Abstract: An injection molding machine for small-sized articles of thermoplastic synthetic resin comprises a hydraulically pressurizable injection head cylinder operable on an injection cylinder of an injection unit for injecting molding material into a mold, a hydraulically pressurizable clamping cylinder operable on one of a pair of mold members of the mold for opening and closing the mold, and a booster operatively connected to both the injection head cylinder and the clamping cylinder for converting pneumatic pressure into high hydraulic pressure to actuate the two cylinders in timed relation to each other.

Abstract: An improved machine for the production of foamed plastic molded parts, including soft foam plastics, i.e. for processing particles without foaming capacity, and including the processing of greatly frothed plastic foam particles, i.e. particles with but little foaming capacity, is obtained in that a pressure equalization system is provided which creates virtually equal pressure conditions while the mold cavity is being filled, i.e. the same overpressure in the material supply line as in the mold cavity. This makes it possible to introduce the foam particles, already compressed in the material supply system, into the mold cavity in a continuous flow by means of an injector, with excess foam particles being blown back into a tank provided in the material supply system by the injector after the mold cavity is filled.

Abstract: A method of monitoring data concerning injection pressure in an injection molding machine is disclosed in which a multipoint sampling technique is used to acquire and store injection pressure reference data in the form of a time varying data curve for a first injection molding cycle. The reference data is used to form upper allowance data which is stored in the form of a time varying data curve having a constant offset from the reference data curve. The upper allowance data is then compared with injection pressure data acquired using a multipoint sampling technique during a second injection molding cycle and an alarm is issued if the data acquired in the second injection molding cycle exceeds the upper allowance data.

Abstract: A molten resin to be injected into a mold cavity in use of an injection molding machine has a temperature, i.e. viscosity difference between at the injection starting point and the injection completing point. In order to eliminate or make small this difference, a high temperature and highly pressurized gas, preferably an inert gas, is preliminarily supplied to and sealed in the mold cavity and the pressure of the supplied gas is continuously controlled in accordance with the position of the screw during the injection molding operation thereby to maintain the temperature of the supplied gas in the mold cavity to be higher than the softening temperature of the molten resin to be injected.

Abstract: A method of mixing polymers, especially rubber by (i) deforming the polymer until it is estimated to attain a first predetermined viscosity, (ii) adding filler and deforming the polymer-and-filler mixture until it is estimated to attain a second predetermined viscosity, (iii) adding oil or plasticiser, and deforming and resulting mixture until it is estimated to attain a third predetermined viscosity, and then (iv) discharging the resulting mixture from the process, where the estimating of each predetermined viscosity is attained by measuring: (1) the mixing torque applied by a mixer during the process at last twice at a fixed mixer-rotor speed and corrected by a reference batch temperature; (2) the rate of change of the torque and (3) the time, or the deforming energy, necessary to reach the torque characteristic of the respective predetermined viscosity. In addition, the ram pressure applied to the mixing chamber is monitored and increased or decreased in response to the cyclic ram movement during mixing.

Abstract: Disclosed is a hydraulically controlled extruder injection molding unit which includes a measured value pick-up for the position of the piston rod of the working cylinder and/or of the injection piston. A pressure control valve which can be switched on is provided in the line leading to the surge chamber of the working cylinder for the piston. A proportionally controlled pressure valve is provided in the line to the other surge chamber, the value being controlled as a function of dropping control values when switching from subsequent pressure to dynamic pressure until the measured value pick-up emits an output signal. The then existing instantaneous value of the dynamic pressure is then added to the preselected dynamic pressure. Consequently, the dynamic pressure phase takes place under a corrected dynamic pressure.

Abstract: A blow molding operation wherein centering rods are associated with preforms at least during the initial portion of the blowing cycle wherein the preforms are primarily axially elongated and wherein the freely suspended lower end of each preform must be guided against radial movement. In order to assure that the associated preform centering rods will remain in centering position with respect to the preforms at all times and will not engage the preforms so as axially to stretch the preforms, a control is provided for coordinating the advance of the preform centering rods with the introduction of blowing gas into the preforms, and thus with the axial elongation of the preforms due to internal blowing pressure.

Abstract: A plastification and injection device for an injection molding machine includes a plunger rod on the pressurized piston coupled to a spindle on which the valve body of a directional control valve is guided axially. The spindle is axially rotatable and is coupled to a stepping motor controlled in accordance with the injection pressure and/or the injection rate. The shaft of a hydromotor driving the plastification and injection screw is guided by means of another directional control valve, the valve body of which is guided so as to slide axially on the shaft. And, this shaft is further coupled to another stepping motor. This, upon completion of the plastification process, the direction of rotation of the hydromotor is reversed in order to close the backflow and, because of the interaction of the other stepping motor and the other directional control valve, the screw moves axially by a predetermined amount to close the backflow.

Abstract: A machine for converting tubular plastic film from flat fold to pleated fold cross section which includes self-contained radio controlled inflating capsule positioned within the tube to inflate it as the gussets are being formed by conventional forming or plowing mechanism.

Abstract: An improved apparatus is disclosed for the production of particulate metal comprising a containment vessel having a sidewall extending to an endwall, a source of metal external to the vessel, nozzle means carried by the endwall, the nozzle means including a central bore and providing communication between the vessel and the external source of metal, the sidewall and endwall cooperating with the nozzle means to seal off the interior of the vessel and the metal particles therein from the area adjacent the source of molten metal, a source of atomizing gas flowing through the nozzle means into the vessel, and means for removing depositions in the bore including a source of purging gas directable into the bore.

Abstract: A method and apparatus for controlling the average thickness (T.sub.1) of a film lamina of thermoplastic, dielectric material having a known density (D.sub.1) and coextruded at a variable extrusion rate with a foam lamina of similar thermoplastic material having a thickness (T.sub.2) and the density of (D.sub.2) to form a thermoplastic laminate is disclosed. The apparatus comprises a first gauge for sensing the thickness of the laminate and for providing a caliper signal (C) corresponding to the thickness sensed and a second gauge for sensing the mass/unit-area of the laminate and for providing a mass signal (M) corresponding to the mass/unit-area sensed. The apparatus further comprises a third gauge for sensing a response to the dielectric material and its distribution in the laminate and for providing a dielectric signal (W) corresponding to the response sensed.

Abstract: A device for monitoring the filling level of the degassing space in an extruder used for processing thermoplastic materials comprises a level detection orifice located in the degassing dome or jacket of the extruder which opening is connected to a conduit. The conduit leads through a regulator device to a gas source. Connected to the conduit, between the regulator device and the orifice, is a pressure sensor such as a pressure difference switch. If the level of molten material in the dome rises above a preselected level, it blocks the opening and produces a back-pressure in the conduit. The switch is automatically actuated by this back-pressure and produces a signal. Appropriate action can then be taken to prevent the further rise of the molten material in the dome and to prevent blockage of the degassing device.

Abstract: A method for forming foamed plastic articles which includes the steps of closing a mold; prepressurizing the mold cavity with gas to prevent premature diffusion of blowing gas from the material injected into the cavity; injecting a short shot of molten synthetic resin material containing a blowing agent into the cavity; venting a portion of the prepressurization gas during the injection step; and venting the remaining prepressurization gas from the mold cavity to a vacuum chamber means to allow expansion of the injected foamable resin material within the mold cavity, the vacuum drawing the resin material throughout the mold cavity. In addition, the vacuum chamber is coupled to the mold cavity through plural spaced passageways so that the vacuum is drawn at various locations throughout the cavity to thereby enhance the complete filling of the cavity with the injected material as it expands.

Abstract: This relates to a label applicator for applying labels to mold cavities of rotating mold units. The label applicator is fixed relative to moving mold units and includes an extensible fluid motor which carries a pick-up head or suction head for moving the suction head in a straight line direction and return. The extensible fluid motor is carried by a shaft for oscillation between a label pick-up position and a label deposit position. The extensible fluid motor is carried by a bracket which, in turn, is carried by a shaft of a rotary actuator which is constructed to oscillate between two fixed positions which are spaced apart a preselected angular distance. There is incorporated with the rotary actuator a decelerator for rapidly, yet smoothly, decelerating rotation of the bracket carrying the extensible fluid motor. Suitable sensor means are provided for timing the actuation of the label applicator in accordance with the position of a mold cavity into which a label is to be placed.

Abstract: A method of extruding and shaping thermoplastic material in which a constant amount of thermoplastic material is continuously fed from a screw extruder to a die by means of a metering pump. The extruder is arranged to continuously receive a constant amount of the thermoplastic material. The metering pump is adjusted to the correct rotational frequency to maintain the pressure of the molten thermoplastic material between the extruder and the metering pump within a predetermined range.

Abstract: To maintain an air or gas bubble forming in a moving tube of plastics material between pairs of squeeze rollers, an air or gas injecting needle is mounted to pivot substantially in a plane containing the centerline of the tube. The needle pierces the tube wall of the bubble when in one rotary position, moves with the tube while pivoting through an arc depending on the depth of needle penetration and is withdrawn from the bubble in a second rotary position.

Abstract: In the operation of a melter/mixer-gear pump system for processing of synthetic thermoplastic materials, the improvement is disclosed which comprises employing the pressure between the melter/mixer and the gear pump as the controlling parameter which affects, in a proportional relationship, the speed of the gear pump, the energy transmitted to and the consequent temperature of the materials passing through said melter/mixer.

Abstract: A method and apparatus for entraining gas as a blowing agent in a thermoplastic melt to provide a foamed thermoplastic extrudate wherein an annular sheet-like flow of gas under pressure is impinged on a tubular configuration of melt to entrain the gas in the melt is disclosed. Also disclosed is an improved method and apparatus for controlling the pressure in the thermoplastic melt.

Abstract: An apparatus and a method is disclosed for continuously producing an indefinite length strip of material in a mold with monitoring of such operating characteristics as product temperature, product pressure, product quantity, film temperature, film pressure, film quantity, reaction time, processing time, product through speed, and the like, together with comparing such monitored values with "profiles" of the desired characteristics to provide for close and quick control of such characteristics. The profile is a comparison standard for each characteristic and defined as a fixed curve representing the desired change of such characteristic with respect to another characteristic, for example, the desired variable temperature along the length of a molding apparatus. Most preferably, foam products are produced.

Abstract: The invention relates to a method for vulcanizing an elastomer, such as tire, fender, sleeve, hose, etc., set in a vulcanizing chamber by use of a mixed fluid comprising a low enthalpy gas and a high thermal capacity thermal fluid, said mixed fluid being obtained by introducing said gas and fluid each independently into the vulcanizing chamber for direct mixing in said vulcanizing chamber, the temperature, pressure and flow rate necessitated for the vulcanization of the vulcanizable elastomer being adapted to be controlled by a temperature sensor and a pressure sensor provided inside the vulcanizing chamber thereby making it possible to obtain proper vulcanization without the conventional impediments of surface bareness or imperfect adhesion in the part of the carcass due to insufficient exhaust in air.

Abstract: An extruder system has an extruder provided internally with a worm. A source of an additive fluid under pressure is connected to a conduit opening into the barrel. An upstream valve and a downstream valve are provided in this conduit and a pressurizable fluid reservoir is provided in the conduit between the valves. The extruder is continuously rotated in the barrel to plastify a resin therein. The valves are alternatively opened and closed, that is one is open when the other is closed and vice versa, so that a fluid first flows from the source through the upstream valve into the reservoir and then from the reservoir through the downstream valve into the barrel to be mixed by the worm with the plastic resin therein. The reservoir can be a cylinder having a piston advanced when the downstream valve is opened to force the charge of additive fluid in the reservoir into the barrel.

Abstract: Hollow fibers, particularly useful as semipermeable membranes in separatory devices such as blood dialyzers, having a non-uniform cross-sectional area along the length thereof. The fibers have recurring points of maximum outside diameter and minimum outside diameter and such points may recur on a regular basis or at random. Fiber wall thicknesses may be substantially uniform or non-uniform. Methods and apparatus for making the fibers are disclosed.

Abstract: An apparatus and method are disclosed for forming a fibrous workpiece comprised of a layer of randomly disposed fibers and adhesive material dispersed throughout the fibers for binding same upon heating and compressing the fibers and adhesive material to define a unitary pad wherein the apparatus comprises a press having a first and a second platen supported for relative movement toward and away from each other, a first and a second mold supported by the first and second platens respectively with the molds having forming surfaces which define the configuration of the pad, and means for heating the workpiece wherein the heating means comprises means for providing hot humid air through the workpiece to provide a rapid penetration and improved heating of the fibers and adhesive material resulting in comparatively high speed forming of the pad with a minimum forming pressure.

Abstract: An internally cooled blown film system, for producing a plastic tube, in which the flow rate of the continuous flow of cooling air through the tube is made directly dependent upon deviation of the tube circumference as determined by transmission and detection of ultrasonic waves from the surface of the tube.

Abstract: This relates to a blow molding operation wherein centering rods are associated with preforms at least during the initial portion of the blowing cycle wherein the preforms are primarily axially elongated and wherein the freely suspended lower end of each preform must be guided against radial movement. In order to assure that the associated preform centering rods will remain in centering position with respect to the preforms at all times and will not engage the preforms so as axially to stretch the preforms, a control is provided for coordinating the advance of the preform centering rods with the introduction of blowing gas into the preforms, and thus with the axial elongation of the preforms due to internal blowing pressure.

Abstract: A sample of polymeric composite material is cured using conventional curing methods. The optimum time during the cure cycle for applying pressure to the sample is determined by standard resin advancement measuring techniques. A dielectrometer monitoring device (15) is then attached to another material of the same type which is cured under the same conditions to develop an analog signal denoting variations in dissipation of the material. The dissipation curve characteristically has a first and second maximum value, with the latter occurring in the general vicinity of the optimum time for applying pressure for a particular frequency. Thus by changing the frequency, the dissipation is shifted along the time axis so that the second maximum coincides with the optimum time for applying pressure. The generation of a readily recognizable and repeatable feature on the analog wave form, a minimum or maximum, is a prerequisite to triggering process control functions.

Abstract: Hollow fibers, particularly useful as semipermeable membranes in separatory devices such as blood dialyzers, having a non-uniform cross-sectional area along the length thereof. The fibers have recurring points of maximum outside diameter and minimum outside diameter and such points may recur on a regular basis or at random. Fiber wall thicknesses may be substantially uniform or non-uniform. Methods and apparatus for making the fibers are disclosed.

Abstract: An assembly at an extruder for controlling the width of a two-layer web flattened from a tube extruded from a rotating or oscillating head of the extruder comprises monitors for detecting the velocity and edge-positions of the web upon transport thereof away from the extruder. A control circuit calculates the deviation of the actual web width from a predetermined width and emits a correction signal relayed via a stationary infrared-radiation transmitter and a receiver on the extruder head to valves controlling the pressurization of the extruded tube by a blower also mounted on the extruder head.

Abstract: A molten thermoplastic resin is extruded in the form of a double-layer cylindrical hollow film with the two film layers being interconnected with each other by a number of spaced legs and is then immediately passed through an annular gap defined by annular side walls of inner and outer vessels in such a manner that the two film layers are in contact with the respective side walls defining the gap. Coolant is supplied to the inner and outer vessels and overflows above the side walls to bring the coolant into contact with the resin. The level of the coolant overflowing above both side walls is adjusted to be equal and also to have a liquid pressure on the extruded resin balanced with a gas pressure supplied in between the two film layers and the legs of the extruded resin.

Abstract: An apparatus for producing tubular plastic films having extremely small variation of flat width in stabilized manner is provided. Said apparatus comprises a blower, a valve for controlling the amount of air, an air reservoir, a connecting pipe for connecting these blower, valve and air reservoir and another connecting pipe which connects said reservoir to the inside of a bubble formed on the tip end of a mold fixed to the outlet of an extruder through said mold to feed or discharge the air into the inside of said bubble continuously in a non-step manner, thereby to keep the inside pressure of said bubble uniform.

Abstract: A control system for a plastic extruder which automatically controls both the melt pressure and the melt temperature of the plastic material at the outlet of the extruder barrel. The extruder barrel is divided into a plurality of heating zones and a zone temperature control means individually controls the temperature of each zone in accordance with predetermined zone temperature set points. A melt temperature control means automatically adjusts certain zone temperature set points such that the actual melt temperature is maintained at its desired value. The speed of a rotatable extruder screw is controlled by a melt pressure control means such that the actual melt pressure is maintained at its desired value. In accordance with the present invention, a separate feedforward controller and separate feedback controller are provided in the melt temperature control loop and in each zone temperature control loop such that independent specification of set point and disturbance responses can be achieved.

Abstract: Material such as panels, boards, and flexible sheets are produced and processed while passing between two or more surfaces at least one of which has a thin layer of pressurized fluid in direct contact with the product. While in this process zone, the item is shaped, coated, smoothed, textured, heated, cooled, compressed, dried, and/or impregnated. For example, expandable resin is deposited in a continuously formed bag of upper and lower sheet material so that the resin may expand and cure as it is drawn in through a fixed rigid mold having upper and lower (and perhaps side) porous material walls through which pressurized fluid is passed to provide a fluid bearing support and molding surface. The temperature, pressure and flow of the fluid is monitored and controlled separately at spaced locations along the length of the mold to control curing rate, foaming rate, surface characteristics and resistance of material moving through the mold.

Abstract: A method for preventing possible vapor explosion in the liquid comminuting process in metal refining comprising comparing pulse pressure generated in the course of liquid comminuting with a fixed reference pressure and adjusting the amount of molten metal thrown into water and the amount of water fed in accordance with the value of comparison.

Abstract: The uniformity of the gauge profile of thermoplastic sheet material is improved by means of a method comprising the detection of areas of non-uniform thickness in the sheet after drawing it away from the extrusion die and the redirection of a controlled portion of the cooling fluid by means of adjustable deflector blades which extend into the flowing stream of cooling fluid and alter the angle at which the cooling fluid contacts and quenches the molten extrudate, thereby allowing additional stretching of thick areas or earlier solidification of thin areas, as appropriate to the problem at hand.

Abstract: A method of molding articles of plastic having an expanded plastic cellular core using a closable and sealable mold having a sealed mold cavity and including at least one mold core extending into the cavity, comprises, directing the plastic melt material containing a foaming agent into the mold cavity under pressure so as to form a flow front of the melt which progresses through the cavity and which spreads out in all directions and flows around the mold core and tends to form a pocket of gas in the vicinity of the mold core, and venting the cavity adjacent the core so as to remove gas from any gas pocket which may be formed in the vicinity of the core. The apparatus for carrying out the invention includes a vent line which extends from the cavity in the vicinity of the mold core out of the cavity and which has a control valve for opening the vent line to vent any gas which forms in the cavity and which might tend to form a pocket after the buildup of a pressure in the mold cavity.

Abstract: In a blown film process for manufacturing plastic film bags, the shape of the film bag being formed is dynamically controlled by sensors provided at specific locations. At these locations, any deviation of the bag shape from the ideal shape will result in significant differences in quality of the produced film bag, or may result in a break of the film bag. Such deviation in shape is prevented by using the output signals from the sensors to control various process parameters.

Abstract: A control device connected to rotational speed measuring means for an extruder screw, to a filling level monitor in a degassing opening of the extruder, to a cut-off in a filling container for the extruder, to vacuum means connected to the degassing opening and to a source of gas under pressure such that upon receipt from the speed measuring means or the filling level monitor by the control device of an indication of probable filling of the degassing opening with melt, the control device closes the cut-off, disconnects the vacuum means from the degassing opening and connects the gas pressure source thereto.

Abstract: A control system for a plastic extruder which automatically controls both the melt pressure and the melt temperature of the plastic material at the outlet of the extruder barrel. The extruder barrel is divided into a plurality of heating zones and a zone temperature control means individually controls the temperature of each zone in accordance with predetermined zone temperature set points. A melt temperature control means automatically adjusts certain zone temperature set points such that the actual melt temperature is maintained at its desired value. The speed of a rotatable extruder screw is controlled by a melt pressure control means such that the actual melt pressure is maintained at its desired value. In accordance with the present invention, a separate feedforward controller and separate feedback controller are provided in the melt temperature control loop and in each zone temperature control loop such that independent specification of set point and disturbance responses can be achieved.

Abstract: A coupling circuit for the feedback loops of foil-thickness control circuit, a calibrator height-adjusting control circuit, a calibrator diameter-setting control circuit and a balloon-filling control circuit interlocks the control circuits and shifts the responses thereof upon start-up of a film or foil blowing apparatus. The latter also includes the usual blowing heads, connected to a worm extruder, the calibrating basket, the balloon-flattening device, the drawing rollers and the winding device which rolls up the flattened web of blown film.

Abstract: The stability of a flash fibrillation process for converting thermoplastics materials into fibrils by flash extruding a hot pressurized dispersion of thermoplastics material in liquid through an orifice is improved by inserting a pressure-responsive valve in the orifice which ensures the dispersion is at a specified minimum pressure before it is extruded through the orifice. The minimum pressure should be sufficient to ensure the liquid does not volatilize prior to its extrusion through the outlet.

Abstract: A method and system for cooling an injection molded plastic article by forming a portion of a mold cavity of fluid permeable porous material that communicates with a cooling liquid passageway and subjecting the cooling liquid to different pressures to vary the flow of fluid through the porous plug.

Abstract: A centrifuge and centrifugal process are disclosed for prefoaming liquid polyurethane-foam generating reactants prior to introducing the reactants into a mold. A preferred embodiment of the invention is adapted to produce continuously slabs of polyurethane foam of substantially rectangular cross section.

Abstract: A process for controlling a vessel for a repeated pouring of a liquid under low pressure into blind sand moulds. The process comprises after each pouring, lowering the liquid in the pouring tube only to a level which is equal to or substantially equal to a constant predetermined level in the vicinity of the outlet of the tube. According to the invention, the level of the liquid in the tube and the pressure of the driving gas prevailing in the vessel are measured directly and the inlet and exhaust of the driving gas are controlled as a function of these measurements so as to ensure, for all the pourings, a pressure rise time and a pressure drop time which are predetermined and substantially constant. A device is described for carrying out this process.

Abstract: Control apparatus for automatically maintaining the desired blown tube diameter in the blown plastic film process where the blown tube is internally cooled by a gas flow into and out of the interior of the tube. A by-pass duct having a by-pass damper is provided on either the inlet or exhaust duct by-passing the inlet or exhaust duct damper respectively and this by-pass damper is controlled by tube diameter sensors. By thus controlling only a small percentage of the inlet or exhaust flow a very fine and stable control is achieved. Control apparatus is also provided to maintain the by-pass damper in its optimum operating range.

Abstract: Blown film sheeting is manufactured using a tubular film blowhead fitted with internal and external air cooling devices, a collapsible frame for flattening the tubular film and a slitting device positioned above the frame for producing the film in sheet form just prior to removal of the film on dual takeoff rolls. The invention is particularly adaptable for thermoplastic polyethylene film.

Abstract: An improved "pre-autoclaving" process for the formation of fiber-reinforced calcium silicate hydrate bodies (such as thermal insulation) is disclosed. The improvement comprises first cooling the crystal slurry from the reactor in a heat exchanger and then metering the cooled slurry through a venturi to reduce the pressure and control the flow rate.

Abstract: An improved process for making a gas diffusion electrode which comprises heating of the mixed electrode material prior to forming the electrode. Because of the stickiness or self adhesion characteristics of the electrode mixture, the invention includes special transport apparatus having a fluidized bed that uniformly disperses the sticky electrode material onto a conveyor belt for forming the electrode without subsequent heating.

Abstract: Plastic blown ware is made by expanding a molten plastic tubular blank into contact with the wall of a mold cavity. This invention evacuates air from the part of the cavity around the outside of the blank to increase the pressure differential across the tube wall during the blowing period and to help prevent the plastic from pulling away from the cavity wall during cooling and shrinkage. The invention makes blown ware by compounding the plastic with a blowing agent and by controlling the bubble size and wall thickness by changing the pressure on opposite sides of the blown article to whatever pressure will permit the gas bubbles and the plastic to expand to the desired size during cooling and setting of the plastic.

Abstract: There is disclosed a method of and apparatus for use in the production of shaped, high polymeric articles, particularly yarns, in which natural, thermo-plastic high polymeric material and a coloring agent are mixed together and the delivery of the coloring agent for mixing is controlled in dependence upon the rate at which the mixture is processed.

Abstract: Method and apparatus for curing a tire having an internal cavity using as heat and fluid pressure media first steam and then cooler inert gas. The time rate of pressure loss in the cavity is determined in each tire curing cycle by closing the cavity so as to form a completely closed chamber for a test time less than the normal cure time for the tire. Pressure loss during the test time is monitored and if determined to be at a greater than tolerable rate a warning device is actuated and means for loading a next tire into the mold is rendered inactive.