Teledyne Hastings Instruments Blog

Teledyne Hastings is working to expand our throughput so that we can better serve our customers by meeting increased demand while decreasing lead times. Over the last several months, we have added and improved calibration systems in both our vacuum and flow production areas. We have also purchased a new vacuum furnace which increases our production capacity. In this blog, we will describe what a vacuum furnace is, how it functions, and how we use it.

A picture of our newest vacuum furnace is shown below.  The three major components of the vacuum furnace, from left to right, are the high-speed diffusion pump, the vacuum chamber with a high temperature hot zone, and the control cabinet. The diffusion pump is capable of pumping 180,000 lpm.  While the pumping speed may seem unnecessarily high for the given volume, keep in mind that the gas load, at high temperature, can be very high. The diffusion pump is connected to the hot zone chamber via a large right angle vacuum valve. The diffusion pump is backed by a rotary vane vacuum pump. Pressures in the foreline can be monitored by using a Teledyne DV-6R vacuum gauge tube. The base pressure of the system, with the heat zone at room temperature approaches 1 x 10^-6 Torr.

 Leon Whitehead at the controls of the new vacuum furnace.

The hot zone is the heart of the vacuum furnace. A picture showing the inside of the hot zone is shown below. The effective hot zone size is 12”w x 12” h x 24” d. The molybdenum rod elements inside the hot zone are resistively heated once the system has reached sufficient vacuum. Under vacuum, the hot zone can reach temperatures exceeding 1300°C (2372°F).

Inside the hot zone. Note the series of Molybdenum rod elements.

The vacuum furnace is controlled by a touchscreen panel with PLC. The operator can select and execute a pre-programmed temperature/time profile for a given task. In addition, pressure and temperature at various locations on the system are monitored and displayed. The control cabinet also includes the transformers, contactors, and fuses. 

Teledyne uses our vacuum furnaces for both fusing and brazing operations - all while precisely controlling the environmental conditions within the hot zone. In a typical schedule, the system is pumped out to its base pressure and then the hot zone is brought up to 800°C. After reaching this temperature, the hot zone is held for a period of 20 minutes. Next, the hot zone is slowly ramped to 1100°C, which takes about an hour. The hot zone is then held there for up to 1 ½ hours.

Teledyne Hastings Instruments is an ISO 9001:2008 certified manufacturer and we produce a complete line of instruments for precise measurement and control of vacuum, pressure, and gas flow. Our vacuum furnaces and the corresponding Quality Work Instructions deliver consistent results, which in turn provide our customers with high quality instrumentation. For information on Teledyne Hastings and our Mass Flow Meters and Controllers or Vacuum Gauges, please visit www.teledyne-hi.com or click the button below.

Teledyne Hastings designs and build mass flow controllers for a broad array of markets from clean laboratory environments to heavy industrial installations. Recently, we have been asked to provide our newest line of Digital 300 Flow Meters and Controllers into more demanding environments. And, we are proud to offer an optional IP-67 enclosure, which provides protection against dust and water. More on our product later in the blog.

But first, let’s explore the IP, or Ingress Protection, rating system.  NEMA (National Electrical Manufacturers Association) publishes a standard (ANSI/IEC 60529-2004) entitled, “Degrees of Protection Provided by Enclosures (IP Code)”. The corresponding international standard is IEC 60529. The introduction to the IP Code starts:

This standard describes a system for classifying the degrees of protection provided by enclosures of electrical equipment for two conditions: 1) the protection of persons against access to hazardous parts and protection of equipment against the ingress of solid foreign objects and 2) the ingress of water.

The IP Code rates the degree of protection by using two numbers. The first number describes protection against solid particles; the second number describes protection against liquids. The Wikipedia page describing the IP Code provides a couple of nice tables to help us quickly understand the numbers.

Which now brings us back to the Teledyne IP-67 rated enclosure. The first number, “6”, indicates that our enclosure is completely protected against dust. The second number, “7”, indicates that our instrument can withstand submersion in water up to a meter in depth for up to 30 minutes.

One side note about IP ratings, if you follow the battle between Samsung Galaxy and Apple iPhone, you may have seen an article published by CNET last September (2017). In the article, it was stated that the iPhone 8 and 8 Plus are certified with an IP67 rating, while the Samsung Galaxy S8 is rated IP68. And by the way, yes… according to Reddit, the whole putting the wet iPhone in rice thing to dry it out, does work.  

In order to claim the IP-67 rating, Teledyne Hastings has sent test instruments to NCEE Labs in Lincoln Nebraska. In general, there are two tests, one for dust and one for water. Aaron Steggs, Senior Test Engineer with NCEE explains, “The testing to receive the dust rating is not trivial. There is a vacuum test on the enclosure to ensure that no ingress of dust can occur. The vacuum pressure used is 2kPa.”

Aaron goes on to explain a little about the water test, “When talking about immersion testing, there is a greater chance of water being forced into any opening due to the weight of the water about the instrument under test.”

In any case, we have passed both the dust and water test and now you can have the accuracy and fast response of the Digital 300 Series in an IP rated enclosure.

For more info about our digital 200 mass flow meters and controllers, please visit www.teledyne-hi.com or click the button below for more inforamation on the IP-67 version now available.

February is the month when citizens in the United States celebrate the history and culture of African-Americans. In early Feburary, scientists from the Pressure & Vacuum Group at NIST (National Institute of Standards & Technology) installed a special case designed to hold President Abraham Lincoln’s first handwritten draft of the Emancipation Proclamation and 13^th Amendment in the Smithsonian’s National Museum of African American History & Culture. You can watch a video of the installation here:

https://www.nist.gov/video/nist-behind-scenes-installation-emancipation-proclamation

The Emancipation Proclamation freed slaves in the Confederate States in 1863. After the Proclamation, the American Civil War becomes more about the struggle for freedom. In turn, Emancipation becomes law for the entire United States via the 13^th Amendment to the US Constitution.

The priceless handwritten draft is now stored in in a sealed case with monitoring instrumentation. According to an article posted on the NIST website (https://www.nist.gov/news-events/news/2017/04/making-airtight-case-freedom ), the system tracks pressure, temperature, relative humidity, and oxygen content. The NIST article also says that the system uses 4% oxygen to help maintain the color of the iron gall ink.

Now, another interesting thing we can celebrate about the Emancipation Proclamation is the famous Emancipation Oak. Located on the campus of Hampton University, in Hampton Virginia. Note that Hampton is also the home of Teledyne Hastings. The Emancipation Oak was the site of the first reading of the Proclamation in the South according to the Hampton University Website (http://www.hamptonu.edu/about/emancipation_oak.cfm ). The tree has a diameter of over 100 feet and the oak has been designated as one of the 10 Great Trees of the World by the National Geographic Society.

For information on Teledyne Hastings and our Mass Flow Meters and Controllers or Vacuum Gauges, please visit www.teledyne-hi.com or click the button below

We held a webinar on thermal mass flow meter / controller calibration best practices.  Topics included:

• Equipment
• Techniques and Tips
• Record Keeping / Documentation

If you are interested in calibrating in-house or using a third party then be sure to watch this webinar presented by Teledyne Hastings Instruments and guest speaker Jaime Shanahan of Chell Instruments, Ltd.  

Teledyne Hastings Instruments has been providing accurate, reliable, repeatable flow and vacuum instruments across a variety of industrial and academic applications for decades. Today, we have a fully staffed repair and calibration department in Hampton, VA and Factory Certified Service Centers in Northern California, UK, South Korea and China.  

5 Reasons for Periodic Recalibration:

• Aging / Stress
• Contamination
• Tolerance Shifts
• Consistent Quality of the End Product
• Reduced Process Inefficiencies

As we say good-bye to John Glenn, it is a good time for Teledyne Hastings to recall with pride our company’s and our city’s connection to this great American hero. Now, many people know that John Glenn was the first American to orbit the earth. But most people don’t know that the original seven Mercury astronauts, including John Glenn, received their original spaceflight training in 1959 at NASA-Langley in Hampton Virginia which is also our home for Teledyne Hastings.

The Hampton Roads area of Virginia has memorialized several landmarks to commemorate Project Mercury. There are several bridges in the city of Hampton which are named for the astronauts. “Military Highway” was renamed to Mercury Boulevard. And, in Newport News, the Denbigh branch of the Newport News Public Library System is the “Grissom Library”.   

NASA was formed in late 1958 when NACA operations were converted over. Previously, NACA (National Advisory Committee for Aeronautics) was established in 1915 and built Langley field in Hampton. Now in doing some background reading for this blog, I found it interesting to learn that NACA was created out of fear that the U.S.A. might be falling behind the Europeans in aeronautics and that NASA, in turn, was created out of fear that the U.S.A. was falling behind the Soviets in the Space Race.

In a book entitled The Story of Hastings-Raydist, Carol Saunders points out that NACA did not hire many engineers during the first part of the Great Depression. But, in 1935, NACA accelerated hiring and they brought on Charles Hastings as a “Junior Scientific Aide”. In 1939, a newly hired mathematician named Mary Comstock was hired and placed in an office across the hall. The two were married and together created Hastings Instruments in 1944.

And speaking of mathematicians at Langley, there is a movie “Hidden Figures” (released December 25, 2016), which tells the story of three female mathematicians who were part of the computer pool. Which brings us back to John Glenn. In the early days of computers, engineers did not always trust the results of the electronic data processors. The computer pool, in other words, human mathematicians, were used to crunch through complex calculations. Before his historic flight in 1962, Glenn requested that one of these computer pool women, Katherine Johnson, verify the results of the computer. The contributions of these women to the space program was remarkable.

For more information on Teledyne Hastings Instruments click the button below or visit www.teledynehastings.com

The following books were referenced in the writing of this blog:

Hidden Figures by Margot Lee Shetterly

Hampton - From the Sea to the Stars edited by James T. Stensvaag

The Story of Hastings-Raydist by Carol Hastings Saunders  

Teledyne Hastings is proud to release our newest, most advanced, line of digital flow meters and flow controllers - the 300 Vue. In this blog, we will discuss the three types of Input/Output (I/O) that can be used with the 300 Vue. These are: Analog, Digital, and Touchscreen Display.

(1)   Analog

The 300 Vue is very flexible. The instrument can be configured to give and receive analog signals. For example, the 300 Vue can use 0-5 VDC, 0-10 VDC, 4-20 mA, or 0-20 mA.

Let’s take a look at a 300 Vue flow controller which has been setup to have a full scale flow rate of 100 sccm and has 0-5 VDC I/O. In the case of a flow controller, there are two analog voltage signals that we need to understand. The first is the flow output signal. In our example (0-5 VDC), 5 VDC corresponds to 100% of the full scale of the flow controller. The relationship between the voltage output signal and flow rate is linear. So, if we have an output of 1 VDC from the 300 Vue, then we would have a flow rate of 20% of full scale which corresponds to 20 sccm (20% * 100 sccm = 20 sccm).

Correspondingly, in our example, the 300 Vue will accept an analog command signal between 0 and 5 VDC. Again, 5VDC corresponds to 100% command signal. The command signal tells the flow controller how to set the flow rate. So, if we wanted the flow rate to be 75 sccm, we would provide a 3.75 VDC command voltage  (75 sccm* (5 VDC/100 SCCM) = 3.75 VDC).

One last comment before we move on. Analog I/O is still used in many applications. Older flow power supplies and PLC’s often utilize analog I/O. The 300 Vue flow instrument makes it easy to integrate into these systems.

Interested in more information on the Vue? click here

(2)      Digital

The 300 Vue can provide digital I/O via RS232 or RS485. Connection to the digital port is made via the micro USB connector or the small bayonet-style connector. Let’s take a quick look at an RS232 command for the 300 Vue. If we send “F”, the 300 Vue will respond with the flow rate.

f <cr> <lf>

25.889 sccm

Simple - right? Now in the case of a flow controller, we will want to be able to send a command signal to tell the flow controller how to set the flow rate. One way to do this is to use V5, the “Setpoint”. The Setpoint Command is simply the flow rate expressed as a percent of the flow controller’s full scale. So, “V5=100” will set the flow rate to 100% of full scale. You can also use V4 which sends the command in the given units, as opposed to % of full scale.

Digital communication with the 300 Vue can be utilized in a few different ways. First, you can use our free user software which can be obtained from our website. If you want to see all of the capability (including flow data logging) you can watch this short “How To” video.

Next, many of our digital flow controller users write their own code using LabView. By working with the “F” and the “V5=  “, or “V4=  “ commands, the user can easily read and control the flow rate in their application.

Here at Teledyne, we often use TeraTerm for communicating with our digital flow instruments. Click to visit TeraTerm website for more information.   

TeraTerm is nice because it is open source (free) yet it is very powerful. I also like the fact that TeraTerm allows the user to save and restore a communication set up file. In other words, once you have a TeraTerm “ini” file working, you can save it so that you don’t have to reconfigure the settings each time you start up the program. If you have TeraTerm and would like a copy of my setup file for the 300 Vue, just send me an email. 

Interested in more information on the Vue? click here

(3)      Touchscreen Display

Ok, we’ve talked a little bit about analog I/O and digital communications. Now, let’s explore the coolest feature of the 300 Vue – the color touchscreen display. With the touchscreen display, it is very easy to see and control the flow rate. First, we should point out that the 300 Vue flow instrument is very easy to power up; you just plug in the connector and you are in control.

Once the flow instrument is powered, the flow rate is observed as shown in the picture below:

Now, to change the flow setpoint or command signal we touch Setpoint and we see the numeric keypad screen as shown below.

Changing the setpoint is easy… you just type the value you want and hit ENTER. The display then returns to showing the flow rate.

The 300 Vue is very flexible with respect to Inputs and Outputs. If you have questions about I/O, our applications engineers are always standing by and ready to help. You can reach us at hastings_instruments@teledyne.com or by calling 1-800-950-2468.

There 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.

Each 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.

The 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

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

One of the goals of these blog postings is to give readers knowledge about vacuum and mass flow technology. The Society of Vacuum Coaters has established a foundation (SVCF) with a similar goal. Dr. Don McClure (Acuity Consulting & Training) has created “The Vacuum Wizard Video”. Dr. McClure worked at both IBM & 3M and has been teaching for over 20 years about vacuum coating onto flexible substrates.

As stated on the SVCF website, “The Vacuum Wizard Video brings to life the fundamentals of vacuum and vacuum coating technology through an informal and thought provoking presentation using non-technical jargon and filled with live demonstrations.

The Vacuum Wizard Video seeks to raise awareness of students and educators about the fascinating world of vacuum and vacuum coating technology. The only prerequisite is a curiosity about this amazing technology.

The Vacuum Wizard Video can be a useful training tool in the corporate world for personnel who require a basic understanding of vacuum technology. Sales representatives, customer service personnel, field service and maintenance technicians, lab technicians, and engineers with no vacuum technology background, can all benefit from the Vacuum Wizard Video.”

(Check out the Teledyne Hastings’ Vacuum Model 2002 Vacuum Gauge on the table)  Click the button below to request an evaluation sample of the 2002 Vacuum Gauge

You can get more information about the SVC Foundation and the video series by visiting:

http://svcfoundation.org

Click to see a sample of the Vacuum Wizard Video 

We are occasionally asked for the turndown ratios of our flow meters and flow controllers.  There are varying perceptions as to what this term actually means.

The turndown ratio of a Mass Flow Meter (MFM) or Mass Flow Controller (MFC) defines the usable range for which it can operate while maintaining its published accuracy.  It can be expressed using the following formula:

A flow meter with a large turndown ratio will have a large operating range.  This can also be indicative of the flow meter’s cost.  For example, variable area flow meters (rotameters) typically have lower turndown ratios compared to thermal mass flow meters.

Most analog mass flow meters have an accuracy of ± 1% of Full Scale (FS) and have resolution better than 1%.  The usable range is from 1% to 100%.  They will have a turndown ratio of 100/1 or more commonly expressed as 100:1.  Digital flow meters will have an even greater turndown ratio due to their higher accuracy.

Most analog mass flow controllers also have an accuracy of ± 1% FS.  However, they typically have an automatic valve shut circuit that closes the valve at flow rates below 2% of FS.  This is to ensure full valve closure in the event of a small zero offset.  The usable range is from 2% to 100%.  Since measurement is not possible below 2%, these will have a turndown ratio of 100/2 = 50/1 or 50:1.

 For more information on Turndown Ratio or our Flow Meters, please contact Wayne Lewey 

This is part two of a two-part blog on Thermal Mass Flow sensors.  In part one, we described the desired characteristics of a thermal mass flow sensor.  In part two, we will discuss the operation of the 300 series flow sensor (Patent #6,125,695) and how its design addresses the desired traits.

In our previous blog, we showed a cutaway of a thermal mass flow meter.  Now let’s take an inside look at the 300 series flow sensor:

When gas is flowing through the bypass shunt, a small pressure drop is developed which will direct a fraction of the flow through the arced / semi-circular capillary tubing in the flow sensor. On the outside of the capillary tube, there are two resistive wire coils which are tightly wound and in excellent thermal contact with the tube. These two identical windings are referred to as:

• Upstream Heater Coil (1)
• Downstream Heater Coil (2)

Associated with each of the two heated coils is an ambient coil. The ambient coil is in excellent thermal contact with the aluminum ambient block.  Aluminum has a very high thermal conductivity which ensures that both ends of the sensor tube and the two ambient coils (3 and 4) will be at the same temperature.

Two identical Wheatstone resistance bridges are formed from the two pair of coils (see image on right).

The circuit shown in the image on the right is designed to ensure that the heated coils (upstream and downstream) are maintained at a constant temperature (ΔT) above the corresponding ambient coils.

Next, we calculate the power (W) required to maintain ΔT by:

This power will be calculated for both the upstream bridge and the downstream bridge. It can be shown that:

So, by maintaining both heaters at the same ΔT above ambient, the mass flow rate is directly proportioned to the difference in power (W) between the two bridges. For example, when no flow is passing through the capillary sensor tube, the power needed to maintain ΔT will be the same (i.e. ṁ = 0)

As gas flow increases in the tube, heat is transferred from the upstream heater to the gas stream.  This will force the upstream circuit to use more power to maintain ΔT. In turn, the gas will transfer heat to the downstream heater which will cause the downstream circuit to use less power to maintain ΔT.

Now, here is the best part: the mass flow rate is directly proportional to the power difference. In other words, LINEARITY!

In our previous blog, we discussed how excellent linearity leads to improved accuracy. And, not only does the 300 series sensor give excellent linearity, the circuit shown on the right reacts very fast to changing flow. Thus, the 300 series has excellent responsive time.

One last note, we have designed the 300 series to use relatively large diameter tubing.  This larger tubing allows flow meters to be designed with lower pressure drop than many mass flow meters on the market.  

Visit our website for more information on Teledyne Hastings 300 series Flow Meters.

Teledyne Hastings' Thermal Mass Flow Sensors are used worldwide.  Download our application note on High Throughput Leak Detection to learn about improving lead testing precision and throughput and how to reduce testing time.  

Be sure to visit our website for additional information on Teledyne Hastings Mass Flow Controllers and Mass Flow Meters