PUMP FEATURES

THE SINGLE SHAFT ADVANTAGE

Driving a pump with a steam turbine compared to an electric motor makes good sense. For example, the pump speed can be varied to match load requirements, thus maximizing efficiency. Furthermore, the use of steam to drive a pump can significantly reduce electrical energy consumption and operation costs. However, coupling a pump to a steam turbine is not without its problems. If one manufacturer produces the turbine, another the pump and still others supply the base plate assembly, control system and coupling, these multi-sourced components combined with temperature differentials across the unit will result in alignment and reliability problems as well as a unit that is difficult to operate and maintain.

These challenges led the design engineers at Coffin to develop an innovative alternative to the traditional flexible coupled pump - a close coupled design featuring both the pump and steam turbine mounted together on a single, center supported, rigid shaft. The design concept eliminates the coupling, and, because the pump and the turbine are solidly aligned and center supported, they are unaffected by temperature differences. Alignment problems are eliminated and a Coffin pump can be "cold started" to maximum capacity in a matter of seconds.

From the initial review of customer specifications, the pump, turbine, and associated controls are designed and tested as a single integral unit. This means easy, single source responsibility for initial purchase, parts, and service.

IMPELLERS

Designed with near perfect axial thrust balance, Coffin impellers of either single or double suction type are splined to the shaft and dynamically balanced prior to assembly or shipment.

TURBINE WHEEL

Coffin's forged turbine wheel with fir tree rooted buckets is manufactured in our facility to exacting tolerances and is dynamically balanced prior to assembly or shipment,

BEARINGS

Coffin's special bearings are heavy duty ABCE5 tolerance bearings designed for high speed, high temperature applications. These precision bearings permit closer wear ring clearances providing less internal leakage and improving pump efficiency.

LUBE OIL SYSTEM

Coffin's lube oil system is integrally designed with the pump and configured to individual customer requirements.

WEARING PARTS

Because Coffin's wearing parts are either threaded or slip fit, shrink fitting of rings and sleeves is not required, facilitating complete on-site maintenance. Further, because the high speed Coffin design requires only one or two stages to meet all covered hydraulic conditions, fewer wearing parts are required than with a conventional multi-staged design.

HIGH SPEED EFFICIENCY

Designed to operate at 7,000 to 9,000 RPM, more than twice the speed of conventional pumps. Coffin pumps improve overall pump and turbine efficiency by eliminating the mechincal loss inherent in reduction gears and coupled pump designs.

BUILT IN CONTROLS

To optimize efficiency, Coffin controls feature either constant or differential pressure regulation. Other types of remote actuator controls are available to meet customer requirements. Built in safety features include trips for excess back pressure and overspeed and a turbine casing sentinel relief valve.

MECHANICAL SEALS

Coffin's meachnical seal design virtually eliminates leakage. These newly designed seals come standard on all new Turbo Pump units. If necessary field or factory retrofitting is available.