In the assembly of flameproof equipment, the following key considerations should be observed by operators:
1. Adhere strictly to the “Component Confirmation Principle.” This involves a thorough inspection of components for any damage or defects, followed by a detailed internal cleaning.
2. Diligently clean the flameproof joint surfaces and apply specialized anti-rust greases, such as the type 204-1. Traditional greases like butter should be avoided.
3. Each non-threaded screw length and non-threaded hole depth must be scrutinized to ensure they align with design specifications. It’s critical that the non-threaded areas leave a margin of double the thickness on the spring washer threads post-assembly.
4. Meticulously assess the actual effective coupling length and gap of the flameproof structure. For planar joint surfaces, apply a thin layer of grease (or an alternative medium) to one side. After pressing and moving it against the other joint surface, measure the impression’s width to determine the actual effective coupling length. The coupling gap should be verified with a feeler gauge to meet the standards. If measurements fall short of the design criteria, component recombination through swapping is permissible to achieve adjustment.
5. Special attention is required for gaps in cylindrical flameproof structures made from differing materials. Due to the variation in thermal expansion coefficients, the gap between components such as terminal insulation sleeves and conductive bolts can widen significantly with temperature increases. To mitigate this, components with the minimum post-fitting gap should be selected, or even an interference fit should be considered.
6. Prior to finalizing the component assembly, reapply arc-resistant paint on the inner surfaces of junction boxes and main cavity walls that house spark contact points.
