Obtaining accurate information is essential for selecting and sizing flowmeters. Many applications include materials that have little information about their physical properties, and the best guess is the only solution available. Even when fluid information is available, The operating conditions and operation of the flowmeter are different from what was considered when selecting it. Therefore, many processes are not well defined and close to the operating conditions, and therefore the range intended for flowmeters and what exists in practice is different.
The above indicates that the main problems of the flowmeter are probably related to the incorrect definition of the forming conditions and fluid properties.
The characteristics of such information often include judgments based on familiarity with the process fluid used. The use of a manual for physical properties is sufficient only for ordinary cases, but process fluids are often mixed and therefore no specific information is available about them.
Those who select or specify a flowmeter should be careful not to generate process data independently without the assistance of a qualified process engineer. Even if the fluid characteristics are known, the flowmeter selection process is challenging.
Attempts to combine the evaluation of process data and operating conditions lead to a different set of requirements that may not cause sufficient attention in the selection of flowmeters and may be considered incompletely in process data. If the state of the process is not well defined, this fact must be clearly recorded. For example, in most cases the accuracy of instrumentation measurements is not taken into account until after commissioning, so design conditions should be fully documented as far as possible.
Flowmeter efficiency is often achieved by accurately measuring the resulting flow rate. Therefore, for the most appropriate measurement, the accuracy of the entire flowmeter system may need to be evaluated; However, due to production errors in other equipment in the system and the lack of confidence in the physical characteristics and operating conditions, flow meters have little effect on the accuracy of the whole system.
In some applications, repeatability is thought to be a good measure of flowmeter performance. Some people believe that triba in all applications, as long as the measurement is repeatable, the numerical value of the flow is insignificant. This type of argument may be correct in some applications; However, it should be noted that the flow rate reproducibility can be a function of the Reynolds number and other factors.
Changes in temperature, cost, pressure, density, and the like can displace a point in the flowmeter at which it operates, thereby affecting the total repeatability of the measurement. Therefore, reproducibility should not be used as an absolute criterion in determining performance.
The flowmeter response to flow, which is often assessed for the time required to measure step change in flow, is an important factor, especially in applications where the flow is relatively short.
In cases where a fluid is well known, knowing the fluid name can be useful in gathering information about its physical properties from public sources such as manuals. These sources can be used as the main sources of information or information obtained from other sources can be examined. Specific material data is not available in many processes. This problem puts a heavier burden on people who are supposed to determine the flow meter. The data on the physical properties and adaptability of materials cannot be determined with certainty.
Fluid types include liquids, gases, and vapors. These divisions alone are not enough to select a flow meter. The fluid may be clean, dirty, liquid / solid slurry, or a combination of other modes. The slurry should be defined based on the percentage, type and size of solid particles and whether it is abrasive or fibrous or has unusual flow characteristics. Expensive properties on liquids can be inherently Newtonian or non-Newtonian.
Corrosion of materials in operating conditions can determine the materials compatible with it for the equipment building.
The compatibility of metals is often determined by the materials used in plumbing, while the compatibility of other materials such as Teflon, Vuitton and the like is determined by tests, calculations based on chemical specifications or tests of manufacturers. And is generally much later than the accepted flowmeter services, so the plumbing material should be considered as a starting point.
Pressure and temperature
Operating pressure and temperature limits should be considered in the flowmeter, especially where the fluid is intended for gas. In cases where temperature and pressure changes are large, compensation may need to be used. The degree and strength of the flowmeter flange is determined by the maximum pressure and operating temperature of the fluid, and in addition to any special studies that may be necessary for process and flowmeter considerations, the power of the flanges used in piping can usually be deduced.
Density and specific gravity
The specific operating weight of the liquid is required for sizing and calibrating the flowmeter. While the specific gravity of a liquid is practically always assumed to be constant, where there are large variations in temperature and can affect the accuracy of the measurement, it may be necessary to compensate for the temperature. In gas and steam applications, fluid density is generally required in standard and operational conditions to be applied to the flowmeter. In the case of non-ideal gases and vapors, this will result in a correct conversion to a standard unit. Compensation for density fluctuations is often done by compensating for temperature and pressure or by measuring density.
Expensive on fluid is needed to estimate the Reynolds number and to determine the various usable flowmeter technologies. Awareness of the behavior of expensive zinc in liquid applications is valuable because relatively small changes in temperature may lead to large changes in expensive zinc. Large variations in the Reynolds number may influence the choice of flowmeter. If this information is not available, it may be necessary to perform a flowmeter test or use a flowmeter that is not affected by the Reynolds number.
The operating range of the flowmeter is a wide range of flowmeters in which the flowmeter works properly and from which the maximum to minimum ratio can be calculated. Because digital flowmeters may not be able to operate below the minimum flow rate, the minimum flow rate should be considered carefully low enough to support all operating conditions. Analog flowmeters typically operate from zero to full range, although their accuracy is low at near zero.
Other physical characteristics
Knowledge of additional physical properties of the fluid may be essential when considering specific technologies. For example, in magnetic flowmeter applications, liquid electrical conductivity is required, in thermal flowmeter applications, thermal capacity and fluid conductivity are required. Other information such as the amount of solids in the fluid, vapor pressure and the like should be considered.
The size and thickness of the pipe in which the flowmeter is installed is often known, although the size of the flowmeter is determined by the operating conditions and range of the flow and may differ from the nominal size of the pipe.
Any limitations on the maximum acceptable pressure drop created by the flowmeter must be specified as soon as it is selected. Often, process limitations limit this amount of pressure drop. In some liquid applications, high pressure drop leads to bubbling and cavitation, and a lot of energy is lost.
Tube vibration should not be ignored. To ensure proper installation, the installation requirements must be in line with the plumbing design.
It should be noted that the pulse or natural state is constant and constant because some technologies are safer than the effects of the Dubai pulse. It may be necessary to use plus dampers to coordinate with mechanical resources and the process.
Run straight pipe
Many flowmeters require that the flow velocity shape upstream and downstream be correct. The common method is to use the pipe directly and at a certain length upstream and downstream of the flowmeter, which creates a symmetrical shape of the flow and eliminates the rotation in the fluid.
The ability to run a sufficiently straight length in the piping system without incurring additional costs is an important item in selecting a flow meter. Due to the fact that not all piping systems can use direct pipe length components, the problem can be solved by using technologies that are less sensitive to them.
Awareness of the situation around the flow meter can help you choose the right one because some flow meters are not suitable for harsh environments. This is revealed by comparing flow meters designed for laboratory environments and those designed for dirty industrial environments such as open environments.
Repair and maintenance
The amount of repairs that need to be done on the flowmeter is very important in choosing it. Sensors that need to be cleaned daily or replaced weekly are a hassle of maintenance and are not tolerable in industries with continuous flow. Some other flowmeter technologies increase reliability. Lightening may be required to achieve greater reliability.
Access to parts and service
Access to spare parts on site and at local service centers are important issues in choosing a flow meter. However, choices based on the availability of parts and service centers may lead to problems. The choice should be made based on technical considerations and then check the flowmeters where spare parts and service are available.
The cost and cost of the installed flowmeter, including the flowmeter cost, accessories, plumbing, and labor that completes the operating flowmeter system, must be considered in the selection process. Where auxiliaries such as converters are used, their prices should be checked. The flow meter selection process emphasizes further consideration of technical rather than economic considerations. It should be noted that misuse of flowmeters, although not expensive, indicates an economic error. For this reason, technical evaluation takes precedence over economic evaluation.
The economic measure of energy consumption can be an irreversible pressure drop in a double flowmeter that can be easily calculated. Annual energy consumption can be significant and choosing the right flowmeter can significantly reduce energy costs. It should be noted that in many applications, because the stored energy can not be used and evaluated, the correct choice of flowmeter measurement does not provide economic benefits. The possibility of energy recovery should be considered because the energy stored annually can be much higher than the cost difference due to the choice of flow meter with less pressure drop, especially in large pipes.
Considerations for future use of the flowmeter can affect the selection process. Sufficiency and the ability to measure correctly over a wide range of operating conditions for predictable changes must be considered to prevent future flow meter replacement.
Rose Calibration Company in Melbourne, Australia with over ten years of experience provides all calibration, maintenance, and repair services throughout Australia. If you live in Sydney, Melbourne, Adelaide, Perth, Geelong, and Brisbane, you can receive your quote in less than two hours by fill-up the form via the “Booking” link.