US2425458A - Chimney cap - Google Patents

Description

F. B. CHARROIN CHIMNEY CAP Fil ed Sept. 7. 1943 Aug. 12, 1947.

XNVENTOR. Frank 3. aka/min BY WM W ATTORNEY Patented Aug. 12, 1947 UNITED STATES PATENT OFFICE CHIMNEY CAP Frank B. Charmin, Bellingham, Wash, assignor to Arthur B. Charmin, San Diego, Calif.

2 Claims.

This invention relates to chimney caps, and particularly to such caps for providing a vacuum in the chimneys and for increasing the upward drafts therein, and for preventing downward drafts. a

In the use of chimneys for fires, and especially for dwellings, troubles are frequently occasioned by smoke from stoves etc., being driven down the chimneys, or prevented from flowing upward by wind currents blowing across the same.

It is therefore among the objects of this in-- vention to provide a cap with a plurality of upward sloping top and bottom plates, spaced apart one over the other, for attachment to tops of chimneys, for diverting wind currents upward from over the flues in the chimneys, and for preventing such currents from entering the fiues, and for providing suction and vacuum in tops of the fiues for increasing the rapidity of the flow of smoke therefrom.

With these and other objects that may be here! inafter stated, I have illustratively exemplified my invention by the accompanying drawings, of which:

Figure 1 is a perspective view of the cap mounted on a chimney;

Figure 2 is cross section view of the same. Like characters on the different figures represent like parts.

A, indicates the upper portion of a chimney, with flue B, therein. C represents the cap generally, and D indicated a rod and bar for connecting the cap by attachment to an eye bolt E, in the cap. The parts of the cap are more particularly described as follows: 3 indicates a band or frame of suitable dimensions for adjustment over the upper end of the chimney for maintaining the cap in position. 4- -4 and 5 represent strips of suitable material for supporting posts at corners, for sustaining verticle baflies, as 6, l, 8 and 9, and also roof plates as II], II, l2 and I3.

Floor plates I4, l5, I6, and I! are affixed to the top of the chimney with their outer edges approximately in line with the outside of the chimney walls, and slope inward and upward on an angle approximately 45 degrees to points approximately in line with the interior walls of the chimney flue, and there terminate to leave an outlet 23 for the smoke to escape from the flue beneath. There are preferably four of such plates extending in opposite directions, or inward from each side of a square chimney. The roof plates are of similar dimensions and mounted on the same angles and extend from points in flue, the baflies are extended downward verti-v cally from the outer. edges of the roof plates to approximately half the distance toward the outer edges of the floor plates, and thu provide a chamber behind the respective bafiles, and leaving narrowed ports for entrance of side wind currents, indicated as I8, I9, 20 and 2|. Such arrangement of the plates and baflies is important for changing the character and direction of currents entering the ports, in order to provide suction in the flue and draw the smoke upward therefrom and not hinder the escape of smoke from the chimney. Where currents of air or wind are permitted to cross the top of the flue of a chimney, they place an obstructon to the upward flow of smoke and prevent any suitable draft in the chimney for increasing combustion in a, fire beneath. The position of the battles across the upper portion of the passageways, causes the incoming air currents to flow upward in a circular movement behind the baflies and tend to form a partial vacuum behind the bailies which tends to make the current somewhat expanded or thinner and to hug the roof plate and flow upward from the opening 22 above the flue thus forming further vacuum to draw the smoke upward. Chimneys provided with this form ofand behind the bafile 8, in general location of the numeral 9. The shaded area behind the baflie 8 may be deemed to indicate where the current of air i expanded by suction and caused to swim upward similarly as a current of a stream of water is caused to swirl and form a whirlpool behind a rock or other obstruction to its regular course, and thus swing in behind the obstruction in a new line of travel. Repeated experiences with the use of this form of cap have established their efliciency, above all other known types.

The baffles also tend to check the flow of any air currents that may be blown obliquely down ited beneath the baflles, which would slow up the velocity of the current thereby permit the outward flow of smoke from the flue. I

The band 3 is also important for retaining the upper tier of bricks from separating from exposure to the weather, and the assembly adds to the architectural view of the chimneys. The frame and caps are preferably formed of sheet metal, and for the most part may be integral with each other. In use on round chimneys, or

stacks, the band 3 would preferably be rounded also. In use of the caps, the greater the wind, the greater the suction and draft in the dues.

Chimney troubles are generally occasioned by smoke being driven down the chimney by the wind currents flowing downwardly, and it means can be provided for utilizing the wind currents from either side of the cap to create within the cap a vacuum efiect on the rising smoke and to utilize the down flow of the air through the top of the chimney to accelerate the lateral currents, the tendency of the smoke to rise in the flue is increased and the retarding of the flow of such smoke is materially reduced if not entirely obliterated.

The provision in the improved cap of floor plates I4, I5, I6, and I! in parallelism with the roof plates III, II, l2, and I3, and at an angle of 45 to the axial line of the chimney cap, and the formation of the openings I8, I9, 20, and 2| at an angle to the plates I4, I5, I6, and I'I with such openings extending fromthe bottom edge of the floor plates and of a materially less vertical dimension as compared with that of the floor plates, the air currents entering an opening impinge the adjacent floor plate and are compelled to flow upwardly at an angle of 45 and while confined between the particular floor plate and the overlying roof plate and then upwardly in the channel between the floor and root plates, entirely beyondany direct efi'ect from the air entering the opening in the side wall, and then over the top of the floor plates toward and through the opening in the opposite wall. There is thus created a vacuum efiect in the chimney flue to materially aid in pulling the smoke up the flue to mingle with the air and escape with it through the opening opposite that by which it entered. The velocity ofthese air currents is reduced by the expansion between the roof and floorplates. Therefore, when the downward current strikes from the top on the windward side, from which they must, they strike the under side of the roof plate and are diverted downwardly between the plates and carried out on the lower lee side of the chimney to thus create a substantially perfect siphon.

Having described my invention, I claim as new:

1. A cap for chimney flues comprising four 60 side plates to fit over and extend above the upper end of the chimney flue, the upper ends of the side plates being inclined toward each other forming bafiles and defining a central outlet, floor plates within the cap rising to an inward angle of approximately 45 from the side plates at the junction of such side plates and chimney flue,

4 the floor plates terminating at the upper end to define an opening in line with but of slightly less dimensions than the flue, each floor plate being in spaced parallelism with an inclined upper end of a side plate, each side plate being formed with an opening the same distance below each baflle of nearly the full width of that side plate and of a vertical dimensionapproximately one-half only of that of the adjacent floor plate whereby the air currents entering an opening are directed against the adjacent floor plate and caused to flow upwardly between the floor plate and the top of the cap then over the opening formed by the upper ends of the floor plates above the flue and down over an opposite floor plate and out the opposite opening in the side plate to thereby cause a vacuum pull on the smoke in the flue, the downward flow of air through the cap outlet being directed to increase the vacuum flow to induce a siphon effect on the smoke in the flue.

2. A chimney cap including a body having four walls shaped to fit over and rise above the chimney proper, said cap having an outlet formed by inwardly inclined baflle portions of the upper ends of the walls of the body, floor plates rising in the body from the edge of the chimney proper at an inclination of approximately to the axial plane of the cap and terminating at their upper ends to define an opening vertically coincident with but spaced from the outlet, said outlet and opening being in line with the chimney flue the sides of the body being formed with inlets in each 01 said four sides the same distance below said bailies and in transverse alignment with an adjacent fioor plate with their lower margins coincident with the lower edge ofthe adjacent floor plate, the vertical dimensions of each of said inlets being approximately one-half that of the adjacent floor plate.

, FRANK B. CHARROIN.

REFERENCES CITED The following references are of record in the 45 file of this patent:

UNITED STATES PATENTS Number Name Date 179,421 Merrick July 4, 1876 684,170 Barnes Oct. 8, 1901 1,337,731 Speaks Apr. 20, 1920 192,202 Van Wie June 19, 1877 319,074 Crompton June 2, 1885 319,750 Sexton June 9, 1885 744,570 Le Beau Nov. 17, 1903 1,068,257 McCall July 22, 1913 4,117 Hamann July 22, 1845 1,014,969 Matchell Jan. 16, 1912 FOREIGN PATENTS Number Country Date 572,159 France Feb. 15, 1924 502,466 Germany Nov. 27,1930 551,966 Germany June 8, 1932 47.687 Norway Mar. 24, 1930 414.770 France June 27, 1910 393 Great Britain 1903

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