Capacitive target flowmeter

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ZW - BSL seriesCapacitive target flowmeterIs on the basis of the traditional target flowmeter, with …

Products overview:
ZW - BSL seriesCapacitive target flowmeterIs on the basis of the traditional target flowmeter, with the development of new sensors, microelectronics technology research and development into a new type of capacitance induction flowmeter, it has both orifice plate, vortex flowmeter is the characteristics of the moving parts, and also has the very high sensitivity and accuracy of the comparable to those of volumetric flowmeter, span a wide range.Adopts chip level capacitive force sensor, the highly effective resistance to overload structure design is the new product realize high precision, high stability, the key to the core, combined with its unique anti-interference, impurity resistance, in addition to substitute for the conventional flow measurement can measure flow problems, especially in high viscosity, smudgy medium, easy setting wall, high temperature, low temperature, strong corrosion and other flow measurement has the very good adaptability in difficult conditions.
Second,Structure and working principle:

1, structure,

ZW - BSL series capacitive target flowmeter is mainly composed of measuring tube (shell), new sensors (including choke element), integrating display and output parts.According to the different medium and condition, must choose appropriate sensors, therefore, provide accurate object and parameter measurement, and manufacturers to choose appropriate sensor is the key of the products can be accurate measurement.

2, working principle

When medium in the measurement of pipe flow, because of its kinetic energy and target plate pressure difference, and produce on the target plate force, make the target board of trace amounts of displacement, the force is proportional to the square of the velocity with the media, the size of the target plate force of the target bar transfer, make the sensor elastomer produces trace changes, thereby breaking patches of capacitance bridge balance.Generation and corresponding voltage signal flow force on the target board: by the fluid flow characteristics, the influence of flow rate and is proportional to the square of the voltage produced by the bridge.Its mathematical expression is as follows:

CdA rho/V2 / F = 2

Type: F choke a force (kg) of

Drag coefficient Cd object

A choke pieces on the measuring tube axial projection area (was)

Rho conditions of medium density (kg/m3)

V medium in the measuring tube average flow velocity (m/s)

Choke (target) accept force F, the rigid connection of transfer (rod) to the sensor, the sensor produces voltage signal output: V = KF

Type: V - sensor output voltage (mV), K - proportionality constant, F - choke piece (target) by force (kg),

The voltage signal after preamplifier, AD conversion and computer treatment, obtains the corresponding instantaneous flow and cumulative total.

Applications:

ZW series - BSL capacitive target flowmeter has been widely used in semi water gas, coke oven gas, heavy oil, residual oil metering, asphalt, liquid paraffin, toluene, sulfuric acid, natural gas, flue gas, sewage, water, etc, and other special medium measurement.
Four, the main features:
1, the sensor is no moving parts, simple structure and firm;
2, scope of application and adaptability is wide, the fluid medium in the process of general industrial, including liquid, gas and steam, diameter range (DN15) above, all kinds of working condition (high and low temperature, atmospheric pressure and high pressure) can be used, can say its application scope can be compared with the orifice meter.
3, high accuracy, measurement can reach 0.2% total R;
4, wide range of degrees, 4:1 ~ 15:1 to spake;
5, can solve the difficult problem of flow measurement, such as measuring containing impurities (particles) smudgy fluid;Crude oil, water, high temperature residue, grout, caustic soda, asphalt, etc.
6, high sensitivity, can measure small flow rate, flow velocity can be as low as 0.08 m/s;
7, for small diameter (DN15 ~ (), low Reynolds number (Red = 103 ~ 5 x 103) of the fluid, it can make up for the standard throttle device is difficult to application occasions, such as small steam flow measurement, etc.;
8, can adapt to high parameter measurement of fluid, pressure up to tens of MPa, temperature of 450 ℃;
9, can be used in the measurement of two-way flow of fluid;
10, low pressure loss, which is about half of the standard orifice plate;
11, choke a upstream disturbance resistance is strong, straight pipe upstream side length to 5 ~ 10 d;
12, can take dry (hung heavy method) calibration, bring convenience to users cycle check;
13, direct reading instrument without external energy, clear and easy to operate, can output standard signal (pulse frequency or current signal);
14, meter high cost performance, economical flowmeter;
15, simple and convenient installation, easy maintenance.
Five, the technical parameters:
1, the measurement range of 0-400 t/h;
2, precision grade: 0.5% FS 1.0% FS 2.0% FS.
3, the output signal: 4 ~ 20 ma two wire output and flow into a linear relationship;
4, power supply voltage: 12 ~ 36 VDC;
5, nominal pressure: 1.6 2.5 4.0 6.4 MPa;
6, environment temperature: - 30 ℃ ~ 60 ℃ (special: - 40 ℃ ~ 80 ℃).
7, medium temperature: regular 100 ℃ or less (no heat sink);
Type of high temperature of 400 ℃ or less (with heat sink);
8, liquid material: room for carbon steel or 1 cr18i9ti;The rest are 1 cr18ni9ti;
9, shell material: aluminum;
10, flange standard: DIN2501 special type chosen by the user;
11, cable interface: M20 * 1.5 (internal thread);
12, protection grade: IP65;
13, load characteristic: zui big load resistance (supply voltage - 12) = = 50 * 600 Ω @ 24 v;
14, alarm output, the form of open collector, zui big input current 100 ma, zui big switch voltage 30 VDC, with belt deviation control;
Pulse output: 15, zui small pulse width 50 ms, dual output;
16, zui large cumulative flow display value of 50000 units, automatic reset;
17, damping time: 1 ~ 100 seconds arbitrary adjustable.
18, explosion-proof, explosion-proof, explosion-proof certificate number. 
Six, install and use notice:
(1) the installation considerations
1, measurement before and after the pipe should be straight pipe, the pipe diameter of straight pipe shall be the flowmeter measurement tube diameter is equal, such as pipe diameter with different pipe diameter same reducer connected to the entrance.Meter length of straight pipe upstream side is generally not less than 6 ~ 20 d, according to different upstream choke typing, downstream straight pipe not less than 3-4 d.Is according to the horizontal position calibration, the flowmeter is generally installed in horizontal pipe is used, when must be installed in vertical pipe, must use weighing method for flow meter vertical install state calibrated, direction of flow shall be from bottom to top.
2, for ease of use and maintenance to prevent flowmeter enabled one-way bearing, downstream of the bypass pipe flow meter installed in parallel the installation of a drain pipe, easy cleaning and scavenging for instrument, for measuring smudgy fluid or easy to solidification and crystallization medium more necessary.Target plate and the measuring tube (table) should coaxial installation, according to a certain diameter of the experiment proved that the target plate and pipe center if deviation from 1 mm up and down, can result in a 1% to 2% of the flow coefficient of deviation, but around 1 mm deviation, the effect is obvious;
3, install, explosion-proof target type flow time, should pay attention to check for explosion-proof marks and explosion-proof certification, explosion-proof equipment are in good condition.
4, for small diameter flowmeter, due to the small diameter flowmeter is relatively heavy, in order to prevent the pipe deformation or vibrate at work, should be on the brace flowmeter.For large diameter flowmeter can not setting up support.
(2) use matters needing attention
1, before the fluid flow, downstream of the valve should be closed flowmeter, open the upstream of the valve, let the fluid into the meter section.Then slowly open the downstream of the flow meter, valve closed bypass valve at the same time, make the fluid increase slowly, avoid by all means is suddenly opened the valve impact target board damage the instrument.
2, flowmeter after running for a long time, in addition to the target plate, measuring pipe cleaning fouling, hanging heavy method should be adopted to check if there is a change characteristics of the power converter.Hanging method is applied in the center of the target plate is the same as the flow direction of Jordan farmar gravity, adjust instrument, corresponding to the flow force of the upper limit of the flow meter, which according to the type (16.6) to calculate F a, other traffic point are related to weight, read the output signal, check the basic error of each point and linearity."Hung heavy method" in the factory the product specification or other materials' is described, also can see. 
3, fluid force acting on the target board and the function of the hanging heavy force or have difference, so hang heavy method can not completely replace real flow calibration.To obtain high accuracy, the necessary of real flow calibration is needed.
4, when copying or restructured board, attention should be paid to the machining precision of target board, otherwise will affect the flow coefficient.Experimental data show that for target flowmeter mouth = 0.8, pipe diameter DN = 25 mm, if target 0 01 mm diameter deviation, flow coefficient is 1%.Target plate machining accuracy and surface roughness also have influence on the discharge 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.

Nine, parameter table: