Abstract: A vibration applying apparatus associated with an injection molding machine for applying vibrational repetitive movements to a melt of molding materials includes a rod having a tip end received inside a heating cylinder and disposed in the proximity of a nozzle of the heating cylinder, a stationary guide supporting the rod such that the rod is movable back and forth, a rotating shaft being orthogonal to the rod, a drive motor for rotating the rotating shaft, and a cam mechanism acting between the rotating shaft and the rod so as to convert rotary motion of the rotating shaft into linear reciprocal motion of the rod. With the apparatus thus arranged, the tip end of the reciprocating rod applies vibrational repetitive movements to the melt of molding material, thereby lower the viscosity of melt. The frequency of vibrational repetitive movements can be varied by changing the rotational speed of the drive motor.

Abstract: A continuous mixer in which a pair of left and right rotors 4 are rotatably inserted into a chamber 2 having a feed port 13 and a discharge port 14 for materials at both axial ends, respectively, a gate device 17 for adjusting the polymer flow resistance of the materials is provided halfway in the axial direction of the chamber 2, and a first and a second mixing portions 19, 21 are formed at portions, respectively, of the rotors 4 positioned upstream and downstream of the gate device 17, wherein a forced feed means 23 for forcibly post-adding the materials is connected to a portion downstream of the gate device 17 in the chamber 2 and upstream of the discharge port 15.

Abstract: Devolatilization of molten polymer is carried out using a vertical static mixer which opens directly into a flash tank. Expansion of a stripping agent injected at an inlet of the static mixer occurs in the static mixer and the continued shearing causes disengagement of the vapor from the polymer, so that expansion is complete before the polymer enters the flash tank and stripper and volatiles are removed by a pump and condenser arrangement which holds the flash tank at a reduced pressure. Polymer outlets are in the floor of the flash tank and have metering pumps at their bottom end.

Abstract: An injection molding machine includes an injection molding cylinder with a material supply at one end and an injection nozzle at the other end and a material conveyance unit attached to a drive and movable in the injection molding cylinder. The injection molding machine also includes a vibration element for inducing a flow of melt within the injection molding cylinder for homogenizing the melt.

Abstract: A method for controlling a screw injecting apparatus having a heating cylinder and a screw slidably and rotatably received in the heating cylinder and designed to carry out a plasticizing-metering phase in which a predetermined amount of a molten material is accumulated forwardly of the screw by plasticizing and kneading a raw molding material via the screw and the heating cylinder, a waiting phase in which the screw is held inactive for a period between completion of the metering and subsequent injection of the molten material, and an injecting phase in which the molten material is injected. The method comprises the step of causing the apparatus to vibrate the molten material at a predetermined low frequency axially of the screw during the plasticizing-metering phase. By vibrating the molten material at a low frequency during the relatively long plasticizing-metering phase, the viscosity of the molten material can be reduced.

Abstract: An injection molding process wherein the times of heating to melt a resin are reduced to minimize the thermal hysteresis and to decrease the deterioration of physical properties caused by the thermal hysteresis, so that high quality information recording disks may be produced. A molding process wherein the plasticating and the injection and filling of a material resin are carried out in separate cylinders, allows constant molding for a long period of time. A material resin such as polycarbonate is supplied without predrying to an injection apparatus for a first time molding. Resin is kneaded by the apparatus while volatile components are heated to be vaporized and exhausted through a vent port. An inert gas atmosphere is provided within the cylinder to prevent the material resin from being oxidized. Since predrying can be dispensed with, the thermal hysteresis will be extremely small and the deterioration of the resin caused by such heating may be suppressed.

Abstract: A mixing process apparatus for discharging polymer material into a mold comprising a resin passage having an inlet for receiving polymer material and an outlet for discharge polymer material for molding, a first and second chamber communicates with said passage with each of said first and second chambers having a variable volume, said variable volume varying from a fill position for holding a predetermined volume of said polymer material to a discharge position for emptying polymer material, said first and second chamber being adapted for movement to transport said polymer material from a first mix position where one chamber is in a fill position and the other chamber is in an emptying position to a second mix position wherein said one chamber moves to an emptying position and said other chamber moves to a fill position, said first and second chamber being adapted for discharging said polymer material for molding when each of said chambers is in an emptying position.

Abstract: The invention comprises a plasticating machine for the working and forcing of plastic material into a mold, the machine including an elongated barrel housing having a first or proximal end and a second or distal end, and an elongated screw shaft with a screw flight therearound, the screw shaft being rotatably supported in the elongated barrel housing, for the working of plastic between the screw shaft and the elongated housing. At least one delivery conduit is generally longitudinally arranged within the wall of the housing. The delivery conduit with the housing wall may be arranged to heat or cool the screw and any plastic being worked therethrough. In a further embodiment, it may permit delivery of a medium within the wall, from an upstream location of the housing, into the primary flow path of any plastic being driven from the machine and into a mold.

Abstract: A process for the manufacture of cooked cereals or dry pet food which comprises preparing a mixture of water and a dry premix mainly comprising cereal flour or semolina, cooking the mixture and extruding it by pressing it through an extrusion die with the aid of a gear pump.

Abstract: An injection molding process and apparatus to manufacture asphalt-based products which utilizes a heated mixing chamber to continuously blend molten thermoplastic polymer and asphalt to form an injection moldable composition.

Abstract: An apparatus and a method for molding of polyester articles having low acetaldehyde content directly from a melt without intermediate solidification of the molten polyester. A melt to mold process is used wherein an acetaldehyde stripping agent is mixed into a polyester melt before devolatilization in a flash tank. The devolatilized polyester is pumped out of the flash tank and injected into a mold, thus forming a shaped article. The apparatus may include one or more flash tanks in one devolatilization line, or multiple devolatilization lines may be used stemming from one main polymerization reactor. The final shaped article should contain less than 10 ppm of acetaldehyde.

Abstract: The present invention relates to an apparatus and method for producing molded polyester articles. More particularly, the invention concerns an apparatus and method for continuously producing molded polyester articles having low acetaldehyde content from a melt prepared by continuously reacting polyester precursors. The polyester is prepared and formed into useful shaped articles in a single, integrated, continuous melt-to-mold process without an intermediate solidification of the melt.

Abstract: A charging barrel and screw as well as their associated components for carrying out the processes of plasticization, injection and pressure maintaining of the polymer are all disposed in the inner cavity of a metal moving body driven to rotate pulsatorily by an electromagnetic winding. At the time when the screw and the metal moving body are simultaneously rotating pulsatorily, the screw is at the same time making axial pulsative displaments, so that the processes of plasticization, injection and pressure maintaining are all carried out in a periodic oscillating state. This type of injection moulding method and apparatus have the advantages of small volume, light weight, low manufacturing cost, low energy consumption, low noises, wide adaptability to materials and excellent quality of the moulded products.

Abstract: In one embodiment, the present invention relates to an apparatus for the sequential assembly of a sandwich-type comestible product, such as an ice cream sandwich, and comprises an essentially horizontal conveyor, sequentially placed wafer dispensing assemblies and an extrusion assembly for the dispensing of a regulated amount of a comestible material. Wafer dispensing is controlled by a screw drive. Extrusion is accomplished by a front-loadable rotary head extruder. The wafer dispensing assemblies and the extruder are mounted in cantilevered fashion on a vertical wall, thereby facilitating the ease of repair, removal for retrofitting and cleaning. In addition, the extruder and the wafer dispensing assemblies are individually removable and may be replaced with like components of differing internal diameter, to accommodate the preparation of sandwich-type comestible products of differing size and shape.

Abstract: A mash feed treatment system including a mash feed conditioning apparatus connected in series with a roller mill and a pellet mill. The mash feed conditioning apparatus includes a housing having an interior and an inlet and outlet, a shaft mounted within the interior of the housing having an internal cavity, and mechanisms for rotating the shaft to convey feed within the interior and for introducing steam into the interior via the cavity of the shaft. The shaft and the housing preferably include pressure containment mechanisms for maintaining superatmospheric pressures within the cavity and the interior respectively.

Abstract: An innovative method and apparatus for synchronizing the flows of molten polymer or similar materials in molding systems which utilize manifolds to direct flow into one or more cavities of an injection mold. The apparatus utilizes intermeshing positive displacement, interconnected gearing systems similar to positive displacement gear pumps in hydraulic systems. These positive displacement gear mechanisms are placed in each parallel flow channel such that all flow in each channel passes through a gear mechanism. Each of the parallel pumps are connected together directly via a shaft or indirectly using hydraulic motors, stepper motors, or other motors to synchronize the parallel flows. Each flow can be different to allow the directing of flows in complex tools or when molding parts in family molds.

Abstract: Angled scraper blades provided on the end of a screw shaft of an extruder provide thrust for propelling polymer toward the die opening of the extruder. The scraper blades help prevent trapping of polymer between the shaft and the die plate of the extruder, which trapping can lead to scorching, burning or break down of the polymer.

Abstract: A mixing apparatus for continuously generating a homogeneous mixture of a polymer and a less viscous fluid is provided. The mixer includes means for continuously injecting a viscous polymer into a pressure vessel; means for continuously injecting a lower viscosity fluid into the pressure vessel; means for continuously injecting a plasticizing agent into the viscous polymer entering the pressure vessel; high shear centrifugal mixing means within the pressure vessel for mixing the polymer and the less viscous fluid; drive means for rotating the rotational mixing means; heating means for maintaining the temperature of the substances being mixed in the pressure vessel at a desired mixing temperature; and means for continuously discharging a homogeneous mixture of the polymer, the plasticizing agent, and the less viscous fluid from the mixer.

Abstract: An extruder device includes a rotor rotatably received in a housing and a tube secured to the rotor and having a helical screw formed in the outer portion. A screw member is engaged in the bore of the rotor and secured in the tube and rotated in concert with the tube and the rotor. The material to be extruded is supplied onto the tube and moved by the helical screw and then by the screw member. The helical screw includes a pitch greater than that of the screw member for allowing the helical screw of the tube to squeeze the material.

Abstract: An injection molding process for forming high strength, long fiber-reinforced thermoplastic resin, and for holding damage to the pellet-shaped thermoplastic resin to a minimum even when being plasticized, and maintaining the fiber length of pellet-shaped fiber bundles while unwinding the fibers and melting the resin. After the long fiber-reinforced thermoplastic resin has been heated and melted, pressure is applied to unwind the long fiber-reinforced thermoplastic resin while melted, and injection molding then performed.

Abstract: A supplying device and method make use of a cylinder and a rotary member rotatable in the cylinder for introducing and forwarding a band- or string-shaped raw material having a regular section along a fluidization passage formed between the cylinder and rotary member, while fluidizing the raw material into fluid material with frictional heat produced by the rotation of the rotary member. The fluid material is continuously discharged from a nozzle disposed on the cylinder to various processing devices such as a synthetic-resin molding machine or machine tool.

Abstract: By embodying a feed screw (17) for glass fiber reinforced polyester material with a hollow shaft, it is possible for the injection piston (11) for an injection unit (9) to have a compact structure so as to be passed through the feed screw (17). To process even viscous polyester compositions gently, the injection piston can be equipped with a plasticizer screw and an associated plasticizer motor.

Abstract: An injection molding apparatus has a plasticizing space formed in a substantial cone or disk shape between a heating cylinder and a screw, into which molding resin is introduced. The molding resin in the plasticizing space can be maintained in its uniformly plasticized state by continuously rotating the screw during an injection molding operation, thus increasing the efficiency of injection molding. The heating cylinder and screw can readily be assembled because the heating surface of the heating cylinder and the plasticizing surface of the screw are formed in substantial cone or disk shapes.

Abstract: A mixing head for a molding machine includes a mixing chamber into which reaction materials are injected from nozzles communicating therewith, toward a closed end of the chamber and at acute angles with respect to the longitudinal axis of the chamber, the angles' apexes lying toward the closed end. The streams of injected material impact and mix, before entering an area of turbulence between the closed end of the specifically dimensioned chamber, and the points of communication where they are preliminarily reacted. Subsequently the material leaves the chamber by passing back through the point of impact, effecting further mixing. The doubly mixed material thereafter proceeds to a discharge passageway prior to entering a mold.

Abstract: A pellet mill for pelleting feed product, has a pelleting die with a plurality of extrusion holes for extruding the feed product; rollers, rotatable relative to the pelleting die, for forcing feed product through the extrusion holes; provision for intensively mixing and shearing the feed product before introducing the feed product to the pelleting die; and a device for positively conveying the feed product into the provision for intensively mixing and shearing.

Abstract: An improved temperature control system using a state controller with two degrees of freedom to regulate the temperature of the barrel of an injection molding machine is disclosed. The control system divides the temperature of the barrel into longitudinally-extending zones and radially extending layers within each zone. Heat transfer calculations which include the effects of heat transfer between all the layers within the zones are performed for a set time in the future to accurately determine the heat needed from the heater band to reach the operator set point temperature. The duty cycle for the heater bands is thus accurately set to give a more responsive and accurate control than heretofore possible. The controller additionally includes factors for accounting for heat disturbances present in the injection molding process. In addition each system is calibrated for each machine to insure accurate formulation of machine specific parameters such as heat transfer co-efficients used in the control.

Abstract: In the production of a flowable reaction mixture of at least two flowable, also not readily miscible, reaction components which react completely with each other to form solid substance or foam material, a rapid abatement of the mixture flow is achieved with a compact type of construction after causing throttling at the discharge of the mixing chamber.

Abstract: Dough intended for use in producing bakery products is homogenized and advanced to extrusion nozzles where it is cut into successive pieces that fall onto a moving conveyor. The pieces are of precisely uniform weight because a constant pressure is maintained on the dough as it is forwarded by a metering pump toward the nozzles. Apparatus for achieving such result includes an auger, a developer positioned downstream from the auger, and a transition chamber fed by the developer and located upstream from the metering pump. A pressure-measuring monitor serves to control the rotational speed of the auger, thereby maintaining the dough under constant pressure within the apparatus.

Abstract: Apparatus for the manufacture of an ultra-high molecular weight polyethylene thin-wall pipe which is uniform in thickness and free from a folded mark. The ultra-high molecular weight polyethylene thin-wall pipe is manufactured by supplying ultra-high molecular weight polyethylene into and melting and kneading, continuously extruding the molten substance of the ultra-high molecular weight polyethylene from a die connected to a screw of the screw extruder to form a cylindrical roughly shaped article, and diametrically expanding the cylindrical roughly extruded article by a tapered core and taking up.

Abstract: A die for co-extruding structural shapes is provided with a central cylindrical duct through which the molten polymeric material destined to constitute the central core of the structural shape flows, and a conical gap, coaxial with the central duct, into which the polymeric coating material is fed which will constitute the outer skin of the structural shape.

Abstract: A plasticizing apparatus (10) including a barrel (12) having a bore (14) therethrough. An auger (24) and a rotor (30) are positioned in the bore, each extending from opposed ends (16, 18) of the barrel (12) and having ends (26, 34) that are substantially flush. The auger (24) conveys particulate plastic material along the bore (14), the plastic being frictionally melted before passing the auger discharge end (26). The rotor (30) is provided to uniformly heat the melted plastic. Auger (24) and rotor (30) each are associated with independent means for rotating (28, 32) and means for controlling the speed of rotation (50, 52). The speed of rotation of the auger (24) controls the flow rate of plastic through the bore, and the speed of rotation of the rotor (30) controls the temperature of the melted plastic.

Abstract: In the manufacture of a battery cell, a shear thinning cathode material that has been mixed to a homogeneous state is transported to an extrusion opening while being subjected to a non-decreasing shear stress. The shear thinning cathode material is extruded onto a conductive substrate material at a constant rate. An electrolyte material is applied over the shear thinning cathode material, and an anode material is applied over the electrolyte material.

Abstract: In the production of foamed plastic articles using a screw extruder, it is known to introduce a gaseous foaming agent into the plastic while the latter is passing through the extruder. It has been found that a foamed thermoplastic with pores or cells of uniform size and distribution can be produced by passing a gaseous foaming agent, e.g. nitrogen gas through a central passage extending substantially the entire length of the extruder screw, discharging the agent into the thermoplastic proximate the discharge end of the extruder, and mixing the foaming agent with the plastic immediately prior to discharge of the mixture into a mold.

Abstract: A machine for molding a starting crystalline saturated polyester resin such as polyethylene terephthalate includes a device for first drying and then preheating the starting resin to a temperature above its melting point to lower the viscosity of the resin to such an extent that the resin is not substantially degraded in the compression section of the molding machine. A feed section is provided for quantitatively feeding the molten starting resin to the main body of the molding machine. Accordingly, the starting resin is molded into a desired shape in a molding machine under conditions such that the crystallization temperature of the resulting molded article is within 20.degree. C. of the crystallization temperature of the starting saturated crystalline polyester resin.

Abstract: An improved method for injection molding including the steps of plasticizing a shot of molding material with the extruder running at a high rpm, transferring the shot to an accumulator means with the extruder running at a low rpm, and injecting the shot into a mold cavity.

Abstract: A compact and precision extrusion system for extruding strips of rubber compounds with profiles of accurate dimensions. Strips of rubber compound are uniformly heated and mixed in an extruder and then passed through a low pressure drop strainer to remove foreign matter. The strained compound then is fed directly into a gear pump which delivers precise volumes of the rubber compound immediately into the spread chamber of an extrusion head after which it passes through a die to form a precise strip of the rubber compound. The strainer and extrusion head are movably mounted with respect to the gear pump for axial separation from the gear pump for easy removal of the rubber compound from the various components of the system to facilitate compound changes. A control system regulates the speed of the extruder to provide a near constant pressure at the entrance port of the gear pump to precisely regulate the rate of extrusion of the compound from the extrusion head.

Abstract: A highly viscous or dough-like material, especially glass fiber-filled polyester, polyamide or polypropylene is fed from a rotating funnel via a feed worm lying along a generatrix of the funnel directly into an extruder or an injection molding cylinder and without passing through an elbow or other jacket. The system is thereby able to operate at reduced pressure with least damage to the fibers and reduced drive energy for the feed worm or screw.

Abstract: A process and apparatus for injection molding of plastic material incorporate a perforated member for melt filtering and/or melt mixing during metering of plasticized material. The perforated member may be of a disk form mounted to a screw plunger provided within a machine body with the perforations arranged around the screw plunger. Impurities accumulated at the perforated member may be purged by rotating the screw plunger from a nozzle connected to the machine body via an annular recess formed at an inner surface of the machine body or directly from the machine body per se via a radial hole formed therein, when the screw plunger is in a predetermined position preferably in the most forward position, where the recess or the hole is located in the vicinity of the perforated member.

Abstract: In a process for producing a halogenated polycarbonate molded article from a powder or pellets of a halogenated polycarbonate resin or composition thereof by means of injection molding using an injection molding machine, the improvement wherein the injection molding machine comprises a cylinder whose inner circumferential wall being made of a corrosion-resistant and abrasion-resistant alloy comprising alloy component (1), (2), or (3) given below, and a screw part made of a steel having a metal coating formed by hard chromium plating or hard nickel plating or made of SUS420, SUS440, Hastelloy C, or a steel comprising alloy component (4) given below:______________________________________ Alloy component (1): C: 0.5-2 wt % Si: 1-5 wt % B: 0.5-5 wt % Ni: 10-25 wt % Cr: 20-35 wt % W: 10-25 wt % Cu: 0.5 -5 wt % Remainder: Co and unavoidable impurities, Alloy component (2): Si: 0.2-4 wt % Mn: 0.

Abstract: An extrusion method for obtaining a long phenolic resin pipe having excellent heat resistance by using an extruder having a screw, a cylinder, a die and a mandrel, the mandrel being inserted into a through-hole formed in the screw along the screw axis and protruding into the die along the screw axis, the die satisfying the following formulasR.sub.1 /R.sub.2 =0.25.about.1.0S.sub.1 /S.sub.2 =0.1.about.2.5where R.sub.1 is an outside diameter of the die flow path at the die outlet, S.sub.1 is a cross-sectional area of the die flow path at the die outlet, R.sub.2 is an outside diameter of the die flow path at the die inlet, and S.sub.2 is a cross-sectional area of the die flow path at the die inlet, and the inclination of the outer periphery of the die flow path portion from the die inlet to a starting point of the uniform flow path portion having the same cross section as the die outlet is not larger than 35.degree.

Abstract: A bimetallic cylinder of steel having an alloy inlay which includes chromium boride in a matrix of iron alloy containing carbon, silicon, nickel and copper. The chromium boride imparts wear resistance to the inlay and relatively high contents of chromium, nickel and silicon and the presence of molybdenum and copper in the alloy make it resistant to corrosion. The cylinder is useful for injection molding and extrusion of plastics.

Abstract: An apparatus (20) for batch molding open-cell soft polyurethane foam within a mold (22a,22b,104) is provided by introducing into a mixing chamber (26) of a mixing pot (24) a highly activated polyol component and an isocyanate component which are mixed and permitted to foam to provide upward expansion in a viscous state through an upper outlet (28) by free rise that fills the mold (22,104). Such batch molding provides "one age of foam" that enables molding to be performed which was not previously possible. Both a rigid mold (22) and a flexible mold (104) can be utilized. The mixing pot (24) includes a mixer 38 preferably embodied by a rotatable screw (74) that is moved axially to purge the mixing chamber (26) of foam after each cycle.

Abstract: An apparatus for manufacturing an optical disk substrate having a foreign-substances index of not more than 1.times.10.sup.5 .mu.m.sup.2 /g, an optical information-storage medium wherein the substrate has an information-recording layer, includes a cylinder with a liner and a screw coated with TiC and TiN.

Abstract: An extrusion device for processing thermoplastic plastics material and rubber has a housing and primary screw means rotatably mounted therein. The device includes a discharge zone in which a sleeve member provided with external flights is mounted on a bearing shaft so as to be rotatable about its longitudinal axis, which sleeve member is drivable by the primary screw means but in an opposite direction thereto so as to increase the discharge pressure acting on the material being processed.

Abstract: The invention is directed to an extruder 1, particularly a small extruder for transferring plastics material in strand form to a plasticized state. In order to improve the homogeneity, it is provided that the screw portion 7 serving for drawing in be constructed simultaneously for granulating the plastics material which is then melted in the further plasticizing portion 6. The special arrangement of the draw-in channel 12 in relation to the configuration of the screw profile of the granulating screw portion 7 causes the separation and granulation of the drawn in plastics strand, so that material which is already granulated is fed into the plasticizing screw portion 6 projecting into the cylindrical bore hole 10 of the housing portion 9 and can then be transferred into the desired state along a short distance.

Abstract: An extrusion apparatus is provided for the mixing and extrusion of thermo-plastic and thermo-setting materials and the pelletizing of thermo-set materials, in which a rotor member is rotatable within a barrel member. The apparatus is articulated into three sections including a barrel entrance section, a forcing section and a metering section. Each section is provided with helical rotor extrusion grooves, and is followed by a circumferential barrier and a rotor to barrel to rotor transfer zone. The circumferential barrier is provided with a clearance, barrier top to barrel bore, designed to pass fluent material and retarding the over-size and less fluent material. The leading edge of the circumferential barrier is provided with multiple dual purpose plows which, direct the fluent material down-stream and the over-size and less fluent material up-stream for additional working.

Abstract: A dynamic mixing system and method intensively mixes thermoplastic melt with other ingredients and entrains gas as a blowing agent in a thermoplastic melt so as to provide a foamed thermoplastic extrudate. The dynamic mixing system includes a plurality of mixing balls disposed circumferentially about the surface of a cylindrically shaped spindle which is rotatably disposed within a barrel, such that upon rotation of the spindle the mixing balls rotate in a planetary manner so as to intensively mix a flow of thermoplastic melt, for example, to entrain a blowing agent in the melt.

Abstract: A seal on a drive shaft of an extrusion machine having a housing, is provided by a sealing chamber through which the shaft, for example the drive shaft of the shear spindle, extends in entering the housing, and a sealing screw thread on a portion of the shaft in the sealing chamber, the sealing screw thread having a screw direction for propelling material toward the interior of the housing. Sealing material in the form of granular plastic material is fed to the sealing chamber at a controlled rate by a device having a storage container for the granular plastic material, the bottom of the container having a funnel feeding the granular plastic material into an elongate cavity which communicates with the sealing chamber and in which the piston rod of a piston-cylinder unit is reciprocable to propel the granular plastic material into the sealing chamber. The pressure inside the sealing chamber is sensed and the operation of the piston-cylinder unit is controlled to maintain the pressure approximately constant.

Abstract: A process for producing a polycarbonate molded article having a low dust level from a polycarbonate resin in the form of a powder or pellets by injection molding using an injection molding machine. The injection molding machine includes a cylinder whose inner circumferential wall is made of a corrosion- and abrasion-resistant alloy from alloy components (1), (2), or (3) given below and a screw part made of a steel having a metal coating formed of hard chromium plating or hard nickel plating or formed of titanium carbide or tungsten carbide, or is made of SUS420, SUS440, Hastelloy C, or a steel of alloy component (4) given below:Alloy components (1):C: 0.5-1.5 wt%Si: 1.0-2.0 wt%B: 0.5-2.5 wt%Ni: 10.0-20.0 wt%Cr: 20.0-30.0 wt%W: 10.0-20.0 wt%Cu: 0.5-2.0 wt%Remainder: Co and unavoidable impurities,Alloy components (2):Ni: 0.0-2.0 wt%Cr: 5.0-15.0 wt%Fe: 0.0-1.0 wt%Mn: 0.1-2.0 wt%Si: 0.2-4.0 wt%B: 2.0-4.0 wt%Remainder: Co and unavoidable impurities,Alloy components (3):Cr: 5.0-10.0 wt%Co: 5.0-40.0 wt%Fe: 0.0-10.

Abstract: An improved apparatus for varying the pressure within a screw channel which apparatus includes a shaft having a helical flight defining a channel between consecutive turns of the flight. The screw is rotatable within a barrel. A radially movable first member is disposed at a right angle to a longitudinal axis of the screw where the plasticated material has undergone partial melting. A reciprocatively movable second member is disposed within a bore through the shaft coaxial with the axis and includes a cam slidably engaged with an inner end of the first member such that the first member can be extended into the screw channel when the second member is moved in one direction and retracted from the channel when the second member is moved in another direction. At an upstream end of the second member there is provided a rotatable thrust transmitting coupling which allows rotation of the second member relative to a male threaded portion secured to the coupling and coaxial with the second member.