Lightning protection grounding is divided into two concepts. One is lightning protection to prevent damage caused by lightning strikes. The second is electrostatic grounding to prevent electrostatic hazards.
First, lightning protection is divided into the overall structure of lightning protection, the main ground hit the grounding, grounding, forming a grounding network, grounding resistance is less than 10 ohms. Then connect with the main body of rebar or steel. The concrete-cement roof is connected with lightning protection strips or lightning rods. There must be a grounding test point on the ground outside the wall, and the galvanized flat iron should be used for direct access to the roof.
Second, the grounding of the power supply system is divided into the protection grounding and the work point grounding. The protection grounding is the grounding of the live equipment housing. The grounding of the work point refers to the neutral ground. The grounding grid is the same as the lightning protection grounding method, and the grounding resistance is less than 4 ohms. If the requirements are not met, a grounding electrode should be added. If the conditions are not good, the electrolyte should be added and/or the soil replaced.
Third, instrumentation grounding system. The grounding resistance of this system is less than 1 ohm and it cannot be connected to lightning protection grounding.
Fourth, anti-static grounding, resistance is less than 30 euro.
The main test content of lightning protection grounding system is as follows:
1. Installation and inspection: Check the installation process of the equipotential bonding grid in the engine room, the installation process of the equipotential bonding wire of the equipment, the connection mode of the grounding terminal, and whether the color specification of the wire meets the national standard;
2. Functional verification: Test the grounding resistance of the equipment room and the resistance value of the equipotential connection in the engine room.
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Site Selection for Mass Flow Meter Installation
a) Sensor stays away from mechanical vibration source, for example, pump. Use flexible pipe to connect meter with pipeline if inevitable. The housing of meter must be standalone, out of touch with any other device. There must be 3 times the size of sensor between 2 sensors if there are many flow meters on the same pipeline, to avoid resonance.
b) Do not install sensor on pipeline that easily expands with hot and contracts with cold, especially near expansion joint, which leads to a worse stability.
c) Sensor stays away from industrial electromagnetic field, such as large generator and transformer, better 5m at least. Such device influences the performance of drive coil and pickoffs. Make sure magnetic field intensity less than 400A/m.
d) Sensor shall be installed on lower pipeline, to be easily full of fluid.
e) Make sure Ex-mark meet application requirements if in hazardous area.
f) Build a sunshade if the meter is under direct solar radiation. g) Keep the meter from corrosive liquid.
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Zhejiang Sealand Technology Co., Ltd. , https://www.sealandflowmeter.com