- Retrofit for Torqued to Tensioning without replacing studs.
- Standard radial footprint as existing nut.
- Replaces existing hex, 12 point, cap,etc nuts.
- One person installation & removal
No Extended Stud Thread Required
- Utilizes the OD of the nut for tensioner gripping surface.
- Utilized with an External Tensioner (HET) that is removed once tensioning is complete.
- Nut material can be optimized for higher loads or temperature concerns.
The External Tensioned Nut (ETN) design provides a seamless transition
form torqued hardware to tensioned hardware. Until now, it has not been possible
to replace torqued hardware with tensioned hardware unless there was a significant
amount of thread protruding above the nut. Historically, retrofit has been accomplished
by replacing the studs. However with the application of the Riverhawk ETN, this
is no longer the case.
The standard ETN design fits inside the clearance envelope of ANSI standard heavy
hex nuts resulting in a reduction of flange contact stress. The ETN replaces
the existing nut whatever its configuration; hex, 12 point, cap, etc.
In operation, the ETN tensioning system utilizes the nut OD as the gripping surface
for tensioning which eliminates the need for a gripping surface on the stud.
This makes it particularly well suited for retrofit applications. Once the load
cell of the tensioner is applied and the stud is stretched, the retaining ring
is turned down and the stud remains loaded. Note that the load cell is removed
once tensioning has been accomplished, a factor which results in a lower total
cost and eliminates environmental considerations.
If the application requires a smaller envelope or even higher loads in the stud,
there are several options available. These options include the use of a washer
under the nut to distribute the load and higher strength materials to carry the
load with the same factors of safety.