A NEW series of rigid adjustable type couplings, available through Naismith Engineering and designed for easy axial adjustment of impeller clearance in vertical pump installations, has been introduced by Lovejoy.
As an addition to the Lovejoy/Sier-Bath gear coupling line, the new RA/RAHS Series offers both close-coupled and spacer styles in standard (RA) type and high-speed (RAHS) type, which is specially balanced to API 610 8th edition tolerances.
Spacer styles provide a centre section that can be removed to let the impeller lift out for maintenance without disturbing and having to re-set its vertical clearance adjustment, or demounting either the motor or pump housing.
All styles and types are available in either AISI 1045 steel or stainless steel, for broad application across water, wastewater, power generation, refinery and many other industries.
Rigid hubs with clearance-fit bores and keyways allow easy slide-on, bolt-together installation. Twelve sizes cover bore requirements ranging from 0.44" to 10.5" with square key (or to 276mm with metric key), horsepower-per-100rpm ratings up to 2,164, and thrust capacities up to 400,000lbs.
The upper (motor) hub is indexed to the motor shaft by axial keyway and hangs on a split thrust ring fitted into the shaft's circular keyway. The lower (pump) hub, indexed to the pump shaft by axial keyway, hangs from an adjusting nut turned onto the pump shaft's threaded end.
The adjusting nut has a smooth cylindrical shape matching the hubs' outside diameter, with radial holes to allow turning with a spanner wrench.
After adjustment is set, hubs and adjusting nut are locked together with axial through-bolts. Spacers engage the lower hub's through-bolts on one end and bolt separately to the upper hub on the other end.