Viking HL495 1 1/2″ NPT Rotary Gear Pump

Viking HL495 1 1/2″ NPT Rotary Gear Pump

The Viking HL495 is a heavy-duty internal rotary gear pump designed for continuous industrial and marine fluid handling. Utilizing Viking’s proven positive displacement principle, this unit features a rotor-within-a-rotor design with only two moving parts, ensuring smooth, non-pulsating fluid delivery even under high-viscosity conditions. Built with a robust cast iron housing and precision-machined internal gears, the HL495 handles demanding lubrication, fuel transfer, and chemical processing tasks with exceptional reliability.

Model Details

• Manufacturer Part Number (MPN): HL495 (Standard configuration with NPT connections)
• Common Assembly Cross-References: Series 495, 4195 High-Speed Units

Compatibility

• Compatible Drive Systems: Direct coupled or V-belt driven via standard industrial electric motors (typically 3 HP to 5 HP at 1750 RPM depending on fluid viscosity).
• System Integration: Fully compatible with standard ANSI/NPT threaded pipe configurations found in ship engine rooms, fuel skid packages, and industrial process lines.
• Fluid Compatibility: Lube oils, heavy fuel oils (HFO), marine diesel oil (MDO), asphalt, resins, polymers, and non-corrosive viscous industrial chemicals.

Key Features

1. Positive Displacement Operation: Delivers a constant, predictable volumetric output directly proportional to shaft speed, unaffected by pressure variations.
2. Built-In Safety Relief Valve: Integrated internal relief valve protects downstream piping and pump components from over-pressurization.
3. Self-Priming Capability: Excellent dry-lift characteristics allow the pump to clear suction lines rapidly during startup.
4. Robust Cast Iron Construction: Heavy-walled structural casing designed to withstand demanding thermal and mechanical operating stresses.
5. Low Maintenance Design: Features a simple, accessible gear assembly layout that minimizes downtime during scheduled overhauls.

Applications

• Marine engine room fuel oil transfer and booster skids
• Lube oil circulation and filtration loops
• Bulk chemical and petroleum product terminal distribution
• Industrial hydraulic and cooling fluid management systems
• Resin, adhesive, and viscous polymer processing lines

Engineer Expert’s Guide

• Viscosity Management: When pumping high-viscosity fluids (above 500 SSU), ensure proper motor sizing and reduce pump operating speeds to prevent cavitation and starved suction conditions. Always verify net positive suction head available (NPSHa).
• Relief Valve Setting: During initial commissioning on marine skids, calibrate the internal relief valve approximately 10% above your maximum operating pressure to safeguard pipeline integrity without causing nuisance trips.
• Dry Running Prohibition: Never run the HL495 dry for extended periods. Lubrication from the pumped fluid is critical to prevent scoring on internal bushings and idler pins.

Frequently Asked Questions

Can the Viking HL495 handle high-temperature fluids?

Yes, standard configurations with fitted FKM elastomers handle moderate elevated temperatures, but specific high-temperature bushing upgrades are recommended for continuous operations exceeding 150°C.

Is the port orientation reversible?

The HL495 features opposite port configurations. Flow direction can be reversed by reversing the rotation of the drive motor, though internal relief valve functions must be evaluated during directional changes.

What is the recommended filtration mesh size on the suction side?

To protect the internal gear teeth from foreign particulate damage, install a coarse suction strainer (typically 40 to 60 mesh) upstream of the pump inlet.