I've had trouble with a lot of smoke tube & box gizmos in conventional gas grills too. What I've found works as good as anything is buying round stainless mesh strainers meant for kitchen sinks. $1 at walmart, about 3" round at the bottom, about 6" dia at top. Fill will pellets (not chips) and start by placing direct on the gas burner for a couple minutes. Once you have a flame, pick up with meat tongs, blow out, and place them on a grill under your meat. (sometimes you have to repeat the ignition phase.) 3 or 4 of these in a medium gas grill gives you pretty good smoke. For longer cooks, you can top off with fresh pellets once they've burned half way. Once in a while, one will flame up when I open the lid, but I keep an aluminum pie plate handy to then cover them up. Remove it when closing the lid and everything stays under control.
If your smoke tube only flames up when opening the lid, having an old bread pan or some sort of metal shroud ready to toss over it may take care of the issue. You don't have to choke off all air, just break up that big upward draft.
I had as many problems with tubes burning out as flaming up so I pursued other approaches. It's for this reason that so many with electric smokers end up putting their smoke-makers in their own separate box (e.g. search on "mailbox mod") so the air flow to/through them stays more constant.