Abstract: Moldings of cross-linked thermoplastic polymers are obtained by the method comprising: melting a cross-linkable thermoplastic polymer admixed with a cross-linking agent by applying a temperature and a pressure insufficient to cause a cross-linking reaction; passing the thus-melted molding material through a first orifice thereby to raise its temperature by a shearing action to an extent that will start a cross-linking reaction; passing the thus-treated melted molding material through a second orifice thereby further to raise its temperature to an extent that will effect a rapid cross-linking reaction of the molding material; and then introducing the thus-treated molding material into a pre-forming die to advance the cross-linking reaction of the molding material and then cooling the molding material by means of a liquid under an elevated pressure.

Abstract: Thermometer probe covers having an extremely thin wall integral tip for enhanced heat transfer are injection molded by unique mold core construction and venting configuration. A tungsten carbide core minimizes core deflection to maintain improved concentricity of core and cavity. Maintainance of concentricity in quantity production apparatus is improved by a combination of relatively loose cantilevered mounting of an end of the core together with a press fit locking of the core upon closing of the mold. Venting of cavity gas during injection of mold material is precisely controlled through symmetrically distributed vent orifices in both the core and the female mold part. Core venting is controlled by a plurality of orifices and a manifold provided by a water cooled core vent pin within a bore of the core.

Abstract: A method for continuously controlling the internal bubble pressure in a tubular thermoplastic film extrusion process which comprises a pressure sensor device which feeds a signal to a pressure controller. In response to the signal the pressure controller feeds a proportional signal to an air valve member which, dependent upon the signal, either increases or decreases air flow into the bubble. A poppet valve, in direct communication with the air pressure inside the bubble, opens to rapidly exhaust air to the atmosphere when the pressure inside the bubble exceeds a set maximum.

Abstract: The vapor and particulate matter emitting equipment is enclosed within walls of an electrostatically charged clear plastic sheet material. The enclosures are connected at their tops to hoods which are connected to ducting leading to an exhaust fan. The vapors are contained within the enclosures until they can be evacuated by the fan. The particulate matter is attracted to the electrostatically charged sheet material.

Abstract: The control cycle for an injection molding machine comprises successive fill, compaction, hold, cure and mold open times. The ram position and mold pressure are monitored at predetermined times respectively after the molding cycle has begun. If the ram position is out of tolerance, the fill pressure is adjusted to compensate for the deviation. If the mold pressure is out of tolerance, the compaction pressure is adjusted to compensate for the deviation in mold pressure.

Abstract: Hydraulic cement or the like is poured into a closed mould under a reduced pressure condition to a level slightly higher than a predetermined level. Coarse aggregate and steel rods are prepacked in the mould. After pouring the pressure in the mould is increased to atmospheric pressure or a higher pressure to force the hydraulic cement above the predetermined level back into the space below the level thus compacting the poured in hydraulic cement. A cushion device is provided for the pouring device. An overflow tank is connected to the mould to observe the level of the poured cement. The pressure in the overflow tank is also decreased during pouring and increased after pouring.

Abstract: In a blow-moulding process, the base of a hollow plastics body is formed initially of convex configuration and then a portion of the base is deformed inwardly to provide a concave area surrounded by an annular support surface. Deformation of the base is controlled in response to an increase of pressure in the mold cavity after termination of venting thereof.

Abstract: An injection molded parison is positioned in a mold cavity having a high length to diameter ratio and being provided with means along the length of the cavity to selectively and alternatively exert positive pressure as an air cushion, or negative pressure as a vacuum, on portions of the parison as the parison is expanded through the length of the cavity. The thickness of the expanding parison is thus controlled so that in subsequent expansion in the blow mold, the finished hollow article will have the desired wall thickness.

Abstract: A method for making tubular plastic material having shaped interlocking profiles thereon for use in reclosable bags by cross-cutting and sealing the material to form the individual bags. The tubular material is made in different diameters of tubes to form bags of different depths, and the speed of delivery of the plastic material and the rate of inflation and delfation is controlled to determine the diameter of the tubing, while the plastic delivery to the profile portion of the die is separately controlled and maintained at a rate, so that, for different sizes and gauges of tubing, the profile will be maintained constant thereby obtaining a profile of optimum size and providing for bags which can be varied in size, but which can each accommodate the same closing and opening slider which fits over the profiles. This method of extruding profile tubes requires fewer changes in extrusion dies.

Abstract: In a process for forming fibers by extruding a spinning dope successively through a layer of inert gas and a tube immersed in a coagulating bath, the tension profile of the yarn passing through the tube is regulated by regulating the pressure of the layer inert gas. In this pressurized quench system, the coagulating liquid is maintained at a predetermined level, despite transient changes in liquid input, by passing both pressurized gas and coagulating liquid through a pipe having an opening at the level to be maintained.

Abstract: Improved extrusion apparatus is shown for the preparation of a rod-like body from a coal-containing particulate mixture. Control mechanisms are disclosed for automatically controlling the throughput resistance experienced by the rod-like (or a developing version thereof) body through a die. Portions of the die wall near the outlet end thereof are adapted for inward displacement in response to these control mechanisms. This embodiment may also be coupled with a longitudinally movable die and control means for adjusting the length of the consolidating coal-containing mixture in contact with the surface of the movable die.