Tag Archives: Gas Mass Flow Control

SmartTrak® 140 Ultra-Low ΔP Mass Flow Controllers

Get Incredible 4.5 psid (310 mBard) at Flows up to 500 slpm. When you need precision gas mass flow control of expensive process gases, where minimal pressure drop is a key consideration for cost savings and efficiency, the SmartTrak® 140 flow meter controls up to 500 slpm with an ultra-low ΔP of 4.5 psid (310 mBard) much better than typical ΔP values of 25 psid (1700 mBard) for equivalent mass flow controllers on the market.

  • Control 10 sccm to 500 slpm (nlpm) with 4.5 psid (310 mBard)
  • Competitively priced compared to other high flow controllers
  • Controls up to 500 slpm (nlpm) with an ultra-low ΔP of 4.5 psid (310 mBard)
  • Control valve with large flow coefficient (Cv) for precise digital PID control at low ΔP
  • Dial-A-Gas® Technology allows control of 10 pre-programmed gases in one instrument; substitute any gas
  • Pilot Module gives the customer a remote or local display and ability to change gas, engineering units, output signal, full-scale, set point, zero, span
  • All 316 stainless steel construction for increased durability
  • Patented, inherently linear Laminar Flow Element (LFE) for true linear performance

Learn More…

SmartTrak MFC Highlighed on NOVA TV Program

Research Advancements with Flow MetersIt’s alive! No, I’m not talking about Dr. Frankenstein’s monster. But you’d be surprised by what researchers have discovered in the area of therapeutic hypothermia, or using hydrogen sulfide to slow the body’s demand for oxygen.

A recent episode of NOVA, “Making Stuff Colder,” highlights research being conducted by Mark Roth, a biochemist for the Fred Hutchinson Cancer Research Center. Roth has discovered that hydrogen sulfide slows the brain’s demand for oxygen in extreme cold, which can be beneficial for trauma patients susceptible to oxygen deprivation.

In studies with rats, Roth can actually bring the rats “back to life” after reaching hypothermia with optimal amounts of hydrogen sulfide. Roth hopes to duplicate this process with people in trauma situations, effectively saving thousands of lives by delivering hydrogen sulfide intravenously and decreasing the need for oxygen.

As shown in the video,  Roth and his team relied on Sierra’s SmartTrak 100 mass flow meter to accurately measure the gases used in the testing process. See the SmartTrak in action in the NOVA video below (frame 18:32):

Wondering how a mass flow meter could positively impact your research? Contact us for more information.





Gas Mass Flow Control: Why Thermal Mass Flow Technology is Recommended for Best Accuracy

It’s no secret. Price, but perhaps more importantly, performance, drive every new product acquisition you make. How important is measurement accuracy and control to your lab experiment or industrial process? It’s critical. If your flow readings are off or the flow is not controlled with precise accuracy your research is compromised, product quality suffers, and processes loose inefficiency.

So What Type of Flow Meter Technology Should You Choose for the Highest Accuracy?

Competitive “indirect-type” mass flow measurement technologies—like differential pressure devices that boast speed as the most important factor—can only measure volumetric flow and must calculate mass flow. However, thermal mass flow technology is an industry standard for mass flow control of gases because it measures flow directly, at the molecular level. In essence, counting and controlling every gas molecule flowing through the instrument to achieve unmatched precision.

The molecular mass or weight of the flowing gas is what you really care about to optimize your flow process. Because thermal mass flow controllers measure gas mass flow rate directly, they remain unaffected by temperature or pressure effects. It doesn’t matter how hot or cold the gas is or what pressure fluctuations may be happening upstream. You always get smooth, steady, accurate and extremely reliable gas mass flow rate delivered where you need it, every time.

For over 40 years, Sierra has pioneered the development of precision gas mass flow controllers (MFC). Today, the breadth and depth of our high-performance SmartTrak mass flow controller lineup, with over 100,000 successful installations, proves we’ve never let up. Experience our passion for mass flow control.

Download the User’s Guide to Thermal Mass Flow Controllers

How Do MEMS Mass Flow Controllers Work?

Not All MFC Sensor Technology is Created Equal

Mass flow controllers offer precision gas flow control to many critical industries including biopharm, semicon, food & beverage, manufacturing, and R&D. As the technology demands increase in these sectors, so does the demand for precision gas flow control systems. The more accurate and repeatable the gas flow control the better the yield, the higher the product quality and the lower the cost in wasted materials.

So what mass flow control technology offers the highest accuracy and repeatability over time? MEMS (Micro-Electro Mechanical Systems) sensors offer the most stable and accurate gas flow control in the industry. Mass flow controllers and meters based on MEMS technology don’t drift like other technologies, offering OEMs and bioprocessing applications a mass flow controller that is accurate over the lifetime of the device-no yearly recalibration or process shutdown necessary.

How does MEMS technology work to ensure a “no-drift” mass flow controller?

MEMS Principle of Operation

MEMS technology utilizes an advanced, ultra-stable, no-drift CMOS (Complementary Metal Oxide Semiconductor) sensor. The CMOS sensor houses both the electronic circuits and mechanical elements on a silicon chip, similar to the process used for integrated circuits.

Sierra’s RedySmart MFC – MEMS Sensor at 50x Amplification view

MEMS technology is based on the thermal principle of operation. MEMS sensors consist of two or three temperature sensors and a heater. Through vapor deposition, an extremely small molecular layer is deposited on a thin membrane. MEMS-based mass flow controllers have a bypass that pushes a defined percentage of the total gas flow through the sensor. The bore of the sensor is fairly large, so that the pressure drop is relatively low. In the presence of flow, the MEMS chip introduces heat into the medium with a constant heating output. The two temperature sensors are arranged symmetrically before and after the heating element to detect a shift in the temperature profile towards the downstream sensor of the heating element. If there is no flow, both sensing elements measure the same temperature. Because the sensor is part of the MEMS electronic circuit, the measured signal is immediately digitized giving direct mass flow readings.

Why Mass Flow is Critical

Measuring mass flow is important since most processes are more directly related to mass flow rather than to volumetric flow. For respiration, fermentation or any chemical process, it is that number of oxygen molecules that are critical, mass not volume that is critical. Unlike turbine meters, ultrasonic, pressure differential, pitot tubes and many other devices, thermal flow meters measure mass flow. Direct mass flow meters are unaffected by fluctuations in both temperature and pressure which make them inherently more accurate than volumetric technologies.

Benefits of MEMS Mass Flow Controllers

The biggest advantage of the MEMs sensor is that there is no (measurable) drift. Drift is a slow shift of the zero and the measured value at a given flow. Drift affects the accuracy. MEMS sensors are also compatible with its electromagnetic (EM) environment and don’t emit levels of EM energy that cause electromagnetic interference (EMI) distorting the signal. This along with the fact that the sensors are free of mechanical and thermal stress enables a no drift sensor and long-term device accuracy.

Mass flow controllers based on MEMs technology do not have a linear output, so they must be calibrated with the actual gas that is being used in the application. The output is a complex curve that can only be accurately curve-fit with a spline or a polynomial. And every sensor construction varies, so there is no repeatability from sensor to sensor. That means that every flow meter and controller needs to be calibrated individually on actual gas which increases their accuracy.

MEMS sensors are also very fast with a 50 msec response time with virtually no warm-up time. The instrument does not need the zero to be adjusted on regular basis. A MEMS sensor is also a lot more sensitive and due to that a turndown of 1000 : 1 is obtainable.

Benefits of MEMS Sensors

  • No-drift sensor-Long term stability over a long period of use
  • Wide turndown of 100:1. (Higher possible)
  • Less sensitive to pollution due to big ID sensor
  • Excellent temperature coefficient
  • High accuracy due to real gas calibration
  • Low-pressure drop (2.5 mbar at low flow)
  • Built-in flexibility
  • Low power consumption

RedySmart Mass Flow Controller with Lifetime No-Drift Sensor Warranty

Sierra’s RedySmart thermal mass flow meters & mass controllers are based on MEMS-based (Micro-Electro Mechanical System) technology to complement our SmartTrak® capillary-based mass flow meters & gas controllers. RedySmart thermal mass flow devices contain no moving parts and are unaffected by upstream temperature and pressure fluctuations, resulting in exceptional accuracy and repeatability.

RedySmart Proven & Stable Mass Flow Controllers offer OEMS:

  • Lifetime no-drift sensor warranty – if drift occurs, instrument will be repaired or replaced free of charge
  • High Accuracy up to ± 0.3% of full scale ±0.5% of reading
  • Repeatability of +/- 0.2% of full scale
  • Air, N2, O2 are standard. Other non-toxic, non-corrosive gases available upon request.
  • Custom and compact gas mixing blocks
  • MEMS (Micro-Electro Mechanical Systems) with ultra-stable no-drift CMOS (Complementary Metal Oxide Semiconductor) sensor
  • Ideal for OEM Applications-optimized for BioPharm/Burner Control
  • Modular-customize to needs. An easy-connect communication and power cable system has been designed for ultimate flexibility

Learn more about MEMS Sensor technology and RedySmart products.

Discover how MEMS sensor technology is providing edge to accelerate bioprocessing from pilot to production.

Assess Your Flow Meter Options with Simple Selection Charts

There are many mass flowmeter and mass flow controller options available. As you sort through the wide variety of styles, sizes and prices, you may be wondering which flow meter is the right fit for your application. In reality, more than one may meet your flow range needs. Now what?

Let me introduce you to Sierra’s new, user-friendly flowmeter selection charts. Each one categorizes our instruments by flow rate, as well as other special attributes and features you may be looking for.

So, if you’re evaluating your flowmeter options, I encourage you to check out our mass flow meter chart or mass flow controller chart.

Ammonia Gas Flow Measurement Challenges & Solutions

Measuring and controlling ammonia can be tricky. One mistake during the transition from gas to liquid and your instrumentation is ruined. In the video below, Glen Coblentz, Vice President of North American Sales, gives some tips for successful mass flow measurement and control of ammonia. It could mean the difference between success and a costly mistake!

What challenges have you had measuring or controlling ammonia?

Video Transcript

Hello, Glen Coblentz from PITTCON 2012 again. We’ve had many people stop by the booth this week, wanting to measure or control ammonia flow. We’ve got a perfect product for that.

There’s a couple precautions that you have to take. And some of the customers that have stopped by have run into the problems of the ammonia going from gas to liquid, ruining the mass flow controller they currently use, et cetera.

The C100 works great on ammonia. It is not one of the 10 preprogrammed gases, but an easy gas substitution. We’ll put the ammonia into the C100, it’ll work fine.

But the key with ammonia is it’s got to be dry, and it’s got to be very warm. The max spec on this is 122F, and we recommend heating the tube, the gas tubes coming into it and out, to at least 115 and also getting a hot plate under your meter or controller and warming up the stainless-steel body to about 115.

If you take all of those precautions, you’re going to be able to measure ammonia gas flow for years and years with no problem. Thank you.

Learn More Ammonia Do’s and Don’ts

Primary Standard Gas Flow Calibration—The Only Guarantee of Accuracy


Calibration facility

At Sierra, we have a saying: “An instrument’s accuracy is only as good as its calibration.”

The accuracy of your mass flow controller (MFC) is essential in assuring the efficiency, performance, and quality of your flow meter. In many cases, if your instrumentation is not calibrated, then a decline in performance is possible due to sensor drift from the factory calibration. Various things cause drift: dirt buildup, aging of the electronics, physical changes in the sensor, etc.

To make sure your MFC is reading at the accuracy you specified at purchase, many users recalibrate or validate flow meter or MFC  annually. In some industries, assuring your flow meter’s accuracy is required by either corporate policy or government regulations like EPA, FDA, MACT mandates. There are many ways to calibrate MFCs to assure accuracy including transfer standards, but the best way is a primary standard calibration.

Primary Standard = Precision Calibration

Only primary standard gas flow calibration systems deliver world-class levels of accuracy and traceability.

Here is what to look for in mass flow meter primary standard calibration:

  1. Primary standards are characterized by the basic quantities of time and distance, while transfer or secondary standards, such as laminar flow elements, are calibrated against another device, generally another flow meter. Primary standards can also be verified by every national laboratory.
  2. The calibration standard should be NIST traceable standard accuracy, better than 1% of full scale.
  3. The most accurate primary standards adhere to the NIST “rule of four.” This means the gas flow primary standards are required to be four times more accurate than the device under test. This “rule of four” needs to be a requirement for any factory calibration or calibration house.
  4. Flow meter calibration is both a science and an art–look for expertise in flow meter manufacturing or flow meter calibration. In reality, the manufacturing factory not a third party calibration house, will give the very best flow meter calibration due to the flow calibration core competency and working knowledge of the meter.
  5. Facilities should be ISO 9001 certified and/or ISA 17025 & NAVLAP compliant.

Sierra is one of few manufacturers today that performs a detailed 10-point calibration across the entire mass flow range. We strictly adhere to using primary standards and the NIST “rule of four.”  Sierra’s SmartTrak mass flow controller is a prime example of this. SmartTrak’s NIST-traceable standard accuracy is better than 1% of full scale. We offer even better accuracy–as good as half a percent of full scale upon request.

Learn more about utilizing Sierra’s SmartTrak mass flow controller for your next project. Over 100,000 installed SmartTrak mass flow controllers can’t be wrong. And SmartTrak’s unmatched accuracy and performance is guaranteed with a lifetime warranty.

Discover The Swiss Army Knife of Mass Flow Controllers

How Do Biopharm Mass Flow Controllers Optimize Bioreactor Performance?

Our new bioreactor application tech note is worth the download. The new tech note focuses on how digital mass flow controllers optimize bioreactor performance and replace manual variable area (VA meters) with an integrated valve to control the gases in their bioprocesses to yield greater results.

As you know, in today’s climate it is a race against time to create viable vaccines from pilot to scalable vaccine production to fight infectious diseases. In the biopharma world, the efficiency and productivity of bioreactor technology becomes a critical path to this vaccine development.

Learn how MFCs optimize bioreactor performance and check our four tips for selecting the perfect biopharma mass flow controller by downloading the “How Digital Mass Flow Controllers Optimize Bioreactor Performance” application tech note.



Precise PVD with Mass Flow Meters

Developers and manufacturers of solar photovoltaic installations have seen a dramatic increase in business in recent years. If you’re part of this industry, you know that solar energy now generates power in more than 100 countries and continues to be the fastest growing type of electricity generation in the world. Due to the growing demand, Photovoltaic Panelsmanufacturing of solar cells and photovoltaic arrays have advanced significantly.

Physical vapor deposition (PVD) or sputtering is commonly used for creating the films used to construct photovoltaic panels. Precise gas mass flow rate to the vacuum chamber is critical during the PVD process. Since there is so little pressure drop to work with, PVD processes require flow control devices that are relatively insensitive to the absolute pressure in the chamber.

That’s where mass flow controllers and flowmeters come in. Unlike differential pressure devices (dP) like orifice plates, which require a large pressure differential to operate efficiently, mass flow sensors are ideal for the PVD application because of their unmatched precision and reliability.

If you’re not using a mass flow meter with your PVD processes, chances are you are not achieving the level of accuracy you need. Consider making the switch!

Best Practices for Mass Flow Controller Selection & Installation

Mass Flow Controller Best PracticesAs scientists, facilities managers and manufacturing engineers, specifying equipment is a part of our daily work life. What product do I need? What’s the best price for the value? How do I install the product once I get it? The more information about best practice principles, the easier the job is of specifying and buying equipment. Through our years of experience of specifying, installing, and servicing mass flow controllers, we have compiled a comprehensive list of best practices by users for the selection, safety, installation, and operation of their thermal mass flow meters and controllers are as follows:

Best Practices-Product Selection
1. Select only those mass flow meters and flow controllers where the manufacturer’s specifications meet the conditions of the application, such as maximum and minimum flow rate, pressure and temperature. Some manufacturers have software programs that recommend the instrument model best suited for your application.

2. To minimize pressure drop and flow non-uniformities, you should select the instrument with the largest inlet fittings compatible with the size of the process line. In the case of corrosive gases, the instrument selected should have materials of construction that provide protection against corrosion.

3. Size the instrument so it operates in the upper two-thirds of its full scale mass flow rate range.

Installation and Set-Up

4. Install the instrument only in process lines that meet the manufacture’s pressure and temperature ratings. A margin of safety should be provided if spikes and surges exist in the process. Proper pressure relief valves and burst plates should be installed in high pressure applications.

5. To avoid obstructions in the sensor tube and the narrow flow channels in the laminar flow element, you should install the instrument in process lines that have clean gases. Upstream particulate filters properly sized for the flow rate, with a minimum rating of 5 microns are recommended for all applications.

6. To avoid thermal siphoning (or, the so-called, “chimney effect”), you should install the instrument in the process line with the axis of the flow body oriented horizontally, not vertically. At zero flow, if the axis is vertical, the gas heated by the sensor tube rises upward through the sensor tube and creates a closed flow loop in the flow body that causes the instrument to read a flow rate when there is none. This effect is significant only in the very lowest portion of the full scale range. If system constraints require vertical mounting, then the instrument should be re-zeroed in the field. Vertical mounting requirements should be communicated to the manufacturer upon order so the instrument can be adjusted to meet these special requirements.

7. To avoid stress on the springs in the control valve, particularly in medium- and high-flow mass flow controllers, you should install the instrument in the process line with the axis of the flow body oriented horizontally as required above and, additionally, with the control valve located on top of the flow body, not on the bottom or the side. If system constraints require a different instrument orientation, you should communicate this requirement to the manufacturer upon order so that adjustments can be made.

8. After turning on the instrument, you should allow the instrument to warm up for the time period specified by the manufacturer. A warm-up time of about 10 to 30 minutes typically is required for the instrument to reach full accuracy.

9. Be sure to zero your mass flow meters and controllers prior to first use and periodically afterward on a schedule based on the manufacturer’s recommendations or your own experience. The zero flow output signal should be averaged over a sufficient time interval. Preferably, zeroing should be performed with the actual gas to be measured at the same pressure and temperature of the application, or close to it. If there is a change of gas, the instrument should be flushed with the new gas before being zeroed. Obviously, for proper zeroing, the flow rate must be zero. This is best accomplished, in the case of controllers, by commanding the control valve to be shut, and, in the case of both mass flow meters and controllers, by closing shut-off valves installed just upstream and downstream of the instrument. In the absence of these valves, the process line must have other means to insure that the flow is zero.

Following these best practices are sure to result in the most accurate measurement outcome with your new mass flow meter or controller. Have any other tips we didn’t mention or questions about mass flow control? Please leave them in the comments section below.