EP0256644A2
Expired / Lapsed
EP
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Method and apparatus for drawing thermoplastic tubing
Assignee: Bayer Corp
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Filing: 1987-06-29
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Granted: —
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Expires: 2007-06-29
Abstract
Abstract Thermoplastic tubing, particularly fluoropolymer tubing, is heated by passage through a liquid bath (20), drawn through a polished die (22ʹ) to reduce its diameter, and then rapidly cooled (27). The drawn tubing may be re-heated to relieve stresses. The tubing produced, which has improved optical, dimensional and surface properties, is particularly useful for automatic continuous flow liquid analysis systems.
Inventors
- 👤 Jan Raczkowski
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 11:29
CPC Classifications
B; B29; B29C; B29C71/00; B29C71/02; B29C35/00; B29C35/02; B29C35/04; B29C35/06; B29C55/00; B29C55/30; B29C2071/022; B29C35/041; B29C35/16; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29L; B29L2023/00; B29L2023/22
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
91 words
A method of drawing thermoplastic tubing to enhance the optical, dimensional and surface properties thereof, said method comprising: (a) heating a thermoplastic resin tube with a high temperature liquid bath, said liquid bath having a temperature at least equal to the transition temperature (as herein defined) of the thermoplastic tube, (b) drawing said tubing through a polished die to reduce the diameter of the tubing, the die preferably having a drawing diameter at least 10% smaller than the diameter of the tube to be drawn; and (c) rapidly cooling the tubing.
Claim 2
Independent Claim
91 words
A method of drawing thermoplastic tubing to enhance the optical, dimensional and surface properties thereof, said method comprising: (a) heating a thermoplastic resin tube with a high temperature liquid bath, said liquid bath having a temperature at least equal to the transition temperature (as herein defined) of the thermoplastic tube, (b) drawing said tubing through a polished die to reduce the diameter of the tubing, the die preferably having a drawing diameter at least 10% smaller than the diameter of the tube to be drawn; and (c) rapidly cooling the tubing.
Claim 3
Dependent Claim
26 words
A method according to claim 1, wherein the thermoplastic tubing is fluoropolymer tubing, and in step (a) the bath has a temperature of at least 150°C.
Claim 4
Dependent Claim
21 words
A method according to claim 1 or 2, wherein the drawn tubing is annealed by re-heating to a stress relief temperature.
Claim 5
Dependent Claim
23 words
A method according to claim 1, 2 or 3, wherein the tubing is first cleaned with a liquid bath before the heating step.
Claim 6
Independent Claim
52 words
A method according to any of claims 1 to 4, which further includes the steps of: (d) measuring the drawn tubing, and (e) varying the draw force supplied to the tubing in responce to the measurements obtained, whereby the drawing force is reduced to increase the final diameter of the drawn tubing.
Claim 7
Independent Claim
37 words
A method according to any of claims 1 to 5, wherein the high temperature liquid is an oil bath, the tubing being immersed in the oil bath preferably for 8-16 seconds immediately prior to the drawing step.
Claim 8
Independent Claim
19 words
A method according to any of claims 1 to 6, wherein the polished die is a polished diamond die.
Claim 9
Dependent Claim
16 words
A method according to claim 2, wherein the high temperature liquid bath is synthetic fluorocarbon oil.
Claim 10
Independent Claim
29 words
A method according to any of claims 1 to 8, wherein the tubing is drawn through the polished die with a gripper pulled by an adjustable speed motor means.
Claim 11
Independent Claim
79 words
A method according to claims 5 and 9 which is carried out continuously and which further includes the steps of optically measuring the diameter of the advancing drawn tubing to generate at least one control signal which is a function of the outside diameter of the drawn tubing, and controlling the adjustable speed motor by said control signal(s), wherein the speed of the drawing motor is slowed to increase the diameter of the drawn tubing to a predetermined dimension.
Claim 12
Dependent Claim
85 words
Apparatus for drawing fluoropolymer tubing to enhance the optical and dimensional properties thereof, said apparatus comprising: (a) a hot oil bath means for heating a fluoropolymer resing tubing to a temperature to at least 180°C, (b) a drawing die, preferably a polished diamond die, positioned immediately adjacent said oil bath means for drawing said fluoropolymer tubing after it has been heated. (c) means (140) for drawing said tubing through said heating means and said drawing die, (d) cooling means (127) for rapidly cooling the tubing.
Claim 13
Dependent Claim
85 words
Apparatus for drawing fluoropolymer tubing to enhance the optical and dimensional properties thereof, said apparatus comprising: (a) a hot oil bath means for heating a fluoropolymer resing tubing to a temperature to at least 180°C, (b) a drawing die, preferably a polished diamond die, positioned immediately adjacent said oil bath means for drawing said fluoropolymer tubing after it has been heated. (c) means (140) for drawing said tubing through said heating means and said drawing die, (d) cooling means (127) for rapidly cooling the tubing.
Claim 14
Dependent Claim
64 words
Apparatus according to claim 11, which further comprises: (a) means (136) for measuring the tubing after it has been drawn, and generating a control signal in response thereto, (b) variable speed motor means (141) responsive to said control signal for varying speed of the means for drawing said tubing, whereby the drawing speed can be decreased to increase the diameter of the drawn tubing.
Claim 15
Dependent Claim
25 words
A fluorocarbon tube having an outside diameter of from .25 to 2.5 mm, a concentricity greater than 95%, and an optical transmittance greater than 90%.
Claim 16
Dependent Claim
25 words
A fluorocarbon tube having an outside diameter of from .25 to 2.5 mm, a concentricity greater than 95%, and an optical transmittance greater than 90%.
References Cited (Backward Citations)
No citation records indexed.
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