Tag Archives: Natural Gas Measurement

Flowmeter Reliability and Service Win with Wastewater Biogas Plant

The old maxim – waste not, want not – has taken on a whole new meaning in places like the Santa Cruz Wastewater Treatment Facility, located near Monterey Bay in Northern California. At the plant, digester gas, a by-product of sewage decontamination, is captured and mixed with natural gas to form a type of biomass, one of today’s most innovative forms of renewable energy and environmental protection. Santa Cruz biogas produces 9.5 million kwH of electricity each year – enough to power about 3000 homes at an anticipated savings of more than $20,000 per month.

Illustration of a biogas congeneration system with thermal flow meter

Flow Meter and Vendor Reliability a Must

However, this state-of-the-art biomass technology also presents some challenges, including dependable, accurate gas measurement. And even though most wastewater treatment plants switched from problematic differential pressure devices to thermal flow meters years ago, lowering maintenance costs associated with the bioenergy process remains a critical objective for individuals like Al Locatelli, Santa Cruz co-gen and stand-by generator specialist.

Thermal flowmeter for wastewater treatment biomass gas applicationsLocatelli and others were frustrated by a lack of customer service from their thermal flowmeter vendor. So, Santa Cruz turned to a Sierra Instruments’ sales representative from Manco Controls, who installed an InnovaMass Model 240 Inline Multiparameter Vortex Mass Flow Meter to measure the natural gas used in their cogeneration system.

Thanks to the success of the initial application, the Santa Cruz facility has been using nothing but Sierra vortex and thermal mass flow meters since 2007, including our air inline flow meter, the SteelMass 640S,  and inline mass flow meter, FlatTrak™ 780S, for increased cogeneration accuracy.

“Other vendors sell you something, and you never hear from them again to help you out,” says Locatelli. “Sierra and Manco Controls have been pretty unique both in response time and reliability.”

Read the complete Santa Cruz story in Water and Wastes Digest or contact us or one of our representatives for more information. And, find out how you could slash your facility’s natural gas bill in our sub-metering infographic.

Break from the Shackles-Mid-to-Large Size Facilities Verify Utility Company Billing

As we have all been hearing in the news, natural gas is becoming a very valuable and abundant natural resource. Almost all of this increase is due to the projected growth in shale gas production which will grow to 16.7 trillion cubic feet in 2040. Now comes the big question: how are utility companies going to capitalize on this natural gas boom and how will consumers fare? This is where accurate natural gas measurement becomes critical both for utility companies and consumers, particularly in larger gas consuming mid-to-large size facilities.

Without natural gas billing verification, mid-to-large size facilities are at the mercy of utility company billing.  To break the shackles of utility companies, mid-to-large size facilities use mass flow meters to sub-meter the natural gas entering their facility. This verifies their utility bill and shows billing discrepancies. This obviously sounds like a good idea. But not many mass flow meters can accurately measure natural gas with its changing compositions and delivery pressure.  The answer to this challenging application is to use a flow meter that can deal with the changing gas compositions and density changes caused by pressure variations.

In the September/October 2013 issue of Gases & Instrumentation magazine, Sierra’s VP of Product Design, Scott Rouse, takes an in-depth look at sub-metering natural gas, including challenges associated with the varying composition of natural gas and the flow meter measurement solutions Sierra is committed to providing.

We hope you find this article insightful and encourage you to visit our Library for other in-depth articles on flow meter measurement.

Tuning Your Boiler for EPA Boiler MACT Compliance


The EPA’s Boiler MACT (Maximum Achievable Control Technology) regulations are heating up. Boiler MACT is an EPA rule to limit hazardous air pollutants (HAP) from commercial and industrial boilers and process heaters. Originally published in 2011 as a mandate driven by the Clean Air Act,  the rules are Area Source Boiler MACT 40 CFR 63, subpart JJJJJJ for smaller boilers (stores, hotels, apartments, small manufacturers, etc.) and Major Source Boiler MACT, subpart DDDDD for large ones (refineries, chemical and large manufacturing plants, large facilities).

Annual boiler compliance reports, efficiency tuning, and energy assessment are all buzz words, and facilities managers need to act fast to comply with the Boiler MACT regulations. This urgency is fueled further by the upcoming Major Source Boiler MACT final compliance deadline of January 31, 2017—which ends the three-year grace period from the date the final rules were published.

Boiler Tuning Increases Efficiency
The thrust of the Boiler MACT standards requires end users to report boiler emissions, a rule which has already been adopted in most states (See Figure 1). The addition to the mandate requires end-users to “tune” new boilers when they first start up and then perform periodic tuning.

The good news is that the purpose of the “tuning” is to measure boiler efficiency. How efficient is the boiler at turning the fuel (oil, gas, coal) and water into steam? A well-tuned boiler is around 80% efficient. If the boiler’s efficiency is less than 80%, then energy is being wasted and most likely adding hazardous air pollutants to our environment. In this case,  end users are required to fix the boiler to meet this efficiency level. “Fixing it” entails  fixing leaks, adding insulation, and cleaning heat exchanger tubes, which all add to the cost of boiler maintenance. Download Boiler MACT Information Guide.

3 Ways to Tune Your Boiler for Boiler MACT Compliance
To efficiently tune a boiler, three key measurements must be taken: air and fuel inlet flow, feed water flow, and steam output (See Figure 1).


Figure 1: Typical Boiler Flow Application

The ideal instrumentation to provide these flow measurements  for tuning are thermal flow meters for gas, ultrasonic flow meters for water, and vortex flow meters for steam output. Sierra’s variety of flow meters can help you manage your energy costs downward and meet EPA Boiler MACT regulations by providing solutions for the following three key measurements. 

1. Measure Fuel Flow to Boilers
It’s critical to precisely measure the intake fuel (oil, gas, coal) to the boiler to tune and then optimize for efficiency. Sierra’s economical BoilerTrak thermal mass flow meter, specifically designed to provide precise natural gas measurement for heaters and boilers, is an ideal product to help with monthly fuel reporting and boiler tuning to increase efficiency.

For more complex gas mixtures being burned, use QuadraTherm 640i/780i thermal mass flow meters.

2. Measure Feed Water Flow to Determine Steam Efficiency
In boiler tuning, the feed water flow to the boiler is an important measurement, since you need to measure the efficiency at which the boiler turns this feed water into steam (See Figure 1). Our  InnovaMass 240i vortex volumetric flow meters are an economical solution for water measurement applications in new boilers, while the InnovaSonic 205i ultrasonic flow meter can be retrofitted easily into existing boilers due to its clamp-on nature. The 210i  portable ultrasonic flow meter is a good analysis tool as well for periodic boiler tuning where fixed measurement devices are not already installed.

3. Measure Steam Output
To determine the efficiency of the boiler, accurate steam measurements are critical (See Figure 1). For measuring steam output, the InnovaMass iSeries vortex flow meter in insertion and inline versions are the industry-leading vortex flow meter meter for steam measurement. With its ability to measure five process variables at the same time simultaneously, and correct for density changes in steam, the InnovaMass vortex flow meter can give an accurate assessment of the efficiency of the boiler and  maximize steam productivity.

Boiler MACT Decreases Emissions
Since the intention of these Boiler MACT standards are driven by the EPA’s mandate in the Clean Air Act to develop national emissions standards, the hope would be that through Boiler MACT compliance, facilities tune their boilers to ensure the maximum boiler efficiency, which in turn minimizes the source of air pollution.   

Flow meter companies like Sierra can be part of this bigger solution. We can measure the air and fuel going into the boiler, the feed water, and the steam being produced. And from that flow measurement data, end-users can calculate the boiler efficiency and the greenhouse gases in the waste gas coming out of the flue—which is what these Boiler MACT regulations are trying to accomplish! Sierra has everything you need to fully comply with Boiler MACT immediately.

Learn more about Boiler MACT compliance and boiler efficiency.

Download Boiler MACT Information Guide.

Download Webinar on Understanding EPA’s Major Source Boiler MACT Rule.

Need additional help selecting the right flow meter for your boiler?  Contact Us today.

How Biogas Generators Work with Air Flow Meters

immersible thermal flow meter for wastewater biomass energy applications

SteelMass Flow Meter

For several years, Sierra has been working with the Santa Cruz Wastewater Treatment Facility near Monterey, Calif., to improve the rate of biogas cogeneration. Santa Cruz produces energy – enough to power 3,000 homes – by blending digester gas (a by-product of its sewage decontamination) with natural gas. This type of biomass helps create electricity using internal-combustion engines that are linked to a generator set. As you can imagine, accurate gas measurement is a key part of the whole process. Learn more about our cogeneration applications… 
The digester gas itself is produced in four large domed anaerobic digesters, which function like a stomach that breaks down solid waste. In the digesters, which are heated to an optimal 98 degrees, methane-forming bacteria break down digester acids and create large amounts of anaerobic digester gas (60% methane and 40% CO2).

Here’s where a quality, low-flow air flow meter like the SteelMass Model 640S comes in. Thermal technology:

  • Measures true mass flow directly with one instrument
  • Has excellent turndown and accuracy at low flows
  • Has a much lower cost-of-ownership
thermal flow meter for wastewater treatment digesters

FlatTrak Flow Meter

Facility operators at Santa Cruz connect the flowmeter with their monitoring system to determine if the right amount of digester gas is being produced. If readings are low, they know to check factors such as PH levels and alkalinity ratios, temperature, and feed rates.

As I mentioned above, thermal flow meter technology is ideal for biogas cogeneration applications because digester applications operate at relatively low pressures. The air flow meter causes virtually no pressure drop, accurately measuring these low flow rates. You can’t even use an orifice plate in this type of application. The SteelMass also offers 2% reading accuracy and 1% repeatability over a 40:1 turndown range, essential for digesters.

Santa Cruz also uses our inline mass flow meter, FlatTrak 780S. Both the SteelMass and the FlatTrak are immersible thermal mass flow meters and feature an insertion probe with two small diameter sensors to measure gas temperature and velocity and nominal pressure drop.

Part 1: Challenges with Submetering Natural Gas

In an article for Gases & Instrumentation magazine, I explored energy management as it relates to the natural gas industry. Natural gas exists in abundance in this country, with production expected to increase 44 percent by 2040. With such unprecedented growth in production of this natural resource, utility companies must focus on providing the most accurate gas billing possible.  So how do customers know that their utility bills are accurate? In most cases, they don’t. While this doesn’t pose much of a hardship for residential customers, the overages can be significant for mid-to-large-size facilities. This has led factories, campuses and universities to use flow meters to sub-meter their natural gas usage to confirm the readings achieved by traditional diaphragm meters. Using a flow meter for submetering, facilities can compare the utility’s gas usage totals to the natural gas measurement totals that the submeters provide (see Figure).

Flow Meter Submetering

The Challenge: Dealing with Changing Compositions and Delivery Pressure

The most common type of gas meter, seen in almost all residential and small commercial installations, is a diaphragm meter. Utility companies use diaphragm meters to measure the flow rate of natural gas and monetize the usage for billing. Within the meter, there are two or more chambers formed by movable diaphragms. With the gas flow directed by internal valves, the chambers alternately fill and expel gas, producing a near continuous flow through the meter. As the diaphragms expand and contract, levers connected to cranks convert the linear motion of the diaphragms into the rotary motion of a crank shaft, which serves as the primary flow element. This shaft can drive an odometer-like counter mechanism or it can produce electrical pulses for a flow computer (a smart meter).

Diaphragm gas meters are positive displacement meters. These gas meters measure a defined volume, regardless of the pressurized quantity or composition of the gas flowing through the meter. Temperature, pressure and heating value compensation must be made to measure the actual amount and value of gas moving through a meter. These fixed compensation variables used by utility companies can yield inaccuracies and overcharging of utility bills. For example, the diaphragm meter typically measures the natural gas volume in hundreds of cubic feet (CCF); however, the consumer is billed in therms, where one therm is equal to 100,000 BTUs. Customers are billed by taking the gas meter reading in cubic feet, converting this value to therms, then applying a multiplier that is the product of the heat value of the gas (composition dependent) times the gas density (pressure dependent).  The fact is that these multipliers are not accurate. As mentioned, the diaphragm meter is a volumetric meter, while natural gas is sold on the basis of mass. Volumetric meters cannot account for changes in gas composition nor deal with changes in pressure and temperature (and hence density). Such changes must be corrected for, and the consumer is at the mercy of the utility company to make those corrections.

Even though traditional thermal flow meters outperform volumetric meters due to relative immunity to changes in gas supply line pressure and temperature and no moving parts, they cannot automat­ically adjust for changing gas composition. When there is a large composition change, the meter must be returned to the factory for recalibration to remain accurate. However, a solution for this problem has recently emerged.  Four-sensor thermal technology now provides a method for dealing with changing natural gas compositions in the field.

In my next blog post, I’ll share more about this innovative four-sensor mass flow meter branded by Sierra as QuadraTherm. Why will it prove to be so valuable to facilities submetering their natural gas usage now and in the future?

For more in-depth information about natural gas submetering, download the article today.

And, find out how you could slash your facility’s natural gas bill in our sub-metering infographic.

Conserve Energy & Save On Your Natural Gas Bill



Flare Gas Measurement Innovation: Retain Flow Metering Accuracy Even if Gas Composition Changes

flare-blog-imageIt’s a fact oil wells almost always produce natural gas along with the petroleum. Nine times out of ten, the excess gas (typically hydrocarbons) is flared off or simply vented as-is during upset conditions in the process. The environmental impacts of “flaring” this excess gas into our atmosphere has resulted in government regulations like 40 CFR Part 60 Subpart OOOO (also known as Quad O) as well as new RSR MACT rule for refineries requiring oil & gas companies to report the flare gas emitted.

Traditionally, in upstream oil and gas applications, orifice plates and turbine meters have been used to measure the flare gas to comply with these government regulations.  Thermal mass flow meters are also gaining ground as a reliable and accurate direct mass flow measurement of flare and combustor gas.

The Problem:

Most thermal mass flow meters, however, have an inherent disadvantage in the challenging flare gas measuring application because each well head has its unique and constantly changing characteristics including varying gas composition. Over the lifetime of the well, flare gas composition and density varies, so a typical total flare gas flow measurement error could be as high as 20%. Most thermal flow meters cannot manage these gas composition changes, as they are factory calibrated for a specific gas, and need to be sent back to the factory for recalibration for the new gas composition. This is not only time consuming for the oil & gas operators and engineers, but the flare must be shut down, the thermal meter taken out of the inlet flow, and sent to the factory for recalibration.

Recent Innovation, New Solution:

Today, a new generation of four-sensor “Quad” thermal mass flow meters retains accuracy even if gas composition changes.  Sierra’s QuadraTherm 640i/780i thermal mass flow meter, is becoming a popular choice for flare and combustor (VOC/VRU) measurement due to its unique onboard qMix gas mixing software which allows operators to manage the changes in flare gas composition in the field-no factory recalibration necessary. Operators can use the onboard qMix gas mixing software to select the new gas composition and upload this new gas into the QuadraTherm meter in the field in minutes. The accuracy of the flare gas measurement for this new gas composition is retained improving downtime and  EPA regulation compliance.

Benefits of QuadraTherm thermal mass flow meters in upstream oil & gas applications:

  • High Turndowns 100:1 and measures very low flows
  • Extreme accuracy +/- 0.75% of reading (+/- 0.5% for 780i inline with built in flow plates)
  • High flows up to 60,000 sfpm (0 to 305 smps)
  • Eliminate drift with patented DrySense™ sensor-Lifetime sensor
  • qMix Gas Mixing App manages changes in gas composition in the field—no recalibration needed
  • In-situ ValidCal™ Diagnostics, Dial-A-Gas & Dial-A-Pipe
  • Low and high-pressure hot tap
  • 40 CFR Part 60 (Quad 0), Boiler MACT Greenhouse Gas (GHG) certified


New Flare Gas Measurement Application Tech Note!

Download our new Flare Gas Mass Flow Measuring Tech Note  for more information on how qMix gas mixing software makes QuadraTherm thermal mass flow meters the most flexible and economic solution for flare and combustor gas measurement.

New QuadraTherm 640i / 780i: Introducing The World’s Most Accurate Thermal Mass Flow Meters

From Sierra’s beginning over forty years ago, we have been driven by the vision of supplying industrial customers with the world’s most accurate thermal mass flow meter. And, we knew it was a “sensor” game.

The development of an industrialized metal-sheathed sensor in the early 80s was Sierra’s first big step, but we didn’t stop there.   Many successful innovations followed, but in 1999 Sierra experienced a major breakthrough with the introduction of our patented no-drift DrySense™ thermal mass velocity sensor. Our engineers now recognized they were on the cusp of realizing their vision.

Realizing the Vision

Thermal dispersion technology, by its very nature, uses the physics of heat transfer and conservation of energy in a closed system to measure mass flow rate. This means that for a thermal dispersion mass flow meter to achieve the greatest accuracy, it must solve the First Law of Thermodynamics (Heat Energy In = Heat Energy Out) for each data point.

As you can imagine, solving the First Law for thermal dispersion technology was no easy task.  Decades of “hard-nosed dedication to excellence” and years of testing finally yielded the secret in the form of two revolutionary new technologies—QuadraTherm™ and iTherm™, now both patented worldwide.

Today, I am proud to say the never before possible, is Now Possible with QuadraTherm 0.5% of reading accuracy.  Learn more…

Part 2: Challenges with Submetering Natural Gas

I previously shared a post on how mid-to-large size facilities can save money by taking the initiative to submeter natural gas usage, titled Part 1: Challenges with Submetering Natural Gas. The traditional diaphragm meters used by utility companies rely on fixed compensation variables that can lead to inaccuracies and overcharging. While this can affect residential customers, it comes as no surprise that it can have a major impact on businesses with a large amount of square footage, such as a multi-building campus.

As a result, these facilities often employ flow meters to better measure total natural gas usage to reflect more accurate billing and total energy costs. But, traditional flow meters cannot automatically adjust for changing gas composition and pressure changes, effectively limiting their usefulness when they need to be continuously recalibrated at the factory. Our solution? Four sensors instead of two, an innovative take on solving an age-old problem of flow meter flexibility.

Flow Meter Natural Gas SubmeteringFour-sensor Thermal technology by Sierra Instru­ments provides a method for dealing with changing natural gas compositions and density changes caused by pressure variations. This flow meter corrects for den­sity variations using the AGA Report No. 8-approved density equations for natural gas. Instead of having two sensors, one a temperature sensor in the temperature probe and the other, a self-heated sensor in the velocity probe, there is an additional sensor strategically located in each, giving a total of four sensors. The extra temperature sensors in the stem of each probe measures the stem conduction, which is a function of the total heat transfer budget and must be accounted for. Stem conduction depends on the ambient tem­perature outside of the pipe (See Figure ).

Improved Flow Meter Measuring Accuracy

In this four-sensor Thermal technology, branded QuadraTherm by Sierra, a traditional analog measurement circuit is now a hyper-fast microprocessor that runs a comprehensive flow-measurement algorithm set. This algorithm solves the first law of thermodynamics and calculates the various heat transfer properties of the gas.  Accuracy for this new breed of mass flow meter is +/- 0. 5% of reading for in-line meters, better than the typical 1.0% reading of a utility grade diaphragm meter.

Four-sensor technology has the capability to address changes in natural gas compositions with “Dial-A-Gas”. The meter can hold four gas mixtures onboard, allowing facilities managers to select the appropriate heating value through software Sierra calls qMix. The QuadraTherm essentially eliminates the need to send a thermal flow meter back to the factory for recalibration each time the gas composition changes or the application changes. QuadraTherm also has the capacity to totalize four different billing tiers, allowing consumers to enter different dollar rates for baseline usage and every tier exceeded.

In the next decade, efficient energy management will be a cornerstone to the profitability of mid- to large-size facilities. Through managing energy costs, including natural gas, facilities can save thousands of dollars a year in reduced utility bills. Facilities managers will continue to need innovative new gas meters like QuadraTherm for accurate and flexible sub-metering to drive down energy costs and keep utility companies in check. Find out more about this emerging trend by downloading the full article, and be sure to check out our sub-metering infographic to find out the secret to slashing your facility’s natural gas bills.

Sierra’s Biggest Stories from 2016


2017 is here and this year will bring many new exciting developments at Sierra, but before launching completely into the new year, let’s take a look back at our top stories of 2016.

New at Sierra in 2016

We’re always looking for new ways to communicate and interact with our customers and industry. Find out about three new initiatives we started in 2016 that will continue to grow in 2017.

Minute Flow Tip YouTube Videos

At Sierra, we get very excited about flow measurement and control as you can imagine, and sometimes we want to spread the information we have quickly without a whole lot of fuss. That’s the spirit behind the “Minute Flow Tips” video series we launched in 2016.  We cover a variety of flow measurement control tips to help you strengthen your flow measurement capability to improve your overall process quality.

Application Tech Notes

Sometimes you need quick information about a specific application, that’s where our new Tech Notes come in. You can quickly and easily learn about the challenges of an application and which flow meter or controller will help overcome this and provide precise measurement. You can currently download Tech Notes on Upstream Oil & Gas, Burner Control in Manufacturing and Beverage Manufacturing Applications with more applications coming in 2017.

Sierra on Instagram

In 2016 we expanded our social media presence to Instagram. You can now follow us to get an inside glimpse at what happens at Sierra and view photos of flow meter applications from around the globe. Have a photo of a Sierra flow meter in action? Send it to us and you may just see your name and photo in our feed!

Most Popular Blog Posts from 2016

Our Let’s Talk Flow Blog gives us an opportunity to share with you the latest happenings at Sierra, product news and flow meter education. Here are the top three articles our readers found most interesting in 2016. If you missed one, click through and catch up!

boilermactlogo-3Tuning Your Boiler for EPA Boiler MACT Compliance

Compliance with the EPA’s Boiler MACT regulations was a hot topic in 2016 with the three-year grace period on Major Source Boiler MACT coming to an end. In this article, we discuss the regulations, three ways to tune a boiler for compliance with the regulations and how flow meters can be used to help companies comply.

For Vortex Flow Meters, Accuracy Matters in Steam Energy Flow Measurement

innovamass-landing-page-slideMost facilities managers are in the hot seat to account for all of the flow energy, going in and out of their facility which is no easy task. This mandate is no different for steam flow measurement. In this article, we discuss the challenges of steam flow management and which type of flow meter is most accurate and maximizes steam productivity best.


sierra flare gas solutionsHow to Reduce Methane Emissions with Thermal Mass Flow Meters

Meeting EPA CFR 40 standards for methane emissions in the oil and gas industries continues to be a hot topic. In this blog post, we discuss how flow meters can help companies comply and Sierra’s solutions.

Oldies, but Goodies

We publish a lot of new content each year but there is some content from previous years that continues in popularity and helps customers. Here’s a look at the top three articles from previous years that are still popular with readers.

Flow Meter Do’s and Don’ts with Ammonia

Flashback to Pitcon 2012 for the inspiration for this blog post. There were many engineers and researchers stopping by our booth that year in need of a solution for ammonia flow measurement. Find out the precautions you need to take when using a flow meter in an ammonia application.

Insertion Flow Meter Straight Run Requirements

This instructional post continues to be a helpful resource for those deciding on the most optimal placement of their industrial thermal insertion mass flow meter. Jim Oswald, Sierra’s Technical Support Manager, shares his technical expertise and tribal knowledge to help you find the best point of insertion.

Wireless Networks for the Digital Flow Meter, Part 1

Need to improve network speed to flow meters that are wired into your infrastructure? Wireless communication continues to be a popular topic and this post provides an example of how you can use wireless technology as a solution to this problem.

2017 Preview

This year, as we do every year, we have big plans to make your experience with Sierra even better and more engaging.  Keep an eye out for our increasing library of Application Tech Notes, Infographics, and videos to both inform and help guide you in flowmeter choice and selection. In addition, we have some very exciting product launches and improvements that we know you will love. As always, Sierra will continue to serve our community through outreach programs and focus on employee and customer training programs.

Stay tuned in 2017 – It’s going to be a great year!

New QuadraTherm 640i / 780i: Accuracy Never Before Possible!

View of QuadraTherm Sensor Looking Up the Probe Shaft

Innovative QuadraTherm Four-Sensor Design

Traditional thermal sensors have two sensors—one temperature sensor and one velocity sensor, each in a separate probe sheath. QuadraTherm (the term “Quad” meaning “four”) introduces four sensors—three precision platinum temperature sensors and one patented DrySense mass velocity sensor. Performance improvements never before possible are gained as the QuadraTherm Technology isolates forced convection (the critical variable for measuring gas mass flow rate) by calculating and then eliminating unwanted heat-transfer components, like sensor stem conduction, one of the major causes of false flow readings.

iTherm, the Brains Behind it

iTherm is the true “Brain” of the instrument and a revolutionary, living, learning algorithm set made possible by today’s hyper-fast microprocessors and QuadraTherm sensor inputs. iTherm manages changes in gas flow, gas temperature and gas pressure, as well as outside temperature, via a comprehensive heat-transfer model. The result of iTherm is a proprietary, fundamentally different gas mass flow rate calculation using all pertinent variables for the most precise, stable and accurate thermal mass flow measurement possible.

I am proud to say the never before possible, is Now Possible with  QuadraTherm 0.5% of reading accuracy.  Learn more…