IMPROVEMENTS IN CHIMNEY TOPS OR VENTILATORS
Year: 1882

page_text: LETTERS PATENT to Thomas James Baker of Newark in the County of
Nottingham for an Invention of "IMPROVEMENTS IN CHIMNEY TOPS OR
VENTILATORS
"
PROVISIONAL SPECIFICATION left by the said Thomas James Baker at
the Office of the Commissioners of Patents on the 18th July 1882.
THOMAS JAMES BAKER of Newark in the County of Nottingham
MENTS IN CHIMNEY TOPS OR VENTILATORS
"
"
'IMPROVE-
My Invention relating to improvements in Chimney tops or Ventilators has for
its object the more simple and effectual construction of the same for preventing
down or return currents of air or retarded ventilation in chimneys uptakes shafts
or the like
For this purpose I provide the top of the chimney or shaft with a double shield
shaped head having a narrow uniform slit or opening formed or left between the
parallel edges of the said shield shaped plates which extends across the centre of
the chimney or shaft. These narrow slits or openings should be equal to the
effective area of the chimney or shaft to which it is to be applied the said openings
being arranged in curved or angular planes according to the shape or configuration
of the aforesaid plates of the Ventilator
In practice I find circular parabolic or angular tapering shaped metallic plates
buckled or pressed out in their centres to answer the purposes of my Invention but
other modified forms may be employed
In forming or constructing the said chimney tops heads or ventilators I take
two corresponding buckled or shield shaped plates as above described and suitably
fix or attach them to a metallic tube or other convenient chimney or shaft
termination so as to leave the above mentioned narrow opening or space between
or at their edges or peripheries. The edges of such plates may be retained in
proper parallel relation to each other by means of struts or distance pieces
conveniently arranged
"

page_text: In this manner a chimney top or ventilator is constructed of the most simple
character presenting every facility for the rapid and effectual egress of smoke or
noxious gases and at the same time prevents the ingress of any external wind or
air currents from above. For owing to the narrow construction of the said opening
on the top or ventilator and the peculiar sloping construction and relation of the
said buckled or shield shaped plates of which it is formed the wind or air in
whatever direction it may impinge is caused to be divided intercepted and deflected
so as to in noway interfere with the efficiency of the draft or ventilation of the
chimney or shaft
Although I have described the said tops or ventilators as being constructed of
metal it will be readily understood that they might be formed of earthenware or
other suitable materials

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas James Baker in the Great Seal Patent Office on the
18th January 1883.
THOMAS JAMES BAKER of Newark in the County of Nottingham
MENTS IN CHIMNEY TOPS OR VENTILATORS."
"IMPROVE-
My said Invention relates to improvements in Chimney Tops or Ventilators and
has for its object to efficiently prevent down or return currents of air or retarded
ventilation in chimneys uptakes shafts or the like In carrying my said Invention
into effect I provide the top of the chimney or shaft with a tapering, hood or head
having narrow slits or openings formed or left between the edges of the plates
forming the said hood or head which slits or openings give passage across the
centre of the said chimney or shaft In this manner I construct a top or ventilator
of an extremely simple character the angular formations of which serve to
effectually deflect any extraneous impinging currents of air without retarding or
interfering with the proper discharge or egress of the noxious gases.
And in Order that iny said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the corresponding figures.
Figures 1. 2 and 3 of the accompanying drawings represent a side and front
elevation and plan respectively of a chimney top or ventilator constructed and
arranged according to the essential features of my said Invention whilst Figure 4
represents a side elevation of a similar top or ventilator constructed in terra-cotta
or earthenware Figures 5. 6. 7 and 8 represent side elevations and plans of
modified constructions of chimney tops or ventilators in accordance with my
Invention.
Referring to Figures 1. 2 and 3 of the drawings which illustrate the essential
features and principle of my said Invention (the other Figures being simply
modifications or developments of the same) a and b are two corresponding
tapering shield shaped or buckled plates having angular or inclined portions as
at a ba² b² which may be conveniently carried by auxiliary cheeks or pieces C
connected with a bed plate c through which the shaft A passes and is attached
The aforesaid angularly formed tapering buckled plates a and b are suitably
connected or carried by the pieces Č. c in such a manner as to leave or provide
a narrow slit space or opening B between the edges of the said plates and
intersecting the apparatus as more clearly shown in plan in Figure 3 of the
drawings These narrow slits or openings (B) crossing the centre of the
chimney or shaft should have an aggregate area equal to about the effective area
of the chimney or shaft to which it is to be applied the said slits or openings
being in straight curved or angular planes according to the shape or configuration
of the aforesaid head plates.
From practice I find circular semi-circular parabolic elliptical angular or other
similarly formed plates answer the purposes of my Invention provided they are so
formed buckled or pressed out in their centres or parts as to present the necessary
oblique and tapering deflecting planes before referred to but I do not limit myself
to any particular degrees of tapering, angularity opening or other proportions and
details of constructions as these may be modified according to requirements
without departing from the essence of my said invention In order to strengthen
support and maintain the said head plates a and b in their proper relative positions
strut and tie pieces (as at d) may be employed..
In the manner above. described a Top or Ventilator is constructed of a very.

page_text: simple and efficient character presenting every facility for the rapid discharge and
egress of smoke or noxious gases, whilst at the same time preventing any return
currents or the objectionable ingress of external air currents for owing to the
narrowness of the discharging slits or openings B provided in the top or ventilator
and the peculiar sloping or angular tapering construction and relation of the head
plates a and b the external air currents are retarded and deflected (no matter in
what direction they may impinge) so as to in no way interfere with the efficiency
of the draught or ventilation of the chimney or shaft to which it may be applied.
The manner in which the extraneous impinging air currents are caused to be
intercepted deflected and divided is represented by the direction of the arrows
shewn in the plan at Figure 3 of the drawings from which it may be inferred that
when the said air currents impinge upon the apparatus in the same plane as the
narrow transverse slits or openings B provided in the same and as assumed in the
drawing a considerable volume of air must be caused to enter the Top and thus
retard or interfere with the draught or ventilation This however is not the case
as the air currents impinging upon the apices X of the angular portions a¹ and b
become divided and deflected as indicated by the direction of the arrows so that
only an inappreciable amount of lateral pressure penetrates the openings B in the
top or ventilator while further any small amount of air in motion that may be
caused under the most unfavorable circumstances to enter the said openings is
counteracted by virtue of a certain degree of suction set up at the opposite
apices Z such ingress and egress being always in a constant proportion independent
of the varying velocity of the wind currents so that the efficient draught or
ventilation of the chimney shaft or the like is not interfered with
Figure 4 of the accompanying drawings simply represents a chimney top or
ventilator of precisely similar character to that above described but of a form suited
for being manufactured from terra-cotta or earthenware The top or ventilator may
be formed with a flat base c as shewn The letters marked on this Figure refer to
corresponding parts described in the preceding figures. Chimney Tops and
Ventilators constructed and arranged according to my Invention may be formed of
metal carthenware wood or other suitable substances or materials.
Figures 5 and 6 represent an elevation and plan respectively of a modified
construction and arrangement of chimney top or ventilator in which the said top
or ventilator is formed by a conical head casing H which may be conveniently
made in halves a. and b which are secured to the tube or shaft A in such a manner
as to leave narrow intervening slits or openings B'. B². In the drawing the said
slits or openings are shewn as extending upwards for the entire length of the top
or ventilator but they may be carried up for only a part of the distance or
otherwise varied as hereinafter described.
Figures 7 and 8 represent similar views of a further modification in which the
top or ventilator is formed with a square shaped tapering head H. provided at
the corners with four slits or openings, B³. B. B. and B. extending about only
half way up and down the angles of the top or ventilator and at right angles to
each other as more clearly shewn in the plan at figure 8 of the drawings.
It will be understood that the converse arrangements of the said slits or openings
might be conveniently adopted in either of the two last described examples; that is
to say; with reference to figures 5 and 6, four openings might be provided at right
angles to each other, extending only a portion of the way up and down the
casing as shewn in figures 7 and 8, whilst the openings shewn in the former figures
might be substituted for the arrangement shown in the latter figures.
The slits or openings as aforesaid may be variously employed providing the total
sum of the discharging areas is about equal to the effective area of the Shaft or
Chimney but in all cases the head or top must have a tapering form or be so
constructed as to present a decreasing capacity to the ascending and escaping
products of combustion or noxious gases.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into

page_text: effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is :
First, The Chimney Tops or Ventilators formed of tapering deflecting plates or
parts having slits or openings formed or provided in or between the edges of the
same substantially as and for the purpose hereinbefore described with reference
to the accompanying drawings.
Secondly, The construction and arrangement of Chimney tops or ventilators
herein before described and illustrated in figures 1 to 4 of the accompanying
drawings.
Thirdly. The construction and arrangement of Chimney tops or Ventilators
herein before described and illustrated in figures 5 to 8 of the accompanying
drawings.
In witness whereof I the said Thomas James Baker have to this my
Specification set my hand and Seal this Seventeenth day of January One
thousand eight hundred and eighty three.
THOMAS, JAMES, BAKER (L.S.)