INLOK Your Way To Increased RC Inner Tube Life and Higher Safety Standards
Harley Hollier, Technical Director, Harlsan Industries
Summary: The combination of Harlsan INLOK drill rods with inner tube urethane seals or O-rings results in an extremely low maintenance, safe and cost effective reverse circulation drill string. The safety of the INLOK system over traditional methods is a significant additional advantage.
Date: 14 Mar 2013
Key words: Inner Tubes, Urethane Seals, INLOK RC Drill Rods, Reverse Circulation, Drill Rig Safety
Many drill rig operators have resigned themselves to the various operational problems that inner tubes and their sealing systems present. However a combination of material, design and handling advances can virtually eliminate many of these commonplace complications.
The problem of sealing inner tubes in tough drilling conditions
O-rings have long been a tried and tested method for sealing inner tubes. More recently urethane seals have made inroads into the sealing scene. Both systems are capable of effective sealing but each have some individually specific drawbacks.
O-rings can be accidentally hooked out during the rod coupling and uncoupling process. This can occur with urethane seals too but is less likely. O-rings tend to be less visible than urethane seals when located in the box section of inner tubes. This raises the potential for injury if drillers resort to checking for O-rings with their fingers. Overall, while the evidence leans towards urethane seals being a superior sealing method to O-rings, they are more expensive and less widely available than the very familiar O-ring.
Other inner tube wear and tear evils
Over time the sealing performance of inner tubes can fall away due to “ metal grooving” as the seals slowly but persistently rub at the steel surfaces of the inner tube. This problem is accelerated in circumstances where worn or loose fitting inner tubes “move” either by bouncing or spinning. This form of wear further reduces the overall life of the inner tube sealing surfaces and has wear impacts on the outer rod too. The seating for the inner tube within the outer rod becomes worn and even a new replacement inner tube will be loose and immediately capable of movement. Hence the accelerated cycle of wear continues.
Developing an engineered solution
With a firm understanding of the current sealing systems and their respective inherent problems, Harlsan R&D has developed the Harslan INLOK system of dril rods. The INLOK system couples inner tube design changes with an engineered tube placement and removal process. This combination tackles and overcomes the concerns of safe handling while also addressing the broad range of unresolved wear and tear issues. In practice the INLOK System completely locks the RC Inner tube within the body of the RC rod. This stops the inner tubes from moving either up or down, or rotating inside the rod. The elimination of movement inhibits both O-ring and seal grooving of the inner tube ends, and reduces wear to the inside rod shoulder. The problem of air bypass is also solved. Inner tube circlip breakages are virtually eliminated and worn Inner tubes can be inserted and extracted easily and safely without forced manual handling methods.
A big leap ahead for sealing with a new, safer way
INLOK RC drill rods have been adopted by a number of Harlsan customers and proven to be extremely successful. The engineered solution has been a big leap forward for safe handling, effective sealing and inner tube life extension in both O-ring and Urethane seal configurations. While the optimal INLOK configuration is the INLOK inner tubes combined with urethane seals, one of the bonus results has been the success of the system with O-ring sealing systems. This makes the O-ring and INLOK configuration a valuable option for customers that have a preference for staying with O-rings.