National Oilwell 310016/94200 Hydraulic Load Control Valve Block

National Oilwell 310016/94200 Hydraulic Load Control Valve Block (NEW Surplus)

The National Oilwell (NOV) Item No. 310016/94200 is an OEM-grade hydraulic load control valve manifold block engineered specifically for heavy-duty marine, offshore, and drilling applications. Designed to integrate directly into high-pressure hydraulic hoist, luffing, and winch circuits, this manifold serves as a critical safety and motion-control junction. It houses load-holding counterbalance (overcenter) elements and pressure-relief cartridges to prevent uncontrolled runaway of suspended loads in the event of line rupture, thermal expansion, or sudden directional valve transitions.

Manufactured from high-yield ductile iron / forged alloy steel to withstand continuous dynamic pressures up to 350 bar (5,075 psi) and harsh offshore marine salt-spray atmospheres, this assembly guarantees zero internal drift, smooth metering during lowering operations, and instant positive lock-up under zero-pilot conditions.

Model Details:

• Manufacturer: National Oilwell Varco (NOV)
• Part / Item Number: 310016/94200
• Component Type: Hydraulic Motion & Load Control Manifold Block
• Condition: New Unused Surplus

Technical Details

Key Features

1. Precision Overcenter & Load Holding: Integrated pilot-operated counterbalance functionality prevents hydraulic motor cavitation and mechanical runaway during overrunning load conditions on cranes and winches.
2. Integrated Secondary Relief Protection: Provides thermal expansion relief and hydraulic shock surge attenuation downstream of line valves, protecting cylinders, drive motors, and high-pressure hose assemblies.
3. Cavity & Port Machining Accuracy: High-tolerance CNC-machined cavity ports conforming to strict SAE/ISO standards ensure leak-free cartridge sealing under severe cyclical impulse pressures.
4. Harsh marine Environment Resilience: Heavy-duty anti-corrosion exterior surface protection and phosphate/passivated internal cavities engineered to withstand offshore atmospheric salt exposure and high-humidity marine engine room conditions.
5. Positive Pilot-Ratio Dynamic Response: Optimized pilot ratio provides smooth load feathering and precise modulation without hydraulic judder or erratic system resonance across variable oil viscosities.

Valve Compatibility

• NOV Offshore & Marine Cranes: Lattice boom and box boom pedestal cranes (main hoist, whip hoist, and luffing cylinder motion blocks).
• Drilling Rig Floor Handling Machinery: Pipe-handling arms, iron roughnecks, cathead winches, and BOP handling overhead cranes.
• Deck Machinery & Mooring Systems: Constant-tension winches, anchor handling & towing winches (AHTW), oceanographic winches, and tugger winches.
• Marine Offshore A-Frames & Davits: Offshore launch and recovery systems (LARS) and tender boat handling equipment requiring static zero-leak load locking.

Part Number Cross-References

• Primary OEM Item No: 310016/94200
• Alternate OEM Representation: NOV 310016-94200 / NOV 310016 94200
• Sub-Assembly / Casting Code: 310016 (Manifold Main Machined Housing) / 94200 (Factory Cartridge Load Control Sub-Assembly)

Frequently Asked Questions

What is the primary function of the National Oilwell 310016/94200 valve block?

The 310016/94200 serves as a pilot-operated hydraulic load control and counterbalance manifold. It regulates the descent speed of heavy loads, prevents hydraulic motor cavitation during overrunning loads, and provides an immediate positive mechanical-hydraulic lock in the event of upstream supply pressure failure or hose rupture.

Can this block be directly retrofitted to other marine winch brands?

While engineered primarily for National Oilwell Varco (NOV) lifting and drilling equipment, this valve block can interface with standard open-loop or closed-loop hydraulic systems on third-party winches and cranes, provided the flow rate, pilot ratio, mounting envelope, and operating pressures match your system’s engineering criteria.

Is this unit an aftermarket copy or original NOV manufacture?

This is a genuine National Oilwell (NOV) component in new unused surplus condition. It retains genuine factory machining integrity, original internal tolerances, and OEM sealing profiles.

What hydraulic oil types are approved for use with this manifold?

It is fully compatible with standard anti-wear mineral-based hydraulic oils (HLP/HVLP conforming to DIN 51524 parts 2 and 3) in ISO VG 32, 46, and 68 grades. For offshore systems utilizing biodegradable synthetic esters (HEES), verify that the fitted FKM/Viton elastomeric seals are fully compatible with your specific oil additive package.

How do I troubleshoot erratic shuddering during crane lowering operations?

Chatter or shuddering during lowering usually stems from two factors: an unstable pilot signal caused by an un-damped pilot line, or a pilot ratio mismatch where the cracking pressure is fighting against load oscillations. Check that the pilot signal line is equipped with the specified damping orifice and verify that tank return line backpressure is under 5 bar (72 psi).