Good job finding those patents! :ThumbUp:
I tried searching for a patents for Grabler and could not find anything to support my theory. I've been in a lot of basements and boilers rooms of the old houses and buildings around town over the years. Always have my nose in the air looking around at all the mechanicals trying to figure out what makes the place tick. Heating and cooling is another interest of mine especially the old hot water and steam systems of yesteryear. Maybe I saw those clamps in use someplace in the past. :dunno:
It is sad how the fit and finish of the old things were so heavy duty compared to now. One thing I suppose was rust and corrosion of the old stuff was a larger concern compared to the alloys now but still. My grandparents had an old originally coal fired gravity furnace that had been retro fitted to a NG burner. Power would go out and the rest of us were cold we would go to my grandparents and even with the natural gas burner update it would still be keeping the house toasty thanks to a standing pilot and the high tech of the time period thermocouple that generated it's own electric to operate the gas valve. No it was far from efficient. Probably been lucky to get more then 30-40% from it even with the flame baffles on the new gas burner that directed the flame toward the old cast iron walls of the fire box. But the thing was bolted and riveted together like an army tank with the manufacture name, city, and state proudly cast into the loading and ash doors, (now we get a sticky label) sheet steel wrapped around that to form an air cavity to feed the massive 12"+ pipes up into the house with neatly wrapped insulation (probably asbestos) around each pipe. You could melt your shoe soles and darn near set your socks on fire standing in front of the wall vents upstairs on the coldest winter day. One of those fond memories of the past I think about while standing in front of the vent from my heatpump / electric furnace with the 90°F air sifting out.
