How to choose fittings

When we buy fittings, the first consideration should be the material and model of the fittings. But it is not enough to consider these alone, and to find the right size and type of thread.

Intubation sizes are available in both imperial and metric systems. The commonly used British sizes are 5/32, 1/4, 5/16, 3/8 and so on. Then the corresponding metric sizes are 4mm, 6mm, 8mm, 10mm and so on.

Thread commonly used G thread, R thread and NPT thread.

G thread refers to the non-threaded sealing pipe thread: tooth Angle is 55 degrees, with no sealing, only in the pipeline to connect the role, with the help of the sealing ring can be used for low pressure pipe under static load. The top and bottom of the teeth are rounded. In addition, the 1/4, 1/2, and 1/8 marks on the thread refer to the diameter of the thread dimensions in inches. An inch is 8 cents, a quarter of an inch is 2 cents, and so on.

R thread refers to the pipe thread sealed with thread, tooth Angle is 55 degrees, after rotation, sealing. The top and bottom of teeth are rounded. There are two types: 1) cylindrical internal thread/tapered external thread, used for low pressure static load, such as water and gas pipes; 2) Taper internal thread/taper external thread for high pressure and impact bearing applications.

NPT thread is a United States standard 60 degree tapered pipe thread with a dividing line in the middle.

The G thread seal ring is also divided into several materials.
PTFE, white, is made of tetrafluoroethylene by polymerization of polymer compounds, has excellent chemical stability, corrosion resistance, sealing, high lubrication non-viscosity, electrical insulation and good anti-aging endurance. The working temperature is generally -10-200℃, generally suitable for the medium is air working environment.

Viton, green, has high chemical stability, high temperature resistance and silicone rubber, can be said to be the best elastomer. The working temperature is generally -10-200℃, high temperature resistance, corrosion resistance, used for the medium is water and liquid working environment.

NBR, black, has good water resistance, air tightness and excellent bonding performance, but also widely used in making a variety of oil resistant rubber products, a variety of oil resistant gaskets, the working temperature is generally -5-85℃.

Therefore, when determining a product, it is not only necessary to know the model number, but also all kinds of other data that need to be known. It is also critical to determine the size and type of thread you need in order to find a product that is more suitable for you.

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