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Externally Mounted Wide-range Saturated Steam Flow Meter



OBJECTIVE: Accurately determine over a wide range of flow rates (turndown ratio) the mass flow of steam being produced & consumed at the point of use. The data will focus energy reduction efforts, quantify results & leading to cost savings for the steam system. 

DESCRIPTION: Steam is an energy-transport medium that is used for distributing heat in a wide range of applications. Steam applications such as chemical processing and industrial-scale space heating makes steam metering generalization difficult. The effective use of flowmeters can lead to cost savings for most steam distribution systems. Steam metering personnel face many hazards. Work is performed in varying weather, dirty conditions, steam systems are usually located in harsh, hot, humid and corrosive environments. Steam systems operate around 300 – 500 degree Fahrenheit temperatures at high pressure, exposing personnel to severe burn hazards. The primary source of metering error in steam systems is the use of meters that do not account for variation in density due to fluctuating steam pressure and temperature. Wetness is another source of error while metering saturated steam systems. Nearly all steam meters are flowmeters developed for gas applications with adaptations for high pressures and temperatures. They are used to measure the mass flow of dry steam instead of saturated steam present in most steam systems. In addition to high temperature and pressure conditions, steam meters should ideally cope with highly variable flows and condensate. Turndown rates for existing steam meters range from 4:1 to 100:1 depending upon the flow meter technology. Ideally, meter turndown rates for building HVAC and industrial plant process heating can account for both idling low flow and for full load conditions. Current technology does not provide for repeatable, highly accurate steam meters across a wide range of flow rates. This disparity leads to incorrect analysis of steam energy conservation measures, combined steam heat and power cost/benefit, facility energy usage, and point-of-use billing. Develop improved steam meters that are accurate across a wide range of steam flow rates, efficient to maintain, and minimally impede the flow. Ideal meters would have a turndown rate of 100:1 across all flow rates, accuracy +/- 0.01%, smooth bore, non-obtrusive flow path, and capable of withstanding internal temperatures of 200ᵒF to 400ᵒF. An accurate and cost effective steam metering solution would impact AF, DOD and commercial entities in accessing meaningful data to make informed energy usage decisions. 

PHASE I: Develop a solution that meets above requirements and conduct preliminary business case analysis (BCA) to determine implementation costs, including a return-on-investment (ROI) calculation that compares anticipated savings to expected costs. Proof-of-concept prototype(s) shall be developed to demonstrate conformance to the requirements. 

PHASE II: Initiate and complete the test plan developed in Phase I. Proof-of-concept prototype(s) shall be refined to installation-ready article and shall undergo testing to verify and validate all requirements. This process may require multiple iterations before a final design is selected. Refine BCA/ROI based on the final design. 

PHASE III: If developed technology is cost effective, passes verification / validation and qualification testing, then it shall proceed to transitioning and implementation technology. 


1: Instrumentation Engineers Handbook, RCC 1121-07, December 2007

2:  The World Market for Steam Flow Measurement, 2nd Edition. 2008, Flow Research, Inc.

3:  A Review of Steam Flowmetering Technology, October 2004, Report Number 2004/69, National Measurement Directorate, London

KEYWORDS: Steam, Flow Meter, Energy Saving 


Nick King 

(801) 777-5944 

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