1. Basic composition and principle of drainage system
The drainage system of broken bridge casement window is mainly composed of drainage holes, drainage channels and water-retaining strips. The principle is to use the slope of the window sill to guide rainwater through the drainage holes into the drainage channels and finally drain to the outside. The drainage holes are usually set at the bottom of the window frame or near the bottom. The size and number of drainage holes should be reasonably designed according to the area of the window and the local rainfall. For example, in rainy areas, the number and diameter of drainage holes should be appropriately increased to ensure that rainwater can be discharged quickly. The drainage channel is the path connecting the drainage hole and the outside. The inner surface of the channel is required to be smooth, unobstructed, and have a certain slope so that rainwater can flow smoothly. The water-retaining strip plays a role in preventing rainwater from penetrating from the gap between the window frame and the window sash. Its material must have good weather resistance and elasticity, and can fit the window frame and the window sash tightly.
2. Common drainage system design problems
In actual design, there are some problems that affect the performance of the drainage system. First, the position of the drainage hole is unreasonable. If it is too close to the opening of the window sash, when the window sash is opened, rainwater is easily blown into the drainage hole by the wind, resulting in poor drainage or even backflow. Second, the design defects of the drainage channel, such as the channel is too narrow, too many bends or insufficient slope, will cause rainwater to accumulate in the channel, increasing the risk of leakage. Third, the water-retaining strip is improperly installed or of poor quality, which cannot effectively block rainwater, allowing rainwater to penetrate from the gap. For example, some low-quality water-retaining strips will harden and deform after long-term use, and lose their sealing and waterproof capabilities.
3. Optimization design strategy
In order to improve the reliability of waterproof leakage of the drainage system, a variety of optimization design strategies can be adopted. First, optimize the position of the drainage hole, set it away from the opening of the window sash and at the lowest point of the window frame. At the same time, a windproof cover can be added to the drainage hole to prevent rainwater from backflowing. Secondly, improve the design of the drainage channel, increase the cross-sectional area of the channel, reduce the bends, and ensure that the channel slope is not less than 5%. A U-shaped or sloped drainage channel design can be used to improve drainage efficiency. Furthermore, choose high-quality water-retaining strips, such as EPDM rubber strips, and use the correct installation method, such as applying special glue in the strip slot to ensure that the strip is tightly fixed, regularly check the strip status, and replace aging or damaged strips in time.
4. Waterproof leakage reliability test and verification
The drainage system after design optimization needs to undergo strict waterproof leakage reliability testing. A simulated rainfall test can be used to set the rainfall intensity according to 1.5-2 times the local maximum rainfall, and the continuous rainfall time is not less than 30 minutes to observe whether the window has leakage. At the same time, a wind pressure test can also be carried out to simulate the working conditions of the window drainage system under different levels of wind force, and check whether rainwater will flow back from the gap or drainage hole under the action of wind pressure. Through these tests and verifications, it is ensured that the drainage system of the broken bridge casement window can work reliably under various severe weather conditions, providing users with a dry and comfortable indoor environment.
