I used to wrap the vacuum cleaner tube with duct tape to get an airtight fit, then wrestle with it a bit to switch from flare (no filter) mode to run mode with filter. Here’s a better and quicker connect/disconnect method. This is just a method, your sizes may vary. A flaring method will be incorporated into the final engine feed design.
Dig out a matched pair of those old vac wand pieces.
Cut a 3" piece off the receiving end (piece on left).
Epoxy the vac piece inside the 1 1/4" thin wall pvc pipe.
Glue the 1 1/2" coupling to the 1 1/2" stub on the exit side of the filter shutoff. Glue in the 1 1’2" x 1 1/4" reducing bushing and lastly glue in the 1 1/4" pvc pipe containing the vac piece.
Flare connection and shutoff. Fits like a glove, quick and easy and air tight. This valve didn’t need the 1 1/2" coupler.
Flare setup. Shut filter valve, open flare valve to direct gas to the swirl burner. I installed the “Y” upside down.
. When you are satisfied with the flare, switch to the run set up. ALWAYS shut off the vacuum first, then the flare valve. This will eliminate the point of ignition from the swirl burner. Pull hose from swirl burner and lay on ground. Quickly switch the hose from the flare outlet to the filter outlet and immediately open the filter valve and turn on the vacuum. MOST IMPORTANT: let the gas run for several minutes +/- to flush the oxygen from the filter unit and lines. Caution here, if in doubt let the gas go longer before using it. The filter could be a bomb.
Move vacuum closer so you can shut it off from the pallet. Do this first. Then shut off the flare valve, step down disconnect the swirl burner tube (notice the old duct tape sealing method) and step back up move vacuum line to filter and open the filter valve. If it takes you 10 secs, you’re too slow. Reconnect hose to swirl burner ( turn on fan) or engine, continue burn. If connecting to an engine you bypass the vacuum (it’s now provided by the engine).
The weather is supposed to be nice tomorrow, so I’m going to burn some measured amounts of wood, take some data and video and report back. My friend and neighbor, Bill, is coming over to watch the firing, it should be fun.