Structure and quality analysis of explosion-proof electrical products

Although China's explosion-proof electrical products have been developing for so many years, they have hardly changed much in terms of structure and quality. The backward performance of our products is an indisputable fact. In foreign countries, many products' advanced structures and processes have made us refreshed, and our products have not improved much in the past decades. The root cause is that our processes are backward, our process equipment is backward and our products are backward. Many companies are reluctant to invest more in technology, tooling and new product development, and are satisfied with the status quo. Some companies simply do not want to improve products, remodeling and perfection, and only pursue immediate interests. In addition, our products do not pay much attention to the design and processing of the products. The products produced are always rough and unsightly. In fact, it can be done better with a little effort. In addition, there are many unreasonable phenomena in the structure of China's explosion-proof electrical appliances.

For example, the flameproof surface between the lampshade of the flameproof lamp and the casing is generally fastened by a two-point folding structure. If a lamp has a diameter of 150 mm and a circumference of more than 450 mm, imagine whether the flameproof surface can meet the requirements after tightening. According to the investigation, such a structure gap is excessive. In addition, in order to pursue small size (saving materials), some manufacturers have made small space inside the shell, and can barely put components into it. Some have reached the point where it is extremely difficult to change a line. Such a small space is very detrimental to both electrical performance and product performance. In other manufacturers, there are many problems in the explosion-proof products, such as the explosion-proof surface, the explosion-proof gap, the surface roughness and the length of the explosion-proof surface, which are not critical to the conditions of the explosion-proof factor.

For example: the length of the screw hole to the edge of the flameproof joint surface, the design and processing of the blind hole, the flatness of the flameproof surface, and the treatment of the surface blisters. What's more, it should have been a blind hole, and it was processed into a through hole. There is also the observation window problem. The observation window of the explosion-proof electrical products is a weak link. The standard has made stricter regulations. Many manufacturers can glue the transparent parts. As for whether it meets the requirements, it is not known. There are still many similar problems like this. The main aspects are summarized as follows:

1. The bolts between the large cover of the explosion-proof product and the main cavity are spaced apart by more than 200 mm. It is difficult to ensure the explosion-proof gap and pass the explosion test.

2. Explosion-proof transformers usually use an ordinary transformer in an explosion-proof enclosure to become an explosion-proof transformer. After installing the transformer into the explosion-proof enclosure, as the heat dissipation conditions change, it does not take into account the problems of temperature rise, short circuit, insulation, etc., just add an explosion-proof enclosure.

3. For the plugging and unplugging device, there is a lack of insertion and insertion force, contact resistance requirements and arc extinguishing requirements.

4, many heat-explosive products only add an explosion-proof junction box with ordinary products, that is, become an explosion-proof product, such as: electric heaters, electric heaters and other products.

5, the fan products are also the same as above, except that the ordinary fan is equipped with an explosion-proof junction box, which is an explosion-proof type product. It should be noted that the main components and the motor should also be in the form of explosion-proof.

6. In the production and manufacturing process of the explosion-proof casing, the hydraulic pressure test shall be carried out one by one according to the standard requirements. Now many enterprises do not carry out the hydraulic test or only the sampling test. For the non-standard products, the hydraulic test is not carried out at all.

7. Because the factory uses a large number of cast aluminum alloy casings for explosion-proof electrical appliances, it is reasonable to use ZL102 material in the standard. Some products are mixed with a large amount of miscellaneous aluminum, and some even use explosion-proof casings made of miscellaneous aluminum. It is to get the profit as much as possible.

8. The gap between the explosion-proof terminal block and the housing is more serious than the gap.

9. For dust explosion-proof electrical appliances, due to the increasing demand for dust explosion-proof electrical appliances in recent years, some manufacturers have also changed production. However, most enterprises have changed the original explosion-proof products to a name, and they have not manufactured according to the relevant standards.

10. For the product nameplate, many manufacturers simply do not pay attention to this. First of all, some of the materials are made of aluminum, some are made of self-adhesive, and they are not made of copper at all. In addition, for the content on the nameplate, it is first necessary to comply with the standards and the main technical parameters should be marked so that the user can clearly understand the main performance indicators of the product.

11. In the product manual, the protection requirements of the product in the process of installation are often lacking. For example: installation height, rain, snow protection, etc., especially for outdoor products, if the confession is unclear, it is easy to cause product damage.