What is a pressure tight cylinder used to convey fluid or transmit fluid pressure called?

A pressure-tight cylinder designed specifically to convey fluid or transmit fluid pressure is known as a pipe. Pipes are typically constructed from materials that can withstand high pressure and are commonly used in various systems, including plumbing, gas lines, and industrial applications. Their rigidity and structural integrity are essential for safely transporting fluids under pressure.

In contrast, tubes are generally used for less demanding applications, often involving lower pressures. Hoses are flexible, making them suitable for transferring fluids in more dynamic settings but generally cannot withstand the same pressure as pipes. Cylinders, while they can be pressure-tight, are typically used in different contexts, such as in hydraulic systems, where they function as actuators rather than conduits for fluid.

Thus, the specific definition and characteristics of a pipe make it the most appropriate term for describing a structure that conveys fluid under pressure.