Screw Pump with Loose Pusher: Design and Functionality A screw pump with a loose pusher is a specialized type of positive displacement pump designed for handling viscous, abrasive, or shear-sensitive fluids. This configuration is particularly effective in applications requiring steady flow with minimal pulsation, such as in oil and gas, wastewater treatment, or food processing industries. Design Features The pump consists of a single or multiple helical screws (rotors) that rotate within a stator, typically made of elastomeric material to ensure a tight seal. The "loose pusher" refers to a non-fixed, floating component—often a secondary screw or pusher element—that moves axially within the pump housing. Unlike rigidly fixed screws, the loose pusher adjusts dynamically to maintain optimal contact with the stator, compensating for wear or variations in fluid viscosity. Key components include: 1. Rotor (Screw): The primary rotating element that drives fluid movement. 2. Stator: A stationary liner with a helical cavity that interacts with the rotor to create pumping action. 3. Loose Pusher: A floating element that enhances sealing and compensates for wear, reducing leakage and improving efficiency. 4. Inlet/Outlet Ports: Positioned to allow smooth fluid entry and discharge. Working Principle As the rotor turns, cavities form between the screw threads and the stator, trapping fluid and moving it axially from the suction side to the discharge side. The loose pusher dynamically adjusts its position, ensuring consistent sealing pressure against the stator. This adaptability minimizes internal slippage, even as the stator wears over time, maintaining volumetric efficiency. Advantages - Self-Compensating: The loose pusher reduces the need for frequent manual adjustments, lowering maintenance costs. - Handles Viscous Fluids: Ideal for thick, abrasive, or non-Newtonian fluids. - Low Pulsation: Provides smooth, continuous flow, reducing vibration and stress on piping systems. - Durability: The design extends service life by accommodating wear without significant performance loss. Applications Common uses include: - Transferring crude oil, sludge, or multiphase fluids. - Pumping high-viscosity materials like adhesives, syrups, or polymers. - Industrial processes requiring gentle handling of shear-sensitive media. Conclusion The screw pump with a loose pusher combines reliability with adaptability, making it a robust solution for challenging pumping tasks. Its ability to self-adopt to wear and varying operational conditions ensures long-term efficiency, reducing downtime and operational costs.