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Overview
The Graviner Mark 5 Oil Mist Detector does not passively wait for oil mist to reach its sensor — it actively draws crankcase atmosphere through its detection chamber using an internal fan assembly. This continuous active sampling is fundamental to how the MK-5 operates: the fan creates the controlled airflow that carries crankcase air through the optical measurement path, allowing the detector to continuously monitor oil mist concentration in near real-time across the engine’s operating cycle. When the fan assembly fails — through motor burnout, bearing wear, or impeller damage — the detector loses its sampling capability entirely. Without airflow through the detection chamber, the MK-5 cannot measure oil mist concentration, cannot generate a valid alarm, and is effectively non-functional as a crankcase protection device regardless of whether its optical and electronic systems remain intact.
The Fan Assembly for Graviner Mark 5 Oil Mist Detector is a refurbished replacement fan assembly unit for the Graviner MK-5 detector. The assembly — a centrifugal blower unit with integrated motor, impeller housing, and wiring harness — is the active sampling component at the core of the MK-5’s continuous crankcase atmosphere monitoring function. Replacing a failed or degraded fan assembly restores the detector’s airflow and, with it, its entire oil mist detection capability.
What sets this replacement apart from generic alternatives is component specificity and system compatibility. The MK-5 fan assembly is engineered to deliver a defined airflow rate through the detection chamber at the correct velocity for the detector’s optical measurement geometry. A substitute fan unit with different airflow characteristics — even if it physically fits — changes the residence time of sampled air in the detection chamber, which directly affects the accuracy and response time of the oil mist concentration measurement. An OEM-compatible replacement fan assembly maintains the designed airflow specification and, with it, the detector’s type-approved measurement performance.
Key Features
Centrifugal Blower Design — Continuous Active Crankcase Sampling
The fan assembly uses a centrifugal blower configuration — visible in the image as a scroll-housing impeller unit — which is well-suited to generating consistent airflow against the back-pressure of the MK-5 detection chamber and sampling tube network. Unlike axial fans, a centrifugal blower maintains more stable airflow across varying back-pressure conditions, which is important for a detector that samples through tubes of varying length depending on where the detector point is positioned relative to the crankcase sampling point. Consistent airflow is consistent measurement — and consistent measurement is reliable alarm performance.
Integrated Motor and Wiring Harness — Direct Replacement Assembly
As visible in the product image, the fan assembly is supplied as a complete unit — centrifugal impeller housing, drive motor, and wiring harness with connector — allowing direct replacement of the complete fan assembly within the MK-5 detector without requiring separate motor sourcing or harness fabrication. Assembly-level replacement simplifies the repair process: the failed unit is removed, the replacement assembly is fitted and connected using the existing harness connector, and the detector is returned to service without the additional time investment of component-level motor or harness repair.
Engineered Airflow for MK-5 Detection Chamber Geometry
The airflow rate and velocity profile generated by the MK-5 fan assembly are matched to the optical detection chamber’s dimensions and the photocell’s measurement geometry. The detector’s alarm threshold calibration — the oil mist concentration level at which the MK-5 triggers an alarm — is set against a specific airflow condition. A fan assembly that delivers the correct designed airflow rate ensures that the detector’s alarm thresholds remain accurate to the type-approved specification. This is the specific reason why an OEM-compatible replacement fan assembly is the correct maintenance choice over a generic blower unit sourced on dimensional fit alone.
Refurbished Condition — Inspected and Operationally Assessed
The fan assembly is supplied in refurbished condition, inspected for mechanical integrity and operational condition before supply. For a rotating mechanical assembly that is in continuous operation whenever the MK-5 detector is powered, inspection of the motor, bearing condition, and impeller integrity before supply is the relevant quality check. Refurbished OEM-compatible availability also addresses the practical supply chain challenge for MK-5 fan assemblies — new OEM fan assembly stock for specific MK-5 variants is frequently discontinued or available on extended lead times, and specialist marine safety equipment suppliers with access to inspected refurbished units provide the most reliable procurement route for long-service MK-5 installations.
Resolves the Most Operationally Impactful MK-5 Failure Mode
Fan assembly failure is one of the most operationally significant failure modes in the MK-5 detector because it renders the entire detection system non-functional — even if all optical and electronic components remain fully operational. A detector with a failed fan assembly produces no valid oil mist concentration data and no alarm output, regardless of the actual crankcase condition. For vessels where the MK-5 is the sole crankcase oil mist detection system, a fan assembly failure creates an immediate and complete loss of crankcase explosion protection that cannot be partially mitigated — only resolved by restoring fan assembly function.
Technical Specifications
Component: Fan Assembly (Centrifugal Blower Unit)
Compatible System: Graviner Mark 5 (MK-5) Oil Mist Detector
Manufacturer: Graviner (Kidde / Carrier Global)
Model: MK-5
Description: MK-5 Oil Mist Detector Fan Assembly
Assembly Type: Complete unit — impeller housing, drive motor, wiring harness with connector
Fan Type: Centrifugal blower
Function: Active crankcase atmosphere sampling — draws air through MK-5 optical detection chamber
Condition: Refurbished
Benefits
Restores complete MK-5 detector function — including alarm capability — with a single assembly replacement. Because the fan assembly drives the entire active sampling function of the MK-5 detector, replacing a failed fan assembly restores the full detection chain in one repair step. There is no partial restoration: once airflow is re-established through the detection chamber, the detector’s optical measurement and alarm systems — if otherwise intact — immediately have valid crankcase atmosphere data to act on. A single assembly replacement resolves the most impactful MK-5 failure mode completely.
Maintains type-approved alarm threshold accuracy by restoring designed airflow conditions. The MK-5’s alarm thresholds are calibrated against specific airflow conditions within the detection chamber. Restoring airflow with an OEM-compatible fan assembly that delivers the correct designed airflow rate means the detector’s alarm thresholds remain accurate to the type-approved specification — not recalibrated against a different airflow condition introduced by an incompatible substitute unit.
Assembly-level replacement minimises repair time and returns the detector to service quickly. The complete assembly format — motor, impeller, and harness supplied together — means fan assembly replacement is a straightforward remove-and-replace procedure rather than a component-level motor or harness repair that requires additional time and specialist skills. For a crankcase safety system where every hour of detector downtime is an hour without crankcase explosion protection, minimising repair time has direct operational safety value.
Supports class society compliance by restoring the MK-5 to operational status. Classification societies require crankcase oil mist detectors to be maintained in fully operational condition. A vessel operating with a non-functional MK-5 due to a failed fan assembly is operating with a known crankcase protection deficiency — a condition that is reportable to the class society and can result in conditions of class or operational restrictions. Restoring fan assembly function returns the detector — and the vessel — to compliance.
Refurbished availability bridges the OEM supply gap for long-service MK-5 installations. For MK-5 systems installed 15 to 25 years ago, new OEM fan assembly stock is frequently discontinued or available on extended lead times through official channels. Specialist marine safety equipment suppliers with access to inspected refurbished fan assemblies provide the supply chain bridge that keeps long-service MK-5 detectors operational without waiting on OEM procurement timelines that are not compatible with vessel operational schedules.
Who It’s For
The Ship’s Chief Engineer Facing a Complete MK-5 Detector Outage
The MK-5 on one of your crankcase detection points has gone into fault and is producing no valid readings. After checking the optical and electronic systems, you’ve identified the fan assembly as the failed component — the motor is not running and there is no airflow through the detection chamber. You need a replacement fan assembly sourced and delivered in time to restore detector operation before the vessel’s next departure or upcoming class survey. You need a supplier who can confirm availability of the correct MK-5-compatible fan assembly in refurbished condition, with the documentation your vessel’s maintenance records require.
The Technical Superintendent Planning Proactive MK-5 Fan Assembly Replacement
You manage planned maintenance across a fleet of vessels with Graviner Mark 5 detectors that are now 15 to 20 years into service. Fan assembly failure is a known age-related failure mode in long-service MK-5 installations — motor bearings wear, brush contacts degrade, and impeller balance deteriorates over time. Rather than waiting for in-service fan assembly failures that create unplanned detector downtime, you want to carry out proactive fan assembly replacement during the next drydock cycle across detectors approaching the end of their expected fan assembly service life. You need a specialist supplier who can provide confirmed MK-5-compatible fan assemblies in refurbished condition, in the quantities required for a fleet-wide replacement programme.
The Marine Equipment Service Engineer Carrying Out MK-5 Overhauls
You service and overhaul Graviner Mark 5 detectors under contract for vessel operators and ship management companies. Fan assembly assessment and replacement — where the existing assembly shows bearing wear, motor degradation, or reduced airflow output — is a standard element of a thorough MK-5 overhaul. You need a consistent source of OEM-compatible MK-5 fan assemblies in inspected refurbished condition to maintain your service stock and support your overhaul contract schedule. You need a supplier who understands the MK-5 platform, can confirm fan assembly compatibility with the specific detector variant in question, and provides the component documentation your service records require.
Possible Applications
- Bulk carriers and general cargo vessels — Fan assembly replacement to restore complete MK-5 detector operation on vessels with medium-speed and slow-speed diesel main engines where active crankcase sampling is required at all times during engine operation
- Tankers and chemical carriers — Emergency and planned fan assembly replacement to maintain crankcase detection system availability on vessels where engine room safety management is subject to heightened regulatory oversight
- Container ships and ro-ro vessels — Rapid fan assembly repair during port calls to restore MK-5 detection capability on high-utilisation vessels where extended detector downtime is operationally and commercially unacceptable
- Offshore support vessels and platform supply vessels — Emergency fan assembly sourcing for MK-5 detectors on offshore vessels operating in remote locations where standard OEM supply lead times are not compatible with the vessel’s operational schedule
- Cruise ships and passenger vessels — Planned and emergency MK-5 fan assembly replacement to maintain crankcase protection on vessels where engine room safety standards are subject to flag state, port state, and class society scrutiny
- Drydock and ship repair facilities — Proactive fan assembly replacement during class renewal surveys and scheduled drydocking as part of systematic MK-5 detector overhaul programmes
- Marine safety equipment service contractors — Fan assembly stock maintenance for MK-5 detector servicing, overhaul, and fault repair contracts across Singapore and the regional market
Trust and Certifications
Graviner Mark 5 — The Global Reference Standard for Marine Crankcase Oil Mist Detection
The Graviner Mark 5 holds type approvals from all major classification societies including Lloyd’s Register, DNV, Bureau Veritas, American Bureau of Shipping, and ClassNK, and has been the de facto marine industry standard for crankcase oil mist detection for several decades. The MK-5’s active sampling design — driven by the fan assembly — is a core element of the detection architecture that has earned and maintained that type-approved status. Maintaining the MK-5 with OEM-compatible fan assemblies that deliver the designed airflow specification preserves the detector’s type-approved measurement performance and the vessel’s compliance with its class society’s crankcase protection requirements.
Refurbished and Inspected — Mechanical Condition Assessed Before Supply
The fan assembly is supplied in refurbished condition, inspected for mechanical integrity — motor, bearing condition, impeller, and harness — before supply. For a continuously rotating mechanical assembly within a crankcase safety detection system, mechanical condition assessment before supply is the appropriate quality standard. The refurbished designation also reflects the supply chain reality for MK-5 fan assemblies — new OEM units for mature detector variants are frequently discontinued, and specialist suppliers with access to inspected refurbished assemblies provide the most reliable procurement route for long-service MK-5 installations.
Supplied by Alright Engineering Solutions
The Graviner Mark 5 Fan Assembly is supplied through Alright Engineering Solutions Pte. Ltd., a Singapore-based specialist supplier of marine safety and gas detection equipment and spare components. Alright Engineering Solutions supports vessel operators, ship management companies, and marine service contractors with MK-5 spare parts sourcing, availability enquiries, and procurement assistance across Singapore and the wider regional market.
Accessories and Variants
Complete Graviner Mark 5 Spare Parts Support
A thorough MK-5 overhaul typically addresses multiple component categories — mechanical, optical, electrical, and electronic — in a single service event. Alright Engineering Solutions can assist with sourcing a full range of Graviner Mark 5 spare components alongside the fan assembly, supporting comprehensive overhaul programmes rather than piecemeal component-by-component procurement. Contact our team with your complete MK-5 spare parts list for consolidated availability confirmation and quotation.
Related MK-5 Spare Components Available from Alright Engineering Solutions
Graviner Mark 5 Power Supply Select Card (Part No. 39832-704) — Refurbished replacement power supply PCB with 115V/220V/230V/240V voltage selection for MK-5 detector units
Graviner Mark 5 Toroid (Part No. 44211-115) — Refurbished replacement inductive signal processing component for MK-5 detection circuit
Graviner Mark 5 Photocell Housing (Part No. 45626-122) — Refurbished replacement optical assembly enclosure for MK-5 detector units
Graviner Mark 5 Locating Spigot (Part No. 23617-403) — Refurbished replacement precision locating component for MK-5 detector assembly alignment
Graviner Mark 5 Detector Head — Replacement detector head units for MK-5 crankcase oil mist detection systems
Get in Touch
If you need to source a Graviner Mark 5 Fan Assembly for an emergency detector repair, planned overhaul, or proactive fleet replacement programme — contact Alright Engineering Solutions to confirm availability and request a formal quotation.
Our team can also support sourcing of a complete MK-5 spare parts list — mechanical, optical, electronic, and PCB components — for comprehensive detector overhaul programmes across single vessels or managed fleets.
📍 3791 Jalan Bukit Merah #06-01, E-Centre @ Redhill, Singapore 159471
