EH Oil Purification: Keeping Turbine Control Fluid Clean, Dry and Acid-Free

6 hours ago

2 min read

At a glance. Steam turbines are governed by electro-hydraulic (EH) control systems that run on phosphate-ester fire-resistant fluid. With water and heat, this fluid forms acids that cause servo valve sticking, varnish and early fluid replacement. The Tech Inc. Fire-Resistant (EH) Oil Purification Unit removes acid, water and particles while the turbine runs. For power plants it is one of the best investments in turbine reliability.

How it works

A circulation pump draws fluid from the EH reservoir in a kidney loop.
Acid-removal vessels with ion-exchange resin or activated alumina take out acids.
A vacuum dehydration stage removes dissolved and free water.
Fine filters remove particles before the fluid returns to the reservoir.

Versions

Version	Use
Acid-removal unit	Resin vessels with fine filtration
Combined unit	Acid removal, vacuum dehydration and fine filtration
Mobile trolley	Shared between several turbines
Fixed installation	Piped permanently to one reservoir

Why it is one of the best things to happen to turbine control systems

Longer fluid life. Acid and water are removed before the fluid degrades.
Fewer servo faults. Clean fluid keeps servo valves free of particles and varnish.
No outage needed. The unit runs with the turbine in service.
One supplier. Media and elements come from the maker of the unit.

Where it is used

Thermal, nuclear and combined-cycle power plants, and any hydraulic system that uses fire-resistant fluid. For mineral oil systems see our hydraulic oil dehydrator and control oil and jacking oil HPU.