ZY-LLQ Roots flowmeter (also known as waist wheel flowmeter) is a new generation flowmeter that integrates flow, temperature, and pressure detection functions, and can automatically compensate for temperature and pressure. Gas is a compressible fluid, and its volume value is closely related to temperature and pressure. In order to unify the standards of both trading parties, it is necessary to convert the actual volume into the standard volume under reference conditions (101.325 kPa 20 ℃). To achieve this goal, an intelligent gas waist wheel flowmeter can accurately correct the volume of gas. It is an ideal instrument for gas measurement in industries such as petroleum, chemical, power, and metallurgy.

The flowmeter consists of 5 parts

1. Flow sensor

2. Pressure sensor

3. Temperature sensor

4. Gas waist wheel flowmeter (mechanical)

5. Intelligent traffic integrator

The working principle of Roots flowmeter (see Figure 2) a

The intelligent gas waist wheel flowmeter is mainly composed of components such as a housing, a conjugate rotor, and an intelligent flow integrator. A pair of conjugate rotors installed in the measuring room maintain the correct relative position of the rotors through machined calibration gears under the action of the pressure difference (P in>P out) at the inlet and outlet of the circulating gas. Continuous non-contact sealing is achieved by maintaining working clearances between rotors, rotors and shells, and rotors and wall panels. Every time the rotor rotates, it outputs four times the effective volume of the measuring chamber gas. The number of revolutions of the rotor is transmitted to the intelligent flow accumulator through a magnetic sealed coupling device and a reduction mechanism, thereby displaying the cumulative volume of the output gas. The measurement process and working principle are shown in Figure 1 (only a quarter cycle is shown in the figure).

position 1 position Position 2, Position 3, Position 4

Figure 2 Working principle of gas waist wheel flowmeter

The working principle of the intelligent flow integrator (see Figure 3)

The intelligent flow integrator consists of temperature and pressure detection simulation channels, flow sensor channels, and microprocessor units, and is equipped with an external signal interface to output various signals. The microprocessor in the intelligent flow integrator compensates for temperature and pressure according to the gas equation, and corrects the compression factor. The gas equation is as follows:

(1)

In the formula:

Qn： Volume flow rate under standard conditions (m3/h);

Qg: Volume flow rate under operating conditions (m3/h);

Pg： Gauge pressure at the pressure detection point of the flowmeter (kPa);

Pa： Local atmospheric pressure (kPa);

Tg： Temperature of the medium (273.15+t) (K);

t： Temperature of the measured medium (℃);

Zn： Compression coefficient under standard conditions;

Zg： Compression coefficient under working conditions;

Tn： Temperature under standard conditions (273.15+20) (K);

Pn： Standard atmospheric pressure (101.325 kPa);

P: P=Pa+Pg.

Note: For natural gas Zn/Zg=Fz2, Fz is referred to as the over compression factor. This product is calculated according to the formula in the standard SY/T6143-1996 of China National Petroleum Corporation.

• Adopting advanced microcomputer technology and high-performance integrated chips, the whole machine has powerful functions and superior performance

• The circuit adopts surface mounting technology, with a compact structure, strong anti-interference ability, and high reliability.

• Integrating high-precision temperature, pressure, and flow sensors with intelligent volume correction, it can detect the temperature, pressure, and flow of the measured gas, and perform automatic flow tracking compensation and compression factor correction calculations.

• Pressure sensors, temperature sensors, and flow sensors are all built-in, making the structure more compact.

• Adopting advanced low-power high-tech, the whole machine has low power consumption, and can operate on long-term power supply from the built-in battery or external power supply.

• According to the flow frequency signal, the instrument coefficient can be automatically linearly corrected in six segments, thereby improving the accuracy of instrument use.

• It has fault self diagnosis and alarm functions, high reliability, LCD display, clear and intuitive, and convenient reading.

• The flowmeter is equipped with pulse signal output and can also output 4-20mA standard analog signal according to user needs.

• The instrument comes with a real-time database and can be paired with our factory's dedicated MODEM through RS-485 communication interface to form a telephone meter reading network, facilitating centralized data collection and real-time management.

• Adopting advanced low-power technology, the whole machine has low power consumption and can run for more than five years using the built-in battery.

• On site display of flow values and multiple signal output functions can meet the needs of different sites and systems.

• Using E2PROM data storage chip to store user parameters, manufacturer parameters, and certain historical records.

• Adopting a high contrast three row LCD display, it can display date, standard cumulative flow rate, standard instantaneous flow rate, medium temperature, pressure value, and battery voltage.

• It has real-time data storage function, which can prevent data loss during battery replacement or sudden power failure. In the event of a power outage, internal parameters can be saved.