# Twin-screw Pump
A twin-screw pump is a high-efficiency positive displacement pump. Its core components consist of a pair of intermeshing and synchronously rotating screws (drive screw and driven screw), pump casing, timing gears, shaft seals and other parts. Most screws adopt an involute or cycloid profile design, with a precisely controlled meshing clearance of **0.05–0.15 mm**, which ensures sealing performance while reducing operational wear.
Its working principle is that closed chambers are formed as the screws rotate. These chambers move axially and smoothly from the suction port to the discharge port, achieving **pulse-free delivery** by continuously displacing the fluid, effectively avoiding damage to shear-sensitive media.
Thanks to its unique structural design, the pump offers significant advantages:
- Strong self-priming capability, with a maximum suction lift of **8 meters**, enabling startup without additional priming.
- Extensive media adaptability, handling fluids with viscosities ranging from **1 to 10⁶ mm²/s**, including clean fluids, fluids with micro-particles (diameter ≤ 0.2 mm), and weakly corrosive media.
- Low shear force during operation, with noise controlled below **75 dB**.
- Equipped with external bearings and an independent lubrication system, allowing safe handling of non-lubricating media and extending service life by **30%** compared with conventional screw pumps.
With these advantages, the twin-screw pump occupies an important position in complex working conditions across various industries, featuring extensive and highly targeted applications. In the **petroleum and petrochemical industry**, it serves as core equipment for crude oil extraction, refining, storage and transportation. It can stably convey high-viscosity crude oil, heavy oil and lubricating oil, adapt to various chemical additives, resist the corrosiveness and high temperature of media, and ensure continuous production. In the **food processing industry**, its characteristics of low shear force and pulse-free delivery are particularly critical. It can safely transport shear-sensitive and high-viscosity materials such as syrup, dairy products, jam and chocolate paste, avoiding damage to the original quality and taste of materials and complying with food hygiene standards. In the **marine and navigation field**, the twin-screw pump can adapt to special working conditions such as offshore turbulence and large fluctuations in temperature and humidity. It can be used for the delivery of ship fuel and lubricating oil, as well as the treatment of cabin sewage and ballast water, providing reliable support for ship navigation with stable performance. In the **environmental protection industry**, relying on its adaptability to media containing particles, the pump efficiently conveys municipal sludge, industrial wastewater and various environmental treatment agents. It can maintain a stable flow even when dealing with fluids with high impurities and high viscosity, supporting the orderly progress of pollution control. Extra attention shall be paid to operation and selection to ensure long-term stable performance of the equipment. During operation, regularly disassemble and inspect the meshing clearance and wear condition of the screws, and replace aged shaft seals and sealing components in a timely manner. **Dry running is strictly prohibited** to avoid damage caused by severe friction between the screws and the pump casing. Meanwhile, the particle size of the medium shall be strictly controlled within the specified range of below 0.2 mm. During model selection, accurately match the working condition parameters. Select the appropriate profile, material and structure based on medium viscosity, temperature, flow rate and working pressure. For example, stainless steel can be used for corrosive media, and high-temperature resistant sealing components shall be equipped for high-temperature working conditions, so as to maximize the performance of the equipment.
