Showing posts with label ultrasonic flowmeter. Show all posts
Showing posts with label ultrasonic flowmeter. Show all posts

Thursday, December 28, 2017

Measurement and Calibration Principle of FLEXIM's Non-Invasive Ultrasonic Flowmeter

The principle of FLEXIM's ultrasonic flow measurement of liquids and gases relies on the propagation of ultrasonic wave signals into the medium. This measurement method exploits the fact that the transmission speed of an ultrasonic signal depends on the flow velocity of the carrier medium. Similar to a swimmer swimming against the current, an ultrasonic signal moves slower against the flow direction of the medium than when in flow direction.

For the measurement, two ultrasonic pulses are sent through the medium, one in the flow direction, and a second one against it. The transducers are alternatively working as an emitter and a receiver. The transit-time of the ultrasonic signal propagating in the flow direction is shorter than the transit-time of the signal propagating against the flow direction. A transit-time difference, Δt, can thus be measured and allows the determination of the average flow velocity based on the propagation path of the ultrasonic signals. An additional profile correction is performed by our proprietary algorithms, to obtain an exceptional accuracy on the average flow velocity on the cross-section of the pipe - which is proportional to the volume flow, and when temperature and pressure compensated, to the mass flow.

Since ultrasounds propagate in solids, the transducers can be mounted onto the pipe. The measurement is therefore non-invasive, and thus no cutting or welding of pipes is required for the installation of the transducers.

For more information about FLEXIM, contact Flow-Tech at 410-666-3200 or visit

Sunday, April 30, 2017

Understanding Ultrasonic Flow Measurement

externally mounted flow meters
Externally mounted (clamp-on) flow meters (Flexim)
Ultrasonic flow meters measure, via sound waves inaudible to humans, the velocity of fluid flowing through a conduit. The conduit can be a recognizable closed piping run, or open channels, flumes, or chutes. The technology is predominantly applied to liquids and gases.

There are three types of ultrasonic flow meters, differentiated by their means of measurement. An open channel flow meter derives liquid depth by computing geometrical distance, combining it with a velocity measurement and known dimensional properties of a flume or other channel. A Doppler shift flow meter reflects ultrasonic energy off sonically reflective materials and measures the frequency shift between emission and reflection to derive a fluid velocity measurement. The contrapropogating transit-time flow meter, more recognizably, the transmission flow meter. The transmission flow meter has two versions: the in-line and the clamp-on. The in-line configuration is intrusive, with flow meter hardware extending into and exposed to the measured media. A clamp-on style ultrasonic flow meter resides on the outside of the pipe, emitting and receiving the ultrasonic pulses through the pipe wall. These process measurement tools, using ultrasound technology, have the ability to measure fluid velocity and calculate volumetric, mass, and totalized flow. The use of ultrasonic flow measurement is prevalent in the oil and gas, nuclear, wastewater, pharmaceutical, and food and beverage industries. It is also employed in energy management systems as a means to measure energy demand.

ultrasonic flowmeterFor intrusive flow meters, sensors are fitted opposite one another and alternate bouncing ultrasonic signals back and forth in the pipe, in an almost tennis-like format. In an elementary explanation, by increasing the number of sensors, engineers are able to decipher flow proportions through calculations of velocity between sensory transmissions; thereby, the flow volume can be computed.

For externally mounted flow meters, a clamp-on device affixes the flow meter measurement elements to the pipe. One special characteristic of clamp-on flow meters is the ability to transmit ultrasonic signals through piping up to four meters in diameter, making them suitable for application in very large systems such as those found in hydroelectric or wastewater installations. The clamp-on arrangement also facilitates addition of a flow measurement point to an existing system without process interruption.

The technology is pervasive in the processing industries, having its particular niche of applications where it excels. Proper installation is a key element in producing reliable and consistent results. Ultrasonic energy flow technology is used for custody transfer of natural gases and petroleum liquids. Custody transfer usually entails following industry, national, and government standards and regulations. Other popular applications include compressed air system monitoring and energy usage metering.

Ultrasonic flow meters, with no moving parts, are comparatively low maintenance and self-diagnosing. Temperature and pressure measurements are needed to calculate mass flow of gases. When measuring liquid mass flow in pipes, it is generally necessary for the pipe cross section to be media filled in order to obtain reliable results.

Whatever your flow measurement challenge, share it with a process measurement specialist. Combine your process knowledge with their product application expertise to develop effective solutions.

Sunday, March 27, 2016

Campus Metering: Improve the Energy Efficiency of Your Building with Clamp-on Flowmeters

Clamp-on, Ultrasonic Flowmeter
Clamp-on, Ultrasonic Flowmeter
(courtesy of FLEXIM)
Today there are many reasons to focus on energy optimization efforts. Due to rising cost of fossil fuels and environmental concerns, decreasing overall energy consumption, decreasing operational costs, improving HVAC performance, improving building quality and certification rating is becoming increasingly important. Facility Managers are stepping up their efforts to find efficiency and savings related to heating, ventilation and air conditioning systems, including chillers, boilers, and air-handling components. Energy-efficiency is a top priority for institutional and commercial organizations and will continue to grow in importance for the foreseeable future.

Finding new ways to reduce energy consumption in buildings without compromising comfort and indoor air quality is an ongoing challenge. One of the most significant options a facility has is to add BTU energy metering that is able to accurately meter the new performance of upgraded chillers, pumps, and chilled water distribution system.

Superior precision can be achieved by using clamp-on flowmeters with specially matched and paired ultrasonic transducers and temperature probes that control the heating and cooling flows within the building. These devices offer a superior solution with a high degree of reliability and repeatability for both temporary and permanent applications.

The biggest challenge in retro-fitting flowmeters in existing piping structures are the very tight piping typical of chiller plants, existing valves, vents, and pipe bends. Clamp-on ultrasonic flowmeters provide an easy work-around. Since the clamp-on ultrasonic transducers are simply mounted on the outside of the pipeline, plant operation is not affected in any way during retrofitting. The reworking of existing piping systems for flowmeter installation is not required, making the clamp-on flow meters an ideal solution for retrofitting existing facilities.

Designed with temperature compensation to eliminate inaccuracies or drift through deviations, and powerful correction algorithms to compensate for non-ideal pipe conditions, these energy flow meters offer an accuracy of 1% or better on the flow rate. Plus, low flow velocities can be detected reliably and accurately.

The advantages for choosing clamp-on ultrasonic flowmeters for HVAC retrofit are:

  • Reliable, non-invasive recording of thermal energy (BTU) flows
  • Practically wear-free measurement without measurement drift, unaffected by potential coating formations
  • Works independently of the conductivity of the medium
  • Simple set-up of measuring points without any interruption of operation
  • Minimum installation effort
  • Compact measurement system, can also be easily installed on measuring points which are difficult to access

Research demonstrates the addition and/or upgrade of metering existing HVAC systems can offer effective solutions for energy conservation and thermal comfort, with possible energy savings in the range of 30-40%.

For more information on BTU/Campus/Building Metering, contact:

Flow-Tech, Inc.
10940 Beaver Dam Rd
Hunt Valley, MD 21030
Ph: 410-666-3200

Central VA Office
10993 Richardson Rd#13
Ashland, VA 23005
Ph: 804-752-3450