Welcome back to this article! We are thrilled to introduce you to the incredible working principle of the Coriolis flow meter.
Invention of the Coriolis Flow Meter
The Coriolis flow meter derives its nomenclature from the French engineer and physicist Gustave Gaspard de Coriolis (1792-1843). However, the invention of the Coriolis flow meter is attributed to James E. Smith of the United States. It's commenced in the early 1950s. Nevertheless, the practical technical challenge of moving a fluid in a straight line while in a rotating system remained unresolved. It was not until the mid-1970s that James E. Smith ingeniously introduced the fluid into the measuring tube in a state of resonance, thereby inventing the resonant direct mass flow meter. This innovative device employed the Koch effect to merge the two motions.
Principle of Invention
G.G. Coriolis, a French engineer, discovered that because the Earth rotates, it often pushes objects on its surface to the side. In the northern hemisphere, the Earth pushes them to the right. In the southern hemisphere, the Earth pushes them to the left. This push has a big effect on the tides and the weather. We can understand the reason for this phenomenon by considering the rotation of the Earth. Since the slower-rotating, higher-altitude surface of the Earth will deflect an object moving toward either pole eastward, Coriolis defined this drift as the Coriolis force.
Coriolis Flow Meter Working Principle
The fundamental principle underlying the Coriolis flow meter is predicated on the Coriolis force. The ensuing detailed exposition elucidates the underlying mechanics.
Assume a mass of (m) is in motion at a velocity (v) within a reference system that is rotating with an angular velocity (w). A force perpendicular to both the velocity and the angular velocity acts on it. We formally designate this force as the Coriolis force, and express it as F = 2mw.
Siemens SITRANS FCS700 Coriolis Flow Sensor
The following processes are fundamental to the operation of a Coriolis flow meter:
Vibration system:
The Coriolis flow meter is composed of several key components, including the measuring tube, driving system, and detection system. The measuring tube is the primary component that generates the Coriolis force. It typically takes the form of a straight tube, curved tube, or other shapes. The driving system provides a specific frequency and amplitude of reciprocating vibration to the measuring tube, with the general vibration direction perpendicular to the direction of fluid flow.
The fluid flow generates the Coriolis force:
When the fluid flows through the vibrating measuring tube at a velocity (v), we can consider the reciprocating vibration of the tube equivalent to the fluid being in a rotating reference system, as the vibration can be equated to a special kind of rotary motion. According to the principle of the Coriolis force, the Coriolis force (F) acts on the fluid, and its magnitude is related to the mass flow rate of the fluid, the angular velocity of vibration of the measuring tube, and other factors. The Coriolis force will cause the measuring tube to twist or deform.
Detection and signal output:
The detection system consists of sensors and associated components. Expert design these components to identify any distortion or deformation of the measuring tube. These components are essential in detecting the effects of the Coriolis force. This distortion leads to phase changes in the vibration at various points on the measuring tube. The sensor then converts these phase changes into electrical signals. Through processing and analyzing these signals, the magnitude of the Coriolis force on the fluid can be calculated, enabling the determination of the fluid's mass flow rate. The Coriolis force is directly proportional to the mass flow rate, meaning that the mass flow rate of the fluid can be accurately measured based on the detected Coriolis force.
Pros and Cons of Coriolis Flow Meter
Pros:
High-precision Measurement:
The adoption of advanced sensor technology and signal processing algorithms ensures high measurement accuracy, making it suitable for accurately measuring the mass flow rate of various fluids. Additionally, users can control the measurement error within a small range under different working conditions. For instance, the measurement accuracy for most fluids can reach ±0.1% or higher.
Wide range of fluid adaptability:
It is capable of measuring a variety of complex fluids, including those with high viscosity, low conductivity, gas-liquid-solid multiphase flow, and more. It is suitable for use in various industries, such as petroleum, chemical, food and beverage, and others. The instrument operates reliably in different fluid measurement scenarios, and changes in the physical properties of the fluid do not significantly impact it.
Bidirectional measurement function:
This is capable of accurately measuring fluid flow in both forward and reverse directions. It is well-suited for two-way fluid flow processes, such as those found in certain circulatory systems or bidirectional transportation pipelines. It does not require the installation of complex reversing devices, making it a convenient option for flow measurement and system control.
Intelligent diagnosis and remote monitoring:
It has smart diagnostic functions that monitor the instrument's status in real time. It can detect sensor failure, pipe blockage, and other problems. This can provide feedback to the operator through on-site displays or remote communication. The product supports various communication protocols, making it easy to integrate into industrial automation control systems. It allows for remote monitoring and data management, improving the automation and management efficiency of production processes.
High reliability:
Product design and manufacturing follow strict quality standards. High-quality materials and advanced manufacturing processes are used. The measuring tube and other key components are resistant to wear, corrosion, and fatigue. They can operate stably for a long time in harsh industrial environments. This reduces maintenance costs and downtime.
Siemens SITRANS FC720/740 Coriolis Flow Meter
Cons:
High cost investment:
It comes with a relatively high purchase price. Installing and maintaining it demand high - level technical skills. This means that we may need specialized technicians to operate the equipment, which increases the cost of manpower. Also, in some large - scale applications, the overall cost will be higher.
Harsh installation conditions:
The installation location has very high requirements for the vibration environment and pipeline support. This means that installers need to ensure that there is no strong source of mechanical vibration around. It also means that they must make the pipeline support solid. Avoiding external factors that could interfere with the measurement accuracy necessitates this. If the installation site doesn't have enough space or the piping layout is complicated, installers may face more difficulties and higher costs during the installation process.
Limitations of large-diameter instruments:
For large-diameter pipeline applications, the volume and weight of the Siemens Coriolis flowmeter will increase a lot. This will make installation and maintenance more difficult. It will also make the instrument respond more slowly and affect its measurement accuracy.
SITRANS FC120/140 Coriolis Flow Meter
Our meters meet a variety of industrial needs. We will work with you to recommend the ideal Coriolis flow meter for your process. Contact ANTLET TEAM today to turn your flow measurement dreams into reality!