Pipes are long and hollow cylinders usually of circular cross-section, and typically used for fluid conveyance, but also for varying structural applications in the industry of engineering.
Although the terms ‘pipe’ and ‘tube’ are sometimes used interchangeably in everyday language, they are in fact regarded as distinct objects with unique traits in engineering lingo. Pipes are most often included in various assemblies, where they are connected through the use of fittings, whereas tubes can usually be built into custom shapes and sizes, or bent to specific configurations.
Pipes can thus have numerous uses, of which the most common are as part of domestic water systems, gas or liquid delivery, scaffolding, as components in different mechanical systems, casings, and so on. Depending on the what they are used for, pipes can be manufactured out of glass, fiberglass, rigid plastic, metal, ceramic or concrete. Glass pipes are often employed as smoking accessories, where filtration is also done through water held in a special container. As the smoke passes through the liquid environment, some of the heavier particles, as well as the water-soluble molecules, remain trapped in the water container.
Water smoking pipes are similar in construction to the hookah, a traditional Middle Eastern smoking pipe that uses water to cool off the smoke. While hookas are generally large and tall instruments, water pipes (or bongs) are usually smaller and portable. The functioning principle of the water pipe is the passing of air along a glass tube and into a bowl of water where bubbles are formed upon use.
Water pipes have been used traditionally in many parts of Asia and Africa for centuries, while they only became popular in the Western world sometime in the early 20th century. Historical records show that the water pipe was being used in China, for smoking tobacco and teas, in as early as the 16th century. Nowadays, the commercialization of water pipes is strictly regulated in many countries, although they can be used for smoking tobacco, teas and any other legal substances.
For engineering purposes, most pipes are manufactured out of steel, aluminum, copper, different types of plastic materials, as well as concrete or ceramics, mainly for low pressure applications such as drainage. For high temperature and pressure piping, high performance alloys of inconel, chrome moly, and titanium steel are used, while lead piping can still be found in some old water distribution systems, although the use of lead is no longer allowed due to its now known high toxicity.
Steel pipes can be joined and sealed by welding fittings or sealing joints with a special pipe thread compound; copper pipes can be joined by soldering, brazing, or compression fittings; whereas plastic pipes are usually joined together by solvent welding and heat fusion.
In complex assemblies, pipes are either supported from below or hung from above by specially designed pipe supports, that carry the weight of the pipe and materials within over a defined span. Therefore, the primary functions of pipe supports are to guide, stabilize, absorb shock and hold up a specific pipe structure.