I. Overview Traditional flow integrator has been matured after long-term research and practice. It generally uses a barrier body to separate the flow channels to adjust the velocity distribution in the pipeline to achieve the purpose of rectification; this type of rectifier is mainly used in experiments. Room and flow calibration system. However, this method is apt to cause dirt clogging and increase resistance loss, so it is rarely used in industrial pipelines. Longitudinal end face adopts a special flow profiler (reported national patent), which has multiple functions of rectifying, increasing flow velocity and changing flow velocity distribution. Its structure size is small, and the length is only 1/3 of the inner diameter of the process tube, and can be directly carded. Mounted at both ends of the meter not only does not require additional additional straight pipes, but also reduces the requirement of the meter for upstream straight pipes. The experiment shows that: the upstream resistance of the instrument is two 90° elbows in a plane. Under normal circumstances, the upstream side of the intelligent vortex flowmeter should be equipped with a straight pipe with a length of more than 20 times the length of the pipe, and the intelligent vortex flowmeter plus The installed flow totalizer greatly reduces the requirement for the length of the upstream straight pipe, and its resistance is much smaller than that of a conventional reducer. More importantly, the lower limit flow rate can be reduced to 1/3 of the original, and the turndown ratio can be increased to more than 15:1. Set the pressure at the inlet of the rectifier to P1, the average flow velocity is V1, the velocity unevenness at a certain point is U1, the pressure at the outlet is P2, the average flow velocity is V2, and the velocity at the outlet is not the same through a certain flow line at an inlet point Uniformity is U2, along the streamline, derived from the Bernoulli equation: From equation (6), the effect of shrinkage ratio on the uniformity of the velocity at the outlet, ie, for a certain degree of non-uniformity of the inlet velocity, Two Φ50mm and φ40mm smart vortex flowmeters are equipped with rectifiers and installed on the φ80mm pipeline. The upstream of the instrument is a 90° elbow in one plane. The front end of the intelligent flow integrator is The second 90° elbow distance is 3 times the length of the inner diameter of the process tube, and the water calibration is performed. The process map is shown in Figure 3, and the experimental data is shown in Table 2. Experimental results show: China Milk Tea Maker,Machine For Milk Tea manufacturer, choose the high quality Automatic Milk Tea Maker,Machine Of Milk Tea, etc. Milk Tea Maker,Machine For Milk Tea,Automatic Milk Tea Maker,Machine Of Milk Tea Zhejiang Seaver Intelligent Technology CO., Ltd. , https://www.seavercoffee.com
Because of its unique performance, smart vortex flowmeters have always been valued by people and have been widely used. However, there are still two problems that plague people. First, flow fields occur due to the interference of flow blockers at the upstream of the instrument. Distortion affects the vortex's normal disengagement. In order to overcome the disturbance of the flow field, a longer straight pipe (generally 15 to 40 times the length of the inner diameter of the process pipe) needs to be fitted in front of the meter, which is difficult to satisfy in the actual site. Second, one of the main characteristics of smart vortex flowmeters is the wide range, which is generally around 10:1. It should be said that such a wide measurement range should be a relatively good performance, but in practical industrial applications, the maximum flow rate is much lower than that of the instrument. The upper limit value and the minimum flow rate are often lower than the lower limit value of the instrument. Some instruments often work near the lower limit flow rate, causing the meter's measurement accuracy to decrease. At this time, the signal is weak and the instrument's anti-interference ability is also reduced. In order to measure the small flow rate, people often use the traditional reducer tube whose inner cavity shape is a garden stage, and after the diameter reduction, the flow velocity at the measurement place is increased. The intelligent vortex flowmeter is operated within the normal flow velocity range, but this reduction method has a large structure size (general length is 3 to 5 times of the inner diameter of the process tube), and at the same time, the fluid is flowing through the reducing tube, and the diameter is reduced. A large number of rotating flows are generated at the site, which increases the local resistance loss and also distorts the flow field. Therefore, a straight pipe with a length of more than 15 times the inner diameter of the process pipe must be installed between the reducer and the meter for rectification, and the resistance loss along the way is increased (as shown in Fig. 1). This method increases the construction cost and also provides processing. , installation inconvenience. 
Second, the principle and analysis First of all, it should be pointed out that the traditional reducer can be reduced diameter, and with a smaller diameter flow meter to achieve the purpose of measuring small flow, but this method can not increase the instrument's turndown ratio, because it At the end, the flow velocity distribution of the pipeline is changed. We know that the theory and derivation of smart vortex flowmeters are based on infinite uniform flow fields. In actual closed circular tubes, they are non-uniform flow fields. The cross-sectional flow velocity distribution is a revolving paraboloid, although The reasonable column type makes the velocity distribution of the arcuate surface on both sides of the cylinder uniform, but in fact, the influence of the flow velocity distribution of the paraboloid of revolution on the process pipeline is objective. Experiments show that this effect is smaller when the flow rate is relatively large, or that the effect is within the allowable range. However, as the flow rate decreases, this effect becomes larger and larger. From a large number of calibration data, the instrument constant always follows. The decrease in flow increases. This shows that the difference between the flow rate at the sampling point and the average flow rate is increasing.
After using the flow totalizer (see Figure 2), the flow velocity at the cross-sectional area is gradually increasing. The increase in flow velocity at each point on the cross-section is not the same. The increase in flow velocity near the center is small, while the flow velocity is near the edge of the throat. Increase in size. 
The speed unevenness at the exit will be reduced by n2 times. Therefore, the flow velocity at the outlet tends to be even, and it is closer to the conditions of the uniform flow field of the intelligent vortex flowmeter theory, which not only makes the vortex stable, but also improves the measurement range of the instrument. In addition, this flow totalizer effectively suppresses disturbances during the conversion of fluid kinetic energy.
III. Experimental Verification Example 1: An intelligent vortex flowmeter with a bore diameter of 40 mm is installed on the process pipeline of φ40. The calibration has a turndown ratio of 8:1 that meets the accuracy of 1%. It is installed on the φ50 process pipeline and is installed on the instrument. Install the flow totalizer on both sides, with an accuracy of 1.0% in the 15:1 range.
Example 2: After two sets of 50mm and 40mm intelligent vortex flowmeters are fitted with rectifiers, they are installed on the 80mm diameter process pipelines for water calibration. The experimental data is shown in Table 1. 
1. When the flow rate of the pipeline is low, the flow totalizer is used to keep the instrument characteristics in good condition.
2. The flow totalizer is adopted. In the upstream of the instrument, the flow block is in the form of two 90° elbows in one plane. When the straight pipe is very short (3D), the drift of the meter constant is about 0.7%, indicating that the rectifier has Good flow adjustment performance. (The same type of upstream spoiler as the experiment does not contain the rectifier. When the length of the upstream straight pipe is 8 times the inner diameter of the process pipe, the meter constant offset is 2.0%!)
3. Install a flow totalizer in front of the instrument to display the measuring range of the instrument.
This is consistent with theoretical analysis.
Fourth, the resistance calculation Set the diameter of the process pipe D1, the density of the medium is Ï, the flow rate of the V1 smart vortex flowmeter pressure loss is ω1, the rectifier pressure loss is ω3, the total pressure loss is ω.
Ω1=0.3ÏV2 1(Pa)
After the rectifier is used, the diameter of the instrument is D2, and the flow rate at the smart vortex flowmeter is V2 and the pressure loss is ω2.
Ω2=1.3ÏV2 2=(V2/V1)2•ω1=(D1/D2)4•ω1
The pressure loss of the rectifier depends on the reduction ratio D2/D1, and the value is generally above 0.8. The pressure loss of the rectifier is:
Ω3=0.12ω2
So the total pressure loss ω is:
ω=1.12ω2=1.12(D1/D2)4×1.3ÏV2 1(Pa)
Example: A water metering system with a diameter of D1=100mm uses an intelligent vortex flowmeter as a flow meter. Its maximum flow velocity Vmax is 1m/s, and its minimum flow velocity Vmin is 0.3m/s. It is proposed to use a 100/80 rectifier to calculate The relevant parameters:
The reduced flow rate is V2:
V2max=(100/80)2×1=1.56m/s
V2min=0.47m/s
Ωmax=1.12(D1/D2)41.3ÏV2×1=1.12(100/80)4×1.3×998×1=3547(Pa)
V. Application Examples Installation of Flow Totalizer The full-tube intelligent vortex flowmeter has been widely used for the measurement of gases, water, and vapors, and its examples are not exhaustive and have received satisfactory results.
What is more worth mentioning is that the flow integrator is used in conjunction with a plug-in smart vortex flowmeter (see Figure 4) for large-diameter gas measurement, successfully solving the problem of large-diameter gas media, low flow rates, and variable flow rates. Large, allowing pressure loss to be a difficult problem. In the metallurgical industry, orifice meteor meters are generally used to measure large diameter gas. Due to its own limitations, it is difficult to meet actual measurement requirements. The problems are:
1 The gas contains dust and various impurities. After a period of time, a large amount of dust accumulates on the upstream side of the orifice plate. Various impurities are attached to the surface of the measuring element. As for the orifice plate, there is no accuracy at all, and at the same time, The problem of catheter blockage occurred. Due to the continuity of production, it is not possible to stop cleaning or replace the orifice.
2 Because of the low flow rate of the medium, in order to obtain a large differential pressure, the aperture of the orifice plate is generally relatively small, resulting in a large pressure loss. When the flow rate increases, the orifice plate does not function as a current limiting device. Some companies have to remove the orifice plate to meet production.
3 Ordinary orifice flowmeters have a range of approximately 3:1, often failing to meet actual operating conditions.
The gas flow metering system has been put into practical operation: flow totalizer and plug-in smart vortex flowmeter:
1 The inlet of the flow integrator is a smooth curve. When the medium flows through, it has the effect of self-cleaning and will not cause dust accumulation.
2 The flow rate increase at the reduced diameter can meet the requirements of the lower limit flow rate of the plug-in type wavble flowmeter, and the intelligent vortex flowmeter has a 10:1 turndown ratio, which fully meets the requirements of the gas measurement range.
3 The plug-in smart vortex flowmeter can remove the probe for regular or irregular cleaning with the continuous flow of the pipe. Meet the requirements of continuous production.
4 The pressure loss is small, the flow resistance of the probe part of the plug-in intelligent vortex flowmeter in the large-diameter pipe is negligible, the reduction ratio of the reduction part is generally greater than 0.7, and the maximum flow rate of the pipe is calculated at 25m/s. The pressure loss is only within 200Pa.
The above shows that this method is an effective method to solve large-scale gas metering.
VI. Conclusion Intelligent vortex flowmeters are used in conjunction with flow totalizers to form a new flow measurement system that allows the lower limit of flow measurement to be reduced (as the original 1/3) and the measurement range is expanded (15:1 or more). ), and can greatly reduce the instrument's requirement for the length of the upstream straight pipe. This is undoubtedly a significant advancement for a flowmeter. It broadens the application range of smart vortex flowmeters in gas, city gas, water, hot water, steam, oil, milk, liquid chemicals, chemicals The flow measurement of the product (the above-mentioned medium generally requires a lower limit flow rate and a wide measurement range) will play a prominent advantage. The actual application of the flow totalizer in industrial users also shows that the flow totalizer simplifies the instrument installation process and greatly reduces the project cost.
Research and application of flow integrator is a typical example of research on flow application technology, and its own research needs to be further in-depth. At the same time, we should further pay attention to other application research related to flow turbulence and make full use of existing ones. Technical equipment resources really solve some difficult problems in flow measurement.
November 21, 2023