Fluid: Density and viscosity
We always have questions about the fluid such as gas or liquid.  What are the density and viscosity?  Is it corrosive or opaque?  If it a know fluid such as air, nitrogen, water, etc.  The questions get much easier because the world has defined how these known fluids behave so we can easily determine density and viscosity for common fluids such as air, water, nitrogen, etc.  Which leads to the questions as to why do we need to know fluid density and viscosity?  Fluid density and viscosity are important because these two values allow us to select the right flow meter (meter size).  We call this sizing.  What is behind sizing?  Briefly, performance data has been collected on all of the different meters we offer.  We query the performance data and look for flow meters that fit the supplied process conditions (density and viscosity).  Usually there are many flow meters that fit your conditions.  From there it becomes a matter of preference, available options, price or accuracy.  This leads me to my last topic on VA meters, which is accuracy.

Accuracy                                                                          
There are other flow measurement technologies that are more accurate than variable area but variable area is still widely used.  VA flow meters are made in all shapes, sizes and types of materials. It has so many positives such as no power needed, easy to install and use and very repeatable which brings me back to accuracy versus repeatability.  Variable area  accuracy is computed using the full scale accuracy method rather than accuracy of reading.  Simply said the variable area flow meter is much more accurate in the upper end of the flow range.  But more VA meters are used for repeatability of flow measurement.  This means given the same process conditions the float will “repeat” and be at the same scale reading.

In conclusion, correctly specifying a variable area flow meter does require several questions to be answered but as always the intent is to get the best product fit for the application.

Learn more about the variable area flow meters that Brooks has to offer here.

3. Flow rate – minimum, maximum, normal
Of course flow rate is an obvious requirement but it is more complicated than it appears.  The goal is to specify a VA meter where the normal operating flow is in the 60% to 80% of the meter’s range.  Why you ask because a variable area meter is more accurate in the upper part of its range.  I will talk more about accuracy in my next blog post.  Of course a flow meter needs to be chosen that handles the minimum and maximum flows too.  The other component of flow rate is the units.  If the unit is too small or too large for the meter selected the flow number can be miniscule (many zeros to the right of the decimal point) or too large (many zeros to the left of the decimal point).  An example would be l/d (liters per day) for a 4” meter.  The maximum flow rate of the meter would be almost 2,400,000 l/d wow that is a lot of something but not very practical on a VA meter scale.  This occurs on very low flows an example would be 0.0006 cf/s (cubic feet per second).  In both of these cases considering a more appropriate unit is necessary.

4. Reference conditions and volumetric flow type, if a gas
A component of flow rate is the reference condition and flow type.  These only apply to gases.  My views on these two things are” don’t worry about it”.  Why you ask? because you can count on one hand how many people want actual volumetric gas flows.  This is extremely unusual.  The reference condition can be a variable but customers know what they need and they usually tell us.  The two “biggies” are standard in the US and normal which is very common in the rest of the world.  US standard reference condition is 70°F and 1 atmosphere.  The normal reference condition is 0°C and 1 atmosphere.  Simply this is a method to correct the flow rate to a standard.  It is important but don’t lose sleep over it.

I’ll wrap up my tips for specifying a VA flow meter in tomorrow’s post where I’ll focus on fluid density and viscosity as well as accuracy.

VA meters reacting to changes in process conditions can be a good or bad thing based on a user’s viewpoint, which brings us back to the real question.  So why do we need so much information to specify the proper VA meter?  I will go through the questions and explain why it is necessary.  The information needed is:

1. Normal operating temperature & pressure
2. Maximum operating temperature & pressure
3. Flow rate – minimum, maximum, normal
4. Reference conditions and volumetric flow type, if a gas
5. Fluid: Density & viscosity
6. Accuracy

1. Normal operating temperature & pressure
What are the normal operating temperature and the maximum operating temperature?  When the fluid is a gas or some liquids it is absolutely necessary to know the operating temperature because of the impact to fluid conditions (density and viscosity).  The maximum temperature is necessary because many times the operating temperature is much lower than the maximum temperature.  A great example is selecting a plastic meter based on the operating temperature but then realizing the maximum temperature far exceeds the capability of the meter.

2. Maximum operating temperature & pressure
What are the normal operating pressure and the maximum operating pressure?  Again when the fluid is a gas it is absolutely necessary to know the operating pressure because of the impact to fluid conditions (density and viscosity).  I have seen applications where the maximum operating pressure was so high that we didn’t have a suitable meter even though the normal operating pressure was quite low.

Tomorrow’s post will dig into how important flow rates and reference conditions are in specifying a variable area flow meter.

Brooks Instrument’s Ed Fisher, who is our inside expert on all things DLI Vaporizer, gives you a tour of a direct liquid injection vaporizer system that we built for a customer. There were actually three of these units shown in the video. The sound isn’t that great, so I apologize for that in advance.

In part three, Ed finishes explaining this massive DLI Vaporizer system.

Missed part one or part two? Be sure the check them out!

Part 2

Part 1

A little about Miller Energy: Miller Energy in Exton, PA is an industry leading manufacturers representative and distributor of process controls and instrumentation. Founded in 1958, with offices in South Plainfield, NJ and Exton, PA, Miller Energy has been serving the area for more than 54 years. Covering the refining, power generation, industrial gas, chemical and petro chemical, food and beverage, water and wastewater, pharmaceutical and biotech industries, Miller Energy leads the Northeast in measurement and control solutions.

A little about Webco Controls: Webco Controls, established in 1986, is a manufacturer’s representative specializing in precision flow measurement, control and calibration equipment. Covering the Easter PA, Southern NJ, and DE geography, Webco Controls has offered a broad range of measurement and control solutions including Brooks Instrument (of course!), Daniel Measurement, and Brodie Meter Co.

For more information, visit www.MillerEnergy.com.

Brooks Instrument’s Ed Fisher, who is our inside expert on all things DLI Vaporizer, gives you a tour of a direct liquid injection vaporizer system that we built for a customer. There were actually three of these units shown in the video. The sound isn’t that great, so I apologize for that in advance.

Part two talks about some of the safety features and some of functionality of the DLI Vaporizer system.

Click her to view part three.

Missed part one! Click here.

1954

We had 5 winners that will be receiving a 4GB memory stick in the shape of a Brooks GF40/80 Series mass flow controller/mass flow meter.

Happy New Year everyone!

Brooks Instrument’s Ed Fisher, who is our inside expert on all things DLI Vaporizer, gives you a tour of a direct liquid injection vaporizer system that we built for a customer. There were actually three of these units shown in the video. The sound isn’t that great, so I apologize for that in advance.

Part one gives you a general overview of the system and components.

Click here to view part 2.

Delivering saline solution to a clinic for medical needs … sounds simple enough, right? Not when that clinic is on the International Space Station, the moon or even Mars. Transporting medical fluids that are manufactured on Earth into space is expensive and logistically challenging. NASA Johnson Space Center knew there had to be a way to manufacture medical fluids in space to alleviate the transportation problems and to make spacecraft more self sufficient, so they called on the microgravity science expertise and spaceflight hardware development know-how of Cleveland, OH based NASA Glenn Research Center and ZIN Technologies, Inc.

ZIN Technologies engaged Brooks Instrument to help solve this unique flow challenge. V-F Controls, Brooks Instrument’s sales representative in Mentor, OH, recommended the Quantim Coriolis mass flow controller. This mass flow controller would be ideal to measure the water flow through a purification system to a standard IV bag that was prefilled with salt crystals and a magnetic lab stirrer.

“We chose the Brooks Quantim mass flow controller because of its accuracy at the low flow range the application requires,” stated Dan Brown, ZIN Technologies. “Plus, the Coriolis mass flow technology was previously tested by NASA and had already been shown to work in reduced gravity.”

This isn’t the first time Brooks products have contributed to the space program, though. In the 60s Brooks Sho-Rate variable area flow meters (rotameters) were used to leak test space suites. And in the 90s, after the Challenger disaster in 1986, Brooks thermal mass flow meters were used to leak test the space shuttle o-rings. Now, Brooks Quantim Coriolis mass flow controllers are making their way into space to ensure that astronauts have medical fluids on demand for emergency needs.

Construction features of the Quantim mass flow controller are critical in this application because not only does it need to work in zero gravity, but spaceflight electronics also typically must pass a rigorous 6.8G RMS workmanship vibration test. The standard Quantim Series proved to be rugged enough for the vibration levels and the long trip to the space station.

An initial prototype of the medical fluid generation system called IVGEN (IntraVenous fluid Generation) is currently being installed into a laboratory glove box on the station. The prototype consists of an accumulator for pumping potable water, a filter unit with the Quantim mass flow controller installed, a data collection and control unit, a mixing module, and an IV bag with salt crystals. In operation, potable water is transferred into a bladder inside the accumulator. Nitrogen is pumped into the accumulator forcing the water through the mass flow controller, then through a series of filters, and into the IV bag. The flow rates range from 15-25 mL/min and accuracy is very important in the application. The results from the first test conducted on the station will be returned to Earth and tested for proper filtering and mixing with the salt crystals. Once IVGEN is proven to be successful, the system will be scaled accordingly to meet the requirements of manned missions to the moon and Mars.

This reminded me a of a blog post I wrote about a year ago about some of our SLA mass flow controllers supporting NASA research. The mass flow controllers are part of a gas mixing system and chamber that will simulate high thermal stress and the planet Venus’ corrosive atmosphere to test  a new exploration module.

We also had a success story back in 2009 with our Quantim Coriolis mass flow controllers being sent into space via the International Space Station. In this application, the Coriolis mass flow controllers are being used in a process to manufacture medical fluids in space.

And in the 90s, after the Challenger disaster in 1986, Brooks thermal mass flow meters were used to leak test the space shuttle o-rings. It seems that Brooks has a good track record of working with NASA!

I personally found it very interesting and proud, to be honest, that Brooks has helped out the space program in so many ways with three of our product technologies. So, this old Norman Rockwell oil painting will find a nice home in our Hatfield, PA offices, maybe it will be right next to my desk.