Marine Diaphragm Lubricating Oil Pump

I. Product Overview

Marine diaphragm lubricating oil pumps are the "flexible conveying core" of ship power equipment lubrication systems, designed specifically to convey high-viscosity lubricating oils (such as gear oil and hydraulic oil). Through the reciprocating deformation of elastic diaphragms to create volume changes, they achieve negative pressure oil suction and pressurized conveyance, fundamentally solving the problems of particle contamination from metal friction and conveyance in traditional gear pumps when handling high-viscosity media. Constructed with stainless steel (316L), cast iron (HT250 + wear-resistant coating), or aluminum alloy (ADC12 + anodization) as the main material, and diaphragms made of oil-resistant nitrile rubber (NBR) or fluororubber (FKM), they are compatible with mineral and synthetic lubricating oils (containing trace additives) with viscosity 30-1000cSt. The pump body undergoes anti-corrosion treatment and precision sealing, with a service life of ≥8 years in -20℃~120℃ environments. It meets IMO Ship Machinery Lubrication System Specifications (MSC.389(94)) and lubrication equipment certification requirements of classification societies such as RS, LR, ABS, and CCS, widely used in forced lubrication systems of key equipment like cargo ship main engines, oil tanker gearboxes, and fishing boat diesel engines.

II. Core Technologies and Material Characteristics

1.Material Selection and Performance

2.Key Technical Parameters

Flow range: 1-15L/min, suitable for equipment power 500-10000kW (e.g., 3000kW main engines require flow ≥5L/min)

Output pressure: 0.5-2.0MPa, meeting oil film formation requirements of friction pairs such as bearings and gears (oil film thickness ≥8μm)

Medium compatibility: Capable of conveying No.30 machine oil, No.46 anti-wear hydraulic oil, No.150 gear oil, and No.220 extreme pressure gear oil, with temperatures ranging from -20℃ to 120℃ and viscosity 30-1000cSt

Self-priming performance: Self-priming height ≥1.5m, priming time ≤40 seconds (for No.46 hydraulic oil), capable of directly drawing oil from low-level lubricating oil tanks without manual filling

Conveyance stability: Flow pulsation rate ≤3%, outlet pressure fluctuation ≤±0.05MPa, ensuring uniform and uninterrupted lubrication of friction pairs

3.Safety and Protection Design

Overload protection: Equipped with pressure relays, automatically shutting down and alarming when pipeline pressure exceeds 1.2 times the rated value due to blockage, avoiding pump overload damage

Dry-running protection: Integrates liquid level sensors, immediately shutting down when lubricating oil is sucked dry (dry-running tolerance ≤3 minutes) to prevent diaphragm wear from oil shortage

Explosion-proof certification: Motors adopt Ex d IIB T4 Gb explosion-proof grade, suitable for Zone 2 hazardous areas in engine rooms to prevent ignition of oil-gas mixtures

III. Technical Advantages and Innovative Design

1. High-Viscosity Media Conveyance Capacity

Variable-diameter flow channel design: Suction section flow channel diameter φ25mm, pressure section gradually shrinking to φ15mm. By changing the flow channel cross-section, flow velocity is increased (up to 2m/s), improving conveyance capacity of 1000cSt high-viscosity gear oil by 40% compared to traditional diaphragm pumps.

Diaphragm material optimization: Fluororubber (FKM) diaphragms adopt "fabric reinforcement + vulcanization strengthening" technology, with tensile strength ≥15MPa. They operate continuously in 120℃ high-temperature oil for 5000 hours without cracking, with a service life twice that of ordinary nitrile rubber.

Heating auxiliary system: For low-temperature high-viscosity scenarios, the pump body integrates an electric heating jacket (500W power), which can heat lubricating oil from -20℃ to 30℃ (viscosity reduced to below 200cSt) to ensure smooth low-temperature startup.

2. Operational Stability Enhancement

Dual-diaphragm synchronous drive: Adopts symmetric arrangement of main and auxiliary dual diaphragms, realizing alternating oil suction and discharge through eccentric wheel linkage. Flow rate is 50% higher than single-diaphragm pumps, with pressure pulsation rate ≤2% to avoid noise from pipeline vibration.

Precision valve group design: Suction and discharge valves use conical sealing structures (sealing surface roughness Ra≤0.8μm) with response time ≤0.1 seconds, ensuring no lag in opening and closing in high-viscosity media for stable flow.

Low-friction transmission: Drive components use bronze bushings (friction coefficient ≤0.08) with food-grade grease, achieving transmission efficiency ≥90% and reducing energy consumption by 15% compared to traditional steel bushings.

3. Ship Operating Condition Adaptability

Modular structure: Wear parts such as diaphragms and valve groups use snap-on installation, reducing replacement time to ≤20 minutes, 60% shorter than traditional pumps.

Impact resistance: Pump body and base are connected via rubber shock pads, capable of withstanding ship heel ±20° and trim ±10° with flow attenuation ≤5%.

Compact design: Single unit weight ≤35kg (5L/min model), 30% smaller in volume than gear pumps of the same flow, suitable for installation in narrow engine room spaces.

IV. Typical Application Scenarios

1. Main Engine and Gearbox Lubrication

Cargo ship main engine bearing lubrication: 10000kW cargo ship main engines use 316L stainless steel diaphragm lubricating oil pumps (flow 8-10L/min, pressure 1.6MPa) to convey No.46 anti-wear hydraulic oil to crankshaft main bearings. The pressure compensation function maintains an oil film thickness ≥10μm, ensuring bearing temperature ≤80℃ during continuous main engine operation.

Oil tanker reduction gearbox lubrication: 5000kW gearboxes are equipped with cast iron diaphragm pumps (flow 5-6L/min, pressure 1.2MPa) to convey No.150 gear oil to meshing tooth surfaces. The dual-diaphragm design ensures flow pulsation rate ≤1%, reducing tooth surface wear from uneven lubrication.

2. Emergency and Auxiliary Lubrication

Fishing boat diesel engine emergency oil supply: When the main lubrication pump fails during coastal fishing boat navigation, portable aluminum alloy diaphragm pumps (flow 2-3L/min, pressure 0.8MPa) connect to backup oil tanks via quick connectors. With dual hand-crank + electric drive modes, they can maintain diesel engine idle operation for 2 hours (consuming approximately 5L oil), buying time for return voyage.

Windlass hydraulic system oil replenishment: When port workboat windlass hydraulic oil is insufficient, stainless steel diaphragm pumps (flow 1-2L/min, pressure 1.0MPa) replenish No.68 hydraulic oil to hydraulic oil tanks. The precision valve group design ensures no air bubbles are mixed during replenishment.

3. Extreme Environment Adaptation

Polar ship low-temperature lubrication: -20℃ ice zone workboats use 316L diaphragm pumps with heating jackets (flow 3-4L/min) to heat No.220 gear oil from -15℃ to 40℃ (viscosity reduced to 300cSt), providing stable lubrication for steering gearboxes with no pump body ice blockage.

Tropical high-temperature lubrication: In 45℃ engine room environments, fluororubber diaphragm pumps (flow 6-8L/min) convey No.100 high-temperature lubricating oil to turbochargers. The diaphragm's temperature resistance ensures intact sealing when outlet oil temperature reaches 90℃.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Equipment type: 316L stainless steel pumps for main engines and large gearboxes; cast iron pumps for auxiliary machines and inland equipment; aluminum alloy pumps for emergency mobile scenarios

Flow calculation: Configure 1.2 times the total oil consumption of equipment lubrication points; e.g., a gearbox consuming 10L oil per hour requires flow ≥2L/min (based on 5 hours of continuous operation)

Viscosity adaptation: Standard models for 30-500cSt; heating models for 500-1000cSt; heating-assisted models mandatory for low temperatures (≤-10℃)

2. Maintenance Points

Daily inspection: Monitor outlet pressure (fluctuation ≤±0.05MPa) and diaphragm bulging every 200 hours; manually rotate weekly to check flexibility

Regular maintenance: Replace diaphragms (NBR service life 8000 hours/FKM 15000 hours) every 1000 hours; clean oil suction filters and apply oil-resistant grease to transmission parts

Seasonal maintenance: Check heating jacket performance (heating rate ≥5℃/min) before winter; clean pump body heat sinks in summer to ensure smooth heat dissipation in high-temperature environments

3. Compliance Inspection

Annual classification society inspection focusing on verifying high-viscosity oil conveyance capacity (flow attenuation ≤10% for 1000cSt) and explosion-proof performance

Meets IMO requirements for ship machinery lubrication systems; compatibility with main engines, gearboxes, and other equipment must pass factory joint testing

VI. Compliance and Certification

International standards: Complies with ISO 12922 Ship Lubricating Oil Pump Performance Specifications and IMO MSC.389(94) Guidelines for Ship Machinery Lubrication Systems

Classification society certifications: Obtained type approval for diaphragm lubricating oil pumps from RS, LR, ABS, and CCS (including 1000-hour high-temperature oil circulation tests)

Material compliance: Flow components meet ASTM B584 (bronze) and ASTM A240 (stainless steel) standards, with proven compatibility with lubricating oils