How to install E+H electromagnetic flowmeter sensors?

(1) Installation location

Usually the protection level of the electromagnetic flowmeter sensor shell is IP65 (dustproof specified in GB 4208 Water spray protection level), the installation site has the following requirements.

1) When measuring mixed phase fluids, choose a place that will not cause phase separation; when measuring two-component liquids, avoid installing them downstream where the mixing is not uniform; when measuring chemical reaction pipes, install them in the reaction Fully complete the downstream of the section;

2) Try to avoid negative pressure in the measuring tube;

3) Choose a place with small vibration, especially for integrated instruments;

4) Avoid large motors, large transformers, etc. nearby to avoid causing electromagnetic field interference;

5) Places where it is easy to ground the sensor alone;

6) Avoid as much as possible There are high concentrations of corrosive gases in the surrounding environment;

7) The ambient temperature is in the range of -25/-10 ~ 50/60℃. The temperature of the integrated structure is also limited by the electronic components, so the range is narrower;

8) The relative humidity of the environment is within the range of 10% to 90%;

9) Avoid direct sunlight as much as possible;

10) Avoid rain Soakable and will not be submerged in water.

If the protection level is IP67 (dust-proof and water-proof) or IP68 (dust-proof and submersible), the above two requirements 8) and l0) are not required.

(2) Straight pipe section length requirements

In order to obtain normal measurement accuracy, there must also be a certain length of straight pipe section upstream of the electromagnetic flowmeter sensor, but its length is the same as that of most other flow meters. Less than required. After 90° elbows, T-shaped pipes, concentric reducers, and fully open gate valves, it is generally considered that as long as the straight pipe section is 5 times the diameter (5D) away from the electrode center line (not the sensor inlet connection surface), valves with different openings are 10D is required; the downstream straight pipe section is (2~3)D or no requirement; but the butterfly valve plate must be prevented from extending into the sensor measuring pipe.

The lengths of upstream and downstream straight pipe sections proposed by various standards or verification regulations are also inconsistent, as shown in the table below, and the requirements are higher than usual. This is due to ensuring that the current 0.5-level accuracy instrument requirements are met. ISO 6817 is the standard for the use of electromagnetic flowmeters. This standard believes that there should be at least 10D straight pipe for any type of flow disturbance, so that the performance change can be guaranteed not to exceed 1%. ISO 9104 and JJG 198 are documents proposed for evaluating the performance of electromagnetic flowmeters; the straight pipe length of JJG 198 listed in the table is for instruments with an accuracy of 0.5 and above.