slant rumfords
Hey guys, I came across this thread just today and it seems like a good place for discussion.
We are 4th gen masons from CT. and longtime Orton Style Rumford Builders. I've been doing them since 70 when I first read his book.
It's ashamed what's being said about Vrest and the slanted version of the Rumford and when one notes who these people are and their agenda to sell prefab throats etc for the so called "True Rumford", eyebrows should raise.
They privilege themselves to finish writing history by stating, Count Rumford failed in attempt to get his experimental slanted fireplaces to work, therefore he was silent when he promised to elaborate on his findings.
Ben Franklin had long invented the stove that was quickly catching on, while the Count was no doubt encountering many problems trying to adopt this new style into pre-existing,thick front walled fireplaces.
He made mention in his footnote about the only slant he adopted into a bedroom chimney with just a 4'' front wall.
He was used to keeping the back vertically plumb just 4'' behind the face wall which would only be a depth of 8''. He wanted to deepen it to 12 or 14'' for a coal basket or wood logs, so he did so, but only up to 10'' above the fire then straight up again.
This was more like a cove at the lower back that undoubtedly caused mass turbulence the longer it burned, especially a wood fire.
The rhetoric circulating today, suggesting that the Count's potter failed in fabricating a clay throat to suffice his experimental slant firebox, and finally, some 200 years later it's been achieved [for a straight back?]
IF this smoke blowing is fooling anyone it's these young masons, whom only know what they're being told.
Let's remember that Rumford had only partially leaned his wall up to 10'' above the fire in the bedroom f.p. and now was trying to adopt a slant for larger deeper fireplaces on the lower floors because he was amazed with the increased radiant heat.
For him to slant an already deep enough box he'd end up with a deeper box than needed, unless he completely removed the front wall up to about 7 feet or so and perhaps higher on larger f.places, in order to bring the throat forward enough to provide a slanted back wall.
If he ever continued in his experimentation, even after realizing the extra work and cost, he perhaps would've needed Harry Potter to change direction from a forward lean into a backward lean, once he past the throat. I.E.he now has a longer throat that is under the front wall and needs immediate reversal of the chamber in order to clear above fireplaces, and perhaps even side angling as those multi fireplace chimneys were very busy inside with thick stone flues, I know I climbed in them and rebuilt them,.. full of mice droppings and other.
One wouldn't have to stretch his imagination to agree that Count Rumford opted to move on, to compete with Ben in developing his own stove [which he did], after realizing that straight backs were best suited for rebuilding those monstrosities, just as they are better suited for exterior chimneys today, having the throat and chamber at the rear which makes for easy clearance of headers and air spaces.
But there can be no better choice of a firebox than the slant, when the chimney is interior.
This is a point when one must decide on which firebox style works better and where.
This question is often met with rhetorical wizardry on behalf of the marketers, whom make statements like, Slanted Ortons are smoke prone due to turbulence coming from the slanted wall which casts smoke into the room; They can't accommodate a Ti Pi fire therefore smoke that gets emitted from the ends of logs, and is cast forward instead of being high and near the throat, like the "true rumfords"; They don't have rounded breast ;their throats are longer and as much as 1/3 larger in area, resulting in a bigger heat loss up the chimney!; And the straight back has passed epa tests for combustion, suggesting doubt a slant with out the
ti pi fire and it's longer throat will pass.
I will address the epa part first by saying that if the same dry wood is used in a slant or in most any good drawing fireplace, and a large flamed fire is supplied as was in their test, results will be close.
Secondly; To end the rest of the claims I've sent videos to certain people whom were a bit taken aback when they witnessed my 18 year old 50'' slant burning smokeless with the damper at 2-3/4'' the face virtually unstained by eddys.
This killed all the birds with one stone, so to speak, because it shows that no matter what shape the back wall takes, the same throat area for both can suffice a clean draw.
With this being proved, and the slant being the better radiator as even the Count acknowledged, is attest to why for the past 150 years, the slant has been the choice over the straight.
I've only done video visuals of my damper but the next one will show a measured 2''x2-3/4'' inserted into the blade which is fabricated by me.
I like to use my fabricated dampers which I believe enable a thinner throat, although I have adopted cast irons to suffice but not nearly cabable of choking to the same depth.
These fabricated dampers are actually lintel dampers and very handy.Key is proper configuration so when the blade is choked it doesn't cause turbulence.
Lastly to elucidate on Orton's discussing how the slant was time morphed into the smoke prone mess [that these nay-sayers refer to in general and braket together] during the late 50s and 60s.
Raised hearths became popular, and shortened the height of the openings on slants.
This along with starting the slant too high, made the slant's angle too great.
Then came the cast-iron dampers with the big front flanges, with instructions to place them 3 to 6'' above the lintel, and worse many masons put them at the same height thinking the inclined blade would suffice for a smoke collector before the throat. Or an arched opening would flush out with the flange at mid point [the center of the arch]
I can recall giving Orton's book to building inspectors back then so they could enforce proper practice.
This took many years and in fact many architects and inspectors are just now coming around to Orton's descriptions just as the hecklers are too, as they point out some of his add libbed statements such as, "Rumford slanted his fire-backs" and "cold air descends down the back of the chimney as heat rises on the inside then rolls and mixes".
Perhaps they are right in saying air cannot flow bi directional simultaneously within a pipe!
But I say WITHIN A FIREPLACE's chimney, multiple pressure differences constantly occur, resulting in either a full upward flow of heated air coming from inside, this can be from a force full large fire [injection style];or a suction style via good cold outside air movement and ample make up air; A vacuum like scenario, where outside movement is sucking but inside air is not ample to replace [negative].
The latter will cause hot cold turbulence in segments of the chimney all the way up, simulating simultaneous bidirectional currents, and this is what gives impression of constant up down air in a chimney. No matter though, because on sluggish days especially when a low fire is present, a pulsating type draw and eddys will occur if the throat isn't at the front of a shelf and chamber.
I've had this discussion and they claim it makes no difference where the throat is positioned, nor the chamber, BUT THEY ENCOURAGE LARGE TI PI FIRES, bearing out their injection via rounded breast theory and necessity of a ti pi.
It is a longtime observation of mine that slants actually are better suction devices with their longer throats up close behind the face, in contrast to straights being straight up and out the back.
They both draft [suck] on good drafting days but the slant is the better with it's long [true full length] throat and when choked thin it actually increases in strength tremendously actually enebling further choking. This is not as fool proof with slants and unlike the straights, when draft is not so good, a force fire cannot push through as easy, therefore the back wall slope;upper throat / "damper" and chamber need to be right or turbulence will occur.
One very nice equalizer is that when the longer upper body of the slant [including the shelf and chamber] get hot, it's like someone can put a plywood over the chimney and it'll push it off.
I have videos and pics if anyone would like to view them, nothing is for sale it's just for knowledge. In fact the last video was done with a 12'' elm log on a pea soup night which absolutely would devastate most straights with a standard fire......heck who wants to bother stoking and poking a ti pi all night...lol!
Fank Casini Oxford Ct.
http://www.facebook.com/pages/Casini-Masonry/159609824086030
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