What is the difference between NPT and NPS？

1. Definition

NPS (National Pipe Straight): NPS threads are straight and designed for pipes ranging from 1/8 inch to 12 inches. They ensure a tight seal when joined but are not 

NPT (National Pipe Taper): NPT threads are tapered and used for pipes from 1/16 inch to 24 inches. They also create a tight seal and are commonly utilized in plumbing and hydraulic systems, as well as in low-pressure applications like air compressors.

Comparison: Although NPT and NPS threads share the same angle, shape, and pitch (60° included angle with flat peaks and valleys), they are not interchangeable. NPT threads are tapered, while NPS threads are straight, meaning they do not seal properly when combined.

2.Thread advantage

(1) Here are some key details about NPT fittings:

Taper Rate:NPT threads have a taper rate of 1 inch per 16 inches of length.

Thread Angle: They feature a 60° thread angle with flat roots and crests.

Alignment and Sizing:NPT fittings do not align like many other fittings, and their nominal sizes do not directly correspond to the actual thread sizes. Due to these differences, fittings of different sizes cannot be assembled together.

Measurement:To measure the outside diameter of an NPT fitting, use a thread caliper.

(2) Here are some key details about NPS fittings:

Thread Design: NPS fittings feature straight, non-tapered threads.

Thread Angle: They have a 60° thread angle with flat roots and crests.

Size Range: NPS threads are used for pipes ranging from 1/8 inch to 12 inches in nominal size.

Sealing: NPS threads are designed to create a tight seal when the pipes are joined, but they are not intended for high-pressure applications.

Compatibility: NPS threads are not designed to seal with NPT threads despite having the same thread angle and pitch. The straight design of NPS threads contrasts with the tapered design of NPT threads, leading to improper sealing if mixed.

Variations: NPS fittings can come in different styles, such as NPSM (National Pipe Straight Mechanical), which has a mechanical seal with a straight thread and a 30° chamfer on the male connector. This style is often used in fluid power systems for its versatility and compatibility with other fittings.

(3).NPT and NPS threads share several similarities：

Thread Angle: Both have a 60° thread angle.

Pitch: They have the same pitch, meaning the number of threads per inch is identical.

Flat Peaks and Valleys: Both feature flat crests and roots.

Standardization: Both are part of the National Pipe Thread standards, used for pipe and fitting connections.

Despite these similarities, their tapered (NPT) versus straight (NPS) designs result in different sealing capabilities and applications.

(4).NPT and NPS threads are used in different applications：

NPT (National Pipe Taper): Commonly used in plumbing, hydraulic systems, and low-pressure applications like air compressors. The tapered design provides a tight seal, making it suitable for applications where leak-proof connections are crucial.

NPS (National Pipe Straight): Typically used in applications requiring a tight seal but not in high-pressure situations. It's often found in applications like venting and certain fluid handling systems. NPS threads are not ideal for sealing high-pressure systems due to their straight design.

(5).Why do we choose NPTF and NPSM thread hydraulic adapters from Ningji Yuli factory？

Firstly, the NPTF and NPSM threaded hydraulic adapters from Ningji Yuli factory have excellent pressure resistance performance. This is very important for hydraulic systems because they need to withstand a large amount of hydraulic pressure. If the adapter does not have sufficient pressure resistance, it will affect the efficiency of the entire hydraulic system.

Secondly, the NPTF and NPSM threaded hydraulic adapters from Ningji Yuli factory also have high quality stability. This is crucial for the stability and safety of hydraulic systems, as unstable adapter quality can lead to various system problems and even endanger personal safety.

Finally, the NPTF and NPSM threaded hydraulic adapters from Ningji Yuli factory also have excellent corrosion resistance. In hydraulic systems, we often need to use various liquids with different properties, which may corrode the adapter and affect the service life of the hydraulic system. The adapter of Ningji Yuli Factory adopts a special anti-corrosion coating, which can effectively resist the corrosive effect of various liquids, thereby ensuring the service life and safety of the system.

In summary, the NPTF and NPSM threaded hydraulic adapters manufactured by Ningji Yuli Factory have excellent pressure resistance, quality stability, and corrosion resistance, which can ensure the stability and safety of the hydraulic system.