US4244897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus to control the density of products produced from an extrusion process
Assignee: Honeywell Measurex Corp
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Filing: 1979-03-22
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Granted: 1981-01-13
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Expires: 1999-03-22
Abstract
Abstract Density of products produced from a foam extrusion process is controlled by measuring the thickness and the basis weight. The density is calculated and is compared to a target, or desired value, to produce an error signal. The error signal is used to control the density.
Inventors
- 👤 William S. Moon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:09
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/60
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
186 words
A method for continuously and automatically controlling the product from a foam extrusion process to maintain the density of said products at a pre-determined value, said process has an extruder wherein resin and additives are introduced and are heated, a blowing agent is then introduced, and is mixed with the resin and additives to form a mixture, said mixture is cooled and is extruded to produce said product; said method comprising: continuously measuring the weight per unit area of said product by a basis weight sensor and generating an electrical signal related thereto; continuously detecting the thickness of said product by a thickness sensor and generating an electrical signal related thereto; generating an electrical signal related to the calculated value of density of said product based upon the electrical signal related to said basis weight measured and the electrical signal related to said thickness detected; comparing the electrical signal related to said calculated density value to an electrical signal related to said predetermined density value to produce an error signal; and controlling the density of the product produced by said process based upon the error signal.
Claim 2
Independent Claim
186 words
A method for continuously and automatically controlling the product from a foam extrusion process to maintain the density of said products at a pre-determined value, said process has an extruder wherein resin and additives are introduced and are heated, a blowing agent is then introduced, and is mixed with the resin and additives to form a mixture, said mixture is cooled and is extruded to produce said product; said method comprising: continuously measuring the weight per unit area of said product by a basis weight sensor and generating an electrical signal related thereto; continuously detecting the thickness of said product by a thickness sensor and generating an electrical signal related thereto; generating an electrical signal related to the calculated value of density of said product based upon the electrical signal related to said basis weight measured and the electrical signal related to said thickness detected; comparing the electrical signal related to said calculated density value to an electrical signal related to said predetermined density value to produce an error signal; and controlling the density of the product produced by said process based upon the error signal.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said controlling step comprises: adjusting the amount of blowing agent introduced into the extruder.
Claim 4
Dependent Claim
37 words
The method of claim 2 wherein the electrical signal related to the calculated value of density is based upon an operation of: dividing the weight per unit area that is measured by the thickness that is detected.
Claim 5
Independent Claim
184 words
An apparatus for continuously and automatically controlling products produced from a foam extrusion process to maintain the density and thickness of each of said products at a predetermined value, said process has an extruder wherein resin and additives are introduced and are heated, a blowing agent is then introduced into the extruder and is mixed with the resin and additives to form a mixture, said mixture is cooled and is extruded to produce said product; said apparatus comprising: basis weight sensor capable of measuring the weight per unit area of said product and generating an electrical signal related thereto; thickness sensor capable of detecting the thickness of said product and generating an electrical signal related thereto; a density calculator capable of calculating the value of density of said product from said above electrical signal and generating a signal corresponding to the calculated density value; means for comparing said calculated density value to an electrical signal related to said predetermined density value to produce an error signal; and means for controlling the density of the product produced by said process based upon said error signal.
Claim 6
Independent Claim
184 words
An apparatus for continuously and automatically controlling products produced from a foam extrusion process to maintain the density and thickness of each of said products at a predetermined value, said process has an extruder wherein resin and additives are introduced and are heated, a blowing agent is then introduced into the extruder and is mixed with the resin and additives to form a mixture, said mixture is cooled and is extruded to produce said product; said apparatus comprising: basis weight sensor capable of measuring the weight per unit area of said product and generating an electrical signal related thereto; thickness sensor capable of detecting the thickness of said product and generating an electrical signal related thereto; a density calculator capable of calculating the value of density of said product from said above electrical signal and generating a signal corresponding to the calculated density value; means for comparing said calculated density value to an electrical signal related to said predetermined density value to produce an error signal; and means for controlling the density of the product produced by said process based upon said error signal.
Claim 7
Dependent Claim
23 words
The apparatus of claim 1 wherein said controlling means comprises means for adjusting the amount of resin and additives introduced into said extruder.
Claim 8
Dependent Claim
18 words
The apparatus of claim 1 wherein said controlling means comprises means for adjusting the temperature of said mixture.
Claim 9
Dependent Claim
22 words
The apparatus of claim 1 wherein said controlling means comprises means for adjusting the amount of blowing agent introduced into said extruder.
Claim 10
Dependent Claim
52 words
The apparatus of claim 7 wherein said basis weight sensor comprises a radiation source to one side of said product, capable of emitting a beam of radiation through said product; and a radiation detector to the other side of said product capable of detecting the amount of radiation transmitted through said product.
Claim 11
Dependent Claim
14 words
The apparatus of claim 8 wherein said thickmess sensor comprises a non-contacting caliper gauge.
Claim 12
Dependent Claim
14 words
The apparatus of claim 8 wherein said thickness sensor comprises a contacting caliper gauge.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |