CA1182013A - Apparatus for controlling flow of combustion products - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Apparatus for cooperation with an associated flue having a first axis extending away from a point proximate to an associated combustion chamber which includes a funnel shaped member having first and second ends. The second end is larger than the first end. A damper is disposed in the associated flue which has a generally central bore. The damper is mounted in the associated flue for rotation about a second axis which is generally perpendicular to the first axis and the funnel shaped member is mounted with the first end higher than the second end and with the second end extending through at least one wall of the associated flue. The mounting for the funnel shaped member may comprise a plurality of elongated members extending radially from the funnel shaped member to the associated flue. In another form of the invention a first duct is disposed within a second duct which is in fluid communication with an associated flue. The first duct may be rectangular in cross section and generally planar members may be selectively pivoted to restrict flow intermediate the first and second ducts. The first duct will ordinarily have no restriction on the flow of exhaust gases other than the restriction inherent in the inner duct.

Description

~ ~820~3 BACKGROUND OF' THE INVENTION

The invention relates to apparat~s for burning wood and the like and particularly to apparatus for contro.Uing the flow of combustion products.
While the invention has particular app.licat.ion to controlLl.ng the flow of combustion products from stoves which burn wood it will be understood that it also has appLication to other app.~Lratus which burns other fuels.
The prior art apparatus for controlling the flow of combustion products from a combustion chamber has not resulted in optimum safety and ef.fic.iency of operation. The prior art apparatus includes the well known damper which iSJ of cou.rse, mereLy a disc shaped member which is mounted for rotation on an elongated member which extendsthroughthes~desoftheflue. Thedamperhas the fhnction of varying ~he nate at which the combustion products are allowed to escape from a combustion chamber and hence also to con~olthe amount of air which can be drawn into a combustion chamber. Such prior art apparatus has not been whc~ly satisfactol~y because the apparatus has been particularly vulnerdble t,o the accumulation of flamable matter such as creosote on the interior surface of the flue. It i.s known that the accumulation of combustible matter on the interior of t,he f~ue is corsiderably reduced i~ the temperature of the flue is maint ined at an elevated temperature. At least some people believe that a temperature of 400 degrees F is nece~ary to avoid the accumulation of undesirable combustible products such as creosote and the like.
The appl icant has ~ound that a pri mary reason that flue ducts are not raised to a sufficiently high temperature (to avoid the accumul~tion of creosote and other combustible materials ~n the f~e) is tha~ the velocity of the gases is not suf~cient.
It is a p~imar~ object of the invention to provide combustion gas control apparatus which will have flow characteristics which wi~l tend to avo.id '.'~

1 1~2013 the accumukation of combustible combustion product~, in the f~Lue.
It ~c~, another object of the invention to provide apparatus which will maintain a relatively high temperature in the exhaustgas duct work, even during periods of low flow of combustion gases f~om a f`lre disposed in a combustion cham ber.
It is another obJect of the invention to provide apparatus which wiU be simple to install in existing fllle structures.
It is yet another object of the invention to provide apparatus which will be inexpensive to m anufacture.

SUMMARY OF THE INVENTION

The foregoing objects and other objects and advantages which shall become apparent from the detailed description of the preferred embodiment are attained in an apparatus for cooperation with cm associated f~e, having a f~rst axis extending away f~om a point proximate to an a sociated combustion chamber. The apparatus includes a ~unnel shaped member having fir.st and second ends. The second end may be larger than the first end. A damper is disposed in the associated flue having a generall~ centr~l bore. Means are provided for mounting the damper in the associated ~l~e for rota~i-on about a second axi~ which is generally perpendicu~r to the first axi~s, and means are provided for mounting the funnel shaped member with the fir.st end higher than the second end and with the second end extend:ing into the damper.
In one form of the invention the means for mounting the damper- may co m prise at least one rod shaped m e m ber extending through at least one wa~l oE
the associated flue. The means for mounting the funnel shaped member may comprise a plu~lity of elongated members extending radially ~om the funnel shapedmembertotheassociatedf~e. Theapparatusmayfurtherinc~def~rst 1 ~82013 and ~second gener~d~ly planar members carried in the æcond end of the fùnne~L
shaped m e m ber. The generalLy planar m e m bers m ay be m ount~d for f luid sealing engagement with the interior of the second end of the flJnnel shaped member.
The ~irst and .second generally planar members may be disposed with a slot shaped space intermed:'ate the members. The apparatus may further include a duct extending from and in fluid commu~ication with the first end of the furmel shaped member. The duct extends substantia~y the entire axial extent of the a sociated flue above the funnel shaped member. The f5rst and second general~y planar members may be semicircular.
In one form the apparatus may cooperate with a flue, having a flrst axis extending away from a point proximate to an associated combustion chamber.
A furnel shaped member has f~rst and second ends. The æcond end may be larger than the first end. A damper may be disposed in the associated flue having a generd~ly central bore. The means for mounting the damper in the associated flue may allow rotation of the damper about a second axis which is generally perpendicular to the first axis. The mear~s for mounting the f~mnel shaped m e m ber may carry the funnel shaped me m ber with ~e first end higher than the æcond end and with the second end extending into the damper. The means for mounting the damper may comprise at least one rod shaped member extending thr~ugh at least one wa~ of the flue. The means for mounting the flmnel shaped m e m ber m ay co m pri~se a plurality of elor~ated m e m bers extending radi~lly from the funnel shaped member to the flue.
The apparatu~s may further include f~rst and second generally planar members carried in the second end ofthefunnelshaped member. The generaJly planar members may be mounted for flllid sealing engagement with the interior of the second end of the funnelshaped member. The first and second gene,ral~y planar members may be disposed with a slot shaped space intermediate the 1 1~20~3 members. A duct extends f~om and in fluid COM m unication with the f5rst end of the funnel shaped member. The duct extends substantially the ent~re ax~l extent of the flue above the ~lnnel shaped member. The first and second genera~ly planar m e m bers m ay be se m icircular.
In anot,her embodiment of the invention an innerflue rnay extend along substantially the entire axial extent of the associated flue. The inner flue may define first and second parallel paths which are re~spectively in.slide of and outside of the inner flue and means for modulating the flow through one of the flow paths. This e m bodiment may further include means for mount;ing the inner flue in generally coaxial relationship with the associated flue. The mear~s for modulating may comprise a pair of genera~ly planar members. The generally p~Lnar me mbers may each be pivotally m ounted. The inner flue may have a generc~y rectangular cross ~section.

BRIEF DESCRIPTION OF THE DRAWING

Figure 1 is a partially schematic elevational view of apparatus in accordance with a ffrst form of the invention;
Figure 2 is a sectional view along the line ~2 of Figure 1;
Figure 3 is a bottom view of a portion of the apparatus of Figure 1;
Figure 4 is a perspective view of a second embodiment of the invention shown in ooopera'cing relationship with an associated ~replace;
Figure 5 is a partially schematic sectional view taken through a vertical plane of the second embodiment of the inven~ion; and Figures 6 and 7 are top views of apparatus which is similar to the second embodiment of the invention in Figures 1l and 5.

1 ~2013 DESCRIPTION OF THE PREFERRED EMBOD:tMENT
__ ___ __ ____ _ _ _ ___ Refe~ng now to Figures 1, 2~ and 3 there is shown a combustion gas control appardtus 10 which includes a first axial section 12 and a second axial section 1l1. The second axial section 14 has a cylindrical cross secticn which is larger than the cross section of the first axial section 12~ In one e m bodim ent of the invention the second axial section 14 has a diameter of 10 inches and the first axial section 12 has a diam eter of approximately 8 inches. A damper 16 is mounted for rotation on pins 18, 18 w~Lich extend through the wa~l of the second axial section l4 of the flue. A handle 20 is provided for manua~1y rotating the damper 16. The center of the damper 16, in one form of the invention, is provided with a bore 22, which in one form of the invention, wiU have a diameter of four inches. In one form of the invention the bore 22 may have a peripherally disposed seal 24 which may be manufactured oE asbestos or other material which will provide fluid sealing and which will not be vulnerable to the temperatures which may be encountered within the flue.
Disposed in substantially fluid sealing engagement with the seal 24 is the lower or second axi~l extremity 23 of the funnelshaped membe~ 24. A first axial extr~mity 26 of the f~mnel shaped member 24 has a diameter which is smaller than the second axial extre mity 23. In the illustrated embodim ents the nnel shaped member 24 is rotation~ly symetrical. In other embodiments the ~unnel shaped member 24 may have one side which is generally vertical to improve clearance with respect to the bore 22 of the damper 160 Refe~ing now particularly to Figure 3 which is a bot~om view of or~:y 'che f unnel shaped member 24. A pair of semicircul~r generally pL~nar me mbe~s 28 ar~ fixed in f~id tight relationship about the outer arcuate extent thereof to the second axial extremity 23 oî the flunnel shaped member 24.
-- As best seen in Figure 1 the funnelshaped member 24 is ~xed at the f~rst axi;~1 extremity 26 to an e~longated duct 30 which l~ dispose~ in gener~lly coaxial reL~tionship with the f`irst axial extre m ity 12 o~ the flue A ring 32 m ay be disposed about the elongated duct 30 and may cooperate with e~longated members 34, 34 which extend to a portion of the ~lue, such as the f~t axkal extre m ity 1 2.
In oper~tion the damper 16 may be rotated to the posikion shown in Figure 2 wherein substantia~ly allthe combustion gases being removed from the combustion chamber will be directed through the second axial extremity 23 of the funnel shaped me mber 24 and out through the duct 30. The relatively rapid flow of a sma~l amount of gas through the duct 30 and also through the funnel shaped m e m ber 24 will tend to raise the f~mnel shaped m e m ber 24 and duct 30 to a higher air te m perature than w ould be attained in the flue axi~lsectiors 12, 14.
This fo~lows because the heating effect of the combustion gases (not shown) will be more attenuated in the much larger flue duct. In addition the larger duct wi~l repreænt a much ~er heat sink than the smaller duct.
The lower axial extremity 36 of the gas control apparatus 10 is, of course, in fluid com munication with the associated combustion chamber.
During per~ods when the combustion chamberis being charged with anadditional quantity of wood, the damper 16 will be rotated f~om the position shown in Figure 1 to a position wherein the flow is allowe~ past the damper 16 and thr~ugh the annular opening intermediate the axialsections 12 and 14 of the flue on the one hand, and funnelshaped member 24 and the duct 30 on the otherhand. It will thus be seen that substantial quantities of combustion products will be carried away and the danger of passing smoke into the room in which the flue is located is minimized. It will be fur~her understood that the asbestos seal 24 al1Owssu~cientdeflectionto maintainthe~uidsealaroundthelowerorsecond axial extremity 23 and aLso that the bore does not represent a subs~antial physical constraint on the movement of the damper 16.

~ ~8~)13 In .some forms of the invention the genera~ly ~lanar members 28, 28 may be rectangular or square or some other geometric form or may be omitted entirely from the apparatus. Ordinarily in those embodiments which include these members a small gap will be provided as generally indicated in Figure 3.
ûrdinarily the a~ l portion of the flue im mediately surrouncling the damper 16 wi~l have a cross section which is larger than portions of the flue ~ore remote f~om the associated combustion chamber. This is ordinarily preferable since it wiU result in minimum cost for optimum fl~w characteristics. It wi~l be understood, however, that the diameter of the flue may be uniform without departing f~om the spirit of the invention.
Refen~ing now to Figures 4, 5, and 6 there is shown a second embodiment of the apparatus in accordance with the invention in which a f~replace housing 40 is provided with a flue and damper a~sembly 42 which incllldes an inner flue 44 which extends up the primary flue (not shown) to the upper axial extremity thereoI. The assembly 42 includes a housing 46 through which the inner flue 44 extends. The housing 46 is disposed in fluid communication with the primary flue (not shown). Two dampers 48 are a part of the assembly 42 and are carried on gener~lly par~ Lel shafts 50, 50 which extend proximate to opposed sides 52, 52. The mounting between the acsembly 42 and the shafts 50, 50 allows rotational movement of the ~haf~s 50, 50.
Handles 54, 54 are respectively attached to the shafts 50, 50 and permit the manual rotation of the dampers 48, 48. In the illustrated embodiment the damper;3 48 each are generally rectanguLar with a rectangular opening therein.

The rectangular opening of one da m per 48 and the other da m per 48 are disposed in a~igned reLatlonship so that, as best seen in Figure 7, a generally square opening is def9ned at the inter~ace between the damper~ 48, 48 and which has a geometric center thereof disposed on the axis of the inner flLIe 44.
Inthisembodimentoftheinventiontheinnerflue 44 may have eithera 320~3 genera~ly squar~ cro~cs section throughout the axLal extent thereof, as be~ seen in Figure 4, or may have a generally square cross section which tapers Into a general3y cylindrical inner flue member 44a, as best seen in Figures 6 and 7.
The inner flue 44 in the embodiment iUuskrated in Figures 4-7 will be open at aLl timestotheupperatmosphere. Thecontroloftheflowofexhaustgasesfroma fit~ within the fïreplace a~ssembly 40 or other stove (not shown) wi~l be by means of the handles 54 which will rotate the shafts 50, 50 to position the dampers 48, 48 in the position illustrated in Figure 7. For example, with the da mpers 48, 48 fWly closed all of the exhaust gases will be directed out of the inner flue 44a.
In all e mbodim ents of the invenkion the da mper 16 will be divided in two halves and wi~l have a "central bore" when the halves ara coplanar. The "centr~ bore" will have a diameter as large as or larger than the inner flue diameter. The size of the inner flue will be selected based on the capacity of the fireplace cr stove with which it is associated.
It wi~l be seen that the proble m of very low flow of co m bu~tion gases in a r~atively ~rge flue duct has been e~iminated by the structure described hereîn~ More specifically the problem of a conventional damper being barely open d~ng long term operation of a wood stove with the associated build up of creo~ote and the ~ike e]iminated. It will be f~rther seen that the apparatus in accordance with the invention is simple to instaU in existing flues. In other forms of the invention an entire assembly including the outer flue may be installed particu~rly in new construction.

Claims (7)

Having thus described my invention I claim:

1. A damper assembly for cooperation with an associated flue:
an inner flue extending along substantially the entire axial extent of the associated flue, said inner flue defining first and second parallel flow paths which are respectively inside of and outside of said inner flue;
means for modulating the flow through said second flow path;
means for mounting said inner flue in generally coaxial relationship with the axis of the associated flue, said means for modulating comprises a pair of generally planar members; and said generally planar members are each pivotally mounted.

2. The apparatus as described in Claim 1, wherein:
said inner flue has a generally rectangular cross-section.

3. The apparatus as described in Claim 2, wherein:
said generally planar members are each coupled to handle members to facilitate pivotal motion of said generally planar members.

4. A damper assembly for cooperation with an associated flue:
an inner flue extending along substantially the entire axial extent of the associated flue, said inner flue defining first and second parallel flow paths which are respectively inside of and outside of said inner flue;
means for modulating the flow through said secibd flow path;
means for mounting said inner flue in generally coaxial relationship with the axis of the associated flue; and said means for modulating comprises a pair of generally planar members.

5. A damper assembly for cooperation with an associated flue:
an inner flue extending along substantially the entire axial extent of the associated flue, said inner flue defining first and second parallel flow paths which are respectively inside of and outside of said inner flue;
means for modulating the flow through said second flow path;
said means for modulating comprises a pair of generally planar members; and said generally planar members are each pivotally mounted.

6. The apparatus as described in Claim 5, wherein:
said inner flue has a generally rectangular cross-section.

7. The apparatus as described in Claim 6, wherein:
said generally planar members are each coupled to handle members to facilitate pivotal motion of said generally planar members.