US2324010A - Heater - Google Patents

Description

July 13, 1943 c. E. MEYERHOEFER ET AL 2,324,010

HEATER Filed Feb. lO, 1940 `.E5 Sheets-Sheet l mlm ATTORNEY 5 Sheets-Sheei 2 NVENTORS m w am W m ATTORNEY C. E. MEYERHOEFER ET AL HEATER Filed Feb. l0, 1940 July 13, 1943.

.. .July 13, E. MEYERHoEFi-:R EriAl-f. A; i

HEATER Filed Feb. lO, 1940 5 vShf-,ets*Sheet 5 L@ s S n@ 'w S i I' lSi@ 1, Ww MHH N M JLU w WD l MKMM sw? ATTORNEY C. E. MEYERHOEFER ET AL. 2,324,010

HEATER July 13, 1943.

Filed Feb. lO 1940 5 Sheets-Sheet 4 INVENTORS mwm A ATTORNEY July 13, 1943- c. E. MEYERHOEFR E11 AL 3M-wm HEATER Filed Feb. 10, 1940 5 Sheets-ShearJ 5 HOT-4 (00L/N6 51,7 n I MIT l:

Jaw/v H. www" INVENTGFCS ATTORN EY Patented July 13, 1943 UNITED STATES PATENT. OFFICE HEATER Carl E. Meyerhcefer, Brooklyn, and William C. Ballard, Jr., Ithaca, N. Y., and Johnl H. Smoot, Darien, Conn., assignors to E. A. Laboratories, Inc., Brooklyn, N. Y., a corporation of New I York Application February 10, 1940, Serial No. 318,256

1 Claim.

nominal figure and which will operate over long' periods of time with freedom from all diiiiculties.

A further object is that of constructing an apparatus of this type and in which, if combustion is interrupted, such combustion will be rapidly reinitiated without the user ordinarily becoming aware of such interruption.

Another object is that of furnishing a heater which will maintain in inoperative condition all of the fluid-the temperature of which is being raised-until the parts have reached a temperature such that it is desirable to distribute such uid.

Still another object is that of furnishing an extremely effective safety factor which will function forthwith upon a dangerous condition arising.

An additional object is that of combining with a heater an air distributor of extremely desirable design and which will be ideally suited for the dispersion of warmed air throughout confined spaces, such as the interior of the vehicle.

With these and other objects in mind, reference is had to the attached sheets of drawings, illustrating practical embodiments of the invention and in which:

Fig. l is a somewhat diagrammatic perspective view of the exteriorof the heating apparatus;

Fig. 2 is a sectional side view taken through the main portion i the unit;

Fig. 3 is a sectional plan view taken along the lines 3 3 and in the direction of the arrows as indicated in Fig. 2;

Fig. 4 is a transverse sectional view taken along the lines 4-4 and in the direction of the arrows as also indicated in Fig. 2;

Fig. 5 is a sectional plan View of the unit'as shown in the preceding figures;

Fig. 6 i; a perspective View of the several eleproper;

Fig. 7 is a partly sectional end View taken along -ments which provide the combustion chamber the line 'l--l and in the directionof the arrows as indicated in Fig. 2;

Fig. 8 is a similar sectional view in enlarged scale and taken along the line 8-8 and in the direction of the arrows, as indicated in Fig. 2;

Fig. 9 is a fragmentary sectional side view taken along the line 9-9 and in the direction of the arrows as indicated in Fig. 1;

Fig. 10 is a sectional bottom plan view taken ralong the line lll- I0 and in thedirection of the arrows, as indicated in Fig. 7;

Fig. 11 is a transverse sectional view taken along the line ll-ll and in'the'direction of the arrows, as indicated in Fig. 7;

Fig. 12 is a fragmentary, partly sectional, side` view of an alternative form of construction which may be employed;

Fig. 13 is a diagrammatic view of one form of circuit which may be embodied in the heater assembly;

Fig. 14 is a partly fragmentary sectional front view of the air distributing unit which is preferably associated with the heater proper;

Fig. 15 is a transverse sectional View taken along the line I5'-|5 and in the direction of the arrows, as indicated by Fig. 14;

Figs. 16 to 20 inclusive show somewhat diagrammatically the sequence of operative steps followed by the thermostat, and

Fig. 21 is a, diagrammatic view showing an alternative view of the thermostatic control for both the ignitor and motor.

As afore brought out, it is proposed, by means of the present invention, to provide a heater which may be employed in numerous diiferent associations, but which will be of primary value when utilized in conjunctionl with an internal combustion inotor, and especially in association with automobiles. The inventionhas been ac cordingly illustrated in its preferred association. This, however, is to be taken in an illustrative rather than in a limited sense, excepting where, from a reading of the'claims, the contrary is obvious.

tThus, referring primarily to Fig. 1, the numeral `25 indicatesthe dash of a vehicle and forward of which a motor block 26 is positioned. Associated with the motor, in accordance with conventional construction, is a manifold assembly 21 coupled to a carburetor 28, to which a fuel line 29 is connected. At a point short` of the carburetor, a fitting 30 may be mounted to supply fuel through a, line 3l. Likewise, the in take manifold 21 may have associated with it a tting 32 from which tubes 33 and 34 extend;

the latter being the more or less conventional tube coupled to the motor of the windshield wiper.

The line or tube 3| has its inner end connected to a casing 35, defining a float chamber which may be supported by a housing 36, secured to the face of the dash. Extending from the upper edge of the housing is a conduit 31, having its inner end projecting through a collar 38 which defines an opening in the dash. A second conduit 39 may conveniently extend from the lower end of housing 36 throughan opening in the dash, it being thus obvious that air to the rear of the dash may flow through conduit 31, housing 36 and hence through conduit 39. Additionally, extending through the dash, is a control member which, as shown, may include a rod or wire 40 of flexible material, conveniently housed within a sheath 4|. Secured to the inner end of the exible rod or wire 40, and, for example, within the passenger compartment of the vehicle, is a knob or other suitable control device (not shown) which assembly serves to permit of projection and retraction of element 40 within the sheath..

Mounted upon the opposite` side of the dash 25 is an air distributing device which may take numerous different forms, but which conveniently embraces a structure which has the functional characteristics of those illustrated in Figs. 14 and l5. In these views, the numeral 42 indicates a casing within which a motor 43 is disposed. The motor has extending from it control leads (not shown) conventionally connected to an electrical source and a circuit breaker. A fan 44 of the axial type is mounted by the motor shaft, and the inner end of casing 42 is formed with an opening defined by a collar 45 to which is coupled the hose or conduit 39.

The front face of the casing is open, and mounted within the same is a ring or band 46 to which may be coupled an actuating element 41 which permits of this element being rotated or swung with respect to the casing. The band also mounts a plurality of deflectors or Vanes 48, by means of pivot pins 49, and handles or knobs 50 may be provided so that the panels may be swung around their a'xes and maintained in any desired position.

It follows as a consequence of this construction that with the motor 43 operating, air will be drawn into the casing 42 through collar 45 and this air will be blown rearwardly, or to the left, as viewed in Fig. 15, and out between the edges of the adjacent panels 48. The latter may be swung as a group so that the air, thus distributed, may, if desired, be diverted at tangents to the axis of the motor shaft. To prevent any vortex action being set up, a radial series of plates may be secured to the inner face of casing 42 and extend inwardly to a point adjacent the motor case 43, it being apparent that by this construction, not alone is the foregoing objection overcome, but also air will be flowing in contact with and over the motor casing.

An opening may be formed in the side wall of casing 42 and a fitting 52 may be coupled in line with this opening. This fitting may be furnished with an opening, a flow of air through which may be controlled by a valve 53 mounted on a shaft 54. Thus, if valve 53 is moved upwardly, as viewed in Fig. 14, to an extreme position, any air which tends to flow through fitting 52 will be blown outwardly and downwardly through the opening in the fitting 52. If the unit-as is customary-is secured to the dash to the right of the drivers seat, such air flow will be directed towards the drivers feet. With valve 53 partially closed, a certain amount of airwill be thus deected, and the balance of the same will fiow upwardly through the fitting. With the valve in the position shown in Fig. 14, all air passing through this casing opening will flow through the fitting, and the latter may be coupled by conduits (not shown) to defrosting nozzles disposed adjacent the windshield, or to any other portion of the interior of the vehicle. It is obvious that with one or more of the panels 48 closed, an increasing amount of air will be dlverted through fitting 52 which is an extremely desirable factor under certain atmospheric conditions.

, Disposed within, or adjacent the housing 36, is a heat exchange element over which the air, distributed by the unit shown in Figs. 14 and 15, flows. This unit is illustrated to best advantage in Figs. 2 to 7 inclusive. In the first of these,

' it will be seen that the casing 35 is in the nature of a fioat chamber, within which, as shown in Fig. '1, a fioat 55 is disposed. This float is pivotally supported as at 56 by an arm 51. The latter bears against a stem 58 Which, as shown in Fig. l0, is preferably of irregular section. In view of the fact that the stem is encircled by a tube 59, or other element having a configuration dissimilar to that of the stem, passages are furnished through which fiuid may fio'w. The tube 59 is threaded into a correspondingly threaded fitting 60 which may form a part of the cover of the float chamber, and the base of the tube may conveniently be enlarged and spun over to provide a mounting and retaining portion for a guide plate 6|, which is apertured to receive the lower end of stem 58. The upper end of the tube may present a perforated base 62 which, in conjunction with a washer 63, presents a valve structure regulating the iiow of fluid through tube 59. The washer 63 may be formed of Thiokol, "neoprene, or any other material which resists the action of gasolene or other fuel employed in connection with the heater; it being apparent that when the oat has reached a sufficiently raised position, further in-flow through the fitting 64 is prevented. This fitting is coupled to line 3|, as shown in Fig. l.

It will finally be observed, With reference to this unit, that it may be mounted upon a bracket 65 secured to housing 36, and that the upper end of the cover may be formed 'with a vent opening 66. Moreover, a discharge tube 61 may extend into the oat chamber and have its lower end reduced, or fitted with an element to provide a metering plug 68, while the base portion of housing 36 may be formed or have several surge preventing bafiles 69 extending upwardly therefrom.

The upper end of tube 61 is coupled to a fitting 10 from which a tube 1| extends to a carburetor assembly. The latter may include a nozzle element 12 mounted upon the upper end of tube 1| by means of la packing nut assembly 13. The nozzle is formed with a series of inwardly and upwardly extending grooves providing air passages and., moreover, hasits body threaded to maintain in association therewith a Venturi element 14. The most constricted bore portion of the latter lies preferably adjacent the upper end of the nozzle and it will thus be seen that the in-rush of air through passages 15 Wil1 serve to create a suction adjacent the upper end of the nozzle, such that a combustible mixture is formed at this point. l To assure a thorough comingllng and even dispersion of the fuel particles throughout 'the air vehicle,it is preferred that member 14 at a point beyond its zone of maximum constriction, be formed with a radially ex tending passage 16. Assuming suction to be exerted on the upper end of the Venturi element, it is apparent that airwill be drawn through this passage in a directionperpendicular to the path of flow of the combustible mixture. In this manner, the desired results are achieved.

Immediately beyond the carburetor assembly a control valve is disposed. The structure embraced in this unit may include a tubular member 11 formed with a seat portion 18, into contact with which a valve body 19 may be projected. This valve body is tapered in a direction towards the seat, as indicated at 80, and terminates in a reduced end portion 8| .whicheven with the valve in fully retracted positionwill assure of a guiding cooperation between the valve and its seat. The valve body 19 is, moreover, of sulilcient length so that with the valve fully opened, it will lie adjacent or bear-against the end cap 82, which closes the outer end of tube 11, and is formed with an opening through which the stem 83 of the valve slidably extends. Consequently, wth the valve open, body 19 will be disposed in sealing relationship with respect to cap 82.

To secure a shifting of the valve from the position shown in Fig. 2 to a fully open position, a lever 94 may have one of its ends operatively coupled to stem 83, while its body is pivotally supported by a bracket 85. The latter may also mo'unt a snap type switch 86 having an operating arm 81 coupled to lever 84. The outer end of the lever may be connected to the rod or wire 40, as heretofore described.

It follows that with the Venturi member 14 coupled to tube 11, and the latter mounted by, for example, a nut 88, in clamping contact with casing 86, the entire assembly will be rigidly supported and maintained. Moreover, a movement of rod or wire 40 will result in a shifting of valve 19 from open to closed, or closed to open, positions. Additionally, such rocking of the lever will cause the switch 86 to be thrown to open and closed positions. latter, the lever will be automatically biased to one of two extreme positions so that there will be'no danger of the valve being only partially open or closed. Tube 11 extends into casing 36 and is coupled to a cylindrical member 89 delining a combustion chamber; Extending downwardly from the latter is a well member 90 within which is mounted an ignition coil or heating element 9| having one of its ends grounded, and its opposite end electrically connected to terminal 92,

Within the combustion chamber is an assem bly which has been best illustrated in Fig. 6. This assembly may include an outer plate 99 formed with arcuate slots 94 and a forwardly bulged or conical lportion 95 extending in the direction of the carburetor. This plate is preferably formed of stainless steel and to the rear of the same, a sleeve 96 is disposed which is formed with a slot 91 so that it may be readily introduced into member 89, and will tend to expand into intimate contact with the inner face of the same. Moreover, sleeve 96 is provided -with an opening 98, the diameter of which should preferably be slightly in excess of the diameter of the upwardly extending portion 99, or flange Due to the construction of the I of well member 90. Again to the rear of sleeve 96 there is disposed a plug |00 of ceramic material which may be conveniently formed with radially extending slots |0|, and a recessed face |02 extending towards the sleeve 96. The rear face of plug |00 may be outwardly bulged as indicated at |03 in Fig. 2. In addition to the functions hereinafter specified, in connection with plug |00, it is, at the present time, to be understood that this member acts as a flamearresting element preventing thevflame from existing to any material extent within the structure of the heat exchanger. Thus, to a certain extent, the plug may be regardedas an arresting element which will permit a ready. flow of the l products of combustion beyond the chamber within which it is disposed, while at 'the same time arresting a flow of theflame beyond such chamber, The rear end of member 89 is closed by a"cap |04 which has its inner face spaced from the rear face of plug |00 and preferably extending inl planes parallel to such rear face of the plug. Interposed betweencap |04.and the plug is a ring |05 which, as shown in Fig. 6, may b split and serve as a spacing or locking ring to maintain the relative position of the parts.

vDealing with this phase of the structuregit will be understood that with suction exerted beyond cap |04, the combustible mixture developed by the carburetor will-with valve body 19 openflow past and over the surfaces of plate 91 through openings v94 and so into the space defined by sleeve 96. Thence, fluid will flow through openings |0| and so through the .bore of the cap |04. Again assuming that the igniting coilv |0| is energized, it will be appreciated that by this ele'ment, or its functional equivalent, ignition of the mixture is initiated.

However, it has been found from practical experience that the matter of assuring combustion is not at all a simple or obvious one. More particularly, it will be appreciated that a heater of ths character wil1 ordinarily be applied in 4in stallations Where, when it is to be operated, its

parts will have an extremely low temperature. If, for example1 the' heater is mounted in an automobile housed in a'garage which has no heat, such temperatures may well be below zero. At the same time, 'it will be understood that with the heater operating for a lengthy period of time, the temperatures within -the combustion chambers will be very high.

Thus, quite aside from the question of desirability of fuel economy, one has tobe assured that Wi th completely chilled surfaces, combustion will be initiated while at the same time the mixture must not be' so rich that with the high operating temperatures, which will subsequently prevail, the ame will become self-extinguishing or intermittent in operation. In actual practice, and with a given size of heater, the fuel consumption will be as low as 1/2 pint of gasolene per hour and, thus, the difliculties of the problems which arise will be apparent.

Assuming that the heater is just being started, it will be appreciated that with the extremely low temperatures ofthe air which may be entering through passages 15, thus the low temperature of the parts, the fuel mixture produced by the carburetor will not be as perfect as might be desired. Now, when such mixture strikes the surface of plate 95 and sleeve 96, it is found that these parts will actually function as a condenser structure. Consequently, the amount of propi chamber',

erly diffused fuel particles which will now, under these circumstances, through the combustion are negligible. Certainly this flow would not be of a character such as to result in combustion of the mixture, especially having in mind that the carburetor parts are proportioned to supply a fuel mixture ideally suited to cause a functioning of the heater when it has actually reached an operating temperature. It must also be assumed that the ignition coil 9| will begin to function at the time that the flow of combustible mixture is initiated. However, this functioning will not immediately result in the coil reaching a temperature such that it could fire the gasolene. Rather a half a minute may elapse before the coil becomes incandescent. In the interim, the condenser action continues to exist. Consequently, the fuel particles will be deposited upon the surface of plate 93 and sleeve 9B and will naturally tend to flow along the lower surface of the latter, due to the continued inrush of air and the action of gravity.

It is particularly to be noted that .the well member 90 is preferably mounted to extend downwardly. Consequently; the fuel particles, in movlng over the surface of sleeve 96, will tend to be deposited in the well of member 90. In such location, it is apparent that the radial heat created by coil 9| will tend to vaporize these particles or droplets. Moreover, these fuel particles, being in immediate proximity to the coil, it follows that as the latter reaches an operating temperature they will be ignited. This will cause a low temperature name to result and this flame will usually be characterized by an orange color. It will be understood that before ignition has occurred, a certain amount of fuel particles, which have been thrown past the opening 98, will be deposited upon plug |00. In fact, the latter will quickly reach a saturated condition. Consequently, when the low temperature flame is created, it will propagate through the combustion chamber and the surface, andthe plug will likewise have a low temperature flame springing from its surface. This will quickly result in the temperture of the combustion chamber rising to a point at which a large amount of the mixture, flowing through opening 94, will be forthwith ignited. This combustion will result in the low temperature flame gradually changing its characteristics until a blue temperature or intensely hot flame is created, and which will be shot through with orange particles, as a consequence of certain particles of fuel entering the combustion chamber and which are still improperly vaporized. Such improper vaporization will, however, gradually be cured as the heat from the combustion chamber conducts back through tube 11 and even to some extent back to the Venturi element 14. It will1 of course, also be understood that if casing 30 is disposed in the motor compartment of the vehicle (as is preferably the case) the temperature within the latter will gradually rise and consequently the temperature of the air, entering through passages 15, will be raised. Thus, finally a flame results which is almost invisible and characterised by a bluish color familiar to all who are conversant with the art of combustion.

At the same time, it will be appreciated that the flame is of a very local nature and, in fact, after coil 9| has been (ie-energized, the convolutions of the same completely lose their incandescence so that the life of this element may be virtually indefinite. If, with the coil de-energized,

the combustion might be interrupted for short periods of time--for reasons hereinafter described-it will be found that plug |00 has reached an incandescent state such that even if the flow through the combustion ceases for a short interval of time, and the combustion is thus interrupted, the plug will immediately reignite the mixture upon the now being reestablished.

To the rear of the combustion chamber a heat exchange member ls disposed. While this element may take numerous different forms, it is preferred to employ a coil |35 having any desirable number of convoluticns and mounting a series of heat dissipating' fins or element-s |00. 'I'hese fins, as Well as the coil, may be formed of brass, and the latter may extend generally from the lower to the upper` portion of the casing 30, and preferably in a slightly inclined plane, as indicated in Figs. 5 and 7.

It has been found that with the wide temperature variations which occur in this unit, plus the effects of oxidation, the s tend to loosen with respect to the tube and, infact, a corrosive action sets in. Unless steps are taken to counteract these objections, the heat transfer unit rapidly deteriorates. To overcome any such objection, the coil unit, with the fins mounted thereon, is, prior to its assembly with the remaining apparatus, chemically cleaned and subjected to a temperature of approximately 400 F. Consequently, all volatile products are driven off and the surface is completely clean. Thereafter, the unit is dipped into a mixture of, for example, ground cobalt glass suspended in water. Subsequently the unit ls placed in an oven and maintained at approximately 1300 F. Under such temperature conditions, the coating flows into intimate contact with the surface of the heat exchanger and, in effect, forms an impervious glass film |06 which serves, not alone to protect the structure, but also binds the fins against any probability of movement with respect to the tube. Thus, no difliculties will be encountered incident to the fins vibrating or otherwise moving with respect to the tube, aside from the fact that no oxidation of the parts will occur.

To assure a maximum heat transfer between the air or other fluid passing through casing 38 of the tube and iin assembly, the latter-as afore brought 4out-is preferably mounted in an inclined plane and the upper convolution of the tube is disposed immediately adjacent the opening in the casing so that the air rushing in through conduit 31 will be forced to flow over this portion of the heat exchanger. To doubly assure a proper distribution of the air, the extension |01 of casing 36, which is coupled to conduit 31, may be provided with a baille |08 which will serve to divert a certain amount of the air towards the outer ends of the coil. Adjacent the uppermost convolution a further deector or shield |09 may extend inwardly at an angle so that assurance is created of a maximum air flow at this point. With 'such flow, the temperature of the uppermost convolution will, at worst, be barely incandescent or below the point of incandescence, and the temperature of the air will, of course, be raised to a maximum degree.

If the flow of air through casing 36 were interrupted or diminished below a certain point, the heat exchanger would, of course, reach too high a temperature, and if this condition were permitted to continue, such temperature might reach a dangerous point. In order to provide a.

' which willA amply safety factor guarding against danger to the apparatus or danger to the users of the heater, it is preferred to employ what might be termed a safety. valve best illustrated in Fig. 8. In this view, takenin conjunction with Figs. 2, 5 and '7, it will be observed that the lower end of tube |05 is coupled to a tting which includes a well portion and a cap III. The latter houses a spring` I2 bearing against a valve I I3 in the form of a sphere. The valve is prevented from moving downwardly by means of a fusible ment I i4, which is in turn retained in position by, for example spinning the lower edge of the skirt cap inwardly as indicated at H5. The spring ||2 will, of course, prevent the bore of sphere ||3 from rattling. This is especially desirable and necessary after maximum expansion of the parts has taken place. Below fitting I0 thereexte'nds a member IIB which may provide, at its upper edge, a seat |I1. As shown, the seat should preferably be raised from above the lower surface of body H0, but in any event, it will be understood that if the temperature of the parts begins to rise beyond a safe point, this will result in the gases or products of combustion emerging from the lower end of the heat exchanger reaching a very high temperature, and which will be of a As will be seen in the illustrated embodiment of the invention, a thermostat is disposed adring or elev thermostat win contact carried by value such that the ring ||4 will melt. 'Consei quently the valve will drop to its seat and further flow through the coil will be prevented. This will cause an interruption of such flow through the combustion chamber and carburetor and consequently further combustion will cease and the temperature of the parts will rapidly drop down to a safe range. l

To re-establish the oper tion of the apparatus, it will, of course, primarily be necessary to correct the condition which led to the seating of the valve. Thereafter, all that will be necessary will be to remove the old valve |I3 and to position upon fitting I|0 a new cap containing the valve assembly. As will be observed, due to the raising of the upper edge of, element IIS, a well is, in effect, created Within the base of fitting ||0 accommodate the fused portions of the ring |I4 and prevent any possibility of the same entering tube or line 33 whichis coupled to element ||6. At the same time all danger of the valve being frozen upon its seat will likewise be prevented.

It will be appreciated that widely varying conditions of vacuum or suction will exist in the intake manifold. For example, proceeding at slow speeds, and with a sudden opening of the throttle, the vacuum may drop to a very low value until the speed of the motor has againv been re-established. Likewise, if a car is proceeding up a hill and begins to lose speed, the opening of the throttle will again cause a drop in vacuum. In order to equalize to some extent the variable conditions arising as a consequence of the normal operation of the motor, it will be observed that tube 33 may have interposed in its body a section of tubing H8, which is shown in Fig. 9, and may conveniently be flexible and which mounts an apertured plug Ils, serving somewhat as a metering device or equalizing valve.

Having in mind the foregoing, it will be un, derstood that where continued and unusual operation of the motor occurs, the suction through tube 33 might be momentarily interrupted. It

is due to this eiect that the plug |00 is relied upon to initiate combustion should the latter cease.

jacent the combustion chamber and within casing 3S. This thermostat is connected in series with switch 06 and with the terminal 92 of coil 0|. This, of course, is in addition to the fact that the entire line is connected with the source of electric power such asa battery, indicated at |2| in Fig.v 13. AS also shown in the latter iig'ure, a lead |22 may tap the lead extending from the source at a'point in advance connected to a thermostatic switch |23 connected tothe motor 43.

Disregarding for the moment the latter phase of the circuit, it will be apparent that, as shown in Fig. 2, the thermostatic switch |20 may include merelya iixed arm and an adjacent bimetallic strip each carrying cooperating terminals. Under low temperature conditions, the latter will be in contact to close the circuit. This will result in energization of coill. As the temperature increases the bi-metallic arm of the tend to shift so as to move the the same out of engagement with the contact carried by the second arm. As the temperature increases, this arm will definitely shift to open the circuit; it being understood the parts are so set that an overlap occurs between the time a self-sustaining temperature is reached in the combustion chamber and the instant when the contacts separate. In this manner, it is apparent that when cold the circuit through switch |20 will beclosed, While when an operating temperature has been reached, this circuit will be interrupted to de-energize the coil and avoid further drain upon the source of elec tric supply.

As afore brought out, conditions of operation occur under which the suction is interrupted and consequently fuel does not tend to ow through the combustion chamber with sumcient velocity to maintain combustion. As also heretofore emphasized, if these interruptions to ow be of short duration then the incandescence of plug |00 will as sure a reigniting of the fuel charge upon the suction flow having been reestablis'hed. However, if the interruption to flow is continued for a sufficient length of time, it will be found that the plug |00 diminishes in incandescence, so that when the flow resumes the plug can no longer initiate combustion. Such a condition would be encountered, for example, where a vehicle continued to climb an incline with the operator endeavorlng to accelerate.

Under such circumstances, it will be appreciated that the coil 9| would have to be re-energized. This would call exterior surfaces of the combustion chamber so that the bi-metallic arm of thermostat |20 would move from any extreme position which it might have assumed back towards the stationary arm of the switch. Second, the cooling eiect would have to progress to a point at which the radial heat, as well as heat which might presumably of switch 86, and be rst for avcooling of the combustion cycle had been reinstated and the parts had warmed to an extent such that the temperature curve of the discharged air would be raised. Conditions such as the foregoing might frequently occur in hilly country to an extent such that a proper complaint might be lodged -tial or cool condition. It will be assumed that by means of the control wire 40, or its equivalent, the valve 19 has been opened and the switch Il closed, and it will, moreover, be assumed that the motor of the vehicle is functioning to create a suction through line 33, Combustion willnow occur, as afore brought out, and under the action of heat both of the strips will tend to move downwardly, as indicated in Fig. 17. The action of air flow through casing 36 and against the uppermost of the strips will tend to maintain the latter against further iiexure, while, as shown in Fig. 18, strip |25 continues to move towards the combustion chamber to an extreme position, such as has been, for example, indicated in dotted lines in that figure. As the temperature of the air entering casing 36 rises, the outermost strip |24 may shift to a greater extent towards the position assumed by the inner strip, but under all circumstances, the contacts carried by the strips will remain out of engagement.

If, however, the combustion cycle is interrupted, the innermost strip |25, which is peculiarly sensitive to the radiant heat generated by the combustion chamber, will forthwith begin to move outwardly so that the contact carried by the same will engage the contact carried by strip |24. The latter strip will not have returned to anyl appreciable extent to its initial position. Accordingly.- almost instantaneously after the combustion cycle has been interrupted, the contacts carried by the strips will. be engaged: it being emphasized that the inner strip |25 need travel only a very limited extent to effect this result,

. especially if-as hereinafter brought out-the air flow past the heat exchanger is interrupted. 'Ihis action has been shown in Fig. 19. Due to the fact that the incoming air may have cooled somewhat during this interval, and, moreover. due to the'lag which necessarily occurs in radiant heat being again generated or thrown off by the walls of the combustion chamber, the strips may return to a position such as has been illustrated in Fig. 20. From this position they will again return to positions such as have been shown in Fig. 18. v.

Now with a view to initiating the flow of air past the heat exchanger. only when the tempera- Thus, referand desirable separation ture of the latterwarrants such ilow, it willbe observed. returning to Fig. 13, that the thermo stat |23 is of a type which is open'when cooled and closed when heated. This thermostat may be disposed at a point adjacent thermostat assembly |20, or in any other desired location. In

any event, it is not directly affected by the closing or opening of switch 85. Rather only when the temperature of the parts within casing II and |25. Assoon as `and will not be cognizant of the combustion cycle being interrupted or reinstituted. However, if such interuption be -for a sumcient length of time, the motor 43 will cease to function, due to opening of the thermostat |22. Accordingly, incident to the structure described in Figs. 16 to 20, the reinitiation of the combustion cycle is accelerated. Of course, with the parts cool, as shown in Fig. 16, the fan will not operate. but may Ibegin to operate when these parts have reached the position shown in Fig. 17. The flow of air immediately thereafter may cause the upper strip |24 to tend to move in a direction opposite to the direction movement of the inner strip |25. However, this results merely in a ready of the contacts carried by the strips |24 and |25. Immediately upon such separation, the amount of current flowing through motor 43 will be increased, due to the fact that the heating coil load is relieved so that the volume of air flowing through casing 34 will be increased. However, the seating of thermostat |23 should preferably not be so sensitive as to result in an interruption of current supply to the motor 43, despite the increased speed oi' the latter. Conversely, when a. condition such as is shown in Figs. 19and. 20 occurs, the drain on the current supply, causedl by energization ot the' tion on the part of the operation of the heater.

On the other hand, if combustion is interrupted for a relatively long period of time. the fan motor will entirely cease to operate until the parts again begin to approximate a proper temperature. In this manner, the interruption will be minimized to the greatest extent.

As afore brought out, thermostat |23 may be disposed adjacent the assemblage |20. By such an arrangement, it is feasible to secure a desirable functioning of the Vailiparatus and at the same time to minimize the number of parts which are necessary. As shown in Fig. 21, the entire assembly may include bi-metallicstrips |26 and |21 and, for example, a' nxed strip |24, all of these strips carrying contacts. Strip |28 will be arranged in series with motor 4l and strips |21 and |28 will be respectively coupled to the source of current supply |2| and the coil 4|. As heretofore described, -in connection with-Figs. 16 to 20, aclosing of the switch I6 will allow current to iiow through the ignition coil to energize the latter. Strips |26 and |21 will function in a manner ysubstantially identical with that heretofore described in connection with strips |24 strip |21 has flexed to such an extent, the circuit vwill be closed through the motor 4l which will begin to function. In this manner a proper and desirable operation of the parts will occur.

In all of these several structures, the fan motor 42 preferably does not function until after the parts have reached proper operating temperatures. However, the same result may be achieved without this function being inherent to such operation. More particularly. u shown in with casing 36, may have Figs. l and l1, the outlet member |29, associated disposed in it a valve |30, with which a thermostat |3| is associated. A stop |32 may be engaged by the valve so as to prevent too great a movement thereof, while movement of the valve in an opposite direction may be prevented by simply having the width of the valve greater than the diameter .of the outlet |29. The valve may be formed with an opening |33, in line with the thermostatic element |3I. With such a construction, and simultaneous with the closing of switch 86, the circuit through the motor 43 will be closed. However, no apparent iiow of air will occur because valve |30 would be in closed position. Nevertheless, a certain amount of air would be discharged through opening |33, and as the temperature of this air increases, the valve |30 would gradually open to allow for a constantly increasing distribution of warmed air.

Finally, it will be noted, as in Fig. 12, that if it is desired to, in effect, choke or prime the unit so that a ready ignition, even under extreme cool conditions, would be assured, a downdraft carburetor might be employed. In this figure, the float chamber has again been indicated by the numeral 35. However, instead of having a tube 61 extending upwardly therefrom,l

the tube |34 extends upwardly and then, for example, sidewise to project into a Venturi member |35. The latter projects downwardly and may have its entrance end guarded by a mesh |30, while its lower end is coupled to the valve tube 11. If the operation of a heater equipped with this type of carburetor is interrupted by closing of the valve 19, gasolene or other fluid employed will continue to flow into the Venturi member until the level within the latter is equal to that of the level in the float chamber. A flow of fluid past the valve and its seat '|8 would, of course, be prevented. However, the instant the valve is opened, a relatively large amount 'of fuel would be free to flow into the combustion chamber, and under the action of the entering, air would saturate the plug and form ina pool within the well of member 90. Accordingly, as soon as the ignition coil 9| reached even a partially incandescent temperature, a low grade name would be 'established This would result in a quick warming of the parts, and a positive type of initial combustion, which would establish a self-sustaining operating temperature in a minimum interval of time.

Briefly reviewing the operation of the unit, it willbe understood that with the motor 26 functioning, the operator need only shift the rod 40,

or its equivalent, to establish a flow of gasolene into the combustion chamber and an energization of coil 9|. Thereafter, there would be established within the combustion chamber a flame of increasing temperature, and which will reach a maximum intensity within a very short time. Any surplus or condensed fuel particles would accumulate between the upwardly extending skirt 99 and the adjacent surface of member 89. In effect, a well structure is furnished at this point which, of course, assists in the establishment of the high temperature ame. Air will flow through the casing 36 and be distributed by a unit preferably of the type shown in Figs. 14 and 15, and in any desired location within the space which is to be heated. The coil |05 and its associated fins will be properly cooled by this air flow and'a deterioration of the structure of this heat exchanger is prevented incident to the glazed surface associated therewith.

If for any reason the combustion cycle is interrupted it will readily be reinitiated either by the plug |00 or the thermostatic structure heretofore described. Also, as a consequence of the control of the fan motor, which is preferably embodied in the present structure, the operator would experience no discomfort. This will be true, to some extent, even if a separate thermostat for the control of the fan motor is not employed because of the drain exerted by energize.- tion of the coil, and the consequent diminution of the supply of current to the motor 43.

If incident to failure of that motor, or for some other reason, the parts reach a dangerous temperature condition, then the safety factor, provided by the valve I3, will function to completely interrupt further operation of the unit.

At the time of assembly of the apparatus, the nozzle element 'I2 may be adjusted with reference to the Venturi member 14 to assure of a proper intake of air, which air intake is, of course, supplemented by the inflow through passage 10. Due to the sealing effect of the rear face 0f valve 19, in contact with cap 82, no packing need be employed at this point.

Obviously, numerous other changes in construction or rearrangements of the parts, might be resorted to without departing from the spirit of the invention, as dened by the claim.

Having described our invention, what we now claim is:

A combustion-type heater including a casing formed with an upper intake extension, side walls Aand an outlet, means for circulating air to be cooled through the upper opening of the said g casing, the body of the latter, and out of the lower outlet of the same, a tubular heat exchange member in said casing comprising serially connected tubes disposed one above the other in a plane inclined withrespect to the side walls of said casing, means providing a combustion chamber disposed within said casing and connected to the upper end of said heat exchange member, means for igniting fuel within said combustion chamber, means for introducing a combustible mixture into said combustion chamber, deflect-` ing means in the upper extension of said casing to direct incoming air towards said heat exchange member, and an angularly disposed shield mounted in said casing and to cooperate with said heat exchange member to create a maximum velocity flow of air over the uppermost tube of the latter and towards the casing outlet.

CARL E. MEYERHOEFER. WILLIAM c. BALLARD, JR. JOHN H. sMoo'r.

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