US3457021A

US3457021A - Variable heat output catalytic heater

Info

Publication number: US3457021A
Application number: US750255A
Authority: US
Inventors: David J Gladden; William J Marsh
Original assignee: Coleman Co Inc
Current assignee: Coleman Co Inc
Priority date: 1968-08-05
Filing date: 1968-08-05
Publication date: 1969-07-22
Anticipated expiration: 1986-07-22

Description

July 22, 1969 D. J. GLADDEN ETAL 1 3,457,021

VARIABLE HEAT OUTPUT CATALYTIC HEATER Filed Aug. 5, 1968 v 3 Sheets-Sheeti 40 FIG. I

2a Ll" 54 H If." I 50 1 56 8 s a\ 5 60c O START I I MEDIUM 7s '36 4s LOW OFF 0 I 26 l:\"\-"1i, i'l()l\8: DAVID J. GLADDEN WILLIAM J. MARSH BY: I

ATT'YS July 22, 1969 GLADDEN ET AL 3,457,021

VARIABLE HEAT OUTPUT CATALY'ITC HEATER Filed Aug. 5, 1968 3 Sheets-Sheet 13 FIG?) g I! III A IAW'IiM/URS:

DAVID J. GLADDEN WILLIAM J. MARSH AT T' YS y 1969 D. J. GLADDEN ET AL 3,457,021

VARIABLE HEAT OUTPUT CATALYTIC HEATER 3 Sheets-Sheet :5

Filed Aug. 5, 1968 Q N S m E R s W D A w D M T w M J M w w 1 M W & J o A irii. m L \N M l D W FIG. IO

United States Patent US. Cl. 431315 16 Claims ABSTRACT OF THE DISCLOSURE In combination with a catalytic heater there is provided means for controllably and selectively varying the heat output. The combination includes a stationary inner wick tube slidably receiving a capillary action wick through which liquid fuel is transferred from a base reservoir to a vapor collection space within the catalytic head, and a support tube enclosing the wick tube and providing a space therebetween which is in communication with the upper portion of the reservoir and the lower portion of the head vapor space to maintain equal vapor pressure in the fount and head while the liquid fuel is being transferred. Lever means is pivotally mounted on the outer tube and provides an inwardly extending actuating arm and an outwardly extending control arm. The pivot mounting preferably provides a substantial vapor seal, and the wick means preferably extends substantially to the bottom of the reservoir in all of the positions of the wick.

CROSS REFERENCE This application is a continuation in part of our copending application, Ser. No. 554,074, filed May 31, 1966, now abandoned, and entitled Adjustable Catalytic Heater.

BACKGROUND An improved kind of catalytic heater is disclosed in US. Patent 3,343,586. The heater is characterized by improved operating characteristics, especially by its capacity to sustain a substantially uniform high rate of fuel consumption from full fuel charge to empty. While this heater can be manufactured in various sizes for greater or lesser heat output, no means was provided for controllably and selectively varying the B.t.u. output once the size of the heater had been established. Consequently, it was necessary to operate such heaters at the maximum rated capacity, even though the user might have preferred to have less heat at a particular time.

As described in said Patent 3,343,586, the capillary action wick, which may be a non-combustible wick, is fixedly mounted within a wick tube by some suitable means, such as staking with lances formed in the wall of the wick tube and extending inwardly into the wick. By precise positioning of the upper end portion of the wick in relation to the catalytic combustion element of the head, and by incorporating the other features disclosed in said patent, a uniformly high B.t.u. output could be produced. Specifically, it was found desirable to have the Wick cross-sectioned to substantially fill the wick tube, thereby maximizing transfer of the fuel in liquid form and at the same time minimizing transfer of the fuel in vapor form. A second tube is provided around the wick tube, and preferably being concentric therewith, and providing an annular space therebetween. Small ports were provided near the bottom of the tube to permit the pressure within the annular space to equalize with the pressure in the upper portion of the fount or reservoir. The upper end of the annular space communicated with the vapor collec- 3,457,021 Patented July 22, 1969 tion space within the combustion head, preferably through a porous absorbent packing material. This arrangement provided for pressure equalization between the interior of the head, that is, the vapor collection space, and the annular space between the tubes, which in turn resulted in pressure equalization between the fount and the head. At the same time, only a negligible amount of fuel vapor was transferred through the annular space between the tubes. The outer tube also provided a hermetic seal to the base housing and to the head thereby effectively preventing the escape of any fuel vapor from the annular space, except into the combustion head where it would be burned along with the other fuel vapors produced by evaporation from the upper end of the capillary wick. It was also found desirable to omit any packing from the fuel reservoir, and to have the fuel therein in open flow relation with the wick, preferably extended to the bottom of the reservoir for complete utilization of the fuel therein without regard to liquid level.

THE INVENTION This invention is based in part on the discovery that most, if not all, of the desirable operating characteristics of the catalytic heater of said Patent 3,343,586 can be retained while providing for a selective variation in B.t.u. output, the variation being obtained by selective positioning of the capillary wick means, and more particularly of the amount or extent of the wick means projecting into the combustion head. In other words, it was found that a range of wick positions was possible where different but substantially constant B.t.u. output could be obtained. For example, a catalytic heater could be produced having a maximum heat output of around 8,000 B.t.u., and by selectively lowering the wick to reduce the proportion thereof projecting into the combustion head, the heat output could be reduced to as low as 5,000 B.t.u. without adversely affecting operating characteristics, thereby permitting the user to select the desired heat anywhere in the range from 5,000 to 8,000 B.t.u. Mechanical means for accomplishing such selective, controlled variation in heat output provided a number of design problems, which were not adequately solved until the development of the particular adjusting means of the present invention, as will subsequently be described in detail.

THE DRAWINGS Catalytic heaters embodying the features of the present invention are shown in the accompanying drawings, wherein:

FIGURE 1 is an elevational view of a catalytic heater broken away and sectioned for clarity;

FIGURE 2 is a perspective view of the catalytic heater of FIG. 1 with the combustion head removed;

FIGURE 3 is an enlarged plan view of the wick control means of the heater of FIGS. 1 and 2;

FIGURE 4 is a detailed sectional view of the wick control means, taken on line 44 of FIG. 3;

FIGURE 5 is a detailed sectional View of the adjustment means for the wick showing the wick in the low fire position;

FIGURE 6 is a detailed sectional view taken along the line 6-6 of FIGURE 5;

FIGURE 7 is a detailed sectional view taken along the line 77 of FIG. 5;

FIGURE 8 is a detailed sectional view of the wick taken along the line 88 of FIG. 5;

FIGURE 9 is an enlarged perspective view of a spring retainer employed with the wick adjusting means;

FIGURE 10 is an elevational view of a catalytic heater similar to the catalytic heater of FIG. 1 but including some modifications thereof, the view showing the structure broken away and in section for clarity; and

FIGURE 11 is an enlarged elevational view, partly in section showing a modification of the wick adjusting means of FIG. 5.

SUMMARY The means for controllably and selectively varying the heat output of a catalytic heater of this invention is designed for use in combination with a catalytic heater providing a base housing and a combustion head thereabove including an enclosed fuel vapor collection space. The top portion of the combustion head is formed by porous catalytic combustion element means in vapor transfer relation with the collection space. There is also provided tubular connector means extending between the combustion head and the base housing including an outer stationary tube and an inner stationary tube with space therebetween. An unpacked reservoir for liquid fuel is provided Within the base housing, and capillary action wick means extends from the reservoir through the inner tube for liquid fuel transfer therethrough to the vapor collection space.

In accordance with the present invention, lever means is pivotally mounted on the outer tube. The lever means with respect to the pivot mounting thereof provides an inwardly extending actuating arm and an outwardly extending control arm. The actuating arm extends through the wall of the outer tube and across the vapor collection space to a position adjacent the inner tube. The pivot mounting of the lever means includes sealing means providing a substantial seal with the outer tube around the portion of the lever means extending through the wall thereof. There is also provided motion transfer connection means extending from the inner portion of the actuating arm through the inner tube to the wick means for causing the wick means to raise and lower in response to the movements of the lever means. The Wick means is slidable within the inner tube and provides an upper portion extending into the vapor collection space in proportion to the movement of the lever means. The wick means also provides a lower portion sufficiently long to extend substantially to the bottom of the reservoir when the wick means is raised to its maximum extent into the vapor collection space. Preferably, the wick means lower portion is arranged to wipe the bottom of the reservoir in all positions of the wick as it is raised and lowered by the lever means.

In certain preferred embodiments, the pivot ball means is mounted on the lever means between the actuating and control arms, and socket means is fixedly supported in the outer tube for rotatably receiving the ball means while forming a substantial seal therewith. There may also be included motion transfer connection means comprising fork means on the inner end of the actuating arm, and pin means engaging the wick means through vertically extending slot means in the wall of the inner tube. The fork means slidably receives the outer end of the pin means for raising and lowering the pin. Preferably, at least one end of the slot means defines a maximum position of the wick means. For example, the upper end of the slot can serve as a stop for the pin means to limit the maximum upper position of the wick, or the lower end of the slot can serve as a stop to define the lowermost position.

The combination can also include operating means cooperating with a lever control arm for raising and lowering thereof between established maximum upper and lower positions. This may include indicator means adjacent the outer end portion of the operating arm means, which may be indexed to show the raised and lowered position of the wick means relative to the respective positions of the operating arm means outer end portion. More specifically, the operating arm can be formed as a crank arm with the outer end portion thereof being a laterally extending crank portion and terminating in knob means for being grasped by the fingers. The crank portion of the knob means can cooperate with the indicator means to serve as a pointer to position markings provided by the indicator means.

DETAILED DESCRIPTION Referring now to the drawings in greater detail, there is shown in FIGS. 1 and 2 a catalytic heater 20 representing one embodiment of the invention. The heater 20 includes a base or fuel reservoir 22 which is filled with a suitable fluid fuel 24, such as white gasoline, through a filler plug 2-6. A combustion head 28 (FIG. 1) is supported from the base or fuel reservoir 22 by means of a support assembly 30 which is connected to the fuel reservoir 22. A wick 32 extends from the interior of the fuel reservoir 22, through the support assembly 30, into a vapor collection space or chamber 34 within the combustion head 28. The wick 32 includes a generally cylindrical upper end portion 36 and a split lower end portion 37 formed of many downwardly and outwardly extending filaments 38. Liquid fuel is conducted from the filaments 38 of the lower end portion to an upper end portion 36 of the wick by capillary action. The fuel is vaporized, from the exposed upper end portion 36 of the wick 32, in the fuel vapor collection space or chamber 34. The fuel vapors are then burned by a catalytic element 40 of the combustion head 28.

The heater base or fuel reservoir 22 includes a base or bottom wall 42 which is connected to a cylindrical sidewall 44. The cylindrical sidewall 44 is integrally formed with an upper mounting wall 46. The sidewall 44, base wall 42, and upper mounting wall 46 define a clear, unobstructed fuel chamber into which the split lower end portion 37 of the wick 32 extends. The free liquid fuel 24 is unrestrained by packing or baflles. Since the liquid fuel is freely movable within the clear unobstructed fuel reservoir, the liquid fuel will be in direct contact, at all fuel levels and at all wick positions, with the filaments forming lower end portion 37 of the wick. The wick 32 is made sufiiciently long to still extend substantially to the bottom of reservoir 22 when the wick is raised to its maximum extent into vapor collection space 34, as shown in FIG. 1. Preferably lower portion 37 is arranged to wipe reservoir bottom 42 in all positions of the wick as it is raised and lowered. For example, as shown in FIG. 1, the filaments 38 forming the end portion 37 of the wick 32 are radially spread on a bottom or base Wall 45 of the fuel reservoir 22. As the level of the fuel within the fuel reservoir 22 falls, and even with wick 32 fully raised, the end portion 37 remains in direct contact with the free liquid fuel, since the filaments are always positioned against the bottom of the chamber. The end portion 37 of the wick is soaked with fuel, as long as there is fuel in the reservoir 22.

The combustion head 28 includes a generally domeshaped porous catalytic element 40 which forms the upper and side-wall portions for the fuel vapor collection space or chamber 34. The porous catalytic element 40 is made up of an outer screen 50, an inner screen 52, a catalyst layer 53 immediately below the outer screen 50, and a packing filler layer 54 between the catalyst layer 53 and the inner screen 52. The

screens

50 and 52 are preferably formed of a metal wire such as a metal hardware cloth. The catalyst layer 53 is, in the preferred embodiment, made of a thick layer of asbestos burlap impregnated with a platinum catalyst. The thicker backing layer 54 is preferably of a non-combustible fibrous material. Vaporized fuel, from the vapor collection space or chamber 34, flows through the screen 52 and backing 54 and is burned at the catalyst layer 53. Heat, from the burning of the vapor at the catalyst layer 53, is radiated upwardly and outwardly from the combustion element 40. While a dome-shaped combustion element has been used in the preferred embodiment of the invention, combustion elements having cylindrical, conical, and other shapes could be used with the heater.

As described in US. Patent 3,343,586, the bottom surface of the vapor collection space can be formed by a plate 56 of heat conductive metal, such as aluminum or copper. The metal plate 56 will conduct theat into the vapor collection space or chamber 34 from head elements 40 to assist in starting the heater. Also, as described in said patent, a heat insulation mat 60 having a heat reflective upper surface 60a can be provided to assist in maintaining a more uniform high temperature within vapor space 34, promoting vaporization of fuel from the exposed upper portion of the wick.

The combustion head 28 is mounted above the fuel reservoir 22 on a vertical collar 64 which engages the bottom of the insulation pan 60. The insulation pan 60 is releasably held against the top of collar 64 by a threaded flange 65 which is connected to a central support tube which form the outer stationary tube of the support assembly 30. The tube 66 is fastened to the upper portion of the base or fuel reservoir 22 by means of a threaded flange r collar 68 which engages suitable threads at the bottom portion of the support tube 66.

Disposed centrally within the support tube 66 is an inner stationary wick tube 74 in which the wick 32 is slidably mounted. The wick tube '74 extends through an aperture in the upper wall 46 of the base or fuel reservoir 22, as shown in FIG. 1. As also shown in FIGS. and 7, a radially outwardly extending flange member 78 having a collar 78a received on the lower end portion of the wick tube 74. The flange 78 is clamped by the lower end portion of the support tube 66 against the adjacent portion of upper wall 46. As is shown in FIGS. 5 and 7, a pair of upstanding ears or tabs 86 are formed in the flange 78. These ears or tabs engage suitable positioning recesses in the support tube 66 to prevent the wick tube 74 from rotating relative to the support tube 66.

An absorbent plug 88 can be positioned between the upper portion of the wick tube 74 and the inner surface of the support tube 66 as described in said Patent 3,343,586. The plug 88 absorbs moisture which may condense within the vapor collection space or chamber 24 after the heater is extinguished. The moisture will evaporate and the plug 88 will dry out when the heater is lighted. This moisture, which is a product of combustion, might otherwise pass downwardly to the bottom of the annular space 90 between the support tube 66 and the wick tube 74.

The annular space 90 between

tubes

74 and 66 provides vapor pressure relief communication between the interior of head 40 and the interior of reservoir 22. The fibrous plug 88 permits vapor pressure equalization thereacross, or in certain embodients the plug can be omitted altogether. The flange member 78 can be provided with perforations 78b to provide for pressure equalization communication between the lower portion of space 90 and the upper portion of reservoir 22.

The wick 32 can be formed of many different materials and have various cross-sectional shapes while achieving the objects of the present invention. Preferably, however, the wick is formed of non-combustible fibers or filaments 38, such as fiber glass, and has a circular shape in cross-section. The construction of the wick 32 is shown more clearly in FIGS. 6 and 8. It will be noted that the wick has a woven outer tube 94, of a suitable non-combustible material, which encloses tightly packed, vertically extending filaments 38. Wicks of the type described, when saturated with liquid fuel, substantially preclude the transfer of fuel vapors therethrough. The liquid fuel is, therefore, drawn into the bottom portion 37 of the wick and passes upwardly therethrough by capillary action, and is evaporated on the exposed outer surface of the upper portion 36 of the wick, passing into the vapor state within the collection space or chamber 34. While the wick may also be formed of cotton or other combustible material, the exposed upper portion 36 of the wick, when positioned within the vapor collection space or chamber 34, can be burned or charred and thereby cause a reduction or variation in the fuel vaporization rate.

The rate of vaporization of fuel from the upper portion 36 of the wick 32 may be varied by altering the amount of exposed surface area, of the wick, in the vapor collection space or chamber 34. The wick 32 is slidably mdunted within the wick tube 74 so that an adjusting means 100, see FIGS. 2 and 5, may be actuated to extend and retract the upper end portion 36 of the wick into and out of the vapor collection chamber 34. As will subsequently be described, this provides for controlled and selective variation of the heat output. The adjusting means includes a positioning lever pivotally mounted on outer tube 66 and including an outwardly extending control arm portion and an inwardly extending actuating arm portion. The actuating arm portion is in the form of a yoke having a pair of

arms

104 and 106 which extend around the wick tube 74. A pair of forks 122 are integrally formed on the ends of the

arms

104 and 106 and slidably engage the outer ends of a wick pin 108 which extends through the wick 32. The positioning lever 102 is mounted, by a rotatable ball 110, in the side of the support tube 66. The ball 110 is forced into an aperture 112 in the side of the support tube 66 by a retaining spring clip 114 (FIGS. 2, 6 and 9). The retaining spring clip 114 has a pair of spring arms or ears 116 which engage an outer surface of the ball 110 to force the ball into the aperture 112. The ball 110 and aperture 112 provide a mounting around which the positioning lever 102 pivots when the wick 32 is moved relative to the wick tube 74. The ball 110 also acts as a seal for the aperture 112 to prevent vapors or fumes which may form in the annular space 90 from escaping.

Pivoting the lever or yoke 102 vertically at the ball 110, from the position shown in solid lines in FIG. 5 to the upper or lower positions shown in dotted lines, moves the

arms

104 and 106, respectively, upwardly or downwardly relative to the wick tube 74. Motion transfer connection means, which includes said forks 122, also includes a wick pin 108, which extends through the wick 32, simultaneously moves upwardly or downwardly in slots 120 (FIG. 5) in the side of the wick tube 74. It is apparent that the movement of the wick pin 108 causes the upper portion 38 of the wick to be advanced or Withdrawn from the vapor collection chamber 34. The extent to which the wick can be moved is determined by the length of the slots 120, the ends of the slots serving as stops for the pin .108. The wick pin 108 engages an upper end portion 120-a of the slot when the wick is fully extended, as in FIG. 1 and indicated by dotted lines in FIG. 5. Similarly, the wick pin 108 engages a lower end portion 120]) of the slot 120 when the wick is fully retracted.

Referring now to FIGS. 3 and 4, it will be seen that the positioning lever 102 is pivoted by means of an actuator or control assembly 124 which is mounted on the support collar 64 by a bracket 126. The actuator assembly 124 includes a sliding block 128 which slidably engages the outer or control end portion of the positioning arm 102 and is fastened to a crank or actuator arm 130. The crank or actuator arm 130 is turned by a knob 132 connected to the end of a laterally extending crank portion 130a. From a consideration of FTGS. 2, 3 and 4, it is apparent that the crank arm 130 is rotated, by turning the knob 132, the positioning lever or yoke 102 will be pivoted at the ball 110. When the crank or actuator arm 130 is rotated to move the wick from a retracted position to a more extended position, the arm 130 oscillates withinthe oversize aperture 64:! of collar 64. An indicator plate 134 can be mounted on the exterior surface of the actuator bracket 126. The indicator plate 134 has indicia indicating the start or high heat position, the medium heat position and a low heat position. An off position can also be designated, or may be omitted.

For example, as the knob or handle 132 of the crank arm 130 is rotated to a position adjacent the start or high heat indicia, as shown in FIG. 1, the wick 32 will be extended to maximize the exposed surface area of the Wick in the vapor collection chamber and, therefore, maximize the heat output of the heater. As the actuator handle or knob 132 is moved from the high heat position to a lower heat position, such as the low heat position shown in solid lines in FIG. 5, the wick will be gradually withdrawn from the vapor collection chamber 35 to reduce the exposed surface area of the wick and the heat output from the heater. By moving the actuator knob or handle 132 to the off position, as shown in FIGS. 1 and 2, the wick 32 can be almost completely retracted into the upper end of the wick tube 74. This will tend to extinguish the catalytic heater. However, this feature is optional, since it will usually be desired to provide a removable snuffer cover fitting closely over head 28 for rapid extinguishment of the heater.

As shown in FIGS. 1-4, a latch or stop member 136 can extend outwardly from the indicator plate 134 of the actuator bracket 126. The latch or stop member can be forced toward this outer position by a leaf spring 138 which is integrally formed with the stop or latch member 136. As shown, latch 136 serves as a stop for the low fire position of handle 132 and arm portion 130a. If the latch member 136 is pressed inwardly, against the leaf spring 138, the actuator crank 130 can be released so that the crank can be moved to an off position. The latch member 136 prevents the crank 130 from being inadvertently moved to the off position.

At the high heat position, with a three-fourth inch diameter wick, it has been found that an extension of one and one-eighth inches of the wick into the chamber 34 will give a vaporization rate sufiicient to give a heater output of about 5,000 B.t.u. per hour. If the Wick is withdrawn into the wick tube 74, by moving the actuator handle or knob 132 to the medium heat position, the catalytic heater 20 will radiate approximately 4,000 B.t.u. per hour with about seven-eighths of an inch of the wick extending into the vapor collection chamber. When the actuator knob 132 is moved to the low heat position, about one-half of an inch of the wick will extend into the vapor collection chamber and the heater 20 will give off approximately 2,900 B.t.u. per hour. By using larger or smaller diameter wicks, which can be extended for varying predetermined distances within the vapor collection chamber 34, it will be apparent that almost any desired heater output can be obtained.

In FIGS. 10 and 11, a modified heater is illustrated. Corresponding parts having been given the same numbers except that the numbers have been primed.

Referring now to FIG. 11, the positioning arm 102' is attached, as by press fitting, to the ball 110'. A collar 200 is located at the junction between positioning arm 102' and the U-shaped segment of the yoke, abutting the inner side of the ball 110' and limiting its location on the positioning arm. A ball socket 201 is rigidly attached to the support tube 66 and forms a vapor seal therewith. The ball socket 201 is externally threaded, as at 202. After the ball 110' is seated into the ball socket 201, a gasket or washer 203 is placed over the positioning arm and forced against the ball socket by means of a cap 204 threaded onto the external threads 202 of the socket 201. This advantageous arrangement provides an improved vapor seal, between the adjusting means and outer tube 66'. Such a vapor seal is advantageous to prevent the escape of fuel vapors from annular space 90'.

As the positioning arm 102 is rotated about the center of the ball 110, the yoke arms 104 and 106' Will raise and lower the pin 108' which extends through the wick 32', thereby adjusting the amount by which the Wick extends into the vaporization chamber 34. The upper edge 120a of the slots 120 limit the exposure of the wick in the combustion chamber 16. In addition, the lower edges 12% of the slots 120' define a limit to which the wick can be retracted from the vaporization chamber i t the wick tube 74. This corresponds with the low position. The lower portion 37' of wick 32 wipes against the reservoir bottom 42' in all wick positions. In this embodiment, no olf position is provided, and a snuifer cover 205 having a handle 206 can be used to extinguish the heater. A protective hood or canopy can be provided for enclosing head 40' during operation of the heater, as described in Patent 3,343,586.

While in the foregoing specification this invention has been described in relation to certain specific embodiments thereof and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied Without departing from the basic principles of the invention.

We claim:

1. In combination with a catalytic heater of the kind providing a base housing, a combustion head thereabove including an enclosed fuel vapor collection space, the top portion of said head being formed by porous catalytic combustion element means in vapor transfer relation with said collection space, tubular connector means extending between said combustion head and said base housing including an outer stationary tube an inner stationary tube with space therebetween, an unpacked reservoir for liquid fuel provided within said base housing, and capillary action wick means extending from said reservoir through said inner tube for liquid fuel transfer therethrough to said vapor collection space, means for controllably and selectively varying the heat output of said heater comprising:

(a) lever means pivotally mounted on said outer tube,

said lever means with respect to the pivot mounting thereof providing an inwardly extending actuating arm and an outwardly extending control arm,

said actuating arm extending through the wall of said outer tube and across said vapor collection space to a position adjacent said inner tube,

the pivot mounting of said lever means including sealing means providing a substantial vapor seal with said outer tube around the portion of said lever means extending through the wall thereof; and

(b) motion transfer connection means extending from the inner portion of said actuating arm through said inner tube to said wick means for causing said wick means to raise and lower in response to the movements of said lever means;

said wick means being slidable within said inner tube and providing an upper portion extending into said vapor collection space in proportion to the movement of said lever means, and said wick means also providing a lower portion sufficiently long to extend substantially to the bottom of said reservoir when said wick means is raised to its maximum extent into said vapor collection space.

2. The combination of claim 1 in which said wick means lower portion wipes the bottom of said reservoir in all positions of said wick means as it is raised and lowered by said lever means.

3. The combination of claim 1 in which pivot-ball means is mounted on said lever means between said actuating and control arms to provide said pivot mounting, and socket means fixedly supported in said outer tube is provided for rotatably receiving said ball means while forming a substantial vapor seal therewith.

4. The combination of claim 1 in which said motion transfer connection means comprises fork means on the inner end of said actuating arm, and pin means engaging said wick means through vertically extending slot means in the wall of said inner tube, said fork means slidably receiving an outer end of said pin means for raising and lowering said pin.

5. The combination of claim 4 in which at least one end of said slot means defines a maximum position of said wick means.

6. The combination of claim 1 in which said means for varying the heat output also includes operating means cooperating with said lever control arm for raising and lowering thereof between pro-established maximum upper and lower positions.

7. The combination of claim 6 in which there is also provided indicator means adjacent the outer end portion of said operating arm means and being indexed to show the raised and lowered positions of said wick means relative to the respective positions of said operating arm means outer end portion.

8. The combination of claim 7 in which said operating arm means is in the form of a crank arm with the'said outer end portion thereof being a laterally extending crank portion and terminating in knob means for being grasped by the fingers, said crank portion and said knob means cooperating with said indicator means to serve as a pointer to position markings provided by said indicator means.

9. In combination with a catalytic heater of the kind providing a base housing, a combustion head thereabove including an enclosed fuel vapor collection space, the top portion of said head being formed by porous catalytic combustion element means in vapor transfer relation with said collection space, tubular connector means extending between said combustion head and said base housing including an outer stationary tube and an inner stationary tube with space therebetween, an unpacked reservoir for liquid fuel provided within said base housing, and capillary action wick means extending from said reservoir through said inner tube to said vapor collection space, said wick means providing a cross-section substantially filling said inner tube for liquid fuel transfer therethrough while being slidable with said inner tube, said space between said tubes extending substantially from said base housing to said combustion head and being subject to fuel vapor admission, means for controllably and selectively varying the heat output of said heater comprising:

(a) lever means pivotally mounted on said outer tube,

said actuating arm extending through the wall of said outer tube and across said vapor collection space to a position adjacent said inner tube;

said wick means being slidable within said inner tube and providing an upper portion extending into said vapor collection space in proportion to the movement of said lever means, and said wick means also providing a lower portion wiping the bottom of said reservoir in all positions of said wick means as it is raised and lowered by said lever means.

10. The combination of claim 9 in which pivot-ball means is mounted on said lever means between said actuating and control arms to provide said pivot mounting, and socket means fixedly supported in said outer tube is provided for rotatably receiving said ball means while forming a substantial vapor seal therewith.

11. The combination of claim 9 in which said motion transfer connection means comprises fork means on the inner end of said actuating arm, and pin means engaging staid wick means through vertically extending slot means in the wall of said inner tube, said fork means slidably receiving an outer end of said pin means for raising and lowering said pin.

12. The combination of claim 11 in which the upper and lower ends of said slot means respectively define the maximum raised and lowered portions of said wick means by respectively limiting the upward and downward movement of said pin means.

13. The combination of claim 9 in which said means for varying the heat output also includes operating means cooperating with said lever control arm for raising and lowering thereof between preestablished maximum upper and lower positions.

14. The combination of claim 13 in which there is also provided indicator means adjacent the outer end portion of said operating arm means and being indexed to show the raised and lowered positions of said wick means relative to the respective positions of said operating arm means outer end portion.

15. The combination of claim 14 in which said operating arm means is in the form of a crank arm with the said outer end portion thereof being a laterally extending crank portion and terminating in knob means for being grasped by the fingers, said crank portion and said knob means cooperating with said indicator means.

16. The combination of claim 9 in which said motion transfer connection means comprises yoke means on the inner end of said arm, and yoke means providing a pair of fork means disposed on opposite sides of said inner tube, said inner tube providing a pair of oppositely disposed vertically extending slot means respectively adjacent each of said fork means, pin means extending through said wick means and providing outwardly projecting ends extending through said slot means for sliding engagement with said forkmeans for cooperation in raising and lowering said wick means.

References Cited UNITED STATES PATENTS 92,695 7/ 1869 Blackman 431-315 101,427 4/1870 Cade 431-315 937,362 10/1909 Coombs 431-315 967,925 8/1910 Ives 431-315 1,128,740 2/1915 Wilcox 431-17 1,347, 63 1 7/ 1920 Herck 431-258 3,042,108 7/1962 Boij et al. 431--323 3,343,586 9/ 1967 Berchtold et al 431-241 CHARLES I. MYHRE, Primary Examiner US. Cl. X.R.