Marine Stainless Steel Screw Pump

I. Product Overview

The marine stainless steel screw pump is a core fluid transfer equipment in the ship's power and auxiliary systems, adopting the positive displacement working principle of multi-screw meshing rotation. Through the volume change of the cavity formed by the screw and the pump sleeve, it realizes the continuous, stable and low-pulsation transfer of various media such as fuel oil, lubricating oil, seawater and chemical additives. The core advantages of the product focus on the excellent corrosion resistance, wear resistance and high mechanical strength of stainless steel materials, which can effectively resist the erosion of sulfur-containing fuel, seawater salt spray and harsh marine environment. At the same time, it has the characteristics of compact structure, stable operation, strong self-priming capacity, good adaptability to high-viscosity and impurity-containing media, and low noise. It is a key equipment in core scenarios such as ship main engine fuel supply, lubricating oil circulation, seawater cooling, ballast water transfer and chemical additive injection. Key flow-through components (rotor, stator, pump body, pump cover) are made of high-quality stainless steel materials, and seals are made of fluororubber (FKM) or perfluoroether rubber (FFKM). The pump is suitable for media temperature ranging from -20℃ to 180℃, can transfer media with viscosity ≤5000cSt, and has a service life of ≥12 years. It fully complies with IMO "Code for the Safety of Ship Machinery Systems" (MSC.385(94)), ISO 15749 Marine Positive Displacement Pump Standard and GB/T 10832 Marine Pump Technical Requirements, and has obtained type approval from mainstream classification societies such as CCS, LR, ABS and DNV. It is widely used in the fluid transfer systems of various ships such as cargo ships, oil tankers, passenger ships, engineering ships, offshore platforms and ocean-going research vessels.

II. Core Technology

2.1 Key Technical Parameters

Flow Range: 5-100m³/h, graded and adapted according to screw diameter (30-120mm) and rotation speed (300-1500r/min). The flow pulsation rate under rated working conditions is ≤1%, ensuring ultra-stable transfer.

Head Range: 20-200m, which can meet various head requirements such as main engine fuel supply (50-100m), seawater cooling system circulation (30-60m), ballast water transfer (80-150m) and high-pressure additive injection (150-200m).

Medium Adaptability: Suitable for media such as 0#/-10#/-20# diesel oil, high-sulfur heavy fuel oil (HFO), residual oil, 46-220# lubricating oil, seawater, fresh water and chemical additives (such as corrosion inhibitors, antifreeze). It can withstand impurities with solid content ≤2% (particle size ≤1.0mm) and is suitable for media viscosity of 1-5000cSt.

Rotation Speed Range: 300-1500r/min, which can be directly linked with ship diesel engines, generators and frequency converters for driving. Most models support stepless frequency conversion speed regulation to achieve precise flow control.

Self-priming Performance: Self-priming height ≥5.0m (for diesel oil), oil absorption time ≤50 seconds. No priming is required for startup, and liquid can be directly absorbed from low-level storage tanks, adapting to the layout characteristics of ship cabins.

Operation Precision: Screw meshing clearance ≤0.03mm, volumetric efficiency ≥96%, noise ≤70dB(A) under rated working conditions, and vibration acceleration ≤2.5m/s², effectively reducing the impact on the ship's hull structure.

2.2 Safety Protection Design

Pressure Protection: Equipped with a full-range safety valve and pressure sensor. When the system pressure exceeds 1.2 times the rated pressure, the safety valve automatically opens to release pressure, and the sensor sends an alarm signal to avoid overpressure damage to the pump body and pipeline.

Sealing Enhancement: Adopts a three-level sealing structure (mechanical seal + lip seal + O-ring). The mating surface of the mechanical seal is silicon carbide-silicon nitride, which has excellent resistance to high temperature, high pressure and medium erosion. The leakage rate is ≤0.005mL/h, ensuring no pollution to the marine environment.

Vibration and Shock Resistance: The pump body and base adopt integral casting and stiffener design, combined with high-elasticity shock-absorbing pads. It can withstand ship heeling ±35°, trimming ±25° and vibration acceleration of 20g, ensuring stable operation under severe sea conditions.

Explosion-proof and Corrosion-resistant: The fuel transfer scenario is equipped with Ex d IIB T5 Gb explosion-proof motor as standard, which is suitable for the ship's Zone 1/2 hazardous areas; the outer surface of the pump body is treated with anti-corrosion coating, and the internal stainless steel components have double anti-corrosion protection, adapting to the harsh marine atmospheric environment.

Comprehensive Monitoring and Protection: Equipped with motor overload protector, pump body temperature sensor, medium leakage detector and bearing temperature monitor. When abnormal conditions such as overload, over-temperature, leakage and bearing failure occur, it will automatically shut down and alarm, realizing all-round protection of the pump body and system.

III. Technical Advantages and Innovative Design

3.1 Enhancement of Exclusive Advantages of Stainless Steel

Excellent Corrosion and Wear Resistance: The 316L and duplex stainless steel flow-through components have excellent resistance to pitting corrosion, crevice corrosion and stress corrosion. No rust occurs in 2000-hour salt spray test, and no obvious wear occurs in 8000-hour high-sulfur fuel transfer test. The service life is increased by 100% compared with ordinary carbon steel screw pumps, which greatly reduces the ship's operation and maintenance costs.

High-purity and Pollution-free Transfer: The surface of stainless steel components is precision polished with roughness Ra ≤0.8μm, eliminating the risk of rust shedding and material peeling. It can avoid medium contamination by impurities, ensure the cleanliness of fuel oil and lubricating oil, and protect the normal operation of ship engines and precision components.

Wide Temperature Adaptability: Stainless steel materials maintain stable mechanical properties in the temperature range of -20℃ to 180℃, with no brittle fracture at low temperature and no deformation at high temperature. It is suitable for both cold polar sea areas and high-temperature fuel preheating transfer scenarios.

3.2 Optimization of Efficient and Stable Transfer

High-precision Screw Design: Adopts five-axis linkage precision machining to manufacture involute tooth profile screws with precise meshing. The screw surface is treated with plasma nitriding, and the hardness is ≥HRC62, which improves wear resistance and ensures long-term stable volumetric efficiency.

Adaptability to High Viscosity and Impurities: The optimized pitch and cavity structure can stably transfer high-temperature and high-viscosity media such as heavy oil and residual oil with viscosity up to 5000cSt; the large flow channel design can pass small particle impurities, avoiding blockage and reducing maintenance frequency.

Low Energy Consumption Operation: The smooth meshing of multiple screws reduces internal friction loss. Under the same flow and head conditions, the energy consumption is reduced by 15%-20% compared with traditional gear pumps, which conforms to the development trend of ship energy conservation and emission reduction.

3.3 Convenient Operation and Maintenance

Modular Integrated Design: Core components such as screw rotor, stator and seal assembly adopt modular design, which can be disassembled and replaced from the front end without disassembling the entire pipeline and motor. The maintenance time is ≤30 minutes, which greatly improves maintenance efficiency.

Intelligent Remote Monitoring: Equipped with an intelligent control module, it can realize real-time monitoring of parameters such as flow, pressure and temperature. The data is synchronized to the ship's central control system, supporting remote operation, fault diagnosis and predictive maintenance.

Generalization of Spare Parts: The generalization rate of spare parts for different flow models is high (≥92%), such as seals, bearings, universal joints, etc., which reduces the pressure of ship spare parts inventory and the cost of spare parts reserve.

3.4 Multi-scenario Adaptability

Multi-medium Universality: By replacing stators and seals of different materials, it can be quickly adapted to the transfer of various media such as fuel oil, lubricating oil, seawater and chemical additives, realizing "one pump for multiple uses" and reducing the number of ship pump configurations.

Diversified Installation and Driving Methods: Supports horizontal, vertical and flange-mounted installation methods, adapting to the limited space of ship cabins; can be matched with motor drive, diesel engine direct drive, hydraulic drive, etc., to meet the needs of different power sources of ships.

Customized Design: Can provide customized solutions according to the special needs of ships (such as polar low temperature, offshore high corrosion, deep-sea operation, etc.), including low-temperature heat preservation, enhanced corrosion resistance, deep-sea pressure-resistant structure, etc.

IV. Typical Application Scenarios

4.1 Main Engine Fuel Supply System

Main Engine Fuel Supply of Ocean-going Cargo Ships: The 30000kW main engine of ocean-going cargo ships is equipped with 316L stainless steel three-screw pumps (flow rate 30-50m³/h, head 60-100m) to transfer high-sulfur heavy fuel oil to the main engine fuel injection system. The stable and low-pulsation transfer ensures uniform combustion of the main engine, and the stainless steel material resists the erosion of high-sulfur fuel, with a continuous operation life of ≥10000 hours.

Fuel Supply of Offshore Platform Power Units: The power units of offshore platforms adopt duplex stainless steel screw pumps (flow rate 20-30m³/h, head 80-120m) as fuel supply equipment, which resist the harsh marine atmospheric environment and seawater erosion, and can operate stably for a long time under severe sea conditions, ensuring continuous power supply of the platform.

4.2 Lubricating Oil and Cooling System

Lubricating Oil Circulation of Ship Auxiliary Engines: The lubricating oil system of auxiliary engines of large oil tankers adopts 316L stainless steel screw pumps (flow rate 10-20m³/h, head 30-50m) for lubricating oil circulation and filtration. High-purity transfer avoids contamination of lubricating oil by impurities, reduces wear of auxiliary engine components, and extends the service life of auxiliary engines.

Seawater Cooling System Circulation: Passenger ships adopt duplex stainless steel screw pumps (flow rate 50-80m³/h, head 40-70m) for seawater cooling system circulation, which have excellent seawater corrosion resistance, no scaling in the flow channel, and ensure the cooling effect of ship air conditioning, power and other systems.

4.3 Ballast Water and Ship Water Transfer

Ship Ballast Water Transfer: Container ships adopt 316L stainless steel screw pumps (flow rate 60-100m³/h, head 80-150m) for ballast water transfer. The large-flow and high-head design can quickly complete the injection and discharge of ballast water, and the corrosion resistance of stainless steel ensures long-term stable operation in the seawater environment.

Fresh Water and Domestic Water Supply: Ocean-going research vessels adopt 316L stainless steel screw pumps (flow rate 5-15m³/h, head 20-40m) for fresh water storage and domestic water supply. The stainless steel material is hygienic and non-toxic, meeting the requirements of drinking water quality, and the stable transfer ensures stable water pressure.

4.4 Chemical Additive Injection and Special Medium Transfer

Fuel Additive Injection: Chemical tankers adopt duplex stainless steel screw pumps (flow rate 1-5m³/h, head 150-200m) for high-pressure injection of fuel additives (such as desulfurizers, combustion improvers). Precise flow control ensures accurate proportion of additives, and corrosion resistance adapts to the chemical properties of additives.