alwepo, Flanges are critical components in the world of piping systems, serving as the linchpin that connects pipes, valves, pumps, and other vital elements, creating a secure and sealed infrastructure. These versatile mechanical joints are secured through welding or threading and rely on gaskets to ensure a reliable seal.
In fact, flanges are the second most widely used method for joining pipes, right after welding. In this comprehensive guide, we will delve into seven different types of flanges extensively used in piping systems, offering insight into their unique features, applications, and benefits.
1. Slip-on Flange
Slip-on flanges are a versatile type of flange used to connect pipes and fittings. They secure themselves to a pipe by employing two fillet welds – one on the inside and another on the outside of the flange. These flanges are specifically designed for ease of installation and are known for their convenient sliding-over-pipe feature. The bore size of a slip-on flange is typically larger than the outer diameter of the connecting pipe, requiring the pipe to slide inside the flange for connection.
Applications: Slip-on flanges are widely employed in piping systems that transport fluids. They are preferred for their simplicity in installation, making them a practical choice for pipelines carrying various liquids.
2. Threaded Flanges
Threaded flanges share similarities with slip-on flanges but have a distinctive feature – they are bored to match the inner diameter of the connecting pipe. This unique characteristic allows threaded flanges to be efficiently threaded onto the pipe, resulting in a time-efficient and cost-effective solution, especially for smaller diameter piping systems. They are also essential in areas with a high risk of explosions where traditional welding methods may pose safety concerns.
Applications: Threaded flanges are ideal for smaller diameter piping systems, such as those used in industries with explosion-prone environments. Their ease of installation and adaptability make them a suitable choice in these conditions.
3. Weld Neck Flange
Weld neck flanges, sometimes referred to as high-hub or tapered hub flanges, are designed to reduce pressure at the bottom of the flange. These flanges are best suited for pipes that operate under varying temperature and pressure conditions. A key feature of weld neck flanges is the presence of a circular fitting with a protruding edge around the bore, which ensures a precise match with the pipe’s diameter.
Applications: Weld neck flanges are commonly used in applications where high and low-temperature conditions, as well as high-pressure requirements, are present. They find extensive use in industries that demand a secure and reliable connection.
4. Socket Weld Flanges
Socket weld flanges offer an alternative to slip-on flanges with the advantage of requiring only a single fillet weld, executed on the exterior of the flange. The design of socket weld flanges ensures that the pipe is correctly positioned during the welding process. Furthermore, the small gap between the pipe and the socket serves to minimize residual pressure as the metal solidifies during welding.
Applications: Socket weld flanges are typically used in compact, high-pressure pipe systems, particularly those handling non-corrosive liquids. Their design minimizes the risk of residual pressure build-up during welding, making them suitable for such applications.
5. Blind Flange
Blind flanges are unique in that they lack a bore. Their primary function is to block the flow of fluids by sealing pipe, valve, or vessel ends. These flanges are engineered to withstand substantial mechanical stress originating from system pressure and bolting forces. They are often employed to close off unused nozzles on a tank, serving a vital role in pressure testing or scenarios where not all nozzles are in use.
Applications: Blind flanges are the preferred choice when it comes to sealing pipe or vessel ends. Their ability to endure high mechanical stress and provide a secure seal, even under high-temperature conditions, makes them indispensable for various applications.
6. Lap Joint Flange
Lap joint flanges feature a flat face and must be used in conjunction with a stub end. Unlike slip-on flanges, lap joint flanges have a radius where the flange face meets the bore. This design allows the flanged part of the stub end to fit seamlessly. Bolts are used to attach lap joint flanges to the stub end, enabling them to slide over the pipe. One significant advantage of lap joint flanges is their cost-effectiveness, as they can be constructed with lower-quality materials compared to the stub end.
Applications: Lap joint flanges are a cost-effective choice, particularly for stainless steel or nickel alloy pipelines. Their design allows for cost savings while maintaining the integrity of the pipeline system.
7. Long Neck Weld Flanges
Long neck weld flanges are a preferred choice in applications that involve high-pressure and high-temperature conditions, particularly in industries like oil and gas. These flanges resemble standard weld neck flanges but possess a much longer neck, often referred to as a tapered hub. This extended neck functions as an extension bore, offering unique advantages in specific scenarios.
Applications: Long neck weld flanges are commonly used in the process of anchoring water mains or gas sources that feed into a larger network of pipes. They find applications in diverse settings, including manufacturing facilities and apartment buildings, where their extended neck proves to be beneficial.
Additional Flange Types
1. Slip-on Flange
Slip-on flanges are a versatile type of flange used to connect pipes and fittings. They secure themselves to a pipe by employing two fillet welds – one on the inside and another on the outside of the flange. These flanges are specifically designed for ease of installation and are known for their convenient sliding-over-pipe feature. The bore size of a slip-on flange is typically larger than the outer diameter of the connecting pipe, requiring the pipe to slide inside the flange for connection.
Applications: Slip-on flanges are widely employed in piping systems that transport fluids. They are preferred for their simplicity in installation, making them a practical choice for pipelines carrying various liquids.
2. Threaded Flanges
Threaded flanges share similarities with slip-on flanges but have a distinctive feature – they are bored to match the inner diameter of the connecting pipe. This unique characteristic allows threaded flanges to be efficiently threaded onto the pipe, resulting in a time-efficient and cost-effective solution, especially for smaller diameter piping systems. They are also essential in areas with a high risk of explosions where traditional welding methods may pose safety concerns.
Applications: Threaded flanges are ideal for smaller diameter piping systems, such as those used in industries with explosion-prone environments. Their ease of installation and adaptability make them a suitable choice in these conditions.
3. Weld Neck Flange
Weld neck flanges, sometimes referred to as high-hub or tapered hub flanges, are designed to reduce pressure at the bottom of the flange. These flanges are best suited for pipes that operate under varying temperature and pressure conditions. A key feature of weld neck flanges is the presence of a circular fitting with a protruding edge around the bore, which ensures a precise match with the pipe’s diameter.
Applications: Weld neck flanges are commonly used in applications where high and low-temperature conditions, as well as high-pressure requirements, are present. They find extensive use in industries that demand a secure and reliable connection.
4. Socket Weld Flanges
Socket weld flanges offer an alternative to slip-on flanges with the advantage of requiring only a single fillet weld, executed on the exterior of the flange. The design of socket weld flanges ensures that the pipe is correctly positioned during the welding process. Furthermore, the small gap between the pipe and the socket serves to minimize residual pressure as the metal solidifies during welding.
Applications: Socket weld flanges are typically used in compact, high-pressure pipe systems, particularly those handling non-corrosive liquids. Their design minimizes the risk of residual pressure build-up during welding, making them suitable for such applications.
5. Blind Flange
Blind flanges are unique in that they lack a bore. Their primary function is to block the flow of fluids by sealing pipe, valve, or vessel ends. These flanges are engineered to withstand substantial mechanical stress originating from system pressure and bolting forces. They are often employed to close off unused nozzles on a tank, serving a vital role in pressure testing or scenarios where not all nozzles are in use.
Applications: Blind flanges are the preferred choice when it comes to sealing pipe or vessel ends. Their ability to endure high mechanical stress and provide a secure seal, even under high-temperature conditions, makes them indispensable for various applications.
6. Lap Joint Flange
Lap joint flanges feature a flat face and must be used in conjunction with a stub end. Unlike slip-on flanges, lap joint flanges have a radius where the flange face meets the bore. This design allows the flanged part of the stub end to fit seamlessly. Bolts are used to attach lap joint flanges to the stub end, enabling them to slide over the pipe. One significant advantage of lap joint flanges is their cost-effectiveness, as they can be constructed with lower-quality materials compared to the stub end.
Applications: Lap joint flanges are a cost-effective choice, particularly for stainless steel or nickel alloy pipelines. Their design allows for cost savings while maintaining the integrity of the pipeline system.
7. Long Neck Weld Flanges
Long neck weld flanges are a preferred choice in applications that involve high-pressure and high-temperature conditions, particularly in industries like oil and gas. These flanges resemble standard weld neck flanges but possess a much longer neck, often referred to as a tapered hub. This extended neck functions as an extension bore, offering unique advantages in specific scenarios.
Applications: Long neck weld flanges are commonly used in the process of anchoring water mains or gas sources that feed into a larger network of pipes. They find applications in diverse settings, including manufacturing facilities and apartment buildings, where their extended neck proves to be beneficial.
Flanges are indispensable components of piping systems, ensuring functionality and safety. Each type of flange has its unique attributes and applications, catering to specific needs and conditions. Understanding these various flange types is essential for anyone involved in piping system design, construction, or maintenance.
