[China Instrument Network Instrumentation Industry] With the development of new flow sensor technology, electronic water meters will occupy a place. Increasing water metering accuracy, increasing measurement range, and improving small flow measurement characteristics are common requirements for all water meters. Ultrasound is an important development. One of the directions. Some well-known watch companies in Europe began to use batches in some projects. In China, ultrasonic measurement methods have been widely used in heat meters and heat flow meters. Due to the advantages of ultrasonic methods and the continuous development and improvement of ultrasonic measurement circuits, smart water meters will also develop in this direction.
Industry sources believe that the demand for large-caliber ultrasonic meter mainly comes from the replacement of the large-diameter mechanical water meter in use; the demand for small-caliber ultrasonic meter mainly comes from the incremental demand after the implementation of the ladder water price. The bottleneck of promotion is whether the price can be reduced to the current level. The price level of the smart meter used, and the second is whether the technology is mature.
Ultrasonic water meter product standard
International Standard
ISO 4064-2014 Water meters for cold potable water and hot water
The international standards for water meters mainly specify the product performance indicators and test methods.
National standard
GB/T 778-2007 Measurement of water flow in closed full pipes Drinking cold water meter and hot water meter
The national standards of water meters are basically equivalent to international standards and are applicable to all types of water meters.
Industry Standard
CJ/T 224-2012 electronic remote water meter
On the basis of national standards, the technical requirements of remote data interface for water meter data have been supplemented.
CJ/T 133-2012 IC card cold water meter
Based on national standards, the technical requirements of the water meter including cost control devices including control valves and card readers are supplemented.
CJ/T 434-2013 Ultrasonic Water Meter
Based on the product features of ultrasonic water meters, the relevant technical indicators involved in the national standards are enhanced or refined.
Ultrasonic water meter performance characteristics
High precision: typical error within ± 1%, more than 1 times higher than mechanical water meter.
Wide measuring range: The highest measuring range ratio is 400:1, which is 5 times that of mechanical water meters. It can be applied to various water conditions.
Start-up low: The sensitivity is extremely high, and the tiny water flow can be identified, which can effectively improve the benefits for the water supply department.
Small pressure loss: The straight-through metering pipe structure has little effect on water flow and can reduce costs for the water supply department.
No wear: no mechanical wear phenomenon of traditional water meter, the measurement accuracy will not decrease after long-term operation.
Strong protection: product product structure and principle ensure that the water meter can work for a long time under high pressure, low temperature and flooding conditions and will not be damaged.
Anti-tampering: Digital encryption technology prevents users from tampering with internal data and sending alarm messages when the meter is illegally disassembled.
Development Outlook
Measurement performance
The precise measurement of water consumption is the basic requirement of ultrasonic water meter as a measuring instrument. Water meter manufacturers should continue to optimize the product technical route and production technology, continuously improve the measurement performance of ultrasonic water meter, and ensure that the metering performance is not affected by the service life of the product and the quality of water supply. The non-returnable water supply or disputed water supply generated by the water supply department due to metering errors.
Protection ability
Water meters require not only accurate metering but also durability. Ultrasonic water meter structure design should fully consider the product will not work long-term exposure, dust, water, soaking, high temperature, low temperature, high humidity and other weather conditions will not be damaged. In addition, data encryption and redundant backup algorithms should also be used to ensure that the electronic metering data stored inside the ultrasonic meter is not tampered with.
Smart features
At present, the so-called "intelligence" of smart water meters is only simple management functions such as remote data transmission or cost control. Ultrasonic water meters should provide users with intelligent application functions such as water usage statistics, water behavior assessment, and pipeline network status warning based on their digital measurement results, and provide rational advice for water supply units to optimize water supply and save water for users.
Manufacturing cost
Ultrasonic water meter's material cost, key parts cost control and assembly, calibration costs are higher than the mechanical water meter, resulting in higher product prices compared with the traditional smart water meter. The bulk purchase of ultrasonic water meters by the water supply sector cannot bring significant economic benefits to them.
Battery life
Current water meter manufacturers evaluate the battery life according to the rated capacity of the battery and the average operating current of the electronic circuit board. However, the environmental temperature change under actual water meter installation and use conditions and the self-discharge of the battery over a long period of time will cause the battery power to rapidly decay. Large battery water meter replacements due to battery problems can have serious social and economic consequences.
Reliable electronic components
Ultrasonic water meters have problems with the reliability of long-running electronic components in mechanical water meters. Water meter manufacturers must rigorously verify the reliability of ultrasonic sensors, electronic circuit boards, and embedded function software, and break the “electronically non-mechanical-reliable†mentality formula of the water supply department that has long been associated with mechanical water meters.
Applicability of water quality
Theoretically, the metering performance of ultrasonic water meter will not be affected by water quality. However, if there is long-term accumulation of impurities such as sediment in the pipeline, or if the pH of the water is too high, the emission receiving surface of the ultrasonic sensor may be contaminated. And the metal reflection surface of the acoustic wave reflection mechanism blocks the acoustic wave path and makes measurement impossible.
Conclusion
At present, some domestic water meter manufacturers with technical strengths have carried out design and research and development of small-caliber household-type ultrasonic water meters. As a brand-new product, ultrasonic water meters have broad prospects for development in the future.
(Original title: Ultrasonic meter performance and outlook)
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