China has a long history of supplying and metering gas, starting with diaphragm meters almost fifty years ago. In more recent times, however, the newer technologies are looking increasingly attractive.
In the 1960s, China began to import foreign technology and a gas meter factory was built to manufacture diaphragm gas meters using the ‘push and pull’ style of valve motion. By the 1970s, gas meters were widely used in China. In some areas pipelines were submerged, and marsh gas and coal gas were the main energy sources.
The 1980s saw the introduction of rotating valve meters by many manufactures, which performed better than the push and pull style. A few manufacturers tried to develop impeller-type gas meters in the 1990s, but this initiative failed. Generally speaking, the main instrument for measuring gas consumption before the end of the last century was the diaphragm gas meter.
DEVELOPMENT OF SMART CARD GAS METERS
In the late 1990s an IC (smart) card gas meter, a long distance transferring diaphragm gas meter and some other new models with electronic measures or electronic communicating signals emerged on the market. Based on the mechanical diaphragm meter, these new models added transducers, control circuits, motor valves, LCD, smart cards and more.
Several problems with IC card gas meters were identified at the research stage, which restricted their development. These were:
• A design deficiency on the control circuit: logical transaction problems caused the system to be unstable.
• Electromagnetic control valves were used almost exclusively, but reliability was a problem.
• The design of IC card gas meters depended to a great extent on imitating technology from abroad, and the main power supply was lithium batteries. However, the service life of lithium batteries is considerably less than many manufacturers indicate.
These problems influenced the newly developed gas meter negatively, and as a consequence they were poorly received by our domestic gas supply company. However, China’s economic development, together with improvement in the IT industry, have increased the market potential for energy, gas and water meters. This encouraged many well-known IC designers and manufacturers to spend a great deal of time and manpower on developing new and more reliable products.
By the turn of the century, three types of IC card gas meters offering reliable quality and stable performance had been introduced – a memory card, with low cost and low security; a logic encryption card, with moderate cost but high security; and a CPU card, at high cost but with highest security. Advanced meters with remote meter reading and credit transfer facilities were also developed, using wireless and wired communication technologies.
ADVANTAGES AND DISADVANTAGES
The mechanical diaphragm gas meter is highly regarded for its stability and reliable measurement, but the data it produces cannot be used for energy management, and the problems of collecting revenue and meter tampering remained. The smartcard gas meter, on the other hand, offers a prepayment function whereby consumers purchase gas before they consume it, thus solving the problem of mailing bills and collecting the money. In addition much more data is available, which benefits both the supply company and the consumer, and the protect function prevents consumers from tampering with the meter.
Today both the diaphragm and the IC card gas meters are widely available in China; over 4 million of the former are in use in the domestic market, with an installed base of over 1 million smartcard meters – up from 500,000 in 2003. When the project to transport natural gas from the west to the east is completed in a few years’ time, we expect to see a huge increase in the number of gas meters installed in the residential sector. This increase will apply to energy and water meters too; China is a developing country, and to encourage conservation of precious resources these three meters are now compulsory in all new buildings.