The hub in pipe fittings is a cylindrical extension on a pipe fitting that is used to connect pipes together. Hubs are typically found on fittings such as elbows, tees, couplings, and flanges. The hub provides a way to connect the fitting to the pipe, making it an essential component in plumbing systems.
Hubs come in different sizes and styles, depending on the type of fitting and the size of the pipe it is meant to connect. For example, a hub on an elbow fitting may be tapered or straight, while a hub on a flange fitting may be raised or flat.
One of the most common types of hubs used in plumbing systems is the NPT (National Pipe Thread) hub, which is a standardized thread type used for connecting fittings to pipes. NPT threads are tapered and are designed to provide a tight, leak-proof seal when threaded together.
Another common type of hub is the solvent-weld hub, which is used to join PVC (polyvinyl chloride) pipes and fittings. Solvent-weld hubs are designed to be used with a special solvent-based cement that is applied to the outside of the pipe and the inside of the hub. The two parts are then pushed together, and the solvent evaporates, leaving a strong bond between the pipe and the fitting.
When installing fittings with hubs, it is important to follow the manufacturer’s instructions and to use the correct tools and materials. This will help to ensure that the connection is secure and leak-free.
In some cases, fittings with hubs may need to be adjusted or re-tightened after installation, especially if the plumbing system experiences changes in pressure or temperature. Regular inspection and maintenance of fittings with hubs can help to ensure that the plumbing system remains in good working order.
In conclusion, the hub in pipe fittings is a critical component in plumbing systems that provides a way to connect pipes and fittings together. Hubs come in different sizes and styles, and it is important to choose the right type of hub for the fitting and pipe being used. Proper installation and maintenance of fittings with hubs is also important for ensuring that the plumbing system functions correctly and does not develop leaks.