Patent Number: 6,167,764

Title: Stud tensioning method

Abstract: The tension in a stud is verified by determining the elongation of the stud while attached to a stud tensioner during the tensioning step. The pressure of hydraulic fluid in a hydraulically actuated tensioner is increased from a first low pressure to a higher pressure for elongating the stud while correlating the increase in pressure of the hydraulic fluid with the quantity of hydraulic fluid in the tensioner or with the displacement of a tensioner puller bar or piston. After a nut is tightened on the stud, the pressure of the hydraulic fluid is reduced from the higher pressure to a second low pressure while correlating the decrease in pressure of the hydraulic fluid with the travel of the puller bar or piston or correlating the decrease in pressure of the hydraulic fluid with the change in fluid volume. The elongation of the stud is then determined as a function of the difference in the correlated quantities of hydraulic fluid or the correlated differences in puller bar or piston travel at the first and second low pressures. Finally, the tensioner is detached from the stud.

Inventors: Calhoun; Gregory L. (North Huntingdon, PA)

Assignee: Westinghouse Electric Company LLC

International Classification: G01L 5/24 (20060101); G01N 3/08 (20060101); G01N 3/00 (20060101); G01N 33/00 (20060101); G01N 003/08 ()

Expiration Date: 01/02/2018