What Is a Blank Flange?
A blank flange, also known as a blind flange, is a type of pipe flange used to terminate the flow of fluids in piping systems. It serves as a stopper by sealing the end of a pipe and is essential for pressure testing, maintenance, or future expansions of piping networks. Unlike other flanges, a blank flange does not have a center opening for fluid passage but is equipped with boltholes for securing it to a mating flange with a gasket in between to ensure a leak-proof seal.
Uses of Blank Flanges
Blank flanges are versatile components used across various sectors, including oil and gas, chemical processing, and water treatment plants, for temporary or permanent closure of pipeline systems. They facilitate safe maintenance and inspection activities by isolating sections of the network and preventing contamination and leaks.
Principle of Blank Flanges
The effectiveness of a blank flange lies in its ability to provide a secure and tight seal at the end of a pipeline. When installed, a gasket is placed between the blank flange and its mating flange, and the assembly is then fastened with bolts and nuts. This setup prevents any fluid from bypassing the closed section, ensuring the integrity of the system under various operational conditions, including high-pressure and high-temperature environments.
Types of Blank Flanges
Selection criteria for blank flanges include the nominal diameter, pressure rating, material, and gasket seat type, tailored to the specific needs of the piping system. The nominal diameter matches the piping system’s dimensions, ensuring compatibility and a proper fit. The pressure rating corresponds to the system’s maximum operating pressure, with materials chosen based on their resistance to the conveyed fluid’s corrosive or thermal properties.
- Nominal Diameter: Matches the piping to ensure compatibility.
- Nominal Pressure: Corresponds to the system’s maximum operating pressure.
- Material: Selected based on resistance to corrosion and temperature.
- Gasket Seat: Includes full face (FF), flat face (RF), fitted (MF), and groove (TG), selected based on the type of gasket and sealing requirements.
Other Information on Blank Flanges
Standards governing blank flanges ensure uniformity and safety across applications, with common standards including ASME/ANSI B16.5 and ISO 7005-1. Gasket selection is crucial for achieving a reliable seal, with options like spiral-wound gaskets for high-temperature and high-pressure applications, joint sheet gaskets for general use, and ring joint gaskets for specialized industry standards.