In the Swagelok design (Wawroski 2004), interconnecting tubes called “basic flow components” (similar to the Circor tube sets) are inserted in channels machined into a platform called a “substrate layer.” The building blocks are mounted on top of the substrate layer and are interconnected to the flow tubes from the bottom. A separate manifold layer, beneath the substrate layer platform, is used to connect the flows between the substrate channels. The building blocks joined with the valves, regulators, gauges, sensors, and other system components constitute the “surface‐mount” layer.
Figure 3‐28a Parker‐Hannifin NeSSI interconnection system.
Figure 3‐28b Circor NeSSI interconnection system.
Figure 3‐28c Swagelok NeSSI interconnection system.
Regardless of the platform, sensors and other system components are accessible from the top of the platform. Translating a traditional flow schematic into a NeSSI system may be challenging for someone unfamiliar with the manufacturer’s architecture. However, computer software has been designed to assist in the development of NeSSI structures from a given schematic. Figure 3‐29 illustrates a generic miniature modular CEM system.
Figure 3‐29 Example of a miniature modular CEM system.
These modular sampling systems have less dead space than the tube and fitting system and are less likely to leak than the traditional nut and ferrule fittings by using surface‐mounted o‐rings. However, if a leak occurs, it may be more difficult to find and resolve the leak.
NeSSI systems have seen the greatest application when multiple identical extractive systems are required. In other applications, NeSSI components may be substituted for part of an extractive system, such as the calibration gas distribution system for daily CEM system verifications, or calibration gas dilution systems. The size and modularity of the modular platforms make them ideal for the application of miniature and micro sensors and analyzers (Aquino 2003; Chon 2004). The University of Washington Center for Process Analysis and Control (CPAC) is the primary information resource for conference proceedings, publications, and current progress on NeSSI systems (Dubois 2009; Dubois et al. 2004; Marquardt et al. 2009).
REFERENCES
1 Aldina, G.J. (1985). Continuous Emission Monitoring System for Dry‐Basis Pollutant Mass Rate Measurements. Private communication.
2 American National Standards Institute (ANSI)/Instrument Society of America (ISA) (2002). ISA Standard: Modular Component Interfaces for Surface‐Mount Distribution Components. ISA 76.00.02002. New York.
3 American Society of Mechanical Engineers (ASME) (1971). Fluid Meters – Their Theory and Application, 6ee. New York: ASME.
4 Appel, D. (1994). Calibration of Dilution Extractive Systems. Franklin, MA: Thermo Environmental Instruments, Inc.
5 Aquino, D. (2003). The incredible shrinking sampling system. CEP Magazine. December 2003, 912.
6 Baldwin, T. (1995). Evaluation of stack criteria pollutant gas absorption in the new generation thermoelectric water condenser fitted with laminar impinger type heat exchangers. In: Proceedings of Acid Rain & Electric Utilities: Permits, Allowance, Monitoring, and Meteorology, 555–574. Pittsburgh: Air & Waste Management Association.
7 Batug, J.P., Romero, C.E., Yilmaz, A. et al. (2004). Emission monitoring system and method. US Patent 6,701,255 B2.
8 Baugham, L. (1996). Active control of dilution probes. In: Proceedings – Continuous Compliance Monitoring Under the Clean Air Act Amendments, 154–161. Pittsburgh: Air &Waste Management Association.
9 Baugham, L. (1997). Dilution control method and apparatus. U.S. Patent No. 5,596,154. 21 January 1997.
10 Bembe, R. (2019). Heated sample line maintenance. Power Point Presentation at ESC Fall 2019 User Group Meeting. Austin: Environmental Systems Corporation.
11 Bergshoeff, G. and van Ijssel, F.W. (1978). Monitoring gases – a new stack sampler: Parts 1 and 2. International Environment & Safety March: 32–34; (June):134–136.
12 Berry, R. (1999). Optimizing CEMS Performance Through Advanced QA/QC Practices. TE‐1114127. Palo Alto, CA: Electric Power Research Institute.
13 Berry, R.S. (2000). Evaluating the measurement biases in CEMS. Paper presented at the Air & Waste Management Association Meeting, Salt Lake City, paper 264 (18–22 June 2000).
14 Brouwers, H.J. and Verdoorn, A.J. (1990). A simple and low‐cost dilution system for in‐situ sample conditioning of stack gases. In: Proceedings – Specialty Conference on Continuous Emission Monitoring – Present and Future Applications, 380–389. Pittsburgh: Air & Waste Management Association.
15 Chon, M. (2004). Simplify process analyzers with NeSSI. Control Magazine.
16 Defriez, H. (1992). Private communication.
17 Dubois, N. (2009). Rethink Sampling System Automation. Chemical pocssing.com/article/2009/096/?page‐full.
18 Dubois, N., van Vuuren, P., and Gunnell, J.J. (2004). Nessim Generation II Specification. Seattle. University of Washington Center for Process Analytical Chemistry. https://www.depts.washington.edu/cpac/NeSSI/documents/NeSSI_Gen_II_Spec_6_21_04.pdf (accessed 11 November 2021).
19 Dudley, T. and Cost, M. (2012). Eevolving applications that demonstrate the value of the Nessim platform – sampling system development for the field and laboratory. International Foundation Process Analytical Chemistry (IFPAC) Conference. Seattle. University of Washington Center for Process Analytical Chemistry.
20 Dunder, T.A. and Leighty, D.A. (1997). Comparison of thermoelectric and permeation dryers for sulfur dioxide removal during sample conditioning of wet gas streams. Paper presented at the Air & Waste Management Association meeting, Ontario. Pittsburgh: Air & Waste Management Association, 97‐MP7.04 (8–13 June 1997).
21 Dunder, T.A. and Stone, C.D. (1995). Permeation and adsorption of carbon monoxide in polymeric tubing used for extractive emissions monitoring applications. Paper presented at the Air & Waste Management Association Meeting, San Antonio, paper 95‐TA16B.02 (8–13 June 1995).
22 Fischer, B. (1993). External low flow dilution probe for extractive CEMS – field study and certification. In: Continuous Emission Monitoring – A Technology for the 90s, 329–337. Pittsburgh: Air & Waste Management Association.
23 Freitag