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RS Hydro > Flow Meters > Ultrasonic

Ultrasonic Flowmeters

RS Hydro offer an extensive range of ultrasonic flow meters for sale and rental. The use of non-invasive, ultrasonic flow measurement offers great benefits in many applications. With the use of ultrasonic transducers clamped to the outside of pipework, there is no downtime or disruption of flow. RS Hydro also offer installation, maintenance, calibration and consulting services.

RS Hydro supply the very latest portable ultrasonic liquid flow meter technology, which can measure liquids up to 250ºC , can be used with most pipe materials and linings and on pipes from 10mm to 7000mm diameter. Minimal installation, low cost and no pressure loss make portable ultrasonic flow measurement the best choice for many applications.

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Fixed installation ultrasonic flowmeters with clamp-on, spool piece or wetted transducers.
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Designed for hazardous environments our intriniscally safe and explosion proof flow meters are extremely rugged and can be used for measuring almost any liquid.

The non-contact ultrasonic flow meter is a non-invasive flow meter available in two formats: transit time and doppler. Both technologies feature clamp on designs with transducer arrangements that can detect in-situ flowrates from outside the pipework, without any interruption to flow or process. Transit time flow meters, or also known as 'time of flight' meters are mainly consigned to the measurement of clean liquids, although many flow measurement devices have a maximum tolerance of 5% solids. The principle behind this type of non-intrusive clamp-on (strap on) flow meter is that accoustic waves with a frequency of >20kHz are emitted from one transducer to the other side of the pipe back to the opposite transducer requires less time than when travelling in the opposite direction. The differential transit time of the synchronised signals is proportional to the flow rate of the fluid.

Which Ultrasonic Flowmeter ?

Before purchasing or hiring an ultrasonic flowmeter it's vital that you ensure that the equipment is suitable for your particular application. The table below gives a comparison of four ultrasonic flowmeters.

Mouse over scores for more information

 PT878 PORTAFLOW FLEXIM POLYSONICS
First Impression
Parameters
Portability
Ease of Use
Battery Life
Confidence Feeling
Traceability
Diagnostic Abilities
Range of Uses 9/10 5/10 9/10 6/10
Application Power 9/10 4/10 9/10 6/10
Robustness 9/10 7/10 7/10 7/10
Cost 6/10 9/10 7/10 8/10
Reliability 9/10 5/10 8/10 6/10
20mm Cold Water Copper 10/10 10/10 10/10 10/10
100mm Cold Water 10/10 10/10 10/10 10/10
300mm Wastewater Application 10/10 3/10 10/10 8/10
300mm How Water 9/10 0/10 9/10 2/10
600mm Ductile Iron Water 15 degrees C 200 l/sec 10/10 6/10 10/10 4/10
1500mm Cast Iron 9/10 2/10 9/10 4/10
1500mm Hydro-Turbine Application 8/10 0/10 8/10 3/10
Energy Meter 10/10 5/10 7/10 5/10
Data Logging 10/10 6/10 7/10 6/10
Signal Outputs 8/10 8/10 8/10 6/10
Accessories (ie UTG) 8/10 4/10 8/10 2/10
Accuracy 8/10 8/10 8/10 8/10

GE Panametrics PT878

The GE Panametrics PT868 and PT878 flow meters are designed to withstand rugged use in industrial applications. With superior diagnostics, functionality and accuracy this flow meter is regarded as leading edge technology. The PT878 utilises an acoustic signal-coding technique to make accurate measurements in flows containing gas bubbles or entrained solids. We would recommend this flow meter to professionals who want the most from a portable ultrasonic flow meter. This meter has two external inputs which makes it ideal for a heat metering survey.

Micronics Portaflow 300

The Micronics Portaflow 300 clamp on flow meter is aimed at those who want a compromise between performance and price. This portable flow meter is designed to be used by anyone who has not used a non-invasive flow meter before. With up to 24 hours battery life this flow meter does last longer than any other. However, this flow meter does not accept external outputs eg for heat metering purposes or pump testing.

Flexim

The Flexim ultrasonic liquid flow meter is regarded as a good clamp on flow meter offering the ability to measure two flows with one transmitter and external inputs. However, this flow meter does lack the display and diagnostics facilities of the GE Panametrics PT878.

Advantages of Clamp-On Flowmeters

GE Panametrics PT878GC Portable Ultrasonic Gas Flow Meter

Comparison of Ultrasonic vs Other Types of Meter

Type of Meter Advantages
Coriolis Able to measure flow in medium and large pipe sizes
Vortex less intrusive
low flow capability
Magnetic can measure gas, steam & non-conductive liquids
DP less intrusive little or no pressure drop less need for recalibration
Turbine less intrusive; not subject to wear - no moving parts

Applications for Ultrasonic Flow monitoring

Portable ultrasonic flow meters can measure almost all light homogeneous fluids including water, wastewater (<5% solids) and hydrocarbons. The basic requirement is that the fluid can conduct ultrasound and have an acceptable axis-symmetrical flow. Click here to see the many fluids that ultrasonic devices can measure.

Typical applications include:

Flowmeter Specifications

Although specifications are different between the various manufacturers, the following is intended as a guideline to their performance and specification.

Flow Range 0.01-20m/sec (Bi-Directional)
Accuracy ±0.5-3% of reading
Repeatability Typically ±0.5%
Pipe Size 12.7-7600mm
Operating Temperature
Transducers -40°C to +200°C
Transmitter -10°C to 50°C
Datalogging Typically>100,000 data points, time stamped
Output 4-20mA, pulse
Power Built-in battery with external 12v input, 8-36 hours operation
Dimensions Typically 250 x 150 x 40mm
Weight (Control Unit) Typically 3-5lbs (1-2kg)

Portable Flow Meters : Technical Notes

For optimum accuracy the following conditions must apply:

Requirement
Location At least 10 diameters of straight-length pipework must exist upstream of the measurement point, and 5D downstream. Ideally these distances should be as large as possible.
Wall Thickness For optimum accuracy, the pipe wall thickness should also be measured. Some meters are supplied with ultrasonic wall thickness gauge
Liquid Medium It is essential that the type of fluid is known. Also that there are no air bubbles and that the solid content does not exceed 5%.
Pipe Condition The pipe wall exterior should be free from dirt, paint or corrosion. For optimum accuracy the interior wall should also be free from deposits or corrosion.