The sealing design of compression fitting tees is a key component in preventing media leakage. Its effectiveness depends directly on the synergistic effect of material selection, structural optimization, and process control. In practical applications, media leakage often stems from inaccurate sealing surface fit, poor material resistance, or flawed installation techniques. Compression fitting tees utilize multiple technical approaches to systematically prevent leakage.
In terms of sealing surface design, compression fitting tees generally employ a composite structure combining metal hard seals and elastic soft seals. The metal hard seal achieves contact through precisely machined conical or spherical surfaces. For example, the tee incorporates molded elastic end seals embedded within the axial and radial sealing grooves. When the clamp bolts are pre-tightened, direct metal-to-metal contact forms a high-strength sealing zone, effectively preventing the penetration of high-pressure media. Simultaneously, an elastic soft seal layer, such as an EPDM rubber ring or fluororubber ring, is integrated into the socket, leveraging its compression-rebound properties to compensate for microscopic imperfections in the metal sealing surface, creating a dual protective barrier. This combined hard-soft design ensures seal reliability and extends service life.
Material resistance is another key factor in preventing leakage. Compression fitting tee connectors require matching sealing materials based on the media characteristics. For example, for chloride-containing or acidic media, corrosion-resistant Hastelloy or duplex stainless steel are used for the sealing surface. For hydraulic oil or grease, nitrile rubber or fluororubber seals are used. Furthermore, some high-end products feature ceramic coatings or polytetrafluoroethylene (PTFE) coatings on the metal surface to further reduce the risk of media corrosion. The compatibility of the material with the media directly determines the long-term stability of the sealing structure.
The installation process also plays a crucial role in sealing performance. Compression fitting tee connectors require strict torque control to ensure uniform compression of the sealing surfaces. For example, when installing a high-pressure tee, operators first lubricate the screws and tee of the pre-assembled terminal block, then insert the galvanized pipe into the terminal block, hand-tighten the nut, and then use a torque wrench to tighten the nuts in stages to the specified value. This step-by-step pre-tightening method prevents deformation of the sealing surface due to localized stress concentration and ensures the simultaneous effectiveness of the metal hard seal and the elastic soft seal. Deburring and chamfering the pipe ends before installation are also crucial steps to prevent scratches on the sealing ring.
Dynamic sealing technology is an effective means of addressing fluctuations in media pressure. Some compression fitting tee connectors incorporate a pressure compensation mechanism. For example, a spring-loaded ring is placed within the sealing groove. When media pressure increases, the spring is compressed, causing the sealing ring to expand radially, automatically filling the gap between the sealing surfaces. When pressure decreases, the spring returns to its original shape, maintaining the sealing pressure. This adaptive sealing mechanism effectively addresses cyclical fluctuations in media pressure and prevents leakage caused by pressure shock.
Furthermore, the sealing structure of compression fitting tee connectors incorporates anti-loosening features. For example, locking teeth or locking washers are added between the nut and the connector to prevent bolt loosening due to vibration or temperature fluctuations. Some products even utilize self-locking thread structures, leveraging friction generated by thread deformation to achieve permanent locking, fundamentally eliminating the risk of leakage caused by loose connections.
From a testing and maintenance perspective, the sealing structure of compression fitting tee connectors often includes a test port to verify the seal by injecting pressurized media or gas. For example, after the installation of a submarine pipeline repair tee connector, a pressure test is performed through the test port to verify that the sealing performance meets the requirements. This detectability design facilitates subsequent maintenance and allows potential leaks to be discovered and addressed in a timely manner.
