US2506192A - Fan regulator - Google Patents

Description

R. W. BEC KETT May 2, 1950 FAN REGULATOR 2 Sheets-Sheet 1 Filed Aug. 7, 1947 HVVENUR. W Beckett I Reginald BY R. w. BEcKl-:TT

v FAN REGULATOR May 2, 195o 2 Sheets-Sheet 2 Filed Aug. '7, 1947 INVENTOR. Regina/lol W .Beckett BY Patented May 2, 1950 UNITED STATES PATENT OFFICE 11 Claims.

This invention relates to oil burners and has particular reference to oil burners of the pressure atomizing type in which fuel oil is discharged under pressure through a small orifice or nozzle into a combustion chamber and is burned while suspended in the combustion air that is supplied by a power driven fan, the air being proportionedr to the oil to obtain eiilcient combustion.

Oil burners of the type involved in the present invention have been highly developed and are presently in common use in large numbers. There are, however, a number of desirable improvements that are continuously being sought. Primarily it is desirable to reduce the cost of manufacture of these burners so as to make them more readily available to the public at large. Other improvements needed are along the lines of greater eiiciency, quieter operation, and safety.

It is therefore the principal object of the present invention to provide a generally improved oil burner construction of the pressure atomizing type in which numerous advantageous features of construction and arrangements of parts have been incorporated t obtain economic manufacture and operation, relatively silent operation, and safety.

Economy is obtained by unique design features which facilitate assembly with a minimum of machining of parts and without special skill or the necessity for the use of special tools, jigs, and fixtures. Reduced cost is also obtained by the elimination of parts to simplify the design of the burner and the assembly and installation thereof.

Noise reduction during operation of the burner is obtained through improved mounting means for supporting the so-called power unit of the burner, which comprises the electric drive motor and the fan and the fuel pump actuated thereby. Additional noise reduction is obtained through improved design of the air induction system and the provision of a balanced structure so supported as to minimize vibration and oscillation during operation.

Safety is enhanced by the use of a new type of electronic control system (not of the present invention) which includes a light or flame responsive phototube that is so mounted in the burner as to be enclosed and protected by the burner structure and continuously cooled by incoming combustion air, the phototube being connected by electrical wiring which also is wholly enclosed within the burner structure.

Other objects and advantages will become apparent from the following detailed description of a burner embodying the principles of the present invention, such description being made in connection with the accompanying drawing forming a part of this specication.

In the drawings:

Figure 1 is a side elevational view partly in section and with parts broken away and removed showing the oil burner structure;

Fig. 2 is a plan View of one of the supporting and spacing blocks of the pedestal, this view beingy taken approximately on the line indicated at 2 2 of Fig. 1;

Fig. 3 is a sectional detail through one corner of the supporting block of Fig. 2 being taken substantially on the line indicated at 3--3 of Fig. 2 and enlarged with respect to that gure;

Fig. 4 is a fragmentary front end view looking into the air tube of the burner, this view being taken substantially along the line indicated at 4--4 of Fig. 1;

Fig. 5 is a schematic wiring diagram showing electrical connections associated with the control for the oil burner;

Fig. 6 is a fragmentary front view of the burner, partly in section, showing the air induction hood, other parts of the burner being broken away and removed;

Fig.l'7 is a fragmentary horizontal sectional detail taken substantially on the line 'lof Fig. 6 and enlarged With respect to that figure;

Fig. k8 is a vertical sectional detail through the air induction hood of the burner, this view being taken substantially on the line indicated at 8-8 of Fig. 6 and enlarged with respect to that figure;

Fig. 9 is a transverse sectional detail taken Substantially on the line 9 9 of Fig. l, parts of the burner being broken away and removed;

FigflO is a transverse sectional detail taken substantially on the line llli0 of Figjl;

Fig. 11 is a detail View partly in section and with partsbroken away taken throughthe bellshaped member which mounts the fuel pump on the end of the electric drive motor; and

Fig. 12 is a fragmentary detail, partly in section, taken substantially on the line indicated at |2-I2 of Fig. 6. Y

The oil burner of the present invention is generally of the type disclosed in my prior United States Patent No. 2,310,274 and the patents referred to therein, the present design being particularly suited for use at higher oil rates. Referring now to the drawings by numerals of reference which indicate like parts throughout the several views, the burner is seen to comprise an upright housing structure of generally ovate form having spaced substantially parallel front and rear walls l and 2 respectively, substantially parallel side walls S and 4, which join and are narrower than the front and rear walls, and a curved top Wall 5. The housing is of cast metal such as iron or aluminum and includes a bottom 6 which is integral with the front and rear walls and is connected into the side walls 3 and 4 by curved wall portions.

Support shells In each corner of the spacing shell is an integral column lll which projects below the level of the bottom edges Il of the shell so as to provide depending foot portions l2 received in interlocking relation in mating recesses formed in the top of the base 'l or in the top of the next lower spacing shell. In the shells 9 upper ends of the columns lll are disposed below the level of the upper edge i6 so as to provide the mating sockets in the corners for receiving the foot portions I2 of the surmounting spacing shell or bleek. The foot portions l2 of the columns of the Spaing shell 8 bear on the upper ends i5 of the columns of the spacing shell 9 so that the weightv of the burner isr carried largely by the columns of the shells. The base l is formed with thiol; sectioned bosses I1 having at tops recessed below the level of the square top of the base and which serve as footings for the spacing shell columns IU, the latter intertting in the square base to permit relative tur-ning.

The upper shell 8 differs slightly from the spacing shell 9 in that the columns I0 thereof extend upwardly above the level of the top edge I6 of the side walls providing lugs i3 which interiit in mating recesses formed in the corners of ay square socket in the bottom 3 of the housing. The intertting feet and sockets on the ends of the columns lil prevent relative turning of the spacing shells on one another, on the base l, and in the housing bottom 6 so that the housing structure is maintained in pre-determined nonrotative position relative to the base. Although only two shells are shown it is contemplated to use an additional number of the shells 8 if greater height is desired, or to lower the housing, the spacing shell El may be eliminated or the burner can be mounted directly on the base l.V

The housing is secured to the base by a vertical stp-ud or through bolt I9 the upper end of which is threadedly secured in the housing bottom 6 and the lower end of which extends downwardly through and is centered in an opening in platform portion 2B of the base. A nut 2l is tightened against the underside of the base platform to hold the assembly together.

An electric motor 22 supplies the energy for driving squirrel cage fan or sirocco type blower 23 which is received in a chamber 24 formed in the upper portion of the housing. The fan, inserted into the blower chamber through a large diameter opening 3l provided in the rear wall 2 of the housing, is secured on one end 25 (Fig. l) of the motor shaft.

Motor shaft portion 23 (Figs. l0 and ll) which projects from the other or flat end 21 of the motor is surrounded by a` bell-shaped support member 23 that is secured to the motor end 2l by diametrically located cap screws, one of which is indicated at 29. The bell member 28 is formed with an offset circular flange 30 which embraces the motor end 2l and provides a circumferentially extending internal shoulder against which the motor end is seated and located.

Ihe small end of the bell member 23 is formed with a centrally located integral cylindrical sleeve 32 having an internal cylindrical bore 33 that is substantially co-axial to the rotational axis of the motor shaft. Received within the bore or socket 33 is a mating cylindrical plug member 34 formed on a fuel oil pump 35.

The pump plug 34 contains a central journal for pump shaft 36 which is thus disposed in end to end cofaxial relation to the motor shaft end 26. A flexible drive coupling connects the shaft ends, one coupling part 31 being secured by a set screw on the motor shaftv end 26 and another coupling part 33 being secured, also by a set screw, on pump shaft 36. A resilient deformable element 3Q is interposed between the coupling parts 3l and 38 to transmit the torque while providing for slight misalignment or displacement ofl the shafts. One or more set screws 40 threaded through the bell sleeve 32 are engaged in detents in the pump plug 34 to lock. the latter in the bell member sleeve and to retain the pump in pre-determined upright position.

The motor 22, together with the fan 23 and the pump 35 secured on opposite ends thereof, are collectively referred to and comprise a removable power unit. This unit operates the oil burner, the pump feeding oil under pressure and the fan supplying combustion air. It is therefore extremely desirable to. be able to replace the power unit should a failure occur in either the pump fan or motor so that the oil burner can be continued in ser-vice with a minimum of delay or interruption.

Resilient suspension In the present burner design a unique suspension means is provided for the power unit. Reference is made to my copending application for patent Serial No. 118,313, filed September 28, 1949, for Motor suspension for oil burners and the like in which this feature is described claimed. A bracket 42 having a transversely curved body portion 43 is concave on its underside so as to nt over and partially embrace the top of the motor. The body of the bracket .is generally concentric to4 the curvature of the motor, the latter being suspended in spaced re.- lation underneath the bracket as will later appear. At one end of the curved body 43 the bracket is formed with an integral depending flange 44 which is disposed atwise against the rear wall 2 of the housing structure and is secured to the latter over the opening 3l by cap screws 45. The bracket flange 44 thus closes the relatively large rear opening in the housing wall 2 through which the fan 23 is inserted into the fan chamber 24, the bracket flange having a rel-y atively small opening 46 which closely surrounds the motor shaft end 25.

Along opposite sides of the bracket at thelower edges of the arcuate or curved body 43 are horizontal portions or lateral extensions 41 which terminate in depending flanges 48. Rubber tension type suspension members 50 are secured by bolts I to the underside of the lateral bracket extensions at the front and rear. ends of the latter, the bolts being threaded into metal elements embedded in the rubber of the suspension members.

One pair of the resilient rubber members 50 are attached by bolts 52 to half straps 53 and 54 which cooperatively embrace the motor 22, the bolts 52 passing through radial ears 55 on the ends of the half straps, and being threaded into metal elements embedded in the rubber of the suspensionv members. The half strap 53 passes over the top of the forward portion of the motor and is disposed underneath the curved body portion 43 of the bracket, while the half strap `54 extends underneath the forward portion of the motor to support the latter. The bolts 52 draw the half straps tightly about the frame of the motor so as to clamp the motor in place and and prevent longitudinal movement thereof. The other pair of the resilient rubber suspension members l5l), which depend from portions of the bracket extensions 41 that project rearwardly of the curved body portion 43 of the bracket, are secured by bolts 56, threaded into embedded metal elements, to diametrically disposed integral ears 51 which extend outwardly from opposite sides of the bell-shaped support member 28.

Thus the power unit is resiliently suspended from the bracket 42 by a plurality of resilient rubber members in tension. Extremely quiet burner operation results from this type of mount and the attachment of the resilient elements 50 to different zones along the length of the motor minimizes lateral displacement of the motor and serves to hold the motor in pre-determined relative position with respect to the burner housing structure.

In manufacturing the burner, the motor, bell member, pump and fan are assembled together on the bracket 42 and this sub-assembly is then mounted as a unit on the housing simply by inserting the fan into the chamber 24 through the opening 3| in the housing wall 2 and securing the bracket flange 44 in place by the cap screws 45. The arrangement of the power unit and the attaching bracket as a sub-assembly facilitates economical mass production, the parts being interchangeable, and also permits replacement of the power unit in the field should it become desirable to retain the burner in continuous service while repairs are being made on the motor or fuel pump.

Air induction and control Airis drawn into the fan chamber 24 through a large inwardly tapered opening formed in the front wall I of the housing and having circular converging walls 58 to provide a smooth nonturbulent inflow of air. A circular flange 59 of generally conical shape is integrally formed on the inside of the front wall of the housing and extends around the opening and into the fan chamber 24, forming part of the tapered inlet wall 58. The inner edge of the flange I59 is disposed closely adjacent the open inlet end of the fan 23, there being a running fit between the parts to permit rotation of the fan and such vibration as occurs in normal use without contact between the fan and the flange.

Disposed against the outside of the front Wall 6 I of the housing and over the air inlet opening into the fan chamber so as to control the ow of air through such opening, is a hood 60 which may be of cast metal. The construction and mounting of this hood on the burner is one of the important features of the present invention since it is .very economical to manufacture, assemble, and service, and yet provides for accurate control of air flow into and through the burner.

The hood has an inclined front wall 62 spaced from the front wall I of the housing structure by a curved top wall 63 and side walls 64. Across the bottom the hood is open to permit the inflow of air under the control of a sheet metal gate B5 pivotally mounted off center for turning movement about a horizontal axis. The gate is supported on pins 66 that are threaded through aligned openings in bottom portions of the side walls 54, the pins being held against turning by lock nuts S1. Reduced diameter pivot ends of the pins 55 are received in openings in upstanding ears G8 that are formed or welded on the opposite ends of the gate 65. The folded overportion along the rear marginal edge of the gate, weights or counter-balances the latter so that the gate can be moved -upwardly to open position by relatively small force such as that of inflowing air.

The rear edges of the curved top wall 63 and the side wall 64 of the hood are directed toward an integral outstanding rib 69 which is formed on or characters the front wall I of the housing and has the same contour or outline shape as the edges of the hood walls. The hood does not make peripheral contact with the housing rib 69 but is spaced therefrom by three integral bosses or raised portions 1I] that are integrally formed on the edges of the hood walls in spaced relation to one another. One of the bosses is at the center of the top wall 63 and the other two are at the bottoms of the side walls 64, providing a three-point contact for the hood against the housing. Cap screws or bolts 12 pass through openings in ears 13 provided one on each side of the hood and are threaded into the front wall l of' the housing structure. Each of the cap screws 12 is located between the top spacing boss and,A one of the side spacing bosses so that the hood is held by three-point contact tightly agains the housing structure, there being a clearance 14 between the edges of the hood walls and the rib 69 on the front wall I of the housing around substantially the entire extent of the hood except for the three-points of contact between the bosses 1D and the housing rib. Although the spacing bosses 10 are shown to be integral with the walls of the hood 60 they may, in the alternative, be formed on the rib B9 of the housing or the rib 69 may be eliminated and the spacing bosses formed either on the front wall of the housing or on the edges of the hood walls.

vThe hood and housing combination of the present invention can be readily assembled even though made by a casting process. The clearance 14 provides for slight irregularities such as might be caused by shrinkage and casting defects and the use of a pair of attaching bolts or screws in combination with the three-point contact between the hood and the housing insures a rigid assembly without requiring special machining of the parts other than drilling and tapping the housing for the screws or bolts 12.

in adjusting the burner for different ou ratesv land the terminal |08 therein. safety combustion control mechanism for` govand is disconnected from the fuel pump 35 when it is desired to remove the fuel conduit toured to correspond to the curvature of the bottom of the air chamber of the housing and is apertured to receive an upstanding bolt |02 that extends upwardly 'through a hole in the bottom 6 of the burner housing. A nut |03 on the bolt |02 is tightened down against the base IDI of the bracket to secure the latter in place, the bolt having a square or non-circular head |04 that is received in a mating recess formed in the underside of the housing bottom 6 so as to prevent turning of the bolt when tightening or loosening the nut |03.

An integral finger which extends inwardly from one of the walls of the uppermost spacing block 8 engages the head |04 of the bolt to prevent the bolt from dropping out of the hole provided therefor in the housing bottom 6. Thus the bolt is retained in place when the nut |03 is removed for withdrawal of the ignition electrode and fuel conduit assembly. This particular arrangement for retaining the bracket locking bolt |02 reduces the assembly cost of the burner, since machining of the casting which constitutes the burner housing is avoided. Furthermore, the bolt |02 can be readily replaced should it be broken or damaged.

Electrical control and wiring Control of the electrical current to energize the motor and the transformer is effected by 'means such as the electronicv combustion safety system manufactured by Minneapolis-Honeywell Regulator Company and known as the Rl'llA relay and the series controller. The side wall 4 of the burner housing is formed to receive a junction box |08 to which is mounted the control mechanism (not shown). Electrical leads or wires III and II2 from the motor 22 are contained in an insulated conduit |01 which runs through an opening in the rear wall of the housing and through an internal chamber of the housing, the leads being brought into the junction box and connected to terminals I 08 and |09. Leads orwires i I4 and I I5 from the transformer |00 are also contained in aninsulated conductor or conductors which extend through `to the system through line conductors L-I and L--2 which are brought into the junction box |06 and connected respectively to terminal ||9 The relay of the erning the burner operation is contained in a metal box which lits over the junction box |06. Electrical connection is made with the various terminals in the latter by captive screws or other means not shown. Besides the motor and transformer, other devices such as the above mentioned series 10 controller indicated at iIEi, and a limit control indicated at I Il'may be connected into the control mechanism through the junction box |05, the leads or wires from these de- Lvices being attached 4to terminals in the junction .l0 box that are contacted by the captive screws of the relay box.A

Phototube mount tablished within a pre-determined time interval.

Establishment of a lasting name, however, stimulates the photocell to effect ignition cut-olf and to shut out the heater of the safety switch so that burner operation continues.

The photoelectric cell or phototube can be located in any suitable .position where it is exposed to the light rays emanating from the burner name. As a particularly advantageous location the present invention provides means for mounting the photocell II8 in the air tube 85, in a container |25 which faces toward the open mouth of the burner head 00. The container is supported on a bracket I 20 which is slidable to different positions along the rigid fuel conduit 89.

A flexible electric conductor 2| is connected tothe anode of the photocell ||8 through the rear of the casing |25 and extends through the air tube and the air chamber in the bottom of the housing, thence through the aforesaid internal vchamber of the housing and into the junction box |06 where it is connected to terminal |22. The phototube cathode is grounded to the burner housing structure through the adjustable bracket |20 and the ignition electrode and fuel conduit assembly. Thus the photocell conductor is contained wholly within the housing structure of the oil burner so as to be protected against displacement and damage. Furthermore the photocell. located in the air tube adjacent the rear en d thereof is customarily cooled by the air flowing thereover while the burner is in operation.

Although the photocell mount is shown closely adjacent the supporting bracket 9| the bracket |20 maybe moved forwardly on the conduit 819 to a position vin which the photocell is ycloser to the burner head. The particular location of the -photocell along the length of the fuel conduit 89 supportingv the same may be variedto suit the particular conditionsv and requirements of any one burner installation. For example, the air tube may be considerably longerthan shown and in lengthy air tubes it may be desirable to move the photocell forwardly, relatively closer to the burner head and away from the ignition electrode bracket 0I. A Set screw |23 isprovided in the photocell bracket |20 to retain the latter in adjusted position onthe rigid` oil conduit so that the bracket does Anot become displaced 'upon removal of the assembly in service. Reference is made to my copending application for patent Serial No. 149,550, filed March 14, 1950, for Fluid fuel burner which describes and claims certain of the above mentioned features.

The principles of the present invention may be utilized in various ways. numerous modifications and alterations being contemplated, substitution of parts and changes in construction being resorted to as desired, it being understood that the embodiment shown in the drawings and described above is given merely for purposes of explanation and illustration without intending to limit the scope of the claims to the specic details disclosed.

What I claim is:

l. In an oil burner of the pressure atomizng type, a housing structure dening a fan chamber and having one wall formed With an air inlet opening, an assembly comprising a removable open bottomed hood disposed against said wall over said air inlet opening to control the ow of air into the fan chamber, a gate disposed across the open bottom of the hood, means carried by the hood and supporting the gate for shiftable movement about a substantially hori- Zontal axis to regulate the size of the hood opening and governthe fiovv of air into the hood, a control rod supported by the hood and extending through the latter, a portion of said rod being disposed vto engage the gate and limit the pivoting thereof, and means for retaining the rod in different positions of adjustment, said hood assembly, including the pivoted gate and the adjustable rod, beine,r removable as a unit from said wall of the housing structure to provide access to the fan chamber through said wall opening.

2. In a pressure atomizing oil burner having a supporting housing structure dening an air inlet opening, a movable gate for controlling the flow of air into the burner through said opening, a rod mounted in the supporting structure for turning movement, said rod having an angularly disposed portion on one end engageable with the gate to limit the movement of the latter, and means on the supporting structure providing a shoulder engageable with the angu ,l

larly disposed portion of the rod to limit the turning movement of the latter, said shoulder being disposed to engage the rod upon movement of the latter to that adjustment providing mini mum opening of the air gate.

3. In combination in an oil burner, a housing having a fan chamber and a concave open sided hood unit disposed against the housing and removable therefrom, the hood unit having walls with edges directed toward the housing, means securing the hood unit on the housing for facile removal therefrom, and means spacing the major portion of the length of the edges of the hood from the housing to accommodate slight irregularities in the hood unit and the housing.

4, In combination in an oil burner, a housing having a fan chamber and a concave open sided hood unit disposed against the housing and ren movable therefrom, the hood unit having Walls with edges directed toward the housing, ears on the hood unit, means interconnecting the ears and the housing to secure the hood unit on the housing for facile removal therefrom, and means spacing the major portion of the length of the edges of the hood from the housing to accommodate slight irregularities in the hood unit and the housing.

5. In combination in an oil burner, a housing having a fan chamber and a concave open sided jhood unit disposed against the housing and removable therefrom, the hood unit having walls with edges directed toward the housing, means securing the hood unit on the housing for facile removal therefrom, means spacing the major portion of the length of the edges of the hood l 12 from the housing to accommodate slight irregularities in the hood unit and the housing, and the hood unit including adjustable gate means wholly supported by the hood walls within the concavity of the hood.

6. vIn combination in an cil burner, a housing having a fan chamber and a concave open sided hood unit disposed against the housing and removable therefrom, the hood unit having walls with edges directed toward the housing, means securing the hood unit on the housing for facile removal therefrom, and means interposed between the hood and the housing at spaced intervals to hold the Wall edges away from the housing and maintain a clearance therebetween.

7. In combination in an oil burner, a housing having a fan chamber and a concave open sided hood disposed against the housing and removable therefrom, the hood interior compris! ing a chamber substantially closed on one side by the housing and communicating with the ian chamber through an opening in the housing, a gate pivotally mounted in the hood chamber and movable to different open positions for regulating the flow of air through the hood chamber, a rod wholly supported by the hood and extending into the hood chamber for controlling the movement of the gate, said rod being mounted to swing over an arcuate path to different positions of adjustment in varying the open positions of the gate, means on the hood in the pathof the rod to engage the latter and serve as an indexing stop therefor, and means securing the hood on the housing for facile removal for access to the gate and the control means through the open side of the hood for repair and replacement.

8, In an oil burner, a housing having walls dening a fan chamber and an opening into the chamber through one of the walls, a hood and means mounting the hood against said one Wall for facile removal and replacement in servicing and assembling the burner, the hood and housing providing an air chamber in communication with the fan chamber through the opening, an opening across the bottom of the hood through which air flows upwardly in entering the air chamber, a closure gate disposed across the bottom opening, means mounting the gate for turning movement about a substantially horizontal axis between open and closed positions, a control rod, and means mounting the rod to turn about a substantially vertical axis, the rod being disposed within the hood and including an element engageable in diierent positions with the gate to vary the opening movement of the latter, the gate and rod mounting means being carried wholly by the hood for removal and replacement therewith as a unit.

9. In an oil burner, a housing having walls defining a fan chamber and an opening into the chamber through one of the walls, a motor and fuel pump unit mounted on another wall of the housing, a fan in the chamber and means drivingly connecting the fan to the motor, a one piece hood and means mounting the hood against said one Wall for facile removal and replacement in servicing and assembling the burner, the hood and housing providing an air chamber in communication with the fan chamber through the opening, an opening across the bottom of the hood through which air flows upwardly in entering the air chamber, a closure gate disposed across the bottom opening, means mounting the gate for turning movement about a substantially horizontal axis between open and closed posi.-

tions, a control rod, and means mounting the rod to turn about a substantially vertical axis, the rod being disposed Within the hood and including an element engageable in different positions with the gate to vary the opening movement of the latter, the gate and rod mounting means being carried wholly by the hood for removal and replacement therewith as a unit, and independently of the motor and fuel pump unit.

10. For use in an oil burner structure having a fan housing with an air inlet opening in one wall, an air control unit comprising in combination a concave hood having an open side, means to attach the hood to the housing over the inlet opening for facile removal and replacement of the unit with the open side of the hood toward the housing Wall to provide an air chamber interiorly of the hood in communication with the fan housing interior through the air inlet opening, a gate and hood supported means mounting the gate in the hood for pivotal movement about one axis, a rod extending through the hood and journaled in the hood for turning movement about another axis, an element in the hood air chamber movable with the rod and engageable with the gate to limit the pivotal movement of the gate, means on the rod exteriorly of Ithe hood chamber for manually manipulating the rod to different positions in adjusting the element to vary the gate movement, and means carried by the hood for holding the rod in adjusted position.

11. For use in an oil burner structure having a fan housing with an air inlet opening in one wall, an air control unit comprising in combination a concave hood having an open side, and an open bottom, means to attach the unit to the housing with the open side of the hood over the inlet opening, a gate and means carried wholly by the hood mounting the gate across the open bottom of the hood for pivotal movement about a substantially horizontal axis between a normal gravity maintained closed position in which the gate is substantially horizontal across the hood bottom and an air pressure maintained open position displaced from the closed position, a rod extending through the hood, means carried wholly by the hood mounting the rod for movement to different positions, an element movable with the rod and engageable with the gate in the different positions of the rod to vary the open displaced position of the gate, and means carried by the rod exteriorly of the hood for manually manipulating the rod to different positions in adjusting the unit to Vary the air admission to the burner, the atta-ching means being arranged for facile mounting and demounting of the unit on the housing in assembling and servicing the burner.

REGINAID W. BECKE'IT.

REFERENCES CITED The following references are of record in the

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