In the 1970's Biach developed a "quick disconnect" (or quick connect) style stud tensioner for use on reactor
In the 1970's Biach developed a "quick disconnect" (or quick connect) style stud tensioner for use on reactor pressure vessels that represented a new generation of stud engagement. This style produced dramatic time savings for crews since they no longer needed to manually screw-on the tensioner's large puller bar to the RPV stud. Now, they simply flipped a switch to activate a cam driven, split segment style chuck that engaged the studs. This design, though widely used when new plants were being constructed, is not practical for existing plants since it requires new or modified studs to incorporate special annular style grooves to tool engagement.
In 1994, Biach perfected this chuck style latching method for engaging regular, helical thread forms. The Biach QD-H is now in use at nuclear sites in the U.S. that have taken the initiative to upgrade their older, manual systems to incorporate the latest technology and reap the benefits of critical path time savings and reduced man-rem exposure.
Hydraulic return of the piston - this eliminates the need for plant air supply to return the piston after each stroke. At the same time it eliminates the potential for corrosion due to water in air lines and reduces concern for air born contamination from air exhaust.
Hydraulically actuated pull system segments - smoother, faster operation and elimination of corrosion concerns
Communication boxes and limit switches - features that improve the synchronization of operation between tensioner and pump operators.
Torque motor controlled nut seating - assures accurate and repeatable nut seating that is important to consistent stud loading and reduced pass programs to achieve time savings.
Stud engagement now takes less than 5 seconds compared to 3 to 8 minutes of other methods. Adding the Biach EPN pumping system reduces overall operation to 30 seconds per stud set compared to 10 to 15 minutes with other systems.
Biach Industries, Inc., 75 Chestnut Street, P O Box 280, Cranford, NJ 07016. Tel: 908-276-3110; Fax: 908-276-0815.