Патент USA US2130133код для вставки
Sept. 13, 1938. J, Q, HOUSE FURNACE CONTROL DEVICE Filed Oct. _24, 1934 2,130,133 I 2 Sheets-Sheet l INVENTOR BY A.» ’” ATTORNEYS. Sept. 13, 1938. _ J. Q. HOUSE _' \ 2,130,133 FURNACE CONTROL DEVICE Filed Oct. 24, 1954 ~ 2 Sheets-Sheet 2 INVENTOR. , 949 a. 14M, 47.‘- % “,4 94M QATTORNEYJ. Patented Sept. 13, 1938 2,130,133 UNITED STATES PATENT OFFlCE 2,130,133 FURNACE CONTROL DEVICE John Q. House, Cleveland, Ohio, assignor to John H. Leonard, Cleveland, Ohio, trustee Application October 24, 1934, Serial No. 749,705 (01. 236-46) This invention relates to a damper control which, in the present invention, is kept closed 11 Claims. mechanism for furnaces and the like, a principal object being to maintain uniform rates of com bustion of predetermined intensities. _ An equally important object is to modulate and control the admission of air into and the dis charge of products from the combustion chamber in a manner such that the heat produced is e?iciently applied, overheating of the furnace 1 eliminated, and stack losses of combustible mat ter and heat are greatly reduced. Another object is to prevent over checking and consequent extinguishment of the ?re. A more speci?c object is to provide a simple and durable apparatus for controlling the operation of the furnace, which apparatus has a minimum number of working parts, may be installed readi ly without material or expensive changes in the furnace structure, and which operates to main i-e tain a rate of combustion commensurate with the amount of heat required and rate of transfer and convection of the heat from the furnace. Other objects and advantages will become ap parent from the following speci?cation wherein reference is made to the drawings, in which , Fig. 1 is a diagrammatic side elevation of a furnace showing an exemplary installation of the vided. , It is well known that in the usual furnace, if operating with the check damper D closed and the inlet damper I open, the rate of combus tion of the fuel will increase rapidly until the exhaust ?ue F and the stack S are unduly heat ed, due both to the direct escape of heated prod ucts from the combustion chamber and to the combustion in the ?ue and stack of volatile gases carried thereinto. After a predetermined. high temperature of the combustion chamber is reached, air cannot pass through the jacket J around the combustion chamber rapidly enough to absorb the heat as rapidly as it is being pro-. duced. Consequently, a large percentage of the heat is lost, the furnace and ?ue are overheated, and the discharge of heated air into the room does not increase in an efficient ratio to the in tensity of the heat of the furnace. In order to control the furnace so as to over come these disadvantages and to check the ?re ' when the ?ue gases have reached atemperature at which radiation of heat from the radiating Fig. 2 is a top plan view of a damper mecha hood and combustion chamber of the furnace is efficient in relation both to the passage of air nism embodying the present invention, the check thereabout and to the temperature requirements damper being partially broken away for clear of the rooms to be heated, the control mecha nism of the present invention is provided. present invention; ness in illustration; Fig. 3 is a vertical sectional View of the con trol damper and operating 'mechanism and is 35 taken on a plane indicated by line 3—3 on Fig. 1; Figs. 4 and 5 are sectional views taken on planes indicated by the lines 4—4 and 5-5 re spectively of Fig. 2; and Fig. 6 is a diagrammatic illustration of the 40 electrical circuits and vapor motor which may be used in connection with the damper mechanism, the vapor motor being shown in section for clear ness in illustration. ‘ Referring to Figs. 2 to 5 inclusive, the control mechanism comprises a butter?y ?ue damper Ill having a central bleeder vent I l and mounted on a radially protruding shaft l2. The damper H] is preferably of such size that, when turned to dispose the plane of its surface transversely of the ?ue F or portion of the stack in which dis posed, it substantially ?lls the ?ue and blocks the same except for the vent II and leakage around its margins. The shaft I2 is rotatably mounted in the wall of the ?ue F and protrudes For the purposes of illustration, the invention outwardly therefrom. Adjustably secured on the is shown in connection with a generally used type of household hot air furnace, its ‘use with other outwardly protruding end of the shaft I2 is a yoke having arms I3a and I32), which prefer ably extend horizontally and are disposed gen erally in a plane through the axis of the shaft types of fuel burning equipment being readily apparent therefrom. Referring ?rst to Fig. 1, the furnace comprises 50, a combustion ‘chamber C, enclosed in the usual air jacket J, and having a discharge ?ue F which communicates with a suitable stack S, the stack forming a continuation and part of the ?ue F and the extending portion F’ of the ?ue being pro 55 at all times. An adjustable inlet damper I for controlling the admission of air to' the combus tion chamber through the ash door is also pro vided with the usual adjustable check damper D I2 and 45° to the plane of the damper l0. , Mounted on the ?ue F is a housing M in which is rotatably mounted a horizontal shaft l5, which extends parallel to the ?ue F. The housing I4 is disposed between the damper l8 and stack S, the end of the shaft l4 nearest the damper pro truding through the end wall of the housing. The 2 2,130,133 protruding end of the shaft I5 is provided with a tongue |6 disposed at 90° to the shaft axis and extending between the arms |3a and I3!) of the yoke. Thus rotation of the shaft |5 through about 90° swings the damper ID to open and closed positions. For adjustment, the tongue may be secured on the shaft |5 by a collar |6a and set screw |6b. Secured by one end to the shaft l5, within the housing I4, is a thermostatic bi metal coil I1. In one end wall of the housing I4 is a vertical slot |8 through which an anchor lug l9 pro-_ trudes so that it may be moved along the slot from outside the housing. The lug is provided 15 with a bolt |9a which is engaged by a wing nut IS?) on the outside of the housing for securing the lug in different adjusted positions. The opposite end of the thermostatic coil I1 is ?xedly secured to the anchor lug 19. Thus, if the lug is held in 20 a given ?xed position, the coil |‘|, upon heating and cooling, will rotate the damper toward closed and open positions respectively. The ei?ciency of convection, the ratio of flue temperatures to hood temperatures, and the rates 25 of combustion desired vary for different furnaces and under different conditions to be met. Con sequently it is desirable to adjust the tension on the coil |'| so that it will operate the damper to fully closed and open position within different 30 temperature ranges consistent with such extra neous conditions. This adjustment of the coil I1 is effected by moving the anchor lug up or down, as the case may be, and securing it in the desired position. The portion of the housing M which accom modates the coil I1 is preferably partitioned off from the remainder by the partition wall 20a and 20b‘ and the bottom wall 2| of this portion is concave upwardly and deeper than the re mainder of the housing so that, when the hous ing rests upon the ?ue F, the coil accommodat ing portion protrudes into the flue and is ren dered more quickly responsive to the tempera ture therein. The remainder of the bottom wall 45 of the housing | 4 may be shaped to conform to the shape of the ?ue on which installed. The bottom wall of the largest portion of the hous ing |4, between the partition wall 20a and the opposite end, is provided with an opening 22, a 50 coextensive opening being provided in the ?ue F 35 nace. For this. purpose, an electrically respon sive motor is provided, an electrically heated vapor motor such as indicated at 25 in Figs. 1 and 6 being preferable. The shaft l5 extends through the partition wall 201) of the housing I4 and protrudes into the supplemental portion 26 of the housing. On the protruding end of the shaft I5 is a cam 21 which may be secured in different rotated posi tions relative to the shaft l2 by means of a set screw 28, the operating faces of the cam being covered with insulating material and forming op erating abutments for a suitable high and low limit switch mechanism. The switch mecha nism, in turn, comprises a high limit spring lever 29 and a low limit lever 30, secured to the wall 201) and suitably insulated therefrom. Each is provided near. one end with electrical con tactor 29a, and 300, respectively, and both are of electrical conducting material. A common com plementary contact element 3| is provided and comprises a block of electrical conducting ma terial which is secured in ?xed position on the wall 2% and is insulated therefrom, and car ries a contactor 3|a. The levers 29 and 30 are so positioned that in certain rotated positions of the shaft I5, the cam 21 engages them and swings them to break contact, and in other ro tatedv positions, disengages them so that they spring back and return the contactors to effect 30 engagement of the contactors 29a and 30a with the common contactor 3|a. The thermostatic coil is preferably arranged relative to the damper It) so that, at normal room temperatures or a few degrees thereabove, the damper will remain fully open. Upon heating, the coil |1 rotates the damper shaft |5 to close the damper Ill. The cam 21 is usually adjusted so that when the damper I0 is in closed position, the contact between the contactors 29a, 30a, and , 3|a will be broken as shown in Fig. 4. In order that normal tension on the coil I‘! may be changed by» positioning the anchor lug IS with out causing it to move the damper l0 beyond its fully closed position when heated, a suitable stop 32 is provided. Upon cooling of the coil H, the cam 2‘! is rotated counter-clockwise. The‘ longest operating face of the cam 21 operates the low limit control lever 30 and the shorter face, the lever 29, for purposes later to be described. so that air may pass through the housing to the Referring particularly to Fig. 6, the levers 29 ?ue to check the draft. As stated above, the usual check damper D is kept closed at all times. damper 23 which swings upwardly for opening and 30 are connected, through the lead wires 33 and 34 each in separate electrical series with an electric heating element 35, and a step down transformer 36, the common contactor 3|a com the passage through the housing and which may pleting both circuits._ The circuits, so described, return by gravity to closed position. are preferably of low voltage, the same being energized by the usual 110 volt alternating cur rent household circuit through the medium of the transformer 36. 60 The heating element 35 is utilized to operate the vapor motor 25, such as diagrammatically illustrated in Fig. 6, which motor is utilized to operate the check damper 23 and inlet damper I. Generally, this motor consists of a closed cy lindrical compartment in which is provided a reciprocal piston 38. The lower end of the com partment is contracted as indicated at 39, the contracted portion containing a suitable highly expansive liquid or ?uid which, when heated by 70 the element 35, will operate the piston in one direction. A return spring 40 is provided for Mounted on top of the housing I4 is a check The coil I1 is such that as its temperature is increased, it rotates the shaft l5 to swing the 60 ?ue damper ID to closed position, shown in Figs. 3 and 5. It is desirable that the check damper be gradually opened as the damper l0 closes and vice versa. To accomplish this result, a lever 24 is rigidly secured on the shaft I5 in position 65 to engage the underside of the damper 23 and lift the same as the shaft rotates. The relation between the operation of the dampers I0 and 23 with respect to each other and with respect to the coil |'| may be varied by bending the lever 24 to different adjusted positions as well as by shift ing the position of the’collar |6a on the shaft l5. In most instances, however, it is desirable to supplement the mechanical operation of the flue damper ID by electrical operation of the check 75 damper 23 and of the inlet damper I of the fur returning the piston in the opposite direction. The piston, in turn, is connected to a lever 4| which carries an operating lever 42. One end 3 2,130,133 of the operating lever 42 is connected through the medium of a chain 43 and suitably arranged pulleys to the check damper 23, and the other end of the lever 42 is similarly connected to the inlet damper I. When the lever is moved to the position indicated in Fig. 1, the inlet damper I is closed and the check damper 23 opened and when the lever is rotated to dispose vit in the reverse position, the check damper will be moved 10 to closed position and the inlet damper I to open position. The piston is so connected to the lever 4| that it moves the lever 42' to position to open the inlet damper I and close the check damper 23 consequent upon heating of the ?uid the passage ll. Meanwhile the low limit switch has been opened. In the usual furnace, air will not pass through the jacket fast enough to absorb heat ‘e?iciently beyond a furnace temperature of about 300° con sequently a rate of combustion which increases the temperature unduly beyond 300-0v dispropor tionately increases the stack losses. However, as this temperature is approached the damper i0 is closed gradually so as to reduce the increase in 10 rate of combustion and, in fact, maintain a sub stantially constant rate by reducing the effec tive stack pull, bailling the heated gases and also volatile matter from escape through the ?ue or 15 and closes the damper I and opens the check stack and retaining them longer in the combus damper I upon cooling of the ?uid. Thus any failure in the electrical power supply will imme diately check the furnace and eliminate ?re hazards due to overheating. 20 Instead of the vapor driven motor, however, any of the well known types of electrical motors tion chamber. commonly used for opening and closing dampers may be utilized, the circuit thereto being varied to meet the requirements of the particular motor, 25 all in a well known manner. For most conditions, the normal setting of the thermostatic coil IT is such that it will close'the damper Ill upon reaching the stack temperature of 400° to 450° Fahrenheit. 30 Since it is generally desirable to control the furnace partially in response to room tempera tures, a thermostat 45, described herein as located in the room to beheated, though it may be re sponsive to heat elsewhere, is provided. The thermostat 45 is of the type to make contact when cool and break vcontact when heated and is connected in series in circuit with the high temperature limit lever 29. Therefore, assuming both the room to ‘be 40 heated and the furnace are cool and the fire‘ is started, the room thermostat, being cooled below its set minimum temperature is in position to close the circuit therethrough. The cam 21 is disposed about horizontally and both electrical circuits to the motor through the contactors 29a, 30a and cm are closed and energized. The damper ID is fully open as also is the inlet damper I, the check damper 23 being closed. In this position the entire stack pull is effective for increasing ‘ ' When the rate of combustion increases too rapidly an over run in the ?ue temperature re sults. Likewise a steady, though slower, increase in combustion might continue even with > the 20 damper l0 closed. However, when the damper ID has moved to the fully closed position, the abutment cam’ 21 has engaged the lever 29 and moved it so as to break the contact between the contac‘tors 29a and 3m. This operation renders the coil 35 inoperable by both limit circuits where upon the motor operates in the reverse direction to lower the damper I and openv the check damper 23 thus reducing the intensity of combustion to a degree to which the heat can pass from the 30 furnace. Upon starting a fresh ?re these operations may be repeated several times until the surge in the increase or decrease of combustion is gradually reduced and a comparatively steady ?re at the required rate for e?icient radiation is obtained. In this condition the furnace comes primarily under the control of the damper I0 which modu lates the rate of increase and decrease to a sub stantially uniform rate of combustion at the in 40 tensity for which the damper ID has been set. However, complete checking for a long period may extinguish the ?re, especially on a warm day on which the room thermostat would never close the high limit circuit. However, the cam 45 21 remains in operative engagement with the lever 30 breaking its contact until a much lower temperature of the coil I1 is reached, for example, a stack temperature of 200° Fahrenheit. At this lower temperature, the low limit circuit is ener 50 to maintain this relation while energized._ ‘If, gized to close the check damper 23 and open the while this condition exists, the room reaches the inlet damper so as to sustain combustion at a the rate of combustion. The motor continues required temperature, the thermostat 45 breaks the circuit and the motor operates to close the inlet damper I and open the check damper 23‘ unless the low limit switch is closed. Usually, however, the heating of the room lags behind the heating at the furnace and before the room thermostat breaks contact, the damper It) be CO comes eifective. Thus with the damper I' open and check damper 23 closed, the entire stack draft is effective and increases as therate of combustion increases. This causes an increase in the temperature of the ?ue gases and the 65 products passing around the housing l4 and re sults in heating the coil l1. As the coil I‘! be comes heated, the damper ID is gradually moved toward closed position, thus reducing the stack pull that is effective in the combustion chamber of the furnace and retaining the gases therein, su?icient air bleeding in through the fuel bed to maintain combustion of the so retained gases. The lighter products of combustion, however, are bled out aroundv the damper H] and vthrough lower rate. _ The motor 25 is preferably comparatively slow in operation so that too rapid changes in the 55 operation of the furnace are eliminated. For purposes of illustration, the damper l0 and operating mechanism have been shown as in stalled in the stack portion F near the combustion chamber so as to be more quickly affected by 60 changes in the chamber. The structure may, however, be placed directly in the upright or other portion of the stack. > ' Usually the lever 24 permits closing of the 65 check damper 23_ before and effects opening thereof after the temperatures at 'whichthe check will be operated by the motor 25, so it does not interfere with motor'operation but supplements it. If many instance, the setting of the high 70, and low limits is such that the lever 24 interferes with the motor operation, the lever 24 may be removed or bent out of place. The contactors 29a and 30a, as well as those of the room ther mostat are preferably of the adjustable gap type 75 4 2,130,133 so that substantially any desired range of high and low limits may be obtained. It is apparent from the foregoing description that a simple and effective apparatus for the purposes recited is provided, and changes in the structure shown may readily be made without departing from the broad features of the inven tion. , V - I claim: 10 I 1. In a fuel burning apparatus having a com bustion chamber, an exhaust ?ue leading there from, an inlet air-control damper and a check damper, a ?ue damper disposed withinsaid ?ue and movable to different positions to vary the 15 effective size of the ?ue passage, thermostatic means responsive to heat of the products in saidv ?ue and operably connected to the ?ue damper for moving the same to said different positions, an electrically operable motor means drivingly connected to one of said ?rst named dampers for moving the same to predetermined positions, an electric circuit connected to said motor means and to a'source’ of electrical power, and means operable by said thermostatic means for energiz 25; ing and unenergizing said circuit whereby the ?ue damper and one of said other dampers are op erated in given relations to each other by the the effective‘ size of. the ?ue passage, thermostatic means responsive to heat produced by the appa ratus operably connected to the ?ue damper for moving the same to said different positions, an electric circuit, electric motor means electrically connected in said circuit and operably connected to the inlet damper for opening the said damper consequent upon energization of said circuit, a switch in said circuit, and means operable conse quent upon movement of said ?ue damper to position restricting the ?ue passage to open said switch for breaking the circuit therethrough, whereby the inlet damper may be closed. 5. In a fuel burning apparatus having a com bustion chamber, an exhaust ?ue leading there from, and a check damper, a ?ue damper dis posed within said ?ue and movable to different positions for varying the effective size of the ?ue passage, thermostatic means responsive to heat of the products in said ?ue and operably con 20 nected to the ?ue damper for moving the same to said different positions, an electric circuit, elec tric motor means electrically connected in said circuit and operably connected to the check damper for closing the same consequent upon 25 energization of said circuit, a switch in said cir cuit, and means operable to move said ?ue thermostatic means and motor means respec damper to position restricting the ?ue passage tively. and operative to open the switch and break the circuit therethrough when said means is operated 30 to effect said movement of the ?ue damper, whereby the check damper may be opened, and 2. In a fuel burning apparatus having a com bustion chamber, an exhaust ?ue leading there from, an inlet air control dampervand a check damper, a ?ue damper disposed within said ?ue means operable consequent upon breaking the and movable to different positions for varying the effective size of the ?ue passage, thermostatic means responsive to heat of the products in said ?ue and operably connected to the ?ue damper for moving the same to said different positions, an electrically ‘operable motor means drivingly said circuit to open the check damper. 6. In a control mechanism for a furnace hav 35 ing a combustion chamber, an exhaust ?ue lead ing therefrom, an air inlet control damper and a check damper, a ?ue damper disposed within said ?ue and movable to different positions, elec 40. connected to one of said ?rst named dampers for moving the same to different positions, an electric circuit connected to said motor and to a source of electrical power, abutment means movable by said thermostatic means concurrently with the ?ue damper, an electric switch in said circuit, and an operating lever thereon movable to dif ferent positions tomake and break said circuit, said lever being disposed in the path of travel of said abutment means and movable thereby to predetermined positions for effecting operation of the damper associated with said motor means. 3. In a fuel burning apparatus having a com bustion chamber, an exhaust ?ue leading there from, an inlet air control damper and a check damper, a ?ue damper operatively associated 55 with the ?ue and movable to different positions trical-1y operable, means operable when energized for operating the» first mentioned dampers to given positions, an electric circuit connected to said means, a switch in said circuit, a thermo static lever drivingly connected to. said ?ue damper for moving the same to different posi tions in response to temperature changes affect ing said thermostatic lever, means operable by the said thermostatic lever for opening said switch, and means for returning said switch to closed position, whereby said dampers may be operated in predetermined relations to each other. . Y a 7. In a fuel'burning apparatus having a com bustion chamber, an exhaust ?ue leading there from, an inlet air control damper, and a check 55 damper, a ?ue damper disposed within said ?ue for varying the operation of the combustion chamber, thermostatic means responsive to heat and movable to different positions for varying the effective size of the ?ue passage, thermo of the products in said ?ue and operably con static means responsive to heat from said appa ratus for operating said ?ue damper, a, motor operable to open the inlet damper and close the check damper when operating in one direction and operable to close the inlet damper and open the check damper when moved in the opposite direction, an electric circuit connected to said 65 motor, a switch in said circuit, said circuit, when 60 nected to the ?ue damper for moving the same to said different positions, an electric circuit, electric motor means electrically connected in said circuit and operably connected to thev inlet damper for opening the said inlet damper con sequent upon energization of said circuit, a switch in said circuit, and means operable con-1 sequent ‘upon movement of said ?ue damper to a predetermined position to open said switch for breaking the circuit therethrough, ‘whereby the 70 inlet damper may be closed. ' ' 4. In a fuel burning apparatus having a com-i bustion chamber, an exhaust ?ue leading there from, an inlet air control damper and a check entirely closed effecting operation of the motor to open the inlet damper and close the check damper, means operable by said thermostatic means for opening said switch, and means oper~ 70 able consequent upon opening said switch to operate said motor in the opposite direction. damper, a ?ue damper disposed within said ?ue 8. In a control mechanism for a furnace hav ing a combustion chamber and an exhaust ?ue and movable to different positions for varying, leading'therefrom, a check damper, a ?ue damper 75 5 2,130,133 disposed within said ?ue and movable to different positions, a thermostatic lever drivingly con nected to said ?ue damper for moving the same to di?erent positions in response to temperature changes a?ecting said thermostatic lever, means operated by said thermostatic lever and drivingly connected to the check damper for operating the check damper concurrently with the operation of the ?ue damper, whereby said dampers may 10 be operated in predetermined relations to each other. 9. The combination with a fuel burning appa ratus having a combustion chamber, an exhaust ?ue leading therefrom, a check damper and a 15 ?ue damper disposed within said ?ue and mov able to different positions for varying the effec tive size of the ?ue passage, of thermostatic means directly responsive to heat from said ?ue and operable to move both said ?ue damper and and for opening the same when both circuits are open, a high limit switch‘ in one of said circuits, a low limit switch in the other circuit, means operable consequent upon movement of said ?ue damper to position greatly restricting the ?ue in the high limit circuit for making and break ing the high limit circuit independently of said high limit switch, and means operable conse 11. In a fuel burning apparatus comprising a 15 combustion chamber, an exhaust ?ue leading therefrom and a stack leading from said exhaust ?ue, a housing mounted on said exhaust ?ue be tween the combustion chamber and stack, said exhaust ?ue and housing having aligned openings in inverse relation to each other. 10. In a fuel burning apparatus having a com bustion chamber, an exhaust ?ue leading there from, and a check damper, a ?ue damper dis 25 posed within said ?ue and movable to di?erent positions for varying the e?ective size of the ?ue passage, thermostatic means responsive to heat communicating the interior of the ?ue and hous ing at a point between the combustion chamber and stack, said housing having an opening for admitting outside atmosphere therethrough into the ?ue, a check damper carried by the housing 25 and cooperating with said last mentioned pas sage, a ?ue damper in said ?ue between the housing and combustion chamber, thermostatic including an electric motor means electrically lever means carried by said housing in heat ex changing relation with said ?ue, and means oper ated by said thermostatic lever means for con connected in said circuits and operably connected trolling said dampers. to the check damper for closing the same conse quent upon energization of either of said circuits 10 quent upon movement of said ?ue damper to less restricting position to close the high limit switch and to a still less restricting position to close the low limit switch. said check damper to open and closed positions produced by the apparatus and operably con nected to the ?ue damper for moving the same to said different positions, electric circuits, means 5 passage to open both said switches and break the circuits therethrough, thermostatic switch means JOHN Q. HOUSE.