The difference between the NPT, PT, G of thread

At the sight of mid-december, you know who is the standard of screw thread, since mid-december, is Chinese & other; Taper pipe & throughout; Pinyin ', therefore mid-december, thread taper pipe threads, its tooth shape is 55 degrees. G is also standard in our country, G is & other; Tube & throughout; The first letter of hanyu pinyin. Thread is so G & other; Pipe thread & throughout; 。 Taper pipe thread is straight, no belt, this is the difference between it and mid-december, thread. The NPT is National ( 美国) National standards for GB/T12716 - 1991. National standards for GB/T7306 - 2000. National standards for GB/T7307 - 2001. Inline people usually call thread sizes, points 1 & other; Equal to eight points, 1/4 & throughout; G is generally referred to as the pipe thread ( Guan) , 55, 60 degrees division belongs to functional, commonly known as round tube. The thread by a cylinder. Mid-december, commonly known as the tube cone, the thread surface is processed by a cone, the general water connection is such, national standard labeling for Rc, with metric thread pitch, the inch thread used to represent the number of thread within per inch, which is the biggest difference between them and metric thread is 60 degrees equilateral tooth type, inch thread tooth type is isosceles 55 degrees, American thread 60 degrees. Code R said conical external thread, Rc said thread in the cone, the Rp said cylindrical internal thread R - taper pipe external thread ( The old code mid-december,; KG） 。 RC - taper pipe threads ( The old code mid-december,; KG） Metric thread with metric unit, the inch thread used English unit. Pipe thread is mainly used for pipe connection, its internal and external thread cooperate closely, which has two kinds of straight tube and cone tube. Nominal diameter refers to the connection pipe diameter, apparently thread diameter larger than the nominal diameter. A quarter, 1/2, 1 / nominal diameter is 8 inch thread, the unit is inches.