DEVICE FOR DEGASSING POLYMER MELTS

• US 20150343672A1
• Filed: 12/05/2013
• Published: 12/03/2015
• Est. Priority Date: 01/10/2013
• Status: Active Grant

• Current Assignee: Bruckner Maschinenbau GmbH & Co. KG (Brückner Group GmbH /Siegsdorf/)
• Original Assignee: Bruckner Maschinenbau GmbH & Co. KG (Brückner Group GmbH /Siegsdorf/)
• Inventors: RABISER, Bernhard, SCHWUCHOW, Rainer
• Granted Patent: US 9,975,278 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 19/0073 by a method not covered by groups B01D19/0005 - B01D19/0042
• CPC Class Codes: B01D 5/0012 Vertical tubes
• CPC Class Codes: B29B 7/728 Measuring data of the driving system, e.g. torque, speed, power, vibration B29B7/724 takes precedence
• CPC Class Codes: B29B 7/826 Apparatus therefor
• CPC Class Codes: B29B 7/84 Venting or degassing ; Removing liquids, e.g. by evaporating components
• CPC Class Codes: B29B 7/845 Venting, degassing or removing evaporated components in devices with rotary stirrers
• CPC Class Codes: B29B 7/88 Adding charges , i.e. additives
• CPC Class Codes: B29B 7/94 Liquid charges
• CPC Class Codes: B29C 37/006 Degassing moulding material or draining off gas during moulding venting means in moulds B29C33/10
• CPC Class Codes: B29C 48/27 Cleaning; Purging; Avoiding contamination
• CPC Class Codes: B29C 48/767 through a degassing opening of a barrel

Abstract

An improved device for degassing polymer melts is characterised by, inter alia, the following features: the at least one vacuum separator comprises cooling pipes extending parallel to each other in the tank interior of the vacuum separator housing, the cooling pipes are double-walled, the cooling pipes end at a distance above a collection chamber or above the tank bottom of the vacuum separator housing, and a cleaning device having a scraper or a wiper is provided, said cleaning device being adapted to the cross-sectional shape of the cooling pipes and preferably to the course of the inner wall of the vacuum separator housing and being movable at least in a partial height at least to the lower end of the cooling pipes.

Claims

1. Device for degassing polymer melts, in particular for the purpose of continuous post-processing to form drawn polymer films, comprising the following features:

a plasticising unit is provided,

at least one vacuum region is associated with the plasticising unit,

the at least one vacuum region is furthermore connected to a vacuum system via a vacuum line or degassing line at least via one vacuum separator, and

the at least one vacuum separator comprises a vacuum separator housing having a gas inlet and a gas outlet, the gas inlet being at least indirectly connected to the vacuum region and the gas outlet being at least indirectly connected to the vacuum system,

characterised by the following further features;

the at least one vacuum separator comprises cooling tubes which extend in parallel with one another in the container inner chamber of the vacuum separator housing,

the cooling tubes have a double-wall design and comprise an outer tube, in which an inner tube extends, thereby forming a space, in such a way that coolant flows into the space between the outer tube and the inner tube via an outer tube supply line, and such that, inside the outer tube, said coolant can be recirculated into the inner tube via a remote circulation connection, and from there, in the opposite direction, to a coolant outlet, or vice versa,

the cooling tubes terminate at a spacing above a collection chamber or above the container floor of the vacuum separator housing, and

a cleaning device is provided, which comprises a scraper or a wiper, is adapted to the cross-sectional shape of the cooling tubes and preferably to the course of the inner wall of the vacuum separator housing, and is movable at least in one partial vertical portion as far as to the bottom end of the cooling tubes.

2. Device according to claim 1, wherein the vacuum separator housing has a double-wall design, specifically having a container outer wall and a container inner wall, it being possible to recirculate coolant between a coolant supply line and a coolant discharge line by means of the housing wall inner space therebetween.

3. Device according to claim 1, wherein the cleaning device comprises a wiper or scraper for cleaning the inner wall of the vacuum separator housing, or in that an additional cleaning device is provided for cleaning the inner wall of the vacuum separator housing, which device can be operated in parallel with the longitudinal extent of the cooling tubes.

4. Device according to claim 1, wherein the cooling tubes extend in parallel with one another and in the process are aligned vertically or are arranged at an angle with respect to the vertical, the angle of inclination with respect to the vertical being less than 45°

, in particular less than 30° and

more particularly less than 15°

.

5. Device according to claim 1, wherein the bottom end or bottom edge of the cooling tubes terminates at such a vertical spacing from the housing floor that the gas inlet is arranged below the height line formed by the bottom end or bottom edge of the cooling tubes.

6. Device according to claim 1, wherein the gas outlet is provided in the upper region of the vacuum separator housing.

7. Device according to claim 1, wherein a cleaning opening is provided in the vacuum separator housing and is arranged below the bottom end or bottom edge of the cooling tubes in the housing floor or in a side wall portion of the vacuum separator housing.

8. Device according to claim 1, wherein the cleaning device comprises a segmented wiper or scraper or a wiper or scraper that has been divided at least into two, the wiper parts or scraper parts of which are fastened to a common operating means so as to be offset from each other in the longitudinal direction of the cooling tubes, or are movable together in the longitudinal direction of the cooling tubes.

9. Device according to claim 1, wherein the cleaning device is provided having at least two cleaning drives having at least two wipers or scrapers which can be moved separately from each other, wherein each of the two wipers or scrapers is only assigned to a part of, preferably only to half, the cooling tubes and/or the housing inner wall of the vacuum separator housing.

10. Device according to claim 1, wherein the at least one or the at least two vacuum separators, which are connected in parallel with one another, form a first filter stage, to which is assigned a second filter stage having at least one and preferably two filters which are operated in parallel with one another.

11. Device according to claim 10, wherein a vacuum line leading to the vacuum system is assigned in each case to the at least one and to the preferably two filters, which are connected in parallel with one another, of the second filter stage, said line preferably leading to the vacuum system via a connection point.

12. Device according to claim 10, wherein, downstream of the filter stage, there is connected a plurality of vacuum lines, which extend in parallel with one another and in each of which there is provided a valve which can move between an open position and a closed position and a pressure sensor in line portions between the at least one vacuum region and the vacuum system, specifically

in the region of the at least one vacuum region or of the vacuum line or degassing line,

between the first and second filter stage and/or

in the vacuum lines which are connected directly upstream of the vacuum pumps, preferably between the valves which are upstream in the suction direction and the vacuum pumps.

13. Device according to claim 1, wherein a valve, which can move between an open position and a closed position, is connected upstream of the first filter stage or of the vacuum separators belonging to the first filter stage, and an additional valve, which can move between an open position and a closed position, is connected downstream of the at least one or the at least two filters of the second filter stage.

14. Device according to claim 1, wherein the valves can be operated by means of a drive, in that the cleaning device can be operated by means of the same drive or a separate drive, and in that a control device is provided which can operate the drive on the basis of measured pressures in line portions, for which purpose pressure sensors are provided in the line portions preferably between the first and second filter stage and in the line portions upstream of the vacuum pumps.