A New or Improved Air and Dust Tight Door for Ovens and the like.
Year: 1893

page_text: Date of Application, 11th Feb., 1893-4ccepted, 22nd Apr., 1893
COMPLETE SPECIFICATION.
A New or Improved Air and Dust Tight Door for Ovens and
the like.
I, JULIUS BAHLSEN of 45 Lessing Strasse, Berlin, Kingdom of Prussia, German
Empire, Merchant, 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 :-
My invention relates to an improved air tight door for the ovens of domestic
stoves, bakers ovens and the like, also applicable for use as a damper or ventilator
in chimneys and other hot air passages, the object of which is, that when in its
closed position it absolutely precludes the escape of heat from the oven to which it
may be fixed, or when used as a damper or ventilator and built in with the domestic
or other chimney, entirely prevents the escape of dust or soot during the cleaning
of said chimney, or by the force of downdraught therein, thereby preventing
deterioration of the contents of the apartment, or contamination of the atmosphere
therein by the escape of carbonaceous gas.
The said door may be of cast iron or other suitable metal hinged to a frame of
similar material, and arranged to form part of, or be attached by suitable means
to, any type of domestic oven, or built in the brickwork of bakers ovens, or the
chimneys of either or both, or other places used for the conveyance of hot air.
The said door is constructed in such a inanner that in horizontal cross section the
half or thereabouts of its length nearest the hinge is, preferably, about twice the
thickness of the remainder, such reduction of thickness being provided upon
the inner surface thereof, and within the recess thus formed is placed a flap or
shutter, hinged to the thicker part of the door, and in the opposite direction
extends slightly beyond the outer edge thereof, said extension fitting into a recess
in the frame when the door is closed, a like vertical recess being formed in the
opposite side of the frame for the reception of a flange or extension formed upon
the inner surface of the hinged end of the door. A ridge or groove is also pro-
vided in the upper and lower surfaces of said frame, and into these and the before
mentioned recesses a packing of asbestos is placed, against the former of which
the upper and lower edges of the door and flap abut when the door is closed, while
the latter receives the extension upon the door and the free vertical edge of the
flap, and by this means a perfect air tight seal is formed when the door is shut and
latched, or otherwise fastened.
In order that my invention may be fully understood I have appended a sheet of
drawings.
Fig. 1 is a front elevation of the said door and frame, the former slightly ajar.
Fig. 2 is a horizontal section of the same.
Fig. 3 is a similar view shewing the manner in which the extension upon the
door and the free end of the flap or shutter engage with the vertical asbestos packed
recesses in the frame, when closed.
Fig. 4 is a vertical section of the said door and frame taken upon the line e f
Fig. 3.
The frame a is fixed or built into the brickwork, or rivetted or otherwise con-
nected to the stove or other oven, by means of the flanges a', and upon the front of
said frame the door bis hinged by means of the lugs. Upon the inner surface
of b, a recess b' is formed, which receives a flap or shutter 6, hinged to the door
at 6, the thickness of and the door at 61 collectively, being the same as the
thicker portion of b, and the width of being slightly in excess of the width of
the recess ¹ extends this much beyond the edge of when shut into the said
recess. Two vertical recesses a and a*, are formed in the frame a, into each of

page_text: which a layer or layers of asbestos packing c is placed as shewn at Figs. 1 and 2, a
like packing of asbestos being placed in grooves a² formed in the upper and lower
faces of a as shewn at Fig. 4.
Fig. 1 represents the door open at the angle shewn by the dotted line d
Fig. 2.
When the door is closed the free end of the flap or shutter is embedded in the
asbestos packing c in the recess a while the extension 6 upon b would enter the
recess a³ and be embedded in the packing therein, as shewn at Fig. 3, at the same
time the upper and lower edges of b and 6 would press firmly and closely against
the asbestos c in the grooves a' in the upper and lower faces of a, as shewn at
Fig. 4, so that a perfectly air and dust tight closure is obtained thereby, and the
door may be kept so closed by the means of a latch and knob the latter
engaging with a catch i upon a, or by any other suitable means.
The door may
be furnished with suitable brass or other ornaments as fancy may direct, and
is admirably suited for bakers ovens as a preventative of the escape of heat
therefrom.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is,
1st. In an improved air and dust proof door for attachment to domestic stove or
other ovens, or the chimneys of these or other air, or other passages, the herein
described combination of parts connected and operating substantially as set forth
and shewn by the accompanying drawings.
2nd. In combination with domestic, bakers or other ovens, or the chimneys or
smoke passages thereof, and rivetted or otherwise connected thereto, or built in the
brickwork thereof, the construction and use of a frame a, provided with recesses
or grooves a³, a³ and a*, containing asbestos packing e, and provided with flanges a'
for attachment to said oven-or brickwork, and having hinged thereto by the means
of lugs, a door b, provided with an extension 6 for engaging with the packed
recess a³ and recessed at 1 for the reception of a flap or shutter 62 hinged thereto
at, and engaging when said door is closed with the packed recess a³, and
collectively with babutting against asbestos packing c in a³, the whole connected
and operating as and for the purposes herein set forth and shewn by the appended
drawings.
Dated this 11th day of February 1893.
GEO. THOS. HYDE,
4, Moorfields, Fore Street, London, E.C., Agent for the Applicant.