UK firm will craft the world`s largest compressor rotors

Three of the largest compressor rotors ever produced are being manufactured by the British helical components specialist, Holroyd. The 4m-long, 816mm-diameter rotors, each weighing more than 4 tonnes, are being made for the compressor division of the German engineering giant, MAN.

The rotors are destined for use gas compressors with flow rates of 200-100,000 cubic metres per hour, and discharge pressures of more than 50 bar.

Holroyd is producing the rotors at its Rochdale site using a modified version of its 8A milling machine - the world`s largest helical profile-machining centre, and the only one that can cut deep helical profiles with diameters above 800mm.

It will take about two weeks to rough-cut each rotor from solid stainless steel blanks. They will then be heat-treated to relieve stress, before being finish-milled. The rotors will be produced in matched pairs with dimensional tolerances to within a few microns.