VHP INSERTS

Popular coupling standards using British Standard Pipe (BSP) threads, also known as Whitworth threads. The BSPP male will mate with a BSPP female or a female port. The BSPP male has parallel threads and a 30° seat. The BSPP female has parallel threads and a 30° seat. The BSPP female swivel has a tapered nose that seals against the cone seat of the male. The BSPP connector is similar to, but not interchangeable with, the NPSM connector. In most sizes, the thread pitch is different, and the thread angle is 55° instead of the 60° angle used for NPSM threads.

The BSPT (tapered) male will mate with a BSPT (tapered) female or a BSPP (parallel) female port. The BSPT male has tapered threads. When mating with either a BSPT (tapered) female or a BSPP (parallel) female port, the seal is achieved through thread deformation. The use of a thread sealant is recommended. The BSPT connector is similar to, but not interchangeable with, the NPT connector. In most cases, the thread pitch is different, and the thread angle is 55° instead of the 60° angle used for NPT threads.

This is a dryseal thread, the National Pipe Taper Fuel (NPTF) thread. It is used for both male and female ends. This connection is still widely used in fluid power systems, even though it is not recommended by the National Fluid Power Association (NFPA) for hydraulic applications. The NPTF male will mate with NPTF, NPSF, or NPSM females. The NPTF male has tapered threads and a 30° inverted seat. The NPTF female has tapered threads and no seat. The seal is achieved through thread deformation. The NPSM female has straight threads and a 30° inverted seat. The seal is achieved on the 30° seat. The NPTF connector is similar to, but not interchangeable with, the BSPT connector. In most sizes, the thread pitch is different. The thread angle is 60° instead of the 55° angle used for BSPT threads.

The NPSM female has straight threads and a 30° inverted seat. The NPSM thread is used on the female swivel nut of iron pipe swivel adapters. The leak-resistant connection is not achieved through thread sealing, but through the tapered seat at the end of the connector. This type of connection is sometimes used in fluid power systems.

The DIN 24° cone male will mate with any of the three female types listed: female 24° cone with O-Ring, female metric tube fitting, or female universal 24°/60° cone. The male has a 24° seat, straight metric threads, and a recessed counterbore which matches the tube O.D. used with it. The mating female may be a 24° cone with O-Ring (DKO type), a metric tube fitting, or a universal 24° or 60° cone. DIN couplings are available in light and heavy series. Proper identification is made by measuring both the thread size and the tube O.D. The heavy series has a smaller tube O.D. than the light series, but a thicker wall section.

The Society of Automotive Engineers (SAE) specifies that a 37° flare or seat should be used with high-pressure hydraulic tubing. These are commonly known as JIC fittings. The JIC 37° flare male will mate only with a JIC female. The JIC male has straight threads and a 37° flare seat. The JIC female has straight threads and a 37° cone seat. The seal is achieved on the 37° flare seat by establishing a line contact between the male flare and the female cone seat. The threads maintain the connection mechanically.

Type M fittings consist in a Swivel nut end fittings with a 58° male cone nipple sealing.

The seal is achieved when the O-Ring in the male contacts the flat face of the female. These couplings are intended for hydraulic systems where elastomeric seals can be used to prevent leakage and where leak control is critical. This connection provides excellent leakage control. The male connector has a straight thread and a machined flat face. The female connector has a straight thread and a machined flat face. The seal is achieved by compressing the O-Ring against the flat face of the female, similar to a split flange fitting. The threads maintain the connection mechanically.

SAE O-Ring Boss (ORB) threaded fittings are recommended by the NFPA for leakage control in medium- and high-pressure applications. While JIC 37° fittings have the same straight threads, JIC fittings provide a metal-to-metal seal, whereas SAE ORB fittings are sealed by an O-Ring. O-Ring seals provide excellent leakage control because the seal is achieved at the O-Ring rather than at the threads.