Sealing plate for a spinnerette assembly

Abstract: A device for changing the filament count from a spinnerette assembly includes a sealing plate (10) positioned upstream from said spinnerette assembly to prevent the passage of the material being spun into one or more particular spinnerette bores (5a).

Description: The invention concerns a spinnerette assembly comprising: a spinnerette plate having a number of bores extending from an upstream side to a downstream side of said spinnerette plate, and means arranged adjacent to the upstream side of said spinnerette plate and adapted to deliver material to be spun to said spinnerette plate, said means comprising a sealing plate having flow channels formed therein which are fewer in number than said bores of said spinnerette plate, each of said flow channels corresponding in position to and communicating with a respective bore in said spinnerette plate. The invention relates generally to melt spinning filaments or fibers using a spinnerette. More particularly, this invention relates to an apparatus for changing the number of filaments being spun from a single spinnerette. Spinnerette assemblies for spinning synthetic filaments or fibers typically include an inlet block having an inlet port through which the material to be spun is introduced into the spinnerette assembly and a chamber containing filtering material, a distribution plate, a distribution cavity, a metering plate and a spinnerette plate. The metering plate includes a number of apertures having a compound shape, consisting of a capillary and a counterbore. The spinnerette plate normally includes a corresponding number of bores having a compound shape consisting of a counterbore or capillary and a jet or spinning orifice. A typical spinnerette assembly is disclosed in U.S. 3,095,607. Other spinnerette assemblies are described in U.S. 3,028,627, U.S. 2,883,261, U.S. 3,225,383, U.S. 3,289,249, U.S. 3,601,846, U.S. 3,659,988, and U.S. 4,738,607. It is sometimes desirable to change the number of filaments being spun from a single spinnerette. Reasons for altering the filament count may include product variations, keeping the tow denier constant while changing the filament denier, changing quenching characteristics and maintaining spinning speed at higher denier per filament where extruder capacity is limited. The traditional method for changing filament count is to individually plug spinnerette capillaries using a soft metal bar of approximately the same diameter as the counterbore. This method is time consuming, risks damage to the spinnerette and does not insure a leak-free seal. A spinnerette assembly comprising the features of the pre-characterizing part of claim 1, and a method for spinning a number of different filament counts from a single spinnerette plate is described in U.S. 3,336,633. The spinnerette assembly according to the U.S. 3,336,633 employs metering plates having a number of apertures lower than the number of orifices in the spinnerette plate. Since the compound shape of the apertures in the metering plate are normally precision drilled to provide a desired pressure drop, the metering plates are relatively expensive to produce and maintaining a stockpile of metering plates to provide a variety of fiber counts may be cost-prohibitive. It is the object of the present invention to provide a simple and inexpensive apparatus and a method for changing the filament count from a spinnerette plate. To achieve this object, the spinnerette assembly according to the invention is characterized in that the flow channels in said sealing plate have a non-compound cylindrical shape. The sealing plate may be sandwiched between a metering plate and the spinnerette plate in which case the sealing plate changes the filament count from the spinnerette by blocking the metering aperture and preventing the material being spun from passing to the spinnerette orifice corresponding to the blocked metering aperture. Preferred embodiments of the spinnerette assembly according to the invention are specified in claims 2 to 5. The sealing plate provides a good seal of one or more capillaries of the spinnerette plate. A subject of the invention is also a method of changing the filament count from a spinnerette plate having a plurality of bores, the method comprising: blocking at least one bore of said spinnerette plate by installing a sealing plate adjacent the upstream side of said spinnerette plate, the sealing plate having flow channels formed therein, each flow channel corresponding in position to a bore in the spinnerette plate, the number of flow channels being less than the number of bores in the spinnerette plate (see U.S. 3,336,633). The method according to the invention is characterized by employing a sealing plate which has non-compound cylindrical flow channels. Preferably, said sealing plate is installed intermediate said spinnerette plate and a metering plate having a plurality of apertures corresponding in number and location to the number and location of the bores in the spinnerette plate. The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. This invention can, however, be embodied in many different forms and the invention should not be construed as being limited to the specific embodiments set forth herein. Rather, the applicant provides these embodiments so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. Fig. 1 is an exploded perspective view of a spinnerette assembly in accordance with the invention; and Fig. 2 is a partial axial longitudinal section of an alternative embodiment of a spinnerette assembly in accordance with the invention. Referring now to Fig. 1, a spinnerette assembly includes an inlet block 3 and a spinnerette plate 4. The spinnerette plate 4 includes a number of bores 5. The bores 5 may be of compound shape, having a relatively large counterbore 6 at the upstream side and a relatively small spinning orifice 7 through which the material being spun exits the spinnerette plate 4. Between the inlet block 3 and the spinnerette plate 4 is sealing plate 10. Sealing plate 10 includes one or more flow channels 11, each of which is positioned to correspond with one of the bores 5 in the spinnerette plate 4. The sealing plate 10 contains at least one less flow channel 11 than the number of bores 5 in the spinnerette plate 4. Thus, the sealing plate 10, will block at least one bore 5 of the spinnerette plate 4, preventing the passage of the material being spun, thereby changing the filament count from the spinnerette. As seen in FIG. 1, there is no flow channel corresponding to bore 5a in spinnerette plate 4, thereby changing the filament count from 5 to 4 from the illustrated spinnerette. Sealing plate 10 can be manufactured from any suitable material, such as, for example, mild steel, stainless steel, brass or aluminum. Sealing plate 10 and flow channels can be formed by any suitable manufacturing technique such as, for example, die cutting, drilling, punching, stamping, etching, machining, or molding. Any suitable means may be employed to align the various components of the spinnerette assembly in precise registry with each other and to maintain the assembled spinnerette assembly in a tight fitting relationship. For example, apertures (not shown) may be formed in each component which, in the assembled spinnerette assembly, provide thruways accommodating terminally threaded aligning bolts or rods (not shown) which receive locking nuts (not shown). The overall dimensions of the spinnerette plate 4 and the sealing plate 10 may vary considerably. In general, the spinnerette plate and the sealing plate will have the same or substantially the same planar dimensions. While in some instances spinnerette plates may be as large as a few feet in length, typically, the planar dimensions range from about 25 mm to 305 mm (1.0 to about 12 inches) in length and about 25 mm to 203 mm (1.0 to about 8.0 inches) in width. The thickness of the spinnerette and sealing plates may be the same or different. Preferably, however, the sealing plate 10 will be substantially thinner than the spinnerette plate 4. Typically, the thickness of the spinnerette plate 4 may be between about 6,4 mm to about 38 mm (.25 to about 1.5 inches), while the thickness of the sealing plate 10 will preferably be between about 0,12 mm to about 2,5 mm (0.005 to about 0.1 inches). The location or pattern of the bores 5 in spinnerette plate 4 and the corresponding flow channels 11 in sealing plate 10 may also vary considerably. Additionally, the diameter of the bores 5 and the flow channels may vary, ranging, for example, between about 2,5 mm to about 7,6 mm (0.1 to about 0.3 inches) in diameter. Preferably, the diameter of the flow channel 11 corresponds to the diameter of the counterbore 6 at the upstream side of spinnerette plate 4. Referring now to FIG. 2, in another embodiment of the invention the spinnerette assembly includes an inlet block 23, a metering plate 28, and a spinnerette plate 24. Sealing plate 30 is located between the metering plate 28 and the spinnerette plate 24. The metering plate 28 has a number of apertures 29 bored therein. The number and location of the apertures 29 in the metering plate 28 correspond to the number and location of bores 25 in the spinnerette plate 24. The bores 25 may be of compound shape, having a relatively large counterbore 26 at the upstream side and a relatively small spinning orifice 27 through which the material being spun exits the spinnerette plate 24. The sealing plate 30 includes a number of flow channels 31 formed therein. The flow channels 31 are positioned to correspond with the apertures 29 in the metering plate 28 and the bores 25 in the spinnerette plate 24. The sealing plate 30 contains at least one less flow channel 31 than the number of apertures 29 and bores 25. Thus, the sealing plate 30 will prevent the passage of the material being spun from aperture 29a to bore 25a, thereby reducing the filament count from the spinnerette. It should be understood that the sealing plate may be positioned adjacent to the upstream face of the metering plate, or at any other position in the spinnerette assembly provided that the sealing plate prevents the passage of the material to be spun into one or more particular spinnerette bores, thereby changing the filament count. As will be appreciated by those skilled in the art, the cost of manufacturing a number of sealing plates for use in accordance with the present invention is significantly less than the cost of producing a corresponding number of metering plates or spinnerette plates to effect various changes in filament count. This is due primarily to the ease and simplicity of forming the flow channels in the sealing plate of the invention compared to the difficulties encountered in forming the compound shape of the precision drilled apertures in metering plates and spinnerette plates.

Claims: A spinnerette assembly comprising: a spinnerette plate (4; 24) having a number of bores (5; 25) extending from an upstream side to a downstream side of said spinnerette plate (4; 24), and means (3, 10; 28, 30) arranged adjacent to the upstream side of said spinnerette plate (4; 24) and adapted to deliver material to be spun to said spinnerette plate (4; 24), said means (3, 10; 28, 30) comprising a sealing plate (10; 30) having flow channels (11; 31) formed therein which are fewer in number than said bores (5; 25) of said spinnerette plate (4; 24), each of said flow channels (11; 31) corresponding in position to and communicating with a respective bore (15; 25) in said spinnerette plate (4; 24), characterized in that the flow channels (11; 31) in said sealing plate (10; 30) have a non-compound cylindrical shape. A spinnerette assembly according to claim 1, characterized in that said means (28, 30) for delivering material to be spun to said spinnerette plate comprise a metering plate (28) arranged adjacent to said sealing plate (30) and having a number of apertures (29) corresponding in number and location to the bores (25) in said spinnerette plate (24). A spinnerette assembly according to claim 2, characterized in that said sealing plate is arranged intermediate the metering plate (28) and the spinnerette plate (24). A spinnerette assembly according to one of the preceding claims, characterized in that said bores (5; 25) of said spinnerette plate (4; 24) have at least one tapered section, that said sealing plate (10; 30) is arranged adjacent to the upstream side of said spinnerette plate (4; 24), and in that the diameter of said flow channels (11, 31) corresponds to the diameter of said bores (5; 25) at the interface of said spinnerette plate (4; 24) and said sealing plate (10; 30). A spinnerette assembly according to one of the preceding claims, characterized in that said sealing plate (10; 30) is formed from a material selected from: mild steel, stainless steel, brass or aluminium. A method of changing the filament count from a spinnerette plate (4; 24) having a plurality of bores (5; 25), the method comprising: blocking at least one bore (5a; 25a) of said spinnerette plate (4; 24) by installing a sealing plate (10; 30) adjacent to the upstream side of said spinnerette plate (4; 24), the sealing plate (10; 30) having flow channels (11; 31) formed therein, each flow channel (11; 31) corresponding in position to a bore (5; 25) in the spinnerette plate (4; 24), the number of flow channels (11; 31) being less than the number of bores (5; 25) in the spinnerette plate (4; 24), characterized by employing a sealing plate (10; 30) which has non-compound cylindrical flow channels (11; 31). A method according to claim 6, characterized by installing said sealing plate (30) intermediate said spinnerette plate (24) and a metering plate (28) having a plurality of apertures corresponding in number and location to the number and location of the bores (25) in the spinnerette plate (24).

Inventors: ARMSTRONG ROBERT N, FIRST ROBERT E, HODAN JOHN A, ARMSTRONG, ROBERT N., FIRST, ROBERT E., HODAN, JOHN A.
Applicants: BASF CORP, BASF CORPORATION
Application year: 1991
Main classification: D01D4
IPC codes: D01D4, D01D5