NPT Connections

William Sellers established the American standard for screws, bolts, and nuts in 1864, which later became known as the National Pipe Tapered Thread (NPT). His 60-degree thread angle, which early American clockmakers frequently employed, made the Industrial Revolution possible. Later on, these thread types evolved into the American National Standard.

Whitworth threads, with at least one thread tapered, were selected as self-sealing connection threads for pipes. This gave rise to the British Standard Pipe thread, commonly referred to as the BSP Taper or BSP Parallel thread. These days, the Whitworth thread—which is common around the world—is used to attach low carbon steel pipes.

In pressure calibration systems, NPT (National Pipe Thread) seals are the most commonly used type of seal. NPT male adapters have a taper thread that slides into the female adapter. The “out of roundness principle,” which claims that the male tugs the female fitting until the connection is strong enough to withstand pressure, is the reason they seal. One issue with this design is that when joining stainless steel to stainless steel, excessive tightness or insufficient lubrication can cause galling and damage to the threads. Thread sealant is required for sealing, however only two spins are required. If you use more, the thread sealant may seep through the seal.


Post time: Dec-06-2024