HSVT3000 Type

Gas flow meter is a dedicated meter, used to measure the volume of fuel gases such as natural gas and liquefied gas. Gas flow meter is used in civil, commercial and industrial buildings that consume fuel gas supplied by a gas station.

Gas flow meter is a dedicated meter, used to measure the volume of fuel gases such as natural gas and liquefied gas. Gas flow meter is used in civil, commercial and industrial buildings that consume fuel gas supplied by a gas station.

Gas is much more difficult to measure than liquids, as the measured volume is strongly influenced by temperature and pressure. The gas flow meter measures a specified volume, regardless of the quantity or pressure quality of the gas flowing through the meter.

There are different designs of gas meters in common use, depending on the gas flow rate to be measured, the predicted flow range, the type of gas being measured and other factors.

Gas flow unit

The gas can compress and change volume when:

  • Under pressure
  • Heat
  • Algefacient

In other words, gas volume at a set pressure and temperature condition is not equal to the same gas volume under different pressure or temperature conditions. Because of this one, the flow rate of the meter refers to the actual flow rate and conventional standard units such as:

  • acm / h (actual cubic meter / hour)
  • kscm / h (standard cubic kilo / hour)
  • LFM (Linear Feet per Minute)
  • MSCFD (Million standard cubic feet per day)

The gas flow rate can be measured directly, irrespective of the effects of pressure and temperature, with a thermal mass flow meter, a Coriolis mass flow meter or a mass flow meter.

Principle of Gas flow meter

Gases are usually measured by their volume, i.e. the flow rate will be expressed as the ratio of the volume of the gas flow per unit time. Hence, the units for measuring air flow are m3 / hour, Nm3 / hour, etc….A more important factor should be noticed while measuring gas flow is the fact that the gas is compressed (unlike a liquid). Thus, their volumes vary with pressure (and temperature as well). To take the indicator into account, values obtained by measuring gases at initial conditions are converted to either the normal temperature and pressure (NTP) basis or the standard temperature and pressure basis. (STP).

Operation of gas flow meter

The flow rate is the actual volume of the gas transmitting through the meter per unit time. Its units are usually in standard liter form per minute; or standard cubic centimeters per minute in SI unit.

Type of Gas flow meter

Just like liquids, gas flow meters appeared in many varieties. Each type is based on a different physical characteristics to infer the gas flow. Depending on the measurement application, these flow meters have different advantages and disadvantages.

Let’s take a quick look at some of the most common, and widely used in industry.

  1. Membrane-type Gas flow meter

    This may be considered as a type of common gas flow meter Found in many applications both in civil and industrial commerce.

    They are composed of 2 or more chambers containing the inner membrane. When there is a flow of gas, the chambers transfer the gas through the membrane continuously. Under pressure, the membrane will shrink or stretch. They act on a connecting shaft structure, causing the shafts to rotate with the gas flow. These spindles have a counter mechanism that counts the amount of gas transmitting through the meter.

  2. Rotating-type Gas flow meter

    Rotating-type Gas flow meter are accuracy equipment that are highly technically engineered. They are capable of handling higher volumes and pressures than Membrane-type Gas flow meter.

    In the flow meter, two impellers of an 8 shape rotate in the correct direction. With each turn, they move a specific amount of gas across the meter. The crankshaft’s rotation acts as the main flow element and can generate electrical pulses for the flow computer or can control the counter like a odometer.

  3. Turbine-type Gas flow meter

    Turbine-type Gas flow meter calculated the gas volume by determining the speed at which the gas travels through the meter. Since the gas volume is inferred by the flow, it is important that the flow be good. The inside small turbine measures the speed of the gas, which is mechanically transmitted to a mechanical or electronic counter.

    This type of turbine gas flow meter does not interfere with air flow, but is limited to low flow rate measurements only.

  4. Ejector-type Gas flow meter

    An Ejector-type Gas flow meter consists of a long, straight pipe with a hole plate to create a voltage drop, affecting the flow.

    This is a type of differential meter, all of which infer the airflow rate by measuring the pressure difference across a flow disturbance by the ejector. The static pressure, density, viscosity, and temperature of the gas must be measured or know the differential pressure for the meter to measure accurately. These flow meters are commonly used in industry because they feature no moving parts. However, they are only used for small, low-range applications.

  5. Ultrasonic-type Gas flow meter

    The Ultrasonic-type Gas flow meter are more complicated than purely mechanical meters. Because they require the ability to process signals and compute data.

    The Ultrasonic-type Gas flow meter measures the speed of gas movement by measuring the speed at which sound travels in the gas environment in the pipeline.

    Ultrasonic-type Gas flow meter

    Ultrasonic-type Gas flow meters are expensive and work best when there is no liquid in the gas being measured, so they are mainly used in high pressure, high flow applications such as Gas pipeline measuring station where the gas is always dry. The output accuracy ratio of the Ultrasonic-type Gas flow meter is probably the largest of any natural gas flow meter. And the range of Ultrasonic-type Gas flow meter is actually larger than that of Turbine-type Gas flow meter.

     

  6. Coriolis-type Gas flow meter

    Coriolis type gas flow meters are usually one or more tubes of longitudinal or axial cross-section that are activated to vibrate at resonance frequencies. This meter type works with liquids and gases. When the fluid in the displacement is at rest, both the upstream and downstream parts of the displacement vibrate in phase.

    The frequency of this vibration is determined by the overall density of the pipe. This allows the gas flow density meter to be measured in real time.

    However, when the liquid begins to flow, the Coriolis force comes into play. This effect describes the relationship between phase displacement in vibration of the upstream and downstream and the flow rate of the fluid contained in the pipeline.

    Coriolis-type Gas flow meter can handle a wide variety of flow rates and are capable of generating volume flow rates – this offers the highest accuracy of flow measurements. Because of the characteristics of the flow density measurement, the Coriolis-type Gas flow meter is also able to deduce the gas flow rate under the flow condition.

Main Specifications/ Special Features:

  • Structure: sensor and probe, together with LCD display
  • No pressure loss due to no internal moving parts.
  • Anti-corrosion, anti-wear.
  • High accuracy.
  • Stable performance, high anti-vibration level.
  • Operates according to Faraday’s law of electromagnetic induction.
  • Can be used to accurately measure the flow rate of conductive, highly corrosive and chemical fluids.
  • Widely used in petroleum, chemical engineering, pharmacy, papermaking, electrical energy and environmental protection industries.
  • Explosion Prevention Standard: ExdIIBT4.
  • Size: DN10 to DN500
  • Standard pressure: 1.0Mpa to 40mPa
  • Accuracy: ± 0.5 to 1.0%
  • Power supply: 85 to 250V AC (45 to 63Hz) and 16 to 36V DC
  • Output current: 0 to 10 or 4 to 20mA
  • Output frequency: 0 to 5,000Hz with photoelectric isolation
  • Pulse output: 0.001 to 1,000m 3/cp, 0.001 to 1,000L/cp, 0.001 to 1,000USG / cp and 0.001 to 1,000 UKG/cp
  • Alarm output (with photoelectric isolation)
  • Upper Alarm: ALMH
  • Lower alarm: ALML
  • Communication: 4-20mA RS485 (Modbus)
  • Operating conditions: Ambient temperature: -10 to 60 ° C
  • Relative humidity: ≤85% RH
  • Atmospheric pressure: 86 to 106kPa
  • Applicable liquid: conductive liquid
  • Liquid temperature: -25 to 65 and 140°C
  • Conductivity: 5μs/cm

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