Introduction and Uses of Blind Flange
Date:2025-03-27View:117Tags:SSAW steel pipe,LSAW steel pipe,Epoxy pipe
1. Introduction to Blind Flange
Blind Flange, also known as flange cover or dead flange, is a flange without a central through hole. It is mainly used to close the end of a pipeline, valve or pressure vessel to prevent the flow of media or provide maintenance isolation.
2. Main features
No center hole: Unlike ordinary flanges, blind flanges have no holes in the middle and completely seal the pipeline or equipment port.
Removable design: easy to install and disassemble, suitable for occasions requiring temporary closure or maintenance.
High sealing: usually rubber gaskets, metal spiral wound gaskets or polytetrafluoroethylene (PTFE) gaskets are used to ensure reliable sealing.
Strong pressure bearing capacity: suitable for high pressure and high temperature conditions, such as petroleum, chemical, power and other industries.
3. Uses of Blind Flange
Blind flanges are widely used in the following scenarios of pipeline systems:
Pipeline plugging: Close at the end or branch of the pipeline to prevent medium leakage.
System isolation: Isolate some pipelines or equipment during maintenance to ensure safe operation.
Pressure test: Close the pipeline during pressure test or purging to check the system sealing.
Reserve spare interface: Reserve interface for future pipeline expansion and temporarily close it.
4. Classification of blind flanges
By standard: ANSI, DIN, JIS, GB (national standard) and other different standard specifications.
By sealing surface: flat surface (FF), raised surface (RF), ring joint surface (RTJ), etc.
By material: carbon steel (A105), stainless steel (304/316), alloy steel, etc.
5. Installation of blind flanges
During installation, ensure that the flange surface is clean and the gasket is placed correctly.
Bolts need to be tightened symmetrically and evenly to avoid leakage caused by uneven force.
In high-pressure systems, it is recommended to use metal ring gaskets or high-strength bolts.
6. Blind flange vs. pipe cap
Comparison item Blind flange Pipe cap
Structure Flange type, removable Welding or threaded fixing
Applicable pressure High pressure, high temperature Medium and low pressure
Maintenance Convenient disassembly and maintenance Need cutting or welding replacement
Cost High Low
7. Application industry
Petrochemical industry: used for isolation of reactors and pipeline systems.
Power industry: boiler and steam pipeline sealing.
Water treatment: pump and valve system maintenance isolation.
Pharmaceutical/food: sanitary stainless steel blind plate is used for sterile pipelines.
8. Summary
Blind flange is an important sealing element in the pipeline system, suitable for high-pressure sealing, maintenance isolation and other scenes. It has the characteristics of high sealing, removable, strong pressure resistance, etc., and is widely used in petrochemical, power, water treatment and other industries. Correct selection and installation can ensure safe and stable operation of the system.
