Insert target meter

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The plug-in target flowmeter adopts mature and reliable force weighing sensor technology, which can …

I. product overview
ZW series of BSL plug-in target flowmeter is based on the traditional target flowmeter, with the development of new sensors, microelectronics technology research and development into a new type of capacitance induction flow target flowmeter, it has both orifice plate, vortex flowmeter is the characteristics of the moving parts, and has a high sensitivity and accuracy of the comparable to those of volumetric flowmeter, span a wide range.

Ii. Structure and working principle
1. Structure
Zw-bsl series insert target flowmeter mainly consists of measuring tube (housing), new type sensor (including choke element), integrating display and output part. Appropriate sensors must be selected according to different media and working conditions. Therefore, accurate measurement objects and parameters provided by users and appropriate sensors selected by manufacturers are the key to accurate measurement of products.
2. Working principle:
When the medium flows in the measuring tube, the pressure difference generated by its kinetic energy passing through the flow arrester (target flowmeter) will exert a force on the flow arrester, which is proportional to the square of the flow velocity of the medium. The mathematical expression is as follows:
CdA rho/V2 / F = 2
Where: the force (kg) exerted on F flow arrester
The drag coefficient of the Cd object
A axial projection area (mm2) of flow arrester on measuring tube
Rho medium density on condition (kg/m3)
Average velocity of V medium in measuring tube (m/s)
The force F received by the choke (target) is transmitted to the sensor through the rigidly connected transmitter (measuring rod), and the sensor generates voltage signal output: V=KF
Where: V -- voltage (mV) output of the sensor, K -- proportionality constant,
F -- force (kg) on the choke (target),
After the voltage signal is preamplified, AD converted and processed by computer, the corresponding instantaneous flow and cumulative total amount can be obtained.
Iii. Application:
ZW series of BSL plug-in target flowmeter is mainly used to solve the high viscosity, low Reynolds number fluid flow measurement, has experienced the pneumatic tables and electric table two stages of development, intelligent target flowmeter is the original strain chip target flowmeter measurement principle on the basis of, used for gas categories: gas, air, hydrogen, natural gas, nitrogen gas, liquefied petroleum gas, hydrogen peroxide, flue gas, methane, butane, and so on.
Iv. Main features:
1. The whole instrument has no moving parts in the design, and is of plug-in structure and easy to disassemble;
2, can choose a variety of anti-corrosion and high and low temperature resistant materials (such as hastelloy, titanium, etc.);
3, the whole machine can be made into a full seal without dead Angle (welding form), without any leakage point, can withstand 42MPa high pressure;
4. The instrument is equipped with self-test procedure, and the fault phenomenon is clear at a glance;
5. The sensor is not in contact with the medium under test, and there is no wear of parts, so it is safe and reliable to use;
6. Dry calibration method can be adopted in place, that is, weight hanging method. Single key operation can complete calibration;
7, with a variety of installation options, such as online plug-in, low installation cost;
8, with integrated temperature and pressure compensation, direct output quality or standard;
9. Optional small signal removal, nonlinear correction and filtering time;
10. Able to accurately measure the flow of gas and liquid under various working conditions of room temperature, high temperature 500 c and low temperature -200 c;
11. Accurate measurement, accuracy up to 0.2%;
12, good repeatability, generally 0.05 ~ 0.08%, rapid measurement;
13. Small pressure loss, only about 1/2 of standard orifice train P;
14, anti-interference, anti-impurity ability is very strong;
15. The flow range can be changed by changing the flow arrester (target) according to actual needs;
16, low power consumption battery field display, can online direct reading display value, display screen can read instantaneous and cumulative flow and percentage bar chart;
17. Easy installation and easy maintenance;
18, a variety of output forms, can be transmitted to a variety of parameters;
19, strong earthquake resistance, a certain range of pulsating flow can be measured;
V. technical parameters:
Medium under test: liquid; Gas; Steam;
Nominal diameter: flange type 15 ~ 500mm clamped type 15 ~ 500mm plug type 65 ~ 3000mm;
Nominal pressure: 0. 6 ~ 42MPa 0.6 ~ 42MPa 0.6 ~ 42MPa
Medium temperature: 200 ℃ ~ + 500 ℃ or higher temperature;
Accuracy: 0.2% 0.5% 1.0% 1.5%;
Range: 1:3 (liquid) 1:10 (steam) 1:5 (liquid, gas) 1:10 (liquid, gas) 1:10 (steam);
Compensation form: temperature compensation; Pressure compensation;
Repeatability: 0.05% ~ 0.08%;
Power supply: built-in lithium battery (3.6v); External power supply 24VDC;
Output form: field display; 4-20ma two-wire system; Pulse 0 ~ 5V; RS485 / RS232. GPRS wireless remote transmission;
Measuring tube material: carbon steel; Stainless steel; It can also be provided according to the user's request through negotiation;
Explosion-proof grade: intrinsically safe (exiai tc 4); Flameproof (ExdIICT4);
Protection level: IP65; IP67.
Flange specification: the flange specification of flow meter connection is GB/T series standard, or can be processed according to the requirements of customers.
Vi. Installation precautions:
1. There should be straight pipe sections before and after the measuring pipe. The diameter of the straight pipe section should be equal to that of the flow meter measurement pipe. The length of the straight pipe segment on the upstream side of the flowmeter is generally not less than 6~20D. It is determined according to different types of upstream choke, and the length of the straight pipe segment on the downstream is not less than 3-4d. The flowmeter is usually calibrated at the horizontal position and is usually installed in the horizontal pipeline. When it must be installed in the vertical pipeline, the flowmeter must be calibrated at the vertical installation state with the hanging weight method, and the direction of the fluid should be from bottom to top.
2. In order to facilitate maintenance and prevent unidirectional force when the flowmeter is put into use, parallel installation of the discharge pipe downstream of the bypass pipeline flowmeter is necessary to facilitate instrument cleaning and purging, especially for measuring dirty fluid or medium that is easy to solidify and crystallize. The target plate and measuring tube (gauge body) should be installed in the same axis. According to the test on a certain caliber, if the center of the target plate and the center of the pipeline deviate from 1mm up and down, it may cause a deviation of 1% to 2% of the flow coefficient, but the influence is not obvious if the deviation is 1mm from left to right.
3, the installation of explosion-proof target flow timing, should pay attention to check whether there is explosion-proof mark and explosion-proof certificate, explosion-proof equipment is in good condition.
4. For small-diameter flowmeter, because the pipe diameter is small and the flowmeter is relatively heavy, in order to prevent pipe deformation or vibration during work, a support should be set to support the flowmeter. It is not necessary to set support for large diameter flowmeter.
Vii. Precautions for use:
1. Before the flow of the fluid, the downstream valve of the flowmeter should be closed and the upstream valve should be opened to allow the fluid to enter the pipe section of the flowmeter. Then slowly open the downstream valve of the flowmeter, and close the bypass valve at the same time, so that the fluid increases slowly. Do not open the valve suddenly and impact the target plate to damage the instrument.
2. After long-term operation of the flowmeter, besides cleaning the target plate and measuring the scale of the pipe, the weight method should be adopted to check whether there is any change in the characteristics of the force converter. The hanging weight method is to apply weight gravity in the center of the target plate in the same direction as the flow, adjust the meter, and the force corresponding to the flow meter's upper limit, that is, F 1 calculated according to formula (16.6). Other flow points are added with relevant weights to read the output signal of the meter and check the basic error and linearity of each point. This method is described in the manufacturer's instruction manual or other information.
3. There is a difference between the forces acting on the target plate by the fluid and the forces acting on the weight, so the weight method cannot completely replace the real flow calibration. To achieve high accuracy, the necessary real flow calibration is required.
4. When copying or changing the target plate, the processing accuracy of the target plate should be paid attention to, otherwise the flow coefficient will be affected. Test data show that, for target flowmeter with port =0.8 and pipe diameter DN=25mm, if the target diameter deviation is 0,03mm, the flow coefficient deviation is 1%. The machining precision and surface roughness of the target also affect the flow coefficient.
5, flow meter is running, if discover the output value, check the power conversion system is normal, may be due to the fluid flowing through the target board at its downstream vortex street, caused by vibration in the target bearing, it is about the size and velocity, medium physical parameters (density and viscosity) and so on, can be in force transformation and electrical signals take measures to improve the damping in the system.
Viii. Matters needing attention in type selection:
The target type flowmeter is suitable for many occasions and for the measurement of various media. In order to ensure satisfactory results, it is suggested to pay attention to the following matters when selecting the type: