If any company has put fasteners to the test, it's been Grand Island, New York-based Viatran Corp., a leading manufacturer of pressure transducers/transmitters for the oil, auto, and wastewater industries. In harsh oil field pumping applications where there is 10,000/15,000-PSI pressure, severe shock, and continuous vibration several Viatran level and pressure sensors are protected by encapsulating "shells" held together by Locking Fasteners.
"The fasteners used to encapsulate and protect the sensors must be back-out proof," says Mike Hallock, Viatran's Purchasing Manager. "Every hour of down time costs thousands of dollars in the oil industry."
There are no threads on the particular fastener Viatran uses. Instead, the fastener is a locking system that acts like a small wrench locked onto a bolt head, with wrench handle braced against a stationary object, such as a frame, casting, or protrusion.
Prior to using his current fasteners from STAGE 8, Viatran tested typical fasteners such as split washers and chemical bonds, finding that these failed to adequately hold each sensor's encapsulating shell together. Viatran settled on a lockwire system to encapsulate and protect its sensors in the field. But this was cumbersome to install, and tended to damage the outside of each sensor on removal for repair. Consequently, repairs had to be done by Viatran in its manufacturing facilities, adding to overall repair times.
As part of a 'down-and-dirty' shock test on Stage 8 locking fasteners, the transducer was mounted on a fixture with a Weco nut-this was accomplished by fastening the nut on the outside diameter of transducer-and pounded with a 10-lb sledgehammer to simulate the punishment it would receive in field installation. When customers beta-testing the improved fastening method gave it a thumbs up, Viatran adopted it for its oil field applications.
"Reliability is what we base our reputation on," explains Hallock. "For the reliability our customers need, we need absolute joint integrity. That's what we got. Not a single fastener has failed in the field for 15 years. That's how we like it."
STAGE 8's counterbore application eliminates the need for labor intensive bolt re-tightening--requiring just a small milled slot adjacent to the counterbore for the retainer to slip into--fasteners can simply be scanned by eye to check for joint integrity.