Parker's Abex Jet-Pipe® Servo Valves are approved for use on a range of GE 7E and 7F combustion turbines, other frame engines, and steam turbines. These valves serve as a direct replacement for your existing control valves. The Parker Abex Jet-Pipe® Valve's design contributes to longer-term controls reliability in power generation applications.
The Parker valves are designed to fail-to-center due to their "single-inlet" first stage. This feature eliminates the risk of unbalance from contamination being there is only a single source of fluid in the first stage. The hydraulic circuit incorporates a Jet-Pipe® with a larger flow path (0.008"). If particulate or other contaminants pass through the upstream filters, the larger flow path will allow contaminates to pass through the orifice without clogging the valve. If a blockage does occur, the turbine will not be damaged since the actuator controlling the valve will not fully extend or retract.
The Parker Abex Jet-Pipe® servo valves are remarkably contamination resistant, enabling particles as large as 200 microns to pass without fail. These valves are tremendously stable which can be attributed to the secondary stage spool. The spool has a larger diameter surface area on which the hydraulic pressure from the first stage acts. This creates a larger force with which to move the spool. If varnish begins to reduce the clearance between the spool and bushing – the spool will try to stick. The Abex valves increased second stage motive force helps to overcome varnish contamination issues and reduces the likelihood of a turbine trip.
Initial field testing determined Parker Jet-Pipe® servo valves will remain in service for 5-6 years. Compared to the current OEM's life cycle of 18-24 months, this increased service life reduces your preventative maintenance requirements and as a result, your life cycle costs.
The Parker Abex Jet-Pipe® servo valve's robust design results in a longer time between replacements, and increased confidence in your control system accurately controlling gas, steam, and stop/ratio valves.