Marine Diaphragm General Pump

I. Product Overview

Marine diaphragm General pumps are the "all-rounders" of ship fluid conveyance systems, designed specifically to meet the diverse complex medium conveyance needs of ships. Through the reciprocating deformation of elastic diaphragms, they achieve negative pressure suction and pressurized discharge, and can be widely adapted to various media such as fresh water, seawater, fuel oil, lubricating oil, low-concentration chemicals, and sewage containing small amounts of impurities. This completely breaks the limitation of traditional pumps being "one pump for one purpose." Constructed with stainless steel (316L), cast iron (HT250 + anti-corrosion coating), or engineering plastic (PP + glass fiber) as the main material, and diaphragms made of oil and chemical resistant fluororubber (FKM) or perfluoroelastomer (FFKM), they are compatible with various fluid media with viscosity 20-1000cSt and solid content ≤5%. The pump body undergoes salt spray protection treatment and precision sealing, with a service life of ≥8 years in -20℃~120℃ environments. It meets IMO Ship General Pump System Specifications (MSC.473(101)) and general equipment certification requirements of classification societies such as RS, LR, ABS, and CCS, widely used in multi-scenario fluid conveyance such as fresh water supply, fuel oil delivery, bilge drainage, and deck flushing of cargo ships, oil tankers, passenger ships, fishing boats, and other vessel types.

II. Core Technologies and Material Characteristics

1.Material Selection and Performance

2.Key Technical Parameter

Flow range: 2-50m³/h, adapting to different scenario flow requirements of ships (e.g., 10-50m³/h for bilge drainage, 2-10m³/h for fuel oil delivery)

Output pressure: 0.4-2.0MPa, adjustable via rotational speed to adapt to different pipeline resistances (0.4-0.8MPa for fresh water conveyance; 0.8-1.5MPa for fuel oil/lubricating oil)

Medium compatibility: Capable of conveying fresh water, seawater, diesel, heavy oil (viscosity ≤800cSt), lubricating oil, low-concentration acids and alkalis (pH 3-11), and sewage with solid content ≤5% (particle size ≤5mm), with temperatures ranging from -20℃ to 100℃

Self-priming performance: Self-priming height ≥4m, priming time ≤40 seconds (for clean water), capable of direct startup without priming, adapting to liquid extraction from low-lying cabins of ships

Anti-clogging capability: Flow channel diameter ≥50mm (≥100mm for large-flow models). The flexible deformation of the diaphragm can wrap fiber impurities for passage, with a clogging rate 80% lower than that of centrifugal pumps3.Safety and General Design

Multi-scenario explosion protection: Motors can be optionally rated Ex d IIB T4 Gb for explosion protection (for fuel/chemical conveyance) or with ordinary protection ratings (for fresh water/sewage), adapting to hazardous areas as needed

Adaptive sealing: Diaphragms and pump covers adopt adjustable compression sealing. The sealing performance can be optimized by adjusting the sealing preload for different media (leakage ≤0.1mL/h)

Ship condition resistance: The pump body and base are connected with elastic shock absorption, capable of withstanding heel ±25°, trim ±15°, and vibration acceleration 10g, with flow attenuation ≤5%

III. Technical Advantages and Innovative Design

1. Enhanced General Adaptability

Modular diaphragm system: Diaphragms adopt a quick-release design and can be quickly replaced according to media types (fluororubber FKM for oils/chemicals; nitrile rubber NBR for water/ordinary media), with replacement time ≤15 minutes.

Wide-range flow regulation: Equipped with variable frequency motors (1.5-22kW), the flow can be steplessly adjusted within 20%-100%. The same pump can meet both "small-flow high-pressure" (e.g., fuel oil) and "large-flow low-pressure" (e.g., bilge water) requirements.

Medium-adaptive coating: 316L stainless steel flow components can be optionally coated with Teflon (0.05mm thick), improving corrosion resistance to strongly corrosive media (e.g., seawater, low-concentration salt spray) by 3 times.

2. Efficient and Stable Operation

Dual-diaphragm balanced structure: Adopts symmetrically driven main and auxiliary dual diaphragms, increasing flow by 50% compared to single-diaphragm pumps, with a pressure pulsation rate ≤2%, avoiding fatigue damage to pipelines due to pressure fluctuations.

Low-energy consumption transmission: The drive mechanism uses a combination of precision gear reduction and eccentric wheels, with a transmission efficiency ≥90%, saving 15%-20% energy compared to vane pumps of the same flow.

Intelligent monitoring integration: Optional media temperature, pressure, and flow sensors can be linked with the ship's central control system to abnormal alarm, automatic shutdown, and other protection functions.

3. Improved Maintenance Convenience

Tool-free disassembly: Pump covers, valve groups, and other components are connected with quick-opening buckles, allowing daily inspection and maintenance without special tools, which can be completed by crew members themselves.

Self-cleaning flow channels: Flow channels adopt large-curvature arc transitions (R≥20mm) to reduce media retention. Basic cleaning can be completed by passing clean water before shutdown, extending the maintenance cycle to twice that of traditional pumps.

Generalization of spare parts: The generalization rate of parts such as diaphragms and valve plates for different flow models is ≥80%, reducing the pressure of ship spare parts inventory.

IV. Typical Application Scenarios

1. Fresh Water and Seawater Systems

Passenger ship domestic water supply: 300-person passenger ships use 316L stainless steel diaphragm General pumps (flow 10-15m³/h, pressure 0.6MPa) to supply fresh water to guest rooms during the day (switching to NBR diaphragms) and can be switched to seawater for deck flushing at night (switching to FKM diaphragms), with one pump replacing two traditional pumps

Fishing boat seawater ice-making: Trawler fishing boats use cast iron diaphragm General pumps (flow 8-12m³/h, pressure 1.0MPa) to convey seawater to ice machines. The salt spray corrosion resistance of the diaphragms ensures 3000 hours of continuous operation without leakage.

2. Fuel and Lubrication Systems

Cargo ship multi-oil product conveyance: 5000-gross-ton cargo ships use variable frequency diaphragm General pumps (flow 5-10m³/h, pressure 1.2MPa). Through flow regulation, they can separately convey diesel (0.8MPa, 5m³/h) and main engine lubricating oil (1.2MPa, 3m³/h), sharing a set of pipelines to reduce modification costs.

Emergency fuel switching: When the main fuel system fails, portable aluminum alloy diaphragm General pumps (flow 2-3m³/h, pressure 0.8MPa) can be quickly connected to diesel/heavy oil emergency tanks, with hand-cranked + electric dual modes ensuring uninterrupted fuel supply.

3. Sewage and Special Fluids

Passenger ship gray water treatment: Coastal passenger ships use engineering plastic diaphragm General pumps (flow 15-20m³/h, pressure 0.6MPa) to convey bathroom/kitchen gray water to treatment devices. The plastic material prevents corrosion from cleaning agents, and the anti-clogging design deals with hair and food residues.

Research vessel sample conveyance: Ocean-going research vessels use 316L coated diaphragm pumps (flow 1-3m³/h, pressure 0.5MPa) to convey seawater samples (containing plankton) to water quality analyzers. The low shear force avoids damaging sample components, ensuring detection accuracy.

4. Emergency Multi-Scenarios

Post-collision emergency drainage: When a ship collides and takes in water, large-flow diaphragm General pumps (50m³/h, pressure 1.0MPa) quickly switch to sewage mode to pump bilge water (containing sediment and oil), cooperating with plugging equipment to slow down sinking.

Fire emergency water supply: In case of initial engine room fires, diaphragm pumps draw water from fresh water tanks/seawater valves to fire hydrants (flow 20-30m³/h, pressure 0.8MPa), replacing special fire pumps for temporary emergency use.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Core media: Select base materials based on the most frequently conveyed media (cast iron/316L for water; 316L+FKM for oils/chemicals)

Flow and pressure matching: Configure according to "maximum demand ×1.2". For example, if a ship has a maximum oil demand of 5m³/h (1.0MPa) and a maximum drainage volume of 20m³/h (0.6MPa), a 10m³/h, 1.2MPa model is recommended (variable frequency adjustment can meet both requirements)

Special needs: Choose large-channel models for high solid content; 316L + Teflon for strong corrosion; modular diaphragm design for frequent media switching

2. Maintenance Points

Daily inspection: Check inlet and outlet pressure (fluctuation ≤±0.1MPa) and leaks daily; switch between different media modes to run for 10 minutes weekly to ensure the switching mechanism is flexible.

Regular maintenance: Replace diaphragms (FKM service life 8000 hours/NBR 6000 hours) and clean valve groups every 2000 hours; rinse flow channels with clean water quarterly to remove media residues.

Media switching maintenance: Rinse the pump chamber with diesel before switching from oil to water; rinse with clean water 3 times before switching from corrosive media to ordinary media.

3. Compliance Inspection

Annual classification society inspection to verify flow stability (deviation ≤±10%), sealing performance, and explosion-proof safety (if applicable) under different media.

Meet IMO requirements for marine General pumps, ensuring that they can start and reach rated flow within 3 minutes in any media mode.

VI. Compliance and Certification

International standards: Complies with ISO 15749 Marine Diaphragm Pumps and IMO General Requirements for Ship Machinery (MSC.253(83))

Classification society certifications: Obtained type approval for General diaphragm pumps from RS, LR, ABS, and CCS (including multi-media cycle tests, vibration and tilt tests)

Environmental requirements: Compatible with oil-water separators and sewage treatment devices, with discharged water quality meeting MARPOL Annex I/IV requirements