US2384836A

US2384836A - Heater

Info

Publication number: US2384836A
Application number: US380717A
Authority: US
Inventors: Harry B Holthouse
Original assignee: Galvin Manufacturing Corp
Current assignee: Galvin Manufacturing Corp
Priority date: 1941-02-26
Filing date: 1941-02-26
Publication date: 1945-09-18
Anticipated expiration: 1962-09-18

Description

P 1945- H. B. HOLTHOUSE 2,384,836

HEATER Filed Feb; 26, 1941 4 Sheets-Sheet 1 P 1945- H. B. HOLTHOUSE 2,384,836

HEATER Filed Feb. 26, 1941 4 Sheets-Sheet 2 Sept. 8. 1945- .4. B. HOLTHOUSE 2,384,836

HEATER Fil ed Feb. 26, 1941 4 Sheets-Sheet 3 Sept. 18, 1945. H. B. HOLTHOUSE 2,384,835

' HEATER Filed Feb. 26, 1941 4 Sheets-sheaf! Patented Sept. 18, 1945 2,384,836 nna'raa Harry B. Holthouse, Chicago, 11]., assignor to Galvin Manufacturing Corporation, Chicago.

Ill., a corporation of Illinois Application February 26, 1941, Serial No. 380,717

6 Claims.

This invention relates generally to heater systems of internal combustion type and in particular to a unit heater of internal combustion type for an automobile. This application is a continuation in part of application Serial No. 355,484, filed September 5, 1940, now Patent No. 2,286,854 issued June 16, 1942.

\ It is an object of this invention to provide an improved heater system of internal combustion type.

Another object of this invention is to provide an improved unit heater of internal combustion type for an automobile which operates entirely independently of the usual automobile engine.

A further object of this invention is to provide a heater which is simple and rugged in construction, relatively inexpensive in cost, efficient in operation, and which is completely electrical and capable of being operated on the power from a usual car battery.

A feature of this invention is found in the provision of a heater of internal combustion type for an automobile in which the temperature in the passenger compartment is controlled by varying directly the potential heat output of the heater.

A further feature of this invention is found in the provision of a heater of internal combustion type having a control system which operates to uniformly condition. all portions of the combustible fuel at all times of heater operation.

Another feature of this invention is found in the provision of a heater of internal combustion type having a fuel conditioning unit with an electrically operated heating element, in which the operation of the heating element in maintaining the conditioning unit substantially constant at a predetermined operating temperature A still further feature of this invention is found in the provision of a. combustion chamber having heat radiating fins with cavities formed therein adapted to collect any excess raw fuel which might be present in the combustion chamber.

Further objects, features and advantages of this invention will become apparent from the is controlled by an improved combination magtinued in operation for a predetermined time.

interval after effective combustion has been stopped to exhaust from the heater any combustible fuel which might be left therein.

Yet another feature of this invention is found in the provision of a heater of internal combustion type having an active pilot flame which aids in initiating the burning of the combustible mix- .ure in the combustion chamber.

following description when taken in connection with the accompanying drawings in which:

Fig. 1 is a developed view of the improved heater of this invention taken along the line i-l in Fig. 2;

Fig. 2 is a true end view of the heater shown partly in section and taken along the line 2-4 in Fig. 1;

Fig. 3 is a true sectional view of the combustion chamber as seen along the line 3-4 in Fig. 1;

Fig. 4 is a view in perspective of a partition member used in the assembly of the combustion chamber shown in Fig. 3;

Fig. 5 is a diagrammatic illustration of a control circuit for the heater of Fig. 1;

Figs. 6 and '7 illustrate diagrammatically other control circuits adapted for use with the heater of Fig. 1;

Fig. 8 is a schematic illustration showing the arrangement of the heater of Fig. 1 and the control circuit of Fig. 5 relative to the passenger compartment of an automobile.

Fig. 9 is a view partly in section taken along the line 9-9 in Fig. 10;

Fig. 10 is a longitudinal sectional view of the fuel conditioning unit shown in the heater of Fig. l; and

I Fig. 11 is a fragmentary sectional view as seen along the line ll--ll in Fig. 9.

The improved heater of this invention is of unit type and is shown as applied to the heatin" of a passenger compartment for an automobil' The heater is completely enclosed in housing means and is illustrated as being mounted below the floor of the passenger compartment. Included within the housing is a recirculating air passage arranged directly about a combustion chamber and in communication with the passenger compartment in at least twoplaces to provide for a complete circulation of air through the automobile and heater. Also enclosed within the housing are a unit for conditioning the fuel prior to its combustion, means for circulating air through the above mentioned passage. a fan for supplying air to the conditioning unit, a pump for supplying fuel to the conditioning unit, and an operating motor which is common to both the air supply and air circulating fans and to the fuel pump. The fuel conditioning unit is provided with an electrical heating and igniting element, and it is contemplated that this element and the common operating motor receive their electrical energy entirely from the usual car battery. Because of this limitation in the electrical power available to operate the heater, the motor and the air fans are of relatively small size so that the velocity of the air from the air supply fan is insuflicient to accomplish any appreciable atomization of the fuel. Likewise, the fuel pump which may be of solenoid type, develops a limited operating pressure so that fuel discharged therefrom is in substantially droplet form. In preparing the fuel for burning, therefore, the fuel conditioning unit vaporizes the fuel for mixing with the air, means being provided to retain supplied to the heater and hence the potential heat output of the heater.

With reference to Figs. 1 and 2, of the drawings, the heater is shown as being completely enclosed by a housing member iii which is divided substantially over its entire longitudinal length by a frame member ii, into a combustion compartment i2 and a mechanical compartment 53. Arranged within the mechanical compartment ii are a motor i l, a fuel pump i6, and a fuel metering device it arranged in a fuel line 2@ connecting the pump with a fuel nozzle 25, to be explained later. The fuel pump i6 is illustrated as being of solenoid type and is controlled in its operation by a breaker assembly indicated at iii and operated from the shaft iii of the motor i0. Compartment iliis in communication with a fan chamber 22 for an air circulating fan 2'3 which is operated by the motor id and is mounted on the shaft is thereof. The fan 23 functions to circulate air through passages 2d formed about the combustion chamber 25 and to discharge such circulated air through an outlet 26 which may be suitably connected with the passenger compartment 28 of an automobile (Fig. 9). Air for the fan 23 is supplied through an inlet 29 formed in the end 36 of the housing member id and opening into the mechanical compartment l3. This inlet is also suitably connected with the passenger compartment 28 so that the recirculated airirom the passenger compartment is first drawn through the length of the compartment 03 prior to being heated by its travel through the passages 26. All of the operating devices in the compartment it are thus continuously cooled by the recirculated air from the passenger compartment during the normal operation of the heater. It is to be understood, 01 course, that the inlet 29 may be open to the atmosphere so as to provide for the passage into the car compartment 01 heated fresh or outside air, or a mixture of fresh and recirculated air.

The motor ill is also common to an air supply fan 83 which is mounted on the motor shaft lii' adjacent the fan 28 but separated therefrom by a sealing or partition plate 3 1. As isclearly indicated in Fig. 1, the plate 3G in conjunction with a substantially cup-shaped end-cover member 36 for the combustion chamber 25 serves to completely seal the fan 28 and the passages 243 from i 62, while its opposite end is at the outlet 65.

the air supply fan 33. The fan 33 operates to draw'fresh air through inlet 31 formed in the end 38 of the housing l0, and to'deliver this air into an air supply chamber 39 arranged at the left end of the combustion chamber 25 as viewed in Fig. 1. The air from this chamber 39 is mixed with the fuel from the fuel nozzle 2| mounted on a fuel conditioning unit 4|, which is located in the chamber 39 at the inlet 62 of the combustion chamber, and which will be later fully described.

The combustion chamber 25 (Figs. 1, 2, 3, and 4) is of substantially cylindrical shape and includes a body member 43 of unit construction formed from a. single piece of fiat sheet steel or suitable like material. The member 33 is pressshaped to form a series of alternate peripheral sections M and radially extending fin elements (it. A fin element id is thus arranged between adjacent peripheral sections 6 3. Also as is clearly apparent from Fig. 3, each fin lli is bent double so that its outer end 87 is closed while its inner end 18 is slightly open. The side portions of each fin at the inner end 38 are brought close together so that the cavity or pocket (39 formed in the fin is in communication with the combustion passage 50 in the combustion chamber through a restricted or narrow opening. By virtue of this construction of each fin element 66, relatively narrow axially extending cavities G9 are provided over the complete length of the combustion chamber and on the inside thereof, to serve a function which will be hereinafter fully explained.

Positioned within the body member 433 is a partition member 66 comprised of a pair of

vshaped members

58 and 56. The members and ill are constructed with

fiat apex portions

55 and 56, respectively, adapted for mating back-to-bacl: engagement, with the leg portions of each

member

53 and 56 extending in opposite directions. Thus as is clearly indicated in Figs. 3 and l on attaching the members and 53 together, as by spot welding of the apex portions and 53, there is formed a partition member 58 of substantially cross shape. In arranging the member 55 within the tubular body member 63, the opposite leg portions 5i and 58 of the

members

53 and 56, respectively, are positioned within a pair of diametrically opposed fins 65, while the leg portions bio and biid are correspondingly pcsitioned in another pair of oppositely positioned fins it, the latter pair of fins being angular-l3! displaced approximately ninety degrees from first pair of fins. As shown in Fig. i the portions 5i and We of the member and the leg portion 58a of the member EEG each have an end section thereof removed. On closing the open ends of the tubular member G3 by cover plates 36 and Gil (Fig. i), therefore, to comple e the assembly of the combustion chamber a continuous passage 56 approximately four times longer than the axial length of the combustion chamber is formed within the combustion chamber. As is also shown in Fig. i. one end oi; the passage 59 is at the combustion chamber inlet A cylindrical shell or sleeve 88 is positioned about the fin ends ll to form the air passages 26 which have been previously mentioned. Heat from the fins 36 may thus be radiated into the air passages 261 to heat the air passing therethrough.

The inlet 62 of the combustion chamber 26 (Fig. l) is of somewhat smaller diameter than the combustion passage 5d and is provided with ass-gees portion 64 is located substantially opposite the inlet 69 to the chamber 66. Inlet 68 is formed with a suitable mounting portion for the fuel nozzle 2| which is connected at I2 with the fuel line 20 from the fuel pump l8. Supply air for combustion is admitted into the chamber 68 from the air supply chamber 39 through apertures I4 arranged about the inlet 59 and apertures 15 formed in the fuel nozzle 2|.

The equalizing chamber 6'! is separated at one end from the mixing chamber 66 by a partition plate 16 which is positioned transversely of the housing 63 near the sloped end wall 64. The partition member 16 is formed over its upper portion with a plurality of apertures Tl (only one of which is shown), communication between the

chambers

86 and 61 being only through these apertures. The slope of the end wall 64 is away from the member I6 so that a trough or pocket 78 is formed at the bottom of the unit 4| between the plate 16 and the sloped wall 64 for a purpose to be later explained. A The other end of the equalizing chamber 61 is separated from the combustion passage 50 by a heat insulating plate 19 positioned over the open end of the housing 63 but inwardly from such end so as to leave an annular rim or flange 82 projecting outwardly beyond the plate 19, as is clearly shown in Figs. 10 and 11. The insulating plate 19 is formed with a plurality of apertures 83 which are arranged in substantially a complete circle near its peripheral edge, communication between the chamber 61 and the combustion passage 5|] being accomplished through these apertures.

As was previously mentioned, the air and fuel supplied to the conditioning unit 4| are at low pressures which are insufficient to properly atomize the fuel for mixing with the air. In one commercial embodiment of the heater the motor i4 is rated at 3400 R. P. M. with 5.6 amperes. At this motor speed the fan 33 has a maximum output of about 5 cubic feet per minute with a velocity pressure of approximately inch of water. The corresponding output of the fan 23 with this size motor is about 65 cubic feet per minute, with the discharge of the pump [16 being about 5 cubic centimeters per minute. It is thus apparent, that the quantities of air and fuel supplied by and the operating pressures of the fan 33 and pump l6 are very low due to the limitation in the size of the motor M as determined by the electrical power available from the usual car battery. In order, therefore, to thoroughly mix the fuel and air under these operating conditions, it is contemplated that the fuel and air be heated in the mixing chamber 66 to a temperature which is sufiicient to vaporize the fuel,

with mixing resulting from such vaporization.

This heating of the air and fuel is obtained by a heating and igniting unit 84, including a tube having a steel body portion 85 and a copper extension 86 of reduced section. A resistance coil 81 extends axially through the tube portion 85 but spaced therefrom. One end 80 of the coil 81 is connected with a locking and terminal screw as which is positioned within the tube portion "but insulated therefrom by insulators 88a. and

8b. The opposite end Illa of the coil is grounded to the tube portion near the free end thereof. Coil 81 is relatively stifl so that the support at its ends is sufficient to maintain the coil in a spaced relation with respect to the inside of the tube body portion 85. However, further support is provided by a mica strip 80 or the like which is positioned within the coil. The mica strip is of flat shape and is formed with serrated sides, the coil being wound about the mica by a threading engagement of the coil with the serrations. The heating unit 84 extends axially of the housing 63 and across the chambers 65 and 61 and is supported in the end wall 64 and partition members 16 and 19, with the end 86 of the unit being "contemplated in the present invention to be about 1800 degrees Fahrenheit. The temperature in'the mixing and equalizing chambers 65 and 61, respectively, however, is at all times less than that which would effect an ignition or burning of the fuel within such chambers and is con templated to be about 300 degrees Fahrenheit. By virtue of this large temperature difference and a fine mesh screen 83a covering apertures 83, any burning of the fuel or flash back within the chambers 66 and B1 .is positively eliminated.

Operation of the fuel conditioning unit 4| at a temperature which is adapted to properly vaporize the fuel supplied to the mixing chamber 66 is accomplished by means of a combination magnetic and thermostatic switch unit which is mounted on the heating and igniting unit 8% at its reduced end 86 (Fig. 10). The combination magnetic and thermostatic switch unit is of a preassembled construction and includes a copper supporting or base member 93 of tubular shape having an annularly extending flange 94 at one end thereof. Stacked in succession axially of the copper tube 93 and against the annular shoulder 94 are an aligning element 95, a bi-metal or thermostatic element 96, a copper washer 91, an insulator or mica washer 93, a conductor unit 59 for the heating and igniting unit 3%, a magnetic or induction coil |0il mounted on but insulated from a spacer or core member Hi i, a mica washer m2, an iron washer W3, a conductor arm Hi4, a mica washer IE5, a second coil unit I06 having a spacing member I07, a conductor unit or switch arm I08 for the pump iii, a steel washer I09, a mica washer H0, and another steel washer IN. All of the above defined parts mounted on the copper sleeve 93 are retained in their assembled position by peening the end H2 of the tube 93 against the outside steel washer I. That portion of the switch assembly included between the mica washers 98 and H0 is insulated from the copper tube 93 by an insulating sleeve H3 which may be formed of mica or the like.

Assembly of the magnetic and thermostatic switch unit with the fuel conditioning unit 4| is accomplished by slipping the copper tube 93 over the reduced section 86 of the heating and igniting unit 84, the aligning member 95 being of a form to engage an annular recess 2 lAformed in the fuel nozzle 2|. This engagement of the variable resistance I00.

member 95 with the nozzle 2| serves both to align the magnetic and thermostatic switch unit in a position relative to the other parts of the conditioning unit and also to maintain the fuel nozzle 2| in a supported position in the inlet 69. The switch unit is held in place on the tube end 86 by locking means 880 threaded on the screw member 88.

The battery switch arm I is of substantially straight form and is provided with contact points I I0 and I I5 on opposite sides thereof, contact I I0 being engageable with a contactor M8 on the switch arm 99 for the heating and igniting unit, and the contact point IIO being engageable with a contact III provided on the switch arm I00 for the pump' I0. As shown in Fig. 10 contacts H5 and III; are normally closed while contacts IIO and Ill are normally open. Although the supporting portions of the arms 00 and I00 are axially spaced a relatively large distance from the switch arm I00, because of the coil windings I00 and I06 positioned therebetween, the upper portions of the arms 90 and I00 are inclined inwardly toward the arm I00 so that all of the contacts IIO-I I? are relatively close together. Arm I00 is formed at the top thereof with an extension I it which is engageable with the upper end of the bi-metal element 00, and specifically with an insulator portion IIO thereon. The bimetal arm 00, by virtue of its direct support on the end 80 of the heating and igniting unit 00 is immediately responsive to the heat conditions of the heating unit and is adapted to move toward the right, as viewed in Fig. 10, as the coil 0?? becomes heated. On heating of the element 011, therefore, the conductor arm I 00 is moved toward the right and out of contact with the arm 00 and toward the arm I08 as will be later fully explained.

Energization of the heating and igniting unit 00 is accomplished by its connection with a suitable electrical source such as a car battery I (Fig. 5) the circuit from the battery including a conductor I2I, a double throw main switch I22, conductors I20 and I00, switch arms I00 and 00, conductor I 25, coil windings I00 and I00, conductor I20, and coil 0?, the circuit being completed to ground. Conductors I23 and I20 and the switch arm I00 are also common to the circuit for the fuel pump I0. This circuit from the switch arm I00 is completed through switch arm I00, conductor IE7, fuel pump I0, conductor I20, breaker assembly I0, conductor I20 and switch I22 to ground. The conductor I23 from the main switch IE2 is also common to the circuit for the motor I0, th 'motor circuit including further conductor I30, the armature and field for the motor I0, conductor IIJI, conductor I32 and a The motor circuit also includes a time delay switch I which is shunted about the switch I22 and includes an induction coil I05 connected in series between conductors ISI and I32. This time delay unit will be later ex- Dlained.

In operating the heater the main control switch I22 is initially closed to in turn close the circuit for the motor I0 and also the circuit for the heating and igniting unit 00 through the connections just described. This closing of the circuit for'the heater element 07! energizes the induction windings I00 and I00 to magnetize the arms 00, I00 and I00. These arms, therefore, are constructed so as to be efficiently magnetized without impairing their conducting capacity. Because of this fact the battery switch arm I00 includes a .a flux transfer element IOI'.

silicon-steel portion I30 and a copper portion I31; the silicon steel portion I38 being readily magnetized, and the copper portion serving to carry the current from the battery I20 to the switch arm 09. The switch arm 09 is similarly provided with a silicon steel portion I38 and a copper portion I39 and includes further a stationary magnetic carrier IlI composed of iron. This carrier increases the magnetic flux transfer from the coil I00 to the pole face I40 formed over a part of the silicon steel element I38. The switch arm I00 includes a silicon steel portion I08 and A copper current carrying element for the switch arm I00 is not required since the current necessary to operate the pump it is relatively small compared to that needed for the coil 81.

In the construction of the conductor arms 09 and I00, the steel portions I38 and I38 are formed with pole faces I00 and I00, respectively, which are positioned opposite corresponding pole faces I00 and I03 formed on the flux transfer elements HM and IOI'. In practice it is contemplated that the air gap between each pair of corresponding pole faces be about .005 to .020 inch. Since each magnetic carrier HM and MI functions to lower the reluctance of the magneticpath from a corresponding coil I00 and I00, respectively, to a pole face I00 and I00 respectively, the magnetic flux at such latter pole faces is greatly increased, by virtue of the flux transfer between the pole faces I00 and I03, and I00 and I00.

As is clearly shown in Fig. 10 the coil cores IOI and I0? are insulated at their adjacent ends by the mica washers I02 and I05, respectively, from the battery arm I00, but are in magnetic connection at their outer ends with the arms 00 and I 00, respectively. Thus on energization of the coils I00 and I00 the pole faces I00 and I00 are magnetically charged with like polarity, while the portion I00a of the arm I00 between such pole faces is charged with an unlike polarity. On closing of the main switch I22, therefore, the arms 00 and I00 are magnetically attracted to the arm I00 whereby to close the contacts IIO and II? and to magnetically lock the normally closed contacts I I0 and I I0. Closing of the main switch I02, therefore, effects a substantially simultaneous operation of the fans and 03, fuel pump I0 and heating and igniting unit 00. If on closing of the main switch I22 the circuit for the unit 00, for some reason, does not become energized the windings I00 and I00 are rendered inoperative to magnetically charge the switch arms 00, I00 and I00 so that contact III is not attracted toward the contact IIO. The circuit for the fuel pump I0 thus remains open through the normally open position of the contact points I I0 and I II so long as the coil 0? is not capable of being energized.

Closing of the motor circuit provides for the closing of the time delay unit I00 by virtue of the energization of the winding I05 as will now be explained (Fig. 5). The time delay or thermostatic and magnetic unit I00 is connected in the motor circuit by conductors I00 and I0? which are connected to conductors I2I and I20, respectively. The winding I05, previously mentioned, is wound on an iron core I00 which is mounted on one portion of a substantially C-shaped magnetic yoke I00. Suitably mounted so as to extend over the gap I50 in the C-shaped yoke I00 is a bi-metal conductor armature IEiI. The armature IEiI is connected at one end I52 to the yoke, but is insulated therefrom, the end I52 being connected also with conductor I00. The opposite end of the i 2,384,888 armature has a contact I53 engageable with an insulated contact I64 mounted on the yoke I48 and connected with conductor I". On energization of the winding I36, therefore, the yoke I48 is magnetically charged so that a high magnetic flux occurs at the gap I66 of the yoke. This magnetic flux is of suflicient intensity to attract the bi-metal armature II inwardly toward the yoke an amount sufficient to close'the contacts I58 and I54, thereby also closing the motor circuit about the main switch I22. It is thus seen that the shunt circuit is closed substantially concurrently with the closing of the switch I22. However, when the switch I22 is closed it acts to shortcircuit the shunt circuit. Although the motor circuit, therefore, is closed both through the switch I22 and about such switch, but very little current flows through the shunt circuit during the normal operation of the heater. From the above description it is seen that when the heater is started by closing the main switch I22, the circuits for the heating and igniting unit 66, fuel pump 6 6, and motor I6, and for the switch unit ltd in the motor circuit are all closed at substantially the same time.

On starting of the fan 33 and pump it, respectively, air and fuel is supplied to the chamber 66 (Fig. 10), the nozzle'2i and air ports it being arranged to direct such air and fuel toward that portion of the unit 66 within the chamber 66 and the inclined end wall portion 66. The partition member l6 and the housing 66 for the fuel conditioning unit ii are provided in a suitable heat conducting material such as copper so that the heat from the heating and igniting unit 84 is readily transferred to all portions of the conditioning unit, the variation of the temperature within the chambers and their surrounding walls relative to the heating unit 66 beingabout 10 degrees Fahrenheit. Thus since the wall64 is at substantially the same temperature as the heating unit 66, the fuel in the mixing chamber 66 is heated by its contact with both the unit 66 and the wall 66 to facilitate its mixing with the air. The resultant air and fuel mixture passes through the apertures 'II in the partition plate I6 into the equalizing chamber 67 and thence through the perforations 63 in the insulated plate I6 into the end portion 62 where it is' ignited by the heat at the end 860. of the heating unit 66. As the heating unit 84 continues in operation its temperature increases to in turn increase the temperature in the chambers 66 and 67.

As was previously mentioned, the difference in the temperatures of the chambers 66 and 61 and the heating unit St is only about 10 degrees Fahrenheit, so that the temperature of the unit 84 is essentially the same as the temperature in the mixing chamber 66, which latter temperature is controlling in the conditioning of the fuel for a burning. However, for convenience and clarity,

only the temperature of the heating unit 64 will be referred to in the following description with respect to the action of the thermo-magnetic control switch. With the heating of the unit 64 to a temperature of about 200 degrees Fahrenheit, the fuel contacting that portion. of the heating unit in the chamber 66 and the end wall 64 is substantially immediately vaporized by the heat in these parts, the angular slope or inclination of the wall 64 deflecting the fuel against the partition wall I6 to further vaporize any remaining fuel particles. This vaporization of the fuel is accelerated somewhat by breaking up the fuel stream in the nozzle 2|. This is accomplished by the air from the supply chamber 39 passing into the nozzle through the apertures I6, this air entering the chamber 66 with the fuel. Any raw or free fuel particles which are not immediately vaporized are collected at the bottom of the chamber 66 in the fuel trough or cavity I6. Because of the heated condition of the partition wall I6 and end wall 64, the raw fuel thus collected is additionally heated and is further exposed to the warm supply air circulating within the chamber 66 to facilitate its passage into the chamber 61 in a vaporous form. Any passage of raw fuel particles into the equalizing chamber 61 is thus substantially eliminated. The equalizing chamber functions to equalize the velocity flow and pressure of the mixture so that the mixture entering the portion 82 of the fuel conditioning unit- 4| has substantially uniform characteristics and is free of any isolated rich or lean portions.

During this period of operation the bi-metal element 96 moves slowly toward the right, as viewed in Fig. 10, moving the contact H5 away from the contact I i6 and moving the closed contacts H6 and Ill toward the right. When the temperature of the unit 86 reaches a value of about 200 degrees Fahrenheit, which represents a minimum operating temperature at which the fuel is advantageously mixed with the air, contacts I I5 and H6 are opened by the action of the bi-metal element 66, the contacts lit and ill continuing closed. Since the magnetic windings I00 and I66 continue to be energized only so ion as the circuit for the heating unit 66 is closed. it is apparent that opening of the contacts H6 and H6 by the bi-metal arm 96 is against the magnetic attraction between the conductor arms 99 and I64. By virtue of this action of the arms 96 and IM an abrupt and clean break is accomplished between the contacts H5 and H6, with the contact H5 being sumciently removed from the contact H6 when the break occurs to prevent any fluttering action between these contacts. Undesirable arcing between the contacts is thus entirely eliminated whereby to prevent the occurrence of any spark adjacent the mixing chamber and to prolong the service life of the contacts. Also the circuit for the heating unit 84 is thus positively controlled between very definite temperature limits. Since the arm I64 on opening of the circuit for the heating unit has been moved to the right by the action of the bimetal element 96, it is in a position to maintain closed the contacts H4 and Ill. Thus with the circuit for the coil 81 open the contacts H6 and Ill are held closed by the pressing action of the bi-metal element 96 and not by any magnetic attraction between the arms I64 and I66. The

fans

23 and 33 and pump 66 thus continue in operation after the circuit for the coil 81 is opened by the thermal element 96.

The operation of the heater with the circuit of the heating unit 84 deenergized continues until the temperature of the heating unit 64 falls below about 200 degrees Fahrenheit. When this temperature drop occurs the bi-metal element 96 is cooled and moved toward the left, as viewed in Fig. 10, an amount sufficient to permit a closing of the contacts H5 and H6 without opening of the contacts H4 and I ll, these contacts being immediately magnetically locked by virtue of the energization of the windings I06 and I66. On. closing of these contacts, the circuit for the heating unit 64 is closed, the fuel pump i6 and

air fans

22 and 33 continuing in operation, the contacts I and II I in the fuel pump circuit being gnetically locked concurrently with the magnetic locking of the contacts Hi3 and lit. When the temperature of the unit 84 and hence of the chamber 88 is again increased to about 200 degrees Fahrenheit, contact is again broken between the arms til and M4 to again open the circuit of the unit 86. This controlld operation of the fuel conditioning unit 6! continues at all times during the normal operation of the heater, which operation is stopped by the opening of the control switch n22.

Although practically all of the fuel in the mixture leaving the ecuali chamber Bl is in avaporous form at times during heater operation raw fuel might enter the combustion chamber. In the event any raw fuel should get into the combustion chamber it is collected in the nu cavities 69 and heated to a vapor by the accumulated heat in the fins. vaporous iuel then enters the combustion chamber to be burned. The restricted opening co to each cavity 48 prevents any flash-beck or burning oi the fuel in the cavity, by virtueoi the fact that insufiicient air is supplied to the cavity to support combustion, and by the additional fact that the restricted cavity opening permits at building; up of a vaporous pressure in the cavity which is greater than the pres sure in the combustion chamber. The vapor in forced into the combussure thus tending; to combustion chamber. uel in the combustion and all of the fuel voporous state so that proceeds both quietly tion c maintain crsplishinzr an even end 1 found in the provl- ..0 near the coil enol [lilo M the operation oi the heating Eng writ Gil it has been iounol the iuel striking coil end its may irn= :nedictely cool such end to a temperature which is insuificient to support combustion, and hence insuficient for ignition purposes. To overcome this clifilculty. and to ermit the use of a light wire in the construction or the coil ill], there is provided pilot tube supported in the insu= later or ceramic plate l d and having one end thereof positioned within the equali chamher (Ell and its opposite end arranged in the tube portion 85 at 9. position substantially opposite the coil end 68s. This pilot tube 1165 is of a size to control or meter only that amount of vaporous fuel from the chamber fill which can be ignited by the coil end 86a without eflecting any appreciable cooling of the coil. The mixture passing through the tube use into the igniting zone at the coil end Boo is thus more positively and readily ignited than the fuel leaving the chamber 67 through the apertures 88 and acts at all times of heater operation as a pilot light relative to such remaining ifuel mixture.

' I. D. of .05 inch; The tube l55, therefore, functions tomewr or control the ignition of that amount of vaporous mixture which is capable of aasaeso being ignited by the coil end 80a without appreciably cooling such coil end.

As is clearly indicated in Fig. 10, the outlet of the tube "55 is arranged at the intersection of a pair of slots I58 and lil formed in that portion of the tube 88 which projects outwardly from th insulator 78. In the practice of this invention it is contemplated that the air and fuel supplied being more lean than the mixture in the equalizingchamber 81 because of the expansion of the mixture in passlng through the apertures 83 into 7 the portion 62. Since in practice the condition= ill It is resdily apparent that the use of a lighter wire in the conins unit (ll is normally operated in a substantially horizontal position, the mixture of most even consistency in the equalizing chamber fil has been found to occur at substantially the hori zontal center of such chamber. It is contern plated, therefore, that the tube lilo be positioned at such horizontal center, so that the outlet thereof is to on side oi the coil end. 8015.

AS previously mentioned the switch acts to short-=circuit the unit i so that but very little current through the lot-metal condoctor armature Mi during normal heater clper ntion 5). 'Cln opening of the switc however, all of the current for operating the motor 66, flows through the shunt circuit and hence through the armature, being understood that the circuits for the fuel pump i6 and heating unit 813 are rendered inoperative. The shunt circuit thus operates to continue the ill in operation after the pump to and heating unit 84. have been deeriergized. The current which now flows through theshunt circuit is sui'iiciently high to appreciably heat the bi-rnetcl armature lllhwhich is'constructed so as to move outwardly from the yoke I189 in response to such heat. Thus when the armature lot is heated to a predetermined temperature value, it is under tension sumcient to overcome the magnetic ottroctlon at the gap 559 and to break the connection between contacts M53 and 55d, thus opening the shunt circuit and stopping the operation of the motor M. It sometimes occurs that the heat derived from the current flow in the armature tilt is insumcient to quickly move the armature to its open position. To assure a fast and positive action of the armature ltll there is provided a heater coil H, arranged in heat exchange relation, with the armature lot and in series connection therewith. During normal operation oi? the heater, with the switch l22 closed, the current flow through the coil H is too low to efiect any appreciable heating of the armature 950. However, when switch 622 is opened the current flow through the coil H is increased. Thus the armature liil is moved to an open position by virtue of the heat from the current flow therein and the heat from the heating coil H. It is apparent, of course, that the time required for the armature dbl to open the contacts lot and lilo is dependent upon th number of windings in the magnetic winding ltlll and the heat characteristics of the bi-metal armature lbl. By a relative construction of the armature lei and winding I35, therefore, the switch unit I34 may be adapted to delay the opening of the motor circuit for any desired period of time, a time of two minutes being .used in the above-noted commercial em bodirnent.

The continued operation of the motor I4, after the fuel pump I6 and heating unit 84 have been deenergized, operates the fan 33 so as to exhaust any combustible mixture which might be in the combustion chamber on opening of the main control switch I22. Since the-mixture which remains in the combustion chamber is usually burned at a slow rate by the residual heat in the chamber, burning proceeds with an odor which is very disagreeable. A continued operation of the fan 33, therefore, entirely eliminates any after-burning of residual mixture portions and further eliminates any possibility of a later explosion inposition of maximum or high motor speed with the heater on subsequent starting thereof. It is seen, therefore, that the armature vI5I of the combination magnetic and thermostatic unit I34 is magnetically locked in a closed position on closing of the motor circuit by the switch I22 and that it remains magnetically locked until moved to its open position in response to the heat produced by a current flow therein. Because of this construction the action of the armature in stopping the motor I I is very positive, since the contacts I53 and I54 are immediately widely separated when the armature is opened. This positive action is assured further by an insulating stop I50 mounted at one side of the yoke gap I50. The stop I58 prevents the armature I5I from moving to its closed position except when it is so moved by the magnetic pull at the gap I50. Heating of the armature thus functions only to open the armature, its closing being accomplished entirely by the magnetic attraction at the gap I50.

From the above description and consideration of Figs. 1 and 5, it is clearly apparent that the rate of operation of the

fans

23 and 33 and fuel pump I6 depends on the speed of the motor I4. In the operation of these parts, it has been found that when the speed of the motor is decreased the rate at which air is discharged or displaced by

th fans

23 and 33 decreases proportionately faster than the rate at which fuel is discharged from the pump I6. In other words, the fuel to air ratio as provided by the pump I6 and fan 33, increases directly with a decrease in the motor speed so that the richness of the mixture in the heater increases as the motor speed is reduced.

Since the rate at which air and fuel is supplied to the combustion chamber varies directly the potential heat output of the heater, manual means are provided to control the motor speed to in turn control the temperature in the space being heated, which in this instance, is the car compartment (Fig. 8). As was previously mentioned, the circuit for the motor I4 includes a resistance I33. By moving a grounded control arm I62- across the resistance I33 the speed of the motor the desired reduction in the speed of the motor for starting purposes being accomplished entirely by the resistance R in the conductor I23. On the cutting out of the heating unit 84 by the action of the thermo-magnet control switch (Fig-10) the motor I4 operates at its maximum speed to in turn supply a maximum amount of air and fuel to the heater. The heater thus operates with a maximum otential heat output. As the temperature in the car compartment 28 increases thecontrol knob I65 is actuated to move the arm I62 to the medium or low speed motor position to in turn decrease the amount of air and fuel supplied to the combustion chamber and the available heat from the heater. This reduction occurs concurrently with a reduction in the amount of air being circulated through the passages 24 by the fan '23. Thus not only is the temperature of the heated air reduced, but its quantity is also reduced so that a double control of the temperature is obtained by the single control of the motor I4.

From a consideration of 8 it is seen that the control circuit of Fig. fir'equires three lead wires from the housing I63 to'the heater, namely, conductors I29, I23, and I3I. A modified form of this circuit is shown in Fig. 1 in which but two leads are needed to completely connect the heater with the switch mechanism in the housing I63. Since the two circuits are similar in many respects, similar numerals of reference shall be used to designate similar parts. The circuit for the motor I4 from the battery I20 includes a conductor I66, switch I22, conductor I68, resistance control arm I62, conductor I63 and a ground conductor I10. The circuit for the coil 81 of the heating unit from the battery I20 includes conductor I36, switch I22, conductor I1I, control arms I04 and 99, coil windings I00 and I06, conductor I12 and ground conductor I13. The circuit for the fuel pump I6 is common with that of the coil 81 up to the control arm I04, the circuit from the control arm I04 comprising the control arm I08, conductor I61,-

breaker assembly I8 and ground conductor I14. On closing of the main switch I22, therefore, the motor I4, pump I6, and heating coil 81 are simultaneously energized, the switch arms '99, I04 and I08 operating at all times in the manner above fully described in connection with Figs. 5 and 10.

As illustrated in Fig. '7 the circuit for the motor I4 includes a time delay unit I15 which is shunted about the switch I22 by conductors I16 and I11, the conductors I11 and I16 being in series connection with the time delay unit ns and with the motor resistance I33. The time delay unit includes a bi-metal conductor arm I18 connected at one end to an insulator block I19 and having a contact IBI and a pole, face I82 inspaced relation near its opposite end. A mating conductor arm I83 is also secured at one end to the insulator block I13 and is provided at its opposite end with a contact I8I and pole face I82. Each pole face I82 and I82 is comprised of a permanent magnet which may be composed of Alnico or other like closes the contacts lBi and i8! thereby closing the shunt circuit, the circuit being retained closed by the magnets I82 and I8? regardless of later H movement of the projection I84 out of engagement with arm I18 during the normal rotation of the knob I65 to control the heat output of the heater.

The shunt circuit is thus closed concurrently with the closing of the circuits for the heating coil 81, fuel pump it and motor M by the switch 522, the control knob WE functioning also to operate the switch I22. The switch I22, however, serves to short-circuit the time delay unit I15 so that but little current flows therethrough during normal heater operation. On opening of the main switch I22 by the control knob I65, the projection I84 is moved to a position out of engagement with the contact arm lit, the contacts Isl and MI remaining closed by virtue of the magnetic attraction between the pole faces M2 and "i822 operation after deenergization of the pump l5 and the heating coil 8?. However, since opening of the switch B22 increases the current flow through the time delay unit W6 and hence through conductor arm lit, the arm becomes heated. This heating of the bimetal arm llil continues until it is sufficiently flexed to overcover the magnetic attraction between the pole faces H32 and i822, at which time the contacts liil and ltll are opened, thus opening the circuit for the motor i i. In some instances the bi-rnetal arm ill? may be somewhat lagging in its movement to open the contacts Hill and till. This possible action of the arm W8 is entirely The motor it thus continues in eliminated by the arrangement adjacent thereto of a heater coil H, which is connected in se= ries with the arms H8 and m3.

By virtue of the calibrated resistance R in the conductor ltd the circuit of Fig. 7 also functions to provide for an automatic choking effect in the heater on energization of the heating coil ill. lit is to be understood also that the motor id is common in the operation of the fuel pump it and of the

air fans

23 and 33 so that the heat output of the heater is varied directly by move-' ment of the knob ltd to its various heat control positions indicated as high, low and medium.

A further modified form of control circuit adapted for use with the heater of this invention is illustrated in Fig. 6. This control circuit is substantially similar in all respects to the control circuit in Fig. 7 except for the substitution of a pump relay unit me for the winding ills of the thermo-magnetic switch unit. The pump relay unit let includes a magnetic yoke it? which is magnetically charged by an induction winding 68d connected in series in the conductor ill. The yoke member it'll is of substantially C-shape, a conductor armature I89 being connected at one end of the yoke in a manner to extend over the gap formed therein, a contact it! at the free end of the armature being adapted for engagement with a contact I92 connected by conductor I93 to conductor l6? of the fuel pump circuit. The circuit through the pump relay unit I86 is completed by connection of the conductor i7! directly with the yoke member is? as at H95.

On closing of the main switch l22, therefore, the motor Hi, the heating coil 81 and the fuel pump it are simultaneously energized, the energization of the coil circuit providing for the magnetic closing of the armature I89 and a consetractable positions. This magnetic attraction quent closing of the contacts i9! and it?! to close the fuel pump circuit. Thus on initiation of heater operation, the fuel pump circuit is closed through the pump relay I86 and while the switch arms I04 and I08 are still in an open position.-- However, when the thermal element 98 is suflicientiy heated to move the arms M4 and 808' into contact, the circuit for the pump I8 is completed through these two switch arms so that. later deenergization of the coil 81 on the opening or the arms Hit and 99 in response to movement of the thermal element 56 does not ailect the operation of the fuel pump IS. The fuel pump l8, therefore, remains in operation at all times during normal heater operation;

0n opening 01' the main switch I22, the heating coil 87 and the pump l8 are immediately shut down, but the motor It continues in operation for a predetermined time by virtue of the time delay unit I15 fully described above. The pump relay unit I86, therefore, operates only to eliminate any time delay in the starting of the pump at the time the heater is started, and is entirely short-circuited as soon as the switch arms Mid and M18 make contact. It is contemplated that the coil its be such that the load of the coil bl is necessary to sufficiently energize the yoke Hill for magnetically closing the armature its.

The invention thus provides a unit heater of internal combustion type whose control is entirely electrical and which can be operated irom a small source of electrical energy such as the usual car battery. Control of the heater is accomplished entirely by a compact unit located on the automobile dashboard, while the heater as a unit may be mounted in a plurality of positions about the vehicle passen er compartment. All of the heater parts are completely enclosed within a single housing means and connections.for the operation of the heater are required only to a source of fuel and electrical supply. The unit is compact and rugged in construction, inexpensive to manufacture so as to be commercially available at low cost, and adapted for operation on any automobile rtardless of the type of such automobile. This is due to the fact that the heater operates entirely independently of the automobile engine, and does not, depend for its operation on any predetermined suction or force pressure provided by such engine. The relative temperature values used in the above description are representative of one type of fuel, and of course will vary for different kinds of fuel. Although the inventio has been described and illustrated specifically with reference to an automobile, it is to be understood that it may also be used in the heating of trailers, small work shops, and the like. It is also apparent that the heater parts may be relatively changed in size to increase the heat output of the heater so that it can be utilized for domestic heating purposes.

It is to be understood also that only preferred embodiments of the invention have been illustrated and described herein, and that alterations and changes therein may be made which are within the full intended scope of this invention, as defined by the appended claims.

I claim:

said inlet and having 7 2,384,836 being arranged between the inlet of said combustion chamber and said mixing chamber, perforated partition members at each end of said equalizing chamber, a combination heating and igniting unit supported in said partition members and having a heating portion in said mixing and equalizing chambers and an igniting portion near the inlet of said combustion chamber, said heating unit being adapted to cause the fuel in said mixing chamber to be heated to a vaporizing temperature for mixing with said air so that substantially all of the mixture is in a vaporous form when it passes into said equalizing chamber, whereby the heat in said equalizing chamber retains said mixture in its vaporous form, and means for carrying a portion of the mixture from said equalizing chamber to the igniting portion of said combination unit, whereby the mixture from said latter means is ignited by said igniting portion to initiate burning of the remainder of the mixture passing from said equalizing chamber into said combustion chamber. I

, 2. In a heater of internal combustion type, a

tubular combustion chamber having the inner surface thereof formed with longitudinally extending angularly spaced cavities with openings in communication with said combustion chamber, each of said cavities having the longitudinally extending sides thereof converging together heat therein.

3. In internal combustion heating apparatus provided with a combustion chamber, a fuel con-' ditioning and ignition unit including a tubular member, means including a perforated partition wall for dividing the space within said member into a fuel and air mixing chamber and an equalizing chamber through which the mixture of fuel and air is transmitted from said mixing chamber into said combustion chamber axially of said tubular member, an ignition element disposed adjacent the outlet end of said equalizing chamber, and a memberzpartially housing said ignition element and having an opening in the wall thereof through which a portion of the fuel and air mixture traversing said equalizing chamber is directed into engagement with said ignition element for ignition.

4. In internal combustion heating apparatus provided with a combustion chamber, a fuel conditioning and ignition unit including a tubular member, means including a perforated partition wall for dividing the space within said member into a fuel and air mixing chamber and an equalizing chamber through which the mixture of fuel and air is transmitted from said mixing chamber into said combustion chamber axially of said tubular member, an ignition element disposed adjacent the outlet end of said equalizing chamber, and a second tubular member surrounding said element and havingan end which opens into said combustion chamber, said mixture being adapted to surround said second tubular member and to flow into said combustion chamber axially thereof, said second tubular member having one opening in the wall thereof through which a portion of the mixture traversing said equalizing chamber is directed into engagement with said ignition element and having a second opening in the wall thereof at a' point outside of said equ'alizing chamber through which a portion of the mixture entering said combustion whereby any fuel particles in said combustion chamber will collect in said cavities and be vaporized by the heat therein, and a partition structure for dividing said chamber into a plurality of passages and including walls each having an edge portion held between the converged edge portions of the sides of one of said cavities.

6. In internal combustion heating apparatus, means defining a tubular combustion chamber having the inner surface thereof formed with longitudinally extending angularly spaced cavities with openings in communication with said combustion chamber, each of said cavities hav- 4 ing the longitudinally extending sides thereof converging together to form a slit-like opening,

a means for supplying a substantially completely vaporous mixture of air and fuel to said combustion chamber for burning adjacent said cavities, whereby any fuel particles in said combustion chamber will collect in saidcavities and be vaporized by the heat therein, and a partition structure dividing said chamber into a plurality of fluid connected passages and including a plurality of V-shaped members joined at their apexes centrally of said chamber and provided with walls each having an edge portion held be-, tween the converged edge portions of the sides of one of said cavities.

HARRY B. HOLTHOUSE.