Have questions? Need Help?
757.723.6531 | 800.950.2468

Teledyne Hastings Instruments Blog

Women's History Month - Celebrating Mary Hastings

Posted by Doug Baker on Mon, Mar 08, 2021 @ 10:00 AM

Mary HastingsMarch is Women’s History Month and this year we’d like to focus on Mary Hastings, one of the key founders of Hastings Instruments. Mary Comstock graduated from William & Mary with a degree in physics with minors in math and chemistry. She was truly a pioneer in many ways. After college, she took a job as a “computer” at NACA (National Advisory Committee for Aeronautics) in Hampton, Virginia. There, Mary met Charles Hastings, a young engineer who had his office across the hall from her. The two were married in 1940.

In a business era that was almost thoroughly dominated by men, Mary was an invaluable contributor to the success of Hastings Instruments. She promoted the fledgling company through press releases that she prepared for local papers and thereby helped to secure critical financial support. She attended shareholder meetings of other companies to learn how they conducted their annual meetings. For many years, Mary prepared the annual report for Hastings shareholders. In short, she was not afraid to tackle any challenge that would help grow the company. Moreover, Mary was a constant voice of wisdom to her husband with respect to company decisions and policy. She accomplished all of these things while the couple raised three children.

It is reasonable to assume that without Mary Hastings, the company would not have been nearly as successful. So during Women’s History Month, we want to celebrate her many accomplishments. You can hear more about Mary from her daughter Carol Hastings Sanders in this video:

https://www.youtube.com/watch?v=AxdFQQXEEzQ

Carol Hastings

 

Tags: Teledyne Hastings Instruments

Prosperity Years 1951-1953 - Part 4 Teledyne Hastings History

Posted by The Teledyne Hastings Team on Fri, Jul 26, 2019 @ 03:17 PM

Newcomb Avenue Location 1951The early part of the 1950’s was prosperous for Hastings due in part to the demand for the Raydist and large military contracts as a result of the Korean War. Sales nearly tripled between 1950 and 1953 and there were almost 200 employees.  Hastings had outgrown its space yet again and expanded to a 14,000 square foot building on Newcomb Avenue (current day location for Teledyne Hastings).  The building was originally used as a car barn for street cars, then as a World War I armory and eventually as a manufacturing plant for ladies clothing.

 

With the new location, other changes were happening as well.  Hastings entered into a joint venture to supply Raydist services for the petroleum industry in the Gulf of Mexico thus creating Offshore Raydist, Incorporated. Another company was formed out of Hastings at this time, Raydist Navigation Corporation (RNC).  RNC was set up to handle the leasing of Raydist equipment outside of the Petroleum industry.

 

During this period, most of the focus was on Raydist and trying to establish itself in new fields.  One area was to have the Raydist on the S.S. United States.  This superliner promised to be the fastest passenger liner in the world and would serve as a troop transport in the event of war.  Because of personal relationships, Hastings could test and prove that Raydist was the superior system of conducting the tests at a measured-mile course.  The test would use a specially-designed buoy which could be cast overboard and allowed to float freely during the trials.  The relay equipment would be installed in the buoy, while the S.S. United states would carry the master station.  Raydist would then record the liner’s speed as it steamed directly toward or way from the buoy.  The tests proved to be successful and resulted in the Raydist being approved for use on the S.S. United States.  This success lead to many other shipyard opportunities for Hastings.  Within a few years, Raydist dominated the sea trial business in the United States.

S_S_United States

Raydist was also gaining momentum in the Hydrography and oil prospecting industry due to positive publicity from the Norfolk Corps of Engineers.  This publicity resulted in the first foreign Raydist sale in early 1951 to be used in charting the waters off Mozambique in southeast Africa.

 

During this time, Hastings completed a Raydist system for the All-Weather Flying Division of the Air Force.  It was to be used at Wright-Patterson Air Force Base in Dayton Ohio to test the accuracy of radar and other blind landing systems. Later that year, an automatic plotting board was developed to supplement the Raydist system.  The demonstration of this new product was a big event.  The board plotted a plane’s path as it performed skywriting maneuvers spelling HICO across the sky.

 

Manufacturers Rep Sales Mobile 1953A small percentage of Hastings business during the early 1950’s was for instrument sales.  The most important of these products were the air-meters, vacuum gauges, flow meters, accelerometers and an electronic standard cell. In order to grow this part of the business, Hastings decided to set up a manufacturer’s representative program.  By the end of 1953, Hasting’s was looking forward to seeing this manufacturer’s representative program vastly increasing instrument sales.

(Image on right is the first Manufacturer Representative's car outfitted with Hastings products.)

For more information on Teledyne Hastings be sure to visit our website www.teledyne-hi.com or contact us

Contact Us

Information for this blog was derived from “The Story of Hastings-Raydist” book by Carol Hastings Sanders 1979

Tags: Teledyne Hastings Instruments

Laying a Foundation (1947-1950)

Posted by The Teledyne Hastings Team on Fri, May 10, 2019 @ 01:22 PM

Product portfolio 1947-1By 1947, the Hastings Instrument Company could count many successful projects.  Their list of products included the following:

  • Raydist Navigation System
  • Magnetic Switch and Coil
  • Maximum Recording Accelerometer
  • Visibility Meter

While the list of projects was impressive, the company wanted to grow their profits further. Charles Hastings decided to look at his business model and make some changes.  The company needed to raise capital for further development in order to become a sizeable company. Growth would give the company the ability to attract and close larger contracts.  To do this, Hastings decided to incorporate the business and offer 3500 shares of stock.  The company charter was received from the Commonwealth of Virginia on Valentine’s Day 1947. 

 

Air-Meter hand lettered dial faceAfter several sales pitches and demonstrations, Hastings received two large contracts for Raydist. Along with these two contracts, the company was busy building Air-Meters for commercial sales.  Before selling the Air-Meters, the instruments needed to be calibrated.  In those early days, calibration was done by driving down the road holding a probe out the window while someone in the passenger seat held the Air-Meter.  When the car reached 5, 10, 15 etc… mph the passenger would make a note on the blank dial face and then return to the house where they would neatly letter the dial face.

 

first office brick distributorDuring this period of growth, Hastings realized that it was time to find a new location for the business.  By now, there were 17 people working elbow-to-elbow at the Hastings’ home and that could not continue.  The company settled on temporary location in an old brick distributorship building that had a leaky roof and flooded at spring tides, but it was at the price they could afford.

By the spring of 1948, several Raydist contracts were in the works. Air-Meters continued to sell very well, and several instruments were about to be introduced.  That same year, the Hastings Company also moved into a more permanent building for its now 75 employees, which would grow to 118 by 1950.  To secure the company and continue to make profits, Hastings realized he needed to produce a Raydist for commercial use.  The company achieved this goal in 1950 with a sale to the Norfolk Corps of Engineers for hydrographic surveys and channel dredging.2nd building Horne Brothers

By 1950, the line of Hastings Instruments increased to the following:

  • Air-Meter
  • Precision Air-Meter (for higher ranges and more accurate readings)
  • Maximum Indicating Accelerometer
  • Voltage-regulated Power Supply
  • Electronic Standard Cell
  • Vacuum Gauge

1950 product portfolioIVentimetern addition to the list of commercial instruments above, Hastings developed specialized instruments for specific customers. For example: the “Ventimeter” was used by the army to measure ventilation in clothing to keep wearers comfortable under extreme weather conditions.  The Hastings Company was now growing fast and generating handsome profits for its stakeholders.

 

For more information on Teledyne Hastings be sure to visit our website www.teledyne-hi.com or contact us

Contact Us

Information for this blog was derived from “The Story of Hastings-Raydist” book by Carol Hastings Sanders 1979

Register to win The History of Hastings-Raydist Book.

Tags: Teledyne Hastings Instruments

The Birth of Hastings Instruments Company (HICO) 1944-1946 (Part 2)

Posted by The Teledyne Hastings Team on Wed, Mar 13, 2019 @ 10:22 AM

Charles_Mary Hastings Home-1In September 1944, the Hastings Instrument Company started to take shape.  For quite some time, Charles & Mary conducted the business out of their home.  They received their first order in December from the Naval Aircraft Factory in Philadelphia for $800.  The order was for a rotary magnetic switch for commutating electrical circuits. 

The following month, Charles built his first heated thermopile anemometer, which he called the Air-Meter.  This Air-Meter was based on ideas he had had in 1940 for making a thermopile instrument to measure aircraft speed.  It also incorporated his invention of a way to make a thermopile compensated for both temperature and rate of change of temperature. He decided to name his radio ground speed system by combining the first syllables of the words “radio” and “distance” to form “Raydist”.

working out of homeBusiness continued to grow.  Seventeen employees would arrive at the Hastings home around 7pm on Monday, Wednesday and Friday to work on their electronic projects (see image on right).  During the day, Mary would take care of miscellaneous projects.  On one occasion, Mary agreed to have some Raydist cabinets painted by the time Charles came home.  Unfortunately, the air compressor was out of air so Mary came up with another plan.  She would take the car to the nearby service station and put as much air in the tires as she could without them bursting.  She would then drive back home, attach her paint sprayer to the tires, and paint the Raydist cabinets antennas on homeuntil her tires were almost flat.  She did this several times to complete the project before Charles came home.  The business activities took a toll on the Hastings home. The roof leaked and needed to be replaced from all the antennas mounted to it (see image on left), the driveway needed to be replaced from the damage of delivery trucks, Mary’s oven smelled like paint which caused some challenges when meal time came.

Raydist AM transmitter on helicopterIn January 1946, Hastings received their first order for a Raydist.  The Air Material Command at Wright Field in Cleveland Ohio wanted a single-dimensional Raydist system to use during aerial photography and mapping.  The final product was hand-delivered by Charles himself in October. (see image on right and below)

This Raydist order was the largest order Hastings had ever received and he felt that once they were paid for it all, their troubles would be over. 

Raydist on helicopter at Wright Airforce Base

For more information on Teledyne Hastings be sure to visit our website www.teledyne-hi.com or contact us

Contact Us

Contact Us

Information for this blog was derived from “The Story of Hastings-Raydist” book by Carol Hastings Sanders 1979

Tags: Teledyne Hastings Instruments

Before Hastings Instruments Company, the early years… (Part 1)

Posted by The Teledyne Hastings Team on Wed, Feb 13, 2019 @ 11:46 AM

charles-mary Hastings at work at NACAEver wonder where the idea or dream of Hastings originated?  Well as part 1 of our anniversary year blog posts, we thought this would be a good place to start.  Charles Hastings at the age of 10 was bitten by the radio bug and began to build and experiment with radio gear.  In 1930, at the age of 16, Charles Hastings found an opportunity to fund his experiments by fixing other people’s radios.  Many families had radios at this point, but they were very unreliable and frequently needed minor repairs.  Charles would fix radios to earn money to buy parts for his own experiments.

Soon, Charles moved on to building transmitters and enlisted the help of his high school friend, Raymond Doyle.  Their first success was when Charles spoke into a microphone and Ray heard the broadcast from his aunt’s house which was down the street. Unfortunately, the broadcast covered the entire spectrum of commercial radio broadcasting, so the entire neighborhood received the broadcast as well instead of their favorite radio programs.

After this first broadcast mishap, Hastings decided to go back to radio repair.

Charles Hastings went on to attend John Hopkins University and majored in Electrical Engineering.  Upon graduation, he was offered a position as Junior Scientific Aide with the National Advisory Committee for Aeronautics (NACA) in Hampton, Virginia. In 1939, Mary Comstock joined NACA as a mathematician and Charles was quick to ask her out for a date.  They were married within a year.

Working at NACA proved to be quite rewarding to Charles.  He came up with an idea for a magnetically operated reed switch for the spin tunnel section in order to flip the controls in its free-spinning airplane models.  This moved on to finding accurate methods to measure the speed of aircraft.  In 1940, Charles did just that, he came up with an idea for an airspeed indicator using a heated thermopile.  The idea was tested later that year at Langley Field in measuring the speed of planes.  This was the first continuous-wave heterodyne system ever used for speed measurement and was names the NACA Radio Ground Speed System.

His work continued at the NACA for a few years, but Hastings became restless and wanted to be on his own.  He felt that the work he had done with Radio Ground Speed System had more potential in the measurement of distances.  Initially Charles Hastings only wanted to create ideas for commercial products and sell the rights to others in exchange for royalties.  Hastings longtime friend James Benson was interested in being a part of this new.

Hastings Instruments Company was born in September 1944.

For more information on Teledyne Hastings be sure to visit our website www.teledyne-hi.com or contact us

Contact Us

Information for this blog was derived from “The Story of Hastings-Raydist” book by Carol Hastings Sanders 1979

Tags: Teledyne Hastings Instruments

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

Vacuum Pressure Measurement & Unit Guide

Posted by Doug Baker on Mon, Sep 22, 2014 @ 04:23 PM

Note: The content of this blog was updated February 4, 2023 to provide more information for the reader.

The applications engineers here at Teledyne Hastings discussed topics for our blog. We all agreed that one of the more frequent questions fielded, involves the units used to measure vacuum levels. We find that the technicians who use their vacuum system daily often seem to develop a sixth sense about the “health” of their systems. They know something isn’t quite right when the base vacuum pressure (or rate of pressure change) is not what they expect. So, when vacuum pressure measurements are inconsistent from batch-to-batch, that is the time when the user stops to ask the meaning behind the data that their vacuum measurement instrumentation is providing.

Measuring Vacuum Pressures

A vacuum exists when there is negative pressure, or when there is system pressure that is less than atmospheric pressure. Manufacturing processes generate different levels of vacuum when operating at peak efficiency for a given vacuum application that are measured using a vacuum gauge. Absolute vacuum is the absence of all matter. Atmospheric pressure, also known as barometric pressure, is the pressure due to earth’s atmosphere. Atmospheric pressure is 760 Torr or 14.696 psia at sea level and changes with altitude. The vacuum pressure scale is book-ended by absolute vacuum pressure in the “ultra-high” vacuum range and atmospheric pressure at the “rough” vacuum range. It should be noted that absolute vacuum, or perfect vacuum, is never truly attained.

Most users know that vacuum is commonly measured using units of pressure. There are a few different systems of pressure measurement, and this blog will discuss those most used. In Armand Berman’s book, Total Pressure Measurements in Vacuum Technology, pressure unit systems are divided into two categories: “Coherent Systems” and “Other Systems”.

Common Units of Vacuum

“Coherent Systems” of units are based on the definition of pressure (P) as the force (F) exerted on a chamber wall per unit area (A). P = F/A. The International System of Units, or SI units, is commonly used for pressure measurement. http://physics.nist.gov/cuu/Units/units.html The SI unit for pressure is the Pascal (Pa), and it is interesting to note that NIST (National Institute of Standards and Technology) published papers are always required to use SI units. Again, the SI unit for pressure (force per unit area) is the Pascal. 1 Pa = 1 N /m2.

As a unit of pressure, the Pascal is not always convenient to use because vacuum systems often operate in pressure ranges where collected data results in large numbers. For example, near atmospheric pressure, we would measure approximately 100,000 Pa. So, a more convenient unit, the bar, was developed. (1 bar = 100,000 Pa)

Moving lower in pressure, it is very helpful to then use the mbar (1 mbar = 0.001 bar), which has become the predominate unit of measure in Europe, as the basis for describing pressure levels. As a specific example, look at the base pressure specification of a turbo pump, which will typically be given in terms of mbar (e.g., Base Pressure < 1 x 10-10 mbar).

“Other Systems” of units include the Torricelli system, which is based on an experiment (shown in the diagram below) conducted by the Italian scientist, Evangelista Torricelli. In this experiment, the pressure exerted on the mercury can be shown to be P = hdg, where h is the height of the mercury column, d is the density, and g is the acceleration due to gravity.

Simple Barometer

By measuring the mercury column height, the pressure can be determined. The Torr unit (named after Torricelli) has been defined as 1 millimeter of mercury (1 Torr = 1 mmHg). This unit, as well as the use of the mTorr unit (1 mTorr = 0.001 Torr), is commonly used in the United States. Historically, pressure was sometimes described in terms of “microns”, which simply meant a mercury column height of one micron (1x10-6 m). Note that the micron and the mTorr are the same.

Lastly, it should be noted that occasional confusion arises between the use of different, but seemingly similar, units of pressure. As explained above, the mbar and the mTorr are not the same. One mbar has the same order of magnitude as one Torr (1 mbar = 0.75 Torr).

 

Unit Conversions

The table below gives some conversion values between various commonly used units of pressure and vacuum. A useful website for conversions:

http://www.onlineconversion.com/pressure.htm

 

Pa

mbar

Torr

mTorr (micron)

Atm

1 Pa =

1

0.01

0.0075

7.50

~ 10-5

1 mbar =

100

1

-.75

750.06

~ 10-3

1 Torr =

133.3

1.333

1

1000.0

~ 10-3

1 mTorr (micron) =

0.1333

0.00133

0.001

1

~ 10-6

1 Atm =

101,325

1013.25

760

760,000

1

 

Absolute Pressure and Gauge Pressure

In conclusion, keep in mind that vacuum measurements can be referenced to ambient pressure, gauge pressure measurement or absolute pressure measurement (perfect vacuum). An absolute pressure measurement is referenced with respect to absolute vacuum. Absolute pressure will often be designated by the letter “a” after the unit of measure; “psia.” ​As an example, an absolute pressure reading of 30 psia (pounds per square inch absolute) is a pressure that is 30 psi above vacuum. It is important to understand that there is no negative absolute pressure. There are some

Gauge pressure measurements are measured relative to the ambient atmospheric pressure. Relative, or gauge pressure, will often be designated by the letter “g” after the unit of measure; “psig.” As an example, 30 psig is a gauge pressure that is 30 psi above ambient atmosphere (typically 14.7 psia at sea level). In this example the gauge pressure, 30 psig, is equal to an absolute pressure of 44.7 psia.

 

What is a vacuum system?

A vacuum system can consist of multiple a vacuum pumps and vacuum gauges attached to a tank that is designed to measure below atmospheric pressure. The vacuum pumps reduce the air pressure inside of the tank to the pressure range that the vacuum pump is rated for. Different vacuum pumps bring the vacuum pressure to different levels depending on the strength of the vacuum pump.

Attached to the tank is usually at least one vacuum pressure gauge. An application may require another type of vacuum gauge to measure a different pressure point. An example of this would be using a piezo pressure gauge and a Pirani pressure gauge to have a larger range of the vacuum pressure measured. A piezo vacuum gauge would be used to measure the rough vacuum range around atmosphere and the Pirani could be used to measure below 1 Torr in the mTorr range. There are vacuum gauges that use technologies from different vacuum gauges to create a combination vacuum gauge to measure vacuum pressure across a wider pressure range. Teledyne Hastings combines both the Pirani and piezo technologies to make the HVG-2020B vacuum pressure gauge.

 

Vacuum Gauges Poster

Mass Flow - Vacuum Gauge Posters

Vacuum Gauges
Free Poster
Unit Conversions and More

Please send me the poster(s)

 


Original Content posted Sept 22, 2014

FAQ Corner - Units for Vacuum Measurement
an overview of units used to measure pressure

Earlier this year, the applications engineers here at Teledyne Hastings discussed topics for our blog. We all agreed that one of the more frequent questions that we discuss with folks involve the units used to measure vacuum levels. We find the technicians who use their vacuum systems daily often seem to develop a sixth sense about the “health” of their systems. They know something isn’t quite right when the base pressure (or rate of pressure change) is not what they expect. So, when pressure measurements are not consistent from batch to batch, that is the time when the user stops to ask the meaning behind the data that their vacuum measurement instrumentation is providing.

Now, most users know that vacuum is commonly measured using units of pressure. There are a few different sets of pressure units, and this blog will discuss the more commonly used ones. In Armand Berman’s book, Total Pressure Measurements in Vacuum Technology, pressure unit systems are divided into two categories: “Coherent Systems” and “Other Systems”.

Coherent Systems of Units are based on the definition of pressure (P) as the force (F) exerted on a chamber wall per unit area (A). P = F/A.  The International System of Units, or SI units, is commonly used for pressure measurement. http://physics.nist.gov/cuu/Units/units.html  The SI unit for pressure is the Pascal (Pa). It interesting to note that at NIST (National Institute of Standards and Technology), published papers are always required to use the SI set of units. Again, the SI unit for pressure (force per unit area) is the Pascal. 1 Pa = 1 N /m2.

Now, the Pascal as a unit of pressure is not always the most convenient because vacuum systems are often operating in a range of pressures where we would need to collect data using large numbers. For example, near atmospheric pressure, we would measure approximately 100,000 Pa. So, a more convenient unit, the bar, has been derived. (1 bar = 100,000 Pa)

Moving lower in pressure, it is very helpful to then use the mbar (1 mbar = 0.001 bar). So many vacuum users, especially in Europe, use the mbar as the basis for describing pressure levels. As a specific example, look at the base pressure specification of a turbo pump, it will be given in terms of mbar (e.g. Base Pressure < 1 x 10-10 mbar).

Another system of pressure units is based on the Torricelli experiment (shown in the diagram). In this experiment, the pressure exerted on the mercury can be shown to be P = hdg, where h is the height of the mercury column, d is the density, and g is the acceleration due to gravity.

Simple Barometer

By measuring the mercury column height, the user can determine the pressure. The Torr unit (named for the Italian scientist Torricelli) has been defined to be 1 millimeter of mercury (1 Torr = 1 mmHg). This unit is very common, especially in the United States. It is also common to use the mTorr (1 mTorr = 0.001 Torr). Many years ago, pressure was sometimes described in terms of “microns”, which simply meant a mercury column height of one micron (1x10-6 m). Note that the micron and the mTorr are the same.

One last word about the units used to measure vacuum: on occasion, there is confusion between pressure units. As we have seen above, the mbar and the mTorr are not the same. One mbar has the same order of magnitude as one Torr  (1 mbar ≈ 0.75 Torr).  The table below gives some approximate conversion values. A useful website for conversions:

 http://www.onlineconversion.com/pressure.htm

 

Pa

mbar

Torr

mTorr (micron)

Atm

1 Pa =

1

0.01

0.0075

7.50

~ 10-5

1 mbar =

100

1

0.75

750.06

~ 10-3

1 Torr =

133.3

1.333

1

1000.0

~ 10-3

1 mTorr (micron) =

0.1333

0.00133

0.001

1

~ 10-6

1 Atm =

101,325

1013.25

760

760,000

1

Douglas Baker is the Director of Sales & Business Development of Teledyne Hastings. Antonio Araiza prepared the Torricelli experiment drawing. Antonio is the head of Technical Documentation at Teledyne Hastings (and is among the best soccer referees in the Commonwealth of Virginia).

Tags: Teledyne Hastings Instruments, pressure, mTorr, mBar, micron, pascal, torr, vacuum pressure, units of measurement, vacuum gauges, vacuum meters, vacuum controllers

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, Flow Meter, mass flow conversion, Mass Flow Calculator, Mass Flow Range, Gas Flow Range, Mass Flow, 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, Gas Flow Range, pressure, range, differential pressure, mass flow controller, mass flow meter

FAQ Corner – Teledyne Hastings Instruments at Pittcon 2013

Posted by Brandon Hafer on Wed, Mar 13, 2013 @ 03:20 PM

It’s hard to believe that it is now March, which means that Pittcon 2013 is right around the corner. Teledyne Hastings Instruments will have Applications Engineers and representatives in attendance to answer all of your mass flow and vacuum instrumentation questions.

 

PITTCON 2013 LOGOPittcon is an annual conference on laboratory science that is organized by The Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. Pittcon started as a small technical conference held in 1950. The first 18 conferences were held in Pittsburgh, Pennsylvania, but the conference has since grown. Locations now vary from year to year with this year’s conference being held at the Pennsylvania Convention Center in Philadelphia, Pennsylvania from March 17-21.

 

There have been many changes over the 60 plus years of the Pittsburgh Conference, and remains a worthwhile event to attend. Teledyne has had a presence at the event for the past 35 years. Included in the weeks events are thousands of exhibitors, numerous technical programs and lectures, and short courses. It provides the opportunity to meet and interact with scientist from across the country and around the world. Papers and articles are presented daily, illustrating the advancements in science in the past year. And finally, it allows for a single location to walk around and see over 17,000 companies and exhibitors with their products and technologies.

Teledyne Technologies Incorporated will have 4 companies in attendance at Pittcon this year. In addition to Teledyne Hastings Instruments, Teledyne Tekmar, Teledyne Leeman Labs, and Teledyne Judson will be exhibiting. Teledyne Tekmar is a leader in the design and manufacturing of analytical instrumentation including products for gas chromatography sample introduction, total organic carbon (TOC) and total nitrogen (TN) analyzers. Teledyne Leeman Labs is a producer of world-class instruments for elemental analysis including ICP spectrometers, atomic absorption spectrometers and mercury analyzers. Teledyne Judson is a leading designer and manufacturer of high performance infrared detectors and accessory products. The Teledyne family of companies will be located in booths 916 and 917, which are located near Entrance D to the Pennsylvania Convention Center. Teledyne employees will be giving presentations on a variety of topics while at Pittcon. If you would like more information on the schedule or the topics to be covered please contact us or stop by our booth and we can provide that information.

Teledyne Hastings Instruments has a great deal of experience with the analytical instrumentation industry. We are always interested in new applications even if they do not exactly fit into the standard product design for mass flow or vacuum instrumentation. We are very willing to examine possible custom designs to meet the requirements of your system. Some examples of previous custom applications include a variety of non-standard packages for both our mass flow and vacuum products, modified electronics, high pressure designs, and even custom designed flow and vacuum sensors.

 

We welcome your comments and your questions and look forward to seeing you at Pittcon 2013. Please stop by our booth and discuss your projects with either Vikki Jewel or Brandon Hafer. You can also email your questions to Victoria.Jewell@Teledyne.com or Brandon.Hafer@Teledyne.comand we’ll be happy to respond and work with you. 

Brandon Hafer is an Application Engineer with Teledyne Hastings Instruments. He was raised in Pottsville in Eastern Pennsylvania and is a fan of the Philadelphia Phillies and Philadelphia Eagles. He is looking forward to returning to the Philadelphia area for Pittcon 2013. If you would like to contact him, he can be reached at brandon.hafer@teledyne.com.

 

 

 

Tags: Teledyne Hastings Instruments, vacuum instruments, mass flow instruments