Ultrasonic Flow Meter Model Selection
The ultrasonic flow meter is mainly composed of an ultrasonic transducer (or an ultrasonic flow sensor composed of a transducer and a measuring tube) and a converter installed on the measuring pipeline. The converter is divided into two categories: fixed-panel mounted and portable.
The transducer and the converter are connected by a dedicated signal transmission cable, and a junction box must be installed in an appropriate place for fixed measurement. The external clamp transducer usually needs to be equipped with an installation clamp and a coupling agent.
1. Selection of ultrasonic flow meter
1. According to the selection of the medium to be measured, first decide whether to choose the liquid type or the gas type.
2.2. Choose to use the mono channel type or the multi-channel type according to the measurement accuracy requirements. In general, the measurement accuracy of multi-channel ultrasonic flow meter is higher than that of single-channel ultrasonic flow meter.
3. According to the installation site conditions, choose to use external clamp ultrasonic flow meter or pipeline ultrasonic flow meter. If the pipeline at the installation site cannot be shut down or disconnected, the external clamp type can only be selected.
4. Choose ultrasonic flow meter according to economic ability and other factors.
2. Classification of ultrasonic flow meter
Ultrasonic flow meter can be classified from different angles.
1. Classification according to measurement principle: There are 5 types of closed pipes according to the measurement principle, and the two most commonly used are the propagation time method and the Doppler method.
2. Classification according to the measured medium: there are two types for gas and liquid. The propagation time method is dedicated to each of the two media. Due to the different operating frequencies of the transducer, the gas is usually between 100 and 300 kHz, and the liquid is between 1 and 5 MHz.
Gas instruments cannot use clip-on transducers because the ultrasonic transmission efficiency between the solid and gas boundaries is low.
3. Propagation time method is classified according to the number of channels: There are four types commonly used for the classification of the number of channels: mono, dual channel, four channel and eight channel.
In recent years, there have been three channels, five channels and six channels. Multi-channel configurations of four channels and above play a great role in improving measurement accuracy. Each channel can be divided into the following types according to the distribution position of the transducer.
a. There are two kinds of mono channels: Z method (transmission method) and V method (reflection method).
b. There are three types of dual channels: X method (2Z method, cross method), 2V method and parallel method.
c. There are two kinds of four channels: 4Z method and parallel method.
d. There are two types of eight-channel parallel method and two parallel four-channel cross method.
4. According to the transducer installation method, there are
a. Mobile installation b. Fixed installation