Differential pressure flow meter is an instrument that measures the flow rate according to the differential pressure generated by the flow detector installed in the pipe, the known fluid conditions and the geometric dimensions of measuring detector and the pipe.
Differential pressure flow meter has a long history of application, a high degree of standardization and a wide application. And its advantages are high degree of generalization, high accurate grade of theory, wide range of application, strong adaptability and low cost of the initial investment.
After a long period of practical application，We find the differential pressure flow meter also has some defects.
1. Many factors in practical application have great influence on the measurement accuracy, which makes the measurement errors increase and the accuracy decrease.
2. The installation project is very large, and the requirements are high, and it needs maintain frequently and has a lot of dismantling and washing project.
3.The use of differential transmitter is required. So its maintenance of workload increase largely.It needs to lay the pressure pipe, and the pressure pipe should be kept warm in winter, and can not be installed outdoors.
4. The ratio of measuring range is low, and it's very difficult to measure the small flow.
5. The pressure loss is large and the operation cost is high.