IMPROVEMENTS IN AIR HEATING AND COOKING APPARATUS
Year: 1879

page_text: LETTERS PATENT to Herbert John Haddan, of the Firm of Herbert and
Company, Solicitors of Patents, of 67, Strand, in the City of Westminster,
Civil Engineer, for the Invention of "IMPROVEMENTS IN AIR HEATING AND
COOKING APPARATUS." A communication from abroad by Wilhelm Pickhardt,
of the City and State of New York, United States of America.
COMPLETE SPECIFICATION filed by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 7th March 1879.
HERBERT JOHN HADDAN, of, the Firm of Herbert and Company, Solicitors of
Patents, of 67, Strand, in the City of Westminster, Civil Engineer. " IMPROVE-
MENTS IN AIR HEATING AND COOKING APPARATUS." A communication from
abroad by Wilhelm Pickhardt, of the City and State of New York, United States
of America.
This Invention consists in the combination in an air heater of a steam generator,
an air heating chamber, a hot air collecting chamber, situated outside of the heating
chamber, a steam coil (one or more) situated in the heating chamber, an air supply
pipe which leads into the heating chamber, an air escape pipe which extends from
the heating chamber into the top or upper part of the collecting chamber, and a
series of hot air distributing pipes extending from the lower part of the collecting
chamber, so that fresh air when admitted to the heating chamber is heated by
contact with the steam coil or coils, and the hot air passing off from said heating
chamber is carried to the collecting chamber, whence it is conducted through
suitable pipes to the different compartments or rooms to be heated. In order to
secure a good circulation of the air the steam coil in the heating chamber is
surrounded by a cylinder which is open at the top. The steam which escapes from
the steam coil is conducted into or through a tank filled with water so as to heat
this water. In order to moisten the air in the heating chamber a jet of moist
steam is injected therein. The bottom of the heating chamber is inclined so as to
conduct the heated air to the escape pipe. In order to heat the air to the degree
required for cooking, frying, and baking, the steam which is used to heat the air
in the heating chamber is superheated before it is passed through the coils in said
heating chamber, and air escape pipe leading from this chamber is exposed to the
action of a direct fire. The air after having thus become highly heated is
conducted from the collecting chamber into suitable ovens containing the articles
Price fid 1

page_text: to be cooked, fried, or baked; after it has acted upon the articles, it is conducted
beneath the grate of the steam boiler. The pipes extending from the collecting
chamber are provided with branches, so that the heated air can be conducted either
into the ovens or into the appartments or rooms to be heated, and the steam pipe is
also provided with a branch, so that the steam can be used either wet or super-
heated. This Invention is illustrated in the accompanying Drawing, in which
Figure 1 represents a vertical longitudinal section. Figure 2 is a horizontal
section. Similar letters indicate corresponding parts. In this Drawing the letter
A designates a steam generator, the steam space of which connects by a pipe a
with the steam coil B. In the example shown in the Drawing the steam coil is
situated in a cylinder C of sheet metal or other suitable material, which is open at
the top and connects at the bottom with the air supply pipe D. Said cylinder is
situated in a chamber E, which is constructed of brickwork or other suitable
material, and from the bottom of which extends the air conducting pipe F, leading
into the air collecting chamber G, at or near its top. This chamber is provided in
its sides near its bottom with a series of distributing pipes H. All those pipes are
provided with suitable stop valves to control the circulation of the air. The escape
opening of the steam coil B connects by a pipe I with a steam coil J, situated in a
water tank K. From the steam pipe a extends a small pipe into the upper part
of the cylinder C, so that when ever it may appear desirable, the hot air in this
cylinder can be supplied with moisture. The surplus heat can be let off from the
collecting chamber into the chimney or any other duct through a pipe H. If
steam is passed through the coil B, the air in the cylinder C becomes immediately
heated by contact with the steam coil and rarefied, so that it rises up. By these
means a current of air is created through the air supply pipe D into the cylinder
C, and as this air becomes heated and rarefied, it rises to the ceiling of the chamber
E, whence it is forced down through the annular space between the cylinder C and
the chamber E into the hot air conducting pipe F, and through this pipe into the
collecting chamber G, which it reaches in a highly heated state, so that it can be
used to beat or warm different rooms or compartments in a building by distributing
it through the pipes H. In order to facilitate the passage of the hot air to the air
conducting pipe F, the bottom of the air heating chamber is made inclined as
shown in Fig. 1. The fresh air which is supplied through the pipe D, and heated
in the chamber E, is driven downwards for the purpose of obtaining a uniform
draught or current of heated air in the several distributing pipes. If desired the
cylinder C in the air heating chamber E can be omitted, and the coil B placed
directly into said chamber. The cylinder C however assists in producing a uniform
circulation of the air. The waste steam which escapes from the steam coil B is
utilized for heating the water in the tank K, either by circulating it through the
coil J in said tank, or by passing such waste steam directly into the water in the
tank. In order to heat the air in my apparatus to the degree requisite for cooking,
frying, or baking, a second steam pipe a extends from the steam space of the steam
generator A, which after having passed through the fire chamber of said generator
connects with the steam pipe a, so that the coil B can be supplied with superheated
steam, whereby the temperature of the air in the chamber E is raised. If super-
heated steam is to be used, the stop valve m of the steam pipe a and also the stop
valve of the pipe fare closed. For the purpose of still further increasing the
temperature of the air, the conducting pipe F is passed through a furnace L, where
the same is exposed to the direct action of the fire, and the effect of this fire can be
increased by enlarging that portion of the pipe F which is situated in the interior
of the furnace L, as shown in the Drawing. In the example shown in the Drawing,
the ovens O for cooking, frying, or baking are situated beneath the collecting
chamber G, and the distributing pipes H are provided with branches H*, which
extend into the upper parts of said ovens. Each of these ovens is furnished with
an escape pipe P, and all these escape pipes connect with a flue Q, which serves to
conduct the heated air escaping from the ovens beneath the grate of the steam
generator, so as to utilize the heat contained in this air for heating the water in

page_text: the generator.
One end of the flue Qmay however be made to open into the
sewer or the chimney, so that if the air escaping from the ovens be too moist to be
conducted beneath the grate of the generator, it can be passed off through the
sewer or chimney. The ovens 0 instead of being placed beneath the collecting
chamber may be erected in any convenient position. The distributing pipes H,
their branch pipes H*, and the escape pipe P of the several ovens are provided
with suitable valves for controlling the direction of the air currents. The pipe F
is also provided with suitable valves for controlling the passage of air to the
collecting chamber. The temperature of the air can be observed by suitably
arranged therinometers. The particular advantages of this air heating apparatus
are, that the heated air passing from the same into the various rooms or compart-
ments is as pure and moist as the atmospheric air; that this air is not contaminated
by smoke, dust, or ashes; that a uniform temperature is produced in all the rooms
or compartments; that the temperature of the air can be readily raised to the
degree requisite for cooking, frying, and baking, and that the operation of the
apparatus requires a comparatively small quantity of fuel. Claims -1. The
combination in an air heater of a steam generator, an air heating chamber, a
collecting chamber situated outside of the heating chamber, a steam coil (one or
more) situated in the heating chamber, an air supply pipe communicating with
this chainber, a hot air conducting pipe leading from the heating chamber into the
upper part of the collecting chamber, and a series of distributing pipes which
extend from the lower portion of the collecting chamber, substantially as and for
the purpose set forth. 2. The combination in a air heater of a steam coil, a
cylinder of sheet metal or other suitable material which is open at the top and
encloses the steam coil, an air supply pipe leading into the lower part of said
cylinder, a close chamber which encloses the cylinder and the steam coil, and a hot
air conducting pipe which extends from the lower part of said chamber, sub-
stantially as shown and described. 3. The combination with an air heating
chamber and with a steam coil situated in this chamber of a water tank or boiler,
and which connects with the discharging end of the steam coil in the air heating
chamber, substantially as and for the purposes described. 4. The combination with
the air heating chamber E, air supply pipe D, and steam coil B, of a steam pipe f,
for moistening the heated air in the chamber E, substantially as set forth. 5. The
combination with the air heating chamber E, air supply pipe D, steam coil B,
cylinder C, and air conducting pipe F of an inclined bottom in the air heating
chamber F, substantially as and for the purpose set forth. 6. The combination
with the steam pipe a', steam coil B, air supply pipe D, heating chamber E, hot air
conducting pipe F, and collecting chamber G, of means for superheating the steam,
substantially as and for the purpose set forth. 7. The combination with the
heating chamber E, hot air conducting pipe F, and collecting chamber G, of a
furnace L for raising the temperature of the air in the conducting pipe, substantially
as set forth. 8. The combination with the heating chamber E, hot air conducting
pipe F, collecting chamber G, and apparatus for superheating the steam used for
heating the air in the heating chamber, of one or more ovens O, substantially as
and for the purpose set forth. 9. The combination with the air escape pipes P,
emanating from the ovens O, of a flue Q, leading beneath the grate of the steam
generator, substantially as and for the purpose set forth.
In witness whereof, I, the said Herbert John Haddan, have hereunto set my
hand and seal this Fourth day of March. A.D. 1879.