What is the difference between laminar flow and turbulent flow?
Thermal flow instruments behave best using a laminar flow, at least if we look at the thermal mass flow meters and controllers with a bypass sensor. To conduct a precise measurement with this flow instrument, laminar flow is preferred.
Beamex Users Group 3rd Annual Meeting in Sydney, NSW
AMS have booked the venue for the 2020 Beamex Users Group. There has been such a positive response from Beamex customers over the last two BUG meetings that we are expecting a large number of people from many industries around Australia.
The meeting will be held over two days and is free for people to attend. With a number of recent and pending product releases, the User Group will allow attendees to familiarise themselves with the Beamex product range and discuss strategies to improve management of your calibration workload. AMS is excited to have this opportunity to work with our customers to build upon their existing Beamex user experience.
Portable Flowmeter Helps Swiss Water Company Reach Peak Performance
Water supply companies are required to monitor and maintain extensive pipeline networks covering a large geographical area. Access to pipework is often limited, suitable measurement points are often remote and are rarely equipped with a power supply. In these cases, a portable flowmeter that is both weatherproof and has its own power supply is ideal. This was the situation faced by engineers working in the town of Wädenswil (Switzerland) where they were conducting pipe and flow surveys as part of a network modernisation project. This was made difficult because of access and local weather conditions which meant finding the right product for the job was very important.
Katronic and more specifically our Swiss distributor, Rolf Muri AG supplied the customer with a measurement system that allowed flow data to be collected over an extended period of time. This was needed in order to provide more accurate information and help the service engineers to form conclusions about the correct dimensioning of the pipeline network. What was of particular interest were the levels of water consumption at peak times as it was hoped that a narrowing of the pipe cross-section would lead to a more consistent flushing of the pipes. It was also hoped that water losses of about one liter/second could be eliminated through the programme of pipe network modernisation.
Do you know why Mass Flow reference conditions matter
ou would think that measurements of mass flow would be expressed in units of mass, such as grams/hour, milligrams/second etc. Most users, however, think and work in units of volume. That’s OK, at least when we are talking about the same reference conditons. Let me start with an example:
Mass versus Volume
Imagine you have a cylinder of 1 liter, which is closed by means of a moveable piston of negligible weight. This cylinder contains 1 liter of air at ambient pressure, approximately 1 bar. The weight of this volume of air at 0°C is 1.293 g, this is the mass.
When we move the piston half way to the bottom of the cylinder, then the contained volume of air is only ½ liter, the pressure is approximately 2 bar, but the mass hasn’t been changed, 1.293 g; nothing has been added, or left out.
STRAIN GAUGES 101
A strain gauge is a sensor that varies its resistance as it’s stretched or compressed. When stress or compression is applied, the strain gauge converts force, pressure, tension, and weight into a change that can then be measured in the electrical resistance.
At the heart and soul of every load cell is a strain gauge. This is the pinnacle technology that allows engineers to collect and analyze force data. In the industry, it is known as force measurement.
Strain gauges are made through a photo-etch process using a flexible backing and a very thin foil. The way a strain gauge works is when the backing and foil stretches or compresses, resistance goes up and down respectively. We know this as force. Think of stretching like a three-lane highway switching to two lanes, and vice versa for compression with two lanes going into three. As the load cell’s internal strain gauge experiences force, it sends a signal with a precise measurement of the amount of force it’s experiencing.
Wet Gas Flow measurement from FCI
Moist or wet gases present a measurement challenge for all gas flow meter technologies. In many applications it is condensation droplets which impact the flow meter’s accuracy and repeatability, rather than entrained moisture. While best engineering practice would recommend removing the moisture from the gas using gas dryers, knock-out pots, or heat wrapping the pipe, those are not always feasible or only partially effective. Moisture, and condensation droplets, can be in the flow steam moving with the gas flow or can also be experienced in the form of rain coming down in an open, vertical stack, in which case the rain is traveling in the opposite direction of the gas flow. Common moist gas applications, and often condensation droplets are found in biogas recovery (WWTP digesters, landfill gas, biogas production systems) and reactors, while rain droplets found in open vertical stacks and flues are common in power plants, oil and gas operations, chemical plants and refineries.
For many years, FCI’s constant power technology has been the proven and preferred thermal mass flow meter solution for gas flow measurement in moist gases. Now, FCI’s new, innovative “wet gas” sensor delivers accurate, repeatable gas flow measurement in the presence of even more moisture and condensation droplets. Available with the Model ST80, this new “WG” sensor can be applied for use in entrained moisture and rain-shielding applications.
To learn more and see recommended installation techniques, specifications, and how to specify, please download our informative new “Best Practices in Moist and Wet Gas Flow” white paper today.
About Positive Displacement Flow Meters
Positive displacement flow meters measure the volumetric flow rate of a moving fluid or gas by way of precision-fitted gears or rotors containing cavities through which precisely known volumes of fluid pass. A basic analogy would be holding a bucket below a tap, filling it to a set level, then quickly replacing it with another bucket and timing the rate at which the buckets are filled (or the total number of buckets for the “totalised” flow).
Positive displacement flow meters are very accurate and have high turndown. They work best with clean, non-corrosive, and non-erosive liquids and gases, although some models will tolerate some impurities. They require no straight runs of pipe for fluid flow stream conditioning though pressure drop can be an issue. They are widely used in custody transfer and are applied on residential home natural gas and water metering.
Constant Power/Constant Temperature Technology
With thermal mass gas flow meters, there have always been two measuring techniques, constant power (CP) and constant temperature (CT). Both of the techniques are viable, popular, and have both advantages and disadvantages. Historically the trade-offs were about range, response times, sensor life, and susceptibility to moisture in the gas and power consumption. Over time, all the reputable manufacturers continuously tried to improve their products to overcome some aspect of their preferred technique’s short-comings.
But what if you just combined both techniques in the same flow meter, and made it field changeable. Should than the actual installation conditions not be as expected? Wouldn’t that be the ultimate solution? Today, this “both” techniques is a reality in Fluid Components International’s new ST80 thermal flow meters. The ST80s incorporate both FCI’s patent-pending AST™ technology (Adaptive Sensing Technology), which is a hybrid drive that combines both CT and CP together, and CP mode. AST utilises fast responding CT technique at lower flow ranges and seamlessly, and automatically, shifts into CP mode at higher flow rates. This AST hybrid technique then provides a faster response, wider flow range and low power consumption in the same flow meter. And, if the application contains any moisture or where the AST response time is too fast, the ST80 can be set to run in the better application matched CP mode only.
So, if you are specifying, designing or using thermal flow meters, you no longer need to make product selection. Trade-offs based on the measuring technique with ST80 are no longer an issue. Further, if your actual application and installation could be different than expected, with the ST80 you can change the measuring technique between AST and CP modes in the field, to adapt to your discovered, actual installed conditions.
KING-GAGE Advanced Non-Contact Tank Level Measurement
KING-GAGE® LevelWAV radar level transmitter provides continuous measurement suitable over a broad range of temperatures, pressures and density variations in liquid storage or processing tanks. This radar transmitter can be used in process conditions exhibiting visible vapors, foam and/or surface agitation. Non-contact measurement is possible for highly corrosive materials (caustics, acids, solvents) and slurries.
KING-GAGE LevelWAV utilizes advanced microwave circuitry that automatically adjusts transmit energy and receiver gain to detect only the reflection from the media surface. 2-wire technology is easy to install and simplifies wiring requirements at the tank. Accurate and reliable operation with no moving parts or product contact eliminates maintenance requirements of other level technologies.
Compact size and mounting footprint makes tank top installation of the LevelWAV radar transmitter suitable for even tight spaces. Radar level measurement is a practical solution in retrofit applications to replace failing or erratic level transmitters.
Output from the LevelWAV radar transmitter can be monitored on KING-GAGE indicators and multiple tank displays enabling tank level to be represented as total volume, weight or depth of contents. Each of these display options also provides excitation power (24Vdc) to the transmitter through the signal loop cable.