Steel-Mass® Model 640S

Heavy-Industrial Thermal Mass Flow Meter

Our Steel-Mass® Model 640S inserts easily into ducts and pipes up to 72-inches in size to accurately monitor total gas mass flow rate. Larger probe lengths are available upon request.  Typical applications are for general industrial process control include compressed air flow, aeration basin air flow, combustion air flow, natural gas fuel flow, custody transfer and stack gas emissions flow monitoring. The Model 640S also features a high temperature option ( 750 degrees F) and a self-cleaning purge option for dirty flow enviornments.

The Model 640S is offered with a wide range of process connections (including hot tap). For very large ducts, multipoint flow averaging arrays are available, complete with a self-contained human-machine interface (HMI) panel that allows for touch-screen field programming and operation of the entire system.

This meter features Sierra's well known Smart Electronics Package for field-rangability, field flow-range adjustment, and field validation and diagnostics.  The Model 640S has very low pressure drop, and wide turndown. The Steel-Mass™ Model 640S is hazardous area approved by CSA and CRN (Canada), FM (USA), ATEX, CE and PED (EU), IEC Ex (Australia), GOST R (Russian Federation) and Chinese Pattern Approval (China). Meter accuracy is +/- 1% of reading plus +/-0.5% of full scale with repeatability of +/- 0.2% of full scale. 

Sierra has certified the Model 640S thermal mass flow meter for Greenhouse Gas (GHG) measurement meeting all requirements defined by the EPA (40 CFR Part 98).  This product is optimized for highly accurate and repeatable mass flow meters for methane (CH4) as well as N20, SF6, HFC’s, PFC’s and CO2 as called out in the EPA mandate.  The Model 640S is a popular choice for landfill gas (LFG) measurement applications.  LFG is very humid, at low pressure (20 - 40 mBarg) and about 40-60°C (100F) when it leaves the landfill.  The low pressure and dirty gas make differential pressure (DP) devices like orifice plates unsuitable, while the variable flows require a large turndown. Sierra’s Model 640S Insertion Mass Flow Meter is ideal for this application since it boasts a 100:1  turndown, has no moving parts, and generates nominal pressure drop across the immersible sensor probe. 

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