Teledyne Hastings Instruments Blog

In cryogenic applications, especially those mounted on trucks, railcars, and ISO containers, vessels face some of the harshest mechanical and environmental conditions in industry. Because these tanks are in motion, often over uneven terrain or long rail routes, the vacuum sensor must be reliable and remain accurate despite constant vibration. Vibration, shock, temperature swings, and outdoor exposure all place immense demands on sensors tasked with delivering reliable vacuum measurements.

Teledyne Hastings Instruments’ DV-6S Thermocouple Gauge Tube was purpose-built to thrive in these environments. Below is a deep dive into what makes the DV-6S uniquely suited for mobile cryogenic vessels.

Engineered for Extreme Ruggedness

Photo courtesy of NCEE Labs (Nebraska Center for Excellence in Electronics)

The DV-6S isn’t just a more durable version of our DV-6R ruggedized vacuum gauge tube. It was specifically designed and tested to extensive MIL-STD levels to withstand severe shock and vibration consistent with road vibration, rail line harmonics, and loading/unloading impacts.

• Mechanical Shock: MIL-STD 202 Method 213 (>2,000g for 6 ms duration)
• Random Vibration: MIL-STD 202 Method 214
  (23.9 grms)
• Sinusoidal Vibration: MIL-STD 202 Method 204
  (30g at 3,000 Hz)

These specifications exceed what real-world applications encounter, making the DV-6S ideal for equipment subjected to continuous road, rail, or ship movement.

Corrosion Resistant for Harsh Outdoor Installations

In transport environments, moisture and debris can compromise vacuum sensor performance and reduce lifespan. The DV-6S combats this with:

• Rugged stainless steel housing built for outdoor environments
• Protective O-ring-sealed aluminum cap to:
  • Prevent moisture ingress and reduce corrosion of electrical pins
  • Protect pins and feedthroughs from foreign object damage
• Steel lanyard to prevent cap loss during field servicing

These design elements support long-term reliability even when the gauge is exposed to weather conditions typical of transportation applications.

Performance and Compatibility

Cryogenic vessels rely on vacuum jacketed insulation to maintain extremely low temperatures. A vacuum sensor like the DV-6S helps operators:

• Verify integrity of the vacuum jacket
• Detect insulation degradation in early stages
• Ensure safe transport of cryogenic liquids such as LNG, LN₂, LOX, LH₂, LAr, LCO₂ and other liquified gases

Despite the extremely robust design, the DV-6S maintains the same trusted measurement performance as other DV-6 series vacuum gauge tubes:

• Measurement range: 0.001 to 1 Torr (1 to 1000 mTorr) which is the standard DV-6 Series measurement range
• Fully compatible with Teledyne’s DV-6 Series Instruments like the portable handheld HPM 4/5/6 gauge and others such as the DCVT, DVT, VT-6A, and DAVC.
• 1/8" male NPT connection is standard with options available for KF-25, KF-16, KF-10, and ¼ VCR.

This ensures operators can incorporate the DV-6S into existing systems without redesign, making fleet-wide adoption simple and cost effective.

The Clear Choice

The Teledyne Hastings Instruments’ DV-6S stands out as a purpose engineered solution for mobile cryogenic vessels. It’s the go-to vacuum sensor for LNG fuel tanks on gas powered trucks. With its extreme shock and vibration performance, rugged outdoor ready design, and precise vacuum measurement capabilities, it delivers reliability in environments where other sensors fail.

For cryogenic equipment manufacturers and fleet operators alike, the DV-6S offers confidence, safety, and long-term durability – everything needed to keep critical cryogenic systems performing during transport.

Note: A DV-5 Series version is also available. The DV-5S offers the same extreme protective features as the DV-6S but covers the DV-5 Range of 0.0001 to 0.1 Torr (0.1 to 100 mT). It’s also compatible with the handheld HPM 4/5/6 vacuum gauge.

Visit https://www.teledyne-hi.com/en-us/what-we-do/dv6-series to learn more about the DV-6S vacuum gauge tube.

If you have questions about vacuum gauges or vacuum controllers, feel free to contact us by phone (+1-757-723-6531 or 1-800-950-2468), email Hastings_Instruments@Teledyne.com, or via Live Chat on our website www.teledyne-hi.com.

Vibration test photo provided by NCEE Labs (Nebraska Center for Excellence in Electronics): nceelabs.com : Tel 402-323-6233

We at Teledyne Hastings Instruments are pleased to introduce the newest member of our vacuum measurement portfolio, the HVG_PR. The HVG_PR vacuum gauge measures pressures from Atmosphere to 0.1 mTorr (1.3 x 10^-4 mbar / 1.3 x 10^-2 Pascal). It uses the same precision pirani sensor found in our proven HVG-2020B wide range gauge. The HVG_PR is packaged in a compact and cost-effective design that makes it ideal for OEMs, system integration, and process automation.

Accuracy

The HVG_PR measures from Atmosphere through Medium Vacuum (0.1 mTorr / 1.3 x 10^-4 mbar / 1.3 x 10^-2 Pascal). It has great accuracy from 1 mTorr to 100 mTorr while still providing visibility at atmosphere. Most applications use N2 or Air, but the HVG_PR has preset gas correction factors to also cover He, Ar, H2, CF4, and SF6.

System Connections

The HVG_PR is available with two small system connections for system integration: KF-16 flange or 1/8” MNPT. Unlike some pirani vacuum gauges, the HVG_PR can be mounted and operate in any orientation: port facing down, port facing up, port facing sideways, port tilted at an angle, etc.

Analog Output and Digital Communication

Both models offer two choices of common logarithmic analog output signals for simple integration into OEMs and process automation: 1 V/decade (2-9 VDC) or 1.286 V/decade (1.16-10.1620). The user can easily change from one output to the other. In addition, RS485 digital communication is standard on all units. Power, analog output, and digital communication are provided through a single RJ45 connector.

Other Features

A status LED on the top panel flashes to allow you to approximate your pressure with a quick glance.

The gauge offers three simple ways to Zero or Span the unit:

1. Recessed Push Button,

2. Remote Pins 7 & 2

3. RS485

Applications

The HVGPR is ideal for a wide variety of vacuum applications, but it’s compact size and flexibility make it excellent for OEMs, system integration, and process automation.

Common Analytical Instrumentation OEM applications include but are not limited to:

• Vacuum Centrifuge
• Surface Porosity
• Optical Emission Spectrometers
• High Pressure Metrology

Other common applications include:

• Semiconductor
• Foreline Monitoring
• Glass Coating
• Thin Film Deposition
• Freeze Drying
• Vacuum Furnace / Heat Treat
• HVAC / Refrigeration / Ice Machinery
• Oil Reprocessing 

Visit https://www.teledyne-hi.com/en-us/what-we-do/hvg-pr to learn more about the HVG_PR vacuum gauge.

If you have questions about vacuum gauges or vacuum controllers, feel free to contact us by phone (+1-757-723-6531 or 1-800-950-2468), email Hastings_Instruments@Teledyne.com, or via Live Chat on our website www.teledyne-hi.com.

This is the third blog in our series highlighting Teledyne Hastings Instruments’ authorized service partners. These partners are fully authorized to calibrate and repair Teledyne Hastings Instruments’ vacuum gauges, mass flow meters (MFMs), and mass flow controllers (MFCs).

This service partner provides calibration and repair service for all of China as well as the Hong Kong and Macau SARs. Lets meet JeeGa!

Shanghai JeeGa Industrial Co., Ltd. was established in 2014 and is headquartered in one of China's largest cities: Shanghai. In addition, they have a branch office in Wuhan and operate in Hong Kong under the name HK Beimu. JeeGa has been a distributor of Teledyne Hastings Instruments since their start in 2014 and is one of Teledyne's most sophisticated distributors.

JeeGa stocks vacuum gauges, vacuum transducers, mass flow meters (MFMs) and mass flow controllers (MFCs) at their Shanghai site. Most common Teledyne Hastings Instrument products are readily available for quick local delivery. The DV-6R and HPM 4/5/6 products are stocked in extremely large quantities. Teledyne HFM-200 (MFMs) and HFC-202 (MFCs) are stocked in kit format. JeeGa can quickly configure, assemble and calibrate HFM-200 MFMs and HFC-202 MFCs to meet your exact gas type, flow rate and pressure requirements to ship these in a short lead time. All units are assembled and calibrated per Teledyne's standards and specifications. JeeGa has literally manufactured thousands of HFM-200s and HFC-202s in their Shanghai facility.

HFC-2020 MFC kits assembled and calibrated in Shanghai

JeeGa's calibration and repair lab has been in operation for approximately ten years. New calibration equipment is added each year to continuously grow the lab. JeeGa's Service Engineers can test and repair all of Teledyne's vacuum and flow products. These Teledyne factory-trained and certified technicians are capable of calibrating your instrument or repairing it quickly with genuine parts and up-to-date procedures as needed. Most calibration services are completed within 48 hours.

JeeGa has three calibration benches for MFMs/MFCs and one test stand for high vacuum calibration. The lab consists of multiple flow reference standards (Molbloc, DryCal, Teledyne), multiple vacuum reference standards (capacitance manometers), residual gas analyzers (RGA), helium leak detector and more.

Calibration Capabilities:

For more details about services offered by Shanghai JeeGa, please visit: https://www.jeega.com.cn/

Contact Details:

Email: wangxuemei@jeega.com.cn
Phone: +86 (21)-61179398
Address: Room 505, Building 18, 50 Smart Technology Park, No. 423 Wuning Road, Putuo District, Shanghai, 200063, China

For more information on calibration services for vacuum gauges, vacuum transducers, mass flow meters, and mass flow controllers provided by Teledyne Hastings Instruments, please check out: https://www.teledyne-hi.com/en-us/what-we-do/calibration-repair

This is the second blog in our series highlighting Teledyne Hastings Instruments’ authorized service partners. These partners are fully authorized to calibrate and repair Teledyne Hastings Instruments’ vacuum gauges, mass flow meters (MFMs), and mass flow controllers (MFCs).

This service partner provides calibration and repair service for the Republic of Korea as well as the large Asia-Pacific region (excluding China). Let’s meet InfoRAD!

InfoRAD Corp. was a part of Applied Engineering which became a distributor for Teledyne Hastings Instruments in 1983. Applied Engineering decided to spin-off InfoRAD in 2003, and InfoRAD immediately began the transition from a pure sales office to a complete sales, calibration, repair, and custom system design facility. They support customers across South Korea from their headquarters in the M-City Tower in Goyang. The office sits on Seoul’s northwest edge which is only 30 minutes to downtown Seoul and about 40 minutes to Incheon International Airport via expressway or airport rail. This convenient location facilitates fast deliveries, quick on-site visits, and smooth travel for visiting engineers. InfoRAD stocks vacuum gauges, vacuum transducers, mass flow meters (MFMs), and mass flow controllers (MFCs). This means you don’t have to wait for long overseas shipments.

InfoRAD has Teledyne factory-trained and certified technicians capable of calibrating your instrument or repairing it quickly with genuine parts and up-to-date procedures as needed. InfoRAD has a complete laboratory with flow reference standards, vacuum reference standards, helium leak detector, and more. 

Do you have too many instruments to ship?

The InfoRAD team will travel anywhere in Korea with portable standards and tools.

Calibration Capabilities:

Custom Flow and Vacuum Projects

From small flow and vacuum setups for universities and research labs to large gas delivery systems, gas mixing systems, and flow measurement test stands, InfoRAD engineers can design one-off systems built exactly to a customer’s specifications. Custom software and interfaces are also available.

For more details about services offered by InfoRAD, please visit: https://en.inforad.co.kr/ 

Contact Details:

Email: info@inforad.co.kr
Phone: +82-70-4640-2580
Address: #11007, Section-Bldg, M-City Tower, 195 Baengma-ro, Goyang-si, Gyeonggi-do 10403, South Korea

For more information on calibration services for vacuum gauges, vacuum transducers, mass flow meters, and mass flow controllers provided by Teledyne Hastings Instruments, please check out: https://www.teledyne-hi.com/en-us/what-we-do/calibration-repair

Teledyne Hastings Instruments manufactured several variations of the dependable model CVT vacuum controller for multiple decades. While they are obsolete now, a replacement is available. In most cases, the current model DCVT can fulfill the functions of your CVT.

The CVT was more than a basic vacuum gauge. It was a vacuum controller with setpoints and relays. You could use it to control a pump, a valve, an alarm, an indicator light, or almost any electrical device. The DCVT is also a vacuum controller, but it offers many more features. While the DCVT is dimensionally different and does look quite different, it still uses the same Teledyne Hastings Instruments’ DV Series thermocouple gauge tubes as the CVT. Whether you are using DV-4, DV-5, or DV-6 Series thermocouple gauge tubes, they will all work with the DCVT.

The following sections will assist you in replacing your CVT with the DCVT.

Choose the appropriate gauge:

To choose the appropriate gauge, select the one that corresponds to your thermocouple gauge tube series. Most are color coded for quick identification.

Dial Face vs Digital Display:

The obvious difference between the CVT and DCVT are their displays. The CVT provided a dial-face with needle movement. Some users liked to see the needle movement because the movement rate gave them a feel for their vacuum system’s performance. It also provided a quick-read indication when looking from across a room. While the DCVT does not have the dial-face and needle, it does provide a bright and easy-to-read digital display. The DCVT setpoints for the relays are still accessible from the front panel just as they were on the CVT. 

Dimensions:

Can you fit a square peg in a round hole? For panel mounted gauges, it’s not as difficult as it sounds. If your CVT was panel mounted, you will likely choose to fabricate a new panel or an adapter panel. If you had the gauge resting on a tabletop, it won’t be an issue.

Output Signal / Communication:

The DCVT offers the exact same nonlinear 0-1vdc output curve that was standard on the CVT. In addition, the DCVT offers optional output signals of 0-1vdc linear, 0-5vdc linear, 0-10vdc linear, 4-20mA linear, and 0-20 mA linear.

The DCVT also provides RS232 communication. A certified LabVIEW driver is available.

Terminal Strip Comparison:

The terminal strips look different, but all CVT connections are available on the DCVT. It also gives you the choice of AC input power or DC input power.

Common Applications:

Common Applications for the DCVT (and obsolete CVT) include Vacuum Metallurgy, Vacuum Coating, Vacuum Furnace, Refrigeration (HVAC), Freeze Drying, Lighting Manufacturing, Power/Transformer Maintenance, Cryogenic/Vacuum Insulation, and more.

To learn more about the Teledyne Hastings Instruments Model DCVT Vacuum Controller, visit https://www.teledyne-hi.com/en-us/What-we-do_/Documents/Bulletins/PB-182_Digital%20CVT%20%26%20VT.pdf

If you have questions about vacuum gauges or vacuum controllers, feel free to contact us by phone (+1-757-723-6531 or 1-800-950-2468), email Hastings_Instruments@Teledyne.com, or via Live Chat on our website www.teledyne-hi.com.

Thermal Mass Flow Controllers (MFCs) control the mass flow (or more specifically molecular flow) of gases. If we are measuring flow rates, why are there so may pressure specifications? This blog will attempt to explain the various pressure specifications associated with MFCs.

Standard Temperature and Pressure (or STP):

The volume of a gas changes with temperature and pressure changes; therefore, basic volumetric flow units are almost useless when defining gas flow rates. When you pick up an MFC or look at the calibration report, you always find a value for Standard Temperature and Pressure (or STP. For most MFC applications, it will be listed as STP: 0° C & 760 Torr. This does not mean that the MFC must be used at that temperature and pressure. Some gases may not even be in gas phase at those conditions. STP is a way of defining molar volumetric units. STP allows your gas calculations to be correct when you measure all your experimental data using the same STP values.

Maximum Allowable Working Pressure:

The Maximum Allowable Working Pressure (sometimes expressed as M.A.W.P.) represents the maximum working pressure for which the end user is permitted to operate the MFC. There should be a label on the MFC that defines this value. For safety purposes, the end user should never exceed this limit.

Proof Pressure:

The Proof Pressure is the pressure value to which the MFC manufacturer proof tests the unit. This value is typically 1.5 times the Maximum Allowable Working Pressure. For example: if the Maximum Allowable Working Pressure is 500 PSIG, the manufacture may Proof Test the unit to 750 PSIG. Even though the manufacturer tests the unit to this value, the end user is still not permitted to exceed the Maximum Allowable Working Pressure.

Burst Pressure:

Burst Pressure is the maximum pressure that can possibly be applied to the MFC without physical damage to the pressure containment. It’s typically much higher than the Proof Pressure. MFC manufacturers will define this during product development. This can be modelled using 3D stress analysis and eventually tested using a hydraulic pump. Burst Pressure testing tends to be a favorite for most engineers.

Inlet Pressure & Outlet Pressure:

Some people forget that the MFC contains a proportional control valve. To proportionally control the flow, there must be a pressure drop across the MFC. Inlet Pressure (Up Stream Pressure) is the pressure measured exactly at the MFC inlet fitting. Outlet Pressure (Down Stream Pressure) is the pressure measured exactly at the MFC outlet fitting. To facilitate flow, Inlet Pressure must always be greater than Outlet Pressure. Some MFC manufacturers will define these values on the MFC Serial Number label.

Differential Pressure

Differential Pressure is often abbreviated as dP or ΔP.

dP = Inlet Pressure – Outlet Pressure

Pressure Coefficients:

Even though thermal mass flow values are independent of temperature and pressure changes, the thermal mass flow sensor performance is impacted at higher pressures. The flow sensor consists of a small 316SS capillary tube that is wrapped with several windings of heater wire. When the pressure increases, the capillary tube expands. When that occurs, the heater windings expand with the tube. The error associated with this expansion is represented by the Pressure Coefficient. For example, a typical Pressure Coefficient could be +0.0067%/psi. 

To learn more about the Teledyne Hastings Instruments mass flow meters and mass flow controllers, visit https://www.teledyne-hi.com/en-us/what-we-do/thermal-mass-flow 

If you have questions about mass flow controllers, feel free to contact us by phone (+1-757-723-6531 or 1-800-950-2468), email Hastings_Instruments@Teledyne.com, or via Live Chat on our website www.teledyne-hi.com.

We are starting a new blog series where we will introduce you to our authorized service partners. These partners are fully authorized to calibrate and repair Teledyne Hastings Instruments products.

Our first blog in this series will focus on the EMEA (Europe-Middle East-Africa) Service Center, Chell Instruments. Chell is based in North Walsham, England which is on the east coast near Norwich, about a 3-hour drive northeast of London.

Chell Instruments was established in May of 1976 by Ron and Judith Michell, hence the name Chell. They became a distributor for Teledyne Hastings Instruments shortly after in 1977 and began to distribute Hastings’ vacuum gauges, mass flow meters, and mass flow controllers in the United Kingdom and Ireland. Not only is Chell a great distributor, but they also excel at designing and manufacturing their own products and systems. In fact, they have a full engineering team that allows them to provide turnkey system solutions for their customers.

The last component to Chell’s success (and the topic of this blog) is their extensive calibration lab. Chell operates a complete calibration and repair lab capable of servicing instruments that measure Flow (Gas), Vacuum, Pressure, Temperature, and Electrical properties. Chell’s lab is UKAS accredited (fully accredited to ISO/IEC17025:2017). Chell can calibrate and repair nearly all Teledyne Hastings Instruments vacuum gauges, mass flow meters, and mass flow controllers. They also stock spare parts in England to quickly support most mass flow meter and mass flow controller repairs.

CALIBRATION Capabilities:
Flow (Gas):         0.0010 L/min to 1250 L/min (up to 7 bar); Up to 12,500 L/min (at low pressure)
Vacuum:              1x10^-4 Pa / 1x10^-6 mbar / 7.5x10^-7 Torr to 1000 Torr

Complete details can be found at: https://chell.co.uk/calibration

One of the great attributes of Chell is their flexibility. If you have too many instruments to ship to Chell, they will come to you! They offer on-site calibration services for several ranges of instruments, and they offer this service for most of the United Kingdom. Would you like to calibrate your own vacuum gauges? If so, Chell sells a portable vacuum calibration system called the CalCube. Would you like to calibrate your own mass flow meters and mass flow controllers? If so, Chell sells flow calibration standards (Fluke Molbox/Molbloc) and can even manufacture complete flow calibration systems.

For more details about services offered by Chell Instruments, please visit: https://chell.co.uk

Also, be sure to follow Chell on LinkedIn to stay on top of what’s new. Next year will mark Chell’s 50th anniversary, so stay tuned for their big celebration!
https://www.linkedin.com/company/chell-instruments

For more information on calibration services for vacuum gauges, vacuum transducers, mass flow meters, and mass flow controllers provided by Teledyne Hastings Instruments, please check out: https://www.teledyne-hi.com/en-us/what-we-do/calibration-repair

Time for another blog in our “Employee Spotlight Series.” This time we will meet Rob Milversted. Rob has worked for Teledyne for over 20 years, and he is the Director of Sales for Process Instruments and Systems (Teledyne Hastings Instruments and Teledyne Analytical Instruments).

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

Tell us a little about your background.

I’m a SoCal boy. I’ve lived most of my life in Chino. I attended Cal Poly Pomona and studied Electrical Engineering as an undergrad. I was always shocking myself with things around the house a as kid, so Electrical Engineering just seemed right.

Tell us about your start at Teledyne.

I got a job as an Electrical Engineering Intern at Teledyne Analytical Instruments (TAI) while still in college. In 2002, I was able to join Teledyne full time as an Electrical Engineer. Teledyne allowed me to complete my MBA (also at Cal Poly) while working. I shifted to sales and held multiple sales and sales management positions. In 2021, I was promoted to Director of Worldwide Sales for Teledyne Analytical Instruments and Teledyne Monitor Labs. In 2023, I became Director of Sales for Process Instruments and Systems (Teledyne Hastings Instruments and Teledyne Analytical Instruments).

What is your current role at Teledyne?

As Director of Sales, I have global product sales responsibility for TAI and THI products. I oversee Regional Sales Managers in North America, and I share sales responsibility with our Directors of Sales in APAC and EMEA.

Outside of work, what do you like to do?

I spend lots of time getting my three kids to extracurricular activities. There’s not much free time. My family is heavily involved in Girl Scouts and Boy Scouts. We do a lot of camping. I also enjoy catching NFL games when I can.

What is your favorite thing about working at Teledyne?

The best thing about Teledyne are the people that work here. Everyone I know works extremely hard and wants to help customers. Everyone is like family. I now meet coworkers from other parts of Teledyne, and I wish I’d met them sooner.

Check out more from our blog and read more about our vacuum gauges and mass flow meters and mass flow controllers (and be on the look out for future postings about Teledyne Hastings' employees.) 

The use of Liquefied N₂ (LN₂) has revolutionized aluminum extrusion mold performance. CVS Corporation based in Gimpo, South Korea has developed a proprietary LN₂ cooling process that allows production output to more than double for some extrusion profiles. Production times vary based on the geometry of the extrusion profile. Ram speed test data can be found in Figure 1 below.

Figure 1: Extrusion Profile Table

The Aluminum Extrusion Mold Liquid Nitrogen Cooling System from CVS is designed to control the temperature of both the profile and the mold during the extrusion process. As the billet passes through the extrusion mold, the friction between the billet and the mold creates excess heat. This excess heat limits the extrusion ram speed and is the main cause of reduced productivity in the extrusion process. The CVS process maintains optimum profile and mold temperatures by using automated cryogenic proportional control valves to provide precision dosage of Liquefied N₂.

Figure 2: Aluminum Extrusion Mold Liquid Nitrogen Cooling System from CVS

Mr. Ko Hwa-Jin is the President of CVS Corporation and can be reached by email or website: www.ln2doser.com

Mr. Yoonk Min is the President of Inforad Corp. which is the distributor for Teledyne Hastings Instruments for South Korea. Mr. Min can be reached by email or website: www.inforad.co.kr

Wayne Lewey is the International Sales Manager at Teledyne Hastings Instruments and can be reached by email. 

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