There are generally two kinds of bottle cap and bottle combination sealing methods. One is a pressure-sealing type in which the elastic material is cushioned between the two, and the elasticity of the elastic material and the extra driving force of the tightening force can achieve a relatively perfect seamless gap. Sealed, sealing rate of 99.99%. The structural principle is to pad a kind of ring-shaped special elastomer material at the butt joint between the bottle port and the bottom of the bottle cap. Currently widely used in the packaging of internal pressure, but also almost only the internal pressure need this form, such as Coca-Cola, Sprite and other carbonated soft drinks. As shown in the figure below (does not represent all patterns), the gray is the elastic pad.
Another form of seal is a plug seal. What is a plug? It should be easy for friends to think of the situation where we used a conical wood stopper soy sauce glass. Yes, the plug is sealed with its method of plugging it. The designer is based on this principle to design the bottle cap as a stopper. In the inner bottom of the bottle cap, one more ring is added. The first third of the ring is convex and fat, forming an interference fit with the inner wall of the bottle mouth. The effect of the plug. Sealed caps allow excluding screwing forces, sealing rate 99.5%. Compared with the previous method, the bottle cap is simple and practical, and the penetration rate is quite high. As shown in the following illustration, the figure on the right is a cross-sectional view that is easier to see.
Both methods have their own advantages and disadvantages. The pressure-sealing type requires an additional cost for the elastic gasket; the plug-type sealing method has less defects, but it is still a pragmatism, with some structural improvements. Already much higher