The invention relates to a filtering device for filtering a fluid, and in particular a liquefied plastic. The filtering device includes a control unit to control the position of a screen carrier by generating control signals such that the fluid pressure in a fluid inlet channel and/or in a fluid outlet channel remains within definable pressure ranges while a cavity is being filled.

The invention relates to a filtering device for filtering a fluid, and in particular a liquefied plastic. The filtering device includes a control unit to control the position of a screen carrier by generating control signals such that the fluid pressure in a fluid inlet channel and/or in a fluid outlet channel remains within definable pressure ranges while a cavity is being filled.

The invention relates to a screw extruder (29) having a housing (30) comprising an intake housing (4), a degassing housing (5), and at least one housing bore (21, 22) running in the interior of the degassing housing (5) and implementing at least one internal wall segment (25; 26; 27; 28) of the degassing housing (5) and serving for receiving at least one auger shaft (7), and wherein the at least one wall segment (25; 26; 27; 28) of the at least one housing bore (21, 22) comprises at least one partition wall (13, 33) protruding into the at least one housing bore (21, 22) in the region of the degassing housing (5), and wherein at least one filter element (8) is disposed in the interior of the degassing housing (5) and at least partially encompasses the at least one auger shaft (7) and bears on the partition wall (13) in regions for implementing at least two spatial pressure regions (11, 12) sealed off from each other.

A filtering device for removing dirt particles and contaminants from a plastic melt is disclosed. The filtering device includes a housing having a filter chamber, an inlet for feeding plastic melt, an outlet for channeling plastic melt out, and a dirt outlet for discharging dirt particles from the housing. The filtering device also includes a filter element arranged in the filter chamber to retain any dirt particles contained in the stream of melt, and a cleaning unit for cleaning the filter element of dirt particles retained by means of the filter element. The cleaning unit having a cleaning head with a scraper member for detaching dirt particles from the filter element. The scraper member is coupled to a servomechanism to press the scraper member onto the surface of the filter element. The servomechanism has at least one bellows cylinder including a foot section, a head section, a deformable bellows element, and a pressure chamber of variable volume.

An extruder is provided with: a screw rotationally driven about the axis by a first motor; a barrel having a screw hole into which the screw is inserted and a de-airing port configured to discharge air inside the screw hole; a filter configured such that a part thereof faces the de-airing port of the barrel; and a filter-driving mechanism configured to move the filter to shift the part of the filter facing the de-airing port.

A polymer melt candle filter having a support which comprises a hollow cylindrical body defined by a first end, a second end, and a cylinder wall having a first end portion and a second end portion. The first end portion includes a screw thread on its outside surface and optionally a hex fitting on its inside surface for receiving a hex wrench. The second end portion includes a plurality of holes in the cylinder wall. The area of the openings of the holes on the outside surface of the cylinder wall may be larger than the area of the openings of the corresponding holes on the inside surface of the cylinder wall. The shape of the openings of the holes on the outside surface may be non-circular. A polymer melt filter plate assembly which comprises (a) a support plate comprising a plurality of threaded holes; (b) at least one filter which is screwed into at least one of the threaded holes via the screw thread on the outside surface of the first end portion of the filter support; (c) a tie rod with (i) a first end extending through a hole in a cone insert and a cap located at the second end of the filter support, and (ii) a second end extending through a threaded hole in the support plate; and (d) a cross bar which is attached to the second end of the tie rod for holding the support plate inside a shaft of an apparatus for filtering a polymer melt.

A polymer melt candle filter having a support which comprises a hollow cylindrical body defined by a first end, a second end, and a cylinder wall having a first end portion and a second end portion. The first end portion includes a screw thread on its outside surface and optionally a hex fitting on its inside surface for receiving a hex wrench. The second end portion includes a plurality of holes in the cylinder wall. The area of the openings of the holes on the outside surface of the cylinder wall may be larger than the area of the openings of the corresponding holes on the inside surface of the cylinder wall. The shape of the openings of the holes on the outside surface may be non-circular. A polymer melt filter plate assembly which comprises (a) a support plate comprising a plurality of threaded holes; (b) at least one filter which is screwed into at least one of the threaded holes via the screw thread on the outside surface of the first end portion of the filter support; (c) a tie rod with (i) a first end extending through a hole in a cone insert and a cap located at the second end of the filter support, and (ii) a second end extending through a threaded hole in the support plate; and (d) a cross bar which is attached to the second end of the tie rod for holding the support plate inside a shaft of an apparatus for filtering a polymer melt.

A non-continuous rotation backwashing filter apparatus for a rubber/plastic extrusion/injection machine includes a machine frame having a rail, a rotary filter screen piston seat mounted to the rail and configured to carry a rotary filter screen piston covered with at least one layer of filter screen, and a die head. The rotary filter screen piston is telescopically pushed into a flow channel of the die head. The die head includes a flow channel pressure detector. In a normal state, the rotary filter screen piston does not rotate. When the flow channel pressure detector detects that the pressure of the flow channel rises to a predetermined value, the rotary filter screen piston begins to rotate for backwashing impurities on the filter screen. It can increase the filtering area of the filter screen, and the non-continuous rotation does not consume energy.

A non-continuous rotation backwashing filter apparatus for a rubber/plastic extrusion/injection machine includes a machine frame having a rail, a rotary filter screen piston seat mounted to the rail and configured to carry a rotary filter screen piston covered with at least one layer of filter screen, and a die head. The rotary filter screen piston is telescopically pushed into a flow channel of the die head. The die head includes a flow channel pressure detector. In a normal state, the rotary filter screen piston does not rotate. When the flow channel pressure detector detects that the pressure of the flow channel rises to a predetermined value, the rotary filter screen piston begins to rotate for backwashing impurities on the filter screen. It can increase the filtering area of the filter screen, and the non-continuous rotation does not consume energy.

A filter element for filtering a fluid comprises a first clamping ring with an outer ring; a first filter disk; a first inner support plate for supporting the first filter disk and which faces to the outside or to an inner flow channel; a second inner support plate provided with recesses; a second filter disk arranged adjacent the second inner support plate; and a second clamping ring which is connected to the first clamping ring by connecting elements. The filter disks and the inner support plates are arranged inside a housing which is formed by the clamping rings, by at least one outer ring and by outer support plates provided with recesses and covering the filter disks on the outside.