New fittings eliminate the time-consuming 'coning and threading' practices that usually need to be performed in the field when applying traditional high pressure fittings
Parker Instrumentation has launched what it calls a breakthrough in tube fittings for liquid and gas instrumentation systems, with a new 'rapid assembly' design that will handle pressures up to 15,000psi.
Based on the familiar, industry-standard compression technique - which allows a fitting to be installed in seconds by simply tightening a nut - the new fittings eliminate the time-consuming 'coning and threading' practices that usually need to be performed in the field when applying traditional high pressure fittings.
Among the application sectors that can benefit from this innovation are deepwater oil and gas drilling, and industrial laboratories where products are developed and tested under extreme conditions. Instrumentation engineers working in areas such as these can now assemble tubing systems in a tiny fraction of the time previously required.
They also avoid the need for specialised training in installing traditional high pressure fittings, and the close attention to quality control procedures typically required during assembly.
Dubbed MPI, Parker's new tube fitting range is available in a range of instrumentation sizes to suit tubing with outside diameters from 1/4 to 1 inch, and in a variety of shapes and flow arrangements including straight connections, elbow and tee joints, bulkhead unions, reducers and adapting interfaces. The fittings may be used on cold-drawn hard (unannealed) 316 stainless steel tubing, or thick-walled (annealed) instrumentation-grade 316 tubing.
The fittings also feature nuts coated with molybdenum disulphide, which provides a long-lasting lubricant to help prevent thread galling, and reduces the torque required to create the seal - easing both assembly and the remaking of joints.
MPI's ability to operate at much higher pressures comes from a combination of design factors.
These include: new geometries for the ferrules which create a dual mechanical hold onto the tubing wall; the application of Parker's exclusive Suparcase hardening treatment to both of these ferrules for enhanced ability to bite into tubing; longer tube supporting areas within the fittings to enhance resistance to vibration and line loads; and the use of 'inverted' threads (swapping the sides on which male and female threads are used).
This latter technique allows the pressure-retaining elements of the tube fitting to be made thicker without substantially increasing either the size or weight of the fittings.
"It can take 30 minutes or more to create the cone and thread required for high pressure fittings", says Steve Mullen, Parker's product marketing manager.
"MPI can cut assembly time to seconds, delivering major savings in installation costs, and allowing a common style of tube fittings to be applied plant-wide." Safety assurance was a key goal behind the development of these new high pressure fittings.
As the fittings are based on familiar compression assembly techniques, Parker has designed the component parts in such a way there is no possibility of accidental intermixing with low pressure ferrules for example, or of component interchange with any other fitting (which can be a possibility with products for lower pressure applications).
Furthermore, the maximum working pressures of the parts are printed on the bodies of MPI fittings, along with heat code traceability information.
