The six reasons that affect the performance of the mechanical heat meter cause the reliability and durability of the mechanical heat meter are intricate, and there are six main aspects.
First, each heating season heat meter must be continuously operated for 4 to 5 months. During the warming season, the mechanical heat meter is deactivated for 7-8 months. In addition, the working environment of the mechanical heat meter is very complicated, and many of the heating water contains corrosive substances. These objective factors place high demands on the long-term reliability of mechanical heat meters.
Second, the mechanical heat meter is compared with the ordinary water meter. In the average household, an ordinary water meter has a monthly water metering capacity of about 5 cubic meters, and the metering method is intermittent. The meter reading system also counts about 60 cubic meters per year. The continuous flow of uninterrupted hot water through the mechanical heat meter is about 864 cubic meters for a four-month mechanical heat meter in a heating season. In other words, the amount of water metered in a winter in a mechanical heat meter is equivalent to the amount of water metered in a normal water meter for 14 years. It can be seen that the heat supply itself has a long-term reliability requirement for the mechanical heat meter, especially the wear resistance of the mechanical mechanical heat meter bearing material. Therefore, without a strict special design, the use of hot water meters or even cold water meters as the base table of mechanical heat meters, its long-term reliability is difficult to stand the test.
Third, the mechanical heat meter is an important measuring instrument and basis for the settlement of heat metering trade, and it must ensure accurate measurement and long-term reliability. Without long-term durability testing or effective long-term reliability verification, the reliability of mechanical heat meters at high temperatures is difficult to determine by simple high-temperature testing, and the first-time verification and factory inspection of mechanical heat meters cannot guarantee long-term reliable operation. Therefore, in the mechanical heat meter type test or reliability test, the durability of the mechanical heat meter flow sensor should be tested under stricter requirements and test procedure conditions. This makes it possible to ensure stable, reliable and accurate measurement of the long-term operation of the mechanical heat meter. In fact, most of the products on the market of mechanical heat meters have not carried out this basic test at all.
Fourth, it is proved by practice that the instrument product is sampled by the Hualuogeng method in the mechanical heat meter before the factory inspection, and the corresponding high-low temperature and large-flow cross-change alternate simulation operation aging test is carried out. This key production process is used to test the product's working durability. The situation and reduce the failure rate of the product and improve the reliability and durability of the whole work of the instrument product have a multiplier effect. However, the competitive market is cruel, companies have to squeeze costs, it can be said that no company has carried out this more critical basic work. ?
The fifth is the thermal meter used in the market, and a large number of mechanical mechanical heat meters and ultrasonic mechanical heat meters are used. The mechanical mechanical heat meter has a simple structure and low price is the biggest advantage, but in addition to its low measurement accuracy, the rotating impeller is easily caught by solid impurities or scale, so that the mechanical heat meter cannot work normally. This serious defect is likely to affect the reliable operation of the mechanical heat meter.
For ultrasonic mechanical heat meters , although there is no moving parts in the measuring chamber, the clogging problem is not serious, but the ultrasonic mechanical heat meter of the ultrasonic time difference method which is commonly used in the current mechanical heat meter market to reduce the cost, because of The presence of the ultrasonic reflection sheet in the measurement chamber and the signal strength of the low flow rate small signal have to be used to measure the cavity structure using the Venturi diameter reduction. Like the mechanical impeller type mechanical heat meter, when the heat carrier fluid contains large, excessive particles or bubbles and fluids, "flocs" appear, and the measuring chamber wall or the ultrasonic reflector has a fouling layer, the ultrasonic wave The quality and intensity of the signal will be greatly reduced or even the ultrasonic signal will not be reflected, which will affect the accuracy of the measurement and the reliability of the work of the watch. Therefore, water quality also has a great influence on the measurement performance and operational reliability of the ultrasonic mechanical heat meter.
Due to the existence of these fatal quality hazards of the above mechanical heat meter products, they are inherently determined by their basic working principle that they cannot have high long-term reliability and durability. Sixth, the water quality of domestic central heating is special, not only “ The hardness is high, and it is easy to scale at high temperature, and there are various kinds of particulate impurities (such as magnetized particles, iron filings), a small amount of bubbles, and even pollutants such as "flocs". In this relatively special state of centralized hot water supply, the demanding requirements of the meter for the mechanical heat meter product itself, coupled with the existence of inherently fatal quality hazards of some products, the lack of key production processes in the production process, the market of mechanical heat meter products It is not surprising that the current state of durability and reliability is low.
First, each heating season heat meter must be continuously operated for 4 to 5 months. During the warming season, the mechanical heat meter is deactivated for 7-8 months. In addition, the working environment of the mechanical heat meter is very complicated, and many of the heating water contains corrosive substances. These objective factors place high demands on the long-term reliability of mechanical heat meters.
Second, the mechanical heat meter is compared with the ordinary water meter. In the average household, an ordinary water meter has a monthly water metering capacity of about 5 cubic meters, and the metering method is intermittent. The meter reading system also counts about 60 cubic meters per year. The continuous flow of uninterrupted hot water through the mechanical heat meter is about 864 cubic meters for a four-month mechanical heat meter in a heating season. In other words, the amount of water metered in a winter in a mechanical heat meter is equivalent to the amount of water metered in a normal water meter for 14 years. It can be seen that the heat supply itself has a long-term reliability requirement for the mechanical heat meter, especially the wear resistance of the mechanical mechanical heat meter bearing material. Therefore, without a strict special design, the use of hot water meters or even cold water meters as the base table of mechanical heat meters, its long-term reliability is difficult to stand the test.
Third, the mechanical heat meter is an important measuring instrument and basis for the settlement of heat metering trade, and it must ensure accurate measurement and long-term reliability. Without long-term durability testing or effective long-term reliability verification, the reliability of mechanical heat meters at high temperatures is difficult to determine by simple high-temperature testing, and the first-time verification and factory inspection of mechanical heat meters cannot guarantee long-term reliable operation. Therefore, in the mechanical heat meter type test or reliability test, the durability of the mechanical heat meter flow sensor should be tested under stricter requirements and test procedure conditions. This makes it possible to ensure stable, reliable and accurate measurement of the long-term operation of the mechanical heat meter. In fact, most of the products on the market of mechanical heat meters have not carried out this basic test at all.
Fourth, it is proved by practice that the instrument product is sampled by the Hualuogeng method in the mechanical heat meter before the factory inspection, and the corresponding high-low temperature and large-flow cross-change alternate simulation operation aging test is carried out. This key production process is used to test the product's working durability. The situation and reduce the failure rate of the product and improve the reliability and durability of the whole work of the instrument product have a multiplier effect. However, the competitive market is cruel, companies have to squeeze costs, it can be said that no company has carried out this more critical basic work. ?
The fifth is the thermal meter used in the market, and a large number of mechanical mechanical heat meters and ultrasonic mechanical heat meters are used. The mechanical mechanical heat meter has a simple structure and low price is the biggest advantage, but in addition to its low measurement accuracy, the rotating impeller is easily caught by solid impurities or scale, so that the mechanical heat meter cannot work normally. This serious defect is likely to affect the reliable operation of the mechanical heat meter.
For ultrasonic mechanical heat meters , although there is no moving parts in the measuring chamber, the clogging problem is not serious, but the ultrasonic mechanical heat meter of the ultrasonic time difference method which is commonly used in the current mechanical heat meter market to reduce the cost, because of The presence of the ultrasonic reflection sheet in the measurement chamber and the signal strength of the low flow rate small signal have to be used to measure the cavity structure using the Venturi diameter reduction. Like the mechanical impeller type mechanical heat meter, when the heat carrier fluid contains large, excessive particles or bubbles and fluids, "flocs" appear, and the measuring chamber wall or the ultrasonic reflector has a fouling layer, the ultrasonic wave The quality and intensity of the signal will be greatly reduced or even the ultrasonic signal will not be reflected, which will affect the accuracy of the measurement and the reliability of the work of the watch. Therefore, water quality also has a great influence on the measurement performance and operational reliability of the ultrasonic mechanical heat meter.
Due to the existence of these fatal quality hazards of the above mechanical heat meter products, they are inherently determined by their basic working principle that they cannot have high long-term reliability and durability. Sixth, the water quality of domestic central heating is special, not only “ The hardness is high, and it is easy to scale at high temperature, and there are various kinds of particulate impurities (such as magnetized particles, iron filings), a small amount of bubbles, and even pollutants such as "flocs". In this relatively special state of centralized hot water supply, the demanding requirements of the meter for the mechanical heat meter product itself, coupled with the existence of inherently fatal quality hazards of some products, the lack of key production processes in the production process, the market of mechanical heat meter products It is not surprising that the current state of durability and reliability is low.
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