Thermoplastic melt apparatus

• US 3,938,924 A
• Filed: 03/28/1974
• Issued: 02/17/1976
• Est. Priority Date: 03/28/1974
• Status: Expired due to Term

• Current Assignee: Celanese Corporation
• Original Assignee: Celanese Corporation
• Inventors: Dodson, Keith D., Richardson, Jerry G., Abella, Richard M.
• Primary Examiner(s): Spicer, Jr., Robert L.
• Application Number:
  US05/455,763
• Time in Patent Office: 691 Days
• Field of Search: 425/147, 425/197, 425/198, 425/199, 425/DIG. 200, 425/376, 425/382.2
• US Class Current: 425/147
• CPC Class Codes: B01D 35/12 Devices for taking out of action one or more units of multi- unit filters, e.g. for regeneration
• CPC Class Codes: B29B 13/10 by grinding, e.g. by triturating; by sieving; by filtering
• CPC Class Codes: D01D 1/106 Filtering

Abstract

An apparatus for the continuous filtration and flow of molten thermoplastic polymer from a melt source to a shaping apparatus. The apparatus is characterized by the employment of a melt reservoir whose level is regulated by a level control means. Melt flow to the shaping apparatus is regulated by the level control means which controls the flow rate from the melt source as a function of the level in the melt reservoir.

Claims

1. An assembly for the continuous filtration and transport of a thermoplastic melt from a melt source to a shaping apparatus comprising:

a melt source providing a continuous flow of a thermoplastic melt;

a diverting means disposed downstream of said melt source providing communication for said melt between said melt source and at least two parallel disposed conduits;

at least two parallel disposed conduits, each provided with a removeable filter means, wherein said thermoplastic melt stream is filtered;

a melt reservoir in communication with the downstream end of each of said parallel conduits, said reservoir providing a pool for storage of a fixed volume of said filtered thermoplastic melt;

a level controlling means, in control communication with said melt reservoir and said melt source said level controlling means regulating the melt output of said melt source as a function of the level in said melt reservoir to insure a uniform melt flow to said melt reservoir;

a positive displacement pumping means in communication with the outlet of said reservoir, said pumping means providing the motive force to provide a uniform rate of flow of said melt to a shaping apparatus; and

said shaping apparatus in communication with the discharge out of said positive displacement pumping means, for shaping said thermoplastic melt, which flows into said shaping apparatus at a uniform rate, into a shaped article.

2. An assembly in accordance with claim 1 including a polishing filter disposed in the conduit providing communication between said positive displacement pumping means and said shaping apparatus, said polishing filter provided for the removal of impurities formed downstream of said filters disposed in said parallel conduits.

3. An assembly in accordance with claim 1 wherein said melt source is a polymerization reactor.

4. An assembly in accordance with claim 1 wherein said melt source is a melt extruder.

5. An assembly in accordance with claim 1 wherein said diverting means is a three-way valve.

6. An assembly in accordance with claim 1 wherein said removable filter means, disposed on said parallel conduits, comprises fine porosity sintered metal filters.

7. An assembly in accordance with claim 6 wherein said fine porosity sintered metal filters remove from said thermoplastic melt gels, degradation products and foreign particles having a size in excess of 10 to 15 microns.

8. An assembly in accordance with claim 1 wherein each of said parallel conduits discharge said melt into said melt reservoir at a height in said reservoir equivalent to the melt level in said reservoir.

9. An assembly in accordance with claim 8 wherein said melt reservoir is provided with a plurality of standpipes, equal in number to the number of parallel conduits feeding into said melt reservoir, each one of said standpipes connected to one of said parallel conduits, said standpipes having an outlet for flow of said thermoplastic melt at approximately the melt level in said reservoir.

10. An assembly in accordance with claim 1 wherein said melt reservoir is a closed vessel provided with an inert gas atmosphere in the space above the melt level.

11. An assembly in accordance with claim 1 wherein said level controlling means comprises a differential pressure level controller.

12. An assembly in accordance with claim 1 wherein said level controlling means comprises a nuclear level gauge controller.

13. An assembly in accordance with claim 1 wherein said positive displacement pumping means comprises a gear pump.

14. An assembly in accordance with claim 1 wherein said shaping apparatus comprises a die.

15. An assembly in accordance with claim 1 wherein said shaping apparatus comprises a spinneret.

16. An assembly in accordance with claim 1 wherein said diverting means is a pump disposed at the upstream end of each of said parallel disposed conduits.