LGQ-Mini Gas Roots Flowmeter

Overview

The LGQ-Mini gas rotary meter is a new generation of high-precision and highly reliableprecision metering instrument that integrates temperature, pressure (only for intelligenttype) flow sensors and intelligent flow accumulation instrument. It is designed inaccordance with international standards and developed by combining advancedtechnologies of flow meters at home and abroad. With multiple patented technologies, itsoutstanding low-pressure and high-pressure metering performance, multiple signal outputmethods, and low sensitivity to fluid disturbance make the gas rotary (Roots) flowmeteran especially excellent commercial trade metering instrument for accurately measuringgas flow and cumulative total volume.

Application fields

This series of gas Roots flowmeters are widely used in: urban pipeline gas metering,industrial gas metering, gas pressure regulating station metering, energy management,and various other occasions for metering or flow control of non-corrosive gases.

Working principle

The intelligent gas waist wheel (rotary) flowmeter mainly consists of a housing, a pair of conjugaterotors, a counter and an intelligent flow accumulation meter. The pair of conjugate rotors installedin the metering chamber rotate under the pressure difference (P_in >P_out) between the gas inletand outlet.The precisely machined calibration gears keep the rotors in the correct relative position.The rotors, the housing and the side plates maintain the optimal working clearance, achievingcontinuous non-contact sealing. For each rotation of the rotors, four times the effective volume ofthe metering chamber of gas is output. The number of rotations of the rotors is transmitted to theintelligent flow accumulation meter through the magnetic seal coupling device and the reductionmechanism, thereby displaying the cumulative volume of the output gas. The metering process andworking principle are shown in Figure 1(only a quarter cycle is shown in the figure).

Product Features

Various patentable structural forms

1) Single-display intelligent type: Equipped with temperature and pressure sensors, it features temperature and pressure tracking compensation functions, directly converting the working condition flow rate to the volume flow rate under standard conditions, while simultaneously displaying the working condition flow rate and cumulative flow rate.

2) Mechanical type: It directly displays the working condition flow through mechanical digit wheels.

3) The dual-display intelligent type is equipped with temperature and pressure sensors, featuring temperature and pressure tracking compensation functions. It directly converts the working condition flow rate to the volume flow rate under standard conditions, and simultaneously displays the working condition flow rate and cumulative flow rate. It also directly shows the working condition flow rate through mechanical digit wheels to prevent losses due to electronic display failures. The structural forms include separate displays at both ends and a single display in one meter housing.

It can self-diagnose faults of pressure and temperature sensors.

(Only for intelligent type), and directly displayed on the LED screen. When the pressure or temperature sensor malfunctions and shows "OPEN", the flowmeter will automatically enter pressure or temperature correction operation according to the agreed pressure or temperature value mode to ensure that the interests of both parties are not damaged. It has a unique function of displaying and recording the upper limit of working condition flow and the upper limit of operating pressure (Error), which is convenient for understanding the actual usage of the medium. The flowmeter can be rotated 90 degrees for positioning, making it easier and more direct to read the meter under various installation conditions.

It has a unique time display and real-time data storage function, and is equipped with a powerful and user-friendly data management software system that can print various automatically generated charts.

Working Principle of Intelligent Flow Accumulator

The intelligent flow totalizer is composed of temperature and pressure detection analog channels, flow sensor channels,and a microprocessor unit, and is equipped with external signal interfaces to output various signals. The microprocessor in the intelligent flow totalizer performs temperature and pressure compensation according to the gas equation and makes corrections for the compression factor. The gas equation is as follows:

In the formula:

Volume at standard state (m³):

V: Volume under normal conditions (m³)

Pg: Gauge pressure (Kpa) at the pressure detection point of the flowmeter Local atmospheric pressure (Kpa)

Tg:Glass transition temperature of the medium (273.15 + t) (K)

t: Temperature of the medium under test ("C)

Zs: Compressibility factor under standard conditions; Zg: Compressibility coefficient

under working conditions; Ts: Absolute temperature under standard conditions(273. 15 + 20) (K); Ps: Standard atmospheric pressure (101.325 kPa)

The structure of the flowmeter

Based on the principle of electromagnetic induction, the Wiegand sensor is used to sense the pulse signals thatare proportional to the volume flow rate from the alternately magnetized magnetic steel installed on the synchronously rotating gear. After amplification, filtering and shaping, this signal, along with the signals fromthe temperature and pressure sensors, is sent to the microprocessing unit of the intelligent flow accumulation meter for calculation and processing. The volume flow rate and total volume of the gas are directly displayedon the LCD screen.

Standard product range

The flow rate range listed in the table is the flow rate range at the time of factory calibrationof the product (at normal temperature and pressure, with FA medium being air, p=1.205kg/m³):