The OBLQ gas rotameter is an instrument for precisely measuring gas flow. Based on the volumetric measurement principle, it is used to accurately measure the gas flow passing through a closed pipeline.
The flowmeter consists of a rotameter sensor and a display unit. It can be used to measure non-corrosive gases such as natural gas, urban gas, propane, nitrogen, and industrial gases. It is mainly applied in gas commercial settlement in industries like restaurants and hotels, gas metering in distri-bution networks, gas metering at gas pressure regulating stations, gas metering in industrial and civilian boilers, and can also be used as a standard flow-meter.

Main features

·Long working life, high accuracy and good repeatability. The internal rotor is precision machined and balanced, rotates without contact, and has good bearing lubrication to ensure that the flow meter remains accurate and has a long working life;
·The initial flow rate is small, the range is wide, and the pressure loss is small;
·There is no need for straight pipe sections before and after the flowmeter, the measurement accuracy is not affected by pressure and flow changes, and it can be installed in narrow environments;
·Good versatility, all specifications of Roots flow sensors can use universal display;
· Equipped with an RS485 communication interface and a dedicated signal concentrator, it can form a remote data collection and monitoring system through GPRS and the Internet to facilitate centralized collection and real-time management of data;
· Built-in protection circuits such as lightning protection, surge protection, and pulse group suppression, and the external output interfaces are electrically isolated, with strong anti-interference and good reliability;
·The wireless communication module can be embedded, and multiple working modes can be configured and selected. The GPRS module can be powered by the built-in battery to achieve a limited number of data transmissions, making it easy to use;
·Temperature and pressure can be set to acquisition and non-acquisition modes according to actual conditions. The time interval for temperature and pressure acquisition can be set. In non-acquisition mode, the internal temperature and pressure setting value can be taken;
·In the case of temperature and pressure failure, use alternative temperature values and alternative pressure values for calculation to avoid large-scale deviations in the accumulation amount, and you can view the error standard condition accumulation amount and error working condition accumulation amount in the case of failure;
·Adopt high-precision digital temperature sensor and digital pressure sensor, and the digital pressure sensor has its own temperature correction function, high pressure detection accuracy, good long-term stability; anti-strong magnetic interference, anti-interference and anti-theft gas;
·It has real-time detection and correction of the open and closed status of the instrument, and has parameters to modify the operating status, and stores events and time;
·Has data tamper-proof function and automatically records key data modifications;
·Has real-time data storage function, which can prevent data loss when replacing the battery or sudden power failure. In the power outage state, the internal parameters can be permanently saved;
·The instrument has explosion-proof function, the explosion-proof mark is ExiallCT4Ga, and can work in hazardous areas Zone 0, Zone 1 and Zone 2;
·Flowmeter housing: Protection grade is IP65.
This product is designed and produced as intrinsically safe explosion-proof. It has been inspected by the National Explosion-proof Electrical Products Quality Inspection Center and complies with the relevant provisions of national standards GB3836.1-2021 and GB3836.4-2021.

Structure and working principle

Structure

The flowmeter consists of two parts: a Roots flow sensor and a display instrument, as shown in the figure.

The working principle of gas Roots flowmeters

The gas Roots flowmeter is a volumetric flow meter. When the gas passes through the flowmeter as shown in the figure below, the pressure difference generated between the inlet and the outlet acts on a pair of waist wheels connected with high-precision synchronous gears, thereby driving the waist wheels to rotate. During this period, the metering chamber, a closed space formed between the waist wheel, the inner wall of the housing and the gland, is periodically inflated and exhausted. The rotation speed of the waist wheel is proportional to the volume of gas passing through the flow meter. The rotation of the waist wheel is transmitted to a mechanical counter or outputs a flow pulse signal through a magnetic coupler, thereby accumulating the volume flowing through the metering chamber to achieve the purpose of measurement.

Technical performance indicators

·Product execution standard
This flowmeter complies with the JB/T 7385-2015 "Gas Rotary Flowmeter" industry standard and JJG 633-2005 "Gas Volumetric Flowmeter" calibration procedures. Comply with the relevant parts of GB3836.1-2021 "Explosive Environment Part 1: General Requirements for Equipment" and GB 3836.4-2021 "Explosive Environment Part 4: Equipment Protected by Intrinsically Safe "i"" standards.
·Accuracy grade
The accuracy levels within the measuring range are: Level 1.0 and Level 1.5. Level 1.0: Qt~Qmax is ±1.0%, Qmin~Qt is ±2.0%; Level 1.5: Qt~Qmax is ±1.5%, Qmin~Qt is ±3.0%, where Qt=0.2Q-max.
·Technical parameters