Schaller Automation VN115/87plus Visatron Oil Mist Detector

Schaller Automation VN115/87plus Visatron Oil Mist Detector

The Schaller Automation VISATRON® VN115/87plus (Art. No. 11651 / 11651R) is an optical absorption oil mist detection (OMD) system engineered for high-duty marine diesel, gas, and dual-fuel internal combustion engines. Its core function is the continuous, active sampling of crankcase atmosphere to detect sub-micron oil mists caused by thermal runaways (bearing overheating, piston scuffing, or lining friction) well before explosive mixtures reach the lower explosive limit (LEL).

Fully compliant with IACS Unified Requirement (UR) M10, the VN115/87plus operates via an active, wear-free Venturi air-jet suction pump. The system continuously draws crankcase vapor simultaneously from all engine compartments through dedicated suction funnels and sampling pipes into a centralized connection box and optical measurement channel. Using an infrared (IR) LED emitter and photodiode receiver, it evaluates relative opacity. An internal heating element prevents moisture condensation on internal lenses, while fresh compressed scavenging air maintains clean optical paths across extended voyage cycles.

Model Details

• Manufacturer: Schaller Automation Industrielle Automationstechnik GmbH & Co. KG (Germany)
• Model Series: VISATRON® VN87plus Series
• Device Model: VN115/87plus (Measuring Head: VN115/87plus / Base Unit: VN115/87)
• Manufacturer Part Numbers (MPN):
  • Complete Unit / Assembly: Art. No. 11650
  • Measuring Head: Art. No. 11651
  • Exchange / Reconditioned Measuring Head: Art. No. 11651R / 11651EXP
  • Connection Box / Baseplate Interface: Art. No. 11652 / 11076
  • ATEX / Hazardous Area Version: VN115/87plus EX (Art. No. 180081)

Technical Details

Features

1. Continuous Active Sampling: Employs an internal, wear-free Venturi pneumatic jet pump powered by ship’s service air, ensuring rapid sample evacuation without moving mechanical impellers.
2. Dual-Stage Alarm Circuitry: Delivers a 2-stage safety threshold comprising a 70% pre-alarm relay for early engine slowdown and an adjustable main alarm (0.5% to 25% opacity) for instant automatic shutdown interlock.
3. Fresh Air Scavenging & Heated Optics: Utilizes pressurized fresh air rather than crankcase air to shield the optical lenses from soot, coupled with internal heating resistors to prevent false condensation trips.
4. Direct Mechanical & Electrical Backward Compatibility: Completely interchangeable with legacy VN115/87 and VN115/87 EMC units, mounting to existing pipe brackets and identical baseplate footprints.
5. Comprehensive Automation Interfacing: Features galvanic-isolated potential-free dry relay contacts alongside integrated RS-485 serial communication and optional 4–20 mA analogue opacity output for remote repeaters and AMS engines.

Compatible Engine Types

• Two-Stroke Low-Speed Marine Engines: MAN B&W (e.g., S50ME, S60MC, S70ME-C, G-series), WinGD / Sulzer (RTA, RT-flex, X-series).
• Four-Stroke Medium- & High-Speed Engines: Wärtsilä (W20, W32, W38, W46), Caterpillar / MaK (M20, M25, M32, M43), HiMSEN (H21/32, H25/33), Yanmar, Daihatsu, MTU.
• Auxiliary Diesel Generating Sets & Gas Engines: Standard crankcase extraction layouts for maritime power plants and continuous-duty offshore gensets.

Part Number Cross-References

• Schaller Base Part Numbers: 11650, 11651, 11651R, 11651EXP
• Superseded Legacy Models: VN115/87 (Art. No. 11600), VN115/87 EMC (Art. No. 11601), VN115/93
• Related Measuring Head Variants: VN116/87plus (11653, valve selector variant), VN215/87plus (11655, dual-compartment variant)
• Standard Consumables / Maintenance Spares:
  • Scavenging Air Filter Assembly: Art. No. 10798 / 270412
  • Inspection Cover Gasket: Art. No. 10166 / 355636
  • Siphon Block Unit: VN180 / 10049
  • Vibration Damper Kit (Upper/Lower): Art. No. 200211 / 200212

Applications

• Main Marine Propulsion Systems: Real-time safety monitoring of main marine propulsion engines on container ships, bulk carriers, tankers, and LNG carriers.
• Auxiliary Generating Sets: Unattended Machinery Space (UMS) monitoring on auxiliary gensets to satisfy class requirements for remote engine tripping.
• Stationary Power Generation: Heavy fuel oil (HFO), Marine Gas Oil (MGO), and dual-fuel diesel generator units in offshore oil platforms and land-based baseload plants.
• Retrofits and Overhauls: Drop-in upgrade for vessels modernizing from legacy VN/87 systems to meet revised IACS verification tests without replacing header pipes.

Frequently Asked Questions

What causes a high oil mist alarm on the Visatron VN115/87plus?

A high oil mist alarm indicates that the sample air’s optical opacity has exceeded the configured threshold (typically 2.0% opacity). This is commonly caused by severe mechanical overheating (bearing failure, seized piston ring, or gear friction) atomizing lube oil into tiny droplets. If mechanical checks show normal temperatures, inspect the detector for liquid oil carryover, blocked scavenging air filters, or condensation inside the optical chamber.

How does the VN115/87plus differ from the VN116/87plus and VN215/87plus?

The VN115/87plus is a single-channel, collective oil mist detector that samples the entire crankcase simultaneously and raises a general alarm without locating the specific crankcase bay. The VN116/87plus features internal valve selectors to identify the damaged cylinder compartment, while the VN215/87plus incorporates a dual-line system designed for large bore engines to isolate left/right banks or specific crankcase sections.

Can the VN115/87plus measuring head directly replace an older VN115/87 head?

Yes. Schaller designed the VN87plus series measuring heads (Art. No. 11651) to be backwards-compatible with the mechanical baseplate and piping footprint of the earlier VN115/87 and VN115/87 EMC models. The replacement slides into the existing baseplate mounts with minimal rewiring adjustments.

How often should the scavenging air filter and optical path be serviced?

Under standard operating conditions, the scavenging air filter should be inspected weekly and replaced every 3 to 6 months depending on engine room air quality. The optical lenses should be checked and cleaned using isopropyl alcohol whenever negative pressure drops or during planned 3,000-hour engine maintenance intervals.

Why is the “Ready” LED unlit or the Ready Relay open?

If the green “Ready” LED is off, the system’s self-monitoring diagnostic has detected a fault. Common causes include supply voltage dropping below 18V DC, drive compressed air pressure being insufficient to generate required Venturi vacuum, defective optical sensors, or failure of the internal measuring head heating system.