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Product details
Detailed Introduction
1、 Product Overview:
The clamped target flowmeter is named after its structure, which clamps the flowmeter with a matching flange and locks it with fasteners. The narrow width of the clamp type flowmeter pipeline makes it easy for the flowmeter to reach the fluid operating temperature in a short period of time. Therefore, it is widely used in high-temperature fluids such as liquid sulfur (liquid sulfur), liquid paraffin (liquid wax), emulsified asphalt, latex, etc. that are prone to solidification at room temperature. This type of medium has the characteristics of high viscosity, low flow rate, and easy coagulation and blockage. High temperature clamp type target flow meters have good adaptability to this type of medium.
2、 Structure and working principle:
1. Structure
The clamped target flowmeter mainly consists of a measuring tube (housing), a new type of sensor (including flow blocking element), 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, due to its own kinetic energy and pressure difference with the target plate, a force is generated on the target plate, causing a slight displacement of the target plate. The magnitude of the force is proportional to the square of the medium flow velocity. The force acting on the target plate is transmitted through the target rod, causing a slight change in the elastic body of the sensor, thereby breaking the balance of the bridge composed of surface mount capacitors. Generate a voltage signal corresponding to the force exerted by the flow rate on the target plate: the flow rate is proportional to the square of the voltage generated by the bridge due to the influence of fluid flow characteristics. Its mathematical expression is as follows:
F=CdAρV2/2
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 - force acting on the blocking element (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 scenarios:
Clamp on target flow meters have been widely used for measuring semi water gas, coke oven gas, heavy oil, residual oil, asphalt, liquid paraffin, toluene, sulfuric acid, natural gas, flue gas, sewage, purified water, and other special media.
4、 Main features:
1. Suitable for various pipe diameters: 15-2000mm to larger.
2. Suitable for high and low temperature media: -196 ℃ -+450 ℃. Can accurately measure the flow rate of liquids, gases, vapors, viscous media, and various fluid media under various normal temperature, high temperature, and low temperature conditions.
3. Extremely high sensitivity, capable of measuring ultra-low flow rates, and can measure low flow velocities of 0.08m/s.
4. Suitable for high-pressure working conditions: 0-42Mpa.
5. No movable parts, high accuracy.
6. Good repeatability, generally 0.1-0.08%, fast measurement.
7. Accurate measurement, high precision, and total measurement can reach 0.2%.
8. Good anti vibration and anti electromagnetic interference, can be used for dry calibration or weight hanging method.
9. Body material: carbon steel, 304, 316, 316L.
10. Power supply mode: 3.6V lithium battery; 24VDC power supply; Dual power supply: 3.6V lithium battery+24VDC power supply.
5、 Technical parameters:
1. Measurement range 0-400t/h;
2. Accuracy level: 0.5% FS 1.0% FS 2.0% FS;
3. Output signal: 4-20mA two-wire system output is linearly related to flow rate;
4. Power supply voltage: 12-36VDC;
5. Nominal pressure: 1.6 2.5 4.0 6.4MPa;
6. Environmental temperature: -30 ℃~60 ℃ (special: -40 ℃~80 ℃);
7. Medium temperature: ordinary type ≤ 100 ℃ (without heat sink);
High temperature type ≤ 400 ℃ (with heat sink);
8. Liquid receiving material: The measuring chamber is made of carbon steel or 1Cr18i9Ti; The rest is 1Cr18Ni9Ti;
9. Shell material: cast aluminum;
10. Flange standard: DIN2501 special type to be selected by the user;
11. Cable interface: M20 * 1.5 (internal thread);
12. Protection level: IP65;
13. Load characteristics: Maximum load resistance=50 * (power supply voltage -12)=600 Ω @ 24V;
14. Alarm output: collector open circuit form, maximum input current of 100mA, maximum switch voltage of 30VDC, with deviation band control;
15. Pulse output: with a minimum pulse width of 50ms, capable of dual channel output;
16. The maximum cumulative flow display value is 50000 units, automatically reset;
17. Damping time: adjustable from 1 to 100 seconds;
18. Explosion proof form, explosion-proof mark, explosion-proof certificate number.
6、 Installation instructions:
1. Normal temperature, low temperature, and high temperature flow meters are installed horizontally, vertically, or upside down depending on different working conditions (according to the factory calibration sheet);
2. When the working temperature of the medium is above+300 degrees, users should take insulation measures for the flowmeter housing to prevent thermal radiation damage to the meter head (the working temperature of the meter head is -30 to+70 degrees). Similarly, for media with a working temperature below -100 degrees, anti freezing measures should also be taken;
3. To ensure accurate measurement of the flowmeter, it is required to set up front and rear straight pipe sections;
4. To ensure that the flow meter does not affect the system operation during inspection and replacement, bypass valves (3) and shut-off valves (1, 2) should be installed as much as possible;
5. Vertical installation can be used due to process requirements, and the flow direction of the measured medium can be from bottom to top or from top to bottom, but it should be explained to the supplier when ordering;
6. The diameter of the flowmeter should be as similar as possible to the diameter of the connected pipeline to reduce flow interference and measurement errors;
7. The flowmeter housing must be reliably grounded. If there is no grounding condition, it should be explained to the factory.
7、 Normal working environmental conditions:
1. Atmospheric pressure: 86-106kPa;
2. Surrounding environmental temperature: -20 ℃ to+60 ℃ (8 ℉ to 140 ℉);
3. Relative humidity of the surrounding environment: ≤ 95% RH (+25 ℃);
4. Explosion proof flow meters can be applied to hazardous areas in Zone 1 and Zone 2 containing explosive gas mixtures of Class IIA, IIB, and IIC T1 to T4 groups;
5. Intrinsic safety flow meters are suitable for hazardous areas in Zone 0, Zone 1, and Zone 2 containing explosive gas mixtures of Class IIA, IIB, and IIC T1 to T4 groups.
8、 Installation and usage precautions:
(1) 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 needs to 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, 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 ********** flow meters, due to their small diameter and relatively heavy weight, additional brackets should be installed to support the flow meters in order to prevent pipeline deformation or vibration during operation. For large-diameter flow meters, there is no need to install additional brackets.
(2) Precautions for use
1. Before fluid flow, the downstream valve of the flowmeter should be closed and the upstream valve should be opened to allow fluid to enter the flowmeter section. Then slowly open the downstream valve of the flowmeter and close the bypass valve to allow the fluid to slowly increase. Avoid suddenly opening the valve to impact the target plate and damage the instrument.
2. After long-term operation of the flowmeter, in addition to cleaning the scale on the target plate and measuring tube, the hanging weight method should be used to check whether the characteristics of the force converter have changed. The hanging weight method is to apply a weight gravity in the same direction as the flow at the center of the target plate, adjust the instrument, and apply the force corresponding to the upper limit of the flow meter, which is calculated as F1 according to equation (16.6). Other flow points are added with relevant weights, and the output signal of the instrument is read to check the basic error and linearity of each point. The 'hanging weight method' is described in the manufacturer's product manual or other materials, and can also be referred to.
3. The force exerted by fluid on the target plate is still different from the force exerted by hanging weight, so hanging weight method cannot completely replace real flow calibration. To achieve high accuracy, necessary real flow calibration is still necessary.
4. When copying or modifying the target plate, attention should be paid to the processing accuracy of the target plate, otherwise it will affect the flow coefficient. Experimental data has shown that for a target flowmeter with a diameter of DN=25mm and a target diameter deviation of 0.03mm, the flow coefficient deviation is 1%. The processing accuracy and surface roughness of the target plate also have an impact on the flow coefficient.
5. When the flowmeter is running, if the output value is found to be shaking and the force conversion system is normal, it may be due to the fluid flowing through the target plate and generating vortex streets downstream, causing the target to vibrate under force. It is related to the flow velocity, physical parameters of the medium (density, viscosity), etc. Damping measures can be taken in the force conversion and electrical signal system to improve it.
9、 Fault handling:
(The flowmeter comes with a fault self checking program, and users can check some of the reasons through the display screen!)
1. When the flow velocity of the measured medium in the pipeline is zero, the instantaneous flow rate value indicated by the flowmeter is not zero. The main reasons for this phenomenon are:
a、 The uneven levelness of the flow meter before and after installation results in the axial horizontal force generated by the tilting of the target plate and target rod, leading to the existence of instantaneous flow rate;
b、 The flowmeter operates for a long time, causing slight changes in the internal stress release of its sensor;
c、 During installation or operation, severe overload causes zero drift;
The above three methods can all refer to the steps and methods for clearing flow meters.
d、 Poor grounding of flowmeter housing;
Solution: The user needs to reconnect to the ground.
e、 The target, target rod, and measuring tool are stuck by debris;
Solution: Close the front and rear valves of the flowmeter, use tools to loosen the connecting bolts between the transition part of the flowmeter and the measuring tube, gently shake the transition part or remove it, clean up debris, and reset it as it is.
2. The abnormal increase in the reading of the flowmeter during operation is mainly caused by:
a、 There are filamentous and strip-shaped impurities hanging on the target film and target rod;
Handling method: Refer to the method for handling miscellaneous items.
b、 Under high blockage conditions, severe blockage occurs between the target plate and the target rod, resulting in an increase in the projected area of the force bearing element target plate along the axis of the measuring tube, that is, a decrease in the annular flow area between the target plate and the measuring tube. As a result, under the same flow rate, the force on the sensor increases, ultimately leading to an abnormal increase in the flow reading;
Solution: Remove the transition component and use tools to remove any debris from the target plate, target rod, and inner wall of the measuring tube.
3. There are many reasons for the large measurement error, and the main reasons are as follows:
a、 During installation, there is a significant misalignment in the concentricity between the flowmeter and the connecting pipeline, and the sealing gasket is not concentric, resulting in the formation of a throttling resistor and greatly affecting the measured medium.
Qualitative flow state;
Solution: Adjust the installation status.
b、 The straight pipe sections before and after the flowmeter are too short, and elbows, valves, and other components that greatly interfere with the flow state of the measured medium are directly installed in front of the flowmeter;
Solution: Install according to the instructions or perform on-site flow calibration on the flowmeter.
c、 Leakage of bypass pipeline;
Solution: Check and replace the bypass pipeline.
d、 There are strip-shaped debris wrapped around the target, which increases the stress on the target;
Handling method: Refer to the previous method for handling miscellaneous items.
4. There are four main reasons why the flowmeter has no indication or signal:
a、 Poor contact or detachment of power supply;
Solution: For flow meters with built-in batteries, check if the battery is securely installed, if the contacts are in good condition, and if the battery is charged. For external power sources,
It should be checked whether the connections between the connecting wires are intact, whether the wires are conductive, and whether the external power supply is normal.
b、 The flow meter circuit is damaged;
Solution: Return to the factory for repair.
c、 The display screen is damaged;
Solution: Return to the factory for replacement.
d、 User signal receiving system malfunction;
Solution: Check and troubleshoot.
5. The reading of the flowmeter remains zero during operation, and the main reasons for this phenomenon are:
a、 The force bearing component (target) falls off, causing the sensor to be unable to sense;
Solution: Assemble target pieces of the same specifications.
b、 The flowmeter sensor has no voltage output signal;
Solution: First, check if the sensor is damaged. The specific method is to check if there are any changes in the sensor data.
c、 The flow rate of the measured medium is too small, lower than the minimum scale flow rate of the flowmeter;
Solution: Return to the factory and replace the load-bearing components.
10、 Parameter Comparison Table:
Model Selection Table
|
model |
caliber |
Intelligent target flowmeter |
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HL-BSL |
10~5000 |
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code |
Instrument Type |
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A* |
Cone tube threaded type |
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|
A |
Pipeline flange type |
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B |
Clamp on type |
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C |
plug-in |
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D |
Online detachable type |
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E |
other |
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|
code |
Media Type |
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Y |
liquid |
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Q |
gas |
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Z |
steam |
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|
code |
medium temperature |
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D |
low temperature(-30℃～-200℃) |
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C |
normal temperature(-20℃～+80℃) |
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Z |
Moderate temperature(+80℃～+200℃) |
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|
G |
high temperature(+200℃～+500℃) |
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nominal pressure |
A：0.6MPa B：1.0MPa C：1.6MPaD：2.5MPa E：4.0MPa F：5.0MPaG：10.0MPa H：15.0MPa I：20.0MPaJ：25.0MPa K：42.0MPa L：2.0MPaM：6.3MPa N：11.0MPa O：16.0MPaP：26.0MPa | ||||||||
|
Compensation form |
P: Pressure compensation |
T: Temperature compensation |
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output form |
N |
No output (built-in lithium battery header display) |
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S |
pulse output |
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R |
Communication output |
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I |
4～20mACurrent output (two-wire system) |
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K |
Alarm switch output |
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G |
GPRSWireless remote transmission |
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Explosion proof structure |
X |
Intrinsically safe type |
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|
Y |
Explosion proof type |
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Shell Material |
T |
carbon steel |
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N |
stainless steel |
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Q |
Special materials |
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Sensor material |
1 |
Hastelloy alloy |
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|
|
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2 |
titanium |
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3 |
304stainless steel |
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4 |
Special materials |
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a、 The specifications of the flowmeter flange shall comply with the relevant technical parameters, technical conditions, and types specified in the GB/T series standards. It can also be processed according to customer requirements;
b、 In the selection of flow meters, users should specify the various requirements of the required flow meter in the format of the model description;
c、 If users need to use calibers, nominal pressures, and output forms other than those specified in this model, please provide explanations;
d、 When selecting a high-temperature flowmeter, in addition to filling in the model description format, the high operating temperature of the tested medium should be specifically indicated;
e、 For flow meters with temperature and pressure compensation, in addition to filling in the model description format, the operating temperature and pressure range that need to be compensated should be specifically stated;
f、 Users need special measurement tube materials, which should be explained.
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