Tag Archives: MEMS Sensor

New From Sierra, MEMS-based Thermal MFC’s Set the Long-Term Stability Bar – High!


We have been in the capillary thermal mass flow business for nearly 45 years, many have asked us why we recently introduced MEMS thermal mass flow controllers into our product offering.  Combining superior physics, high reliability, and unparalleled flexibility, our new Sierra MEMS-based RedySmart brand mass flow controllers complement our Sierra Capillary-based SmartTrak brand mass flow controllers.

Unparalleled Stability









Our RedySmart MFC targets the Biopharm industry where historically, Sierra did not have a product with a perfect fit.  Biopharm OEMs appreciate the modularity, compact size, and price of the RedySmart MFC.  The incredible long term stability is probably the biggest factor.  Making a big statement in the industry, all Sierra MEMS devices, including RedySmart and RedyCompact, come with a Lifetime No-Drift Sensor Warranty for long-term peace of mind for end-users that will rely on these devices for top results.  Sierra is the only company in the industry to stand behind MFC sensor stability claims with a warranty.  Stability is made possible by state-of-the-art high-precision MEMS (Micro-Electro Mechanical Systems) technology utilizing an advanced CMOS  (Complementary Metal Oxide Semiconductor) sensor architecture.











50x Magnification of Redy MEMS Sensor

RedySmart thermal mass flow devices contain no moving parts and are unaffected by upstream temperature and pressure fluctuations, resulting in exceptional accuracy and repeatability.   With a compact footprint, easy integration onto a cost-effective multi-device gas mixing blocks, and a wide array of communications protocols, Sierra can now produce a gas mass flow meter or controller to meet nearly any requirement.

Mass Flow Controllers Support Ventilator Testing

Precision Mass Flow Control Validates Ventilator Accuracy

It’s actually a life and death matter, and we take this very seriously. Accurate mass flow control is crucial in the process of validating the accuracy of oxygen flow for mechanical ventilators and respiratory medical equipment. Ventilators are designed to pump oxygen into a patient that is breathing insufficiently or unable to breathe on their own. A ventilator machine moves air into and out of a patient’s lungs to ensure their body receives the oxygen it needs to survive, and hopefully recover from the effects of the COVID-19 virus.1  To make sure patients are getting the exact amount of oxygen needed, in the field ventilators must be meticulously validated to each flow range in order to be effective.

Proven & Accurate Testing for Respiratory Equipment You Can Trust

With over 20 years of proven performance, Sierra is known for providing scientists with precision mass flow control and the ultimate lab research flexibility.  Every Sierra SmartTrak 100 has a wide operating flow range and pressure requirements and is pre-programmed for up to 10 gases that are field selectable. Because of this, Sierra’s SmartTrak is used as a validation standard in order to verify that the ventilators are performing within specification. For ease of use, scientists can easily change set points, flow rates, engineering units on directly on the push-button display or remotely with the Pilot Module. For particularly challenging applications, Sierra’s dedicated engineering team can provide custom engineering solutions to meet precise customer requirements.

The heart of the SmartTrak 100 mass flow controller is a platinum-wound capillary sensor that directly measures thermal mass flow. Sierra’s patented laminar flow element eliminates non-uniformities and conditions the flow in the capillary sensor into stable laminar behavior where mass flow measurement occurs.

Key SmartTrak 100 Features

  • All clean gases including toxics and corrosives
  • Accuracy – Standard: +1.0% of full scale, High Accuracy – Up to +0.5% of full scale
  • Repeatability – +0.2% of full-scale
  • Multi-Gas – Preprogrammed for up to 10 gases – Field selectable
  • Flow Range – 0 to up to 1,000 slpm
  • Local/remote display and pushbutton interface
  • Buy Online-Fast Next Day delivery

Learn how Sierra’s mass flow controllers are used to accelerate Bioprocessing from Pilot to Full-Scale Production.



  1. Sonas Home Health Care, June 28, 2018,  “What is a Mechanical Ventilator?” https://www.sonashomehealth.com/medical-ventilator/ .

Introducing RedyCompact Mass Flow Meters and Regulators- New Video

Mechanical rotometers have been a staple for flow measurement since the early 1900s, giving engineers and scientists fast and economical gas flow measurement. Sierra introduces the next generation advancements in this technology with the RedyCompact™ mass flow meters and regulators,

Watch Sierra’s NEW video to learn how this unique battery-powered digital mass flow meter, regulator or flow switch for gases offers users the ultimate upgrade to mechanical rotameters.

RedyCompact is ideal for industries that have recognized the limitations of their rotameters. As volumetric meters, rotameters are unable to measure the gas mass flow rate. The results in  poor accuracy. The RedyCompact has an easy-to-use digital interface and provides users mass flow measurements at a lower cost than mass flow meters or controllers. To bring your process or system into the digital age with minimal investment, the RedyCompact is the perfect drop-in replacement for common sight-glass rotameters meters.

RedyCompact Provides Users with:

  • Drop-in replacement of outdated rotameters
  • Direct Mass Flow, not volumetric, for highest accuracy & repeatability
  • Lifetime no-drift sensor guarantee
  • Large Touch-screen display offers intuitive navigation and automatic screen adjustment (0°/90°/180°/270°) for easy installation and visibility
  • High-precision MEMS (Micro-Electro Mechanical Systems) technology utilizing an advanced ultra-stable
  • CMOS (Complementary Metal Oxide Semiconductor) sensor
  • Flow alarms to notify you when a flow event happens

Discover more about why RedyCompact is the ultimate VA replacement. Visit the product page.

Request a quote.


Why Mass Flow Controllers are Replacing VA Meters in Bioreactors

Upgrading to A Gas Mass Flow Controller Provides Greater Reliability for your Bioreactor

When it comes to efficient bioreactor performance, precision mass flow control gas is critical. It is essential that bioreactor manufacturers have reliable, repeatable, and flexible gas supply systems for their bioreactors.  Due to the ever-evolving demands and critical and complex nature in the bio-industry, VA meters commonly used in this application are no longer suitable and bioreactor manufacturers are now turning towards mass flow controllers to strengthen their process.

Bioreactor Application Challenges

Reliable and stable control of the supply of oxygen to the bioreactor is a complex process. The metabolism of the microorganisms is dependent on the dissolved oxygen concentration, so that a precise gas flow control is critical. Therefore, the oxygen concentration must be lowered or increased as required (mixture of N2 or O2).

Another important variable is the pH value. For microbial bioprocesses this is done with the addition of liquid acids and alkalis. For cell cultures, on the other hand, one uses only liquid alkalis. The liquid acid can damage the cells so you use CO2 instead of liquid acid. There are many different bioreactor processes and each has its specific reason to use and control gasses, but they all require precision gas flow control for optimal metabolism of micro-organism which is essential to vaccine testing and development.

VA Meters No Longer A Viable Solution

Traditionally bioreactor manufacturers use VA meters in their bioprocesses.  However, with changing bioreactor technology several major factors are impacting how a mass flow controller in a bioreactor must work eliminating VA meters as a viable option.
  • Miniaturized  design  for  custom  OEM  devices
  • Automated features for higher performance processes
  • Preventing contamination events caused by bioreactors
First, bioreactors are becoming smaller. Miniaturized stirred tank bioreactors are cost-effective solutions for biotechnology industries that require rapid process developments for smaller-scale experimentations. These bioreactors provide a cost-effective approach that requires consistent, accurate gas flow measurements that can adapt automatically to changing pressures and temperatures.
Secondly, technology is becoming more automated. Bioreactors have high-performance needs as the equipment requires components that can offer repeatability through automation. Relying on manual adjustments impacts productivity as well as increases process costs.
Another major factor regards bacteria contamination from bioreactors. In cleanroom environments, contamination events can create lost batches  in cultures,  lost production time,  compliance issues,  and increased decontamination costs. Using materials that are less prone to contamination or corrosion lowers the risks of a contamination event from occurring.
The legacy design of a VA meter has simply not kept up with the changing technologies that have become available for bioreactors. Manual VA meter controls cannot handle the rapid processes that are needed in the industry while also maintaining reliability and accuracy. High-performance processes will require more automated solutions — ones which the present VA meter cannot provide.
In addition, a VA meter does not come with an output signal and they are not suitable for automatization of your process.  VA meters are extremely sensitive to changes in pressure and temperatures, and a small change in these parameters creates a relatively big error in the indicated mass flow.  This uncertainty creates non-repeatability in your process. Mass flow controllers measure true mass, independent of pressure and temperature, constantly providing an accurate gas mass flow control.

Rock Solid Mass Flow Control Improves Bioreactor Performance

Sierra’s proven line of mass flow controllers for bioprocessing meets the rigorous demands of the bioprocess industry and supports scientists and manufacturers. RedySmart mass flow controllers provide critical gas flow control systems for bioreactors to scale vaccines from lab to pilot to full-scale production.
As we know, bioreactors require precision mass flow control of the gases used to feed the biomass and to ensure proper mixing and distribution. This ensures healthy fermentation.

Smart Design

Combining superior physics, high reliability, and unparalleled flexibility, RedySmart stands apart from competitive offerings.  The RedySmart thermal mass flow meters & controllers are MEMS-based (Micro-Electro Mechanical System) technology. RedySmart thermal mass flow devices contain no moving parts and are unaffected by upstream temperature and pressure fluctuations, resulting in exceptional accuracy and repeatability.  The RedySmart offers a true OEM mass flow control solution with its modular design, cabling system, easy integration into a gas mixing block, and a wide array of digital communications options (Modbus included with no additional charge).  In addition, they are completely automated.

These design capabilities allow for smaller custom sizes that can accommodate different bioreactor sizes, including the miniaturized stirred bioreactors that are becoming the present industry trends.

Maximum Production Stability

RedySmart comes with an ultra-stable no-drift Complementary Metal Oxide Semiconductor (CMOS) sensor to assure maximum production stability required by bioprocessing OEMs. Sierra also offers a lifetime no-drift sensor warranty on the sensor. This feature provides greater production stability for bioprocessing OEMS where long term stability is key. If drift occurs, the sensor will be replaced or repaired free of charge.

Sierra also offers modular customization for bioreactor OEM designs. Many bioreactors will be manufactured to meet the specific needs of the process application. The bioreactors may require standard gases such as O2, N2 or air as well as non-toxic and non-corrosive gases. One RedySmart controller can handle up to 10 gases for just one device. Engineers can obtain flow ranges from 0 to 500 slpm (nlpm) and pressures of 3 – 160 psia (0.2 -11 bara). In addition, our gas flow controllers also handle gas and ambient temperatures ranging from 32 -122°F (0 – 50°C).

RedySmart Advantage

  • Ultimate OEM MFC-modular, compact footprint, connect power cable & communication system
  • MEMS sensor stability- Lifetime no-drift sensor warranty
  • Direct mass flow with thermal technology- no temp or pressure compensation
  • Precision electromagnetic valve control
  • Competitive OEM pricing- Cost-effective solutions
  • Built-in display-mass flow, totalizer, units, set point
  • Human & Systems Interface-local display readout, configure in field
  • Fast Set Point Control- response times as fast as +/-80ms
  • Response time: Meter (GSM): ± 80ms(3); Controller (GSC): ± 500ms(3)

Improved Accuracy

Accurate processes that can be repeated is essential for an automated, high performance bioreactor mass flow controller. Our Sierra  RedySmart MEBS-based mass flow controller offers a standard accuracy of +/- 1.0% of full scale and a high accuracy of up to ± 0.3% of full scale ±0.5% of reading. The controller also offers repeatability of +/- 0.2% of full scale. These higher accuracy ratings are due to our real gas calibration technologies for a wider range of gases.

With Sierra’s RedySmart bioreactor mass flow controller, engineers can replace their old VA meters when requiring more stability, accuracy and performance in their flow measurements. The automated features and components offer long term stability and higher performance at more cost-effective prices.