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Teledyne Hastings Instruments Blog

Thermal Mass Flow Meter Calibration

Posted by The Teledyne Hastings Team on Fri, Jan 26, 2024 @ 10:00 AM

Flow ControllerCalibration is the cornerstone of measurement accuracy, ensuring that instruments deliver reliable and precise data. Thermal mass flow meters play a pivotal role in providing a dependable solution for various industries. The calibration of these instruments is a critical factor that demands meticulous attention. In this blog, we delve into the intricacies of thermal mass flow calibration, unraveling the science behind it and its significance in achieving accurate measurements.

 

The Basics: What is Thermal Mass Flow Meter Calibration?

Teledyne Hastings’s flow meters and flow controllers use thermal mass flow sensors. The Teledyne Hastings Instruments 200 Series thermal mass flow meters operate on the principle of heat transfer using thermocouple technology. The flow sensor consists of a capillary tube that is heated at the midpoint. Thermocouples are used to measure the temperature on both the inlet and outlet ends of the tube. As gas molecules travel through the flow sensor, heat is transferred downstream. The temperature differential between inlet and outlet correlates to the molecular flow rate of the gases. The molecular flow rate is directly proportional to the mass flow rate of the fluid. This relationship forms the basis for the calibration process, as accurate calibration ensures that the meter provides reliable measurements across a range of flow rates and conditions.

Calibration is indispensable for maintaining the accuracy and reliability of thermal mass flow meters. Over time, factors such as contamination, sensor degradation, environmental changes, or wear and tear can impact the meter's performance. Calibration allows for the correction of these deviations, ensuring that the meter consistently produces accurate readings. Moreover, many industries are subject to regulatory standards that mandate regular calibration to guarantee the reliability of the data collected.

 

How To Calibrate Your Mass Flow Meter

Calibration Reference
  1. The first step in thermal mass flow calibration is establishing a reference standard. This is typically a device with a known and traceable accuracy. The reference standard is used to compare and verify the accuracy of the mass flow meter being calibrated. This can be a reference standard or another flow meter. A high accuracy 300 Vue thermal mass flow meter or mass flow controller with local touchscreen display would create a standard that the unit under calibration will match to.

  2. Calibration involves subjecting the flow meter to controlled flow rates covering its entire operating range. The meter's response to these different flow conditions is carefully observed and compared to the reference standard. The best calibration would be used with actual gas to get the most accurate data points. Since the actual gas (e.g. Helium) could be expensive or rare, then a more accessible gas such as N2 or Air is used with a conversion factor to calculate the actual flow rate in the desired gas.

  3. As the flow meter undergoes calibration, data on its performance at various flow rates is collected. This data is then analyzed to identify any deviations from the reference standard. The reference temperature and pressure may differ from the actual process temperature and pressure. Calibration software may be employed to streamline this process.

    Calibration Report
  4.  If discrepancies are detected, adjustments are made to the thermal mass flow meter to correct its readings. This may involve recalibrating sensor elements or updating compensation factors. The goal is to align the meter's measurements with the reference standard. It is important to note how large these discrepancies are as it may require repair instead of calibration.

 

 

 

Tags: Thermal Mass Flow Meter

Working Principle of Thermal Mass Flow Meters

Posted by The Teledyne Hastings Team on Thu, Jan 25, 2024 @ 03:32 PM

HFC-D-302B

In the world of fluid dynamics and process control, selecting the appropriate flow measurement parameter is crucial for accurate and reliable data. Teledyne Hastings’s uses heat transfer technology to indirectly measure the molecular flow rate of dry gases. Our instruments can be used with volumetric flow units as they are converted to find the mass flow rate.

 

CONTACT US FOR MORE INFORMATION

 

What is the Thermal Mass Flow Meter Working Principle?

Basic Design:Basic Principle Flow Meter - 4 Components

A mass flow meter consists of four basic components:

  1. Electronic Circuit Board
  2. Flow Sensor
  3. Bypass Shunt
  4. Base

*See Figure on right

 

In the world of fluid dynamics and process control, selecting the appropriate flow measurement parameter is crucial for accurate and reliable data. Teledyne Hastings’s uses heat transfer technology to indirectly measure the molecular flow rate of dry gases. Our instruments can be used with volumetric flow units as they are converted to find the mass flow rate.

 

200Series Sensor Design200 Series graph

 

 

 

 

 

 

 

 

There are numerous thermal mass flow sensor designs.  The Teledyne Hastings’ 200 Series sensor is shown in image on left.  This thermal mass flow sensor consists of a small 316SS capillary tube with a heater winding located in the center.  A thermocouple (TC-1) is located on the inlet side and another thermocouple (TC-2) is located on the outlet side.  At zero flow (no gas flow), the heat is transferred through the capillary tube in both directions towards the two thermocouples, each of which has the same temperature (see image on right, ZERO FLOW condition).  As gas flow moves through the capillary tube (inlet to outlet), heat is then transferred downstream by the gas molecules.  The temperature of TC-2 will increase, while the temperature of TC-1 will decrease.  This temperature differential correlates to the molecular flow rate of the gases (mass flow). 

 

Output:

A majority of thermal mass flow meters provide an analog output signal (0-5vdc, 4-20mA, etc.) that is directly proportional to the gas flow rate.  System integrators can directly acquire this signal for process control.  

THCD-101 and THCD-401


If the installation is not configured for data acquisition, Teledyne Hastings offers convenient power supplies with integrated displays (see models THCD-101 and THCD-401 in image on right) and ready-to-use connector cables for quick start-up.

 

 

HFC-D-302B

 

 

 

Some mass flow meters offer digital communication to convey the flow rate, while other models have a built-in color touchscreen display (See model HFC-D-302B Vue in image on left).​

 

 

 

 

 

 

Thermal Mass Flow Meter Advantages

Thermal mass flow meters have gained widespread popularity in various industries due to their numerous advantages in measuring the flow of gases. Let's explore some of the key advantages of thermal mass flow meters:

 

1. Direct Mass Flow Measurement:

One of the primary advantages of thermal mass flow meters is their ability to directly measure mass flow rate. Unlike other flow measurement methods that may require additional measurements or assumptions about fluid properties, thermal mass flow meters provide a direct and accurate measurement of gas flow.

2. Insensitive to Changes in Pressure and Temperature:

Thermal mass flow meters are less affected by variations in pressure and temperature compared to some other flow measurement technologies. This robustness allows for accurate measurements even in environments where these conditions may fluctuate, reducing the need for extensive compensation or correction factors.

3. Wide Range of Applicability:

Thermal mass flow meters can be used across a broad range of gas flow applications. They are suitable for measuring the flow of various gases, including compressed air, natural gas, and specialty gases. This versatility makes them valuable in industries such as pharmaceuticals, petrochemicals, automotive, aerospace, and more.

4. Low Pressure Drop:

Thermal mass flow meters typically have a low-pressure drop across the sensor, minimizing the impact on the system being measured.

 

As technology continues to advance, these instruments are likely to play an increasingly integral role in optimizing processes and improving overall efficiency.

 

CONTACT US FOR MORE INFORMATION

Tags: Thermal Mass Flow Meter

Teledyne Hastings Employee Spotlight: Lawrence Ferbee

Posted by Doug Baker on Fri, Sep 22, 2023 @ 09:35 AM

Hastings Employee Spotlight_Lawrence Ferbee_Socialal Media Image

Time for another blog in our “Employee Spotlight Series”. This time we will meet Lawrence Ferbee. “Ferbee” is part of our awesome stockroom crew. He is primarily responsible for receiving products. But you can often find him at the stockroom window helping an employee with inventory. He also will, on occasion, help with our marketing projects. He has done live drawings for product videos as well as create cartoon characters for HR.

Let’s get to know him better.

Tell us about your start at Teledyne

I have been here since 2015. Prior to Teledyne Hastings, I worked in a similar role at Jefferson Lab (Department of Energy) in nearby Newport News Virginia. I knew a couple of managers that worked at Teledyne and when they told me about the position here, I jumped at the chance to get started.

Many folks here at the plant know you for your drawings.  How did you get involved in art and design?

I started drawing when I was six years old or so. I was an only child and doing art was a way for me to occupy my time. My art projects sort of kept me company. I am self-taught and I always enjoy seeing other things that artists are creating and sometimes, they inspire me.

We have always enjoyed the Holiday Cards you’ve helped to create as well as the giant chalk drawings. Is there a particular art piece that you are most proud of?

After thinking about it, I’m proud of all my works because people were happy with them. But I am working on something new that I’m very proud of because it involves that community that I grew up in.

Here are some examples of the work he has done for Hastings.
Teledyne Hastings Holiday 2022 Hastings Holiday family drawing
Hastings Earth Day Poster 2022

Sleigh with Rooftops

Piezoresitive sensor cartoon

What will he draw for us this year?  Put your ideas / suggestions in the comment box below

Whose artwork has had the biggest influence on you?

I grew up watching Hanna-Barbera action cartoons like Johnny-Quest and Space Ghost. When I was a kid, I really hoped to get a job with them. As I got older, I became more into comic books. Jim Lee is still one of my favorites.

What is your favorite part of working here at Teledyne Hastings?

I like the fact that I know everybody here and we have a family environment. I enjoy supporting people and, in my role in the Stockroom, I put my hands on almost everything that comes into the building.

To learn more about Teledyne Hastings and the products we make, visit our website or click below. 

CONTACT US FOR MORE INFORMATION

 

 

Tags: Employee Spotlight

Teledyne Hastings Employee Spotlight: Joshua Settle

Posted by Doug Baker on Wed, May 17, 2023 @ 02:04 PM

Hastings Employee Spotlight_Josh Settle_Socialal Media Image

In the second blog of our “Employee Spotlight” series, we focus on one of our engineers, Josh Settle. Josh works to design, test, and implement the electronics for our new products. In addition, he is a valuable resource to our production teams. He is also a member of our Quality System’s Internal Audit Team.

 Let’s ask Joshua some questions to get to know him better.

Let’s start with a history of your time here at Teledyne
I started summer 2014 as an electrical engineering intern. I didn’t know if I would get the internship, so I picked up another part time job as a lifeguard. I landed the internship later and kept working both. I put in 40 hours at Hastings during the week and 10-16 hours at the Mt. Trashmore Family YMCA on the weekend.

At Hastings I really enjoyed the people I worked with (I still do), and I am thankful for the ways they have invested in me (they still do). I interned again summer 2015 and came back month after undergrad to work full-time. My full-time start date was June 6, 2016. I celebrate 7 years with Hastings this summer.

 

Tell us a little about your educational background
I completed my Bachelor of Science in Electrical Engineering (mathematics minor) Magna Cum Laude from Virginia Tech in May 2016. That autumn, I immediately began working on my Master of Engineering Degree (Electrical and Computer concentration) at Old Dominion University while working full time. I finished my second degree in the spring of 2022. 

As far as concentrations go, I have always enjoyed mathematics for its brutal objectivity, intense precision, and its numerous tools used to help people observe reality and make meaningful changes.

 I also enjoy transmission line theory, an arcane field where material properties, geometry, circuit analysis, and electromagnetics all converge. I’m particularly interested in microstrip line distributed element filters (see the Distributed-element filter Wikipedia page). This subject has interesting applications because of its similarity to traces on a circuit board. As part of my second degree, I developed a python program that calculates the dimensions of one of these filters based on user input frequency characteristics and compared my program to a professional software package.

 

Hastings Joshua SettleWhat do you do here at Teledyne Hastings?
Short Answer: I solve as many problems as I can, learn from failure, and try to acquire useful skills along the way.

 

Long Answer: I help the engineering department meet long term goals especially with respect to new product development. I also help with production, repair, quality, tooling, and training needs.

 

I do everything from working on production benches, configuring tests, interpreting data, leading or supporting internal audits, assisting with technical documentation needs (drawings work instructions, procedures), or even being a liaison between multiple departments (production and sales, production and other engineers).

  

What are some of your outside interests?
I enjoy fitness, videogames, pizza, and red wine (dark, full-bodied, and dry).

 

Quote that we might use from you?
“Think things through. Consider the extremes. Speak carefully. Challenge your assumptions. Relax, and don’t be afraid to say, “I don’t know” or ask for help.

To learn more about Teledyne Hastings and the products we make, visit our website or click below. 

CONTACT US FOR MORE INFORMATION

 

 

Tags: Employee Spotlight

Nitriding of Steel Using Mass Flow Control of Ammonia

Posted by Doug Baker on Wed, Apr 26, 2023 @ 03:02 PM

Hastings Nitriding of Steel with Mass Flow Blog Social Media Image

Teledyne Hastings’ Mass Flow Controllers (MFC) are used in a very wide range of applications in numerous markets. In this blog, we are going to briefly explore the use of Teledyne MFCs to improve the surface properties of certain metals such as steel. Nitriding, in which a nitride layer is added, can also be used on aluminum and titanium.

There are three methods of nitriding: gas nitriding, salt bath nitriding, and plasma nitriding. (“Nitriding”, Wikimedia Foundation, 1/18/2023, https://en.wikipedia.org/wiki/Nitriding ). We are going to focus solely on gas nitriding. In this process, ammonia gas flow can be controlled into a furnace at several hundred degrees Celsius. The furnace is hot, but not so hot as to risk damaging or structurally modifying the part. Now the incoming gas can be controlled using a high-capacity mass flow controller. After the gas is admitted, the ammonia molecules (NH3) from the gas dissociates into nitrogen and hydrogen at the surface of the part being treated. The monatomic nitrogen can then diffuse into the surface of the part and form a nitride coating layer.

Ammonia_NH3

What are some of the benefits of nitriding? First, the treated part will generally have an increased hardness which in turn will give the part improved wear resistance. Also, many parts that have been treated with the nitride process will be less susceptible to corrosion.

There are many types of parts that are given nitride treatment.

  • Gears and splines
  • Shafts and bearings
  • Valve components
  • Extrusion dies
  • Rollers for continuous crimping

Hastings parts collage

In large furnaces, high flows of ammonia gas are required, and Teledyne is able to supply mass flow controllers that are accurate, stable, and fast. We are ready to help. Contact us and we will help you size a flow controller for your nitride application.

image-png-1

 
A Series shown with IP-67 B Series shown with touchscreen

“A” Series shown with IP-67

“B” Series shown with touchscreen

In addition to our analog 200 Series mass flow controllers, we can also provide our Digital 300 Series (“A” and “B” Models) which feature excellent accuracy ± (0.2% full scale + 0.5% of reading) , fast response, and flexibility. “A” models can be built with IP-67 enclosure which offers protection against external dust and liquids. “B” models can be configured with an optional color touchscreen display. Both “A” and “B” models provide digital and analog (0-5 VDC, 0-10 VDC, 0-20 mA, 4-20 mA) input and output. Both have internal totalizer feature so the user can track the total amount of ammonia gas used in a nitride heat treat cycle. Free user software is provided (but is not required) and, for LabVIEW users, free certified drivers are available from ni.com.

If you have a nitride process or any other application that requires precision gas control, we would very much like to hear from you. You can contact us by phone (757-723-6531), email (hastings_instruments@teledyne.com) or via LiveChat at www.teledyne-hi.com  

CONTACT US FOR MORE INFORMATION

 

Tags: mass flow controller

Employee Spotlight - Will Harrison

Posted by The Teledyne Hastings Team on Thu, Feb 02, 2023 @ 09:45 PM

Hastings Employee Spotlight_Will Harrison_Social Media ImageWe are starting a new blog series where we will introduce you to some of the key employees here at Teledyne Hastings. Our first blog in this series will focus on our domestic sales manager, Will Harrison.

In addition to being domestic sales manager, Will works as a sales application engineer ensuring that customers select the best flow or vacuum product for their application/system. Will also works with our USA channel partners and keeps them informed of the latest products and markets for Teledyne Hastings’ products and services. Will has been with Teledyne for over thirty-five years.

 Let’s ask Will some questions to get to know him better.

 

  • How did you start working at Teledyne Hastings? 
    I had a close friend that worked here who mentioned the expanding sales team was looking to hire a new sales application engineer. It seemed to happen very fast … I applied, was interviewed, and was hired in less than two weeks.

 

  • What is a typical day like for you?
    I am always available for customer phone calls. I enjoy hearing about new opportunities or helping customers improve an existing vacuum or flow application. When not on the phone, you might find me generating a quote for a customer or helping out one of our USA sales channel partners. I also travel with our distributors as we look for new opportunities for Teledyne Hastings.

 

  • Let’s follow up on that, where is one of your favorite places where you have for traveled for work?
    The best place I ever traveled was Vancouver BC. Vancouver is a neat place to venture out, see the sites, and enjoy great food. Our distributor drove us up to see Whistler, which was awesome! At the time, that area had a few startup companies focused on the fuel cell industry and our mass flow meters and controllers were enjoying great success.

  • Outside of work, what is it that you like to do?
    I like to run and bike when time permits. I like to do half marathons and full marathons. I’ve even completed a full “ironman” triathlon. I also enjoy Old Dominion University (ODU) sports where I got my degree. The Lady Monarchs won back-to-back national titles in women’s basketball (1979, 1980) before the NCAA became involved. The excitement from the crowds at the ODU sporting events is great.

  • What is one part of the job that you find rewarding? 
    I enjoy working with our sales channel partners and customers to provide solutions for a wide variety of applications. I also enjoy working with my colleagues on the sales team and other members of the Teledyne Hastings Team.

 

In this series, we hope that every reader will be able to learn a little more about the employees they interact with here at Teledyne Hastings. If you call for support or sales, we all have a story and we would like to share that story with you.  Visit  https://info.teledyne-hi.com/blog to read more about our vacuum gauges and mass flow meters and mass flow controllers. (And look for future postings about Teledyne Hastings’ employees.)

 

Will MarathonWill Harrison (right) after finishing the 2022 Honolulu Marathon. Brother Glen is on the left.

To learn more about Teledyne Hastings and the products we make, visit our website or click below. 

Contact Us

Tags: Employee Spotlight

Windows-based User Software for Teledyne Hastings’ Mass Flow and Vacuum Instruments

Posted by Doug Baker on Mon, Sep 26, 2022 @ 04:33 PM

Hastings Window Based User Software_Blog Social Media ImageTeledyne Hastings has a broad offering of thermal mass flow meters, mass flow controllers, and vacuum instruments. Within each of our digital product families, we offer both analog output (e.g. 0-5 VDC, 0-10 VDC, and 4-20 mA) and digital outputs (RS232, RS485, and USB). Typically, our customers will interface our instruments to their data acquisition systems. But, in some cases, our users want a fast and easy method to configure, control, and collect data with our instruments. In this blog, we will discuss our Windows-based programs. Specifically, we will answer three questions:

  1. Vue Touch ScreenWhat do our Windows-based interface programs do?
  2. How do you use the Windows software?
  3. Where can I download the Teledyne Hastings free Windows user software?

Before we start, we want to tell you that all of our instrument software, including DisplayX for the THCD-101 and THCD-401 power supplies, is FREE. We don’t charge for these routines so there is a limit to how much technical support we provide for software. But, if you run into an issue, we will try to help. Typically, software issues are associated with the PC and not with the flow or vacuum instrument.

 

1. What do our Windows-based interface programs do?

CONFIGURATION: Our instruments are configured and shipped according to the selections given to us before order entry. Generally, our instruments are “plug and play”. But in some cases, the end-user may decide that they want to change the configuration. For example, it may be the case that a different set of units is more convenient. Or, in the case of a flow instrument, a different gas record needs to be selected. Our Windows-based code makes it very easy to make a selection and write it to the instrument’s memory. Our Digital 300 Series has many features including multiple gas record capability, totalizer, and control valve soft-start. All of these can be modified with our free Windows-based user software.

CONTROL: In some cases, the user may want to get up and running very quickly to test system parameters before they interface to a PLC. Our routines allow easy control and the user has the option to open a window to view live vacuum or flow data as a function of time. And the user can display a graphical window which shows performance over a stretch of time. In the case of a flow controller, the user can enter flow setpoint commands using a numeric input, or slider bar.

Data Logging: Perhaps the most popular use of our Windows-based programs is the ability to set up and record data to an Excel (csv) file with a user-defined interval over a long period of time. This allows the user to perform tests overnight or over several days. There is a limit to the number of data points that can be stored. So the user must take that into consideration when setting up the test.

2. How do you use the Windows software?

For starters, you will need to connect a serial cable (RS232, RS485, or USB) from your laptop to either the 300 Vue mass flow instrument or our HVG-2020 vacuum gauge. In this example, I will connect to an HFC-D-302B digital mass flow controller. But, the initial steps are identical for the HVG-2020 Series vacuum gauges. A USB cable (micro-B) is very convenient to use because these cables can usually be found at “dollar” stores. (And yes, they only cost about a dollar.) The USB connector serves as a virtual COM port for serial communication, eliminating the need for a USB to Serial converter.

Once connected, you simply run the Windows executable program and the following window will popup:

Windows program

At this point, you need to serially connect to the instrument. You do this by clicking on Operation

Windows Operationand then clicking on Connect

Windows Connect

Now, in the case shown here, my cable is connected to COM Port #4 and when I select COM4 in the drop-down menu, the window shows the digital setpoint (in blue) and the actual flow rate (in red).

Windows COM4

Once the unit is connected, there are several additional windows that can be opened. You can click on VIEW and see the choices.

Windows View

If you are operating a flow controller, the next window you will likely want to open is SetPoint. This window allows you to control the MFC by typing a setpoint command in the entry field at the top, sliding the selector on the left, or clicking one of the boxes on the right.

Windows Setpoint

The Operation menu has many useful features, especially for configuring the 300 Vue mass flow controller. And, if you want to log data over a long period of time, you will set that up using the Logging menu.

Windows Operation Logging

 

3. Where can I download the Teledyne Hastings free Windows user software?

You can request the software from our website. The link is given here: https://www.teledyne-hi.com/resource-center/software

Please note that we must comply with US export regulations, so we are required to know the names and addresses of all folks who request our software. Once you have completed the short form and we have reviewed, one of our application engineers will send the requested software to you via a secure file transfer site.

One other note we would like to make about digital communication with our vacuum and flow products. In addition to the Windows software, we also have certified LabVIEW drivers for all of our digital products. And for our flow power supplies (THCD-101 & THCD-401), we provide free software (DisplayX).

HVG 2020A_Torr

300 Vue Mass Flow LabVIEW Driver – Click Here

HVG-2020A Vacuum Gauge LabVIEW Driver – Click Here

HVG-2020B Vacuum Gauge LabVIEW Driver – Click Here

DCVT Vacuum Gauge LabVIEW Driver – Click Here

DAVC Vacuum Gauge LabVIEW Driver – Click Here

THCD-101 Flow Power Supply LabVIEW Driver – Click Here

THCD-401 Flow Power Supply LabVIEW Driver – Click Here

And as always, we are here to help. If you have any questions about any of our vacuum or flow products, you can reach out to us by phone (800-950-2468/757-723-6531), email (hastings_instruments@teledyne.com) , or via LiveChat on our website (www.teledyne-hi.com )

 

Microsoft, Windows, Internet Explorer, Microsoft Edge, OneDrive, and Microsoft Excel are trademarks, or registered trademarks of Microsoft Corporation in the United States and other countries.

Fittings for Mass Flow and Vacuum Instruments

Posted by Doug Baker on Mon, Jun 20, 2022 @ 02:48 PM

Choosing Your Fittings_Blog Social Media ImageIn this blog, we will discuss various system connections, or fittings, that are available for both our mass flow and vacuum products. We will briefly explore why you might select a particular family of fittings for your system. Also, we will touch on some basic installation Dos and Don’ts.

 

Mass Flow Meters and Mass Flow Controllers

Many users of low flow (0-5 sccm up to 0-25 slm) instruments appreciate the convenience of compression fittings. The Swagelok ™ brand of compression fittings is very popular, and many users ask for these by name. Compression fittings can be very reliable; also, they can be quickly uninstalled and reinstalled as needed. And, unlike VCR ™ and VCO ™ fittings (we will talk more about these in a minute), compression fittings do not require a separate o-ring or single-use gasket. Our flow products are offered with various size Swagelok™ brand compression fittings. While the 1/4” size is the most popular for many low flow applications, we also offer, even smaller, 1/8” size as well. Metric sizes, including 10 mm and 12 mm, are also available. Then, for even higher flow applications, we also offer 1/2”, 3/4”, 1”, 1.5” and even 2” Swagelok ™ fittings. Note that the largest compression fittings require a swaging tool. (Link?)

Per the “Tube Fitter’s Manual” published by Swagelok®, here are the steps for manual installation of Swagelok Tube Fittings up to 1 in. or 25 mm.

  1. Fully insert the tube into the fitting and against the shoulder; rotate the nut finger tight.

    Swagelok Tube Fitting - insert tube into fitting
  2. Mark the nut at the 6 o’clock position.

    Swagelok Tube Fitting - mark nut at 6 oclock

  3. While holding the fitting body steady, tighten the nut 1 ¼ turns to the 9 o’clock position.
    For 1/16, 1/8, and 3/16 in. or 2, 3, and 4 mm tube fittings, tighten the nut ¾ turn to the 3 o’clock position.

    Swagelok Tube Fitting - tighten nut

Reassembly Procedure is as follows:

  1. Prior to disassembly, mark the tubing at the back of the nut, mark a line along the nut and body flats. Use these marks to ensure that you return the nut to the previously pulled-up position.

    Swagelok Tube Fitting - mark tubing
  2. Insert the tubing or tube adapter end connection with pre-swaged ferrules into the fitting until the front ferrule seats against the fitting body.

    Swagelok Tube Fitting - insert tubing
  3. While holding the fitting body steady, rotate the nut with a wrench to the previously pulled-up position, as indicated by the marks on the tubing and flats. At this point, you will feel a significant increase in resistance. Tighten the nut slightly.

    Swagelok Tube Fitting - rotate nut

The VCR ™ system from Swagelok™ is very popular with users who need high purity, all-metal, reliable sealing for either positive pressure or vacuum applications. For these fittings, a gasket, usually metal, is used to seal between the two symmetric sealing faces. In some cases, an elastomeric or PTFE gasket can be used. Metal gaskets (e.g. copper, nickel, or stainless steel) in VCR ™ connections should only be used once. Metal gaskets can be purchased with a retainer to hold the gasket in place when installing. The gasket is secured between the mating surfaces and the nut is drawn finger tight. Then, to finish installation, two wrenches are used to tighten the connection and create the leak-free seal. Note that copper gaskets require a 1/4 turn (90°) beyond finger tight while nickel and stainless steel only require an 1/8 (45°) of a turn.

HFC-302 with VCR fittingHFC-302 with VCR fittings

 

Live chat

The VCO™ system is convenient when the user wants to have fast make and break connections. It is also handy when space is limited. One part of the VCO™ connection includes an o-ring while the mating connection has a flat smooth finish. Installation is easy. A nut is made finger tight and then a wrench is used to tighten by 1/8 (45°) of a turn.

Usually, your fitting selection and piping are going to be a function of the flow rate. Our application engineers are available via email, phone or LiveChat to help you.

 

 

Vacuum Gauges

There are several popular systems of connections for vacuum gauges. Selection of a system should be driven by base pressure, outgassing load, and of course, cost.

For many users who just need to reach the mTorr range of pressures, tapered pipe thread (NPT: National Pipe Tapered) connections are simple, require no external clamps or bolts, and can be assembled quickly. However, PTFE tape or some other sealant should be used on the threads for two reasons. First, the tape/sealant fills the void between the mating thread surfaces and second, the tape/sealant acts as an anti-galling lubricant between the threads.

When wrapping PTFE tape onto NPT threads, start with clean surfaces and a clean cut of the tape. Make sure the tape is flat as it is wound onto the sealing surfaces and wrap in the direction of the threads. Two to three wraps is adequate. End the wrap with a clean cut of the tape. Tighten the connection with a wrench. How tight? Well, there is no right answer except to say that you want the system to seal, but you don’t want the threads to strip. So, use a wrench until tight, but do not try to force and overtighten.

The KF system is convenient for users who need a fast leak tight system connection for their vacuum gauges. “KF” is short for Klein Flansche which is German for small flanges. Vacuum systems with KF flanges can reach into the 10-8 Torr range. KF sizes, such as KF-16 and KF-25, are related to the maximum nominal inner diameter tubing in millimeters that can be attached to the flange.

DV-6-KF-16Teledyne DV-6-KF-16 (Shown with o-ring assembly and clamp)

 

And lastly, ConFlat hardware is ideal for high vacuum and ultrahigh vacuum systems. ConFlat flanges have a knife-edge that seals against a gasket, usually copper. The connection is made by tightening a series of bolts; the number of bolts is a function of the size of the flange. Clean, baked, suitably pumped systems using ConFlat hardware have been known to reach pressures below 10-13 Torr.

DV-6 Gauge Tube with ConFlat FlangeDV-6 Gauge Tube with ConFlat Flange

 

If you would like to discuss your application for vacuum gauges, mass flow meters, or mass flow controllers, we are standing by. You can reach us by phone (1-800-950-2468), email (hastings_instruments@teledyne.com) , or by using our LiveChat box at www.teledyne-hi.com or clicking on the box below.

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Note: All photos of Swagelok fittings in this blog are used with their written permission.

Tags: mass flow controller, mass flow meter, mass flow instruments

Argon gas (Ar) Applications – Accurate Vacuum Measurement and Flow Control

Posted by Doug Baker on Mon, Mar 28, 2022 @ 11:30 AM

Argon Gas Applications_Blog Social Media ImageThis blog is the next installment in a series focusing on industrial gases. The first blog featured SF6 and can be found here:   http://info.teledyne-hi.com/blog/sulfur-hexafluoride-gas-sf6 . The second blog focused on carbon dioxide (CO2): https://info.teledyne-hi.com/blog/carbon-dioxide-co2 . Now we will take a look at Argon.

Argon (Ar) makes up just under 1% (0.93%) of the composition of air. Argon is odorless, tasteless, and has no color. It is a member of the noble gases. Science Notes (sciencenotes.org ) gives an interesting history of the term, “Noble gas”:

The term “noble gas” comes from a translation of the German word Edelgas, which means noble gas. German chemist Hugo Erdmann coined the phrase in 1898. Like a nobleman might consider it undignified to associate with commoners, noble gases tend not to react with other elements.

In any case, noble gases such as Argon are found in the right-hand column of the periodic table which means they have completed valence shells. The noble gases are generally monatomic and are mostly inert. The word “argon” comes from the Greek word “argos” which, according to Webster’s dictionary, means “idle, lazy.” This definition makes sense because Argon gas is quite unreactive and rarely forms compounds.

Because of its inert behavior, Argon gas has many uses. One of the most popular is the use of Argon as a cover gas when welding. A flow of Argon can provide an inert environment which prevents oxidation of welds and also allows the welder to have a more stable arc.

Argon is also used in the medical field. Argon plasma coagulation can be used to control tissue bleeding by injecting a jet of ionized argon gas. Also, since the physical probe does not have to actually touch the lesion, the procedure can be safer than other techniques. In ophthalmology, Argon lasers can be used to treat issues with the retina.

Many homes have double-pane windows filled with Argon gas. Argon provides better insulation than air because it allows less convection between the windowpanes. And because Argon is inert, it prevents deterioration of the window materials.

In lighting, an Argon glow discharge provides a pleasant purple-blue color. And in tungsten incandescent bulbs, a small amount of Argon is used to extend the bulb’s life.

Argon can also be used when making wine. In the wine’s casket or barrel, above the wine, is the headspace. Filling the headspace with Argon gas protects against oxidation and spoilage.

We could keep going in this blog and list many more applications. But we will stop this list with reference to a blog that we wrote back in 2018. The Emancipation Proclamation is stored in a double-paned encasement, designed by scientists at NIST, that that is mostly filled with Argon. You can read more here: https://info.teledyne-hi.com/blog/how-monitoring-instrumentation-is-helping-preserve-the-emancipation-proclamation

Hastings Argon Blog Collage

And, of course, when you need to measure Argon flow or vacuum levels with Argon, Teledyne Hastings is ready to help. Our flow instruments are able to measure and control flows from a few sccm (standard cubic centimeter per minute) up to several thousand slm (standard liters per minute).

Teledyne vacuum gauges are very good selection for use in Argon. The HVG-2020B (Click Here) is an excellent choice for measuring Ar from below 1 mTorr up to atmosphere. Convection driven pirani vacuum gauges, when used with gases other than N2/air can have curious behavior as can be seen in the cartoon below.

Convection driven pirani vacuum gauges cartoon

The HVG-2020B vacuum gauge uses a gas-independent piezoresitive sensor that does not rely on convection affects and provides a more linear response to Argon across the entire measurement range.

Piezoresitive sensor cartoon     HVG 2020A_76307_finger

If you would like more information about either the 300 Vue mass flow meters or controllers, or any of our vacuum gauges including the HVG-2020B, you can talk to any of our application engineers at 757-723-6531, email hastings_instruments@teledyne.com, or LiveChat with us at www.teledyne-hi.com

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Special thanks to Lawrence Ferbee from the stockroom for his cartooning skills. If you would like to see Lawrence in action as he draws, check out our HVG-2020B video:

https://www.youtube.com/watch?v=_Bk3Q7SpSUc

 

Tags: Argon Gas

What is a Pirani Vacuum Gauge?

Posted by Doug Baker on Wed, Dec 01, 2021 @ 10:44 AM

A Pirani vacuum gauge is a type of thermal conductivity gauge that is also often referred to as a “thermal heat transfer gauge”. In a Pirani gauge, the rate of heat transfer is a function of the number of gas molecules present in the vacuum system. Pirani gauges are capable of providing reliable pressure measurement in a wide variety of vacuum technology applications.

What is the working principle of the Pirani Vacuum Gauge?

Pirani GaugeA Pirani vacuum gauge contains a heated component, such as a wire or thin-film membrane (see figure on right), which is brought to an elevated temperature, typically through the use of a bridge circuit. As changes in gas molecular density occur, the transfer of heat from the wire to the gas is affected. This heat loss is dependent on gas type and pressure, and the amount of energy required to keep the wire at temperature varies accordingly. Consequently, the amount of energy is dependent on vacuum pressure and can be converted to a pressure value.

Accurate pressure measurement depends on the ability of the bridge circuit to maintain very precise control of the sensor’s temperature. The most common technique is to use a Wheatstone bridge circuit. In one design of a Pirani bridge circuit, two legs of the bridge are controlled at the same voltage via an electronic feedback loop. The measurement technique then is to quantitate the power required to maintain the heated sensor at a given temperature above ambient. (See J. Vac. Sci. Technol. A 13(6), Nov/Dec 1995)

In the case of a gauge that employs a heated sensor wire, there are three main heat loss routes: bulk thermal conduction via the wire and its supports, radiation losses, and thermal conduction losses through the gas. It follows that a well-designed Pirani vacuum gauge minimizes loss of signal due to radiation and bulk thermal conduction. Radiation losses are strongly (fourth power) dependent on the temperature of the heated sensor. Consequently, when operating a Pirani gauge, it is important to keep the sensor at a low enough temperature such that the radiation loss mechanism does not dominate the overall signal. Similarly, a well-designed Pirani gauge minimizes bulk thermal conductivity via the sensor element. For both radiation and bulk thermal conductivity losses, the loss factors are dependent on temperature.

What are the advantages of the Pirani Vacuum Gauge?

The Pirani vacuum gauge offers numerous advantages. Foremost, the gauges are typically very easy to use and can provide years of trouble-free, reliable pressure measurement, because they have no moving parts. Additionally, they are highly economical, costing far less than capacitance manometers. Flexibility in output monitoring includes local displays, analog output, and/or digital communication. Pirani vacuum gauges are relatively fast and are very responsive to changes in the vacuum system’s pressure. Gauges with very small internal dimensions can offer increased response speed. It should be noted that convection-enhanced Pirani vacuum gauges require larger volumes to support convection currents and may therefore have slower response, simply due to the larger volume that must be evacuated inside the tube. Convection-enhanced Pirani vacuum gauges measure pressure up to atmospheric pressure, however, their accuracy in gases other than air or nitrogen at elevated pressure, can be very poor.

Combination gauges, such as Teledyne Hastings’ HVG-2020B, combine a piezo-based sensor with a conventional, thermal-based Pirani sensor to provide accurate pressure measurement from 10-4 Torr (0.1 mTorr) to 10+3 Torr.  Additionally, by combining the two technologies in one gauge, the errors associated with the gas composition specific Pirani sensor are eliminated at pressures above 10 Torr.

What are some of the applications for Pirani Vacuum Gauges?

Many Pirani vacuum gauges measure pressure from below 1 mTorr up to atmosphere and are a very good choice for a wide variety of applications:

  • Pirani vacuum gauges are used to monitor the pump down from atmosphere to the start of the high vacuum region (where turbomolecular pumps or other high-vacuum pumps take over)
  • In the vacuum metallurgy industry (high-purity alloys manufactured in a controlled environment) Pirani vacuum gauges ensure process consistency and optimization of different thin-film coating systems.
  • Freeze dryers and vacuum dryers frequently operate in a vacuum region that is well-suited to Pirani vacuum gauges, as well as the manufacture and maintenance of cooling systems (air conditioning, ice machines, and refrigeration).
  • Various analytical instrumentation requires vacuum levels in and below the mTorr region, and the Pirani gauge is often the most cost-effective instrument for these applications.

FAQs

What are some best practices for Pirani Vacuum Gauges?

Pirani gauges have no moving parts and generally do not require maintenance. It should be noted that this type of gauge is susceptible to contamination, especially in oil-based pumping systems. In systems with contamination, the gauge tube should be installed with the port facing downward to reduce oil accumulation inside the tube. 

Convection-driven Pirani vacuum gauges should always be installed with the cylindrical axis parallel to the floor. Failure to install this type of gauge properly will lead to erroneous readings above the rough vacuum level. 

If the vacuum system has excessive oil vapor or other contaminants, a molecular sieve filter can be used to extend the service life of the gauge.

For information on Teledyne Hastings Vacuum Gauges, visit https://www.teledyne-hi.com/products-services/vacuum-measurement-and-control or click the button below to contact us for more information.

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Tags: Pirani Vacuum Gauge