New Large Duct & Stack Mass Flow Meter

Product Announcement from Sierra Instruments, Inc.

MONTEREY, CA – July 15, 2009 – Sierra is proud to announce the release of its new Multi-Trak™ Model 670S Multi-Point Mass Flow Meter System.

The new Multi-Trak™ Model 670S is an advanced state-of-the-art instrument for measuring mass flow rates in very large ducts or stacks that have non-uniform velocity profiles, high turn-down requirements, dirty gas streams, wide temperature ranges and fast velocity and temperature changes. The Model 670S dynamically compensates for changes in the flow profile by using up to four independent mass flow sensing points to measure the instantaneous average gas mass flow velocity. The Multi-Trak™ is commonly used in petrochemical refining, coal-fired electric power generation, steel manufacturing and many other industrial processes that face the challenge of accurate and repeatable gas mass flow measurement in very large pipes or ducts.

An innovative, versatile and user-friendly microprocessor-based Human Machine Interface (HMI) controls all functions of the Model 670S system. The HMI is used to collect, visualize and store flow data, as well as set up the individual sensor points, thus allowing the entire system to be easily configured in the field. The Model 670S HMI integrates the functions of flow measurement, flow-range adjustment, field validation and diagnostics, and displays mass flow rate and totalized flow, as well as other configuration variables. All of this data is easily programmable from the HMI's easy-to-use touch screen.

Unlike single probe insertion sensors where each sensor point is on the same insertion probe, each Model 670S sensor point is completely independent of the others, allowing for easy field swap-out or cleaning of individual transmitters. The Multi-Trak™ features an accuracy of +/- 1% reading plus 0.5% of full scale, one-second response to changes in flow rate, and patented Dry-SenseTM Technology that eliminates sensor drift. Field validation of meter electronics and sensor resistance verifies flow meter performance. The sensors are FM, CSA, and ATEX certified for hazardous areas, and are also CE Approved.

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Complete technical information is also available free of charge from Sierra Instruments, Inc., 5 Harris Court, Building L, Monterey, CA 93940.

PH (800) 866-0200, FAX (831) 373-4402.



• The standard Model 670S system consists of up to four sensing points linked via Modbus, one control box with touch-screen HMI and a 4-20mA output module with the associated cables (power, 4-20mA output cable for daisy-chaining all sensing points).

• Innovative and user-friendly HMI offers advances over industry-standard collector boxes and allows users to:

• Average the flow of 2-4 meters

• Convert flow units

• Set up the density of the gas for mass flow measurement

• Easily configure the individual meters

• Set up alarms

• Unique multiple transmitter approach allows individual points to be removed for service or repair without shutting down the system

• Direct mass flow monitoring eliminates the need for separate temperature and pressure inputs

• Accuracy +/- 1 % of reading plus 0.5% of full scale

• Patented Dry-Sense™ technology eliminates sensor drift

• State-of-the-art calibration facility ensures a highly accurate calibration that matches the application

• High temperature option to 750ºF (400ºC) available

• Low pressure hot taps available


A global leader in the development of flow meters and controllers for over 35 years, Sierra Instruments manufacturers high performance mass flow meters and controllers for nearly any gas, liquid, or steam application. With over 150 offices in 50 countries, Sierra is positioned to provide their innovative products and support to a wide variety of industries.