Sprinkler Bulb Manufacturing

[Hilary Schmidt]

I was wondering if anyone knew how sprinkler bulbs are manufactured. The melting point of glass is much higher than the boiling point of the glycerin-based fluid inside the bulb. I haven't found anything on the internet about it. Any help would be greatly appreciated!

 

[Compositepro]

The bulbs are not completely full of liquid when initially filled. They are a bulb with a smaller diameter capillary tube attached. They are filled and then the capillary, which is dry and not near the liquid is fused closed.

https://patents.google.com/patent/US5967238

 

[Hilary Schmidt]

Ok, thank you for the help!