Upgrading an ElectraTherm 6500 to BITZER's semi-hermetic expander generator

In 2023 we upgraded an ElectraTherm 6500 to BITZER's semi-hermetic expander generator, the same expander generator design used across today's Power Modules. We'd already carried out this upgrade on a 4400. This time it was the larger machine.

Before: an open-drive expander

The original 6500 used an open-drive twin-screw expander, coupled to a separate induction generator. The expander shaft leaves the casing through a shaft seal, and over the years that seal is where leaks and working fluid losses come from.

The original open-drive expander and separate generator.

Strip-out

We removed the old expander, coupling and generator, leaving the bay clear for the new unit.

The expander bay stripped out.

The old expander and generator, removed.

Fitting the BITZER expander generator

The BITZER unit puts the twin-screw expander and the generator in one sealed housing, so there's no coupling to align and no shaft seal to leak. We fitted it into the existing frame with new pipework to suit.

The new expander generator going in, with new pipework.

Finished: the BITZER semi-hermetic expander generator in place.

Running an older ElectraTherm?

If your ElectraTherm still has an open-drive expander, talk to us about upgrading it to the BITZER expander generator.