BSP threads with captive seals are widely used in industrial applications. Their sealing performance directly depends on the correct installation of the sealing ring, and the installation depth of the sealing ring is one of the key factors ensuring a good seal. BSP threads are divided into parallel threads (BSPP) and tapered threads (BSPT). BSPP threads cannot form a seal on their own and must rely on a sealing ring or sealant to achieve the sealing function of the connection. The installation depth of the sealing ring directly affects its compression and sealing contact area, thus determining the reliability and durability of the seal.
In BSP thread-with captive seal connections, the sealing ring is typically placed in a specially designed groove. The depth of the groove must be precisely determined based on the cross-sectional diameter of the sealing ring and the expected compression. If the installation depth is insufficient, the sealing ring cannot be fully compressed, resulting in insufficient contact pressure at the sealing surface and thus leakage. Conversely, if the installation depth is too large, the sealing ring may be permanently deformed due to over-compression, or even squeezed out of the groove, which will also compromise the sealing effect. Therefore, the installation depth of the sealing ring must strictly adhere to design specifications to ensure that it can form an effective seal under operating conditions and maintain long-term stability.
The installation depth of the sealing ring is also closely related to the width and shape of the groove. The groove width is typically designed as a specific multiple of the sealing ring's cross-sectional diameter to ensure that the sealing ring is not damaged by excessive stretching or twisting during installation. Simultaneously, the bottom and sidewalls of the groove must be smooth, avoiding burrs or sharp edges, as these defects can scratch the sealing ring surface and lead to seal failure. During installation, attention must also be paid to the method of introducing the sealing ring; the groove entrance is usually chamfered or rounded to reduce the risk of friction and damage during installation.
For BSP thread with captive seal connections, the choice of sealing ring material also affects the determination of the installation depth. Different materials for sealing rings have different compression set characteristics and elastic recovery capabilities. For example, rubber sealing rings may age under high temperatures or chemical media environments, causing changes in their compression and thus affecting the sealing effect. Therefore, when designing the groove depth, the characteristics of the sealing ring material must be fully considered, and sufficient adjustment space must be reserved to cope with the impact of changes in the working environment.
In practical applications, the installation depth of the sealing ring also needs to be adjusted according to specific working pressure and temperature conditions. Under high-pressure conditions, the sealing ring needs to withstand greater contact pressure. In this case, the groove depth needs to be appropriately reduced to increase the compression of the sealing ring, thereby improving sealing reliability. Conversely, in high-temperature environments, the sealing ring may soften due to thermal expansion. In this case, the groove depth needs to be appropriately increased to prevent the sealing ring from failing due to excessive compression. Furthermore, for connections that require frequent disassembly and reinstallation, the installation depth of the sealing ring must also consider its reusability to avoid performance degradation due to repeated compression.
The installation depth of the sealing ring in a BSP thread with a captive seal connection is a parameter that comprehensively considers multiple factors. It depends not only on the size and material properties of the sealing ring itself but also on the groove design, working pressure, temperature conditions, and installation process. In practice, installation must be strictly carried out according to design specifications, and the condition of the sealing ring must be checked regularly to promptly identify and address potential problems, ensuring the long-term sealing performance of the connection.
