How does tapered pipe thread seal

The torque increases if it is screwed into a cylindrical thread. In theory, this combination seals by compressing and wedging the two parts of the fitting. Due to manufacturing tolerances, the sealing effect is only achieved by means of a sealing tape PTFE tape or the application of a sealing agent.

Due to the less demanding manufacturing and quality requirements, tapered threads are cheaper than cylindrical threads.

In use, and especially in the case of repeated assembly, a weak point becomes apparent: the sealing agent needs to be re-applied for each assembly. Due to the fact that the thickness of the sealant can never be precisely determined, the installation depth of the union can vary.

Pre-assembled tubes may be too long or too short. For moulded components such as elbow unions or T-unions, the conical thread is an advantage, because the alignment of the component can be adjusted. NPS threaded connections need gaskets or O-rings to seal them. We've taken spring-loaded check valves to a whole new level. Mix and match imperial and metric connections. Watch the video. Conclusion Understanding tapered pipe threads makes it easier to choose the best component, especially tapered pipe fittings.

Parts with matching threads always perform better because matching threads are mechanically stronger and create better gas-tight and liquid-tight seals. What kinds of problems have you had moving between different tapered pipe thread standards when sourcing components for your application? Help us by telling others what you learned.

Have questions about tapered or straight pipe threads used on flow control components? In many cases switching to STO fittings may require some customization of the fittings or their respective components. These are costs and benefits for OEMs to weigh as part of their overall business plans.

Blog Home Contact Parker. June 16, by Fluid Gas Handling Team. Disadvantages of pipe threads The main disadvantage with pipe threads, however, is that voids in the connection still can remain. A far more reliable option A less common option for ports installed on air brake components, STO fittings may not be specified in systems with the frequency of pipe threads.

Watch this video and see how Parker is going the extra mile for the transportation industry: Article contributed by Samantha Smith, marketing services manager, Fluid System Connectors Division Related, helpful content for you: Why are Brass Fittings Preferred by Truck Manufacturers? Subscribe to All Feeds. Ball seats however refer to the spherical sealing surface inside a female thread swivel only that seals with the chamfer on the inside of a male thread.

These sealing systems all share a common trait in that there is a metal-to-metal seal created where the male and female surfaces contact not including the threads. Both Face Sealing and Boss Sealing fitting types utilize an encapsulated O-ring in order to create a seal.

The difference is that Face Seal fittings have the O-ring located in the grooved area at the end of the male thread, while Boss Seal fittings have the O-ring located at the base of the male thread. The corresponding female Face Seal fitting has a flat sealing surface that engages the O-ring in the male fitting and compresses it as the fittings are threaded together and creates a seal.

Look for a raised outer section on the male fitting where the bonded washer or seal would go; if it exists this indicates the fitting is Cutting Face.