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Teledyne Hastings Instruments Blog

Benefits of a Flow Service Plan for Mass Flow Meters/Controllers

Posted by Stuart Taliaferro on Tue, Jul 05, 2016 @ 02:09 PM

Flow_Service_Plan.jpgThere are many benefits for having a Flow Service Plan for your Mass Flow Meters/Controllers.  This blog touches on just a few of them.

Maintaining calibration on measurement instrumentation is essential to minimizing uncertainties and ensuring accurate readings. Hastings Instruments offers its flow calibra­tion services featuring deeply discounted pricing. The Flow Service Plan allows the user to integrate high-quality calibrations into metrology schedules for Hastings’ 200 Series, 300 Series, and digital 300 series flow meters and controllers. The Flow Service Plan may be purchased for either new or recently reconditioned instruments.

HFC-D-302A.jpgEach instrument under the plan is eligible for three calibrations anytime within a 36-month period. Under the discount Flow Service Plan, the user purchases two calibrations and receives a third at no cost. At the time of purchase, the user may specify a calibration interval; Hastings Service will track the unit’s history and provide advance notice (four weeks) of the next scheduled calibration.

200_series_of_flow_instruments.jpgThe calibration and service department will clean, recalibrate, and ship the instrument back to the user within 5 working days or less per instrument.  The Flow Service Plan will improve up-time at the user’s facility while ensuring compliance to metrology requirements. All calibration performed at Teledyne Hastings is traceable to the National Institute of Standards and Technology (NIST).  In addition to this, calibrations are compliant to ISO 17025 requirements. 

Hastings offers a complete service department dedicated to recalibration, repair, and service for all of our mass flow and vacuum products.

If you have any questions or would like a Flow Service Plan quoted for your new or recently purchased mass flow instrument, click the button below

Interested in Service Plan

or contact your local Teledyne Hastings representative or the factory (757-723-6531 or HASTINGS_INSTRUMENTS@teledyne.com)

Tags: Flow Meter, Flow Controller

Facts You Might Not Know about Teledyne Hastings Instruments

Posted by The Teledyne Hastings Team on Thu, May 14, 2015 @ 04:45 PM

Quality Teledyne Hastings ISO 9001 CertificationLast month, we passed our ISO 9001 surveillance audit.  It has been over twenty years since we first obtained ISO and we wanted to take a step back and review some significant accomplishments.  

Teledyne Hastings Instruments rich history and customer centric vision continues to support, influence and grow with those who depend on quality process control and automation.

That's why we wanted to take a moment and celebrate a milestone with our core clients and those considering a Teledyne Hastings Instruments Flow instrument or Vacuum Gauge for the first time.


2015_Infographic_ISO_20_Years_2

Teledyne Hastings Instruments' has been providing quality thermal mass flow instruments and vacuum meters and controllers for applications ranging from academic research to space exploration for over 70 years.  Let us work with you to find the best solution for your process.

OEM, custom applications, lead time crunch, just curious:   

Contact Us

Tags: Teledyne Hastings Instruments, Flow Controller, Flow Meter, Vacuum gauge, vacuum controllers, ISO 9001 and Thermal Mass Flow, ISO 9001 and Vacuum Gauges

New! Free Teledyne Hastings Mass Flow Converter APP

Posted by Doug Baker on Tue, Aug 05, 2014 @ 02:56 PM

Teledyne Hastings is proud to offer our Mass Flow Converter app. We have created a version for iPhone, iPad, and Droid. We have also created a web-based version that you can find at www.massflowconverter.com

In this blog article, we will discuss the motivation to build the app, how it works, and how it can be used.

The first question you might be asking is: Why do we need an app to convert from one set of mass flow units to another? For instance, if you want to convert from inches to centimeters, you would just multiply by 2.54. But, converting between mass flow units is not always that straight forward. So we have developed a tool that makes it easy.

We are going to look at some examples, but first let’s review what we mean by mass flow. When we think about mass flow, it can be helpful to think in terms of the flow of individual molecules. So while flow meters are often specified by units like sccm (standard cubic centimeters per minute) or scfm (standard cubic feet per minute), the mass flow rate is ultimately about the number of molecules (n) moving through a given cross sectional area per unit time (see figure below).

 

 Cross Section resized 600

 

 

 

So as our first example, let’s take a look at the conversion of 10,000 sccm (10,000 cm3/min) to a molecular flow rate. First, we need to ask, “How many molecules are in 10,000 sccm?” In the figure below, we show a container that is 10,000 cm3 in volume. Now, before we can calculate the number of gas molecules in a volume, we must know the pressure and temperature of the gas. We can use the ideal gas law:

n = (P * V) / R*T where n is the number of molecules, P is the pressure, V is the Volume, R is the Universal Gas Constant and T is the Temperature.

 

Framed Molecules per volume

Now we need to select some given pressure and temperature so that we can calculate the number of molecules – these are called the reference conditions or the STP (Standard Temperature and Pressure). In many cases, 0°C and 760 Torr are used for the STP. But this is not always the case. So it is always very important to specify the reference conditions (STP) any time you use a standardized mass flow unit like sccm, slm, scfh, etc (any mass flow unit that starts with “s” is going to need the reference conditions or STP specified). In our example, we are going to use STP of 0°C & 760 Torr.

OK, so here we go:     n = (1 atm) * (10,000 cc) / (82.053 cc * atm / K * mole) * (273 K)

Note that we have used a value of R in terms of pressure in Atmosphere (760 Torr = 1 atm), and Temperature in Kelvin (0°C = 273K). 

n = 0.45 mole

In other words, a flow rate of 10,000 sccm (0C, 760 Torr) is the same as a molecular flow rate of 0.45 Mole / minute.

OK that is the hard way. It’s much easier to use the mass flow converter app. In the example shown above, we would dial sccm on the left and Mole/Min on the right. Then to select the reference conditions, we use the menu in the center. See Fig. 3

 Framed screen shot mass flow converter app N2 resized 600

If you are like me, you will start to play with the App. And soon you will notice that the user can change the gas using the pull down menu at the top. But notice that in the case of our first example (converting from standardized mass flow units to molecular flow units), that the gas selection has no effect on the conversion.  This is because the standardized flow units (e.g. sccm, slm, scfh, etc.) are actually molar flow units based on reference conditions (STP) and the ideal gas law.

So, why do we allow the user to select gas? In the case of units like gm/sec, Kg/hr, or lb / min, we are going to need to know the gas so that we can calculate the mass. Let’s take a look at the case of converting from slm to grams/second. We will use as our same example of 10,000 slm (0°C & 760 Torr) and we will use methane (CH4) as our gas.

We showed earlier that 10,000 sccm is a molecular flow rate of 0.45 Mole / Min.  And since 1 slm = 1000 sccm, it is easy to see that 10,000 slm = 450 Mol/min. And since we know that our unit of choice (gm/sec) is in terms of seconds, let’s go ahead and convert our time units now:

10,000 slm = (450 Mole / Min) * (1 Min / 60 sec) = 7.5 Mole/ sec.

Now we need to know how much mass there is in a Mole of methane. Google is very nice for getting this number – just type, “Molecular weight of methane” and here is the result:

 

Framed mass flow converter app google screen shot resized 600 

 

By the way, Google will do this for almost all gases. So now we can finish our conversion and we get:

 

7.5 Mol / sec * (16.04 g/mol) = 120 g/sec

 


Framed mass flow converter app screen shot CH4 2 resized 600 

 

The mass flow converter app and website www.massflowconverter.com takes all the work out of these conversions and we hope that you will find this tool helpful. If you have any questions about mass flow meters and controllers, Application Engineers at Teledyne Hastings are always happy to help.

Tags: Teledyne Hastings Instruments, Flow Controller, mass flow conversion, Mass Flow Calculator, Mass Flow Range, Gas Flow Range, Mass Flow, Flow Meter, units conversion

FAQ Corner – Specifying range, pressures on Mass Flow Instruments

Posted by Wayne Lewey on Wed, May 29, 2013 @ 10:01 AM

We often see the label “One Size Fits All”.  This may be fine for some consumer goods.  However, it can be quite problematic when applied to items like shirts, gloves, or even golf clubs.  “One Size Fits All” also does not work for Mass Flow Controllers (MFC).  Not all applications are alike.  Forcing a “One Size Fits All” MFC into an unsuitable application can squander accuracy and induce valve failure.

Why do you need to specify the gas flow range on a MFC?  The Full Scale (FS) Range and Gas on a MFC directly correlates to the transmitted output (analog or digital) of the device.  In an analog device, the maximum output value (such as 5 vdc or 20 mA) will be equivalent to the FS value.  The accuracy of most MFCs is a function of this FS Range.  For analog devices, it is commonly ±1% of FS.  For digital devices, it is commonly published to be ±(0.5% of Reading + 0.2% FS).  Selecting the FS Range close to an application’s maximum flow rate optimizes accuracy for that specific application.  This is a good practice.  In addition, the gas must be specified.  Most MFCs use thermal based sensors.  These sensors actually measure the molecular flow rate rather than the mass flow rate.  Various gas molecules transfer heat differently, and thus the gas must be known.

Why do you need to specify Upstream Pressure and Downstream Pressure on a MFC?  Again, not all applications are the same.  A “One Size Fits All” MFC is typically not set up for applications at high pressure, low pressure, high differential pressure, or low differential pressure.  The definition of high and low will also fluctuate from one user to another.  Teledyne Hastings Instruments selects and tests MFC valve components (orifice, spring, etc.) that optimize valve stability for the exact application pressure conditions.When using a Teledyne Hastings Instruments MFC, you will always find the FS Range / Gas and the Upstream / Downstream Pressures listed on the serial number label.

Sample Calibration Sticker for MFC

 

Wayne Lewey was first exposed to mass flow controllers while an undergraduate at North Carolina State University (Chemical Engineering).  Today, Wayne is the International Sales Manager at Teledyne Hastings Instruments and can be reached at wlewey@teledyne.com.

Tags: Teledyne Hastings Instruments, Flow Controller, pressure, range, differential pressure, mass flow controller, Gas Flow Range, mass flow meter

FAQ Corner – What is the Importance of STP Conditions on Mass Flow

Posted by Brandon Hafer on Thu, Mar 07, 2013 @ 03:19 PM

As I go through the day looking at various mass flow applications, I often notice that it is very easy for users to overlook one of the crucial items required for calculating mass flow. Looking at an application with its established requirements, we often jump right to determining “what flow rate is required?” However, it is important to remember that mass flow applications using volumetric units must reference a standard temperature and pressure. But why is this the case?

When examining liquid flow instruments, we know that liquids are incompressible and thus the amount of a substance present is determined by the volume being used. This leads to a simple calculation using density with the already determined volume to find the mass present in the volume or the volumetric flow.

GAs molecules @ STP Gases, however, ARE compressible and so the volume is only one factor in determining the amount of material being measured. If we look at the ideal gas law that you may remember from a chemistry class school (PV = nRT), we understand that temperature (T) and pressure (P) must also be considered in the equation. Otherwise it is impossible for us to know “how much” of the substance (n) there is in the space (V) or flowing through the system.

But given all of this information do we actually end up with the mass flow? The actual quantification of this “how much” calculation is expressed in moles (n), which is an extremely large number of molecules of a gas stated as Avogadro’s number, equal to 6.02x1023 (Don’t be scared by this value, though. A mole is a number, just like one dozen is 12, so one mole is 6.02x1023 molecules). Since the number of molecules of a gas and the mass are directly related for each gas type (i.e. molar mass), we are able to calculate the mass of the volume or volumetric flow based on the number of moles present. This is based on the assumption that the measured gas is pure and not contaminated with any other gases.

We’ll look at an example of the difference of STP conditions in a mass flow meter.  Teledyne Hastings Instruments assumes STP of 0°C and 760 Torr, but would prefer the customer to specify their STP conditions for the application. We will use the frequently referenced STP of 20°C and 760 Torr for the second part of this example. Suppose that we are looking to  measure 1 SLM (Standard Liter per Minute) of Nitrogen gas. As I’ve discussed earlier, the 1 SLM must be referenced to an STP value, so we will use our assumed conditions of 0°C and 760 Torr. If we were to change to the second set of conditions, the number of moles present in the flow (Molar Flow Rate) would change, and our mass flow rate would thus change (based on the direct relationship between mass and moles). Our initial mass flow rate of 1 SLM of Nitrogen at 0°C and 760 Torr would now be 1.074 SLM of Nitrogen at 20°C and 760 Torr.

Mass Flow Meter  Mass flow controllerAn important item to note is that the STP conditions are not actually present during the calibration of mass flow meters and mass flow controllers. Gas conditions are not brought to 0°C and 760 Torr prior to running calibration of equipment. The substance may not even be in gas phase at 0°C. The STP conditions are simply stated to define the standard volumetric flow rates of a substance IF it were an ideal gas at standard conditions.

This is also the reasoning for the addition of the “S” or “Standard” at the start of the stated volumetric flow rate (e.g. Standard Liters per Minute (SLM) or Standard Cubic Centimeters per Minute (SCCM)). We are stating the volumetric flow that would be present using standard conditions. So, using the information that we learned earlier, by stating the units in Standard Volumetric Flow Rate we are actually stating the Molar Flow Rate. This information changes based on the standards we are referencing and emphasizes the importance of stating the required STP conditions.

We welcome your comments and your questions about mass flow. Please complete the form below:

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Brandon Hafer is an Application Engineer with Teledyne Hastings Instruments. He completed his undergraduate degree studying meteorology at the Pennsylvania State University before serving as an officer in the United States Navy. He received his master’s degree in Systems Engineering from George Washington University and has been with Teledyne Hastings Instruments for two years. If you would like to contact him, he can be reached at brandon.hafer@teledyne.com.

Tags: Teledyne Hastings Instruments, Flow Controller, Flow Meter, STP, Thermal Flow, Standard Temperature and Pressure