The NYP Series High Viscosity Internal Gear Pump is a versatile positive displacement pump designed to meet the demanding fluid transfer requirements of the petroleum, chemical, coatings, grease, pharmaceutical, dye, and food processing industries. By offering a wide selection of wetted-part materials and seal configurations, the NYP series is adaptable to an exceptionally broad range of clean, particle-free fluids with varying viscosities and chemical properties. It is rated for viscosities from 0.02 to 100 Pa·s (20 to 100,000 cP) and operating temperatures up to 200°C. Typical media include crude oil, residual oil, heavy oil, asphalt, lubricating grease, rubber solutions, adhesives, resins, toothpaste, cosmetics, food pastes, ointments, edible oils and fats, inks, and chemical fiber slurries. (Note: This pump is designed for clean fluids only. Media containing hard solid particles or abrasive contaminants will damage the precision internal gear clearances and are not suitable.)

The pump operates on the internal gear meshing principle. The outer rotor (with internal teeth), connected directly to the motor shaft, is the driving element. It meshes with and drives the inner idler gear (with external teeth), which rotates freely on a fixed pin mounted in the front cover—both rotating in the same direction. A precision crescent-shaped divider plate, cast integrally with the front cover, permanently separates the suction port from the discharge port. As the rotors turn, the expanding tooth cavities on the suction side create a vacuum that draws fluid in; the fluid is carried around the housing within the tooth spaces and expelled as the cavities contract on the discharge side, producing a smooth, continuous, and low-pulsation flow that preserves the fluid’s original physical and chemical properties without shearing or emulsifying it.

Features & Advantages

The NYP Series pump assembly consists of inner and outer rotors, the drive shaft, pump casing, front cover, support bracket, shaft seals, and bearings. Two shaft seal configurations are available: mechanical seal, suitable for standard fluids, and packing seal, recommended for high-temperature, high-viscosity, or moderately corrosive media. A magnetic drive (fully sealed, zero-leakage) configuration is also available for applications involving toxic or hazardous fluids where even trace leakage is unacceptable; however, this option is only suitable when the fluid viscosity and required starting torque fall within the safe transmission limits of the magnetic coupling—high-viscosity applications approaching the upper rated range must be carefully evaluated to avoid magnetic slip (rotor decoupling). The standard shaft rotation is clockwise when viewed from the motor end toward the pump. The complete pump unit, consisting of the pump, motor, and baseplate, can be configured with either a bracket-coupled (indirect) or direct-coupled drive arrangement.

• Heating Jacket for Crystallizing Media: For fluids that crystallize, solidify, or become unpumpably viscous at ambient temperature—such as asphalt, wax, or certain resins—the pump head, casing, and seal chamber can all be fitted with steam heating jackets to maintain the fluid in a flowable state. The jacket is cast integrally with the pump body for superior thermal performance and eliminates the risks and failure points associated with welded jacket designs.
• Non-Shearing, Gentle Fluid Handling: The same-direction internal gear rotation transfers fluid with minimal turbulence and shear stress, making the NYP series ideal for shear-sensitive fluids such as emulsions, polymer solutions, and food products where maintaining the original fluid structure is critical.
• Built-in Overload Protection: An integrated safety valve automatically opens at 1.5 times the rated discharge pressure when the pump or downstream pipework becomes over-pressurized, creating an internal recirculation path to protect the system. The valve opening pressure can be adjusted within the allowable range. (Note: This safety valve is for emergency protection only and must not be used as a continuous pressure-reducing device.)
• Flexible Material Selection: Wetted components can be manufactured from a range of materials—including cast iron, carbon steel, and stainless steel—to match the chemical compatibility requirements of specific process fluids, enabling the NYP series to serve industries from petroleum refining to food and pharmaceutical processing.
• Compact & Reliable Design: The straightforward internal geometry results in a compact footprint, easy installation, and simple maintenance. All internal rotating components are lubricated by the process fluid during operation.