Application Scenarios:

The D662-4766 is optimized for heavy-duty industrial closed-loop systems where high flow rates must be combined with high precision. It is extensively used in plastic injection molding machines (for injection and velocity control), large die-casting machines, metal forming presses, and high-capacity fatigue testing rigs. The ServoJet® pilot stage is particularly advantageous in these environments because it creates higher spool-driving forces than traditional nozzle-flapper designs, ensuring reliable operation even in the presence of minor fluid contamination or high flow-induced forces.

Precautions for Use:

1. Fluid Cleanliness: While the ServoJet® design is more “dirt-tolerant” than other pilot stages, you should maintain a hydraulic fluid cleanliness of ISO 4406 17/14/11 or better to maximize the life of the metering edges.

2. Filtration: A high-pressure filter with a rating of $\beta_{10} \geq 75$ must be installed directly upstream of the valve. The filter should not have a bypass valve to prevent unfiltered oil from entering the pilot stage during a pressure surge or cold start.

3. Pilot Pressure: Ensure that the pilot supply pressure is stable and at least 25 bar (360 psi) above the return pressure. Insufficient pilot pressure will cause sluggish response or failure of the spool to reach its full stroke.

4. Electrical Grounding: Use shielded cables for all command and feedback signals. The shield must be connected to the mating connector housing to comply with EMC regulations and to shield the integrated electronics from electrical noise.

5. Flushing Procedure: Never use the D662-4766 to flush a new or dirty hydraulic system. Use a flushing plate to clean the piping thoroughly before installing the servo valve to avoid permanent damage from initial system debris.

6. Manifold Flatness: The manifold mounting surface must be flat within 0.01 mm per 100 mm. An uneven surface can cause the valve body to warp when bolted, potentially leading to spool friction or sticking.