Constructed from a 9kg LPG cylinder, the bubbler/flame trap is fitted with water heating element and thermostat. The plan includes a simple bubble diffuser plus a window to monitor level and activity.
1Aug2013. I reviewed the plan, fabricating a "draw back arrestor" from a small LPG (yellow)cylinder. This will ensure the bubbler water is not drawn back toward the retort when it cools.
22Aug2013 To explain the draw back arrestor in more detail, the incoming vapors enter at the top of the yellow vessel, through the cylinder and connecting pipe which extends to an inch from the bottom of the red vessel. The red bubbler vessel is half filled with water so acts as a type of safety valve and a handy flow indicator. (My next step is to put a sight glass to be able to see the bubbles) The reason the yellow draw back arrestor is there is to prevent water being drawn back upstream when the retort cools and contracts at shutdown of the process. Effectively, the volume of water that is above the lower end of the bubbler pipe is less than the total volume of the yellow vessel. Therefore the yellow vessel can never fill up and overflow.
23Aug2013 To prevent tipping over, the bubbler base is mounted using 1/4" screws to the shelf.
7Sept2013 A flash back arrestor is fitted between bubbler and servo valve. It's recycled from an earlier prototype. It has swarf inside. In at top, out at bottom.
10Sept2013 The viewing ports for the bubbler are ready. Pics show construction and assembled. There's one on each side so hopefully I can "see through". Maybe a light source will be needed to aid viewing. The lenses are from polycarbonate which may cloud up with use. Cork is used for the seal.