Explosion-proof solenoid coils are special solenoid coils that are mainly used in environments where there is a risk of explosion. Its basic principle is based on the phenomenon of electromagnetic induction. When electric current passes through the coil, a magnetic field is generated around the coil. This magnetic field can interact with the iron core (if any) to generate solenoid force, which is used to drive various mechanical devices, such as opening and closing valves, starting motors, etc.
I. Explosion–proof principle and structural feature
1. Explosion-proof principle
Explosion-proof solenoid coils mainly use two common explosion-proof methods to ensure safe use in hazardous environments. One is a flameproof type, where the enclosure is able to withstand the pressure generated by an internal explosion and prevent the flame from propagating to the external environment. The other is the intrinsically safe type, which limits the energy in the circuit (including voltage, current, etc.) so that the sparks or thermal effects generated in normal operation and fault conditions are not enough to ignite the explosive mixture.
2. Structural feature
• Shell: High-strength metal materials are mostly used, such as cast aluminum, stainless steel, etc. The explosion-proof enclosure has strict wall thickness standards, and each connection point is equipped with high-quality sealing gaskets to ensure that internal explosion impact and flames will not leak out; the surface of the enclosure is also treated with plastic spraying, anti-corrosion coating, etc. to withstand erosion from harsh environments.
• Coil Winding: The winding wire is made of high insulating materials, such as polyimide enameled wire, and the winding is tight and even to ensure stable solenoid performance. Some products are designed with additional heat dissipation structures, such as additional heat sinks in the housing and internal heat conduction channels to prevent overheating of the coil.
• Terminal Blocks: Used for external circuits, sealed in a flameproof chamber or tightly sealed with sealant, which not only prevents the intrusion of external explosive gases, but also prevents internal electric sparks from leaking, ensuring reliable and safe electrical connections.
II. Application areas of explosion-proof solenoid coils
- Oil and Gas Industry: Mining link, drive the BOP solenoid valve, emergency shut down the wellhead. When conveying, the pipeline valves are precisely controlled to quickly cut off air and liquid flow in case of emergency. During the storage stage, control the breathing valve and safety valve to maintain normal air pressure in the tank and prevent oil and gas leakage and explosion throughout the process.
- Chemical Industry: In the reactor, control the feed and discharge valves and the stirring motor to ensure the accuracy and safety of the chemical reaction. In the material conveying pipeline, control the valve to stabilize the material flow direction and flow. In hazardous chemicals storage areas, operate ventilation, temperature control and isolation facilities to reduce the concentration of flammable gases and isolate dangerous areas.
- Coal mining industry: The underground ventilation system starts and stops the ventilator, opens and closes the damper, and disperses the gas. Drainage system, driving the drainage pump motor, regulating the valve, discharging water. In coal mining equipment, control motor starting, braking and hydraulic solenoid valves to facilitate efficient and safe mining.
- Pharmaceutical Industry: In the production process of raw materials, we manage and control the valves and motors related to reactors, centrifuges and dryers to strictly control the quality of drugs. Pharmaceutical packaging workshop, control filling machine, sealing machine automation components to prevent explosion and improve efficiency.
- Paints, coatings and inks industry: During the entire production process, it controls the stirring, heating, inlet and outlet valves of the reactor. During the entire production process, it controls the stirring, heating, inlet and outlet valves of the reactor.
- Application in dusty environment: Grain processing places, control of conveying, screening and dust removal equipment. Metal powder processing links, ensure the smooth operation of equipment in high dusty environment and curb dust explosions.
III. Key points for selecting explosion-proof solenoid coils
When selecting explosion-proof solenoid coils, the four principles of safety, reliability, applicability and economy should be followed in turn, and the selection should be made based on the following points:
• Pipeline parameters: Select a suitable solenoid valve according to the diameter specification (DN) and interface method.
• Fluid parameters: Select a suitable solenoid valve based on the material, temperature and other parameters of the medium.
• Pressure parameters: Select the appropriate solenoid valve principle and type according to the working pressure and structural requirements.
• Electrical parameters: Common voltage specifications such as AC220V and DC24V are preferred for easy use and maintenance.
• Working time: Select a normally closed, normally open or continuously energized solenoid valve based on the duration of continuous working.
• Environmental requirements: Select solenoid valves with auxiliary functions such as explosion-proof, check, manual, waterproof and fog-proof, water spray, and diving according to the installation environment.
Explosion-proof solenoid coils are an important safety device that plays a key role in several fields. When selecting and using it, its principles, structural characteristics and application areas should be fully considered to ensure that it can play the best safety protection role.
