Analysis of the causes of water in sealed lamps

Main reasons for water leakage:

The high waterproof level usually needs to be completely sealed. Usually, this will cause the hot gas expansion problem when the lamp is working. Due to the temperature rise of the lamp and the external environment, the pressure difference between the inside and the outside of the lamp will decrease. After the lamp is used for a period of time, the temperature will decrease after the lamp is turned off, resulting in a negative Pressure, the seal is affected by the negative pressure caused by the water.

Through analysis: all outdoor high-power lamps have a breathing effect during work (except for explosion-proof lamps that are subject to high-pressure sealing). According to the thermodynamic principle, the volume expansion ratio is 1/273 for every 1 °C increase in air temperature.

For example, the net volume of an ordinary 210W high-power floodlight is 6.6 liters. In the environment of 20 °C, the temperature difference between the lamp cavity before and after turning on the lamp is about 80 °C, that is, 6.6×80/273=1.9 liter, indicating working time. The luminaire housing is to produce 1.28 atmospheres. The diameter of the water vapor molecules is 0.0004 microns, the diameter of the light mist with the smallest diameter in the rainwater is 20 microns, and the diameter of the drizzle is as high as 400 microns.

When the light is extinguished, the luminaire in the process is cooled by the rain, and the temperature in the lamp cavity drops sharply. The negative pressure generated forces the waterproof rubber strip or sealing glue to deform from the weak/thin under the action of air pressure. Inhalation, and poorly airtight lamps will directly inhale water vapor from various leaking places. This process is an inhalation process, which is affected by many factors such as the position of the suction port, the size of the gap, and the amount of rainfall, especially for lamps with better air tightness. Basically concentrated in this inhalation process. The probability of inhaling rainwater when the lamp is extinguished is 5-8%, and it increases with the increase of service life and the aging of waterproof rubber. If the pore diameter can be made between water vapor and rainwater The film can achieve both waterproof and breathable, balance the internal and external pressure of the lamp, eliminate the fog, balance the stress of the sealing strip, and effectively prevent the water and mist of the lamp.

It can pass 30-120L of air per square centimeter per hour, which can effectively solve the problem of waterproof and ventilation. It can effectively improve product reliability and reduce manufacturing and maintenance costs.