Precautions for the use of steam flow meters

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This post was last edited by tiandiyi*an on 2018-5-9 at 16:47. If there is a valve installed near the upstream side of the steam flow meter sensor, constantly opening and closing this valve has a significant impact on the sensor’s service life, and it can easily cause permanent damage to the sensor. It is advisable to avoid installing sensors in very long overhead pipelines, as over time the sagging of the sensor can lead to leakage at the seal between the sensor and the flange. If installation is necessary, pipe fastening devices must be installed 2D distances upstream and downstream of the sensor. 　　The following describes the straight pipe sections at the inlet and outlet of the steam flow meter: To ensure full functionality, the flow pattern at the inlet must not be disturbed. The length of the upstream straight pipe section should be approximately 15 times the diameter (D) of the flow meter, while the length of the downstream straight pipe section should be approximately 5 times the diameter (D) of the flow meter. To ensure that the instrument meets its accuracy specifications under changing process conditions. 　　Note: If your application cannot provide a sufficient length of straight pipe upstream, we will provide you with a solution to ensure that the instrument meets your accuracy requirements, using a straight pipe section of at least 10D upstream. 　　When the measured pressure and temperature signals need to be used to compensate for mass flow or standard flow, install pressure and temperature transmitters downstream of the gas flow meter. 　　Requirements for straight pipe sections in the installation of steam flow meters: Proper selection of the installation location and correct installation of the flow meter are both very important aspects. Errors during installation can, in mild cases, affect the measurement accuracy; in more severe cases, they can impact the flow meter’s service life or even damage it. Its detailed requirements are as follows: If there is a reducer upstream of the installation point, there should be a straight pipe section with an equal diameter of at least 15D (where D is the pipe diameter) upstream, and a straight pipe section with an equal diameter of at least 5D downstream. 　　If there is an expansion tube upstream of the installation point, there should be a straight section with a diameter equal to that of the pipe of at least 18D (where D is the pipe diameter) upstream, and a straight section of at least 5D in diameter downstream. If there is a 90° elbow or a downward connector upstream of the installation point, there should be a straight section with a diameter equal to that of the pipe of at least 20D upstream, and a straight section of at least 5D in diameter downstream. 　　If there is a 90° elbow on the same plane upstream of the installation point, the flow control valve or pressure control valve should be installed as far downstream as possible, at a distance of 5D from the steam flow meter. If installation upstream of the flow meter is necessary, and there are piston or plunger pumps, piston or Roots blowers/compressors upstream of the steam flow meter, then there must be a straight pipe section of at least 25D in diameter upstream, and a straight pipe section of at least 5D in diameter downstream. 　　Special note: If a valve is installed at a short distance upstream of the steam flow meter installation point, constantly opening and closing this valve has a severe impact on the meter’s service life, and can very easily cause permanent damage to it. Try to avoid installing it on extremely long, overhead pipelines, as over time the downward sag of the flow meter can easily lead to leakage at the seal between the flow meter and the flange. If installation is unavoidable, pipe fastening devices must be installed 2D distances upstream and downstream of the flow meter.