Outdoor landscape lighting fixtures need to withstand the test of snow and ice sun, wind and rain thunder and lightning for a long time, and the cost is high, and because the use of the outer wall is more difficult to dismantle and repair, it must meet the requirements of long-term stable work. The LED is a delicate semiconductor component, if damp, there will be a chip moisture absorption phenomenon, damage LED, PCB and other components, therefore, LED is suitable for working in dry and low temperatures. To ensure the long-term stable work of LED in harsh outdoor conditions, the waterproof structure design of the lamp is extremely critical.
At present, the waterproof technology of landscape lighting fixtures is mainly divided into two directions: structural waterproof and material waterproof. The so-called structural waterproof is that after the combination of various structural components of the product, it has waterproof function. The material waterproof means that when the product is designed, the position of potting glue to seal the electrical components is set aside, and the glue material is used to achieve waterproof during assembly. The two waterproof designs are suitable for different product routes, and each has its own advantages.
Structural Waterproofing
Landscape lighting fixtures based on structural waterproof design, need to closely match silicone sealing ring waterproof, shell structure is more sophisticated and complex, usually suitable for large size lamps, such as strip floodlights, square and round floodlights and other medium and high-power lamps. Structural waterproof lamps only do pure mechanical structure assembly, simple to use tools, less assembly processes and processes, short assembly cycle, and convenient repair on the production line. The lamps pass the electrical performance and waterproof test, and can be packed and shipped, which is suitable for engineering projects with short supply cycle.
Following design points：
(1) Design silicone waterproof ring, choose the right hardness of the material, design the right pressure, its cross-section shape is also very critical. The cable inlet line is the channel of water seepage, waterproof wire should be selected, and the use of strong cable waterproof fixed head (PG head) can prevent water vapor from penetrating from the gap in the cable core, but the premise is that the wire insulation layer does not age and crack under the long-term strong extrusion of the PG head.
(2) At normal temperature, the linear expansion coefficient of glass is about 7.2×10 ~ m/(m·K), and the aluminum alloy is about 23.2× 101 m/(m·K), and the difference between the two is large. When the external size of the lamp is larger, it must be carefully considered. Assuming that the length of the lamp is 1 000 mm, the shell temperature is 60℃ during the day, the temperature drops to 10℃ in rain or at night, and the temperature drops by 50℃, the glass and aluminum profile will shrink 0.36 mm and 1.16 mm respectively, the relative displacement is O.8 mm, and the sealing element will be pulled repeatedly during the repetitive displacement process, affecting the air tightness.
(3) Many medium and high-power outdoor LED lamps can be installed waterproof ventilation valve (respirator) using the waterproof and breathable function of molecular sieve in the respirator, balance the internal and external air pressure of the lamp, eliminate negative pressure, prevent human water vapor absorption, and ensure the internal drying of the lamp. This cost-effective waterproof device can improve the waterproofing ability of the original structure design. However, the respirator is not suitable for buried lights, underwater lights and other lamps that often soak in water.
The long-term stability of the waterproof structure of the lamp is closely related to its design, the performance of the selected lamp materials, processing accuracy, and assembly technology. If the weak link deformation and water seepage, the LED and electronic devices will cause irreversible damage, and this situation is difficult to predict in the factory inspection process, with sudden. Therefore, to improve the reliability of structural waterproof lamps, it is necessary to continue to improve waterproof technology.
Material Waterproofing
The lamps with waterproof material design use filling potting glue to insulate and waterproof, and use sealing glue to seal the joints between structural parts, so that the electrical parts are completely airtight and achieve the waterproof role of outdoor lamps
