According to relevant information reports: It is found that about 60% of the flowmeters selected by the measuring method are inappropriate or incorrectly used, and some of them are incorrectly arranged and installed, although using appropriate measuring methods. This shows that the correct selection and use of flow meters is not an easy task.
1. Measuring method and instrument selection step
1.1 Determine if you really want to install a flow meter
If you only want to know if the fluid in the pipeline is flowing, its general flow, then you can achieve this goal at a lower cost by using a flow window or flow indicator. They are simple structures. They often have a moving body (plate, ball, wing wheel, etc.) to show whether the fluid is flowing. Some of them have a high degree of knowledge of the speed of flow, and the accuracy is very low. The error is generally between 20-30%. Or bigger.
The domestic flow meter manufacturing industry pays insufficient attention to the peek window and the flow indicator. Only a few companies provide products, so the design unit and the direct user ignore such simple instruments, or want to use the single type, can not be in multiple forms. Choose a combination product. On the other hand, in the introduction of petrochemical sets from abroad, mobile viewing windows or indicators are installed at more stations.
If the measurement requirements are higher than the above, indicating a flow error between 2-10%, install a flow meter. If it is considered that the differential pressure type instrument is selected according to the following step, it is not necessary to specifically install a flow sensor such as a orifice plate fluid, and the portable ultrasonic flowmeter can be used by using an elbow flowmeter or an external clamp.
In order to correctly and effectively select flow measurement methods and instruments, it is necessary to be familiar with the techniques of flow meter and fluid characteristics of production process, and to integrate economic factors. There are five factors in summary, namely performance requirements, fluid characteristics, and installation requirements. , environmental conditions and costs.
There may be several options for the instruments that can be used in an application site. For example, when you choose, you can make a decision based on past experience and simply combining the initial installation costs, thus losing the opportunity to choose the most suitable instrument. For example, if the flow range of the meter does not match the actual flow rate, and the instrument that is not required for measurement is too complicated and expensive, the instrument will not work properly after installation. These situations are not uncommon. If the vortex street fluctuates sharply, the orifice plate is out of range. Occasionally, accidents such as easy-to-flash liquid burns the turbine of the turbine flow meter, and the negative pressure drops the electromagnetic flowmeter lining.
1.2 Primary selection measurement issuance
Xxxx determines that the flow meter must be installed to further understand the usage requirements and various conditions. First, according to the type and characteristics of the fluid, the measurement method that the exclusion method cannot and should not be used in the “primary selection table†is taken in the second step for in-depth consideration and analysis.
1.3 Analysis factors
Xxxx collects samples, technical data and selection manuals from various manufacturers of primary selection instruments according to the schemes determined by the primary selection, fully understands the performance of the instrument specifications; and separately according to performance requirements and instrument specifications, fluid characteristics, installation sites, and environmental conditions. And the five aspects of economic considerations, according to the issues raised in the following sections, one by one analysis, list comparison. Considering the order is different from the primary selection according to the measurement purpose and focus, generally starting with "performance requirements and instrument specifications", and then considering other factors as shown in Figure 1. If the applicable object considers that "economic factors" are the main factors (such as the low pumping cost required for large-diameter transport and the small loss due to measurement errors in business accounting requirements), then when considering another factor of "performance requirements and instrument specifications", Sometimes it is necessary to revert to considering the factors of migration, and the five factors are considered together.
Copper Capillary Tube,Capillary Tubing,Air Conditioner Copper Capillary,Air Conditioning Capillary Tubing
Suzhou Green New Material Technology Co., Ltd. , https://www.szgreenvip.com