Flowmeter selection key parameters

The key points of flow meter selection are as follows: According to the nature and flow conditions of the fluid to be measured, the flow sampling device and the type and specification of the measuring instrument, the type selection must fully comply with the conditions of the instrument provided by the process, consider the accuracy level, and economy. Sex, consider the safety of measurement.

1. Determine the type and specification of the flow meter according to the nature of the fluid to be measured and the flow conditions

The flow meter measures the nature of the fluid and the flow conditions determine the form and specifications of the flow meter. The first selection must consider several key physical and chemical properties of the fluid: the state of the fluid (gas or liquid), the conductivity of the fluid, the chemical corrosion of the fluid, and the viscosity of the fluid. Second, we must fully understand the scope of application of various forms of flow meters.

For example, an electromagnetic flow meter cannot measure gas but can only measure conductive liquid. If the fluid is corrosive, choose an anti-corrosion type flowmeter when selecting the type, especially the choice of wetted material, for example, when the electromagnetic flowmeter is used to measure the hydrochloric acid liquid, the electrode must be used or the electrode is easy to use. It was eroded.

2 The selection must fully comply with the instrument conditions provided by the process

The choice of flow meter should fully consider the instrument conditions provided by the process. For example, working pressure, working temperature, and flow rate, so we need to consider the pressure and temperature resistance of the flow meter and the choice of flow range. The maximum pressure resistance of the flowmeter should be slightly larger than the working pressure of the measured medium, generally 1.25 times, to ensure that no leakage or accident occurs. The choice of flow range is to measure the accuracy of the flow meter, choose a small, easy to overload, damage the instrument; large selection, which hinders the accuracy of the measurement.

3 Consider accuracy levels and economics

Different flow meters will have different measurement accuracy, different manufacturing conditions, different processes, and different accuracy. In the general production equipment, only the general reference of the flow rate is usually the lower price of the glass rotor and metal rotor and other inexpensive flowmeters, the production of public works on the gas (air, nitrogen, steam) usually use vortex flowmeter All kinds of water are mainly used electromagnetic flowmeters, flowmeter selection must be economic and can meet the accuracy requirements.

4 Consider the security of measurement

However, what is the product, safety is to be considered, and the flow meter is also the same, must be safe and reliable. The first measurement method is reliable, that is, the sampling equipment will not cause accidents due to mechanical strength or electrical circuit failure during operation. Second, the measurement instrument will not affect the safety of the production system under normal production or failure conditions. In the case of oil-fired power plants and flammable gases, explosion-proof instruments should be used.

Each kind of flow meter has its own characteristics, there are advantages and disadvantages, no flow meter can be universal in any occasion, any conditions, therefore, should be based on a comprehensive comparison of various measurement methods and instrument characteristics On the choice of suitable production requirements, both reliable and economical and durable type.

The choice of flow meter manufacturers must be professional, the correct analysis and selection can only purchase the most suitable flow meter.