BSPP threads - washer / no washer

[Vindicit]

So I have these fittings that are said to be G1/4 threads which are BSPP straight threads. The original female fittings inside have a copper crush washer that bottom out on a flat backing that seal against the male and female connections. I bought new female fittings to replace them that are also BSPP straight threads but they do not have these same copper crush washers and they are not flat inside like a flat washer could have been inside, they bottom out on a taper/cone/angle cut. This new fitting does thread all the way down 10+ threads so the threads are correct.

My question is, is there more than 1 kind of BSPP thread that does not have this crush washer? If yes are the 2 types compatible if threaded all the way down until they bottom out?


thread explaination

https://www.ralstoninst.com/news/story/the-difference-between-npt-bspp-and-bspt-seals

 

[XL83NL]

BSP has 2 thread types, one for straight thread, one of tapered.
The one for straight threads, ISO 228, is used (a.o.) in ISO 1179 joints, where a crush washer (as you call it - I call them an iso parallel ring) is used for sealing the joint.


Huub

 

[Vindicit]

Right so BSPP is straight parallel threads and BSPT are tapered threads. From this coupling that I got they are indeed straight parallel threads which according to the definition will require this ring/washer. So they are not BSPT. Is there 2 different versions of BSPP with one that does not have a washer or ring to do the sealing?

 

[XL83NL]

Im not overly familiar with BSP (either -P or -T), except for ISO 1179, but I always believed that a female taper would go into a male straight joint to create a sealing on the threads. I think we also 'do' straight to straight without using a ring or washer, but Id have to check.

Does the fitting/coupling under consideration comply to a certain standard?

Huub

 

[Vindicit]

The information says ISO 6150/B. But I think thats just the quick disconnect profile.

 

[XL83NL]

ISO 6150 is for quick connectors. Going through the standard, I dont see any reference to a standard for BSP-threads, not any picture of threads.

Huub