Rotating oil union with centerline mounted displacement probe, system for measuring displacement of regulation system of variable pitch axial fan and method thereof

A system for measuring displacement of a regulation system for a variable pitch axial fan, comprising:

• a hub including a plurality of adjustable pitch fan blades;
• a hydraulic cylinder connected to the hub;
• a piston disposed within the hydraulic cylinder, the piston coupled to a piston shaft, the piston axially movable with respect to the hub, the piston shaft coupled at one end to an actuation assembly for adjusting the pitch of the plurality of adjustable pitch fan blades in response to an axial movement of the piston;
• and
• a rotating oil union having a housing and an interior element, the interior element coupled to the hydraulic cylinder so that rotation of the cylinder and the hub causes rotation of the interior element, the rotating oil union further comprising a static housing and a central probe fixed to the static housing,
• wherein the central probe extends through respective openings in the interior element, the hydraulic cylinder, and the piston,
• wherein the central probe is configured to sense an axial position of the piston and to generate a signal representative of said axial position, and
• wherein the piston is configured to axially move relative to a distal end portion of the central probe.

A method for measuring displacement system of a regulation system for a variable pitch axial fan, comprising:

• receiving, at a monitoring system, a signal from a central probe mounted in a rotating oil union, the signal representative of an axial position of a piston disposed about the central probe;
• and
• determining, at the monitoring system, a pitch of a plurality of fan blades,
• wherein the pitch of the plurality of fan blades is related to the axial position of the piston,
• wherein the central probe is mounted along a central axis of the variable pitch axial fan, and
• wherein the piston is configured to axially move relative to a distal end portion of the central probe.