<div dir="ltr"><div dir="ltr">Hi Norbert, Alex and Norm;<br><div><br></div><div>It would seem that Richard Hill's furnace does not have a history with furnaces, but it did influence small stoves in a big way. There seems to be a parallel with TLUDs that were first introduced as forced draft stoves, but people needed them as natural draft stoves (notwithstanding the independent discovery of Paal Wendelbo in Norway)</div><div><br></div><div>That old Russian book from 1911 is very interesting. It's good to discover these old nuggets. The physics of downdraft is useful to me, because it helps me to explain the even laminar flow in what I call a 'counter-current' TLUD burner. That burner tries to achieve a high temperature flame on top of the char. There is an old video of it here. <a href="https://www.youtube.com/watch?v=KzYUzJPM3eQ">https://www.youtube.com/watch?v=KzYUzJPM3eQ</a> Simple designs are good, but even this one is too much for Bangladesh where they prefer to use the concentrator ring burner of Paal and Paul Anderson, because it is very easy to make and forgiving to use.</div><div><br></div><div>Cheers,</div><div>Julien.</div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Feb 23, 2024 at 11:13 PM Julien Winter <<a href="mailto:winter.julien@gmail.com">winter.julien@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi Folks;<div><br></div><div>It is good to hear that Dick Hill had so many friends. I am not surprised, because I dug up a little history on him. He died in 2016 at the age of 97. The Bangalore News published a short biography. I have attached it. He was quite a dynamo. His generation was the same as my dad, and they lived through some big World events. My generation has had a relatively quiet time. Not so for the younger generations that will spend their working lives in the upcoming decades. </div><div><br></div><div>Cheers</div><div>Julien</div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Feb 23, 2024 at 8:18 PM Julien Winter <<a href="mailto:winter.julien@gmail.com" target="_blank">winter.julien@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr">Hi Folk;<div><br></div><div>Richard Hill patented his stove in 1981. Vertical Feed Stick Wood Fuel Burning Furnace System. US Patent 4,473,351. The patent was assigned to the University of Maine.</div><div><a href="https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/4473351" target="_blank">https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/4473351</a><br></div><div><br></div><div>Besides referencing a 1944 patent using a vertical stack of wood fuel, there is no reference in Hill's patent to any prior art that burned stick wood only at the bottom.</div><div><br></div><div>There were attempts to commercialize the stove, and they are described in this Wikipedia article:</div><div><a href="https://en.wikipedia.org/wiki/Jetstream_furnace" target="_blank">https://en.wikipedia.org/wiki/Jetstream_furnace</a><br></div><div><br></div><div>The first company went bankrupt because they over-spent their financial capital on North American promotion. Howerever, the stove didn't seem to succeed in the long run. I suspect that was because of their inclusion of a water heating system and dependence on electricity made the stove too complicated for the market. Oil-fired furnaces were easier to use.</div><div><br></div><div>If they had a natural draft, hot air furnace, history shows that they would have succeeded. That was what got me and our neighbors excited about the Harrowsmith article (in the previous email). In the 1970s, there were still a number of historic farmhouses that heated using a wood fueled convection furnace. They looked like a huge octopus in the basement. We had a regular schedule of taking down the flue to clean out the creosote. All the same, the occasional house was lost to a chimney fire. We were swimming in wood fuel, and every spring we had to clear the farm fields of dead-falls. We were always worried that our 150-yr-old farmhouse would burn down.</div><div><br></div><div>Richard Hill's contribution to biomass combustion seems to have been forgotten. </div><div><br></div><div>Cheers,</div><div>Julien</div><div><br></div></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Feb 21, 2024 at 10:15 PM Julien Winter <<a href="mailto:winter.julien@gmail.com" target="_blank">winter.julien@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi folks;<div><br></div><div>When I got involved with TLUD stoves back in 2012, I also saw rocket stoves, I knew I was looking at something familiar. This has been bugging me ever since, and I had to go back to see if my memory was right. </div><div><br></div><div>Through the 1970s and 1980s, my family had a cow collection in Eastern Ontario, Canada. We used to subscribe to a country living magazine called "Harrowsmith." Every month, we would read the magazine from cover to cover. One issue in 1980 described a new stove that was developed at the University of Maine in the 1970s, and commercialized in Prince Edward Island, Canada. </div><div><br></div><div><div>Mariner, R. 1980. "Superfurnace: It Walks, It Talks, It Crawls on Its Belly Like a Reptile …" Harrowsmith, number 27, volume 7, April 1980 <br></div><div><br></div><div>What a name for an article! I have attached a copy. I discovered that there are devoted fans of Harrowsmith that have kept all their old copies, and they have a Facebook page. If you have a vague recollection of an article, they will start sleuthing for it, then post photos of the pages on Facebook. That was a lot more efficient for me than driving to Trent University to look through microfiche film. </div><div><br></div><div>Back in 1980, I wanted to build one of these stoves, but I ended up going to graduate school.<br></div><div><br></div><div>The stove was based on the research that is reported here, </div><div>Hill, RC 1979 Design, Construction and Performance of Stick-Wood Fired Furnace for Residential and Small Commercial Application US Department of Energy, EC 77-S-02-45. 30 p.<br></div><div><br></div><div>Hill's stove was a forced draft stove, but in principle, he had designed what we now call a rocket stove. It has primary air burning char and pyrolyzing wood, with gases burning up stream. The wood is preheated and dried before it starts to burn. The article says that you can virtually burn green wood.</div><div><br></div><div>You can find a copy of Hill's bulletin on-line, and I think Bioenergy Lists has a copy.</div><div><br></div><div>Cheers,</div><div>Julien.</div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">Julien Winter<br>Cobourg, ON, CANADA<br></div></div></div></div></div></div></div></div>
</blockquote></div><br clear="all"><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">Julien Winter<br>Cobourg, ON, CANADA<br></div></div></div></div></div></div>
</blockquote></div><br clear="all"><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">Julien Winter<br>Cobourg, ON, CANADA<br></div></div></div></div></div></div>
</blockquote></div><br clear="all"><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">Julien Winter<br>Cobourg, ON, CANADA<br></div></div></div></div></div></div></div>