Method and apparatus for measurement and control of cell size in a foam structure

• US 4,412,961 A
• Filed: 12/23/1981
• Issued: 11/01/1983
• Est. Priority Date: 12/23/1981
• Status: Expired due to Fees

• Current Assignee: Exxonmobil Oil Corporation (Exxon Mobil Corporation)
• Original Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Inventors: Krutchen, Charles M., DiBiasi, Daniel J.
• Primary Examiner(s): Anderson, Philip E.
• Application Number:
  US06/334,093
• Time in Patent Office: 678 Days
• Field of Search: 264/40.1, 264/40.4, 264/53, 264/DIG. 13, 425/140, 425/817 C, 356/378, 356/391, 356/256, 356/446, 356/335, 356/448
• US Class Current: 264/40.1
• CPC Class Codes: B29C 44/60 Measuring, controlling or regulating
• CPC Class Codes: G01N 15/0205 by optical means
• CPC Class Codes: Y10S 264/13 Cell size and distribution control while molding a foam

Abstract

A method and apparatus for monitoring the average cell size of a plastic foam structure continuously emerging from a production extrusion source which include means and process steps for magnifying an image of an area of a cross-section of said foam structure, developing said image and comparing the cell size of the image with a known standard and controlling production process parameters to obtain a foam structure of predetermined average cell size.

Claims

1. A method for monitoring the average cell size of a plastic foam structure continuously emerging from a production extrusion source which comprises:

presenting a cross-section of an area of said structure of the in-line extruded product to an optical projection means capable of projecting a magnified image of said area;

projecting a magnified image of said area through said means to a photoreceptor device to form thereon a latent image of said area;

developing said image to form a visible image of said area;

determining the average cell size of said area from said visible image by comparison with a known standard representing exceptable cell size limits; and

in response to said size, controlling process parameters to obtain a foam structure at least generally corresponding to said known standard.

2. The method of claim 1 wherein said images are taken and developed at any time intervals.

3. The method of claim 1 wherein said visible image is a xerographic image.

4. The process of claim 1 wherein said visible image is a chemically developed photographic image.

5. The method of claim 1 wherein said production process parameters are automatically controlled in response to the determined average cell size of said area.

6. An apparatus for controlling the average cell size size of a plastic foam structure continuously emerging from a production extrusion source which comprises:

an optical projector capable of projecting a magnified image of an area of a cross-section of said foam structure of the in-line extruded product;

means for moving a cross-section of said foam structure past said projector;

photoreceptor means in association with said projector and capable of receiving a magnified latent image of said area;

developer means in association with said photoreceptor means capabale of developing said latent image;

measuring means in association with a developed image of said photoreceptor for measuring the average cell size of said area by comparison with a known standard representing exceptable cell size limits; and

control means in association with said measuring means responsive to measurement values to control production process parameters to obtain a foam structure at least generally corresponding to said known standard.

7. The apparatus of claim 6 wherein said photoreceptor means and developing means are part of an electrophotographic system.

8. The apparatus of claim 6 wherein said photoreceptor means and developing means are part of an instant chemical development photographic system.

9. The apparatus of claim 6 wherein said means responding to the measurement value is an automatic means.