Why need thermal mass flow meter for natural gas measurement?
Thermal mass flow meter fully meets the requirements of natural gas measurement accuracy, and has small size, high reliability, and easy installation and low pressure loss. Ideal for natural gas flow measurement applications.
In practical applications, natural gas (NG) supply pressure can vary greatly, especially for users who set up pressure regulating stations. Generally, the pressure can be set according to the needs, and its application varies greatly. The maximum allowable pressure for industrial users and individual boiler rooms is 0.4MPa, and the different pressures for public buildings and residential users from low-pressure and medium-pressure inlets are 0.005 and 0.2MPa respectively. In such a large pressure range, it is completely possible that the pressure fluctuates between 10% and 90%. At this time, the change of the volume flow meters are not very accurate, some departments have installed temperature and pressure sensors to compensate volumetric natural gas flow metering devices in order to derive standard or normal flow rate (Nm3/h) and then accumulate it to make the measurement more reasonable. Users need to cost more to have temperature sensor, pressure transmitter and natural gas flow totlaizer to calculate the mass flow, even though, with some many instruments involved, the measurement is not very accurate.
For large factories which have large natural gas consumption, the direct mass measurement should be considered.
Natural Gas supply line flow can vary so much, for some velocity flowmeters and differential pressure flowmeters,the turn down ratio is around 1:3 or 1:10, it is difficult to fully measure the change in natural gas consumption and detect low flow natural gas. However thermal mass flow meter has large turndown ratio 100:1 which can fully detect and calculate low flow natural gas and natural gas large flow.
Attentions to thermal mass flow meters for natural gas measurement
In the past few years, thermal gas mass flow meters (TMF) for natural gas have developed very well. Thermal dispersion or immersible mass flow meter is a perfect instrument in natural gas flow measurement. It does not require pressure and temperature correction to measure the natural gas mass flow, a flow sensor can achieve from extremely low natural gas flow to high natural gas flow, and the range ratio can reach more than 1:100. It is suitable for clean and pure gas or mixed gas measurement. Natural gas is a kind of mixed gas which includes ethane, butane, pentane, carbon dioxide, carbon monoxide, hydrogen sulfide, etc.
TMF has moderate measurement accuracy. The basic error of Thermal dispersion flowmeter is usually ±1%FS, and the repeatability is between 0.2%~0.5%FS.
The response time of thermal mass gas flow meter is relatively long, the time constant is generally 2~5 seconds.
Most of the thermal mass flow sensors can be installed in any position (horizontal, vertical or inclined). For some natural gas low flow rates detection, better consult Silver Automation Instruments to have better advice to install in more suitable position to get more accurate low flow natural gas flow measurement.
However, some types of
natural gas mass flow meter instruments are sensitive to the installation posture, and most manufacturers will explain the influence of the installation posture and installation requirements. Most immersion TMF performance is not affected by mounting posture. However, due to the influence of the heat flow of the gas convection in the pipeline during the measurement of low flow velocity, the installation posture is important. Therefore, to obtain accurate measurements when flowing at low and very low flow rates, it is necessary to follow the manufacturer's installation recommendations based on the design of the meter.
The vibration of the pipeline connected to the natural gas thermal mass flow meter will not cause vibration on the NG measurement value, and will not affect the measurement performance of the instrument under normal conditions. Users need to firmly fix the thermal mass flow meter probe to the natural gas pipeline.
Thermal mass flow meter has a long response time and is not suitable for pulsating flow measurement. Measurement errors caused by pulsation usually drive the natural gas NG flow meter output and display high value.
Thermal mass flow meter need to measure dry natural gas, cannot contain moisture. Potential deposits, scaling, and condensation from the natural gas will affect instrument probe performance. Natural gas to be measured by mass flow meter should not be too dirty.
Strong functions for natural gas thermal mass flow meters
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Digital natural gas flow measurement: 4-20mA current signal output, 0-5KHz flow frequency pulse; RS485 communication interface.
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Various process connections: inline or insertion type thermal mass flow meters, flanges or thread connection natural gas flow meters;
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Inline flanged natural gas thermal mass flow meter can be 1/2”,3/4 inch , 1 inch,1.5 inch or 2 inch natural gas thermal mass flow meters;
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Insertion thermal mass flow meter can be used for large pipeline natural gas flow meters, such as 3” thermal mass flow meters, 4 inch, 6” insertion thermal mass flow meters, 8 or 10 inches dial size .,etc.
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Different install position: horizontal or vertical for natural gas flow sensor;
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Very small pressure loss with only tiny sensor probe.
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LCD display to show natural gas flow rate, totalized flow and natural gas temperature information;
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Various natural gas flow units options:g/min,g/s,Kg/min,Kg/h,Nm3/h,Nm3/min,NL/h,NL/min,SCFM, totalized natural gas flow units: g,Kg,Nm3,NL,CFM;
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Low price from SILVER AUTOMATION INSTRUMENTS natural gas mass flow meter, price from $ 800
