Vintage pyrotector duct detector

[Caleb_Culwell (Locks and alarms)]

I found this on eBay

[TheCarson116]

Ooh, nice find! Not sure I’ve ever seen that before! (interesting how it has an integrated key switch too)

[Caleb_Culwell (Locks and alarms)]

Yeah i like the key switch too. I wonder if it is ionization or photoelectric??

[MrFireAlarm]

Most likely Ionization, judging by its age.

[Caleb_Culwell (Locks and alarms)]

Yeah. Thinking about it now its most likely ionization

[Alexis_T (Alexis C. R. Trinquet)]

I’ve never seen a duct detector using a vacuum gas-filled tube (in this case, a Thyratron), that’s a first for me.

Nice find.