Moog has unveiled a variable-speed hydraulic pump system for injection and blow moulding machines which, it claims, can cut energy consumption by 30% or more.

The speed-controlled pump system (shown above) is based on three technologies: fixed-displacement radial piston pumps; brushless servomotors; and modular, multi-axis servodrives. The drive controls the pump motor’s torque and speed, depending on pressure and flow demand. It also stores the pump and servomotor characteristics, creating an “intelligent” system that can communicate with external systems via a fieldbus.

Moulding machines experience different loads at different parts of their operating cycles. When a machine is in the pressure-holding phase of the injection-moulding process, it needs low flow rates but high pressures, and the new system can cut energy consumption by 90% during this phase. Under full load, its performance is similar to that of a traditional system.

“Our calculations and tests show that the total cost of ownership will be lower than traditional hydraulic technologies and the payback period for the initial investment is also shorter for operators due to the impressive energy savings,” says Sheriff El Henaoui, Moog’s marketing manager for Europe.

As well as saving energy, the compact system allows the footprint of the machine to be reduced. It is also said to be quieter, with sound levels up to 9 dB(A) lower in partial-load conditions.

The speed-controlled pump system not only has advantages over the traditional hydraulic systems, but is also said to cost less to install and maintain than all-electric systems. These systems usually need to be built into the framework of the moulding machine and require complete disassembly and re-assembly for routine maintenance. The modular hydraulic system is said to be much easier and cheaper to maintain.

If required, the motor and pump can be submerged inside a hydraulic tank, thus saving space and taking advantage of the heat-dissipating fluid in tank.