1、 Instrument Introduction:
Ball valve insertion target flowmeterIt adopts mature and reliable force weighing sensor technology, which can optimize the flow rate, flow rate (or temperature and pressure detection of working conditions) according to the requirements of working conditions, fully reflecting the high-tech nature and cost-effectiveness of today's mechatronics products.Mainly used for flow measurement of high viscosity and low Reynolds number fluids, it has gone through two major development stages: pneumatic meters and electric meters.The data processing of this target flowmeter system adopts MCU technology from Texas Instruments Incorporated and combines modern microelectronics technology to develop a highly reliable and accurate industrial flow measurement and control instrument.
2、 Structure and working principle:
1. Structure:
Ball valve insertion target flowmeterIt mainly consists of a measuring tube (housing), a new type of sensor (including flow blocking components), an accumulation display, and an output part. According to different media and working conditions, suitable sensors must be selected. Therefore, providing accurate measurement objects and parameters by users and selecting appropriate sensors by manufacturers are the key to whether the product can measure accurately.
2. Working principle:
When the medium flows in the measuring tube, the pressure difference generated by its own kinetic energy passing through the blocking element (target flowmeter) exerts a force on the blocking element, and the magnitude of the force is proportional to the square of the medium flow velocity. Its mathematical expression is as follows:
F=CdAρ? V2/2
In the formula: the force acting on the F blocking component (kg)
Cd object drag coefficient
The axial projection area of the measuring tube by the A blocking component (mm2)
Medium density under ρ condition (kg/m3)
The average flow velocity of V medium in the measuring tube (m/s)
The force F received by the blocking element (target) is transmitted to the sensor through a rigidly connected transmission element (measuring rod), and the sensor generates a voltage signal output: V=KF
In the formula: V - voltage output by the sensor (mV), K - proportionality constant,
F - the force acting on the flow barrier (target) (kg),
After pre amplification, AD conversion, and computer processing, this voltage signal can obtain the corresponding instantaneous flow rate and cumulative total amount.
3、 Application scope:
Ball valve insertion target flowmeterThe measurement accuracy, combined with its anti-interference, anti impurity performance, lightweight and reliable characteristics, is widely used in various fields such as petroleum, chemical, energy, food, environmental protection, water conservancy, etc. From its effectiveness after use, the BL type flowmeter has extremely broad applicability, namely:
1. Suitable for various pipe diameters, ranging from 15-2000mm to larger.
2. Suitable for high and low temperature media: from -196 ℃ to+450 ℃.
3. Suitable for high-pressure conditions: from 0 to 42Mpa (gauge pressure).
4、 Advantages:
1. The entire instrument is designed with no movable parts, an insertable structure, and easy disassembly;
2. Multiple anti-corrosion and high/low temperature resistant materials can be selected (such as Hastelloy, titanium, etc.);
3. The whole machine can be made into a fully sealed (welded form), without any leakage points, and can withstand high pressure of 42MPa;
4. The instrument is equipped with a self checking program, and the fault symptoms are clear at a glance;
5. The sensor does not come into contact with the measured medium, there is no wear on the components, and it is safe and reliable to use;
6. Dry calibration method can be used on-site, namely the weight hanging method. Single key operation can complete calibration;
7. There are multiple installation methods to choose from, such as online plug-in, which has low installation costs;
8. Equipped with integrated temperature and pressure compensation, directly output quality or standard square;
9. It has optional small signal removal, non-linear correction, and selectable filtering time;
10. Capable of accurately measuring gas and liquid flow rates under various working conditions of room temperature, high temperature of 500 degrees, and low temperature of -200 degrees;
11. Accurate measurement, with an accuracy of up to 0.2%;
12. Good repeatability, generally 0.05-0.08%, fast measurement;
13. The pressure loss is small, only about 1/2 △ P of the standard orifice plate;
14. Strong anti-interference and anti impurity ability;
15. The flow range can be changed by replacing the blocking element (target) according to actual needs;
16. Low power battery on-site display, capable of online direct reading of readings, and the display screen can simultaneously read instantaneous and cumulative flow rates as well as percentage bar charts;
17. Easy to install and maintain;
18. Multiple output forms, capable of transmitting various parameters remotely;
19. Strong shock resistance, capable of measuring pulsating flow within a certain range;
5、 Performance indicators:
Tested medium: liquid; Gas; Steam;
Nominal diameter: flange type 15-500mm clamp type 15-500mm insert type 65-3000mm;
Nominal pressure: 0.6-42MPa 0.6-42MPa 0.6-42MPa;
Medium temperature: -200 ℃ to+500 ℃ or higher;
Degree: ± 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% to 0.08%;
Power supply: Equipped with a built-in lithium battery (3.6V); External power supply 24VDC;
Output format: On site display; 4-20mA two-wire system; Pulse 0-5V; RS485/RS232; GPRS wireless remote transmission;
Measurement tube material: carbon steel; stainless steel; It can also be negotiated and provided according to user requirements;
Explosion proof grade: intrinsic safety type (ExiaICT4); Explosion proof type (ExdIICT4);
Protection level: IP65; IP67；
Flange specifications: The flange specifications for the flowmeter connection comply with the GB/T series standards, and can also be specially processed according to user requirements.
6、 Installation precautions:
1. There should be a straight pipe section before and after the measuring tube, and the diameter of the straight pipe section should be equal to the diameter of the flow meter measuring tube. If the diameters are different, a reducer should be used to connect them so that the inlet diameter is the same. The length of the upstream straight pipe section of the flowmeter is generally not less than 6-20D, determined according to different types of upstream flow resistance components, and the downstream straight pipe section is not less than 3-4D. The flowmeter is usually calibrated in a horizontal position and is generally installed in a horizontal pipeline. When it must be installed in a vertical pipeline, the hanging weight method must be used to calibrate the vertical installation status of the flowmeter, and the fluid direction should be from bottom to top.
2. For the convenience of maintenance and to prevent one-way force when the flowmeter is activated, a bypass pipeline is installed in parallel. A discharge pipe is installed downstream of the flowmeter to facilitate instrument cleaning and blowing. It is more necessary for measuring dirty fluids or media that are prone to solidification and crystallization. The target plate and measuring tube (body) should be installed coaxially. According to previous tests on a certain caliber, if the center of the target plate deviates 1mm from the center of the pipeline, it may cause a deviation of 1% to 2% in the flow coefficient. However, if the deviation is 1mm from the center of the pipeline, the impact is not significant;
3. When installing an explosion-proof target flowmeter, attention should be paid to checking whether there are explosion-proof markings and explosion-proof certificates, and whether the explosion-proof equipment is intact.
4. For small-diameter flow meters, due to the small diameter and relatively heavy weight of the flow meter, additional brackets should be installed to support the flow meter to prevent pipeline deformation or vibration during operation. For large-diameter flow meters, there is no need to install additional brackets.