![]() ![]() To a specific pure process gas or to the actual components of a mixed gas in use. ![]() There are two methods used in calibrating gas flowmeters, as follows:The direct method, where the meter is calibrated In measuring flow accurately, second only to selecting the proper flow sensing technique is the method of calibration. This informationĬan be used to measure the gas mass flowrate without the need for additional pressure or temperature transmitters. The temperature difference between these sensors generates a voltage output, which is proportional to the media cooling effect. One RTD is heated while the other senses the actual process temperature. Two thermowell-protected platinum resistance temperature detector (RTD) sensors are placed Flowmeters with thermal-dispersion sensors provide direct mass-flow measurement. These meters have good accuracy and wide turndown, but are Light beam, and the time it takes for these particles to travel from one laser beam to the other laser beam can be used to calculate the gas velocity and volumetric flowrate. This technology requires the presence of particles in the gas stream. Flowmeters designed with optical sensing rely on laser technology and photo detectors. The shift in frequencies between the transmitter and receiver can be used to generate a signal The transmitted frequency of the beam is altered linearly by particles or bubbles in the fluid stream. In ultrasonic flowmeters, a transducer emits a beam of Flowmeters designed with ultrasonic flow-sensing technology rely on ultrasound and the Doppler effect to measure volumetric flowrate. That require frequent maintenance in order to maintain accuracy. If the gas is dirty, there can be orifice clogging issues ![]() To move through or past two points of reference, creating a differential pressure rate that is equivalent to the rate of flow using the Bernoulli equation with some modifications. The typical DP meter designs require the fluid Differential pressure (DP) meters and sensors come in several designs, including orifice plates, pitot tubes and Venturis. The principle of operation for Coriolis flowmeters relies on a vibrating tube where the flow of fluid causes changes in frequency, phase shift or amplitude, which is proportional to the mass flowrate.Ĭoriolis meters are highly accurate and are frequently used in custody transfer applications, but they are on the expensive side and require labor-intensive inline applications.ĭifferential pressure. Generally, the best choice is mass-flow sensing technology when measuring air or other gases - especially in critical applications.Ĭoriolis. Volumetric technologies can measure gas flowrates, there can be problems with totalized flow. Liquid is primarily measured in terms of volumetric flowrate, while gas is a mass-flow measurement because of the unique properties of gases when compared to liquids. There are two basic types of flowmeters: liquid and gas. Or environmental compliance issues occur, then the cost of failing to recognize the subtle differences in air and other gas flow-measurement technologies can be punitive. If safety events, poor product quality, a production slowdown The cost of choosing the wrong flowmeter - in terms of extra maintenance, repairs and spares in large CPI plants - can add up quickly to tens of thousands of dollars. The wrong choice in a different application - even one that is in close proximity within a facility. The same flow-sensing technology that is chosen for one application in a plant is quite possibly The truism “knowledge is power” definitely applies when it comes to choosing a flowmeter for gas measurement tasks in CPI plants. Its own strengths and weaknesses, depending on exactly what material needs to be measured, the required accuracy, where it needs to be measured and so on. There are six to eight viable flow measurement technologies for gases available today, but only about half of them are suitable for the heavy-duty metering applications found in the most challenging CPI operations. When the measurement of air or other gases is inaccurate or inconsistent, some potential outcomes include serious accidents, emergency shutdowns, unplanned maintenance, production slowdowns or cost overruns. The measurement of air and other gases in manufacturing plants in the chemical process industries (CPI) is essential in many functional applications, including safety, process control, product quality, production efficiency, environmentalĬompliance and costs. ![]()
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