Desiccant application case on car headlights

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Desiccant application case on car headlights

Desiccant application case on car headlights

Problem Description:


1.The customer is a car sales and after-sales service in Shenzhen. Many of their customers report that the fogging of the car headlights in the rainy days is easy to fog, which has an impact on driving safety. They hope to seek help to solve the problem;
2.Although they have used some methods before, such as blowing with a hair dryer, or driving a high beam, but running for 4 hours, they still can’t dry the water inside the headlights;
3.Later they found us and learned that some car headlights are coated with an anti-fog coating. The anti-fog coating forms a flat water film by reducing the surface tension so that the light does not scatter, but this does not completely solve the internal There is a problem of water mist and fog, and some buyers are worried about the presence of water droplets inside the car. The situation of customer complaints is still increasing.

problem analysis:

1.First of all, it is necessary to distinguish whether the headlights enter the water or fog. The two are different from each other and need to be treated separately;
2.The complex external environment, as well as the pursuit of individual appearance, differentiated headlights, so that after the inside of the lamp enters the outside air (humidity), there is a temperature difference between the inside of the lamp housing (lower temperature) and the inside of the lamp (higher temperature). The presence of high and low temperature regions is one of the conditions for the presence of fog vapor;
3.The internal air of the lamp reaches a certain level (relative humidity), which is the second condition for the existence of fog steam;
4.When the above two conditions are met, when the hot and humid air inside the lamp comes into contact with the inside of the cooler lamp housing, the moisture will quickly condense into fog on the inside of the lamp housing;
5.Ordinary desiccant (silica gel, minerals, etc.) has a low moisture absorption rate of only 20%-30%. Considering space factor, it is recommended to use high-efficiency calcium chloride desiccant, which is smaller than silica gel and mineral desiccant. , but the moisture absorption rate is ten times higher (up to 300%), it is more space-saving, more suitable for being placed inside the lamp, and the absorbed moisture is stored as a gel, no longer dehumidified, and the moisture absorption time is up to 2 Months are even longer.

The experiment passed:

1.Place it for one month under normal room temperature environment (about 23 ° C, 50% RH)<
2.Place in a constant temperature and humidity chamber tester, and place the simulation environment for about one month (about 40 ° C, 90% RH).
3.In both environments, 100g of calcium chloride absorbs water vapor by 192g (about one time) and 305g (about twice).

Experimental results:

According to the experiment, the calcium chloride desiccant inside the lamp can absorb the water of 1 time of its own weight in the ordinary environment, and can absorb twice the weight of the water, which can absorb the inside of the lamp. Water fog fog conditions.

Use and precautions:

Change frequently, weather and environmental impact, change once or twice a month.
Use the method, put it in the car headlights as shown above.