mower with a smooth, wide-cut mowing action.

Abstract: A reel-type lawn mower and tractor assembly which includes a pivotally-mounted lift arm on the tractor. A lawn mower is pivotally attached to the laterally extending end of the lift arm and is caster-connected relative to the lift arm by a device of an intervening link which is angulated to be at one elevation at the top of the mower and at a lower elevation to the rear of the mower where the connection is made with the tractor lift arm.

Abstract: A power-driven lawnmower having a main chassis supporting an operator, a pair of forward drive wheels, and a steering wheel utilizes a floating mower deck which covers or houses at least one driven mower blade. The deck is connected to the main chassis by a pair of arms terminating in ball joints affixed to the mower deck which is supported on ground engaging wheels such that the mower deck follows the contour of the ground. A flexible drive belt is connected to a constant power take off element on the main chassis and to the drive mechanism on the deck such that belt is entrained over a constant distance due to the connection of the arms to the chassis and the mower deck.

Abstract: A lawn rake (100) has a cross head assembly (130) attached to a handle (120). A truncated tee (150) mounted on the cross arm (145) of the cross head assembly (130) receives the handle (120). A plurality of tines (170) is carried by the cross arm (145). The cross arm (145) is tubular and has a plurality of pairs (162) of apertures (164). The apertures (164) are larger than the cross section of the tines (170). The tines (170) are inserted through, and loosely positioned by, the apertures (164). The plurality of tines (170) forms an array (160) that is generally coplanar. The array (160) may form an obtuse angle with respect to the handle (120). Embodiments of the rake include arrays of tines (170) configured to form alternating rows of tines or a curvilinear arrangement of tines. A looped bend (178) formed in the end of each tine (170) distal to the ground engaging tip (176), snaps around the cross arm (145) to pivotally mount each tine (170).

Abstract: To produce a mock yarn which is similar in appearance to a true yarn with respect to the ability to discern the components of the mock yarn after the twist has been imparted to the mock yarn, the rovings or slubbings forming the mock yarn, after drafting separately but parallel to one another in a drafting frame, are subjected separately to condensing and compaction by suction rollers or belts provided with rows of perforations. Thus compacted and condensed rovings are then combined, twisted and wound up as mock yarns. A core thread can be introduced into each roving or into at least one of the rovings upstream of the last pair of drafting rolls or immediately upstream of the condensing unit for a core mock yarn.

Abstract: A spinning machine in which downstream of the drafting frame and as part thereof, beyond the output rollers thereof, a suction roller is provided above the roving and cooperates with at least one counterroller below the roving to condense the roving before it is wound up on a ring-spinning or pot-spinning station.

Abstract: In a gas turbine engine, the exit end of a combustion chamber of annular shape is suspended from the interior wall of the engine casing by an elbow structure which is detachably mounted on a flange by one of its two legs; the resilience of the elbow structure is improved by dove-tail shaped openings provided in the elbow structure with the narrowest section of the openings facing the bend line of the elbow structure to define with the opening of the other leg a gap that enables the elbow structure to function as a leaf-spring.

Abstract: A propulsion system and, in particular, a microthruster for a microsatellite. The microthruster may be formed as a resistojet type thruster formed with a chamber, closed by a diaphragm which acts as a blow-out disk. A fluid, such as an inert gas, is disposed within the chamber. Heating of the gas causes the gas pressure to increase until the diaphragm ruptures, which, in turn, causes the gas to flow out of the chamber, acting as a propellant, and providing a small unit force. The microthruster is adapted to be formed by known batch processing methods with 10.sup.4 -10.sup.6 microthrusters per wafer. The unit of force can be easily scaled by varying the number of microthruster 20 used for an application, the geometry of the chamber 22, as well as the type of fluid used within the chamber, to suit the microsatellite application.

Abstract: A single mode resonant cavity is adapted to absorb energy via a single excitation mode in a plurality of overlapping absorption bands having different respective resonant frequencies, thereby increasing the resonant bandwidth of the cavity. The high Q-factor cavity may form part of a microwave powered catalytic converter for exhaust gas, and has the advantage that as the cavity warms up and physically expands the coupling efficiency between the cavity and a relatively narrow waveband microwave source remains good.

Abstract: A compression ignition type engine, wherein a first combustion where the amount of the recirculated exhaust gas supplied to the combustion chamber is larger than the amount of recirculated exhaust gas where the amount of production of soot peaks and almost no soot is produced and a second combustion where the amount of recirculated exhaust gas supplied to the combustion chamber is smaller than the amount of recirculated exhaust gas where the amount of production of soot peaks are selectively switched between and where the second combustion is switched to the first combustion when the temperature of the catalyst arranged in an engine exhaust passage is about to fall below the activation temperature.

Abstract: A hydrostatic steering device having substantially identical first and second steering systems, each including a pump connected to a steering unit, which is connected to a steering motor by two motor hoses. A steering wheel is common to both steering units. The device includes a change-over valve which has an operation position hydraulically coupling together the two motor hoses of the second steering system, while hydraulically isolating from each other the two motor hoses of the first steering system, and an emergency position hydraulically coupling together the two motor hoses of the first steering system, while hydraulically isolating from each other the two motor hoses of the second steering system. A switching device switches the change-over valve from the operation position to the emergency position, when a fault occurs in the first steering system.

Abstract: A rear exhaust device for pneumatic tool, of which the prime feature is that the pneumatic tool has a handle furnished with a control valve; the control valve is mounted in an intake passage of the handle; a threaded sleeve on outer end of the intake passage is connected with an intake connector of an intake pipe; inner end of the intake pipe has a round conduit to be plugged into a cylindrical hole at one end of an intake passage of the dynamic body portion; between the round conduit on inner end of the intake passage in the handle and the outer body portion, an inner exhaust passage is furnished; a compressed air will flow through passages on both sides of a valve seat, an outer exhaust passage, a pressure-shunting ring, and an outer pipe so as to divide the pressure and to provide good intake and exhaust passages to drive the blades and rotor to rotate.

Abstract: A control system for a hydraulic circuit having a tank, a pump, a supply conduit connected to the pump, a reversible hydraulic motor, an input conduit connected to the motor and an output conduit connected to the motor is disclosed which comprises a first, second, third, and fourth independently operable electrohydraulic metering valve, the second and third valves being disposed between the supply conduit, the first and second valves being disposed between the input conduit, and the third and fourth valves being disposed between the output conduit, a first pressure sensor connected to the supply conduit for sensing a pressure within the supply conduit, a second pressure sensor connected to the input conduit for sensing a pressure within the input conduit, a third pressure sensor connected to the output conduit for sensing a pressure within the output conduit, a speed and directional sensor connected to the motor for sensing the speed and direction of the motor, and a controller connected to the pump, the valv

Abstract: An internal combustion engine includes at least one combustion cylinder and a turbocharger with a compressor for a combustion fluid which is introduced into the combustion cylinder. The compressor has a discharge outlet. An air duct is connected with the combustion cylinder for providing the combustion fluid to the combustion cylinder. The air duct has an inlet opening. An air pipe interconnects the compressor with the air duct. The air pipe has a first end connected with the discharge outlet of the compressor and a second end connected with the inlet opening of the air duct. The second end includes an outwardly projecting shoulder. A flange disposed around the second end of the air pipe includes a recess capturing the shoulder therein and an axial face attached directly with the air duct.

Abstract: A chilling chamber (10) connected to a water reservoir (12) or to a pipe (29) within which water flows has a thermally conductive probe (16) which is connected to the cold side of a thermoelectric device (18), the hot side being connected to a heat sink (20). A tube (30) is coiled about the probe and has one end (28) connected with the water in the storage reservoir or pipe and another end (32) connected to a faucet (34). Water as a heat transfer medium (36) is stored within the chilling chamber (10) about the probe (16) and the coil of tubing (30). The probe cools the heat transfer medium which cools the water within the coil of tubing. A check valve (42) releases air in the chamber compressed as an ice ball forms about the probe. Cold water thus flows out the faucet when the faucet is opened for a short time and the water within the coil gradually raises in temperature to again be cooled by the heat transfer medium.

Abstract: A system and method of active vibration control of an electro-mechanically cooled device is disclosed. A cryogenic cooling system is located within an environment. The cooling system is characterized by a vibration transfer function, which requires vibration transfer function coefficients. A vibration controller generates the vibration transfer function coefficients in response to various triggering events. The environments may differ by mounting apparatus, by proximity to vibration generating devices, or by temperature. The triggering event may be powering on the cooling system, reaching an operating temperature, or a reset action. A counterbalance responds to a drive signal generated by the vibration controller, based on the vibration signal and the vibration transfer function, which adjusts vibrations.

Abstract: A method for densifying the LO2 propellant of a vehicle (10) includes providing a heat exchanger (16) including a chamber (22), and an isolated heater (24) and cooler (26) located within the chamber (22). The method further includes the step of pumping propellant (LO2) (with pump 14) from the vehicle (10) to the first port (24i) of the path of the heater (24), to thereby create a flow of propellant (LO2) through the heater (24) path, and from the second port (24o) of the path of the heater (24). In conjunction with the pumping, propellant (LO2) is coupled from the second port (24o) of the heater (24) back to the vehicle (10), to thereby establish a recirculating flow of propellant (LO2). The chamber (22) of the heat exchanger (16) is filled with at least sufficient cryogenic liquid (LN2) to cover at least a portion of the path of the cooler (26), and preferably the entirety of the path of the cooler (26).

Abstract: A heat radiation shield has an electrically insulating support on which a mosaic of electrically conductive elementary layers is arranged on at least one side.

Abstract: Slush is made from a liquid using slush making systems or according to slush making processes. A jacketed vessel of the processes and the systems has an interior wall that defines an interior space. The interior space comprises a top and a bottom. The interior space has an average overall cross-sectional area taken through a vertical axis extending generally between the top and the bottom. The interior space also has a collection portion having an average collection portion cross-sectional area taken through the vertical axis that is less than the average overall cross-sectional area. The liquid is placed into the interior space and the interior walls are cooled. Slush forms on the interior walls and migrates to the collection portion. The collection portion is located at the interior space bottom when the slush density is higher than the liquid density and the collection portion is located at the interior space top when slush density is less than the liquid density.

Abstract: An apparatus for cooling a product comprises a first evaporator and a second evaporator separate from the first evaporator, a first heat exchanger incorporating the first evaporator and a second heat exchanger incorporating the second evaporator. In operation, the product or an intermediate heat transfer medium is cooled in at least two first stages. During the first stage, heat is withdrawn from the product or the medium by the first evaporator cooling the product or the medium to an intermediate temperature. During the second stage, heat is withdrawn from the product or the medium by the second evaporator further cooling the product or the medium to the desired temperature. Since the product or the medium is partially cooled by an evaporator operating at a higher evaporating temperature than required for achieving the desired temperature, an improved energy efficiency is achieved.

Abstract: Vending machine includes at least one food or perishable item compartment. A sensor is provided for detecting a condition in the food compartment and/or vending machine. The detector senses conditions such as temperature, motion, and the like. Food product bar code data, expiration date data, and product visual data may likewise be collected. Lock-out elements are provided for preventing access to the vended products when detected conditions warrant.

Abstract: An operation control method for a refrigerator after a power-supply comeback due to a power-failure that performs a re-operation according to operation information stored before the power-failure.

Abstract: In a refrigerating/air-conditioning system for a supermarket, a single outdoor unit (60) is connected to a plurality of application units (11, 21, 31, 41, 51), which are connected in parallel to each other. The application units (11, 21, 31, 41, 51) are classified into application units (11, 21, 31) of a first type for forming a two-stage refrigerating cycle with the outdoor unit (60) and application units (41, 51) of a second type for forming a one-stage refrigerating cycle with the outdoor unit (60). The application units (11, 21, 31) of the first type are applied to a freezing showcase (10), a chilling showcase (20) and a storehouse (30), respectively. The application units (41, 51) of the second type are applied to a food processing chamber (40) and a general air-conditioned room (50), respectively.

Abstract: An apparatus and method for a heat pump operating in the heating mode controls the condenser air flow rate and the condenser exiting air temperature depending in a first embodiment on the evaporator ambient temperature, and in a second embodiment, the evaporator air temperature and alternatively the condenser air flow rate or the condenser exiting air temperature, to alleviate a cold blow condition. The apparatus and method operate by sensing the evaporator ambient temperature with a sensor positioned proximate to the evaporator, and when that temperature is below a threshold value indicating a cold blow situation, determining by circuit means a modified condenser air flow rate to achieve at the same time a slower air flow and a higher air temperature, so that the cold blow condition is terminated or at least alleviated.

Abstract: Disclosed is a refrigerator having a cool air dispersing device. A duct housing forming a cool air duct is installed on a rear part of a cooling compartment, and many cool air discharge ports open into the cooling compartment are formed on the duct housing. In the cool air duct are installed many cool air dispersing blades of planar plate shape corresponding to the discharge ports respectively and capable of rotating. The blades control a discharge direction of cool air supplied into the cooling compartment according to a rotational position thereof. The blades have a size similar to the discharge ports, and can close the discharge ports at a predetermined rotational position thereof. While a cooling system is not operating, the discharge ports are closed by the blades, whereby the backflow of air in the cooling compartment toward an evaporator is prevented, and less frost is generated on the evaporator.

Abstract: A method and a container for storing or transporting goods, in particular food products in a frozen and/or chilled state, include a conditioned room where the goods are placed. The room is conditioned by means of a refrigerating medium, for instance solid carbon dioxide, arranged above the room, the refrigerating medium and the room being divided by an insulated panel. A variety of insulated panels can be provided between the refrigerating medium and the room so as to maintain a required amount of cold transfer between the refrigerant and the room. The amount of refrigerating medium can be varied in accordance with specifications such as the assumed duration of the transport/storage, the required storage temperature and a predicted average of the ambient temperature.

Abstract: A device for separating oil from an oil/gas mixture in a refrigeration or heat pump system includes a cylindrical housing circumscribing a central axis with upper and lower end caps. A scroll-shaped separator baffle disposed in the housing defines a flow path extending radially-inward in a spiral manner from a peripheral region of the housing toward the central axis of the housing. An inlet conduit in the upper end cap directs an oil/gas mixture into the housing. An upper baffle plate supporting an upper end of the separator baffle directs the oil/gas mixture from the inlet to the peripheral region of the housing and into the separator baffle. The oil in the mixture generally separates from the gas in the mixture and deposits on the wall of the separator baffle the mixture flows radially inward through the separator baffle. An outlet conduit in the lower end cap aligned with the central axis and extending upwardly into the separator baffle directs the resulting oil-free gas stream from the housing.

Abstract: In order to improve a refrigerant compressor comprising a motor unit which has a motor and a cooling duct for the motor originating from an outer cooling duct connection as well as a compressor unit which has a compressor stage with a compressor stage inlet and a compressor stage outlet and a suction duct originating from an outer suction connection, this duct, like the cooling duct, being guided to the compressor stage inlet, such that the cooling can be realized variably with as few constructional alterations as possible it is suggested that an outer connection unit be provided, on which the cooling duct connection and the suction connection are arranged, that the connection unit have a receiving means and an adjustment part which can be inserted into the receiving means in at least two different positions and that as a result of the various positions of the adjustment part the amounts supplied to the cooling duct connection and the suction connection of the total quantity of the suction gas supplied via an

Abstract: A conventional air separator unit separates nitrogen, oxygen or argon merchant gas to be liquefied. Input pressurized natural gas is processed through a pressure letdown liquefaction system including gas separators for removing moisture and for drying the gas. The dried gas is then separated into large and small gas stream portions wherein CO.sub.2 in the smaller portion is removed. The two portions are passed through a first heat exchanger from which the larger portion is expanded which cools it and then passed through two heat exchangers including the first exchanger, used to regenerate the CO.sub.2 separator and drier and then returned to the input stream.

Abstract: A jewel, such as an earring or other pendant, a broach or a finger ring, may be worn alone or with one of a plurality of readily attachable and interchangeable enhancers. In a preferred embodiment, a finger ring generally comprises a band for encircling the finger and a plurality of attachable enhancers. The band appears to be a conventional ring having any desirable setting and a concave inner side for disposition toward the finger. However, a blind bore in the inner side includes a resilient collar. Each enhancer includes a base having a concave inner side for disposition toward the finger and a convex outer side for mating with the inner side of the band at the bore. A stem attached to the outer side of the base has a bulbous distal portion. Upon attachment of enhancer to band, the stem is inserted in the bore and through the collar which deforms and retains the stem. Front and back ornamental portions, attached to the base, are visible in front and back of the band.

Abstract: A method for producing a high purity synthetic quartz powder, characterized by using a tetramethoxysilane having a trimethoxymethylsilane content of at most 0.3 wt %, and converting it to a synthetic quartz by a sol-gel method.

Abstract: An improved apparatus and method for vacuum fusion bonding of large, patterned glass plates. One or both glass plates are patterned with etched features such as microstructure capillaries and a vacuum pumpout moat, with one plate having at least one hole therethrough for communication with a vacuum pumpout fixture. High accuracy alignment of the plates is accomplished by a temporary clamping fixture until the start of the fusion bonding heat cycle. A complete, void-free fusion bond of seamless, full-strength quality is obtained through the plates; because the glass is heated well into its softening point and because of a large, distributed force that is developed that presses the two plates together from the difference in pressure between the furnace ambient (high pressure) and the channeling and microstructures in the plates (low pressure) due to the vacuum drawn.

Abstract: A method and furnace for heating a glass sheet by lower electric resistance elements (50) supported by a furnace housing (12) below a roll conveyor (40) and by supplying a gas burner heated hot gas flow from a forced convection heater (56) that provides a dominant mode of external heat for heating the conveyed glass sheet from above. The furnace can also be manufactured by retrofitting an electric resistance heater type glass sheet furnace.

Abstract: A method and equipment for adjusting the temperature of glass sheets in a tempering furnace. The tempering furnace (1) comprises rollers (3) for conveying and oscillating the glass sheets (4) during heating, and resistors (5, 6) for heating the glass sheets (4) from above and from below. The temperature of the glass sheets (4) is measured inside the tempering furnace (1) during heating and the dwell time of the glass sheets (4) in the furnace is adjusted based on the temperature measurements. This enables exact control of the final temperature of the glass from the beginning, and the temperature can be kept uniform independently of the measures taken by the operator.

Abstract: In a method of shrinking a tubular optical fiber preform with a doped silica core the preform is placed on a glassmaking lathe to rotate it about an axis, a torch is moved parallel to the axis in front of the preform to shrink it and collapse it in a number of passes, and during an etching pass a mixture of oxygen and a fluorine precursor gas is injected through one end of the incompletely collapsed preform to eliminate a certain layer from the core. During the etching pass, a certain value of the pressure of the gaseous mixture at the end of the preform is determined and the speed of the torch is slaved to this pressure value. Controlling the speed of the torch stabilizes the pressure of the gaseous mixture inside the preform, which longitudinally homogenizes the diameter of the core and the refractive index difference relative to an optical cladding around the core.

Abstract: A method for drawing a mother ingot into a preform for optical fibers comprises providing a mother ingot, subjecting the mother ingot to measurement of a distribution of refractive index along radial directions thereof to determine a ratio of a core diameter to a clad diameter, and comparing the thus determined ratio with a predetermined ratio between the core diameter and the ingot diameter which ensures intended optical transmission characteristics, under which if the determined ratio is insufficient for the intended light transmission characteristics, the mother ingot is further processed until the predetermined ratio is substantially attained, and the resultant ingot is drawn to a preform, or if the determined ratio is acceptable on comparison with the predetermined ratio, the mother ingot is finally drawn.

Abstract: A singlemode optical fiber 700 having very low loss at 1385 nm, and a practical method for making same are disclosed. A core rod 20 is fabricated using vapor axial deposition to have a deposited cladding/core ratio (D/d) that is less than 7.5. The core rod is dehydrated in a chlorine- or fluorine-containing atmosphere at about 1200.degree. C. to reduce the amount of OH present to less than 0.8 parts per billion by weight, and then consolidated in a helium atmosphere at about 1500.degree. C. to convert the porous soot body into a glass. The consolidated core rod is elongated using an oxygen-hydrogen torch that creates a layer of OH ions on the surface of the rod that are largely removed by plasma etching. Finally, the core rod is installed in a glass tube 40 having a suitably low OH content. Thereafter, the tube is collapsed onto the rod to create a preform 60. Conventional methods are employed for drawing an optical fiber from the preform and applying one or more protective coatings 75, 76.

Abstract: A method for high velocity coating optical fibers includes passing a fiber with diameter l at velocity V through a coating container to which liquid coating material with viscosity .mu. is supplied under pressure p. Unwanted bubble formation in the coating is prevented by adjusting one or more of the parameters V, l, .mu., and p using the relationship:S=pl/.mu.Vwhere S is a constant characteristic of the coating container/die structure.