Analytical systems are only as accurate as the samples they receive. Whether monitoring process gases, measuring emissions, or injecting chemicals into a pressurized system, obtaining a representative sample is critical to maintaining process control and reliability. Unfortunately, sample extraction itself presents several engineering challenges. High pressures, elevated temperatures, and maintenance requirements all influence how a sample probe assembly should be designed. A properly engineered solution helps improve measurement accuracy while maintaining process integrity and supporting safe operation.

Obtaining a representative sample

Even the most advanced analyzer cannot compensate for a poor sample. Proper probe placement is essential to obtaining accurate process data. Factors such as insertion depth, probe orientation, and flow conditions all affect sample quality. A poorly positioned probe may introduce contaminants or produce measurements that do not accurately represent process conditions.

For example, sampling near the center third of the pipe can help provide a more representative sample, while proper probe tip orientation can reduce particulate carryover into analyzer filters. These seemingly small design details can have a significant impact on measurement accuracy and long-term analyzer performance.

Common applications for sample probe assemblies include:

• Process analysis
• Flare stack emissions
• Chemical injection quills
• Wastewater analysis
• Potable water quality sampling
• Hot tapping liquid and gas streams

Maintaining process integrity

Sample probe assemblies must do more than deliver accurate samples. They must also maintain the pressure boundary and allow safe insertion and removal of the probe.

Conax Sample Probe Assemblies (SPAs) utilize Conax PG Compression Seal Fittings to provide reliable pressure and vacuum sealing while allowing adjustment and maintenance when required. Properly designed assemblies help minimize leakage, support safe operation, and maintain process integrity throughout the life of the system.

For applications that require periodic sensor maintenance or replacement, Retractable Sensor Assemblies (RSAs) allow temperature or other types of sensors to be inserted and removed without compromising the process environment. Additional safety features, including retaining chain kits and stop collars, help support safe operation in pressurized systems.

Engineered for your application

No two applications are exactly alike. Process conditions, materials, mounting arrangements, and maintenance requirements all influence assembly design.

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