As a flame-proof explosion-proof light fixture, it must have a certain light-transmitting part. At present, China is basically made of glass material and fixedly installed on the cavity of the explosion-proof light fixture. Therefore, these glass transparent parts of flameproof lamps must not only meet the requirements of the impact test and thermal shock test for the transparent parts, but more importantly, they must withstand the dynamic strength test.
This requires that these transparent glass parts need to have sufficient strength, that is, they must have sufficient thickness and a certain geometric distribution, and undergo processing such as tempering.
When designing transparent glass parts, we must pay attention to the reasonable selection of glass thickness and the determination of shape. Everything is premised on avoiding uneven stress in the finished product of the transparent parts, and at the same time, it is necessary to ensure that there is no sudden change in thickness.
The main advantages of glass are that it can maintain its physical and light transmission properties under high temperature, ultraviolet radiation and long-term humid conditions, the surface is resistant to scratches by hard particles, and it is allowed to be immersed in aqueous or organic solvents without causing stress. Cracks or corrosion.
The main disadvantage of glass is its brittleness and low tensile strength.
In order to make up for these shortcomings, when designing the assembly structure of the glass transparent part and the lamp body, a gasket is usually inserted between the glass transparent part and the metal parts of the lamp housing to prevent point contact with the metal parts of the housing and damage the glass transparent part.
In order to prevent the impact of solid foreign objects from breaking the glass transparent parts, the commonly used method is to add a grille to protect it. If no grille grille is installed, the glass transparent parts must pass the high-energy impact test.
Generally, when the transparent parts of explosion-proof light fixtures and lanterns adopt a sealed structure, the thickness of the gasket must not be less than 2.0mm, and the width of the embedded part of the gasket between the metal shell and the glass transparent part must not be less than 10.0mm. At the same time, glass transparent parts should generally be installed in the inner cavity, because when there is pressure inside, the elastic gasket tends to be compressed, which will strengthen the sealing performance.
The material of the elastic gasket is generally made of nitrile rubber; when the power of the lamp is large, asbestos rubber sheet or silicone rubber, fluorine rubber and other materials that are self-extinguishing by fire can be used.
It must also be noted that when installing glass transparent parts, measures should be taken to ensure that the periphery of the lampshade, glass tube and transparent plate should be compressed structurally, and the force should be uniform to avoid dangerous mechanical stress inside the transparent parts.
For the glass transparent parts of explosion-proof explosion-proof light fixtures, it can also be sealed and fixed by direct glue sealing with the shell lamp body. This kind of structure has higher requirements on the sealing material, and silicone rubber is suitable. The fixing of the transparent part of the luminaire and the housing part must be ensured in structure that when the light source is replaced, the transparent part and the sealing part shall not fall off from the housing part.