Abstract: A fractional lobe processor comprises a barrel with heating and cooling means having two parallel intersecting bores of equal diameter, wherein the centre distance between the two bores is lesser than the diameter of the bore; a shaft coupled with a plurality of screw elements to form a screw within each bore, wherein the screws are intermeshing and form at least three zones within the barrel, the zones comprising an intake zone comprising at least one deep flighted shovel element on each intermeshing screw for receiving a feed comprising an active substance and/or an excipient, a melt zone consisting of only fractional lobe elements for melting the active substance and/or an excipient to form a viscous mass or melt, and a discharge zone, wherein the melt zone is located before the discharge zone and after the intake zone; and wherein the melt zone has a plurality of fractional lobe elements on each shaft.

Abstract: A method and an extrusion device for producing a foamed body. A plastics melt is produced inside the casing of a first extruder. The plastics melt is conveyed to an outlet die of a second extruder. The conveyed plastics melt has a foaming agent and expands after being fed through the outlet die. Before the plastics melt is fed through the outlet die, variations in temperature between different radial positions over the cross-section of the plastics melt are reduced by an extruder screw device which has a number of screw spindles distributed around the periphery. The plastics melt which is thus thermally homogeneous is fed through the outlet die.

Abstract: Systems and methods are provided for fabrication of short-fiber composites. One embodiment is a method for forming a short-fiber composite. The method includes forming a bed of randomly oriented dry fibers on a base, drawing resin into the bed in response to pressure to form a mixture of randomly oriented fibers impregnated with thermoset resin, perturbing the mixture while preserving fiber length at the mixture and degassing the mixture, and extruding the mixture to form a preform.

Abstract: A coating apparatus having a rotatable drum with at least one moveable separating element arranged on an end side, and granular bodies can be transferred into the drum and/or out of the drum by a movement that leads to release. A separating element can be moved from a closed position into an open position by rotation about an axis of rotation. In the closed position, a subregion lies with its underside against an inner wall of the drum or has a small gap there. In the open position, the subregion on the underside is spaced apart from the inner wall of the drum and there is an opening there through which granular bodies can pass. On the end sides of the drum there are stop elements with which a drum of at least one further module is connectable in order to form a coating apparatus and/or a closure element.

Abstract: An element for a co-rotating twin screw processor, the element having a lead ‘L’ and at least one continuous flight helically formed thereon and, wherein the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’.

Abstract: The present invention relates to a process for preparing a comestible product comprising xylitol said method comprising: (a) subjecting a composition comprising xylitol in an amount ranging from about 60% to about 100% by weight to extrusion treatment inside an extrusion apparatus under conditions sufficient to form and maintain the xylitol in a slurry and (b) then shaping the extruded slurry and cooling the product to form a solid. The present invention additionally is directed to a product produced therefrom.

Abstract: Systems and methods for controlling the temperature of a solid-state screw extruder may include providing an extrusion screw that incorporates one or more screw shaft channels. The shaft channels may be configured to conduct a flow of a heat conducting medium along a length of the shaft. The shaft channels may be incorporated into an exterior surface or within the body of the screw shaft. The extruder may include extrusion screw elements in mechanical communication with the shaft. Each of the elements may further include one or more element channels also configured to conduct a flow of the medium. The shaft channels and the element channels may be disposed to permit a flow of the medium therebetween. The temperature of the extrusion screws and/or screw elements may be controlled by circulating the medium from a source, through the shaft and element channels, and back to the source.

Abstract: Disclosed is a method for manufacturing chewing gum, the method including feeding one or more gum ingredients including at least an elastomer into a continuous extruder including a plurality of screws, rotating screws and mixing the one or more ingredients via the rotating of the screws within the continuous extruder, forming a partial chewing gum base via the mixing of the one or more ingredients, creating a flow of the partial chewing gum base including the one or more ingredients through the continuous extruder towards a downstream extent of the plurality of screws via the rotating, and conveying the flow of the partial chewing gum base to a region of the continuous extruder that is proximate the downstream extent of the plurality of screws, wherein the flow includes a temperature of less than 90 degrees Celsius when the flow reaches the downstream extent of the plurality of screws. Some independent claims relate to a flow reaching two different temperatures that are within 20 degrees Celsius.

Abstract: The present invention relates to screw elements for multiscrew extruders with pairs of co-rotating and fully wiping screws, to the use of these screw elements in multiscrew extruders and to a method of generating screw elements according to the invention.

Abstract: In a two-shaft extruder, a pair of rotor shafts (1) is rotatably arranged such that the closer to the head end of the pair, the smaller the distance between the pair. The pair of rotor shafts (1) is respectively provided with screw blades (2) mounted on the head end side of the pair. The rotor shafts (1) are adapted such that one screw blade (2a) enters gaps of the other screw blade (2b). Drive devices (M) for rotationally driving the pair of rotor shafts (1) are mounted on the respective base ends of the pair. The extruder has a screw blade contact prevention mechanism (SS) which, when the pair of rotor shafts (1) is driven, prevents the pair from having a phase difference greater than a predetermined level.

Abstract: A twin screw extruder includes a barrel having a chamber, a discharge port, an extrusion molding die coupled to the discharge port of the barrel, axially extending first and second screw shafts, and a screw shaft support. The screw shaft support includes first and second spacer bearings disposed on the first and second screw shafts, and a first cross member including first and second loops slidably coupled to the first and second spacer bearings. A second cross member is spaced apart from the first cross member by a connection member, and also includes first and second loops slidably coupled to the first and second spacer bearings. The connection member is situated between the first spacer bearing and the second spacer bearing, and connected to the first cross member and the second cross member.

Abstract: Disclosed is an apparatus for the pretreatment and subsequent conveying or plastification of plastics, with a container with a mixing and/or comminution implement that is rotatable around an axis of rotation, wherein, in a side wall, an aperture is formed, through which the plastics material can be removed, a conveyor being provided, with a screw rotating in a housing. The invention is characterized in that the imaginary continuation of the longitudinal axis of the conveyor in a direction opposite to the direction of conveying passes the axis of rotation, there being, on the outflow side, an offset distance between the longitudinal axis and the radius that is parallel to the longitudinal axis, that the L/D ratio of the screw is ?7, and that the compressing format of the screw begins only from a distance (A) of more than 1.5 times the diameter (d) of the screw.

Abstract: The invention relates to a process and an apparatus for the preparation of a crosslinkable rubber mixture for vehicle tires, lines, drive belts and other industrial rubber articles, which can be carried out at least semicontinuously. The present invention is based on the discovery that the experiments known from the prior art to carry out the batchwise process usually used at least partly continuously have failed in particular because of the problem that the crosslinking agents have to be mixed rapidly and homogeneously with the base mixture, also referred to as rubber base mixture, without the mixture consisting of the base mixture and the crosslinking agents heating up too strongly. According to the invention, attention was therefore focussed on reliably mixing the base mixture homogeneously with the crosslinking agents and minimizing the mixing time. A first measure for achieving the desired aim consists in first mixing the crosslinking agents with one another before they are mixed with the base mixture.

Abstract: The invention relates to novel screw feed elements for multi-shaft screw feed machines having screw feed profiles rotating in the same direction in pairs and precisely abrading in pairs, to the use of the screw elements in multi-shaft screw feeding machines and to a method for extrusion of viscoelastic masses.

Abstract: A method for producing an aqueous electrode paste includes charging a powder made of an active material and a thickener and an aqueous solvent inside of a two-shaft kneader, and, using the two-shaft kneader, thickly kneading the powder and the aqueous solvent to generate a mixture; and charging a misty aqueous solvent having an average liquid droplet diameter of 1 ?m or more and an average particle diameter (D50) of the thickener or less inside of the two-shaft kneader by spraying, and using the two-shaft kneader, diluting the mixture with the charged aqueous solvent.

Abstract: What is described is a twin screw extruder having two extruder screws (10, 34), each extruder screw (10) having a cylindrical core (12) and at least one web (14) running helically over the periphery of the outer cylinder face of the core (12), the surface of the web (14) comprising a peripheral side (18) and two flanks (22, 24), and a channel (30) being formed between adjacent web windings. The flanks (22, 24) of the web (14) have a waved progression in the peripheral direction.

Abstract: A process of manufacturing a rubber compound is disclosed. The process comprises providing a multiple shaft extruder device; feeding the multiple shaft extruder device with at least one polymer raw material or with a mixture of at least two different polymer raw materials; feeding the multiple shaft extruder device with at least one further raw material; mixing the at least one polymer raw material or the mixture of the different polymer raw materials and the at least one further raw material in the multiple shaft extruder device to prepare a rubber compound; and extruding the rubber compound from the multiple shaft extruder device. A plurality of multiple shaft extruder devices may be used in parallel or in sequence.

Abstract: A mixing apparatus for manufacturing a rubber compound is disclosed. The mixing apparatus comprises a plurality of multiple shaft extruder devices, each comprising at least one inlet for receiving a plurality of materials to be fed into the extruder device and an outlet for discharging a mixed material extruded by the extruder device. The multiple shaft extruder devices are either arranged in such a way that operatively the extrudate of at least one of the plurality of multiple shaft extruder devices can be fed into the inlet of at least one other of plurality of multiple shaft extruder devices, or are arranged to operate in parallel in such a way that operatively the extrudates of the plurality of multiple shaft extruder devices can be fed together into the inlet of at least one further mixing device.

Abstract: The invention relates to novel screw feed elements for multi-shaft screw feed machines having screw feed profiles rotating in the same direction in pairs and precisely abrading in pairs, to the use of the screw elements in multi-shaft screw feeding machines and to a method for extrusion of viscoelastic masses.

Abstract: A treatment element to treat material in a multi-shaft worm machine has an outer contour with at least one outer contour portion, the associated evolute of which is a quantity of at least three points, each of the points lying outside the longitudinal axis and within the outer radius of the treatment element and two respective adjacent points having a spacing from one another, which is less than half the core radius. The treatment element ensures high flexibility during the adjustment of shear and/or extensional flows on the material to be treated.

Abstract: Improved single screw extruders systems (40) are provided including a single screw extruder (42, 92) as well as an upstream preconditioner (44). The extruders (42, 92) include a single, internal, elongated, helically flighted, axially rotatable screw assembly (52) having one or more improved screw sections (74, 74a, 76). The screw sections (74, 74a, 76) include specially configured flighting (86) wherein adjacent flighting portions (86a, 86b) have smoothly arcuate surfaces (88) extending between the respective flighting portion peripheries (90a, 90b). This flighting design provides smooth, substantially surge-free operation while increasing SME and cook values. The preferred preconditioner (44) has independently controlled mixing shafts (106, 108) allowing the shafts (106, 108) to be rotated at different rotational speeds and/or directions.

Abstract: An apparatus for wet granulating a powder material comprises:—a barrel having a granulation chamber and being provided with a first inlet (1) for receiving said powder material and for supplying it to said granulation chamber and with a second inlet (2) for receiving a granulating liquid and for supplying it to said granulation chamber, said granulation having an aperture (9) for discharge of granules from said barrel, and—a transporting means (S) for advancing said powder material toward the end of said granulation chamber while granulating it with the aid of said granulating liquid, said transporting means (S) comprising a first transport zone (4) at its rear end, an agglomeration zone (5) downstream from the first transport zone (4) and a second transport zone (8) at its front end, said first inlet (1) and said second inlet (2) being positioned above the first transport zone (4), wherein said aperture (9) has a shape tightly fitting the terminal portion of the transporting means (S) for directly dischargin

Abstract: A treatment element to treat material in a multi-shaft worm machine has an outer contour with at least one outer contour portion, the associated evolute of which is a quantity of at least three points, each of the points lying outside the longitudinal axis and within the outer radius of the treatment element and two respective adjacent points having a spacing from one another, which is less than half the core radius. The treatment element ensures high flexibility during the adjustment of shear and/or extensional flows on the material to be treated.

Abstract: An extruder screw segment has opposed end faces disposed at a non-orthogonal angle with respect to a rotation axis of the body.

Abstract: In an extruder wherein the slip-on elements (1) have a cross-sectional profile comprising circular arcs corresponding to the maximum slip-on element diameter, the slip-on element core diameter and the center distance of the slip-on elements (1), the slip-on element (1) has no shaft-to-hub connection in the area of the circular arc corresponding to the slip-on element core diameter and/or it is provided at its ends with reinforcement segments (13, 14).

Abstract: A mixing device for synthetic leather to joint with a solid powder material includes a material mixing unit and a stirring and conveying unit. The material mixing unit includes a mixing body and two feeders. The mixing body is connected with the two feeders and has a mixing chamber therein which is intercommunicated with the two feeders. The stirring and conveying unit is connected with the material mixing unit and has a stirring and conveying chamber therein which is intercommunicated with a solid material container and the mixing chamber. Thereby, a solid powder material, a first material and a second material are respectively disposed in the solid material container and the feeders, and then guided into the mixing chamber to be well mixed for forming a mixture. The mixture is manufactured to form synthetic leather containing the solid powder material.

Abstract: One object of the present invention is to provide a kneader which can diminish wear of screws and a barrel while preventing the manufacturing process for the screws and barrel from becoming complicated. In this kneader, a pair of screws are rotated about respective axes thereof to knead a material to be kneaded which is introduced into a kneading space formed within a barrel. Each screw has such a shape generating deflection in a predetermined direction perpendicular to an arranged direction of the axes of the pair of screws during kneading of the material to be kneaded, and the kneading space has a shape such that a pair of accommodating spaces which accommodate each of the screws respectively are connected together so as to overlap each other partially in the radial direction, each accommodating space being formed in such a manner that the diameter thereof in the predetermined direction in which there occurs deflection of each screw is larger than in any other direction.

Abstract: A processing installation for devolatilization of polymer melts comprises a first extruder and a second extruder arranged downstream thereof in a direction of conveyance. The first extruder comprises several rotatably drivable first shafts which are provided with first treatment members and several devolatilization zones with associated devolatilization ports. Correspondingly, the second extruder comprises several rotatably drivable second shafts which are provided with second treatment members and several second devolatilization zones with associated devolatilization ports. The first treatment members have an external diameter which is smaller than or equal to that of the second treatment members. A devolatilization unit is arranged in a transfer zone which interconnects the extruders. The devolatilization unit comprises a perforated plate and a clearance arranged downstream in the direction of conveyance.

Abstract: An improved multiple-screw extruder, in particular a twin-screw extruder comprises a housing. Several housing bores are located in at least one section within the housing. The housing bores overlap at least along a partial axial length of the housing. One extruder screw is arranged in each of the several housing bores. At least two motors are provided for the at least two extruder screws. A synchronizing and torsion transmitting device, by means of which both cooperating extruder screws can be synchronized, is provided on both the inlet side and the discharge side.

Abstract: The invention provides a golf ball material which is a resin mixture composed of (a) an olefin-unsaturated carboxylic acid copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 120,000 to 200,000 and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of from 4.3 to 6.6 or a metal neutralization product thereof, (b) an olefin-unsaturated carboxylic acid copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 120,000 to 200,000 and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of from 6.8 to 9.

Abstract: There is provided a multi-screw extruder for reclaiming foam made of cross-linked polymer material into reusable material by causing the foam to pass through a kneading zone, wherein the kneading zone is divided into at least preceding and subsequent two kneading zones and a temperature equalizing transfer zone for equalizing temperature of the material passing through the zone is provided between the preceding kneading zone and the subsequent kneading zone.

Abstract: A viscoelastic material is extruded by kneading-and-conveying screws of different respective diameters positioned coaxially and telescopingly. A flight trough of a larger-diameter screw has radial orifices allowing a first space swept by the flight of the larger-diameter screw to communicate with a second space swept by a flight of a smaller-diameter screw. A fixed cylindrical tube arranged coaxially with the screws is disposed radially between the first and second spaces within the region in which the screws telescope. The tube has radial apertures therethrough to conduct material from the orifices to the second space. The first space is closed off at an axial end thereof by a wall where foreign substances accumulate that do not pass through the orifices. A passage through the wall can be opened to remove the accumulated substances without interrupting the extrusion operation.

Abstract: There is provided a melting kneading devolatilizing extruder in which the surface renewability of a molten raw material is improved. The melting kneading devolatilizing extruder of the invention includes at least one surface renewable screw segment each including a plurality of discs that are arrayed such that a phase angle E, which is a deviation angle between the discs around an axis of a screw, is 0°<E<90° within a surface renewal region, and the surface renewable screw segment includes a void portion between the discs so that the discs are arranged at intervals in a direction of the axis of the screw.

Abstract: A digital video recording apparatus and an editing method for recorded broadcast programs are disclosed. In accordance with the disclosed apparatus and method, information of recorded broadcast programs is extracted from a broadcast stream which includes the broadcast programs. The extracted information is displayed on a display in the form of a program record list. Accordingly, the user can easily edit recorded broadcast programs by simply editing the program record list.

Abstract: A process for producing a cycloolefin resin composition comprising a cycloolefin resin and an additive by using a twin-screw extruder is provided, in which loss of the additive caused by volatilization through a vent during kneading is reduced and kneading of resin material with the additive can be sufficiently carried out. When the cycloolefin resin and the additive are kneaded by using a vented twin-screw extruder (10) to produce the cycloolefin resin composition containing the additive, an additive introduction opening (3) is disposed downstream of a vent (2) located nearest to a discharge opening (13) of the twin-screw extruder, and the additive is charged through the additive introduction opening located at a distance from the discharge opening of the twin-screw extruder in the range between longer than 10D and not longer than 30D.

Abstract: An extruder for viscous masses, and including an extruder screw and a positive-displacement gear pump disposed downstream of the extruder screw as viewed in the conveying direction. The positive-displacement gear pump has at least one conveying gear and at least one positive-displacement gear. The axis of the conveying gear is disposed essentially at right angles to the axis of the extruder screw, and the axis of the positive-displacement gear is disposed essentially in the same direction as the axis of the extruder screw.

Abstract: Fluoroplastics containing fluorocarbon resins and silicones are prepared by first mixing a fluorocarbon resin with a compatibilizer, then adding a curable organopolysiloxane with a radical initiator, and vulcanizing the organopolysiloxane in the mixture. The fluoroplastics can be processed by various techniques, such as extrusion, vacuum forming, injection molding, blow molding or compression molding, to fabricate plastic parts. The resulting fabricated parts can be re-processed (recycled) with little or no degradation of mechanical properties.

Abstract: A conveying screw member for a plastic granule cutting and transporting mechanism includes a plastic granule collector, a heating conduit, a conveying screw, a plastic granule molding structure and a power transmission device. The plastic granule collector is a hollow cylinder which has an outlet being positioned thereon. The heating conduit is a longitudinal hollow tube which has a round hole being respectively positioned at both ends. The conveying screw member which has the conveying screw being set thereon, and the reversing screws and two supporting bases being respectively set at both ends is installed in the heating conduit. The plastic granule molding structure is equipped near the edge of the end of the heating conduit. The power transmission device is installed near the plastic granule collector and attached to the supporting base of one end of the conveying screw member.

Abstract: A machine for the mixing and extrusion of rubber-based and silicone-based plastic materials and method thereof is disclosed, comprising a dump extruder with conical converging twin screws (10) arranged in a batching chamber (12) in which the outlet of the dump extruder is temporarily closed by a removable blind flange (11), the batching chamber also acting as a compounding chamber.

Abstract: The present invention relates to a powder fabricating apparatus. It is an object of the present invention to provide the powder fabricating apparatus, which is capable of obtaining metal powder in a rapid and continuous fashion, various kinds of oxide, or alloy powder. The powder fabricating apparatus for achieving the object of the present invention comprises a barrel wherein an inlet and an outlet are formed at both opposite ends thereof, respectively; a screw which is rotationally mounted in the barrel and by which reactant supplied from the inlet moves toward the outlet; a driving portion for causing a relative rotational motion between the screw and the barrel; reaction control means for controlling reaction conditions of the reactant which moves in the barrel; and a controller for controlling the driving portion and the reaction control means.

Abstract: The invention concerns an extruder for producing molted plastic materials from plastic granules available on the market, by heating and mixing granules, with heated single- or double-screw extruders, and for carrying out polycondensation or polymerization using part of a multiple-screw extruder and by means of vacuum chambers for removing the constituents of low molecular weight and/or foaming agents or the like, for obtaining larger molecules and hence a higher viscosity, and for increasing the mechanical strength of plastic materials produced from said molten material. The invention aims at designing said extruder such that the molten material can be processed in thin layers enabling exposure of large surfaces in contact with the vacuum, and hence a molten plastic material ensuring desired levels of degassing and polymerization using simple means.

Abstract: An extruder for viscous masses, and including an extruder screw and a positive-displacement gear pump disposed downstream of the extruder screw as viewed in the conveying direction. The positive-displacement gear pump has at least one conveying gear and at least one positive-displacement gear. The axis of the conveying gear is disposed essentially at right angles to the axis of the extruder screw, and the axis of the positive-displacement gear is disposed essentially in the same direction as the axis of the extruder screw.

Abstract: In the field of continuous mixer apparatus for commingling particulate thermoplastic materials, employing at least one main rotor with a helical profile body configuration, an improved profile for the peripheral threads is provided. It presents a first upstream feed flight having a plurality of Lowenherz profile outer threads and second downstream feed flight having a plurality of screw-type outer threads, both being adjacent and integral with the periphery of the main rotor.

Abstract: In a conical twin-screw extruder in which two rotor shafts having flights on the outer peripheral surfaces thereof and being adjacent to each other in the lateral direction are accommodated in a barrel having a raw material supply port on one side and a raw material discharge port on the other side, and the distance between the rotor shafts and the outside diameters of the flights thereof are gradually reduced from the supply port side to the discharge port side, characteristically, the barrel is provided with a water-removing port for removing water contained in a raw material supplied through the raw material supply port, out of the barrel. The extruder can be applied to raw materials various shapes, sizes, and properties.

Abstract: The invention provides an improved mixer section for a screw for a molding machine. The improved mixer section includes at least one conveying flight and at least one spill flight intersecting with the conveying flight. At least one notch is formed in the conveying flight to enable mixing between adjacent flow channels. The spill flight terminates near the output of the mixer to create a trap zone for any unmelts that reach that area of the mixer.

Abstract: An extruder/gear pump assembly is provided having an extruder screw connected to the gear pump. The relative speed of the extruder screw and the gear pump are adjustable by the use of a shaft housed in a cavity of the extruder screw.

Abstract: A material processing plant comprises a first screw-type extruding machine (1) and a second screw-type extruding machine (2) which is disposed downstream thereof. Between the two screw-type extruding machines (1, 2), provision is made for a delivery zone (28) where a delivery orifice is provided, extending radially of the axes (12a, 13a) of the casing bores (12, 13) of the first screw-type extruding machine (1) and being directed towards the second screw-type extruding machine (2). The at least one casing bore (12, 13) of the first screw-type extruding machine (1) is lockable in the direction of its axis (12a, 13a) by means of a sealing element.

Abstract: A drive apparatus for an extruder with at least two co-rotating extruder screws having driveshafts includes a housing and a drive motor which is received in the housing and including a stator and a rotor. The rotor is operatively connected to driveshafts of the extruder screws and has arranged thereon a toothed surface in direct engagement with complementary toothed surfaces of at least two of the driveshafts of the extruder screws.

Abstract: The invention relates to a method for continually producing a suspension of cellulose in an aqueous tertiary amine oxide. The method includes (a) mixing cellulose and an amine oxide-free aqueous phase to form a cellulose suspension in a mass ratio in the range of 1:3 to 1:40, (b) dehydrating the cellulose suspension, wherein the dehydrated cellulose suspension has a cellulose content in the range of 20 to 80 percent-by-mass; (c) mixing the cellulose suspension with an aqueous amine oxide while the cellulose suspension is falling through a vertical fall zone to obtain an aqueous amine oxide-cellulose suspension with an amine oxide content in the range of 70 to 80 percent-by-mass; and (d) conveying the aqueous amine oxide-cellulose suspension through a horizontal shear zone. The invention also relates to a device for carrying out this method.

Abstract: An extrusion molding apparatus comprises a shaping die for producing a ceramic molded product, and a screw extruder having built therein an extruding screw (40) for mixing while leading a ceramic material forward. The extruding screw (40) includes a pressing screw portion (410) having a first lead (411) and a dispersing screw portion (420) having a second lead (421) adjacent to a forward end (412) of the pressing screw portion (410). The second lead (421) is formed in such a manner that the rear ends of all the second lead surfaces (426) at the rear end (422) of the dispersing screw portion (420) and the forward end of the first lead surface (416) at the forward end (412) of the pressing screw portion (410) are displaced from each other.