The Siren Board

For those who ever wanted to see what the Model 120 looks like taken apart, well here is your chance. You can see the Teflon coated stator walls and Teflon coated rotor. This was a unique design and feature of the 120 as to not allow for air to leak around the rotor when the ports close, and as well as for no salty costal air and moisture to get inside in between the rotor and stator and rust the rotor stuck. The tolerance is super tight and definitely the tightest I’ve ever seen and no mass produced sirens atleast in the US have a tolerance this tight and or even machined as well. This definitely has a much better machining job then my Thunderbolt, Model 2, and even Model L, basically any siren like that in general, the 120 has a very well done build quality, as it was built to perform and not to sell and market like mass produced sirens.

You can clearly see there is no vanes on the rotor, and all that is inside the stator and base assembly is the air diffuser veins which evenly distribute and direct the air from the blower to each port of the stator. There is no rotating vanes on the rotor meaning it solely requires air from the blower to be loud, but due to the extremely tight tolerances, without a blower and with the bottom intake covered, the siren can still actually chop ambient air that is trapped in the diffuser, and as low as 20 rpms or so you can hear the rotor actually chop the air which is very impressive for a siren with no veins to create a vacuum and suck in the air to be chopped like your standard mechanical siren, but since this is a pneumatic siren and doesn’t use the stator ports to chop the air, the rotor chops the air primarily from the blower, and then the sound exits the stator and out the horns.

Also have a video on YouTube as well: https://youtu.be/yOcVk3SrqtY

very cool! the tolerances on that are insane, to say the least. I wish the design would have been developed more, I feel like coastal locations could really benefit from a corrosion resistant design. one of the main reasons that tillamook county cited for removing their sirens was rust and corrosion driving maintenance costs higher, and seeing as though one of the model 2s basically completely rusted away prior to removal, something built for the environment would definitely last longer.

looking forward to when this is fully assembled and running!

Neat siren! I find it hard to believe that a power utility decided it would be cheaper to design and have custom sirens made instead of getting something off the shelf that would meet their requirements better. But I guess it worked!

Was the blower mounted at the bottom of the pole or up near the siren? It's hard for me to tell from the pictures I've seen.