Method of continuous operation of a storage tank

• US 5,358,143 A
• Filed: 05/24/1993
• Issued: 10/25/1994
• Est. Priority Date: 07/22/1992
• Status: Expired due to Term

• Current Assignee: Lenzing AG (B & C Privatstiftung)
• Original Assignee: Courtaulds Fibers, Inc.
• Inventors: Perry, Michael R.
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): DeRosa, Kenneth
• Application Number:
  US08/067,330
• Time in Patent Office: 519 Days
• Field of Search: 222/64-66, 222/1, 222/386, 222/386.5, 137/487.5, 141/192, 141/198, 141/94, 141/95, 73/412
• US Class Current: 222/1
• CPC Class Codes: B29C 2948/92076 Position, e.g. linear or angular
• CPC Class Codes: B29C 2948/92161 Volume or quantity
• CPC Class Codes: B29C 2948/92333 Raw material handling or dosing, e.g. active hopper or feeding device
• CPC Class Codes: B29C 2948/92342 Raw material pre-treatment, e.g. drying or cleaning
• CPC Class Codes: B29C 2948/9238 Feeding, melting, plasticising or pumping zones, e.g. the melt itself
• CPC Class Codes: B29C 2948/92476 Fluids, e.g. for temperature control or of environment
• CPC Class Codes: B29C 2948/92657 Volume or quantity
• CPC Class Codes: B29C 2948/92704 Temperature
• CPC Class Codes: B29C 2948/92828 Raw material handling or dosing, e.g. active hopper or feeding device
• CPC Class Codes: B29C 2948/92838 Raw material pre-treatment, e.g. drying or cleaning
• CPC Class Codes: B29C 2948/92876 Feeding, melting, plasticising or pumping zones, e.g. the melt itself
• CPC Class Codes: B29C 2948/92971 Fluids, e.g. for temperature control or of environment
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• CPC Class Codes: B67D 7/02 for transferring liquids other than fuel or lubricants
• CPC Class Codes: B67D 7/36 Arrangements of flow- or pressure-control valves associated with nozzles B67D7/42
• CPC Class Codes: D01F 2/00 Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof

Abstract

A method of storing liquid in a tank, said tank having a moveable follower carrying one of an inlet or outlet port of said tank, said liquid being concurrently and continuously fed to and delivered from said tank and the volume of said liquid in said tank varying in response to variations in the rates of supply and demand.

Claims

1. A method of storing a liquid in a tank, said liquid being concurrently and continuously fed to and delivered from said tank,

said tank having an end and at least one wall,

said tank having an inlet port connected to a source of supply of said liquid and an outlet port connected to a source of demand for said liquid,

said tank containing a movable follower,

one of said inlet port and said outlet port being situate in the vicinity of said end and the other of said inlet port and said outlet port being attached to and movable with said movable follower,

the present volume of said tank being defined by said end, said at least one wall and the present position of said movable follower within said tank, said present volume changing according to said present position of said movable follower,

said method including the steps of:

1. continuously feeding said liquid to said tank from said source of supply, and concurrently therewith

2. continuously delivering said liquid from said tank to said source of demand, and

3. varying said present position of said movable follower within said tank responsive to changes in the volume of said liquid within said tank consequent upon variations in the respective rates of said feed and said delivery, wherein said volume of said liquid within said tank is always the same as said present volume of said tank.

2. A method according to claim 1 wherein said moveable follower is a piston sealing with said at least one wall of said tank.

3. A method according to claim 2 wherein external pressure is applied to said piston.

4. A method according to claim 3 wherein said external pressure is applied to said piston through a central rod.

5. A method according to claim 1 wherein said port attached to and moveable with said moveable follower is connected to said source of supply or to said source of demand by means of telescopic tubing.

6. A method according to claim 5 wherein said telescopic tubing is immersed in said liquid and passes through said end of said tank.

7. A method according to claim 6 wherein said port attached to and moveable with said moveable follower is pivotally attached to said moveable follower.

8. A method according to claim 1 wherein the volume of said liquid in said tank is controlled by regulation of said rate of supply responsive to movement of said moveable follower.

9. A method according to claim 1 wherein said rate of supply is regulated by a volumetric metering pump.

10. A method according to claim 1 wherein said rate of demand is regulated by a volumetric metering pump.

11. A method according to claim 1 wherein said liquid in said tank is in a substantially laminar flow regime.

12. A method according to claim 11 wherein said liquid is a polymer dope for the manufacture of regenerated cellulose fibre or film.

13. A method according to claim 12 wherein said liquid is a solution of cellulose in a tertiary amine N-oxide.