1. Product overview:

LXZ series double rotor flowmeter (hereinafter referred to as flowmeter) is the ideal generation of positive displacement flowmeter in China. It is a new type of positive displacement flowmeter designed with precision machining and assembly. A pair of helical rotors is the moving body in the metering cavity, which plays the role of dividing, measuring, transporting and discharging the liquid to be measured. This type of flowmeter has a positioning gear added to the structure, so that the two rotors do not touch each other when they rotate. The flowmeter operates smoothly, has low noise, less wear, high accuracy, and strong viscosity adaptability. The flowmeter is treated with chemical nickel plating, so it has the characteristics of anti-corrosion and wear resistance, and can replace the flowmeter made of stainless steel.

Second, the structure principle:

1. Principle:

The measurement of the fluid flow of the LXZ series double rotor flowmeter is completed in the metering cavity. A pair of helical rotors rotate under the pressure of the liquid, and the closed space formed between the rotors and the wall of the metering chamber (the shaded part in the figure) discharges 8 times the shaded volume per revolution. Therefore, according to this relationship, as long as the number of rotations of the rotor is measured, the cumulative flow can be calculated, and the instantaneous flow can be measured according to the number of revolutions per second.

2. Structure:

The double rotor is mainly composed of a casing, a pair of helical rotors, a magnetic coupling, a deceleration mechanism, an adjusting gear, a counter and a signaling device. The body of the flowmeter is divided into two types: single body and double body. The single body is the shell and the flowmeter box as a whole; the double body is the shell and the flowmeter are two bodies. The rotational speed of the screw rotor is transmitted to the head counter through a reduction mechanism composed of a magnetic coupling and a series of gears. The magnetic coupling is mainly composed of active magnetic steel and driven magnetic steel. The use of magnetic coupling can improve the working pressure and working temperature of the flowmeter, with safe operation and convenient maintenance.

3. Application occasions:

LXZ series double rotor flowmeter is a precision instrument used for the measurement and control of liquid flow in pipelines. It is widely used in petroleum, chemical, metallurgy, electric power, transportation, ships, oil depots, terminals, tank trucks and other departments, especially for crude oil, refined oil, light hydrocarbons and other industrial liquids. It can be equipped with a transmitter to output electrical pulse signals, which can be transmitted to secondary instruments or computers to form automatic control, automatic detection and data processing systems.

Fourth, the main features:

1. High accuracy, good repeatability, balanced operation, no pulsation and long life;

2. There is no need for straight pipe sections before and after the flowmeter, and the installation space is small;

3. The flow accuracy is not affected by pressure and flow changes, and the performance is stable;

4. It can be equipped with temperature and pressure sensors to compensate the temperature and pressure of the gas;

5. With pulse signal and analog signal, it can realize centralized and real-time management of computer data through RS485 communication interface;

6. Low power consumption, can be powered by internal battery or external power supply;

7. High-resolution dedicated LCD display, intuitive and convenient reading.

Five, technical parameters:

1. Measurable liquid petroleum, petroleum products, chemical medium, etc.;

2. Nominal diameter (mm) 10, 15, 25, 40, 50, 80, 100, 150, 200, 250, 300;

3. Accuracy (%) 0.1, 0.2, 0.5;

4. When the pressure loss is 0.4-3 mPa.s, <40KPa;

5. Working pressure (MPa) 1.6, 2.5, 4.0, 6.3;

6. Temperature range (℃) -20～+60, -20～+120, +100～+200, +150～+250;

7. Protection grade IP65;

8. Ambient temperature (-30～+70℃);

9. Medium viscosity (0.32～1000mPa.smPa.s);

6. Installation requirements:

1. Environmental conditions: no corrosive fluid around, small mechanical vibration, less dust and far away from heat sources. For intelligent flowmeters equipped with volume correctors, there should also be a compliant environment.

2. Ambient temperature: generally within the range of -20-+8O℃.

3. Pipeline conditions: Before installing the flowmeter, the pipeline must be cleaned and purged to remove all debris, rust and dirt. The connecting pipe should generally be coaxial with the inlet and outlet of the flowmeter, and no protrusions protruding from the pipe wall should protrude into the pipe. The flowmeter should be installed without stress, fully considering the pipeline stress caused by the working temperature.

As a new type of positive displacement flowmeter, only if it meets its working conditions and is used correctly according to the requirements, it can take advantage of its ideal cost performance and prolong its service life. Therefore, the following three issues should be paid attention to in the selection and use.

1. Due to the single-shell structure, the maximum pressure is not higher than 2.0MPa, so high-pressure long-distance pipelines should not be used.

2. When it is used again in discontinuous use occasions, the air in the metering chamber must be drained from the exhaust hole to prevent the generation of air pockets, which may lead to the increase of metering errors and the damage of graphite bearings.

3. The rotor clearance is not higher than 0.2μm, and the medium travels in the metering chamber for a long time. The requirement for the purity of the metering medium is higher than that of other positive displacement flowmeters. It is necessary to use a stainless steel filter screen of no less than 40 meshes and clean it regularly. The rotor is made of cast iron, and the moisture content of the medium is required to be no higher than 5%, otherwise it will cause rust and affect the use.