Pipe fittings are components used to join pipe sections together with other fluid control products like valves and pumps to create pipelines. The common connotation for the term fittings is associated with the ones used for metal and plastic pipes which carry fluids. There are also other forms of pipe fittings that can be used to connect pipes for handrails and other architectural elements, where providing a leak-proof connection is not a requirement. Pipe link fittings may be welded or threaded, mechanically joined, or chemically adhered, to name the most common mechanisms, depending on the material of the pipe.
There is some inconsistency in terminology surrounding the terms pipe, tube, and tubing. Therefore, the term pipe fittings will sometimes be mentioned in the context of tubing as well as pipe. While similar in shape to tube fittings, pipe fittings are seldom joined by methods such as soldering. Some methods overlap, such as the use of compression power fittings, but where these are commonplace for connecting tubes or tubing, their use in pipe connections is rarer. It suffices to say that while there are general distinctions, the common usage of terms can differ from supplier to supplier, although they represent the same items.
Pipe Fittings Explained: Fitting Materials and Manufacturing Processes
Cast and malleable iron
Fittings for cast iron pipe fall under hubless and bell-and-spigot styles. Hubless designs rely on elastomeric couplers that are secured to the outer diameters of the pipe or fitting by tension clamps, usually a stainless steel band clamp that compresses the elastomeric material and forms a seal. These hubless or no hub designs are sometimes referred to as rubber pipe couplings or rubber plumbing couplings and are especially popular for transitioning from one material to another—from copper to cast iron, for instance. Bell-and-spigot, or sometimes, hub-and-spigot, overhead line fittings are joined today primarily with elastomeric gaskets that fit inside the bell and accommodate the insertion of the plain pipe end or fitting. Older systems before the 1950s were caulked using a combination of molten lead and a fibrous material such as oakum. Cast iron pipe is sometimes joined with bolted flanges, or in some cases, mechanical compression connections. Flanged joints employed in underground applications can subject the pipe to settlement stresses unless the pipe is adequately supported.
The anti-vibration hammer is designed to reduce wind-induced wire vibration. High-voltage overhead lines have high pole positions and large spans. When the wire is subjected to wind, it vibrates. When the wire vibrates, the working conditions at the wire suspension are the most unfavorable. Due to multiple vibrations, the wire will be fatigue damage due to periodic bending. When the span of the overhead line is greater than 120 meters, vibration-resistant hammers are generally used to prevent vibration. The installation position of the anti-vibration hammer should be determined according to the construction requirements. After the anti-vibration hammer is installed, it can produce the movement opposite to the vibration of the wire, thus eliminating or weakening the vibration of the wire.
