Different Types of Flanges in Piping System and Threaded Flanges

Flanges are essential components in piping systems that allow for easy assembly and disassembly of various sections. They are primarily a connector that connects pipes, valves, pumps, and other equipment, thus ensuring a secure and leak-proof connection.

There are different varieties of flanges used in piping systems. Their selection depends on various factors such as temperature, pressure, and pipe size.
Industrial flanges are of different types as used in piping systems described below:

Weld Neck Flanges

Weld neck flanges are extensive in high-pressure and high-temperature piping units. Such systems have a long-tapered hub that connects to the pipe and a neck that goes through the flange.

Weld neck flanges are welded to the pipe providing excellent strength and stability and thus preferred for critical applications, such as nuclear and petrochemical industries.

Slip-On Flanges

Slip-on flanges are an extensively used type of flange in low-pressure piping systems. They have a flat face with a bore size that matches the pipe’s outside diameter.

Slip-on flanges are easy to install and provide excellent alignment for the piping system. They are cost-effective and even suitable for non-critical applications.

Socket Weld Flanges

Socket weld flanges are similar to slip-on flanges and thus have a socket to fit the pipe. They provide better strength than slip-on flanges. These flanges are apt for high-pressure piping systems welded to the pipe to ensure a leak-proof connection.

Lap Joint Flanges

Lap joint flanges are integral to the piping systems where frequent disassembly is necessitated. They consist of 2 parts – a stub end and a loose backing flange.

The stub end is welded to the pipe, and the backing flange slides over it. Lap joint flanges are convenient to assemble and disassemble and provide excellent flexibility.

Blind Flanges

Blind flanges help seal the end of a piping system. They have no bore and are bolted to the pipe’s end. They provide a leak-proof seal. Blind flanges are commonly used in pressure vessels and tanks where periodic cleaning or inspection is required.

Orifice Flanges

Orifice flanges are used in piping systems to measure the flow rate of liquids and gases. They have a concentric or eccentric bore that restricts the flow path. Orifice flanges are integral to the oil and gas industry and chemical processing plants.

Spectacle Blind Flanges

Spectacle blind flanges are standard in piping systems where the flow needs to be diverted or blocked. They consist of two metal discs with a hole in the center aligned or rotated to block or allow the flow. Spectacle blind flanges find their usage in the oil and gas industry and chemical processing plants.

Threaded flanges

Threaded flanges are flange connection that utilizes a threaded connection between two pipes or fittings. These flanges are used in piping systems where frequent disassembly is required, such as in chemical plants, refineries, and power generation facilities.

In addition, threaded flanges are widespread in low-pressure applications where the pipe’s pressure rating is less than 600 psi.

Threaded flanges are designed to be screwed onto the pipe or fitting, creating a tight and secure seal. The threaded portion of the flange is typically machined with a tapered thread to ensure a tight seal. The tapered thread design allows the flange to be tightened as the threads are engaged,

compressing the gasket between the flange faces and creating a secure seal. Depending on the specific application, threaded flanges are designed from materials such as stainless steel, carbon steel, or other alloys.

Benefits of using threaded flanges

One of the benefits of using threaded flanges is their ease of installation. Unlike other flanges, such as weld necks or slip-on flanges, threaded flanges do not require welding or special installation tools

. Instead, the flange can be screwed onto the pipe or fitted using a pipe wrench or similar tool.

It makes threaded flanges ideal for applications where frequent disassembly is required as they can be easily removed and reinstalled without the necessity of any specialized equipment.

Another benefit of threaded flanges is their versatility. Threaded flanges can be used in diverse applications, from low-pressure piping systems to high-temperature and high-pressure applications.

In addition, they are available in different sizes and materials, thus making it easier to find the appropriate flange for any application.

Drawbacks of threaded flanges

Despite their many benefits, threaded flanges do have some limitations. One of the primary limitations of threaded flanges is their lower pressure rating comparable to other varieties of flanges. Because the threaded connection is not as strong as a welded connection,

threaded flanges are typically limited to low-pressure applications. Additionally, threaded flanges may be more prone to leakage than other flanges, as the threaded connection can be more susceptible to vibration and other forces that can cause the threads to loosen over time.

How to minimize the risks associated with threaded flanges?

To minimize the risk of leakage, ensuring that the threaded flange is installed correctly is significant. It includes using the correct torque specifications when tightening the flange and ensuring that the threads are clean and free of debris before installation.

In addition, using the appropriate gasket material for the specific application is significant, as the gasket plays a critical role in ensuring a tight seal between the flange faces.

Following proper installation procedures and using the correct materials, threaded flanges can provide a secure and leak-free connection for many years of service.

Flanges are an essential component in piping systems, and their selection depends on various factors such as temperature, pressure, and pipe size.

Therefore, selecting the appropriate flange type is critical for the correct functioning of the piping system.

This article discussed the different types of flanges used in piping systems, their advantages, and their applications. In addition, the threaded flanges are explained in detail.

A thorough understanding of flanges can help select the appropriate flange for your piping system, ensuring a safe and efficient operation.