Marine Stainless Steel Sewage Pump

I. Product Overview

Marine stainless steel sewage pumps are core equipment in ship sewage treatment systems, designed specifically for collecting and conveying domestic sewage, fecal water, kitchen wastewater, and engine room oily sewage. Constructed with 316L ultra-low carbon stainless steel (022Cr17Ni12Mo2) or 304 stainless steel (06Cr19Ni10) as the main material, they achieve efficient transportation of high-concentration, fiber-containing sewage through centrifugal or screw pump principles. Their working principle involves a power source (electric motor or pneumatic motor) driving a rotor to rotate, generating negative pressure to draw sewage from collection tanks, pressurize it, and convey it to treatment devices (e.g., biochemical reactors) or storage tanks after crushing and filtration, ultimately achieving compliant discharge or onshore transfer. The pump body undergoes electrolytic polishing and antibacterial passivation, with a corrosion-resistant service life of ≥10 years in salt-containing, organic-rich sewage. It meets IMO International Convention for the Prevention of Pollution from Ships (MARPOL) Annex IV and sewage system certification requirements of classification societies such as LR and ABS, and is mandatory for all manned vessels including passenger ships, cargo ships, and drilling platforms.

II. Core Technologies and Material Characteristics

1.Stainless Steel Material Selection and Performance

2.Key Technical Parameters

Flow range: 3-100m³/h, suitable for 50-5000 ship passengers (e.g., 3000-passenger cruise ships require flow ≥50m³/h)

Head coverage: 10-30m, meeting pressure requirements for conveying from sewage collection tanks to treatment devices

Medium compatibility: Capable of conveying domestic sewage, fecal water, and kitchen wastewater with solid content ≤8% (particle diameter ≤10mm) and oil content ≤5%

Crushing capacity: Built-in dual-blade crushing device, capable of chopping long fibers (e.g., towels, plastic bags) to ≤5mm, improving passability by 90%

Temperature adaptability: Operates at 0℃~60℃, capable of handling hot kitchen wastewater (≤50℃)

3.Sanitary and Anti-Pollution Design

Surface roughness of flow-through components ≤Ra0.8μm, meeting FDA food-grade hygiene standards to prevent bacterial growth (colony count ≤10CFU/cm²)

Equipped with liquid level linkage devices, automatically starting when sewage tank level ≥80% and stopping when ≤20% to prevent dry operation damage

III. Technical Advantages and Innovative Design

1. High-Concentration Sewage Treatment Capacity

Screw extrusion conveying: Adopts screw-stator structure to squeeze sewage through volume changes, reducing moisture content of sludge from 95% to 80%, with 30% higher conveying efficiency than centrifugal pumps, suitable for high-viscosity sewage.

Anti-clogging flow channel: Flow channels use bionic design (simulating intestinal curves), reducing fiber impurity entanglement by 70%, achieving clog-free operation cycles exceeding 800 hours in domestic sewage containing large amounts of hair and paper towels.

2. Corrosion Resistance and Sanitary Assurance

All-stainless steel structure: Pump body, impeller, and shaft sleeve are made of homogeneous stainless steel to avoid galvanic corrosion from contact between dissimilar metals, withstanding 2000-hour salt spray tests without rust.

Self-cleaning cavity: Automatically flushes with clean water for 30 seconds before shutdown, leaving residual sewage ≤50mL in the cavity to reduce odors and bacterial growth, meeting ship sanitary quarantine requirements.

3. Intelligent and Safe Operation

Overload protection system: Automatically shuts down when torque exceeds 1.5 times the rated value (response time ≤1 second) to prevent damage to impellers from hard impurities (e.g., coins, bones).

Remote monitoring function: Supports real-time monitoring of flow, pressure, and fault status by the ship's central control system, with remote start-stop capability, adapting to unattended engine rooms.

IV. Typical Application Scenarios

1. Domestic Sewage Treatment

Large cruise ship sewage systems: 3000-passenger cruise ships are equipped with 316L stainless steel screw sewage pumps (flow 50-80m³/h, head 25m) to crush and convey sewage from guest rooms and restaurants to biochemical treatment devices, with stable outlet pressure at 1.0±0.1MPa, meeting IMO discharge limits (BOD≤50mg/L).

Cargo ship crew sewage: 500-crew cargo ships use 304 stainless steel sewage pumps (flow 10-20m³/h) to handle fecal water and handwashing wastewater, cooperating with vacuum collection systems to reduce pipeline clogging risks.

2. Special Sewage Conveying

Kitchen wastewater treatment: Cruise ship kitchens are equipped with 316L sewage pumps with heating jackets (flow 5-15m³/h) to convey oily wastewater (50℃) to oil-water separators, with impellers resistant to oil scale adhesion, extending cleaning intervals to 3 months.

Engine room oily sewage: 316L stainless steel centrifugal pumps (flow 20-50m³/h) are used to convey engine room sewage with 5% oil content to oil-water separators, with impellers resistant to emulsified oil corrosion, achieving service life exceeding 10,000 hours.

3. Emergency and Special Scenarios

Polar ship sewage conveying: In -20℃ environments, pump bodies are insulated with electric tracing to prevent sewage freezing, with flow 10-30m³/h, providing sewage treatment support for scientific research station personnel, with start-up time ≤60 seconds.

Drilling platform sewage: Offshore platforms use explosion-proof 316L sewage pumps (Ex d IIB T4) with flow 30-60m³/h to treat domestic sewage containing trace chemicals, operating stably in high-salt spray environments.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Ship type: 316L stainless steel for ocean-going ships and high sanitary requirements; 304 stainless steel for inland ships

Sewage volume: Configure flow at 0.25m³ per person per day; e.g., 1000-person ships recommend flow ≥250m³/d (i.e., 10.4m³/h)

Medium characteristics: Models with crushing devices for large amounts of fibers; screw pumps for high-viscosity sewage; 316L material for oily sewage

2. Maintenance Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.2MPa), bearing temperature (≤70℃), and current value (≤110% of rated value) every 500 hours

Regular maintenance: Clean inlet filters monthly; inspect crushing blade wear every six months (allowable edge gap ≤1mm); replace mechanical seals (food-grade fluoroelastomer material) annually

In-depth maintenance: Disassemble and inspect every 3 years; re-passivate 316L components; test motor insulation resistance (≥50MΩ)

VI. Compliance and Certification

International standards: Complies with IMO MARPOL Annex IV and MEPC.227(64) ship domestic sewage discharge standards

Classification society certifications: Passed type approval for sewage pumps by LR, ABS, and CCS (including 1000-hour sanitary performance tests)

Environmental requirements: Compatible with sewage treatment devices, with discharged water meeting IMO G9 Guidelines' heavy metal limits (Pb≤0.5mg/L)