Bronze Rotary Gear Pump - N91

Key Features:

• Durable bronze body with a high-quality stainless steel shaft
• Standard nitrile mechanical seal, with fluoroelastomer as an optional upgrade
• Self-lubricating carbon bearings for reduced maintenance
• Convenient carbonator motor mount for easy installation

• Precision bronze spur gears for smooth operation
• Capable of withstanding up to

Handling Liquids and Operating Temperatures:
Our bronze gear pump is ideal for pumping water, oil, and mild chemicals within a pH range of 4-10. It can handle viscous liquids up to a viscosity of 300 SSU (~65 centistokes, cSt). For higher viscosity fluids, consider alternative pumps, as carbonator motors are not available for speeds below 1725 RPM (~143 revolutions per second). To preserve the pump's lifespan, avoid pumping liquids with abrasives, solids, powders, or pigments. The optimal temperature range for liquids is 32°F to 140°F (0°C to 60°C). Should you encounter more extreme temperatures, we advise consulting with our factory to ensure proper pump selection. Prevent damage by not allowing the liquid to freeze inside the pump.

Efficient Suction Lift:
To ensure immediate fluid flow and prevent dry running, prime the pump before the first start-up. While the N91 is self-priming, we recommend installing a foot valve with a strainer at the start of the suction line to keep the gear chamber ready for action. The pump can achieve a maximum suction lift of 20 feet (6.1 meters), and we suggest keeping the suction line as brief as possible for best performance.

Rotation and Relief Valve:
The relief valve is designed to relieve discharge pressure, not for metering or flow control. It activates when the discharge pressure surpasses the spring tension, preventing overheating, which can occur in 5–10 minutes if the discharge line is closed for too long.

The pump motor unit is factory-set for a clockwise shaft rotation from the shaft end unless specified otherwise. Reversing motor rotation will invert the "in" and "out" ports and require you to change the relief valve location, which is always on the discharge side for this series. The standard factory pressure setting is 50 PSIG (~3.4 bar), adjustable upward by turning the relief valve screw clockwise. For settings between 100–200 PSI (6.9–13.8 bar), you'll need to specify the high-pressure spring (N91D).

Instructions for reversing single-phase motors can be found inside the junction box cover or on the motor's nameplate.

For more information or to see how the Bronze Gear Pump N91 can be integrated into your operations, please reach out to us. Our experts are on hand to ensure you receive a pumping solution that offers efficiency, durability, and ease of use.