8 Types of Pipe Joints and Their Uses in Plumbing [Complete Guide]

Introduction

Types of Pipe Joints and Their Uses in Plumbing [Complete Guide]: – Pipe couplings in the water supply are important components of the plumbing system that allow several pipes to be connected. Pipe joints come in various shapes and sizes, and their selection is based on factors such as pipe size, material, and flow pressure. The pipe junction should be able to resist the pressure of each pipe.

Because longer pipeline sections tend to bend, joints strengthen the pipeline; joints should be carefully linked to ensure a tight seal is formed to avoid leaking. Pipe junctions are necessary for every piping system since a pipe network cannot have a continuous length of pipe.

The type of piping joint used in the piping system must be suitable for the pressure-temperature conditions of that line, and it should be chosen based on the joint tightness and mechanical strength under service conditions (including thermal expansion and contraction), as well as the fluid nature in terms of corrosion, erosion, flammability, and toxicity. This article will go through the many pipe joints and how they are used.

Methods for Joining Pipes

Pipes are joined using three methods: butt welding, socket welding, and screwed connections. Some others include brazed and soldered joints, grooved joints, flanged joints, and compression joints. Buttwelding is commonly used on pipes greater than 2 inches in diameter because it is cost-effective and creates leak-proof junctions. Bolted flange connections are used to connect large diameter pipes to flanged vessels or equipment or in situations where cleaning is required regularly. Threaded connections or socket welding can be used to link smaller diameter pipes.

Types of Pipe Joints

The following are many pipe joints found in a plumbing system.

1. Threaded Joint: ( Types of Pipe Joints )

Pipes are linked by screwing with the help of threads provided for each pipe in a threaded junction. One pipe has internal threads, while the other has threads on the outside. Threads are available on cast iron, copper, PVC, and G.I. pipes.

Threaded joints are available in sizes ranging from 6mm to 300mm. They cited low-temperature and low-pressure environments. Thermal expansion can cause joints to expand and leak in high-temperature locations. Threaded joints are simple to install, but they require regular maintenance.

2. Soldering Joint: ( Types of Pipe Joints )

Soldering is also similar to brazing, but, the only difference is in the case of soldering, the filler metal melts below 840oC. Soldering is also used to join copper and copper alloy pipes. Before proceeding to solder flux, the paste is applied to pipes and fittings to prevent them from oxidation from flame. Here also we require skilled workers for installation.

3. Brazed Joint: ( Types of Pipe Joints )

Brazing is the technique of joining pipes with molten filler material at temperatures exceeding 840 degrees Fahrenheit. Brazing is most commonly used to connect copper or copper alloy pipes. Tin, which has a strong affinity for copper, makes up most of the filler material. Because of its weak property, it is added to other materials such as nickel, bismuth, silver, and copper.

Parent metal should have a greater melting point than filler metal. Compared to other joints, the mechanical strength of a brazed joint is minimal. This sort of joint works well in places with a moderate temperature range.

4. Compression Joint: ( Types of Pipe Joints )

When pipes with plain ends are linked by placing fittings at their ends, the junction is referred to as a compression joint. Threaded fittings or couplings will be installed on the pipe ends to join them.

As a result, we may connect various materials and diameters of pipes in this scenario. However, the joints must be correctly installed to withstand flow pressure. Otherwise, they will fail and leak. Compression fittings come in various materials, and our choice of fittings may be based on our needs.

5. Flanged Joint: ( Types of Pipe Joints )

For high-pressure flows and large-diameter pipes, flanged joints are employed. They’re often utilized for threaded or plain end pipes. Two flange components are bolted together at the pipe junction to avoid leakage.

These are often built of cast iron, steel, or other strong materials that do not fail under high pressure. When exposed to high temperatures, bolts may break due to creep and lose grip; correct bolt installation is essential. They can also be used to repair pipes and perform routine maintenance.

6. Grooved Joint: ( Types of Pipe Joints )

The pipe ends of a grooved joint have grooved edges that an elastomer seal joins, and then ductile iron grooved couplings are utilized as a lock for the rubber seal. Bolts join the grooved couplings together. These joints are simple to put together and cost nothing.

Grooved joints provide strong pressure resistance while allowing for moderate axial movement due to thermal expansion. However, the elastomer seal may lose its strength in high-temperature areas, resulting in torsional failure. As a result, these can be used in regions where the temperature is moderated. Grooved joints are more easily detachable, making them the better choice for pipe maintenance.

7. Socket Welded Joint: ( Types of Pipe Joints )

Wherever there is a high risk of leakage in joints, socket welded joints are employed. Pipes are joined by inserting one into the other and welding around the junction, as seen below. This form of junction may be made with pipes of various sizes.

If the diameters of the pipes are similar, the needed fittings are employed. Welding is often less expensive than butt welding. Compared to butt-weld connections, socket welded joints have a lesser fatigue resistance. However, socket welded joints produce superior outcomes compared to other mechanical connections.

8. Butt Welded Joint: ( Types of Pipe Joints )

When the diameters of the pipes are the same, butt welding is used to connect them. It is the most frequent welding technique. Skilled professionals must install the joint. Large commercial and industrial plumbing systems frequently employ these connections.

Because of the smooth and continuous surface inside the joint, the butt weld offers exceptional joint strength and can withstand high pressure. Internal weld backing rings, which link the pipe with less filler material, are occasionally used to make butt weld joints most-effective time. However, these rings may collapse under extreme stress, and cracks may appear.

Where are Pipe Joint Fittings Used?

Pipe fittings used to link pipes include:

• Elbows are used to change the direction of a pipe by 45 or 90 degrees. They can have either a small or long radius.
• Reducing elbows reduces the line size while also changing the direction.
• Return pipe bends are used to alter the direction of a pipe by 180 degrees.
• Reducers are used to reduce the size of a pipe, such as when linking two bigger pipes together. They might be either concentric or eccentric
• connects flanges to pipe ends, valves, and other fittings.
• A tee creates a 90-degree branch from the main pipe. Straight tees, decreasing tees, and unequal tees are all options.
• A lateral tee, also known as a Wye tee, has a branch that is 45 degrees or another angle but not 90 degrees. This enables the joining of another pipe at that angle, which reduces friction and turbulence.
• A four-way pipe fitting having one input and three exits, or vice versa, is known as a cross.
• Pipe caps are used to cover the ends of pipes.
• In low-pressure small-bore pipework where pipe disassembly is common, unions are employed as flange substitutes.

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