Open Gap HiLo tool
The Open Gap HiLo tool measures the HiLo geometry of pipes aligned for open gap welding. Reducing HiLo improves weld quality. Better welds means stronger, longer lasting pipelines.
Key features
Reduce HiLo
Measurements accurate to +0.05mm
Ensure design specifications are met
Easy to use with magnetic base and calibration/verification stand
Traceable measurements
Range of blades available to suit requirement
Better pipe fit-up
Created in response to customer request, the OMS Open Gap HiLo tool measures the pipe geometry of two pipes aligned for open gap welding to a high degree of accuracy. OMS sales director, Paul Eagle, writes about what HiLo measurement is and why it is important.
Accuracy over 0.05 mm
The tool checks pipes with a bevel. The edges are brought together leaving a small gap of 2 - 3 mm. Probes go through the gap to measure fit-up and ensure it is within desired specifications. Our Open Gap HiLo tool is ideal for critical fatigue-sensitive pipeline sections such as steel catenary risers and has been used around the world by all major pipe-lay companies and welders.
Final check before welding
To achieve a good weld and avoid stress concentration pipes must be matched as accurately as possible. In critical fatigue sensitive pipes the HiLo measurement confirms fit-up predictions from the OMS SmartFit process and provides the last check before pipes are welded. Post-weld, pipes may be checked again with OMS weld inspection technology.
Dial gauge operation
The Open Gap HiLo tool has two small blades with a hook on each end. To operate, it is placed on the pipe and the magnetic clamp activated. A thumbscrew moves the blades directly above the joint between two pipes. The dial gauge, set to register zero when the blades are of equal length, is pushed into the pipe against the force of a spring to the point at which both blades will go through the gap. We then rotate the dial gauge through 90° so that the hooks are able to touch the inside of the pipe as the pressure on the dial gauge is released. The dial gauge shows any mismatch in the blades as a positive or negative number. We can repeat the process as many times as required to provide HiLo spot checks.
Simple pipe inspection
The Open Gap HiLo tool uses standard digital gauges, is simple to operate and will be familiar to pipe inspectors. All OMS tools are sent out calibrated and we provide a yearly calibration and repair service.
“Measuring HiLo just before welding confirms the best fit-up selections for critical fatigue-sensitive pipes and reduces the chance of expensive weld-related cut outs.”
