BSPP thread and NPT

[cmn8226]

Hello guys,

I am buying a compressor from the UK and bringing it down to the US for some work.

The compressor comes with several thermowells for the temperature switches, but I have to substitute them with Temp Transmitters. I have to buy the RTD's for the transmitters.

The thread on the thermowell is 1/2" BSPP, where it bolts into the compressor housing. Is this compatible with 1/2" NPT? the pressures we are talking about is around 500psi on the thermowell.

 

[DRWeig]

Not compatible at all.

BSPP is not tapered, NPT is -- in addition to slight differences in thread forms and pitch.

You can make an adapter perhaps, or find a 1/2" NPT to 1/2" BSPP adapter -- just might need to make your probe a bit longer to get to the bottom of the thermowell.

OR, find a 1/2" BSPP sensor...

Let's see if anyone else knows a good and quick solution.

Good on ya,

Goober Dave

 

[ash9144]

Not compatible at all (nor is DIN compatible with ANSI, just in case you get to that one next).
There are groups which sell BSP/NPT adapters, which is probably your best bet. Then you instruments stay standard and your odd ball fittings can just stay on the compressor.

 

[btrueblood]

What kind of RTD's are you thinking of using? I'd use a 1/4" o.d. RTD, and slide it thru a compression fitting 1/4" o.d. x 1/2" BSPP. Have to drill thru the fitting first to create a clear bore at 1/4" + some wiggle room...

 

[stanier]

The thread angle & number of threads per inch are different.

Why not buy the correct thermowells with the RTDs?