MOOG D631K 294FK Servo Control Valve

MOOG D631K 294FK Servo Control Valve

The MOOG D631K 294FK is a two-stage electrohydraulic servo control valve used to control flow and direction in closed-loop industrial and marine automation systems. This unit is based on the D631 series platform, using a dry torque motor, a mechanical feedback cantilever spring and a high precision nozzle-flapper pilot stage. It has excellent dynamic responsiveness, very low hysteresis and complete reliability in continuous high pressure applications.

Model Details

• Brand: MOOG
• Product Category: Hydraulic Servo & Proportional Control Valves
• Series: D631 Series
• MPN (Manufacturer Part Number): D631K294FK (D631K-294FK)
• Condition Options: New

Technical Specifications: MOOG D631K 294FK

Key Features

1. Dry Torque Motor Design: Isolates electromagnetic components from direct hydraulic fluid contact, minimizing magnetic gap contamination risks.
2. Mechanical Feedback Loop: Utilizes a rigid cantilever spring linking the main spool directly to the pilot flapper for precise positioning accuracy.
3. High Spool Control Forces: Delivers swift correction adjustments and rapid step responses to stabilize high-inertia loads.
4. Rugged Environmental Build: IP65-rated housing configuration built to withstand harsh marine, offshore, and heavy industrial vibrations

Compatible Equipment Models

• Moog D631 and D634 Standard Controller Cards
• Industrial Hydraulic Power Units (HPUs) featuring ISO 4401-05 manifolds
• Marine Riser Tensioner Hydraulic Consoles
• Injection Molding Machinery Electrohydraulic Racks
• Heavy Industrial Steel Rolling Mills

Applications

• Marine active heave compensation and deck machinery systems
• Offshore drilling rig riser tensioning and motion control
• High-precision metal forming and die-casting presses
• Gas and steam turbine fuel control valve positioning
• Aerospace and defense simulation test rigs

Alternate Moog Identifiers: D631K-294FK, D631-294FK, D631K294, SK-D631K294

Frequently Asked Questions

What is the primary function of the MOOG D631K 294FK servo valve?

The MOOG D631K 294FK is a two-stage electrohydraulic servo valve designed to translate low-power electrical input signals into precise, high-force hydraulic fluid flow and directional control.

Can I substitute the D631K 294FK with a standard proportional valve?

While both handle fluid control, servo valves like the D631 series utilize mechanical feedback and nozzle-flapper pilot stages to provide significantly faster step responses, higher frequency response, and tighter hysteresis than standard proportional valves. Direct substitution requires verifying loop gain compatibility in your controller.

What filtration level is required to prevent premature servo valve failure?

To guarantee long operational life and prevent clogging of the fine flapper nozzles, your hydraulic system fluid must maintain an ISO 4406 cleanliness rating of at least 17/14/11,utilizing a 10 µm absolute (or better) filter rating