US 1946568 A
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Feb. 13, 1934. i w BUTLER ET AL 1,946,568
DRAFT CONTROL DEVICE Filed Dec. 7, 1931 2 Sheets-Sheet l l/Wo m Feb. 13, 1934.
W. L. BUTLER ET AL DRAFT CONTROL DEVICE Filed Dec. 7, 1931 2 Sheets-Sheet 2 anal UNITED STATES DRAFT CONTROL DEVICE William L. Butler and Henry F. Hillard, Salt Lake City, Utah; said Hillard assignor to said Butler Application December '3, 1931. Serial No. 579,484
1 Claim. (01. 23645) Our invention relates to draft control devices Figure 7 is a section of the support block on and has for its object to provide a new and efline '77 of Figure 2.
ficient control for controlling the draft in a fur- In the drawings we have shown our device as nace pipe, preventing back draft, and keeping the made of a rectangular casing A, having an inlet pull from the combustion chamber constant. pipe 1 in one end thereof and an outlet pipe 2 in 00 A further object is to provide a device for reguthe opposite end thereof and with a partition 3 lating the draft in furnaces which by automatic dividing the interior into two chambers B and C. action prevents reverse or back draft, opening The partition 3 is secured to the top of the casthe draft from the furnace into the surrounding ing box A and extends down to near the bottom atmosphere when there is a back draft in the flue. 0f the box where it is bent at an angle with the B5;
Astill further object is to provideadraft control bent side 4 parallel to the base of the box and which will save fuel for the user and which elimithe bent side is then secured to the inlet end 5 nates the danger of asphyxiaton due to blowing 0f the box A below the level of the inlet pipe 1. out of the flame and allowing the gas to escape In the bottom of the box A under the partition 4 unb ed we provide an air vent 6 and adjacent to the vent 70 A still further object is to provide a constant We provide tWO Spaced apart V t ca rods 7 draft in the combustion chamber to furnish oxywhich rods carry a closure plate 8 with e p ate gen for combustion in a constant quantity result- 3 Over the Vent 6 and With elongated S ots 9 n the ing in the fuel being completely burned, effecting P e 8 around the rods 7 50 that When the plate savings ver other methods now used ls ralsed Suction the bOX the plate raise A Still further object is to provide a flue draft without friction as the slots 9 will allow the plate control which will draw relief air from the furnace to ralse on h rods 7 Wlthout touchmg them in room into the stack only when the fire is burning, x and m Order 1 that the plate 3 and then only in the exact amount necessary to @1565 Wlth h back slde hlgher than the frnt maintain the minimum required draft pull on the slde We provlfie i Welght 10 on the slde of so orifice the plate 8 in which the holes 9 are formed.
A still further object is to provide a balanced Through the top A1 Of the casmg A We then control for controlling the flow of draft from the vlde ouflefi opemng or PQ 11 and h furnace through the flue, preventing back draft ggg lgg g gj gf f t gg g g i fi s g 8 by f g g the flue i furnace i Vhen closure device D mounted thr ugh of; tc i g e the 5 back a occurs an provi ing a prac Ica y rictionless control eliminating the necessity of undue 2 :2 3 3 2 55 ggg'gg gzfiii gigg gfizi fig.
suction or back draft being necessary to operate the other polit is open An adjustable plate 15 the device.
These objects we accomplish with the device ilif ggg 32 23 95??? 3 5 2 a ga bifi 9o lustrated in the accompanying drawings in which from the chamber B into the chamber 0 This s milar numerals and letters of reference indicate is Set when the device is installed by making the like pa throughout theseveral Yiews and as draft the correct pull for the fire being used and 7 described i t Speelfieetloh fol'mmg a Part of the plate 15 is then looked in place by the bolts 95 this application and pointed out in the appended 16. claims. In the d a in which We have Shown The plates 13 and 14 of the closure D are made the best and most preferred manner 01' building as shown, at an obtuse angle to each other, but our invention. they do not necessarily have to be made at such an Figur 1 is a Perspective View Of the device, Darts angle. Dividing the space between the two plates 100 ShOWIl by dotted lines and parts shown 0111', away. into two equal angles and extending outwardly I l Figure 2 is a plan view of the device. therefrom we provide a counter balance rod 1'7 Figure 3 is 61 Vertical Section on line of carrying an adjustable weight 18 with a set screw Figure 2. 19 provided for setting the weight at the proper Fi 4 is an end View Of Figure position for balance of the two plates. On the 105 Figure 5 is a side elevation of the pivoted conback side of the two plates at their juncture we 7 trol plates provide spaced apart support blocks 20 and 21,
Figure 6 is a plan view of the plate for covering one at each edge thereof, said blocks being prothe draft regulation opening in the bottom of the vided with threaded holes therethrough, through device. H which holes we provide adjustable externally 1119 threaded pivot points 22 and 23, which points are carried in blocks 24 and 25. The said blocks 24 and 25 are mounted on the top side of the box A adjacent to the opening in the top thereof and said blocks are provided with tapered indentations 26 in the top side thereof in which the pivot points rest to support the two plates pivotally in the openings. The weight and rod extend upwardly and toward the outlet end of the box A. The plates are set in the device and the weight adjusted to close the port 11 and at such abalanced position that draft through the device will not afiect the port but so that back draft will instantly close the port 12 and open the port 11 allowing the consumed gases to escape from the box A through the port 11 into the room around the furnace.
The operation of the device will be as follows:
When the draft in the stack is equal to or lower than a predetermined required amount which is fixed by the weight of the vent plate 8, exhaust gases from the combustion chamber of the furnace will pass through the inlet pipe 1 into the chamber 13, through the port 12 into the mixing i chamber C and out to the stack through the outlet pipe '2.
When the draft of the stack. is greater than a predetermined required amount which is fixed by the weight of the plate 8, exhaust gases will pass through the chamber B through the port 12 into the chamber B and out through the port 11 into the surrounding atmosphere. The back draft will close the port 12 by pressing the plate 14 thereagainst, or if the draft condition is neutral the buoyancy of the gases from the furnace will lift the plate 13 closing the port 12 and opening port 11. To normally adjust the proper amount of gases from the combustion chamber of the furnace and carry them out the stack a certain definite draft must be maintained in the chamber B and this is controlled by the side of the port 12 by the plate 15. The intensity of draft in the chamber C is maintained by the opening of the vent 6 by raising the plate 8 by the suction in the chamber. Any increased velocity or suction through the stack will open the plate 8 more from the vent 6 admitting relief air into the chamber C.
With this device connected between a stack and outlet of any combustion chamber the air and fuel supply to the combustion chamber may have their respective controls so set that proper combustion is effected when exhausting all of the products of combustion through the opening 11. At this condition there will be uniform absolute pressure in the chamber B. To normally discharge the products of combustion to the stack the port through the partition 3 and the weight of the vent plate 8 are so adjusted that the controlled degree of draft in the chamber C will be that degree necessary to permit just the proper flow of gases through the port 12 to maintain the same absolute pressure in the receiving chamber B as when the products of combustion all passed through the vent or opening 11. With such a setting the products of combustion may freely exhaust into the furnace room through the port 11' discharging only harmless carbon dioxide and water vapors therethrough.
A rotating balance is maintained in the plates 13 and 14 and the weight 18 by proper adjustment of the said weight on the rod 17.
When installing the device the plates are adjusted to a rotating balance and the pins are then slightly withdrawn so that the weight will normally close the port 11 and leave the port 12 free.
Having thus described our invention we desireto secure by Letters Patent and claim:
A draft control for furnaces "comprising a caslng divided into inlet and outlet chambers with a port therebetween and with a port from the inlet chamber into the atmosphere; pivota-Ily supported integral counter-balanced plates carried on said casing adapted to close the atmospheric port and open the port between the chambers or open the atmospheric port and close the port between the chambers as the draft through the furnace flue fluctuates; and a draft responsive plate controlling a vent in the outlet chamher to draw extra air into the outlet chamber when the draft through the flue is increased above that predetermined amount required for complete combustion in the furnace.
WILLIAM L. BUTLER. HENRY F. HILLARD.