A seal bar for sealing a pouch is provided, wherein the seal bar may comprise a face, wherein the face may be configured to apply heat to seal the pouch, a cavity, wherein the cavity may be configured to form a nozzle shape in the pouch, a seal dot, wherein the seal dot may be configured to apply heat to the pouch, and a heating element, wherein the heating element may be configured to heat the face.

An assembly for use during manufacture of a balloon envelope that includes a table having first and second levels, an indicator disposed on the first level and a sealing component. The first level is arranged to receive a first sheet portion of material. The indicator is arranged along a lengthwise axis of the table to indicate a position for attaching a tendon to the first sheet portion. The second level is arranged to receive assembled gore portions of the envelope comprising the first sheet portion, the tendon and a second sheet portion of material. The sealing component is configured to move along the table and to apply a heat seal to bond together the first and second sheet portions disposed thereon in order to form at least part of a gore portion of the envelope, such that the tendon is arranged proximate to a centerline of the gore.

A machine and method for making bags is described and includes a web traveling from an input section to a rotary drum, to an output section. The rotary drum includes at least one seal bar, having a single sealing zone, and a weakening zone disposed within the single sealing zone. The single sealing zone may be a heated perforator, includes a heating wire. The heating wire may be an NiCr wire stitched into the heater, and be disposed on a cap or on the seal bar. The weakening zone may create a line of weakness that is uniform or varies in intensity. The sealing zone may include temperature zones, cartridge heaters, cooling air, or heated air, or a source of ultrasonic, microwave or radiative energy.

A coated fabric (11), comprising a fabric (12) from polymer tapes (12a, 12b), wherein the fabric (12) is coated with a sealing layer (13), wherein at least a portion of the polymer tapes (12a, 12b) have a breaking tenacity of less than 45 cN/tex, preferably 15 to 40 cN/tex and an elongation at break of more than 30%, preferably of 40 to 90%, and/or wherein the sealing layer (13) is formed from a composition A comprising at least one ethylene/-olefin interpolymer, and wherein the composition has a density from 0.905 to 0.930 g/cc, preferably from 0.910 to 0.930 g/cc (1 cc=1 cm.sup.3), and a melt index (12) from 3 to 20 g/10 min and a bag comprising said fabric; a packaging machine (100) for filling gusseted (220) bags (10, 200) wherein the bag walls (202) of the bags (10, 200) consist of a woven fabric (11) of polymer tapes (12a, 12b) at least in part and wherein each of the ends (203, 204) of the bag wall (202) is provided with a filling mouth (211) for filling, wherein a closing device (125) is provided which is structured such that as the filling mouth (211) is closed a welding temperature of at least 50 Kelvin higher in the region of the gussets (220) than in a center region (223) of the bag wall (202) can be generated.

Aspects of the disclosure relate to manufacturing balloon envelopes for use in high-altitude mesh networks for packet-data communications. As an example, a gore portion may be placed on a table such that the gore portion overlies a groove within the table. A tendon may be placed on the gore portion and within the groove. A portion of tubing may be placed over the tendon. The tubing may have one or more surface openings. Restraining tape is applied over the one or more surface openings in the tubing. A constant force roller is applied to secure the tendon to the gore portion and to secure the tendon to the tubing. As an alternative or in addition to the surface openings, double-sided restraining tape may be placed between the tendon and the tubing. The tubing and restraining tape may prevent undesired lateral and longitudinal movement of the tendon during deployment.

Aspects of the disclosure relate to systems and techniques for inspecting seals for high altitude balloons. In one example, a system may include a reflective surface, a translucent material on the reflective surface, and a movable light source configured to move along the reflective surface and provide light to the reflective surface. The light is provided such that it is reflected from the reflective surface and through the translucent material in order to backlight a balloon envelope seal for inspection. A method for inspecting a balloon envelope seal may include placing balloon envelope material on a table, forming a seal between portions of the material, moving a light over the seal, shining light onto a reflective portion of the table below the seal to backlight the seal, and inspecting the seal using the backlighting of the seal.

Aspects of the disclosure relate to techniques for manufacturing a balloon envelope including a duct for high altitude balloons. In one example, a first sheet of material may be provided. A premade duct may be arranged at least partially on the first sheet of material. The duct may include a first substance on an internal surface. A second sheet of material may be arranged over at least a portion of the duct. A heat sealing device may be applied to the second sheet of material to heat seal the first sheet of material to the second sheet of material. The heat sealing device may be applied over at least a portion of the duct in order to seal external surfaces of the duct to each of the first and second sheets of material and form a balloon gore. The first substance may keep the duct from being sealed to itself.

Aspects of the disclosure relate to manufacturing a balloon envelope for use in a stratospheric balloon system. For instance, a stream of polyethylene mixture is extruded through an extruder in order to orient molecules of polymer chains of polyethylene and to provide an oriented film. The oriented film is passed through an electron beam and thereby crosslinking the polymer chains to provide a cross-linked film. The cross-linked film is heat sealed to form the balloon envelope.

Aspects of the disclosure relate to manufacturing a balloon envelope for use in a stratospheric balloon system using an improved double-bubble blown-film extrusion process with water quenching and electron beam processing. A stream of polyethylene mixture is extruded through an extruder to orient molecules of polymer chains and provide an oriented film. The oriented film is passed through an electron beam, crosslinking the polymer chains to produce a cross-linked film with enhanced mechanical properties. The cross-linked film is heat sealed to form the balloon envelope comprising multiple gores. The resulting balloon envelope exhibits superior characteristics including crystallinity greater than 50%, strength to weight ratio greater than 1 MPa/(dtg/cm.sup.3), thickness less than 1.5 mil, thermal emissivity less than 0.03 at 193K, and optical clarity greater than 95%. The manufacturing process may include water quenching to enhance optical clarity and dual electron beam treatment for uniform crosslinking throughout the film thickness.