Flue conduits with heat transfer elements therein
US 2950740 A
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Aug. 30, 1960 FLUE CONDUITS WITH HEAT TRANSFER ELEMENTS THEREIN Filed. April 29, 1957 .IJVYVENTOIL OSCAR L. BOOK BYW ATTORNEY.
states Patent Patented Aug. 30,1960
fthe ue and the Water surrounding the flue is effected.
It isycustomary in water heaters to provide a com- -bustion chamber below the tank and a flue from the combustion chamber passing u-p through the tank andy the water therein whereby the heat from the hot gases heats the vwater surrounding the flue. The object of the invention is to provide a flue of such construction as to effect 1a better heat vexchange between the hot gases passing up through the ue vand the water surrounding the iiue.
A still more: specific object isv to provide a flue with baie plates therein of such construction as to provide a maximum of heat exchange.. from the gases to the Water without substantiallyimpeding the upward travel of the hot gases. met
The invention is an improvement over the heat transfer tine shown in my prior Patent 2,687,747, August 31, 1954.
In the above patent a flue for the purpose indicated is shown wherein baffle plates are secured within a heating flue. In this patent the baffle plates lie in a horizontal position. In carrying out the objects of the instant invention the bafe plates are set at an angle. It will be obvious that with the new arrangement a greater number of bafi'le plates can be secured in the flue and thereby eifect a greater degree of heat exchange from the lhot ue gases to the water in the tank. In the new arrangement the baille plates are tilted so that at their inner ends one 'may overlap the preceding one in a series so that not only may a greater number of baiiies be used but the plates will create less back pressure on the gases passing through the ue. In the arrangement shown in the patent the baiiles lay at with a result that the hot gases passing about them passed both sides of them. This tended to impede the passage of the gases. With the baffles arranged in a tilted manner as shown and arranged in a spiral around the inner side of the ue the gases travel rapidly in a spiral up the ue in'such a manner to allow a relatively large output of heat.
Another advantage lies in the fact that baies of uniform width can be used instead of having the ends tapered. In forming the baiies it is easier to cut off straight pieces of strip material than to make tapered ones.
Further objects and advantages will become apparent from the description which follows and from the illustrations in the drawings, in which Fig. 1 is a vertical section of a water heating boiler showing my invention incorporated therein;
Fig. 2 is an enlarged partial section of the heat transfer tube; and
Fig. 3 is a top view of the heat transfer tube and may be regarded as a section on line 3 3 of Fig. 1.
In the drawings numeral indicates a conventional Water tank or boiler having a surrounding casing 11 confining a heat insulating material 12 between itself and the tank 10. The tank 10 preferably has a rounded top 13 and a rounded bottom portion 14. The walls of the tank extend down below the bottom portion 14 to provide a combustion chamber 15, the combustion chamber containing the usual burner elements essential for heating the boiler. A ue or tube 17 has its lower inlet end secured in the bottom end 14 and its upper outlet end secured in the top 13 ofthe tank, the flue extending up through the water in the tank. The ue is suitably sealed against leakage as by welding to the top and bottom ends of the tank.
Baie plates 18 are secured at their ends to the inside of the tine 17 and these batiie plates are arranged to extend in a spiral up through the flue as shown in Fig. 2. These battle plates are set at an angle to the axis of the liuc in a direction counter to the direction of their spiral pattern and with their lower surfaces which face theV inlet end of the ue slanting upwardly toward theoutlet end of the flue. The flue gases passing up through the iiue will contact the tilted battles and will be given a spiral movement in a direction counter to the spiral arrangement of the baffles. Because of the tilted arrangement of the baffles a better heat transfer between the hot gases and the baffles will be effected resulting in a better heat exchange between the gases and the water in the boiler.
It is to be understood that the present invention is not confined to the specific form thereof herein illustrated and described and that the principles thereof may be embodied in various moditiced structures within the scope of the appended claims. For example, while the heat transfer tube has been shown and described as for use in a water boiler it is not necessarily limited to this use. It may be used wherein a hot fluid, gas or liquid is intended to heat a surrounding uid, gas or liquid or possibly a solid material wherein the heat from the iiuid in the ue is transferred through the walls of the flue to the media surrounding the flue.
1. A heat transfer device comprising a tube having a tluid inlet end and a uid outlet end, a plurality of substantially fiat batlies for heat exchange contact with iluid flowing through the tube, said batlles being secured to the inner wall of said tube in heat exchange relation and projecting inwardly a substantial distance toward the central axis of said tube, the said .baffles having opposed surfaces facing respectively toward said inlet and outlet end, the said baies being arranged successively along the inner wall of said tube in a spiral pattern andthe said baiiles being tilted at a substantially uniform angle in a direction counter to the direction of their spiral pattern with their inlet end facing surfaces inclining toward said outlet end whereby to guide uid ow through the tube in a spiral path counter to the direction of the spiral pattern of said baies.
2. The device of claim 1 wherein the bales are elongated and are end connected to the inner wall of the tube.
References Cited in the tile of this patent UNITED STATES PATENTS 641,911 Wilkins et al Jan. 23, 1900 1,451,272 Robinson Apr. 10, 1923 1,662,178 Yuille Mar. 13, 1928 2,079,144 Appa May 4, 1937 2,273,157 Tenny Feb. 17, 1942 2,281,206 Schoen Apr. 28, 1942 2,290,784 Turpin July 21, 1942 2,687,747 Bock Aug. 31, 1954 2,756,032 Dowell July 24, 1956 FOREIGN PATENTS 830 Great Britain of 1860 760,701 France Dec. 14, 1933