Archive for January 2013

The Value & Versatility of Handheld Ultrasonic Flow Meters

Posted on Monday, 28 January 2013 by

Todays handheld ultrasonic flow meters are engineered to deliver fast, non-intrusive flow and BTU measurement across a broad array of pipe sizes and applications for water, waste water, heating, cooling, and other liquid flow applications.

These new meters are completely portable and rely on clamp-on sensors to effectively perform non- intrusive measurements on flow, temperature and heat energy/BTU consumption on pipes ranging from 0.5” to 120” in diameter. Many of these new products range in size from 12 lbs. to as little as 1lb, but provide large data logging storage, rich analog input/output options and comprehensive on-site diagnostic features. “Smart” capabilities via Bluetooth interface together with companion software can provides onsite connectivity to a smart phone or PC for fast data downloading, and detailed data visualization and analysis.

Many of these new portable flow meters like the one mentioned above use transit-time measurement, where the system utilizes a pair of sensors that function as the ultrasonic transmitter and receiver. The sensors are installed on the pipe wall, either clamped on the outside of the pipe or inserted into the pipe at a predetermined distance from one another. The flow meter operates by alternately transmitting and receiving a coded burst of sound energy between the two sensors and measuring the transit time it takes for sound to travel between the two sensors. The difference in the transit time is directly related to the velocity of the liquid in the pipe. The flow rate is then calculated based on the transit-time difference, the geometry of the pipe and the fluid dynamics formula.

The sensors are commonly mounted with the Z-method or V-method. With the Z-method, the two sensors are installed on opposite sides of a pipe. This method offers a shorter sound path, thus, better signal strength, and is often used for large size pipes where signal strength is critical. With the V-method, the two sensors are installed on the same side of a pipe. The sound path is doubled, thus, the measurement accuracy is better. This method is often used for small and medium size pipes.

Portable flow meters are designed to be so compact that you are able to use one hand to hold and operate the meter. The user interface is usually back-lit and easy to read in dark environments. The unique clamp-on fixture design makes the installation easy without needing specialized tools.

Portable ultrasonic flow meter devices are good choices for flow survey, meter verification, pump checking, HVAC balancing, facility management and other demanding flow monitoring applications where measuring the liquid flow from outside of a pipe is preferred . Examples of other suitable applications include:

  • Water, including hot water, chilled water, city water, sea water and more.
  • Sewage and drainage water with small particle quantity
  • Oil, including crude oil, lubricating oil, diesel oil, fuel oil, etc.
  • Chemicals, including alcohol, acids and more.
  • Solvents
  • Beverage and food processors
  • HVAC hot and cool water, water/glycol solutions
  • Water and waste treatment
  • Power plants (nuclear, thermal & hydropower) heat energy boiler feed water
  • Metallurgy and mining applications (e.g., acid recovery)
  • Marine operation and maintenance
  • Pulp and paper
  • Pipeline leak detection, inspection, tracking and collection
  • Energy measurement and balancing
  • Water distribution network monitoring
  • Energy consumption supervision and water conservation management

This post is shared by spiremt.com, which is a leading supplier of digital flow meters , and water meters. Here you may get the portable ultrasonic flow meter at very affordable price.

The Basics of Liquid Ultrasonic Flow Meters

Posted on Tuesday, 8 January 2013 by

Today's advanced ultrasonic flow meters enable the accurate measurement of liquid flow across a wide variety of process control, water resource management, and energy consumption applications. To select the right ultrasonic flowmeter for your specific liquid application, you must first understand the four basic ways in which ultrasonic flowmeters are classified:

Measurement principle: Transit-time vs. Doppler
Transit-time flowmeters are based on the time difference between upstream and downstream sound propagation intervals, and provide one of the most reliable and time tested measurement principles available to date. This approach provides very good accuracy (±1-2%), and works well for clean flow applications or flow with minor particles. Applications include pure water, sea water, wash water, sewage, process liquids, oils, chemicals, and any homogeneous liquids which are capable of ultrasonic wave propagation.

Doppler flowmeters are based on the Doppler Effect. They work well with suspension flows where particle concentration is above 100ppm and particle size is larger than 100um, but less than 15% in concentration. Doppler is easier to make and less accurate (±5%), thus, it is cheaper than a transit-time flowmeter.

Device Portability: Handheld vs. Wall-mount
Handheld (or portable) flowmeters are effective for flow survey, HVAC, and other applications where mobility is a critical requirement. Some handheld flowmeters can be deployed as long-term measurement solutions when and if the environment is accommodating.

Wall-mount (or fixed installation) flowmeters are more suitable for applications such as process control and long-term continuous flow monitoring. The instrument enclosure is often weather-resistant or explosion-proof. These types of meters are usually cheaper than handheld devices because they are normally ordered in large quantities. 

Transducer installation: Clamp-on vs. Wetted
Clamp-on flowmeters are non-intrusive, easy to install and easy to maintain. The transducers are mounted outside of a pipe, and don’t require the cutting or drilling of the actual pipe. Clamp-on transducers are nonintrusive and therefore cause no pollution or pressure drop in the liquid being measured.

There are two varieties of wetted flowmeters, insertion and flow cell (inline type). Insertion flowmeters require the pipes to be drilled to install the transducers. However, a number of manufacturers provide hot-tapping tools which allows for the transducer installation without depressurizing the pipe or shutting down the flow.

Flow cell, also called spool piece are installed in line with the pipe, through the use of special pipe fittings. The transducers are pre-installed on the flow cell, thus, installation errors are kept to a minimum. In general, wetted transducers provide better accuracy and long-term stability over clamp-on varieties, but usually cost more.

Transducer scheme: Single-path vs. Multi-Path
Single-path flowmeters utilize one pair of transducers to form one ultrasonic path to intercept the flow in a pipe. It is suitable for small and medium size pipes. For larger pipe sizes, shorter straight pipe runs and greater accuracy, multi-path transducer installation is a good option. Multi-path flowmeters are traditionally more expensive than a single-path flowmeters, and are often implemented in applications such as custody transfer where accuracy is of paramount important.

This post is shared by spiremt.com, which is a leading supplier of ultrasonic heat meters, and water meters. Here you may get the portable ultrasonic flow meter at very affordable price.


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