Ultrasonic flowmeter classification
Plug-in ultrasonic flowmeter: can be installed and maintained without interruption. Ceramic sensors are used for non-stop production installation using dedicated drilling equipment. Generally for mono measurement, in order to improve measurement accuracy, three channels can be selected.
Pipe-type ultrasonic flowmeter: the pipeline installation needs to be cut, but the subsequent maintenance can be stopped. Mono or 3-channel sensors are available.
External clip-on ultrasonic flowmeter: capable of performing fixed and mobile measurements. It is installed with a special coupling agent (silicone rubber cured at room temperature or high-temperature long-chain polymer grease) and does not damage the pipeline during installation.
Portable Ultrasonic Flowmeter: Portable, built-in rechargeable lithium battery, suitable for mobile measurement, with magnetic sensor.
1, non-contact measurement method, small size, easy to carry
2, suitable for on-site measurement of various sizes of pipe sound guiding media
3, built-in nickel-metal hydride rechargeable battery working time of more than 20 hours
4, user interface is flexible, easy to use
5, intelligent on-site printing function to ensure the integrity of the flow data
6, equipped with an integrated aluminum alloy protective box, can be used in harsh outdoor environments
Hand-held ultrasonic flowmeter: small size, light weight, built-in rechargeable lithium battery, hand-held, with magnetic sensor.
Explosion-proof ultrasonic flowmeter: used for explosive liquid flow measurement, it is explosion-proof and intrinsically safe. That is, the converter is explosion-proof and the sensor is intrinsically safe.
The flowmeter weighing impulse flowmeter that measures the flow using the impulse theorem is used to measure the flow rate of the granular solid medium, and is also used to measure the flow rate of the mud, the crystalline liquid, and the abrasive. Flow measurement ranges from a few kilograms per hour to nearly 10,000 tons. The typical instrument is a horizontal force-separated impulse flowmeter. The measurement principle is that when the measured medium falls freely from a certain height h to a detection plate with a tilt angle, an impulse is generated, and the horizontal force component of the impulse is proportional to the mass flow rate. Measuring this horizontal component can reflect the mass flow.
The electromagnetic flowmeter is made by applying the electric conductor to generate an induced electromotive force in a magnetic field, and the induced electromotive force is proportional to the flow rate, and is measured by measuring the electromotive force to reflect the flow of the pipeline. Its measurement accuracy and sensitivity are high. Industrially used to measure the flow of water, slurry and other media. The maximum diameter can be measured up to 2m, and the pressure loss is extremely small. However, media with low conductivity, such as gas and steam, cannot be used.
The electromagnetic flowmeter has a high cost, and the signal is susceptible to external magnetic field interference, which affects the wide application in industrial tube flow measurement. To this end, the product is constantly improving and updating, to the development of computer.
Several problems of steam metering and their solutions
Steam is one of the important energy sources for enterprise production. It is the main heat energy for urban central heating and an important indicator for economic accounting. Therefore, the accuracy of steam metering is particularly important.
In order to solve the problem of heating for employees, the company has updated the original boiler equipment, adding 4 new boilers (2 sets of 25t/h, and another 2 sets of 35t/h). The DCS realizes the automatic control of the boiler system, and the product is saturated steam.
Analysis of problems and influencing factors
Starting from the boiler ignition operation in November 2010, the steam flow often shows the maximum value, and the differential pressure signal measured by the differential pressure transmitter exceeds 20 mA. The same is true when the load is low and the actual flow is small. In this case, steam flow measurement does not provide a safety reference for boiler operation, and it cannot be used for cost accounting.
In response to this phenomenon, the design of the project uses a V-cone flowmeter, equipped with an intelligent differential pressure transmitter, and the measurement signal is sent to the DCS for calculation and display.