Selection and Installation Precautions of NPT Threads

Product catalog summary

Selection and Installation Precautions of NPT Threads

Introduction
NPT (National Pipe Threads) are widely used in the oil industry due to their excellent sealing properties. They feature a 1° 47' tapered thread with a 60° thread angle, as per American standards, and are referenced in Chinese standards GB/T12716.

NPT vs. G Threads
G threads, or tapered pipe threads, require O-rings or gaskets for sealing, as they do not have interference between the thread flanks, crests, and roots. In contrast, NPT threads, being cone taper, offer superior sealing performance and are preferred in high-pressure applications.

Sealant Considerations
Sealants are crucial for NPT threads to prevent fluid leakage and reduce thread galling. Key considerations include:

Choosing the appropriate width of sealant.
Avoiding excessive winding circles to prevent gaps that compromise sealing.

Fitting Accuracy
Accurate fitting of NPT threads is essential. For example, the Jiwei Vibrating Rod Level Switch with a 1" NPT thread requires precise dimensions and minimal fault tolerance. The outer diameter of the extension tube is 29mm, while the 1" NPT female thread has specific pitch diameters. Post-welding, polishing is necessary to ensure consistency through the threaded hole.

Quality Assurance
Each threaded connection undergoes inspection with a pitch gauge to verify thread pitch before factory dispatch.

Catalog excerpts

Selection and Installation Precautions of NPT Threads-1

EiU JIUJCI Selection and Installation Precautions of NPT Threads Due to the good sealing effect, thread connection is one of the commonly used process connections in automation instruments. Threads are according NPT (National Pipe Threads) as American Standard which is the most used in the oil industry, which has a 1° 47' tapered thread with a 60° thread angle, Chinese National standards can be found in GB/T12716. NPT (also known as ASME B1.20.1) Characteristics ■ Tapered thread (1° 47') ■ Truncation of roots and crests are flat ■ 60° thread angle ■ Pitch is measured in threads per inch G threads, or tapered pipe threads, belong to non-sealed pipe threads, which generally rely on O-rings or gaskets to achieve ideal sealing effects. Because the threads of the mating fittings are parallel to each other, there is no interference between the flanks, crests, and roots. Consequently, the seal must be made with a gasket, O-ring, or some metal to metal contact.

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Selection and Installation Precautions of NPT Threads-2

NPT threads belong to cone taper, the sealing performance is better than G threads. NPT threads are mainly used in applications with high pressure, high connection strength, and high sealing requirements, so the accuracy and the processing difficulty are also strict. For a Jiwei G thread connection product, a gasket will be provided for customer installation. Gasket 深圳计为自动

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Selection and Installation Precautions of NPT Threads-3

The selection of NPT threaded connections and the sealant are also carefully considered. Tapered pipe threads always need a sealant to seal system fluids and reduce the potential for galling of the threads. Attention should be paid to the use of sealant: 1. Choose a suitable width of sealant, rather than the wider the better. 2. The appropriate number of winding circles is better than the more. The sealant with a large number of winding circles is prone to gaps between each layer, which cannot tightly fit with the thread and instead affects the sealing effect. In addition to the need to pay attention...

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Selection and Installation Precautions of NPT Threads-4

each threaded connection undergoes inspection with a pitch gauge to determine the thread pitch. Jiwei 1 "NPT process connection Jiwei Vibrating Rod Level Switch with 1 "NPT thread

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