Ultrasonic flow measuring devices from Endress+Hauser offer practical, reliable monitoring of liquid flow rates with high accuracy and very few process limitations.
A new generation ultrasound flowmeter from Endress+Hauser is reinventing standards with its uncomplicated installation, quick-set-up software and wide application range, all of which contribute to facilitating a low-cost installation that does not interrupt the process. The sophisticated electronics provides accurate results - even for the most complex applications.
These ultrasonic flowmeters fall under the process instrumentation and control specialist's PROline family of complete flow solutions. All PROline instruments, regardless of measurement principle, function off the same software platform - for commonality in operation and interchangeability of internals. This also offers optimum support for users, from planning and initial operations to configuration, diagnostic procedures and maintenance. PROline has now added a new ultrasonic flowmeter to the Endress+Hauser programme, the PROline Prosonic Flow that is easy and practical to install. The two system sensors attach to the exterior wall of pipes and flow rates are determined by the run-time difference method.
High-performance electronics processes the measured values, taking into account relevant application data such as the nominal diameter, thickness of the wall and lining material, to accurately calculate the volume flow. The same system may be used for pipes made of different materials and with diameters up to 4000 mm, a fact that greatly facilitates warehouse logistics.
The electronics component also supports initial operations handled by the user - all-important application parameters are first entered into synoptically arranged menus. The user then receives highly detailed and easy-to-follow instructions to assure trouble-free mounting. A labelled, pre-punched mounting rail provides exact sensor positioning whilst a tongue-and-groove combination guarantees consistently correct insertion of the sensors into the sensor holders. The fixing part of this mounting kit is equally suitable for strapping bands as for direct, weld-on solutions. IP68 stainless steel sensors and coated-aluminium IP67 transmitter housings maintain operational integrity under a broad scope of conditions.
The individual stainless steel-constructed elements are resistant to humidity, corrosion and pollution (they won the prestigious Vaaler award (USA) on the basis of their elegant design) - so that the Prosonic Flow may be used under the worst ambient conditions. For maximum accuracy under fluctuating temperature, the precise positioning of the instrument is maintained by temperature-compensated sensor holders.
The standard wall-mounted housing or the field housing for process applications incorporates either pushbutton or touch-control operation as well as Endress+Hauser's quick set-up menu for optimal ease of commissioning. Integration into a superset automation is easy to realise - the Prosonic Flow is compatible with all common process control systems, such as 4 to 20 mA, Profibus PA/DP and Foundation Fieldbus. Electronics and sensors are available in hazardous area versions and, therefore, suitable for ambient temperatures between -40 and +170°C. Prosonic Flow is fully certified according to FM/CSA regulations with the process version carrying ATEX approval for hazardous areas.
Case studies
A water-supply system for approximately 18 million people was split into two operators. To be able to settle costs and revenues separately, the pipes had to be retrofitted with flowmeters. Shutting down the entire water supply, which provides 30 000 l/s, was clearly not an option. Thus, a series of Endress+Hauser's Prosonic Flow instruments were mounted onto the outer wall of cement-lined steel pipes 1000-3000 mm in diameter. No modifications of the pipework were required, construction measures were unnecessary, and the water supply remained uninterrupted.
The same benefits were applied to an automobile factory: production did not have to be interrupted to install the flowmeters, and the very same type of sensor could be mounted on pipes with nominal diameters of DN 80 to DN 300. Some of these devices were also put to task as enthalpy counters.
In a waterworks supplying 10 000 m3 of water daily, a test measurement period of several weeks' duration convinced its operators of the advantages of ultrasonic technology and led to their equipping the system with ultrasonic flowmeters at 18 measuring points. The water division within the supply network was to be monitored and optimised if and where necessary. To test a measuring system of this type before ordering was only possible because the pipes did not have to be opened or drilled for installation purposes. In this way, the significant cost of disinfecting and rinsing - essential for long pipes - were avoided. The ultrasonic devices proved their practical worth so rapidly that the operator was moved to equip the outlet of the filter basins in the main waterworks with PROline Prosonic Flow devices as well. Installing electromagnetic flowmeters for such nominal diameters - about 400 DN - would otherwise have been disproportionately expensive.
In the case of a cooling-water pipe to be installed in a power station built in the '50s, measuring points to ascertain flow rates were to be retrofitted. The carbon-steel pipe had a nominal diameter of 9000 mm, an 8,5 mm thick wall and a 3 m thick anti-corrosion asphalt coating.
Endress+Hauser's ultrasonic flowmeter offered a cost-effective alternative requiring neither the pipe nor the building to be modified. Only the asphalt coating had to be removed locally to fit the sensors. Any other measuring system would have required prohibitively expensive remodelling.
Replacing a conventional, defective measuring device is a typical application, given the rather unfavourable conditions at the power station where river and seawater is used for cooling purposes. To avoid a strong increase in temperature in the return flow of both cases, the flow rate was monitored and regulated at two measuring points with the help of electromagnetic flowmeters. When a routine maintenance check revealed that a coil of one of these flowmeters was damaged, the operator opted to replace both devices. However, this would have led to the whole plant being shut down. Neither was it possible to acquire within a reasonable time frame a new electromagnetic flowmeter with nominal widths of 900 and 700 mm. Some reservations existed as to whether using ultrasonic systems was a reasonable solution as the pipes were made of almost noise-proof, fibreglass reinforced pipes. The problem was solved by simply clamping the ultrasonic systems onto the former measuring pipes of the electromagnetic flowmeter. To do this, the measuring pipes were first demantled, the covers and coils of the electromagnetic flowmeter removed and the lining replaced with one made of soft rubber. The entire replacement took only three days to complete.
As pipes do not have to be drilled into or otherwise modified to mount the device, these flowmeters are also well suited to applications subject to safety regulations such as those used by the chemical industry. As the measuring devices are not in direct contact with corrosive or toxic media, no additional approval procedures are required when retrofitting a system or replacing a device. Such cases offer the added advantage of allowing the devices to be mounted during operation, plus brief standard delivery delays of a mere 10 days.
With its PROline Prosonic Flow range of ultrasonic flowmeters, Endress+Hauser brings flow measurement simplicity to many areas in industry.
Endress + Hauser
(011) 262 8000
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