Overview
Vortex flowmeters are based on the Karman vortex street theory. The shedding frequency of Karman vortex streets is proportional to the flow velocity . Therefore, the instantaneous flow rate can be calculated by measuring the shedding frequency of the Karman vortex street.
The vortex shedding frequency of a vortex flowmeter sensor is alternately exerted on the detection sensor (probe) by vortices. The stress is detected by a piezoelectric crystal or a differential capacitor element inside the sensor, which is used to manufacture this type of velocity-based flowmeter.
Piezoelectric Vortex Flowmeter: The stress-type vortex flowmeter is a type of velocity flowmeter. Based on the Karman vortex street theory, it uses a piezoelectric crystal to detect the vortex frequency generated when the fluid passes through a three-column bluff body inside the pipeline, thereby measuring the flow rate. It features a simple and robust structure with no moving parts prone to wear, resulting in a long service life, high measurement accuracy, a wide range, and minimal pressure loss.
Capacitive Vortex Flowmeter: The probe of a capacitive vortex flowmeter sensor consists of a pair of differential capacitors. The alternating vortex forces generated by the vortex shedding act on both sides of the probe, causing changes in the differential capacitance inside the probe. These changes are converted by an amplifier into flow pulse signals. The unique internal structure provides the probe with good vibration resistance and the ability to measure minimal flow rates. The base of the probe's capacitor plates is made of imported ceramics formed at over a thousand degrees Celsius, offering excellent high-temperature resistance. The craftsmanship and structure of the core components ensure higher reliability. The intelligent sensor is gas-liquid universal, with automatic frequency tracking on the communication frequency band, eliminating the need for potentiometers or toggle switches to adjust the frequency band and sensitivity. There is no zero drift, and the range can be freely set, truly achieving on-site zero-point adjustment-free operation. The circuit suppresses different vibration frequencies, enhancing vibration resistance and linearization.
It is widely applied in various industries such as petroleum, chemicals, metallurgy, machinery, food, papermaking, as well as in urban pipeline heating, water supply, coal gas, and other sectors for the measurement and energy-saving management of various low-viscosity liquids, gases, steam, and other single-phase fluids.
Product Features
- Adopts a low-power CPU central processor and LCD display, resulting in low power consumption.
- Simple installation and highly convenient maintenance, with a long calibration cycle, typically two years.
- Wide measurement range: The normal range is 1:10, and the range ratio can reach 1:15.
- Low pressure loss and low operating costs, offering greater energy-saving benefits.
- Within a certain Reynolds number range, the output signal is unaffected by changes in the physical properties and composition of the measured medium. The meter factor is only related to the shape and size of the vortex generator, and generally, there is no need to recalibrate the meter factor after replacing components.
- It can display on-site, transmit over long distances, and connect to computer control systems.
- The detection probe does not directly contact the measured medium, resulting in more stable performance.
- The integrated design of temperature and pressure compensation and the photoelectric isolated current output provide excellent anti-common-mode interference suppression capability.