Bad experience with the reliability of a vane air motor prompted oil and gas well services company, Blue Manta International, to look for a better performing alternative.
Vane air motors are ideal for operation in ATEX environments but the existing model was proving inefficient in extreme conditions, a problem exacerbated by its inaccessibility for repair and maintenance. Both were resolved when the company switched to a Huco Dynatork piston air motor.
Air motors are used by Blue Manta to tension cable as it is lowered into the well which can be offshore or in the desert. In both environments the efficiency of the vane motor was compromised by the extreme conditions. Its design makes it very difficult to seal, exposing the unit to the ingress of salt water and sand. By the same token air is lost to the atmosphere rather than being converted into motion.
A piston air motor is immune to such problems. The operating principle of the product is simple. Via an integral rotary valve, air up to 100 psi is supplied to each of three pistons in turn. The free floating pistons transmit torque on start-up that can be adjusted via a pressure regulator. This results in high torque at variable low speed.
As the motor traps the compressed air within the cylinder, maximum energy conversion is assured. The design is also easily sealable so not only does it consume up to 80% less air than its vane counterpart, it is also far more reliable in hostile environments.
Another important design feature of the latest generation of Huco Dynatork piston motors is their internal pneumatic porting. Competitors’ products still have porting external to the housing and this makes the units more sensitive to temperature extremes and also prone to damage.
The model of piston motor that Blue Manta chose is manufactured in stainless steel and supplied with a helical gearbox. For 80% - 90% of its utilisation, the unit serves as a back stop when the reel is in a holding position. Unlike a DC motor in a similar application, the piston air motor will not burn out or cause overload. And thanks to its sealed body it is proving highly reliable and cost efficient in the field.