Principle of Internal Gear Pumps

An internal gear pump uses a large outer driving gear (rotor) and a smaller offset driven inner gear (idler) inside a pump casing. As the rotor turns, cavities between the driver and idler gears open to draw liquid into the pump, as it rotates, the cavities progressively reduces to displace the liquid toward the discharge. This continuous, enclosed movement, minimises slip, provides smooth accurate and repeatable flow. 

Why Choose a Varisco Internal Gear Pump?  

• Low pulsation and steady flow: Protects downstream equipment and improves accuracy.  
• Excellent for viscous media: Handles oils, polymers, resins, adhesives, bitumen, paints, chocolate (EC 1935/2004 certified Choco series), and more with high volumetric efficiency.  
• Gentle on product: Low shear helps preserve fluid integrity (e.g., additives, food-grade products).  
• Self-priming capability: Rapid self-priming ability offering high degree of vacuum.  
• Bidirectional operation: Reversible flow when required (with appropriate drive/control).  
• Wide temperature window: Suitable for cold-service and high-temperature duties with heating jackets and appropriate sealing.  
• Robust, serviceable design: Replaceable wear components and easy maintenance helps reduce lifecycle costs.  

Typical Applications  

• Chemicals & Petrochemicals: Polymers, monomers, additives, sealants, lubricants, waxes.  
• Energy & Asphalt: Bitumen, heavy fuel oils, thermal insulation, pitch and tar.  
• Paints & Coatings: Resins, printing ink, lacquers, additives, solvents (with appropriate materials).  
• Food & Beverage: Glucose, Syrups, chocolate, fats, oils (food-grade materials and sealing on request).  
• Personal Care: Surfactants, detergents, soaps, cleaning products & creams (low-shear transfer).  
• Chemicals: Acids, Alkalis, Polyols, Isocyanates and more..  
• General Industry: Hydraulic oil, gear oil, heat transfer fluids, detergents.  

Materials & Configurations  

• Pump Casing & Internals: Cast iron, ductile iron, carbon steel, hardened steel or stainless steel. Also available with MOCA 1935/2004‑certified, food‑safe materials. 
• Sealing Options: Mechanical seals (single/double), packed gland or lip seal.  
• Heating/Cooling jacket: Suitable for steam, thermal oil or hot water, available to maintain fluid temperature.  
• Mounting: Horizontal or Vertical mounting available complete with, base plate and motors/geared motors.  
• Compliance: Options for ATEX and food contact configurations (on request).  
• Surface Finishes: Hardened coatings treatments for chemical resistance or hygiene requirements.  
• API 676: Pumps to API676 are also available, for heavy chemical and industrial applications.  

Safety & Protection  

• Integral relief valves: Protect the pump from overpressure due to blocked lines or closed valves.  
• Instrumentation: Temperature sensors (PT100) for ATEX on mag-drive option and motor protection helps prevent dry run and overheating.