Non-metallic enclosure protects unattended on-line monitoring unit

EnviroTech uses remote, low-power telemetry-enabled systems to protect an automated chemical measure system (Autolab), using non-metallic enclosures.

Mark Rawlinson, President, EnviroTech Instruments LLC

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EnviroTech Instruments develops and manufactures automated analytical systems for environmental and water quality applications. Systems with remote, low-power telemetry-enabled capabilities can continuously monitor nitrate, phosphate and ammonia concentrations in natural waters, agricultural run-off, wells and drainage systems.

Enclosure selection criteria

Autolab is an automated field-deployable nutrient analyzer system with a modular design that may be configured to measure one to four nutrients in parallel and run in unattended auto-sampling mode for long periods.

Simple user maintenance and periodic self-calibration enables Autolab 4 to cost-effectively provide high-frequency nutrient data with minimal operator overhead. Data telemetry via low-cost radio or cellular modems provides real-time visibility of field conditions for monitoring and early warning. 

The product is placed in environments characterized by extreme conditions. Controls and instrumentation must be properly protected to ensure proper functioning and to maintain optimum reliability in the transfer of critical data from field to customer.

An aluminum enclosure was specified with the initial design, but after several months of sun and rain, the finish appeared to be failing, detrimental to quality and an indication that the substrate was vulnerable to compromise. Also, metallic enclosures are subject to denting, which can cause the gasketed sealing to fail, leading to system failure.

Non-metallic enclosures

Stainless steel enclosures presented an option, but higher cost and excessive weight were undesirable. A customer using non-metallic enclosures for another controls systems lead to selection of a line of nonmetallic enclosures to house Autolab.

It was very important to include UV resistance, corrosion and moisture protection. The industrial industrial enclosures selected were originally designed as an electrical junction box for the oil refining and petrochemical industries, and later adapted for varied applications, from high-end electronics to extreme corrosive applications, indoors and out, in many sizes, cover and window options, various hinge and latch configurations and integral molded mounting flanges, with NEMA ratings of 1, 3, 4X, 6P, 12 and UL/cUL/CSA approvals.

Extensive field exposure demonstrated ability to maintain a watertight seal, reliably protect instrumentation from potential damage by corrosion, moisture, dust and other debris. In addition, the original enclosure finish and aesthetic appearance remains consistent even with extended exposure to elements and UV radiation.

www.envirotechinstruments.com

Envirotech Instruments LLC

www.stahlin.com

Stahlin Non-Metallic Enclosures were used for Autolab. Stahlin J and N Series use SolarGuard, a patented sheet molded compound for molded-in UV resistance.

- Edited by Chris Vavra and Mark T. Hoske, CFE Media, Control Engineering, www.controleng.com