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Graviner MK5 Oil Mist Detector (OMD) – Complete Technical Guide, Maintenance, Troubleshooting, Alarm Functions & Marine Engine Safety System

Posted onJune 13, 2026

Graviner MK5 Oil Mist Detector (OMD)

Manufacturer

Graviner Ltd. (Now Part of Kidde Fire Protection)

Country of Origin

United Kingdom (UK)

Product Type

Oil Mist Detection System (OMD)

Marine Application

Marine Diesel Engine Crankcase Monitoring & Explosion Prevention System


Product Introduction

The Graviner MK5 Oil Mist Detector is one of the most respected crankcase safety monitoring systems ever installed on marine diesel engines. Designed to continuously monitor oil mist concentration inside engine crankcases, the MK5 provides critical early warning of dangerous engine conditions before serious mechanical failures occur.

Overheated bearings, lubrication failures, and abnormal friction can generate oil mist within the crankcase. If left undetected, these conditions may result in catastrophic engine damage or even crankcase explosions.

The Graviner MK5 was specifically developed to provide reliable, continuous monitoring and remains in service onboard many vessels around the world.

Original Product Image

The image above shows an actual Graviner MK5 Oil Mist Detector supplied by SM MARINE SERVICE™, complete with mounting brackets, control unit, and connection accessories.


What Is a Graviner MK5 Oil Mist Detector?

The Graviner MK5 is an electronic oil mist detection system designed to monitor the atmosphere inside marine diesel engine crankcases.

Its main purpose is to:

  • Detect oil mist formation
  • Monitor crankcase conditions
  • Provide early warning alarms
  • Protect engines from severe damage
  • Help prevent crankcase explosions

The system continuously samples crankcase air and measures oil mist concentration using optical sensing technology.

Graviner MK5 System Images

https://images.openai.com/static-rsc-4/94rO5kfDiG0R_sAaT02aLC6zwW8e3trF9YWFzr6kZRmmJnMjSWkLDrAWsXJ_y7VCHNOEYIfbTKp7avsust5SjWN5ncqh5GYGbnJUgGKRQwP6CyFGkyII7DnVWa3fncCuftA4GOKIYBInwbYDht8LMSs21NVbFV1Vo_iB6kbYcZTE9gv1wX6ufcQBNe-z4-Cp?purpose=fullsize
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How the Graviner MK5 Works

The MK5 continuously extracts air samples from engine crankcase compartments.

These samples pass through an optical measuring chamber where oil mist particles are detected and analyzed.

The detector continuously compares measured values against preset alarm limits.

When abnormal oil mist levels are detected:

  1. The detector identifies the condition.
  2. Alarm thresholds are exceeded.
  3. Visual and audible alarms activate.
  4. Engineers are alerted immediately.
  5. Corrective action can be taken before dangerous conditions develop.

This monitoring process significantly improves engine safety and reliability.


Main Features

Continuous Oil Mist Monitoring

Provides around-the-clock engine protection.

Early Warning Detection

Detects abnormal engine conditions before major failures occur.

Optical Measurement Technology

Provides reliable oil mist concentration analysis.

Compact Marine Design

Suitable for installation in marine engine rooms.

Alarm Monitoring System

Provides clear alarm indication and system status.

Proven Reliability

Successfully installed on thousands of vessels worldwide.

Long Operational Life

Engineered for continuous marine service.

Product & System Images

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https://images.openai.com/static-rsc-4/PfeA_mrFY6PCku4FtTOR13TwiOVsVIWHUZNCXyiEuVrbEhEocv_-iM1lp6prmGjTelj65skA-kLkEtFg6OA7V4JWg8uTSM9M4CwyFv-LOBjTeT2kszgRi1KaxF0Fl5wsVw4VFGecRjI7ZkEuCcemoHovzxm8o8E2TfUfFrPYrBBWbREbWui_l2ooC8S4NC9G?purpose=fullsize
https://images.openai.com/static-rsc-4/qbVIKsllpFtfc0AjZr5JHp8nib5TbabCepszS-63UBEQexlY48rt8GTWog9DNMs4yvXztTVcU6sawzbMLWFTlAQthsvny3k6s0ao830z_EUWM8xjYu136jweJCjtnqmJ3U84e3dAssUUOIdgPAU_qtuQ9hl3q2kOJCGwYouOAUrrgaRL3a9SmmTUsuzh8D2-?purpose=fullsize

Main Components

1. MK5 Monitoring Unit

The central processing and alarm device.

Functions

  • Oil mist monitoring
  • Alarm generation
  • System diagnostics
  • Sensor management

2. Optical Measuring Chamber

Measures oil mist concentration.

Functions

  • Particle detection
  • Optical analysis

3. Sampling System

Provides continuous air sampling.

Functions

  • Air extraction
  • Sample transport

4. Alarm Circuitry

Generates alarm outputs.

Functions

  • Visual alarms
  • Audible alarms
  • Remote alarm transmission

5. Mounting Assembly

Supports secure installation.

Functions

  • Equipment mounting
  • Vibration resistance

Marine Applications

The Graviner MK5 is widely used onboard:

Main Propulsion Engines

  • MAN B&W Engines
  • Sulzer Engines
  • Wärtsilä Engines
  • Mitsubishi Engines

Auxiliary Engines

  • Diesel Generators
  • Emergency Generators

Vessel Types

  • Container Ships
  • Bulk Carriers
  • Oil Tankers
  • Chemical Tankers
  • Offshore Support Vessels
  • Ro-Ro Ships

Its role is critical in maintaining engine safety and compliance with marine regulations.

Marine Installation Images

https://images.openai.com/static-rsc-4/66aLPb9SteMnLBs4pcP6T12zsH0b9iQqt9XHr1v9wSyxrVaRgTAlxXzFfouZopVkUsB6j9DqGXP2Byf4ZYJSu-wTER-46mxTXRtT006e9MdlvWc6KcJdyz1GWEp3zHDpKr7KEGbw7-c_npDMCGRLdwvgNnIet_pFi-xAJEes3hK8iFcEpZpmTML9mpgb_D_Z?purpose=fullsize
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https://images.openai.com/static-rsc-4/Ut1DThSUEZ1Ukw0vdOmL4KmpECbEQtRI3jlx02m1T-NmhyEjtsFNlu0F024mft8AOGb2zW6PXYW7uvapOTVlYgJOmiOzXvZgJKwrOfoPf_EOkhrLGTnK1mywNmypTpq8eV-P1jlIqNkdYmEcyaClwDovcVXPvc8yEXyGCUFidajdP5hMJDLK301dyepMVvI7?purpose=fullsize

Alarm Indications

Typical Graviner MK5 indications include:

Normal Operation

System operating within safe limits.

Alarm Condition

Oil mist concentration exceeds preset alarm level.

Sensor Fault

Internal sensor malfunction detected.

Sampling Fault

Air sampling system problem detected.

Power Supply Fault

Power interruption or voltage issue.

System Failure

Internal diagnostic fault condition.


Common Problems & Troubleshooting

High Oil Mist Alarm

Possible Causes

  • Bearing overheating
  • Lubrication failure
  • Excessive friction
  • Internal engine damage

Corrective Actions

  • Reduce engine load
  • Inspect bearing temperatures
  • Verify lubrication system operation
  • Follow engine manufacturer's procedures

Sampling Failure

Possible Causes

  • Blocked sampling line
  • Airflow restriction
  • Internal contamination

Corrective Actions

  • Clean sampling system
  • Inspect tubing
  • Verify airflow

Sensor Fault

Possible Causes

  • Optical contamination
  • Sensor damage
  • Electronic malfunction

Corrective Actions

  • Clean optical chamber
  • Test sensor
  • Replace faulty components

False Alarms

Possible Causes

  • Dirty measuring chamber
  • Calibration drift
  • Electrical interference

Corrective Actions

  • Clean measuring chamber
  • Verify calibration
  • Inspect electrical grounding

Maintenance Tips

Daily Checks

  • Verify normal operation
  • Check alarm indicators

Weekly Checks

  • Inspect sampling system
  • Verify airflow

Monthly Checks

  • Test alarm functionality
  • Inspect optical chamber

Quarterly Maintenance

  • Clean optical components
  • Check electrical connections

Annual Maintenance

  • Full operational test
  • Calibration verification
  • Replace worn parts if necessary

Maintenance Images

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5

Available Stock From SM MARINE SERVICE™

SM MARINE SERVICE™ supplies Graviner MK5 Oil Mist Detectors in:

  • Used Condition
  • Refurbished Condition
  • Reconditioned Condition

Available services include:

  • Supply of complete units
  • Spare parts sourcing
  • Technical support
  • Worldwide shipping

All available units can be tested prior to delivery depending on stock availability.


Why Ships Still Use Graviner MK5

Despite newer technologies, many vessels continue using the Graviner MK5 because of:

  • Proven UK engineering
  • Reliable operation
  • Simple maintenance
  • Accurate oil mist monitoring
  • Long service life
  • Global spare parts availability
  • Strong safety record

The MK5 remains a trusted engine protection device in the marine industry.


Frequently Asked Questions (FAQ)

What is the purpose of the Graviner MK5?

It continuously monitors oil mist concentration inside marine diesel engine crankcases and provides early warning of dangerous engine conditions.

Why is oil mist detection important?

Oil mist accumulation can lead to crankcase explosions and severe engine damage.

Is the MK5 still used onboard ships?

Yes. Many vessels continue to operate Graviner MK5 systems successfully.

Does the MK5 require calibration?

Periodic calibration verification and maintenance are recommended.

Can spare parts still be supplied?

Yes. Spare parts and replacement units may still be sourced through marine equipment suppliers.


Short Product Description

The Graviner MK5 Oil Mist Detector is a marine crankcase monitoring and engine protection system developed in the United Kingdom. Designed to continuously detect oil mist concentration within diesel engine crankcases, the MK5 provides early warning of dangerous operating conditions and helps prevent crankcase explosions. Its proven reliability and robust marine design have made it a trusted safety system on vessels worldwide.


Assembly Details

Complete System Assembly Includes

1. Monitoring Unit

  • Display section
  • Alarm processing module

2. Optical Measuring Chamber

  • Oil mist sensing components
  • Optical analysis system

3. Sampling Assembly

  • Air sampling mechanism
  • Sample transport system

4. Alarm Module

  • Alarm outputs
  • Monitoring relays

5. Power Supply Section

  • Internal regulation circuitry
  • Protection circuits

6. Mounting Hardware

  • Brackets
  • Installation accessories

7. Connection Interfaces

  • Signal connections
  • External alarm integration

SM MARINE SERVICE™

Marine Automation & Navigation Equipment Supplier

Available Condition:

• New Equipment
• Used Equipment
• Refurbished Equipment
• Reconditioned Equipment

Stock Location:

• Bangladesh
• China

Services:

• Worldwide Shipping
• Technical Support
• Spare Parts Supply
• Marine Equipment Sourcing

Contact Information

SM MARINE SERVICE™
Samir Market, DT Road, Pahartali, beside CDA Market, Chattogram, Bangladesh

Mobile / WhatsApp / Viber: +88 01818 929292

Email: info@smmarineservice.com

Website: www.smmarineservice.com

SM Marine Service

SM Marine Service

Marine Equipment Supplier

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