WK-LLQ Roots (waist wheel) flowmeter

overview

Gas waist wheel flowmeter is a high-precision, high reliability, and wide range gas monitoring and measuring instrument.

The intelligent gas waist wheel flowmeter is a new type of flowmeter that integrates flow, temperature, pressure sensors, and intelligent instruments based on the waist wheel flowmeter.

The intelligent gas waist wheel flowmeter is an ideal instrument for measuring non corrosive gases such as natural gas, city gas, propane, ammonia, and industrial inert gases.

Main features of the product:

●Wide range:

According to different specifications, the maximum range can reach 1:216

●Low initial flow rate:

According to different specifications, the minimum starting flow rate can reach 0 04m3/h.

●High precision and high repeatability:

Long term accuracy is not affected by the medium, and long-term operation ensures stable accuracy.

●Low pressure loss:

According to different specifications, the pressure loss is 0 08kPa-0.58kPa。

●High integration, low power consumption:

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

●Compact structure:

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

●Digital pressure temperature sensor:

The configuration of digital temperature sensors and digital pressure sensors, with separate calibration and verification, is easy to replace, maintain, and use.

●Segmented correction:

According to the flow frequency signal, the instrument coefficient can be automatically linearly corrected in six segments to improve the wide range accuracy of the instrument.

●Complete data storage function:

Using E2PROM data storage chip to save user parameters and manufacturer parameters, with timely data saving function, can prevent data loss in case of sudden power failureIn the event of a power outage, internal parameters can be permanently saved.

●Basic output complete:

The intelligent flowmeter is equipped with a base meter pulse output, a working condition or standard condition pulse signal output, and a calibration pulse output. RS485 interface output, can also be customized according to user needsTo output a 4-20mA standard analog signal.

●Data traceability management:

Real time database, available for query and analysis through RS-485 communication interface.

●GPRS real-time management system:

In this series, the B-type meter has GPRS transmission function, which can be implemented online, timed, and fixed-point, making it extremely easy to set up a GPRS wireless network system.

Structure and Working Principle

The intelligent waist wheel flowmeter consists of 5 parts

1) Gas waist wheel flowmeter

2) Flow sensor

3) Pressure sensor

4) Temperature sensor

5) Intelligent traffic integrator

Figure 1 Schematic diagram of the composition of the intelligent waist wheel flowmeter

Working principle of intelligent gas waist wheel flowmeter

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 roomUnder the action of the pressure difference between the inlet and outlet of the circulating gas (P in>P out), the rotor is maintained in the correct relative position through precision machined tuning gears. Between rotors, rotorsMaintaining optimal working clearance between the shell, rotor, and wall panel achieves continuous non-contact sealing. For every revolution of the rotor, four times the effective volume of the measuring chamber is outputThe gas. The measurement process and working principle are shown in Figure 1 (only a quarter cycle is shown in the figure).

Working principle of intelligent flow integrator

The intelligent flow integrator consists of temperature and pressure detection, flow sensors, and microprocessor units. In the intelligent traffic integratorThe microprocessor 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: absolute temperature of the medium (273.15+t) (K);t: Temperature of the measured medium ("C");

Zn: compressibility coefficient under standard conditions;Zg: Compression coefficient under working conditions; .

Tn: Absolute temperature under standard conditions (273.15+20) (K); Pn: Standard atmospheric pressure (101.325 kPa).

Note: Natural gas Zn/Kg=Fz2, where Fz is referred to as the over compression factor, according to the standard SY/T6143 of China National Petroleum Corporation-Calculate using the formula from 1996.

Main technical parameters and functions:

Product Execution Label

This flowmeter complies with JB/T 7385-1994 "Gas waist wheel flowmeter" and JJG633-2005 "Calibration of gas volumetric flowmeter"The metrological technical specifications and standards of the regulations comply with the national standard GB3836.1-2010 "Explosive Atmosphere Part 1: Equipment Communication"According to the "Requirements" and GB3836.4-2010 "Explosive Atmosphere Part 4: Equipment Protected by Intrinsic Safety" standards

Accuracy level:

1.0 level: Qmax-0.2Qmax soil 1.0% 0.2 Qmax Qmin soil 2.0%

Level 1.5: Qmax-0.2QmaxShi 1.5%0.2 Qmax Qmin ± 3.0%

Unless otherwise specified, the product is manufactured with a precision level of 1.5. For other accuracies, special instructions are required for customization when ordering.

Specifications, basic parameters, and performance indicators of flow meters (see Table 1)

(Table 1)

Conditions of Use

Standard condition: P=101.325 kPa T=293.15K

Usage conditions: a. Environmental temperature: -25C~+80C

b. Medium temperature: -20C~+60C

c. Relative humidity: 5%~95%

d. Atmospheric pressure: 86KPa~106Kpa

Electrical performance indicators:

Working power supply: a. Internal power supply: 1 3.6VDC lithium battery, which can work normally when the battery voltage is between 3.1V and 3.6V. When the voltage is below 3.1V, the battery should be replaced.

b. External power supply: ± 24VDC+15%, ripple ≤ ± 5%, suitable for 4-20mA output, pulse output, RS-485, etc;

Power consumption of the whole machine: external power supply,<1W internal power supply, average power consumption ≤ 1mW, can work continuously for more than five years.

Pulse output mode under working conditions

a. The working condition pulse signal is directly output by isolating and amplifying the working condition pulse signal detected by the flow sensor through optocoupler. The high level is ≥ 20V and the low level is ≌ 1V. This pulse is mainly used for instrument calibration.

b. The frequency signal proportional to the standard volume flow rate is isolated and amplified by an optocoupler, with a high level of ≥ 20V and a low level of ≤ 1V.

c. Calibration pulse signal, output amplitude of 0-3V, output pulse width of 500ms. This pulse is mainly used for IC card control devices or other equipment for urban gas metering. The signal outputs one pulse per 1m3.

Current output:

The 4-20mA standard analog current output function is proportional to the standard volumetric flow rate, with 4mA corresponding to 0 Nm3/h and 20mA corresponding to the maximum standard volumetric flow rate (which can be set). Output format: 2-wire or 3-wire system

RS485 communication

It can be connected to personal computers and PLCs through the built-in RS485 standard interface for serial communication. It can display medium pressure, temperature, instantaneous flow rate, cumulative standard flow rate, battery voltage, etc.

GPRS communication

Serial communication is carried out through the built-in GPRS system. The remote meter reading system can display medium pressure, temperature, instantaneous flow rate, cumulative standard flow rate, battery voltage, etc.

Valve control output:

Can choose valve control type, directly control the valve, achieve independent control and remote control