Blind flanges and slip-on flanges have the following key differences:

Function and Application:

Blind flanges are used to close off the end of a pipe, pressure vessel, or equipment nozzle. They provide a sealed barrier and are commonly used in applications where the piping system needs to be isolated for maintenance, testing, or to prevent flow in a particular section. For example, in a chemical processing plant, blind flanges might be used to block off a section of pipe during equipment repair or when a particular process line is not in use.

Slip-on flanges are designed to slide over the end of a pipe and are then welded in place. They are typically used in low-pressure applications and are popular in general plumbing and industrial piping systems where quick and easy installation is required. For instance, in a building's water supply or drainage system, slip-on flanges might be used to connect sections of pipes.

Design and Structure:

Blind flanges have a solid, flat face with no bore or opening in the center. They are usually thicker and heavier than slip-on flanges due to their role in providing a strong seal and withstanding pressure from only one side. The thickness of a blind flange is designed to handle the pressure exerted on it when the pipe system is in operation or during testing conditions.

Slip-on flanges have a bore that matches the pipe diameter and a raised face or flat face depending on the application requirements. They have a relatively thinner body compared to blind flanges as they rely on the welding around the circumference of the pipe to provide strength and stability. The design allows them to be easily slipped onto the pipe before welding.

Installation Process:

Installing a blind flange requires bolting it firmly onto the mating flange or pipe end using a series of bolts and gaskets. The bolts are tightened to create a leak-proof seal. Due to their heavy-duty nature, proper torque must be applied during installation to ensure a secure connection.

Slip-on flanges are installed by simply sliding them over the pipe end and then welding the flange to the pipe. The welding process is crucial to ensure a strong and durable connection. Welding can be done using various methods such as shielded metal arc welding or gas tungsten arc welding depending on the material and application requirements.