Smart Exhaust Gas Sampler
Reliable Exhaust Gas Sampling for Marine Emissions Monitoring
The OXYDAN® DP7900 Smart Exhaust Gas Sampler provides stable and representative gas sampling from marine engine exhaust systems—enabling reliable operation of Continuous Emissions Monitoring Systems onboard ships.
The Challenge
Marine exhaust environments pose significant difficulties for gas sampling systems.
High dewpoint
Hot, wet raw exhaust gas must be sampled without condensation or chemical loss before it reaches the analyser.
Particulates
Soot, particulates, aerosols, and sticky deposits can foul the sampling path and contaminate expensive analyser measuring cells and optical components.
Vibrations
Continuous vibration and harsh marine operation place mechanical stress on probes, fittings, tubing, and mounting hardware.
Complex Sampling
Conventional raw-gas sampling systems are complex and maintenance-intensive, increasing downtime, service needs, and risk of unreliable measurements.
Conventional heated extractive systems can be particularly vulnerable in marine applications, where power blackouts are not uncommon. If heating to the sampling train, sample lines, or conditioning system is interrupted even briefly, cold spots and condensation may form rapidly, allowing water, acid mist, and contaminants to reach filters, coolers, and expensive analyser measuring cells. This can lead to plugging, corrosion, unstable readings, increased service needs, and extended downtime before the system is fully operational again.
This is one of the key reasons why conventional heated extractive systems often become costly and operationally fragile in marine environments.
The Smart Sampler Solution
Designed specifically for marine exhaust systems, the OXYDAN® DP7900 Smart Exhaust Gas Sampler delivers the reliability your emissions monitoring system depends on.
Stable Extraction
Provides consistent extraction of representative exhaust gas samples from marine engine ducts.
Harsh Environment Ready
Built for reliable operation in demanding marine exhaust environments.
Seamless Integration
Designed for integration with emissions monitoring systems and shipboard installations.
Controlled Delivery
Ensures controlled delivery of conditioned gas samples to downstream analyzers.
Triple P™ Sampling
Purge, Pulse, Purge determines the true system baseline of the sampling path and analyser setup, improving accuracy by separating actual gas concentrations from background drift—with cleaner operation and reduced fouling as beneficial secondary effects.
Why Dilution Sampling Matters
Reliable sampling is the critical interface between stack and analyzer. Many analyzer manufacturers focus on detection technology—the real challenge in marine CEMS is delivering a stable, representative sample.
OXYDAN® dilution sampling: principle of operation
A small stack gas sample is extracted from the stack, filtered to remove particles, and diluted with clean, dry zero air. The sample’s condensing point is then lowered, reducing the risk of condensation and enabling stable transport of the sample to the analyser and control system. One or more instruments can be used to measure the required pollutants.
The OXYDAN® dilution sampling system is based on extracting a small sample from the stack, removing particles by a proprietary filter, and accurately diluting the sample with clean, dry zero air. This lowers the sample dew point and reduces the risk of condensation and water vapour effects. Due to the relatively high sensitivity of ambient analysers, dilution does not significantly reduce measurement performance, while improving reliability and lowering maintenance. Dilution also offers the possibility to use analysers with measuring principles specific to different gases, reducing interference from other species in the sample gas.
Key benefits
- Zero-velocity filter — Effective particle removal without filter plugging.
- Accurate and stable dilution — Consistent sample conditioning.
- Low maintenance — Robust design for long service intervals.
- Reliable transport — Diluted sample delivered stably to the analyser.
- No heated sampling lines — Sample conditioned at the probe; line from probe to analyser does not require heating.
- No gas coolers — Dew point is lowered by dilution; dedicated coolers are not needed.
- Simple inert tubing — Standard tubing can run long distances (100+ m, in special configurations up to 200 m) without heating.
I have worked with in situ, heated direct sampling, heated sampling with cooler, Nafion drying, and dilution extractive sampling. There is no doubt in my mind that dilution sampling is the least maintenance‑requiring method and the one with the best data capture over time.
Technical details
Zero-velocity filter
Particulates must be removed before analysis. Reducing the gas velocity to near zero is an effective way of removing suspended particles. In the OXYDAN® filter cartridge, the velocity in the filter is near zero so removed particulates do not plug the filter elements. The filter cartridge is mounted at the probe tip and is easy to service, typically every 12 months.
Critical orifice dilution
A true critical orifice has no large internal surface area where particulates or condensables can collect. The restriction is governed by gas velocity rather than viscous friction along a surface, making it less sensitive to contamination and plugging than capillary-type devices. Another advantage is the lower temperature coefficient of flow compared with capillary restrictors.
Flange mounting and filter access
The Smart Sampler is mounted on a flange fitting (DN65 and DN80 PN6 counter flange). The unit is easily accessible. With two quick clamps, the zero-velocity sample filter can be replaced easily when the Smart Sampler has detected that it is needed.
Clean air system
A key requirement is a supply of pollutant-free, clean, and dry air. OXYDAN® uses a clean-air drying system that supplies dry, controlled dilution air to the probe. Venting the dilution air into the stack ensures that dilution air and sample remain exposed to the same static pressure, so stack pressure changes do not influence the dilution ratio.
Positive sample line pressure
The diluted sample is transported under positive pressure from the probe to the analyser. Using positive pressure ensures that any leak in the sample line is outward (sample out), not inward—so ambient air ingress cannot contaminate the sample or interfere with measurements. This supports reliable transport and allows the use of sensitive analysers.
Ejector driven by dilution air
In the OXYDAN® dilution system the sample is transported using an ejector driven by the dilution air (zero air)—not an electrical pump. With no moving parts to wear out or fail, the system offers high reliability and low maintenance. The ejector creates the motive force from the same clean, dry air used for dilution, keeping the design simple and robust.
Calibration
Dilution air (zero air) is used for zero calibration, so a separate zero gas is not needed. Provision is made for span calibration: span gas is directed to the centre of the filter, displacing stack gas so that the system samples the calibration gas. This checks the full calibration of the complete system under working conditions. Excess calibration gas is vented to the stack. This arrangement supports true system calibration under real operating conditions.
Umbilical and sample line
An umbilical connects the Smart Sampler to the stack unit. It consists of tubes and wires in an outer flexible protective casing, carrying dilution air, calibration gas, power for heating, and status/control signals. Standard umbilical lengths are 2.5, 5 and 10 m. From the stack unit, the sample line to the analyser can run 100 m or more (tested). A heated sample line is not needed—normal inert tubing such as PTFE, PFA, PVDF or any other material inert to the gas of interest is used.
Analysers
Any low-concentration analyser can be used together with the OXYDAN® dilution system to form an accurate, specific, and reliable continuous emissions monitoring system with low maintenance and traceable calibration possibilities.
Designed for CEMS Integration
The Smart Sampler serves as the sampling module within a Continuous Emissions Monitoring System (CEMS), providing stable, conditioned gas samples to downstream analyzers for greenhouse gases and other exhaust components.
When used with Instrumatic's GreenMatic Multipoint multiplexer, a single CEMS can support up to 16 Smart Samplers—enabling multi-engine, multi-stack emissions monitoring from one analyzer set. The system supports environmental monitoring platforms used for maritime regulatory compliance.
Built on Four Decades of Dilution Probe Engineering
Instrumatic has designed and manufactured dilution probe systems since the early 1980s. The first generation OXYDAN® DP7900 Smart Exhaust Gas Sampler was introduced in 1993 and has been proven in maritime service ever since—including installation on board Silja Line Symphony and Serenade from 1994 to 2014, and on many other ships and applications. Today’s system is the fifth generation of the Smart Sampler.
Originally developed for
- Industrial stack emissions
- Engine laboratories
- Environmental compliance testing
- Power plant monitoring
- Research institutions
Evolved for marine-grade operation
Over four decades, dilution sampling technology has evolved from laboratory tools into industrial marine-grade systems capable of operating in:
- High soot environments
- High humidity exhaust
- Sulfur-containing fuels
- Heavy fuel oil combustion
- LNG dual-fuel engines
- Emerging alternative fuels (methanol, ammonia, biofuels)
Designed for the Next Regulatory Wave
The maritime industry is moving beyond CO₂ into methane slip quantification, nitrous oxide monitoring, ammonia emissions, and lifecycle fuel intensity requirements.
The Smart Sampler platform is designed to support multi-gas expansion without redesign of the sampling infrastructure. Analyzer-agnostic design, modular architecture, and expandable configuration allow the same sampling system to serve evolving regulatory needs.
The platform is prepared for future IMO guidelines on CH₄ and N₂O, giving shipowners and integrators a stable foundation as reporting requirements expand.
Applications
The Smart Sampler serves a wide range of maritime and environmental monitoring applications.
- Marine emissions monitoring systems
- FuelEU Maritime compliance
- EU-ETS monitoring
- MRV emissions reporting
- Research vessels and environmental studies
- Engine test facilities
Built for Marine Environments
Engineered for the operational realities of shipboard deployment.
Robust Construction
Designed to withstand the demands of maritime operations.
Stable Long-Term Operation
Consistent performance over extended operating periods.
Ship System Integration
Compatible with ship monitoring and automation systems.
Analyzer Compatibility
Works with various analyzer platforms and configurations.
Engineered for Marine Reality
The Smart Sampler is designed for the physical and environmental conditions of shipboard operation—without compromise.
Vibration resistance
Designed to perform in engine room and funnel casing environments where vibration is inherent.
Thermal stability
Maintains sample integrity across the temperature ranges encountered in marine exhaust systems.
Salt atmosphere robustness
Industrial materials and sealing solutions selected for long-term reliability in maritime conditions.
Long-term reliability & maintenance
Simplified maintenance and serviceability for fleet-wide deployment and minimal downtime.
From Laboratory to Fleet Scale
The Smart Sampler is a scalable platform, ready for fleet-wide deployment and digital integration.
Suitable for both retrofit and newbuild, the system is designed for compatibility with cloud-based MRV and ETS reporting systems. Instrumatic understands type approval pathways, plan approval processes, and integration into existing ship automation systems—reducing risk and lead time for shipowners and integrators.
System Architecture
The Smart Sampler acts as the sampling interface between the exhaust duct and the gas analyzer.
Learn how the OXYDAN® DP7900 Smart Exhaust Gas Sampler enables reliable exhaust gas sampling for marine emissions monitoring.
Contact us to discuss integration into your emissions monitoring system.
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