Pipe spools are the components which can be welded or fitted to each other and constitute a whole pipe system. To start with, it is beneficial to understand the difference between a straight pipe and a pipe spool. A pipe is a straight and longitudinal shaped tube where fluid mass is transported. However, a pipe spool is a complex shaped tube which consists of different segments. In modern engineering applications, pipe spools are used near everywhere for the transportation of desired matters. The spool components can be divided into the sized straight pipes and the fittings. Moreover, fittings can also be classified as flanges, tees, and elbows. These different components are used extensively for miscellaneous demands. A pipe spool system must meet some compulsory necessities to yield an efficient flow of the fluid mass. Therefore a complex spool pipe system must have high flexibility, cycle life, pressure rating, chemical, and corrosion resistance. For instance, pipe spools are commonly used in petroleum refineries and crude oil transportation lines. A sharp curvature of a pipeline can change the flow type of petroleum from laminar to turbulent. Therefore, the turbulent flow of petroleum may cause erosion and corrosion in the system. These erosion and corrosion problems can be identified from the horseshoe-shaped crevices. Since these crevices are the removal of the material from the surface, they can cause leakages from the system and can be detrimental to the petroleum transportation pipeline. Hence, a proper material and component selection for the desired pipe spool application is crucial for the safety of the system. The classification of the spool applications can be classified into two sections. The first section is the spool segments that can be used separately or together for desired applications. The second section is the usage areas of the piping spool systems.
- Applications of Spool Components
A pipe spool system is composed of various components with different shapes and sizes. Hence, the usage density of some components can be higher than another component for the desired application. The spool components are generally the flanges, tees, and elbows and their usage differs for different applications.
Usage Areas of Flanges
The most used flange types according to ASME 16.5 are welding neck, slip-on, socket weld, lap joint, threaded and blind flanges. The welding neck flanges are used to cancel or reduce the turbulent flow in a system. The turbulent flow in a pipeline can cause corrosion that can be deleterious for the system. Moreover, for applications that require high durability for the stress caused by the flowing substance, a welding neck flange is proper to use. This type of flange distributes the stress equally through the inner walls of the pipe which prevents any possible flaws or cracks due to the excessive stresses. The slip-on flanges are favorable for low-cost applications. The pipe system does not require perfect cutting since the easier alignment of the slip-on flanges. Another type of flange is the socket weld flanges and they used in applications where the pressure of the flow is relatively lower than the other types. However, the socket weld flanges are not appropriate for the applications where a highly corrosive product is transported. Since these types of flanges have a groove in their body, leakage of the liquid substance through these shelters may cause corrosion. In contrast to socket weld flanges, lap joint flanges are favorable for applications where a highly corrosive product is carried. Hence, the deficiency of the contact between the liquid and the lap joint flange makes possible the usage of low carbon steel material. The other group of flanges is the threaded flanges. The main advantage of these types of flanges is the fixing ability of flanges to the main pipe system without any need for welding. The final flange group is the blind flanges. Blind flanges are used where the flow of the fluid is desired to get stopped. Since this task, blind flanges are used in high-pressure applications.
Usage Areas of Tees
Tees are usually used for changing the flow direction of the fluid. Tees can also change the flow pressure of the matter in the pipeline system. Tees can be divided into two groups as butt-welded tees and socket-welded tees. The butt-welded tees are used as straight fittings or reducer fittings. The reducer types of these tees are usually common for applications where the flow pressure is lowered by the system. The socket-welded tees are favorable for high-pressure applications.
Usage Areas of Elbows
Elbows are also used to alter the flow direction in the system. Hence, the angle of an elbow may differ for various applications. Elbows can be divided into two main groups by considering the change rate of the flow. These two groups are named as long radius (LR) and short radius (SR) elbows. This classification is made according to the calculated distance between the centerline of one ending face to another ending face. Therefore, this distance is called ‘center to face’ distance and determines the bending angle of the elbow. This bending angle is crucial for the applications where the system is suffered from elevated pressures.
Fig 1. Short and Long radius elbows. Retrieved from Difference Between A Pipe Elbow And A Pipe Bend – China Steel Pipes, Flanges, Pipe Fittings Manufacturer. (2020). 9 February 2020, https://www.steeljrv.com/difference-between-a-pipe-elbow-and-a-pipe-bend.html
2. Usage Areas of Pipe Spools
The pipe spools are used almost every industrial application since they are pretty dexterous. The particular segments of the spool systems can be arranged in various sizes and shapes for the target application area. Therefore, the most common application areas of the pipe spools can be divided into; domestic applications, industrial applications (factories), medical applications and construction applications.
Domestic Applications: Most of the domestic applications use steel piping systems since they are mechanically durable and they have high corrosion resistance. Materials for the spool pipes are chosen as stainless steel for domestic applications (household applications). The whole plumbing system of a house consists of stainless steel pipes and spools.
Industrial Applications: The energy sources and some raw materials are transported via using complex spool systems. The factories usually produce by-products such as waste gases and liquids. These waste gases and liquids must be removed from the production area. Hence, the removal of these substances is also done by piping systems. Some complicated spool systems are preferred in industries where limitation of space creates difficulties. Moreover, extremely long pipeline systems are also used for the transportation of energy sources (petroleum, natural gas, etc.). These extremely long pipeline systems have various spool segments in different sizes and shapes.
Medical Applications: The simple pipe systems are utilized even in surgical and dental applications. The biocompatibility of the used pipe is the most important criteria in medical applications. Hence, a compatible steel pipe is used for healing the fractured bones or medical machining applications.
Constructional Applications: One of the most common usage areas of the pipe spools are the construction sites. The desired pipe material is generally chosen as steel for high strength. When the base of the construction is too weak to carry the building, steel pipes are used as support elements for the construction. In some architectural works, only a complex spool system is utilized for the construction. The pipe systems are also used for the construction of ships and oil refineries.