IMPROVEMENTS APPLICABLE TO CHIMNEYS OR SHAFTS USED FOR PURPOSES CONNECTED WITH HEATING AND VEN- TILATING
Year: 1877

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LETTERS PATENT to James Hamilton, of Rochdale, in the County of Lancaster,
Ironmonger, for the Invention of "IMPROVEMENTS APPLICABLE TO CHIMNEYS
OR SHAFTS USED FOR PURPOSES CONNECTED WITH HEATING AND VEN-
TILATING."
Sealed the 7th August 1877, and dated the 28th February 1877.
PROVISIONAL SPECIFICATION left by the said James Hamilton at the
Office of the Commissioners of Patents on the 28th February 1877.
JAMES HAMILTON, of Rochdale, in the County of Lancaster, Ironmonger.
PROVEMENTS APPLICABLE TO CHIMNEYS OR SHAFTS USED FOR PURPOSES CONNECTED
WITH HEATING AND VENTILATING."
IM-
My Invention refers to the prevention of what are commonly smoky chimneys,
and in other cases, as in ventilating shafts, the prevention of a down draught.
To take the case of a simple chimney top, I place above it a slab or disc, and so
far that is in ordinary use; but according to my Invention I place beneath it
and below the orifice of the chimney another slot or disc, and by preference I so
arrange the apparatus that when the wind is blowing at an angle downward it
shall take a course at about forty-five degrees, while the lower disc or slot prevents
the wind when blowing upwards from being deflected into the mouth of the
chimney.
In the case of flat roofs the roof itself may constitute the lower disc or slab,,the
upper being if desired supported thereby; and in cases where there are several
chimney tops ranged side by side one upper and lower disc or slab may be used to
answer for the whole range.
The above-described principle may be adapted to revolving chimney tops by
forming the revolving wings with upper and lower discs connected together by
side plates, the whole being capable of turning upon a spindle carried, by the
chimney top, and for the purpose of allowing the sweeping brush to pass the orifice
of the chimney I support the said spindle by a forked.part.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Hamilton in the Great Seal Patent Office on the 28th
August 1877.
JAMES HAMILTON, of Rochdale, in the County of Lancaster, Ironmonger. "Iм-
PROVEMENTS APPLICABLE TO CHIMNIES OR SHAFTS USED FOR PURPOSES CONNECTED
WITH HEATING AND VENTILATING."
My Invention consists in a method of preventing down drafts in chimnies or
ventilating apparatus. For this purpose I place a disc or other such surface above
the orifice of the chimney or ventilating medium, and so far the apparatus is not
new; but, according to my Invention, I adapt beneath it and below the said orifice
a second disc or other such surface, the effect of which arrangement will be under-
stood from the following description, reference being had to the accompanying
Drawing; and I shall, in the first place, use Figs. 1 and 2 as diagrams to explain
the principle of my Invention.
At 1 is the top of a chimney or ventilating shaft, and at 2 the orifice thereof,
above which is a disc 3 supported by arms 4, and below the said orifice is another
disc 5 attached to the flue 1. The two discs or plates 3 and 5 are a distance apart
equal to the diameter of the flue 1, which extends upward to halfway between the
said discs or plates, and their circumferences form an angle of 45 degrees with the
edge of the flue, as shewn by the dotted line a, b, which it will be perceived strikes
the centre of the disc 3, and a gust of air passing in that direction will therefore
.be deflected clear of the other side of the flue 1, as shewn by the dotted line c, d,
..while the top disc 3 acts also in the ordinary manner, it being, as before stated, a
well-known apparatus when used by itself. This arrangement I call in full pro-
portions which I use for purposes of ventilation, but as it involves discs of con-
siderable diameter, and inconveniently so for chimnies; I'adopt another arrangement
which I call in reduced proportions, and illustrate at Figs. 3 and 4. In this case
the bottom disc 5 is as before, but of smaller diameter; the top disc 3, however, is
of a dished form, and the line e, f, passing at an angle of 45 degrees, strikes tho
contre as in the former instance, and is in like manner deflected; by adopting this
dished form it will be perceived that I am able to maintain the same principle as
that before described, but with discs of less diameter.
The above-described arrangement involves an angle of forty-five degrees, but I
"do not limit myself thereto, as it may be varied, so long as the principle of using
top and bottom discs is adhered to.
Figs. 5 and 6 shew a modification of my Invention, in which the object is to
gain an increased area of outlet.
To the flue 1 is attached as before the bottom disc 5, and at 3 is the top disc
answering to that of the formerly-described Figs, and carried by the supports 4.
This disc, however, is formed with a short flue piece 1* surmounted by a third disc
3*, which thus becomes a second top plate. By this arrangement two outlets; 6
and 7 are provided, and the area is therefore increased.
Fig. 7 shews in side view an arrangement which may be adopted for several
flues together; Fig. 8 is an end view thereof, and Fig. 9 a plan view; at 1, 1ª,
1b, are three flues, their upper ends passing through a disc or plate. 11, and- sur-4
mounted by a curved disc or plate 12, the said discs or plates 11, 12, being united by
angular blocks 13, and they, therefore, answer to those formerly described. This
arrangement may be used for ventilating ridge roofs, as in the cases of green-
houses, conservatories, or sheds, and for such purposes. A continuous longitudinal
flue may be adopted instead of separate flues like those shown at 1, 1ª, 1b.
Figs. 10 and 11 shew in elevation and plan view another form of my Invention.
At 1 is the flue which carries the bottom disc or plate 5, and at 3 is the upper disc
or plate, the two being made, however, in this instance with three projecting parts,
14, 14, 14b, connected together by side pieces respectively, and thus forming
separate tubes.
5

page_text: Figs. 12, 13, and 14 shew in elevation end and plan views how my Invention
may be employed in the form of a cross. At 1 is the flue forming the main
upright part, and passing into the rectangular part 15, the top and bottom parts
3, 5, of which constitute the discs or plates which constitute my Invention.
The part 16 is of course closed at bottom, and is merely added to complete the
cross, and in like manner other designs may be caused to embody my Invention ;
and it will be evident that the apparatus may be round, square, or of any other
desired section.
I have shewn my Invention applied in a vertical direction, but when required it
may be placed horizontally, or at any desired angle.
Having thus described the nature of my said Invention, and the manner in which
the same is to be performed, I desire it to be understood that I claim as secured to
me under the above in part recited Letters Patent, and for the purposes above set
forth, the combined use of the discs, plates, or other such apparatus, one on one
side and the other on the other side of the orifice of the flue or other such part,
substantially as described.
In witness whereof, I, the said James Hamilton, have hereunto set my hand
and seal, this Twenty-seventh day of August, in the year of our Lord One
thousand eight hundred and seventy-seven..
JAMES HAMILTON. (L.S.)