Constant-Wall Nitrile Stator for Screw Pump A constant-wall nitrile stator is a critical component in progressive cavity (PC) pumps, commonly known as screw pumps. These pumps are widely used in industries such as oil and gas, wastewater treatment, food processing, and chemical handling due to their ability to handle viscous, abrasive, and shear-sensitive fluids efficiently. The stator, typically made of elastomeric materials like nitrile rubber (NBR), works in tandem with a helical rotor to create sealed cavities that move fluid through the pump. Design and Functionality The constant-wall nitrile stator features a uniform wall thickness along its length, ensuring consistent performance and durability. Unlike variable-wall designs, which may have varying elastomer thicknesses, the constant-wall construction provides balanced stress distribution, reducing the risk of premature wear or deformation. The stator’s internal helical cavity matches the rotor’s geometry, forming progressive chambers that transport fluid from the suction to the discharge side with minimal pulsation. Nitrile rubber is chosen for its excellent resistance to oils, fuels, and many chemicals, making it ideal for applications involving hydrocarbons or aggressive media. Additionally, nitrile offers good mechanical properties, including abrasion resistance and flexibility, which are essential for maintaining a tight seal against the rotor. Key Advantages 1. Enhanced Durability – The uniform wall thickness minimizes localized stress, extending service life even under high-pressure or abrasive conditions. 2. Consistent Performance – A constant-wall design ensures stable flow rates and pressure output, reducing operational variability. 3. Chemical Compatibility – Nitrile rubber resists swelling and degradation when exposed to oils, greases, and many solvents. 4. Temperature Tolerance – Nitrile stators perform well in moderate temperature ranges, typically between -20°C to +100°C (-4°F to +212°F). 5. Reduced Maintenance – The robust construction lowers the frequency of replacements, improving pump uptime. Applications Constant-wall nitrile stators are commonly used in: - Oil & Gas – Transferring crude oil, drilling mud, or refined products. - Industrial Processing – Handling viscous fluids like adhesives, slurries, or paints. - Wastewater Treatment – Pumping sludge or abrasive fluids with suspended solids. - Food & Beverage – Moving edible oils, syrups, or other sanitary-grade fluids (if FDA-compliant nitrile is used). Considerations While nitrile stators offer many benefits, they may not be suitable for highly polar solvents (e.g., ketones, esters) or extreme temperatures. In such cases, alternative elastomers like FKM (fluoroelastomer) or EPDM may be preferred. Proper stator-rotor interference fit is also crucial to prevent slippage and ensure efficient pumping. Conclusion The constant-wall nitrile stator is a reliable and cost-effective solution for screw pumps, combining durability, chemical resistance, and consistent performance. Its design optimizes fluid transfer efficiency while minimizing wear, making it a preferred choice for demanding industrial applications.