Daihatsu MD-9M Oil Mist Detector (OMD) – Complete Technical Guide, Maintenance, Troubleshooting, Alarm Functions & Engine Protection System
Daihatsu MD-9M Oil Mist Detector (OMD)
Manufacturer
Daihatsu Diesel Mfg. Co., Ltd.
Country of Origin
Japan
Product Type
Oil Mist Detector (OMD) / Crankcase Monitoring System
Marine Application
Main Engine & Auxiliary Engine Crankcase Protection System
Product Introduction
The Daihatsu MD-9M Oil Mist Detector (OMD) is a critical marine engine safety device designed to continuously monitor oil mist concentration inside diesel engine crankcases. Manufactured by Daihatsu Diesel Japan, the MD-9M is widely used on marine auxiliary engines and generator engines to provide early warning of abnormal crankcase conditions.
Oil mist detection is one of the most important safety functions in marine diesel engines. Excessive oil mist inside a crankcase can indicate overheating bearings, lubrication failure, hot spots, or mechanical damage that may lead to a crankcase explosion if not detected early.
The MD-9M continuously samples air from multiple crankcase compartments and provides visual indication, alarms, and shutdown signals when dangerous oil mist levels are detected.
Original Product Image
The image above shows an actual Daihatsu MD-9M Oil Mist Detector supplied by SM MARINE SERVICE™, featuring the oil mist density indicator, crankcase selector rotary valve, alarm indicators, and control functions.
What Is the Daihatsu MD-9M Oil Mist Detector?
The MD-9M is a crankcase safety monitoring system that continuously measures oil mist density inside engine crankcase spaces.
Its primary purpose is to:
- Detect abnormal oil mist levels
- Prevent crankcase explosions
- Protect diesel engines
- Provide early fault warning
- Improve engine safety
- Reduce machinery damage
The system continuously scans each crankcase compartment through a rotary sampling valve and measures oil mist density before dangerous conditions develop.
Daihatsu Oil Mist Detector Images
How the Daihatsu MD-9M Works
The MD-9M uses a sequential sampling system to monitor oil mist concentration from multiple crankcase compartments.
Operating Process
- Air samples are drawn from crankcase spaces.
- Rotary valve selects individual crankcase compartments.
- Optical sensing technology measures oil mist density.
- Measured values are displayed on the oil mist density indicator.
- Alarm thresholds are continuously monitored.
- If oil mist exceeds preset limits, alarms activate.
- Severe conditions can trigger engine slowdown or shutdown systems.
This process ensures early detection of dangerous crankcase conditions.
Main Features
Continuous Crankcase Monitoring
Provides 24-hour engine protection.
Multi-Point Sampling
Monitors multiple crankcase compartments sequentially.
Oil Mist Density Indicator
Displays real-time oil mist concentration.
Rotary Crankcase Selector
Identifies affected crankcase compartment.
Early Warning Alarm
Provides advance warning before dangerous conditions develop.
Final Alarm Output
Triggers engine protection systems.
Reliable Japanese Engineering
Proven performance on marine diesel engines.
Additional Product Images
Main Components
1. Oil Mist Density Indicator
Displays measured oil mist concentration.
Functions
- Visual indication
- Alarm threshold monitoring
- Trend observation
2. Rotary Valve Selector
Sequentially samples crankcase compartments.
Functions
- Crankcase identification
- Sample selection
3. Optical Measuring Chamber
Measures oil mist density.
Functions
- Oil mist detection
- Signal generation
4. Alarm Circuit
Provides warning and shutdown outputs.
Functions
- Slight alarm
- Final alarm
- Fault indication
5. Sampling Pump System
Draws crankcase air samples.
Functions
- Air circulation
- Continuous monitoring
Marine Applications
The Daihatsu MD-9M is commonly installed on:
Auxiliary Diesel Engines
- Daihatsu Generator Engines
- Auxiliary Power Units
Main Propulsion Engines
- Medium-Speed Diesel Engines
- Marine Generator Sets
Engine Protection Systems
- Crankcase Safety Systems
- Engine Monitoring Networks
Vessel Types
- Container Ships
- Bulk Carriers
- Tankers
- Offshore Support Vessels
- LNG Carriers
- Ro-Ro Vessels
Marine Installation Images
Alarm Functions
Normal Condition
Green indicator remains active.
Trouble Alarm
Indicates system fault or sampling issue.
Slight Alarm
Activated when oil mist concentration begins rising above normal levels.
Possible Causes
- Bearing overheating
- Lubrication issues
- Mechanical wear
Final Alarm
Activated when dangerous oil mist concentrations are detected.
Possible Causes
- Hot bearing
- Severe overheating
- Crankcase fire risk
Common Problems & Troubleshooting
Trouble Alarm Active
Possible Causes
- Sampling line blockage
- Pump malfunction
- Sensor contamination
Corrective Actions
- Inspect sampling lines
- Check pump operation
- Clean detector chamber
False Oil Mist Alarm
Possible Causes
- Dirty optical chamber
- Calibration drift
- Moisture contamination
Corrective Actions
- Clean optics
- Verify calibration
- Remove moisture source
No Sampling from Crankcase
Possible Causes
- Blocked pipework
- Faulty rotary valve
Corrective Actions
- Clean sample lines
- Inspect valve operation
Rotary Valve Not Operating
Possible Causes
- Mechanical wear
- Drive failure
Corrective Actions
- Inspect mechanism
- Repair or replace components
Maintenance Tips
Daily Checks
- Verify normal indication
- Check alarm status
Weekly Checks
- Inspect sampling lines
- Verify selector operation
Monthly Checks
- Test alarm circuits
- Verify crankcase scanning sequence
Quarterly Maintenance
- Clean optical chamber
- Inspect pump performance
Annual Maintenance
- Complete calibration
- Functional testing
- Alarm verification
Maintenance Images
Why Ships Still Use Daihatsu MD-9M
The MD-9M remains widely used because:
- Proven Japanese technology
- Reliable crankcase protection
- Simple operation
- Accurate oil mist detection
- Long service life
- Easy maintenance
- Effective engine protection
Many vessels continue operating MD-9M systems successfully due to their reliability and safety performance.
Frequently Asked Questions (FAQ)
What is the purpose of the MD-9M?
The MD-9M detects dangerous oil mist concentrations inside diesel engine crankcases.
Why is oil mist monitoring important?
Excessive oil mist can indicate overheating and may lead to crankcase explosions.
What does the rotary selector indicate?
It identifies the crankcase compartment currently being monitored.
Can the MD-9M stop an engine?
Yes. Through connected protection systems, final alarms may trigger slowdown or shutdown functions.
Does the detector require periodic calibration?
Yes. Regular calibration and testing are recommended for reliable operation.
Short Product Description
The Daihatsu MD-9M Oil Mist Detector (OMD) is a Japanese-engineered crankcase safety monitoring system designed for marine diesel engines. It continuously measures oil mist concentration inside crankcase compartments, provides early warning alarms, and helps prevent catastrophic engine failures. Its proven reliability and effective protection make it a trusted safety device on ships worldwide.
Assembly Details
Complete MD-9M Assembly Includes
1. Main Control Unit
- Oil mist density indicator
- Alarm display section
2. Rotary Valve Assembly
- Crankcase selector
- Sampling distribution mechanism
3. Optical Detector Chamber
- Oil mist sensing section
- Measurement optics
4. Sampling Pump Assembly
- Air circulation pump
- Sample transport system
5. Alarm Module
- Slight alarm output
- Final alarm output
6. Electrical Connection Assembly
- Terminal blocks
- Interface wiring
7. Mounting Hardware
- Brackets
- Fasteners
8. Sampling Line Connections
- Crankcase piping connections
- Air sampling interfaces
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