System for determining tube eccentricity

• US 4,027,527 A
• Filed: 04/01/1975
• Issued: 06/07/1977
• Est. Priority Date: 04/01/1975
• Status: Expired due to Term

• Current Assignee: Aluminum Company of Egypt
• Original Assignee: Aluminum Company of Egypt
• Inventors: Stricker, David M., Bennett, Robert F., Brouwer, Nicholaas L.
• Primary Examiner(s): Ruehl, Charles A.
• Application Number:
  US05/564,056
• Time in Patent Office: 798 Days
• Field of Search: 73/67.5 R, 73/67.8 S, 73/67.9, 73/67.7
• US Class Current: 73/622
• CPC Class Codes: G01B 17/02 for measuring thickness
• CPC Class Codes: G01B 5/252 for measuring eccentricity, i.e. lateral shift between two parallel axes
• CPC Class Codes: G01B 7/06 for measuring thickness measuring during the manufacture of coatings C23C14/54
• CPC Class Codes: G01B 7/312 for measuring eccentricity, i.e. lateral shift between two parallel axes

Abstract

A system for determining the eccentric characteristics of a tube wall comprising a positioning assembly supported by the tube which is moving in its lengthwise direction, and a plurality of thickness sensors supported by the positioning assembly having sensing axes disposed in predetermined angular relation with respect to one another for continuously measuring the wall thickness of the tube at predetermined angular locations about its periphery as it moves in its lengthwise direction. A signal processing means is provided for continuously computing the eccentricity characteristics of the tube based entirely upon the comparative values of the thickness readings of the sensors.

Claims

1. A system for determining eccentricity characteristics of a tube comprising,

a frame,

sensing means mounted on said frame for sensing the thickness of a wall of a tube, said sensing means including at least three thickness sensors supported in sensing position with respect to said tube at predetermined angularly spaced locations with respect to each other and with the axes of the sensors intersecting at substantially the same point for producing output signals which are related to the thickness of the tube wall at the locations sensed and,

signal processing means for receiving the output signals from said sensors and translating these output signals into vector components of the eccentricity of the tube, and for summing said vector components to provide an eccentricity signal related to the magnitude and angular location of the tube eccentricity.

2. A system in accordance with claim 1, wherein

the sensing means comprises ultrasonic sensors for sensing the thickness of the wall of the tube.

3. The system of claim 1, wherein

the sensing means includes at least one mounting head adapted to support the sensors in predetermined angular relationship to each other and in radially spaced relationship to the tube.

4. A system in accordance with claim 1, wherein

said sensing means includes a plurality of sensor mounting heads for supporting said sensors, and

said mounting heads are designed for movement toward and away from one another to move said sensors between the sensing position and a non-sensing position with respect to said tube.

5. A system in accordance with claim 1, wherein

said sensing means includes guide means for maintaining a predetermined spaced relation between said sensors and said tube as said tube moes in a direction of its lengthwise axis.

6. A system in accordance with claim 1, wherein said sensing means comprises three sensors for sensing the thickness of the tube wall at 120°

intervals thereabout.

7. A system in accordance with claim 1, wherein said sensing means comprises four sensors for sensing the thickness of the tube wall.

8. A system in accordance with claim 7, wherein

said sensing means comprises four sensors for sensing the thickness of the tube wall at 90°

intervals thereabout.

9. A system in accordance with claim 1, wherein

said signal processing means includes comparator means for establishing a reference signal related to the maximum allowable eccentricity, and

indicating means for receiving said reference signal and said eccentricity signal and producing an output signal when said eccentricity signal exceeds said reference signal for operating a visual and/or audio indicator.

10. A method for determining eccentricity characteristics of a tube along the lengthwise axis of the tube, comprising

moving a tube relatively to a thickness sensing assembly, including at least three thickness sensors, in the direction of the lengthwise axis of the tube,

sensing the thickness between the outer and inner wall of the tube by said sensors at not less than three locations having predetermined angular spacing around the tube along axes intersecting at substantially the axial center of one wall of the tube, and

determining the eccentricity of the longitudinal central axis of the other wall relative to the longitudinal central axis of said first mentioned wall, in magnitude and direction, by transforming the values of said sensed thicknesses into eccentricity vector components and utilizing the vector components to determine the magnitude and angular location of the tube eccentricity.

11. A method in accordance with claim 10, wherein

the average wall thickness is combined with said vector components in determining the angular location of the tube eccentricity.

12. A method for determining eccentricity characteristics of a tube along the lengthwise axis of the tube comprisingthe steps of,

moving a tube relative to a thicknes sensing assembly, including at least three thickness sensors, in the direction of the lengthwise axis of the tube,

sensing the thickness of the wall of the tube by said sensors at not less than three locations having predetermined angular spacing around the tube, and along axes which extend substantially radially of said tube,

determining the magnitude of the eccentricity of said tube by summing eccentricity vector components calculated from the thickness values sensed at said locations,

determining the average tube wall thickness on the basis of the thickness values sensed, and

determining the percent of eccentricity by the ratio of the magnitude of the eccentricity to the average tube wall thickness.

13. A method for determining eccentricity characteristics of a tube along the lengthwise axis of the tube comprising the steps of,

moving a tube relatively to a thickness sensing assembly, including at least three thickness sensors, in the direction of the lengthwise axis of the tube,

sensing the thickness of the wall of the tube by said sensors at not less than three locations having predetermind angular spacing around the tube, and along coordinate axes which extend substantially radially of said tube,

determining the magnitude of the eccentricity of said tube by summing eccentricity vector components calculated from the thickness values sensed at said locations, and

determining the angular location of eccentricity of said tube wall by determining the ratio or ratios of magnitude of said vector components along said coordinate axes.

14. A method-for determining the eccentricity characteristics of a tubing product, the steps comprising,

providing a sensor assembly including at least three thickness sensors,

moving said tubing product in a lengthwise direction with respect to said sensors,

positioning said sensors so as that each sensor senses along a path defining an axis which extends radially of the tubing product with the axes of the sensors intersecting at substantially the center of said tubing product,

sensing the thickness of the wall of the tubing product by said sensors at not less than three locations for producing output signals which are related to the thickness of the tubing wall at the locations sensed,

receiving the thickness related signals from said sensors and translating these thickness signals into vector components of the eccentricity of the tubing product, and

summing said vector components to provide the eccentricity value and its angular location respect to the tubing product.