Method for inspecting liquids in transparent containers

• US 3,914,058 A
• Filed: 03/03/1971
• Issued: 10/21/1975
• Est. Priority Date: 02/17/1970
• Status: Expired due to Term

• Current Assignee: Emanuel B. Hershberg, Julius Z. Knapp
• Original Assignee: Emanuel B. Hershberg, Julius Z. Knapp
• Inventors: Knapp, Julius Z., Hershberg, Emanuel B.
• Primary Examiner(s): McGraw, Vincent P.
• Assistant Examiner(s): Evans, F. L.
• Application Number:
  US05/120,399
• Time in Patent Office: 1,693 Days
• Field of Search: 250/218,223,224,574 356/103,197
• US Class Current: 356/427
• CPC Class Codes: G01N 21/9009 Non-optical constructional details affecting optical inspection, e.g. cleaning mechanisms for optical parts, vibration reduction
• CPC Class Codes: G01N 21/9027 in containers after filling
• CPC Class Codes: G01N 33/0081 Containers; Packages; Bottles

Abstract

A method for detecting the presence of particulate matter in a liquid contained in a transparent container is disclosed as well as apparatus for performing the method. The preferred method includes the steps of rotating the container at a first relatively low rate of speed, rapidly stopping the container, immediately thereafter inspecting the rotating liquid in the container to determine if relatively lightweight particles are moving in the rotating liquid, rotating the container again to bring it to a second relatively high rate of speed, again rapidly stopping the container, and immediately thereafter inspecting the rotating liquid to determine if there are any relatively heavy particles moving in the rotating liquid.

Claims

1. A method for detecting particulate matter in a liquid in a transparent container which particulate matter may include first particles which will move in the liquid when the liquid is rotated at a first rate and can be easily detected when the liquid is rotating at said first rate, and second particles which will move in the liquid when the liquid is rotated at a second rate different from said first rate and can be easily detected when said liquid is moving at said second rate, said first particles being difficult to detect when the liquid is rotating at said second rate and said second particles being difficult to detect when the liquid is rotating at said first rate, comprising the steps of rotating the container to bring the liquid to at least both said first and second rates of rotation, rapidly stopping the rotation of the container after the liquid has reached each of its said first and second rates of rotation, and immediately inspecting the rotating liquid after each said stopping, said first rate of rotation of said liquid being lower than the said second rate and the said liquid being brought to its first rate of rotation, inspected, then brought to its second rate of rotation and again inspected.

2. A method according to claim 1, wherein said second rate is from two to ten times the said first rate.

3. A method according to claim 1, wherein the step of inspecting the fluid after it has been rapidly stopped includes the use of electro-optical inspection means.

4. A method according to claim 1, wherein the steps of inspecting the liquid each comprise projecting at least two light beams through the container so that they intersect within the liquid and exit therefrom and delineate an angular shadow zone radiating outwardly from said container, and viewing the liquid from a position in said shadow zone and off the path of either of said light beams.

5. A method according to claim 4, wherein said viewing position is also outside of the space defined by the planes of the upper and lower surfaces of the liquid.

6. A method according to claim 4, wherein said light beams illuminate particles to form particle images in said shadow zone, said particle images being passed through means to prevent the passage of those particle images having less than a specified size.