FLEXIM's Disturbance Correction Overcomes Challenging Straight Run Requirements

In the often limited space of industrial process plants, recommended straight-run requirements can be challenging to find. Due to restricted pipework, it's not always possible to carry out the optimum installation as advised, away from valves, bends, and other inline components that could cause excessive and problematic turbulence. Clamp-on flow meters usually require an inlet length of at least ten diameters for accurate measurement. 

Thanks to FLEXIM's disturbance correction, good accuracy is achieved even at non-ideal in-flow conditions reducing the required inlet length from 10 diameters to just two diameters. This innovation means installation happens in even the tightest spaces without process interruption. The disturbance correction is applicable for all path configurations compensating for cross flow. These are reflect-path and cross-path configurations. 

As part of the development, FLEXIM collaborated with the highly respected PTB on a research project focusing on the exact determination of flow profiles and how they influence the measuring accuracy of clamp-on ultrasonic flowmeters. Calibration determined the disturbance corrections implemented in the meter, firstly under undisturbed conditions and then under disturbed conditions. This allowed the disturbance correction to be obtained from the ratio of the two results, and the procedure was repeated for all types of disturbance that require a correction function to be put in place. Following correction, the uncertainty depends on the number of measurement planes installed, the distance to the disturbance, and its character. 

Analyzed by CFD, the effect of different bend radiuses found in industrial piping is included in the uncertainty. The disturbance correction applies to all fluids, no matter their state of aggregation or the diameter of the pipe. And although the disturbance correction is optimized for 90-degree bends and double bends, it also improves the accuracy of other types of disturbances. Because FLEXIM's flow disturbance correction reduces the required inlet length from 10 diameters to just two diameters, accurate measurements are guaranteed, even with non-ideal installation conditions. Maximum flexibility and cost savings are delivered for both planners and users alike.

Classic Controls, Inc.

https://classiccontrols.com

+1 863-644-3642

Flow Measurement in Subsurface Pipes

Ultrasonic flow measurement, properly configured, can be the preferred solution for flow measurement in water and wastewater pipes, especially those in subsurface locations. Demands for increased monitoring of system flow at numerous points throughout a network or system create a need to install flow measurement instrumentation on existing pipes that are unlikely to have built-in accommodations for the needed sensors.

Ultrasonic flow measurement transducers are mounted on the exterior of existing piping and require no pipe cutting or service interuption to install. The rugged transducers are suitable for subsurface installation and provide long term uninterupted operation. Ultrasonic flow measurement functions over a wide range of flow, providing accurate data during normal, peak, and off-peak hours. The data derived from the measurements can also be used for leak detection. Data output from the instrument can be used locally or transferred by a number of methods to remote monitoring stations for system wide analysis.

The video provides some additional application advantages of ultrasonic flow measurement for subsurface pipe applications. Share your flow measurement challenges of all types with process measurement specialists. Leverage your own knowledge and experience with their product application expertise to develop effective solutions.

Flexim Wins Recognition for Innovative Flow Measurement

Flexim F704 Ultrasonic Flow Meter
Image courtesy Flexim Americas

Flow Control Magazine, which targets solutions for fluid movement, measurement and containment, handed out its annual Innovation Awards recently. Among those receiving honorable mention was Flexim Americas Corporation, for the Fluxus Cryo that provides noninvasive measurement of cryogenic fluids. Special design adaptations prevent ice build up on the measurement apparatus that that can plague other technologies.

Ultrasonic flow measurement offers some distinct advantages over other available methods, with high accuracy, no intrusion into the media, and no moving parts. While the award was specifically for a cryogenic application, Flexim ultrasonic flow measurement instruments are available for an extensive array of applications.

For more information, share your flow measurement requirements and challenges with process instrumentation experts, leveraging your own process knowledge and experience with their product application expertise to develop effective solutions.

Magnetic Flow Meters: Principles and Applications

Magnetic flowmeters are well suited for flow measurement

with conductive fluids.

Image courtesy Yokogawa

Fluid process control operations rely on the operator's ability to accurately determine qualities and quantities of liquid or gaseous materials. In terms of appraising and working with fluids (such as liquids, steam, and gases) the flow meter is a staple tool, with the simple goal of expressing the delivery of a subject fluid in a quantified manner. Measurement of media flow velocity can be used, along with other inputs, to determine volumetric or mass flow. The magnetic flow meter, also called a magmeter, is one of several technologies used to measure fluid flow.

In general, magnetic flow meters are sturdy, reliable devices able to withstand hazardous environments while returning accurate measurements to operators of a wide variety of processes. The magnetic flow meter has no moving parts. The operational principle of the device is powered by Faraday’s Law, a fundamental scientific principle stating that a voltage will be induced across any conductor moving at a right angle through a magnetic field, with the voltage being proportional to the velocity of the conductor. The principle allows for an inherently hard-to-measure quality of a substance to be expressed via the magmeter. In a magmeter application, the meter produces the magnetic field referred to in Faraday’s Law. The conductor is the fluid. The actual measurement of a magnetic flow meter is the induced voltage corresponding to fluid velocity. This can be used to determine volumetric flow and mass flow when combined with other measurements.

The magnetic flow meter technology is not impacted by temperature, pressure, or density of the subject fluid. It is however, necessary to fill the entire cross section of the pipe in order to derive useful volumetric flow measurements. Faraday’s Law relies on conductivity, so the fluid being measured has to be electrically conductive. Many hydrocarbons are not sufficiently conductive for a flow measurement using this method, nor are gases. On the other hand, water and aqueous solutions tend to exhibit sufficient conductivity to apply magmeter technology.

Magmeters apply Faraday’s law by using two charged magnetic coils; fluid passes through the magnetic field produced by the coils. A precise measurement of the voltage generated in the fluid will be proportional to fluid velocity. The relationship between voltage and flow is theoretically a linear expression, yet some outside factors may present barriers and complications in the interaction of the instrument with the subject fluid. These complications include a higher amount of voltage in the liquid being processed, and coupling issues between the signal circuit, power source, and/or connective leads of both an inductive and capacitive nature.

In addition to salient factors such as price, accuracy, ease of use, and the size-scale of the flow meter in relation to the fluid system, there are multiple reasons why magmeters are the unit of choice for certain applications. They are resistant to corrosion, and can provide accurate measurement of dirty fluids – making them suitable for wastewater measurement. As mentioned, there are no moving parts in a magmeter, keeping maintenance to a minimum. Power requirements are also low. Instruments are available in a wide range of configurations, sizes, and construction materials to accommodate various process installation requirements.

As with all process measurement instruments, proper selection, configuration, and installation are the real keys to a successful project. Share your flow measurement challenges of all types with a process measurement specialist, combining your own process knowledge and experience with their product application expertise to develop an effective solution.

Flow Measurement - Sometimes the Simple Solution is Best

These variable area flow meters also permit visible
inspection of flowing media
Courtesy ERDCO Engineering Corp.

For process control and commercial or industrial applications, there are numerous methods of flow measurement from which to choose. Technologies range from very simple applications of physical principles to deployment of very specialized electronics and sensors. The available range of accuracy, response, and cost is quite broad, with a general expectation that higher cost will deliver better performance and accuracy.

Making the best instrument selection for a flow measurement application should include an assessment of what the operators really need in order to safely and effectively run the process or perform the task related to the measurement of fluid flow. Installing instrumentation with capabilities far beyond what is required is almost certainly a waste of financial resources, but may also have an unexpected impact on operators. Through the generation of data that, while accurate, does not provide any actionable information about process condition, operators can be misled, similar to the occurrence of a false or nuisance alarm. Some applications call for high accuracy, some do not. Define your informational needs and select instruments that will meet those needs.

There is a large array of applications that can be satisfied with simpler, less costly measurement technology. These devices often employ turbines or vanes to produce an indication of flow rate. Incorporated into some of the instruments is a means to visually observe the flowing liquid to verify color and clarity. Simple devices sometimes are intended only to indicate the presence of fluid flow, and whether the flow rate is high or low. Configurations are available that allow insertion into lines under pressure (hot tap) through a full port ball valve. Other variants with combinations of features and capabilities abound.

The selection range is enormous, so define your minimum needs first, then search for a compatible product. Your search can be enhanced by contacting an instrumentation specialist. Combining your process expertise with their broad product knowledge will produce effective solutions.

Variable Area Flow Meter - SeeFlo from Classic Controls, Inc.

Transit Time Differential Ultrasonic Flow Measurement - How It Works

Ultrasonic flow meter, transducer and control unit
Courtesy Flexim

The measure of flow is a pervasive task in fluid process control. There are several differing technologies employed for measuring fluid flow, each with its own set of performance and application attributes that might make it the advantageous choice for a particular operation.

Ultrasonic flow measurement uses several methods for determining the average velocity of a fluid. One of those methods employs the difference in the transit times of ultrasonic pulses travelling with the flow direction and against the flow direction. The flow velocity of the media will offset the transit times between the flow and counterflow measurements. The measured difference in transit times can be used to determine average flow velocity and, with additional processing, mass flow.

Ultrasonic flow meters are accurate and provide repeatable results, making them suitable for custody transfer operations, as well as many other process control applications. Little maintenance is required and the units have no moving parts. Measurement instruments are available with in-line or clamp-on mounting, providing a high level of installation and application flexibility.

The short video below provides a clear explanation of how transit time difference measurement works. Share your flow measurement challenges and requirements with a product application expert, combining your process knowledge with their product expertise to develop effective solutions.

 

Thermal Flowmeters with Constant Temperature Differential (∆T) Technology to Measure Mass Flow Rate of Air and Gases

Thermal Flow Meter
Sensor
Fox Thermal Instruments

Thermal flow meters use a constant temperature differential (∆T) technology to measure mass flow rate of air and gases. The thermal mass flow sensor consists of two Resistance Temperature Detectors (RTD’s). The sensor elements are constructed of a reference grade platinum wire wound around ceramic mandrels that are inserted into stainless steel or Hastelloy tubes.

The reference RTD measures the gas temperature. The instrument electronics
heat the mass flow sensor, or heated element, to a constant temperature and measures the cooling effect of the gas flow. The electrical power required to maintain a constant temperature differential is directly proportional to the gas mass flow rate. The microprocessor then linearizes this signal to deliver a linear 4 to 20mA signal.

One manufacturer, Fox Thermal Instruments, implements a

technology they call the Power Pro™ Sensor. Their sensor operates at a higher power level than other competitive thermal technologies, providing better response time and wider turndown. When compared to a typical differential pressure type flow meter, as shown to the right, the Power Pro™ Sensor offers better low flow or low end sensitivity. The Power Pro™ Sensor also provides exceptional accuracy at high velocities - up to 50,000 SFPM air.

The Fox DDC-Sensor™ is a new state of the art sensor technology used in the Fox Model FT1 Thermal Gas Flow Meter. The DDC-Sensor™, a direct digitally controlled sensor that is interfaced directly to the FT1 microprocessor for more speed and programmability.

Like the Power Pro™ Sensor, the DDC-Sensor™ accurately responds to changes in process variables (gas flow rate, pressure, and temperature) which are used by the microprocessor to determine mass flow rate, totalized flow, and temperature.

In addition to measuring flow, the DDC-Sensor™ provides a technology platform for calculating accurate gas correlations. The FT1 correlation algorithms allow the meter to be calibrated on a single gas in the factory while providing the user the ability to select other gases in the Gas-SelectX® gas menu. Fox’s Model FT1 with its DDC-Sensor™ and state-of-the-art correlation algorithms provide an accurate, multi-gas capable thermal flow meter for gas applications.

Thermal Mass Flowmeter and Temperature Transmitter from Classic Controls, Inc.

Accurate Measurement of Low Flow In Compressed Air Systems

Air compressors can incur significant operating costs.
Minimizing system leaks reaps savings.

Plant operators are well aware of the cost associated with continuous delivery of  compressed air, a useful medium utilized as an energy source. Large or multiple compressors consume considerable amounts of electric power maintaining system pressure and flow requirements. With extensive piping and countless fittings, there are many potential points of leakage. Scheduling of various production operations can vary the demand for compressed air significantly. Getting control of your compressed air system and reducing operating cost is a noble goal. One of the primary tools needed to manage energy costs will be accurate and reliable flow measurement equipment. Here are some characteristics of flow measurement instrumentation that should prove advantageous:

Portable Ultrasonic Flow Measurement Instrument
Flexim

• Non-invasive measurement from the outer pipe wall that does not add potential leak sources or pressure drop.
• Availability in fixed or portable configuration.
• Highly accurate, with paired temperature compensated traceable calibrated transducers
• Installed without disturbance to piping.
• Bidirectional measurement
• Rugged instrument design suitable for any kind of industrial environment

Ultrasonic flow measurement technology can provide all of these characteristics, providing
information that enables the operator to make fact based decisions about system design, management, and maintenance. Learn more about how ultrasonic flow meters specifically configured for compressed air system application can help you start reducing your operating cost and developing a higher level of control over your compressed air system. Share your process challenges with a product specialist and work together to build the best solution.

Portable flow meter for measurement of compressed air, gases, and heat quantitites from Classic Controls, Inc.