Learn how probe placement, process integrity, and material selection influence performance in demanding applications.
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.
Depending on the application, sample probe assemblies may require corrosion-resistant alloys, specialized seal materials, or custom configurations designed to withstand aggressive media and elevated temperatures. Conax offers a wide range of material and configuration options to help maximize service life and reduce maintenance requirements.
Another important design consideration is wake frequency. A wake frequency calculation evaluates a sample probe assembly’s dimensions and operating conditions to determine whether it will maintain its structural integrity when exposed to process flow. If a probe experiences excessive vibration, it can fail during operation, potentially causing downstream equipment damage, unplanned shutdowns, and costly repairs.
To help customers evaluate their designs, Conax offers the Wake Frequency Solution Builder™, a free online tool that quickly performs a pass/fail evaluation based on an application’s specific parameters. For more complex applications, Conax engineers can perform the calculation and, if needed, recommend design modifications to help achieve a successful solution. In many cases, customer designs meet the required criteria by the second iteration when working with Conax’s engineering team.
For more than 75 years, Conax Technologies has worked with customers to develop standard and custom-engineered sample probe assemblies that improve measurement accuracy, maintain process integrity, and enhance safety in demanding applications.
Accurate process analysis starts at the sampling point
The quality of any analytical system begins with the quality of the sample itself. Proper sample probe assembly design helps improve measurement accuracy, maintain process integrity, and enhance safety while reducing the potential for premature failures.
Whether your application requires a standard configuration or a custom-engineered solution, Conax Technologies has the expertise to help you obtain reliable process measurements in even the most demanding environments.
Need a sample probe assembly designed for your application?
Conax Technologies engineers solutions to meet your most complex challenges. Contact our team to discuss your application and develop a solution tailored to your process.