NPTF NPSF螺纹检验解释

This section lists the origin and coupling style found in each country. Brief descriptions and dimensional data follows each coupling style.

Iron Pipe Thread Abbreviations N P T National Pipe Tapered Thread F S M Fuels Straight Thread Mechanical Joint NPTF This is a dryseal thread; the National pipe tapered thread for fuels. This is used for both male and female ends. The NPTF male will mate with the NPTF, NPSF, or NPSM female. The NPTF male has tapered threads and a 30° inverted seat. The NPTF female has tapered threads and no seat. The seal tales place by deformation of the threads. The NPSM female has straight threads and a 30° inverted seat. The seal takes place on the 30° seat. The NPTF connector is similar to, but not interchangeable with, the BSPT connector. The thread pitch is different in most sizes. Also, the thread angle is 60° instead of the 55° angle found on BSPT threads. NPSF The National pipe straight thread for fuels. This is sometimes used for female ends and properly mates with the NPTF male end. However, the SAE recommends the NPTF thread in preference to the NPSF for female ends. NPSM National pipe straight thread for mechanical joint. This is used on the female swivel nut of iron pipe swivel adapters. The leak-resistant joint is not made by the sealing fit of threads, but by a tapered seat in the coupling end. NPT Pipe Thread Dash Size Nominal Size in. -2 -4 -6 -8 -12 -16 -20 -24 -32 1/8 1/4 3/8 1/2 3/4 1 1 1/4 1 1/2 2 No. Threads per Inch 27 18 18 14 14 11 1/2 11 1/2 11 1/2 11 1/2 Female Thread Thread I.D. in. 23/64 15/32 19/32 3/4 61/64 1 13/64 1 17/32 1 25/32 2 1/4 Male Thread Thread O.D. in. 13/32 35/64 43/64 27/32 1 1/16 1 5/16 1 43/64 1 29/32 2 3/8 NPSF(燃料管用耐密平行螺纹) NPSF属于干密封燃油直管内螺纹，它没有外螺纹，主要用于软材料,可配合外螺纹NPTF(干封闭)使用。

以下为较常用之美制平行管螺纹用丝攻（NPSF）的规格。

NPSF1/16-27 NPSF1/8-27 NPSF1/4-18 NPSF3/8-18 NPSF1/2-14 NPSF3/4-14 NPSF1-11½

美制螺纹它们的开头代号大多以N或是U两种为主，U开头的有UNC粗螺纹、UNF细螺纹、UNEF特细螺纹此外还有（UNS,UN)等，以N开头的为管用螺纹有（NPT,NPTF,NPTR,NPTH,NPSC,NPSF,NPSM,NPSL,NGT)等。对于在使用美制螺纹时，有什么问题可致电于我司。

以下为较常用之美制管用螺纹（含平行管螺纹及圆锥管螺纹）。 1.NPT(美制管用推拔螺纹)

在ANSI(美国国家标准)规格中,称为美国标准管用推拔螺纹,属一般用途锥管螺纹。

有外螺纹与内螺纹.NPT外螺纹不可以对NPT内螺纹配合,有时也可配合NPSC,这点类似于PT(R)。

2.NPTF(美制管用耐密推拔螺纹) NPTF属干密封锥管螺纹，它的外螺纹有着PT、NPT一样的功能，有时也配合NPSF、NPSI(都是内螺纹)，因为这种螺纹都是峰尖、根浅。 3.NPSC(美制直管接头用管用平行螺纹)

NPSC属于美制管接头直管内螺纹，它和PS（RP）一样，只有内螺纹,它可以用于连接NPT外螺纹。

4.NPSF(燃料管用耐密平行螺纹)

NPSF属于干密封燃油直管内螺纹，它没有外螺纹，主要用于软材料,可配合外螺纹NPTF(干封闭)使用。

5.NPSM(机械连接用直管螺纹)

NPSM有内、外螺纹。可在设备上自由配合。属于机械连接用直管螺纹，具有比较精密配合外螺纹、内螺纹两方都是平行的组合螺纹。它的精度略近于PF(G)的A级,有0.03 以上的间隙,用于无内压作用的管道连接。 6.NPSL（机械接合用平行螺纹）

NPSL属于机械接合用美国标准管用平行螺纹，与锁紧螺帽作松配合的机械接合螺纹。