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Figure 2: NeSSI Unleashed
Modular components simplify sample system design, construction, housing, and maintenance. (Source: Parker Hannifin)
Stephen Jacobs, development associate chemist at Eastman Chemicals, Kingsport, Tenn., adds, "First, we see benefits in shrinking the footprint so we can put more things into the same area. Second, we see benefits in cutting down the labor it takes to build these systems. And third, [NeSSI] is going to allow us greater automation."
Along with reducing the size and increasing flexibility with respect to the installation, design, and layout, "the NeSSI platform has provided incentives for suppliers to look at newer technology for sample conditioning components, components with smaller dead volumes that are more reliable and easier to maintain and change out," observes Vu. "We feel the new technology will [increase] reliability and reduce the space required for sample conditioning and analytical equipment installations. It will also give us greater flexibility in terms of where we install it--we wont be limited specifically to installing systems in analyzer shelters. Another goal of this technology is to expand the implementation of sampling system and analytical technology near the sampling point or directly in the process pipe or vessel."
"ANSI/ISA-76.00.02-2002 standardized the interface between the substrate and the surface-mounted functional components such as valves, regulators, filters, flow controllers, sensors, etc.," says David Simko, marketing resources manager, Swagelok (www.swagelok.com). "It defined the physical dimensions of the interface, the location and size of the ports, and the location of the bolts. As long as those dimensions are met by the substrate and surface-mount functional component manufacturers, the two will fit together."
Sensor, substrate, and flow control component vendors are finding that modifying their existing product offerings is fairly easy and inexpensive. "In most cases, customizing existing components to be compliant with the SP76 interface standard is not difficult," says Steve Doe, analytical market manager, Parker Hannifin (www.parker.com). "We regularly customize flow paths, port configurations, or performance requirements on standard products for special customer applications, and adapting products to the SP76 interface is a similar effort."
"We were able to modify existing products quite inexpensively and make them commercially available quite easily," says Doug Mitchell, product manager for oxygen analysis products at GE Panametrics (www.panametrics.com). The company offers Generation I NeSSI-compliant oxygen and moisture analyzers.
Intuitively, users seem to know that NeSSI-compliant systems are cost-effective. However, "Getting buy-in from the business has been a challenge because we dont have the type of hard justification we would really like to have, and the businesses are insisting on it to invest in the new technology," says Vu.
On the other hand, Imperial Oils Puzic notes that, "People usually look at what it costs to buy a NeSSI system versus a conventional system, but they dont take into account additional engineering, cleaning, and assembly costs. In my experience, in looking at price quotations for both systems, even at this early stage I think the NeSSI system is cost-effective."
Figure 3: Plans for Growth
The timeline for three generations of NeSSI shows well soon be seeing smart sensors, management software, communications, and more.
Adds Jacobs, "Though NeSSI-compliant systems are pricey now, as production numbers rise and components become more standardized I think prices will drop. Im willing to pay the extra cost now to hopefully get [the technology] more established."
At least one leading user has presented its experiences with the technology as a way of generating buzz. Tatera says ExxonMobil released a paper, "Application of Smart Modular Sample Systems at an Olefins Plant," for presentation at IFPAC 2002 because, "If they didnt release the information and increase the size of the market, the devices and technologies they want to mount on these platforms wouldnt be available because vendors wouldnt have the volume [to make it worth it] for them to manufacture."
The development of the first generation of NeSSI-compliant components was relatively straightforward because SP76 was developed and approved quickly and vendors either already offered or quickly adapted existing components. In addition to various flow controllers, valves, regulators, pressure gauges, etc., NeSSI-compliant, surface-mountable oxygen, moisture, pH, and conductivity sensors are also available.
As currently envisioned, the specification for Generation II NeSSI systems involves definitions for:
1. Temperature-programmable substrates to maintain sample temperatures and dewpoints.
2. Smart, compact pressure, temperature, and flow sensors to provide measurements for validation and control.
3. "Combi"-valve, a pneumatic valve and solenoid combination component for controlling flow of sample and validation fluids.
4. Sensor Actuator Manager (SAM), a management and communications interface to manage the communications with and among sensors and actuators to standardize repetitive operating tasks and provide a gateway to an Ethernet LAN. The goal of SAM is to simplify maintenance by providing operating information about the sampling system.
5. A standardized graphical human machine interface (HMI) to allow interrogation and field-adjustment of the sampling system as well as analyzers interfaced to it.
6. Serial multi-drop sensor bus to simplify communications and connectivity.
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