NPT, Pt and G are all pipe threads. NPT is the abbreviation of national pipe thread, which belongs to 60 degree taper pipe thread of American Standard, and is used in North America. Refer to GB / t12716-1991pt is pipe thread Thread is the abbreviation of 55 degree sealed tapered pipe thread. It belongs to Wyeth thread family and is mostly used in Europe and the British Commonwealth. It is commonly used in water and gas pipe industry, and the taper is 1:16. Refer to GB / t7306-2000 for national standard

G is a 55 degree non threaded sealed pipe thread, belonging to Wyeth thread family. The mark g represents cylindrical thread. The standard can be consulted in GB / t7307-200. In addition, the 1 / 4, 1 / 2 and 1 / 8 marks in the thread refer to the diameter of the thread size, and the unit is inch. Insiders usually call the thread size by minute. One inch is equal to 8 points, and 1 / 4 inch is 2 points.

And so on. G is the general name of pipe thread. The division of 55 and 60 degrees belongs to functional, commonly known as pipe circle. That is, the thread is made of a cylindrical surface. ZG is commonly known as pipe cone, that is, the thread is made of a round cone surface. The general water pipe joints are like this. The old domestic thread mark is RC The external thread is r, the metric thread is represented by pitch, and the American British thread is represented by the number of threads per inch. This is a bigger difference between them. The metric thread is 60 degree equilateral profile, the British thread is 55 degree isosceles profile, and the American thread is 60 degree. Metric screw thread uses metric unit, American and British screw thread uses English unit.