Abstract: A liquid ring vacuum pump for degassing molten plastic has an inlet where gases are drawn in and an outlet through which gases are blown out. A closed circulation path for the compression fluid holds a replaceable filter insert for filtering coarse contaminants out of the compression liquid, a precondensation unit upstream of the pump inlet for filtering fine contaminants out of the compression liquid, and only one continuously operating fine or ultrafine filter in the closed circulation path. The closed circulation path is closed even when the fine filter or ultrafine filter is replaced. A controller connected to the continuously operating filter directs replacement of the filter element as a function of degree of contamination, filtering time, pressure conditions, or flow velocity conditions at the filter.

Abstract: A valve has a housing formed with a central chamber centered on and extending along a main axis, an inlet passage and an outlet passage having mouths in the chamber spaced angularly from and confronting each other, and a secondary passage offset from the inlet and outlet passages and centered on an axis offset from a center of one of the mouths by more than 90°. A valve pin fitted in the chamber is formed with a secantally throughgoing flow passage centered on a flow-passage axis generally parallel to but offset from a diameter of the pin. A filter is provided in the flow passage, the secondary passage being sufficiently large that, when the pin is pivoted to align the flow passage with the secondary passage, the filter can be removed from the flow passage through the secondary passage.

Abstract: A viscometer for molten plastic has a housing having first and second relatively displaceable parts with generally complementary and substantially planar faces. The first part is formed with a throughgoing melt passage adapted for connection in a flow system of the molten plastic. A hinge interconnects the parts. An outgoing conduit extends from the melt to a pump intake and from a pump output to an opening on the face of the first housing part. A plurality of sensors on one of the parts are connected to respective openings on the face of the one part. A return conduit extends from another opening on the face of the first housing part offset from the opening of the outgoing line. An exchangeable metal foil formed with a slot into which all of the openings open is engaged tightly between the two faces.

Abstract: A melt filter for cleaning a plastic melt issuing from an extruder has a wheel rotatable about an axis and having an outer rim and a plurality of spokes forming an annular array of axially open spaces, a pair of housing plates axially sandwiching and completely covering the wheel and forming offset from the axis a melt passage extending axially through the wheel at the spaces, and removable filter elements braced axially against the wheel at the spaces between the spokes and angularly movable with the wheel with the melt flowing through the filter elements when same are aligned with the passage. One of the plates being formed with an edge cutout. A part on the one housing plate that can cover and close the cutout during normal operation of the melt filter can open and uncover the cutout for changing the filter element aligned axially with the cutout.

Abstract: A melt filter, for the purification of plastic melts, particularly dispensed from extruders, comprises a housing (1) with a melt channel (10), connecting a melt inlet (7) to a melt outlet (9), with a sieve disc (5), which may be rotated by a motorized ratchet drive provided in the melt channel (10), comprising recesses separated by ridges in a circular track for housing exchangeable filter elements and the housing (1) has a filter element changing station (13). The aim of the invention is that the above shall be designed such that large amounts of melt for filtering can be filtered in a cost-effective energy saving and space saving manner. The above is achieved by means of the housing comprising at least two melt inlets (7, 8) connected to the melt outlet (9) by at least two melt channels (10, 11) and in each melt channel (10, 11) a sieve disc (5, 6) driven on rotation by a motorized ratchet drive is provided and each sieve disc (5, 6) is provided with a filter element exchange station (13, 15).

Abstract: A melt filter, for the purification of plastic melts, particularly dispensed from extruders, comprises a housing (1) with a melt channel (10), connecting a melt inlet (7) to a melt outlet (9), with a sieve disc (5), which may be rotated by a motorised ratchet drive provided in the melt channel (10), comprising recesses separated by ridges in a circular track for housing exchangeable filter elements and the housing (1) has a filter element changing station (13). The aim of ethinvetion is that the above shall be designed such that large amounts of melt for filtering can be filtered in a cost-effective energy saving and space saving manner. The above is achieved by means of the housing comprising at least two melt inlets (7, 8) connected to the melt outlet (9) by at least two melt channels (10, 11) and in each melt channel (10, 11) a sieve disc (5, 6) driven on rotation by a motorised ratchet drive is provided and each sieve disc (5, 6) is provided with a filter element exchange station (13, 15).

Abstract: The invention relates to a device (1) for providing a melt, in particular a plastic melt. Said device (1) comprises a feed unit (2) for material components, at least one purification unit (4) for the flowing melt, in particular a rotatable screening disc (5), and at least one sensor unit (17; 18; 19; 20; 21) for detecting one or more process parameters. The operation of the purification unit (4) can be influenced with the aid of said sensor unit, based on the filter-specific process data. The inventive device is configured in such a way that at least the type and dosage of the process materials that are supplied via the feed unit (2) and/or the processing parameters of said process materials can be controlled using the detected (17; 18; 19; 20; 21) process parameters and/or the filter-specific process data.

Abstract: A device for cleaning melt filters which are intended for filtering melts, particularly plastic material melts in extruders, and which include at least one moveable sieve disc with one or more exchangeable sieve inserts, wherein at least one sieve insert is moveable into a flow of cleaning medium within the device in such a way that the sieve insert is located above or below an inlet opening of a cleaning duct. The sieve insert is arranged in the sieve disc at a distance from the surface of the sieve disc which faces the inlet opening.

Abstract: A device for cleaning melt filters which are intended for filtering melts, particularly plastic material melts in extruders, and which include at least one moveable sieve disc with one or more exchangeable sieve inserts, wherein at least one sieve insert is moveable into a flow of cleaning medium within the device in such a way that the sieve insert is located above or below an inlet opening of a cleaning duct. The sieve insert is arranged in the sieve disc at a distance from the surface of the sieve disc which faces the inlet opening.

Abstract: A multipath valve for distributing and/or dividing at least one flow of polymer melt during the manufacture and processing thereof, wherein melt flows through all internal chambers of the valve during all conditions of operation. At least one rotary disc is rotatably mounted on an axle bolt between a front plate and a rear plate which are each provided with openings serving as inlets and outlets for the polymer melt. The rotary disc is provided with circular segment-shaped ducts having a width and end radii corresponding to an inner width of the openings, wherein the ducts have center lines which are located on a reference circle extending through the centers of the openings, and wherein the positions of the ducts are adjustable in accordance with a desired flow direction of the polymer melt.

Abstract: A polymer melt filtering device comprising a housing with an inflow (3) and an outflow (4) for the polymer melt, in addition to a slider (5) which can be sealingly displaced therebetween, perpendicular to said inflow and outflow. The slider (5) consists of filtering layers (7) which are supported in cavities (8) and which can be selectively placed in between the inflow and outflow. The housing is comprised of two parts (1, 2) that are arranged in such a way that their front surfaces face towards each other. The inventive device is characterised in that one of the parts of the housing (1, 2) is floatingly mounted; in that the parts of the housing are reinforced in the middle area of the housing by beads (11), whereby the edges thereof (pressure surfaces 12) are slanted towards the outside or are conical; and in that the parts of the housing (1, 2) are maintained by clamping plates (12-15) which can be placed against each and which encompass and clamp the beads (11).

Abstract: A shot piston device for molten plastic material with a force-operated piston guided in a cylinder provided with an inlet and an outlet, wherein valve arrangements ensure that the cylinder is filled during the return stroke of the piston and the cylinder content is discharged during the work stroke of the piston. The piston is fixedly connected by a drive bolt to a differential piston arranged upstream or in front of the piston. At least in its rearward extreme position, the differential piston covers and closes the outlet arranged in the corresponding differential cylinder. The circumference of the piston has at least one groove located underneath the inlet and extending from the end face of the piston facing the differential piston. The length of the groove is shorter than the length of the piston. A closing ring is arranged so as to be axially slidable on a cylindrical portion of the drive bolt arranged in front of the end face of the piston facing the differential piston.

Abstract: The seals between the plates and a swingable or slidable sieve insert carrier can be hollow to receive a substance having a greater coefficient of thermal expansion than the metal shell of the seal so that the pressing force is generated by expansion of the substance.

Abstract: A filter for a synthetic resin melt has a housing formed from two blocks through which a melt channel for the passage of the plastics melt passes. A screen plate is rotatably mounted to intrude between the blocks and a plurality of recesses are distributed in a circular pattern around the periphery of the screen plate so that rotation can bring two of the recesses in to line with the channel. A plurality of filter elements are accommodated, one each in each recess, so that the plastic melt must pass through the filters in the recesses in line with the channel. To support the filter elements against melt pressure a stationary perforated plate is located in the channel immediately adjacent and downstream of the screen plate. By rotating the screen plate exhausted filter elements can be readily replaced. The filter elements are made of woven wire cloth and may be dished to prevent distortion of the mesh.

Abstract: An inlet plate is normally connected to an extruder and formed with an inlet port for supplying a molten synthetic resin under pressure to the port and an outlet plate is normally connected to or part of a mold and is formed with an outlet port in line with and confronting the inlet port for receiving the molten synthetic resin. A movable filter support engageable snugly between the plates at the ports thereof is formed with at least two laterally offset cavities each having an inlet side against the inlet plate and an outlet side against the outlet plate. This support element can be displaced between at least two respective positions in each of which one of the cavities is aligned between the ports for flow through the one cavity therebetween. A respective filter unit in each of the cavities has a plurality of separate cells each having an outside exposed to flow from one of the ports and an inside exposed to the other of the ports.

Abstract: A filter assembly used in combination with an extruder producing a stream of pressurized molten plastic has an inlet plate formed with a Y-shaped inlet passage having a substantially circular-section upstream end adapted to receive the stream of pressurized molten plastic from the extruder. The inlet passage branches downstream of its upstream end and has a pair of downstream ends opening at substantially circular downstream ports. An outlet plate fixed immediately downstream of the inlet plate is formed with a Y-shaped outlet passage having a substantially circular-section downstream end. The outlet passage is branched symmetrically to the inlet passage upstream of its downstream end and has a pair of upstream ends opening at substantially circular upstream ports aligned with the downstream ports. A rotatable filter disk engaged between the plates is formed with a circularly annular array of substantially circular-section throughgoing holes each defining a respective substantially circular seat.

Abstract: A filter assembly used in combination with an extruder producing a stream of pressurized molten plastic has an inlet plate formed with a Y-shaped inlet passage having a substantially circular-section upstream end adapted to receive the stream of pressurized molten plastic from the extruder, The inlet passage branches downstream of its upstream end and has a pair of downstream ends opening at substantially circular downstream ports. An outlet plate fixed immediately downstream of the inlet plate is formed with a Y-shaped outlet passage having a substantially circular-section downstream end, The outlet passage is branched symmetrically to the inlet passage upstream of its downstream end and has a pair of upstream ends opening at substantially circular upstream ports aligned with the downstream ports.

Abstract: A sieve arrangement for cleaning synthetic plastic melts of a high pressure press has a housing having a throughflow opening which is arranged to form a part of a flow passage of a high pressure press, a disc provided with a plurality of perforations and movable in the housing so that at least one of the perforations is always in the region of the throughflow opening and at least one of the perforations is always outside the housing, a plurality of sieve discs arranged inside the perforations, a blockable spraying passage provided at the side of the throughflow opening which is located behind the disc as considered in a flow direction, a slot-shaped spraying nozzle associated with the perforation located away outside the throughflow opening and inside the housing so that the spraying passage opens into the spraying nozzle, an outlet passage provided in the housing at a side of the disc which is opposite to the spraying nozzle.

Abstract: A screening device for a melt of plastic material includes a housing provided with a throughflow boring forming a part of a high pressure plastic press. A screen plate is movable transversely across the boring and includes a series of screening openings arranged at the level of the throughflow boring and being separated one from each other by an narrow web. To minimize the formation of pressure gradients in the throughflow boring when a new screening opening is entering the boring, each web has at its interface with the housing a narrow overflow slot which sets up a gradual connection for an inflow current of the melt during the entry of a new evacuated opening into the region of the throughflow boring.