stvvalves

  How to Identification of BSPP,BSPT, NPT threads? When you choose valves and pipe fittings , thread is a very important feature you have to consider. No matter how well the product is made, a wrong thread type will make it useless. You have to determine the thread type before you order. British Standard Pipe fittings are among the most popular of all foreign threads in the world today. These threads come in two versions: parallel (BSPP), and tapered (BSPT). The thread flank angle for both tapered and parallel British threads is 55°. Although BSP is a foreign thread, it isn’t actually metric. This is why it comes in Imperial sizes: 1/8, 1/4, 1/2, 3/4, etc. BSP parallel (BSPP) threads commonly seal via a 30° chamfer on the male thread to a 30° cone seat inside the female thread (swivel only). If it is a port application, an O-ring and washer, Elastomeric seal or a bonded washer are needed to achieve a proper seal for parallel threads. For tapered BSP threads (BSPT), a seal is accomp...

When you choose valves and pipe fittings, thread is a very important feature you have to consider. No matter how well the product is made, a wrong thread type will make it useless. You have to determine the thread type before you order. NPT Connections NPT (National Pipe Thread) seals are the most popular type of seal for pressure calibration systems in the U.S. and Canada. NPT male adapters have a taper thread that wedges into the female NPT adapter. They seal due to the “out of roundness principle” which means that the male stretches the female fitting until there is so much force that the connection can hold pressure. One of the challenges with this design is that if you connect stainless steel to stainless steel then over-tightening or poor lubrication can cause gauling and damage to the threads. Thread sealant is needed to seal but only 2 turns of thread sealant is required. Any more than that and the seal can leak around the thread sealant. Ralston Instruments has a wide var...