IMPROVEMENTS IN AND APPER- TAINING TO BAKERS' OVENS, AND IN APPARATUS RELATING THERETO
Year: 1879

page_text: LETTERS PATENT to James Greenhough, of 323, High Holborn, in the County
of Middlesex, Baker, for the Invention of "IMPROVEMENTS IN AND APPER-
TAINING TO BAKERS' OVENS, AND IN APPARATUS RELATING THERETO."
Sealed the 10th October 1879, and dated the 22nd April 1879.
PROVISIONAL SPECIFICATION left by the said James Greenhough at the
Office of the Commissioners of Patents on the 22nd April 1879.
"
JAMES GREENHOUGH, of 323, High Holborn, in the County of Middlesex, Baker.
IMPROVEMENTS IN AND APPERTAINING TO BAKERS' OVENS, AND IN APPARATUS
RELATING THERETO."
My first improvement relates to the chaffer or waggon which is used to heat the
oven. Hitherto it has been formed as a plain cast iron bowl with the ashpit below;
I find however that this form causes a large formation of gas and smoke, causing
small explosions. I form three sides of it of grate bars, and the fourth solid as
heretofore. The advantages my chaffer has over the old ones are its lightness, its
weight being under sixty pounds; it will do more work and takes less time over
it; its open sides cause it to make less smoke, and by allowing the heat to spread
it heats the oven more regularly; lastly, slack and cinders may be used without
fear of an explosion.
My second improvement is in the doors and frame. The frame of my experi-
mental oven is four and a half inches deep and fits on the outside of the old frame,
dividing the flue in two; this I find quickens the draft. In new ovens a single
frame cast to suit is sufficient. There is a damper on the top which is opened when
the oven is heating and closed when the bread is in the oven. One advantage of
the damper is if the fire is going too quick by pushing the damper one can regulate
the draft to any degree; another advantage is that there is no blower required
This improvement is very good for cellar bakeries, where there is a shop or house
over the bakery, for by drawing the damper about a minute before opening the
doors all the steam goes up the chimney, and thus the place is kept cooler and more
healthy. This improvement may also be applied to furnace ovens with the same
advantages. There are two large doors and a smaller one between the two to
מ'

page_text: admit the pipe; the opening for the pipe can be varied to suit different pipes. My
third improvement consists in a drawer placed below the door, into which the
contents of the chaffer and sweepings of the oven can be swept. The bottom of
this drawer slopes downward to an open slot or hole in the back, through which
the contents fall into a riddle when the drawer closes. The drawer being closed
the riddle can be rocked or shaken without any of the dust and dirt flying out, and
the larger cinders separated from the others.
My fourth improvement relates to the chaffer pipe. This I make in two or more
lengths, and connect them by pins holding into slots, or other convenient joint,
somewhat after the principle of a screw.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Greenhough in the Great Seal Patent Office on the 17th
October 1879.
JAMES GREENHOUGH, of 323, High Holborn, in the County of Middlesex, Baker.
"IMPROVEMENTS IN AND APPERTAINING TO BAKERS' OVENS, AND IN APPARATUS
RELATING THERETO."
Fig. 1 is a front elevation and Fig. 2 a sectional elevation shewing a baker's oven
fitted with door-frame, doors, and ashbox according to my Invention; Fig. 3 is my
improved chaffer with chaffer box; and Fig. 4 shews a side and end view of the
joint of the chaffer pipe, shewing the pins and the slots into which they fit. In
these like letters refer to like parts. A is the oven; B, the flue; C, the doors;
D, the door frame; E, small door to admit chaffer pipe; F, the hinges; G, damper;
H, ovenstock; I, ash drawer; K, riddle; L, receptacle for refuse ashes; M, chaffer
N, chaffer box, shewing loose shoulders partly raised out of place. My improve-
ments relate to,-
1st. The chaffer or waggon M in which the fuel for heating the oven is placed;
it has hitherto been formed as a plain cast iron bowl with the box below. Owing
however to the want of sufficient air being able to pass to the fire the combustion
is incomplete, and large quantities of gas and smoke are produced, causing small
explosions. Now to obviate this defect I form my chaffer or waggon having three
of its sides of grate bars and the fourth side or back solid as heretofore, as seen M,
Fig. 3, thereby obtaining more complete combustion of the fuel, and consequently
more heat and work from a given quantity of coal with less smoke. The open sides
of the chaffer allow the fire to spread out much more at the top and heat the oven
more regularly; also slack and cinders can be used as fuel without fear of explosions
or insufficient heat, which would have been the case with the old chaffer. The bars
may also be refitted when burnt out.
"
2nd. The doors and framework. The ordinary door and "blower are replaced
by a frame-work D with double doors, as shown at C, Figs. 1 and 2, a damper G
being placed under the flue B to regulate the draught by opening or closing it.
The frame of my experimental oven is four and a half inches deep and fits on the
outside of the old frame, dividing the flue in two; in new ones a single frame cast
to suit is sufficient. The damper G is opened when the oven is heating, and closed
when the bread is in. This part of my Invention, though also applicable to furnace
ovens, is especially valuable in cellar bakeries where thero is a shop or house above,
for by drawing the dampor about a minute before opening the doors the steam
passes up the chimney instead of out into the room, and the place is kept cooler and
more healthy. Hinged to one of the large doors C is a small movable door E,
through which the air pipe leading to the chaffer is admitted. These doors and
framework strengthen the oven fronts, and are easily attached to existing ovens
without moving any bricks in the crown or sides of the oven.
3rd. A drawer I which is placed below the oven stock H, into which the contents
of the chaffer and the dust and refuse from the oven can be swept. Through this
drawer, the bottom of which slopes downwards and inwards, the ashes fall onto a
riddle K, which retains the cinders and pieces of coal. The drawer being closed the
riddle can be rocked or shaken without any of the dust and dirt flying about the
bake-house. The ashes fall into the receptacle L which has a sliding door L', whence
they can be taken away at any convenient time without their dust causing any
damage, as is now the case when the bake house is full of fresh made dough awaiting
to be placed in the oven.
4th. The chaffer pipe, which I construct in two or more lengths, making it much
easier to handle and more convenient for small bake houses. The end of one pipe
is slipped into the other, turned slightly round in one direction, and is fastened by
the pins in the bent slot, see Fig. 4. There is a small handle under the pipe, not

page_text: shewn in the Drawing, which acts as a leg and saves the pipe from rubbing on the
oven bottom. The box N is very light, and by having movable or loose shoulders
may be made or cast to fit any pipe.
Having now described my Invention and the best modes known to me of carrying
it into effect I wish it to be understood that what I believe to be new and desire to
protect under the hereinbefore in part recited Letters Patent is,―
1st. The manufacture of chaffers or waggons for bakers' ovens with sides formed
of bars instead of solid, substantially as described.
2nd. The manufacture of fronts and doors for bakers' ovens, substantially as
described, with a damper G placed below the flue to regulate the draught and air
the oven.
3rd. The manufacture of bakers' ovens with a receptacle in front in which to
place the ashes when removed from the oven combined with a drawer and riddle,
substantially as and for the purposes described.
4th. The manufacture of chaffer pipes in one or more lengths, jointed together,
substantially as described.
In witness whereof, I, the said James Greenhough, have hereunto set my hand
and seal, this Fourteenth day of October, in the year of our Lord One
thousand eight hundred and seventy-nine.
JAMES GREENHOUGH. (L.S.)