Improvements in the Construction of Bakers Ovens.
Year: 1896

page_text: Improvements in the Construction of Bakers Ovens.
JOHN MELVIN Engineer Saint Rollox Iron Works Glasgow in the County of
Lanarkshire, Scotland do hereby declare the nature of this invention to be as
follows:-
This invention consists in improvements in the construction of baker's ovens
heated by steam pipes on the "Perkins" system and is designed to effect a more
complete control over the distribution of heat & also to effect a greater economy
in fuel.
According to my invention the oven is constructed as follows:-The furnace is
placed outside of the baking chamber either at the back or side & two horizontal
rows of steam pipes, one upper & one lower, pass from the furnace into the baking
chamber. The lower row is placed under the floor of baking chamber forming at
the furnace end, the fire bars on which the fire rests.
The upper row is placed below roof of baking chamber passing into the furnace
above the level of the fire. The crown of furnace communicates to a main vent
or chimney controlled by a damper. Between the back wall of baking chamber
& furnace a flue is formed extending preferably the whole width of furnace
through which flue both rows of pipes pass, said flue communicating with ash pit
at bottom and passing upwards through a damper into the main chimney at a point
above the damper which communicates to the furnace.
The furnace and ash pit are each provided with the usual doors, in addition to
which seperate doors dampers or other equivalents are provided to admit cold air
into each.
This system of flues is designed to regulate the temperature within the baking
chamber so as to give greater heat at the top & less at the bottom, or otherwise
less at the top & more at the bottom.
This is effected as follows:-By closing damper in connection with flue behind
furnace; opening damper at crown of furnace; & admitting cold air to ash pit,
the bottom pipes on which fire rests will become partially cooled while the hot air
will rise & heat to a greater temperature the top pipes within the furnace, thereby
giving greater top heat within baking chamber.
Or by opening damper connected with back flue, closing damper at crown of
furnace, closing admission of air to ash pit & opening same into furnace, the
draught will then pass downwards through the fire & bottom pipes, then to the
back flue heating the bottom pipes a second time, passing upwards through the top
pipes heating them in less degree, thereby giving greater bottom heat within the
baking chamber.
The heat in this way is utilized to the greatest advantage, economizing fuel and
at the same time giving perfect control over the temperature within the baking
chamber.
JOHN MELVIN.

page_text: JOHN MELVIN, Engineer, Saint Rollox Iron Works, Charles Street, Glasgow
Scotland do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention consists in improvements in the construction of baker's ovens
heated by steam pipes on the well known Perkin's system effecting greater control
over the top and bottom heats within the baking chamber, whereby these can be
increased or diminished at will, while at the same time greater economy of fuel is
effected.
Fig. 1 is a longitudinal section through line C. D. ou plan.
Fig. 2 is sectional plan of baking chamber & furnace."
Fig. 3 is elevation of back wall showing furnace doors and dampers.
Fig. 4 is transverse section of furnace through line E. F. on plan.
The reference numbers is the different figs. denote the same parts.
The baking chamber 1 is constructed in the usual way with sole 2 on which the
goods are baked. 3 being the oven door and 4 the usual steam flue with swing
damper 5.
Chamber 1 is heated by a top row of steam pipes 6 and bottom row 7, the
former giving the necessary top heat and the latter the bottom heat. Both rows
extend into the furnace 8 where the bottom row acts as furnace bars for the fuel
to rest on. Each pipe is partially filled with water and hermetically sealed in the
usual way.
The furnace is provided with doors 9, ashpit 10 and ashpit doors 11.
Between the baking chamber and furnace a flue 12 is formed extending preferably
the full width of furnace, communicating with ash pit 10 at bottom, and chimney 14
at top, having damper 13: both rows of pipes pass across this flue.
The crown of furnace 8 communicates direct by flue 15 and damper 16 with
chimney 18. Chimney flues 14 and 18 can join into one at a higher level than
shewn on drawings.
By means of the flues & dampers described the furnace heat can be directed on
to the top or bottom rows of pipes equally or unequally. Thus if greater top and
less bottom heat is desired within the baking chamber, the furnace heat is passed
through the top rows of pipes 6 only, by closing damper 13 and opening damper 16,
closing furnace door 9 and opening ash pit door 11. Otherwise if less top and
greater bottom heat is required, the furnace heat is carried by down draught
through the fire and bottom pipes 7 into ashpit 10, thence by flue 12 to chimney 14,
heating thereby the bottom pipes 7 a second time, while the top pipes 6 are only
heated once. This is effected by opening damper 13 and closing damper 16,
opening furnace doors 9, and closing ash-pit doors 11.
An equal top & bottom heat is obtained by partially opening dampers 13 and 16,
while doors 9 are partially opened, and 11 closed.
Hitherto ovens heated by steam pipes on the Perkin's system have had their
flues constructed in such a way that the furnace heat goes direct into the chimney
after having passed through between the pipes only once, whereas according to my
invention, by means of flue 12 the heat passed through the pipes several times.
This increased utilization of heat effects a considerable saving in fuel, besides
yielding the advantages already described.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
1st. The construction of baker's ovens heated by Perkin's steam pipes having a
vertical flue between the furnace and baking chamber for the purpose described.
2nd. The carrying of the steam pipes across a vertical flue placed between the
furnace and baking chamber, within which flue said pipes are heated a second time
by the products of combustion coming direct from the furnace, for the purpose
described.
3rd. The combination of furnace 8, ash pit 10, and vertical flue 12 for the
purpose described.
1007
JOHN MELVIN.