Spin beam for spinning synthetic filament yarns

Details Spin beam for spinning synthetic filament yarns Spin beam for spinning synthetic filament yarns

1999-06-18

2001-07-17

Nguyen, Nam (Department: 1722)

Plastic article or earthenware shaping or treating: apparatus

Stock pressurizing means operably associated with downstream...

Including heating or cooling means

C425S382200, C425S464000

Reexamination Certificate

active

06261080

ABSTRACT:

BACKGROUND OF THE INVENTION
The invention relates to a spin beam for spinning a plurality of synthetic filament yarns and more particularly to an improved melt distribution system for such a spin beam.
A spin beam is known from U.S. Pat. No. 4,035,127, wherein a melt distributor block mounts in series a plurality of spinnerets. Each of the spinnerets is connected via a melt line to a spin pump, which is likewise mounted on the melt distributor block. The melt lines are formed substantially by bent pipes arranged in one plane. This arrangement involves the problem that the melt lines exhibit cross sectional variations due to the fact that the pipes are bent to a greater or lesser extent. However, for spinning a plurality of yarns it is necessary that each spinneret receive a quantitatively and qualitatively equivalent melt flow.
U.S. Pat. No. 5,354,529 discloses a spin beam, wherein each melt line between the spin pump and the spinnerets is formed by a bore in the melt distributor block. However, this layout involves the problem that the lengths of the melt lines between the spin pump and the spinnerets differ in a serial arrangement of a plurality of spinnerets. A further disadvantage of this layout is that sediments form in blind holes that are necessitated by manufacture.
It is therefore the object of the invention to further develop a spin beam of the initially described type in such a manner so as to permit even distribution of the melt from one spin pump to a plurality of spinnerets, so that each spinneret receives a qualitatively and quantitatively equivalent melt.
SUMMARY OF THE INVENTION
The above and other objects and advantages of the present invention are achieved by the provision of a spin beam which comprises a melt distributor block which has a plurality of melt distributor lines which extend respectively between one of the discharge outlets of the spin pump and an associated spinneret. The melt distributor block comprises two structural members which are interconnected in a pressure tight manner along a separating line, and each of the distributor lines includes a segment which extends along the separating line. In a preferred embodiment, these segments of the distribution lines are formed as a groove in one or both of the opposing surfaces defined by the structural members at the separating line.
With the above construction, it is accomplished that the respective deflections do not lead to cross sectional variations in the melt lines. Furthermore, the configuration facilitates construction of melt lines with very uniform cross sections. Consequently, each spinneret receives an equal melt flow. Furthermore, the arrangement of the melt lines in the distributor block has the advantage of achieving a high temperature stability in the melt due to the large mass of the block. The separating line between the structural members may be made horizontal or vertical.
When the grooves are arranged in the surface of the structural members, a hydraulically favorable transition is produced between the melt channels and the grooves. Of advantage is a construction, wherein the groove is exclusively formed in one of the structural members, in particular in the case of rectangular groove cross sections.
The segment of each distributor line which extends along the separating line may comprise a pipe which is positioned in a groove in one or both of the opposing surfaces. In this embodiment, the pipes are constructed only with thin walls, since they are supported by the structural members when pressure is applied. In the region of the pipes, it is not necessary to adapt the surfaces of the structural members for purposes of sealing a gap. The grooves can be realized in a simple manner as regards their manufacture, and they can be molded into the surface.
In another embodiment of the invention, a plate is positioned between the opposing surfaces along the separating line. This is advantageous when the opposing surfaces exhibit irregularities which can lead to leakage. To this end, the plate is constructed, preferably of a material, which is softer than the basic material of the structural members. In this connection, the grooves may be machined out of the surface of the plate in the form of flutes, or they may be provided in the plate as continuous grooves. In the case of continuous grooves, same are defined by the surfaces of the structural members. When providing flute-type grooves on the surface of the plate, bores are arranged, so as to interconnect the grooves between the structural members.
In a preferred embodiment of the spin beam, at least one of the opposing surfaces comprises two surface regions separated by a shoulder. Thus the contact surface area of the outermost surface region is reduced, so as to increase contact pressure. This allows to achieve a great sealing effect in the separating line.
The separating line may extend in a plane which is oblique to the horizontal. This prevents the melt flow from having to advance through 90° -deflections on its passage from the spin pump to the spinneret. Moreover, the melt line has a gradient between the spin pump and the spinneret. This will facilitate complete outflow of the melt without further auxiliary means from the spin beam, for example, when the spin line is shut down.
It has shown that preferably a gradient in the range of about 30° effects a satisfactory flow distribution.
The two structural members of the melt distributor block may be divided by a generally horizontal separating line to define an upper structural member and a lower structural member. In such embodiment, a favorable flow pattern is achieved by having the spin pump mounted to the upper structural member and the spinnerets mounted to the lower structural member. Also, the spin pump may be laterally offset relative to the spinnerets, which may be serially arranged on the spin beam, for example, side by side.
The melt supply line for the spin pump may include an inlet end in the upper structural member so that the melt supply line is located wholly within the upper structural member. This permits the overall height of the spin beam to be minimized.
Alternatively, the lower structural member may house the inlet end of the melt supply line so as to keep the spacing between the melt channels exiting from the pump as small as possible.
A very compact construction is realized in particular in that the spin pump is constructed as a gear-type distribution pump. In this construction, the contact surface of the pump on the upper part of the melt distributor block is a flat surface, which is in contact with the pump gears. As a result, a very stable plate-type construction is realized, so that due to a small thermal lag, very small clearances and, thus, very high sealing effects are obtained in the pump. However, it is also possible to mount the pump with an intermediate plate to the spin beam. This has the advantage that the pump may be handled as a complete unit.
The melt lines in the distributor block have a constant inside cross section over the length of the melt line. Thus, the melt flow is substantially identical in all melt lines. A favorable flow pattern results in particular when the inside cross sections of the melt lines are circular. However, it is likewise possible to realize without substantial expenditure cross sections in the form of an ellipsis, semicircle, rectangle, square, etc.
The lengths of the melt lines between the spin pump and the spinnerets are substantially the same, so that the dwelling time of the melt in the melt lines is substantially the same. The connection of the melt line to the spin pump as well as to the spinnerets is realized by the substantially vertically extending melt channels. This allows to ensure a flow-favorable outflow as well as a flow-favorable inflow.


REFERENCES:
patent: 3492692 (1970-02-01), Soda et al.
patent: 3601846 (1971-08-01), Hudnall
patent: 3824050 (1974-07-01), Balk
patent: 3864068 (1975-02-01), Flakne
patent: 4035127 (1977-07-01), Ogasawara et al.
patent: 5354529 (1994-10-01), Berger et al.
patent: 5

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