Seamless Threaded Pipe Fittings

The sealing of Seamless Threaded Pipe Fittings is the key to ensuring the normal operation of pipeline systems.Its sealing principle is mainly based on the matching of threads,the filling of sealing materials,and the deformation and compression of fittings.The following is a detailed introduction for you:

Thread fit seal

Mechanical bite of threads:Seamless threaded fittings achieve preliminary sealing through mechanical bite between threads.The common types of threads include triangular threads,such as metric triangular threads(with a profile angle of 60°)and imperial triangular threads(with a profile angle of 55°).During the tightening process,the profiles of the internal and external threads match each other,forming multiple sealing surfaces.When the pipe fitting is tightened,the tooth side of the thread is in close contact,which can prevent fluid leakage from the thread gap.For example,in some low-pressure gas transmission pipelines,a certain degree of sealing can be achieved solely through mechanical interlocking of threads.

The influence of thread accuracy:The accuracy of threads is crucial to the sealing effect.High precision thread machining can ensure that the dimensional tolerance,tooth profile accuracy,and surface roughness of the threads meet the requirements,making the fit between threads tighter.If the thread accuracy is insufficient,it will lead to uneven thread clearance and easy leakage.For example,in some hydraulic systems that require high sealing,high-precision threaded fittings are needed to ensure the sealing of the system.

Sealing material assisted sealing

Sealing tape:The commonly used sealing tape is polytetrafluoroethylene(PTFE)sealing tape,which has good chemical stability,corrosion resistance,and flexibility.When installing seamless threaded fittings,wrap the sealing tape around the thread.When the fitting is tightened,the sealing tape is squeezed into the thread gap,filling the small defects and gaps on the thread surface and forming an additional sealing layer.The sealing tape can also provide lubrication,reduce friction between threads,and facilitate the installation and disassembly of pipe fittings.For example,in the installation of household water pipes,PTFE sealing tape is often used to wrap around the pipe threads to prevent water leakage.

Sealing glue:Sealing glue is usually a material with viscosity and elasticity,such as anaerobic sealing glue,silicone sealing glue,etc.After applying sealant on the threads of the pipe fittings,the sealant will fill and solidify in the gap between the threads,forming a continuous sealing layer.Sealing glue can adapt to the unevenness of the thread surface,enhance the sealing effect,and also prevent thread loosening and corrosion.For example,in the oil pipe connection of a car engine,anaerobic sealant is used to ensure the sealing and reliability of the oil pipe.

Deformation and compression sealing of pipe fittings

End sealing:Some seamless threaded fittings achieve sealing by deforming and compressing the ends of the fittings during connection.For example,some pipe fittings are designed with sealing surfaces at the ends.When the pipe fittings are tightened,the sealing surfaces press against each other,causing deformation at the ends of the pipe fittings and forming a tight seal.This sealing method is usually used in high-pressure,high-temperature,or extremely high sealing requirements,such as pipeline connections in the petrochemical industry.

Gasket sealing:Using gaskets at the connection of pipe fittings is also a common sealing method.Gaskets are usually made of materials such as rubber,metal,graphite,etc.,which have good elasticity and sealing performance.When the pipe fittings are tightened,the gasket is compressed between the two sealing surfaces,filling the uneven sealing surfaces and preventing fluid leakage.For example,in seamless threaded fittings connected by flanges,gaskets play an important sealing role.