ZRN-LZ series metal rotor flow meter for low flow, low Reynolds number flow measurement of the medium, this flow meter with electric remote-site instruction or function, remote output standard 4 ~ 20mA signal. You can configure the limit switch, control and alarm. The instrument has a reasonable structure, easy maintenance, small pressure loss, reliable, wide measuring range of features.
ZRN-LZ series metal rotor flowmeter has local display and intelligent remote type, with the pointer display instantaneous / accumulated flow LCD, upper and lower limit alarm output, accumulated pulse output, batch control, the standard two-wire 4- 20mA current output and other means for the user to provide a very broad choice, in addition to the instrument uses Motorola's advanced micro-processing chips and high-quality industrial assembly center to ensure that the flow meter in a variety of application areas of excellent performance. Over the years, a variety of excellent performance and reliability of the metal rotor flowmeter, and better cost performance, widely praised by the petrochemical, steel, power, metallurgy, light industry, food, pharmaceutical, water treatment and other industries of all ages.
Structure and basic principles
Metal rotameter flow rate detection element is made from a vertically upward under the expanded tapered tube and a movement along the axis of the cone at the group consisting float. Works as shown, the measured fluid from the bottom up 1 After annulus tapered tubes 1 and 2 are formed of 3:00 float float float upper and lower ends are formed to produce a differential pressure rising force, suffered when the float rises immersed in a fluid force is greater than the weight of the float, the float will rise, along with the annulus area increased fluid flow at the annulus immediately drop the float upper and lower ends of differential pressure decreases, the force acting on the float also rises with decreasing until the lifting force equal to the weight of the float is immersed in the fluid, the float will stabilize at a certain height. float In the cone height and flow through the corresponding relation.
Volume flow rate Q of the basic equation is:
When the float non-solid core hollow structure (put weight adjustment), then
Flow coefficient formula α-- meter, because the float shape varies;
ε-- measured fluid is a gas expansion coefficient of the gas, usually due to this factor correction is very small and is ignored, and by check
It has been included in the flow coefficient, such as a liquid then ε = 1;
• F-- circulation of the annular area, m2;
g-- local gravitational acceleration, m / s2;
Vf - Float volume, if extensions should also be included, m3;
ρf - Float material density, kg / m3;
ρ-- measured fluid density, such as gas density float upstream in cross section, kg / m3;
Ff - Cross-sectional area of the float working diameter (maximum diameter) at a, m2;
Gf - Float quality, kg.
Circulation relationship with the annular area between the float height formula (3), when the structural design has been set, then d, β is a constant. Where there is h quadratic, non-linear relationship generally can not ignore this, and only in cone angle is very small, is treated as a linear approximation.
Where d-- float maximum diameter (ie working diameter), m;
h-- float float from the tapered tube diameter equal to the largest diameter of the rising height, m;
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