What are the differences in process technology between explosion-proof and conventional borescopes?

Conventional endoscopes strive for high performance, high definition, and durability, while explosion-proof endoscopes prioritize absolute safety and reliability above all else. This core difference is reflected in every process step, from design, materials, circuitry, to manufacturing. The following are the key differences in their processes:

1. Circuit Design and Component Processing

Conventional endoscopes:

Goal: Optimize performance. Strive for higher image resolution, brighter illumination, and faster transmission speeds.

Processing: Utilize standard mainstream electronic components and circuit design. High-power LEDs, high-performance CMOS sensors, and complex processing chips may be used. Circuit board (PCB) layout prioritizes signal integrity and performance.

Explosion-proof endoscopes (core intrinsically safe):

Goal: Energy limitation. Ensure that the energy of sparks or thermal effects generated by the circuits remains below the minimum ignition energy of flammable gases under any normal or fault conditions.

Processing:

Precise current/voltage limiting circuitry: Precision resistors, voltage regulator diodes, fuses, and other components must be used to form a multi-layered protection circuit to strictly limit voltage and current to safety thresholds. Rigorous Component Screening: All components must not only be of high quality, but also possess extremely stable and consistent parameters (such as capacitance, inductance, and power) to enable precise energy calculation and control.

Energy Storage Component Control: Extremely strict specifications are imposed on the capacitors and inductors in the circuit (especially the micro-LED driver circuit and sensor circuit at the probe tip). Their stored energy must be calculated to ensure that, even in a short circuit, the energy released is insufficient to ignite explosives in the environment.

Safe PCB Layout: Track spacing and creepage distances must comply with explosion-proof standards to prevent breakdown or leakage between high-voltage differential lines.

2. Structural Design and Sealing Process

Ordinary Endoscopes:

Goal: Dustproof, waterproof, and corrosion-resistant. Typically, a protection level appropriate for ordinary environments is used to ensure protection against damage from liquids and dust during daily use.

Processing: Common sealing methods such as O-rings and sealants are used.

Explosion-proof Endoscopes:

Goal: Prevent sparks and surface overheating. Process: Flameproof Enclosure (Complete Unit): The enclosure is typically constructed of insulating materials and features a robust sealing process.

Enhanced Sealing: While the probe may not necessarily be flameproof, its sealing requirements are far higher than those of standard endoscopes, ensuring that flammable gases cannot enter the internal circuitry.

Screwless Design or Special Screws: The enclosure is often secured with screws made of special, non-magnetic or corrosion-resistant materials, and they require a specific torque to ensure uniformity of the joint surface.

3. Material Selection and Process

Standard Endoscopes:

Goals: Lightweight, durable, and cost-effective.

Materials: Extensive use of engineering plastics, standard stainless steel, and lightweight aluminum alloys.

Explosion-Proof Endoscopes:

Goals: Anti-static, impact-resistant, corrosion-resistant, and temperature-controlled.

Materials:

Anti-static Materials: Special plastics or rubbers infused with conductive fillers are used in the enclosure, such as the handle, to ensure that static electricity is safely discharged and prevents accumulation. Explosion-proof Enclosure: The primary function of the enclosure is to protect the intrinsically safe circuitry within from physical damage, dust intrusion, moisture, and the ingress of non-intrinsically safe energy. Plastics with specific functionalities may be used.

Corrosion-Resistant Coating: Metal components often receive special coatings to prevent corrosion, which can alter critical dimensions of explosion-proof joints and impact safety.

Thermal Conductive Materials: Carefully designed heat dissipation paths, using thermal grease and heat sinks, ensure even heat dissipation from components, avoiding localized "hot spots" that could cause excessive surface temperatures.

4. Manufacturing and Quality Inspection Process

Ordinary Endoscopes:

Quality Inspection Focus: Image quality, functional integrity, and waterproofness.

Explosion-proof Endoscopes:

Quality Inspection Focus: 100% safety-related inspection.

Process:

Strict Tolerance Control: The dimensions of explosion-proof joints are inspected to ensure compliance with explosion-proof requirements.

Pressure Testing: Explosion-proof enclosures undergo sample pressure testing to verify that they can withstand the specified internal explosion pressure without damage or permanent deformation. Electrical parameter testing: Each device's circuit is tested to ensure that parameters such as voltage and current strictly comply with intrinsic safety certification documents.

Certification and traceability: Each explosion-proof endoscope must have a unique identification, and all key components and manufacturing processes are recorded and traceable. The entire product line must be certified by a nationally designated explosion-proof inspection agency.

Summary and Comparison

In short, the manufacturing process of explosion-proof endoscopes can be seen as adding an extremely stringent "safety barrier" to the precision manufacturing of conventional endoscopes. This barrier results in more complex designs, more expensive materials, and more stringent manufacturing and inspection processes. Ultimately, this ensures that the endoscope remains stable in hazardous environments and does not become a factor in causing explosions.