Gasifiers spitting back

The full story is in another thread, but it bears repeating here.

Assume that gasifiers can spit back at any time, but the risk is highest at the end of a run, when there’s plenty of volume for gas mixtures to build up, and plenty of hot stuff to ignite it. Use any combination of a mirror, a pyrex window, and goggles, but don’t look directly down the tuyere.

Well put Brian, and hoping you recover soon. I hear the eye is the fastest healing part of our body. Most times at the end of my runs, I cap it off and walk away, hence no problems there. BUT start up is another story. Just today, after 3 hours of “off” time, I hoped to re-kindle the coals and go again. I decided to open the exhaust and run the exhaust blowers to see if the temps would come up. The inlet valve was sticky so as the temps rose, I proceeded to oil/de-tar the gate valve. After several openings and closings, (luckily my back was turned) It gave a hearty belch and sprayed the back of my light colored shirt with [email protected]&^$%#&! While I’m not sure why this happened, I will use a different method next time and not stand in the back while trying it! You already said it “anytime” So right.

Now, what would a skeptical insurance underwriter make of these two similar incidents in two days? There’s a clear risk of explosive mixtures building up during startup, shutdown, or with air leaks. Low volume, low pressure, low energy explosions, but enough to hurl debris. We need to think about designing out the explosion risk- sealing, venting, purging- and the consequences- give the explosion somewhere safe to go

Hi Brian, Your experience with a belching gasifier is something I also experienced. Fortunately for me, I was not looking in the air inlet when it happened. But I saw the event happen and it shot a shower of sparks ten feet out of the air inlet. After seeing that, I built a screen over a pipe nipple that screw into the air inlet. At the least, it will slow down the velocity of any charcoal embers that may get expelled from the generator.
Here is what I think happened. It was at the end of the run. There was a small air leak in the lid of the charcoal gas generator that allowed a little oxygen to mix with the charcoal gas before leaving the generator. As the charcoal is consumed and drawn down, it allows the heat generated at the oxidation zone to move upward into the generator. At some point, there is insufficient charcoal to insulate this combustible gas from the heat and ignition occurs. The sudden increase in pressure pushes hot charcoal embers out the air inlet. This is not the time to be looking at the glowing coals!!!
Now when I demo my Simple-Fire, I use a mirror to allow others to observe. I have been wearing glasses since I was 6 years old. They have saved my eyes many times, but………. Still have to be careful, Thanks for sharing your near tragedy. The wise will learn from it but the fools will ignore it.

Unfortunately there is an inherent danger in any “power” system. From the 9v battery in your pocket that shorts against your car keys and sets your pants on fire, to 3 mile island. It simply cannot all be prevented. A great part of this forum is to simply make others aware, and learn from these “experiences”.

When this occurs in my systems it is usually at shut down. I think it has to do with pulling the vacuum and then relieving it. So what I think is happening is the more refined gas that is in the grate is being sucked back when when the vacuum is released and mixing with the air in the hearth. So you then get that puff. So what I do now and recommend to all is to cap off the gasser first before performing a full shut down. Try and get as much air out of the system as you can and let the reaction cool so the gas is less potent. When running an engine I cap of the machine and let the engine run until it dies. This will also help get moisture out of the hopper.

I would just like to pass on a deadly issue with batteries, A few days ago a 4 year old girl died not far from where I live. She swallowed a small Lithium Battery the button type found in watches etc.

“Risks inherent in any power system”… Horses are a power system. That’s probably, like, why they, like, talk about “Horsepower”. I was telling the story to a work colleague, who concluded that I had a dangerous hobby, but she went on to recount a list of injuries sustained riding horses. I don’t see risks out of perspective, but the trouble is, we’ve had ambulance chasing lawyers in the UK for a few years now, and everyone’s on edge about new risks.

Our TV channels seem to be flooded with personal injury lawyers at the moment. It is true that whatever “plague of annoyance” America gets, it only takes a few years for it to catch on in Britain and “had an accident that wasn’t your fault” seems to be a popular phrase on both radio and TV. I keep getting texts and calls regarding “that accident I had in which I could be owed up to £4000”. Must have been a good accident as all I have ever suffered was minor whiplash for 24 hours after my car got shoved under a tipper truck by a less than observant car driver behind me.

It is naff that you got injured, but it serves as a learning curve to the rest of us and helps build up a" user manual" of safe gasser operation through some trial and error. This gets me thinking that if a charcoal gasser is vehicle mounted the intake should be positioned so that it cannot accidentally backfire onto anything or anyone. What a thing to have to explain to the cop car behind when you vent hot coals all over his bonnet!