US2504174A - High-low control for pot-type burners - Google Patents

Description

April 18, 1950 G. D. BOWER 2,504,174

HIGH-LOW CONTROL FOR POT-TYPE BURNERS Filed Dec. 17, 1943 4 Sheets-Sheet l fir TO ave 45.

I i I l April 18, 1950 Filed Dec. 17, 1943 G. D. BOWER HIGH-LOW CONTROL FOR POT-TYPE BURNERS 4 Sheets-Sheet 3- GEORGE pflow-6R,

April 18, 1950 e. D. BOWER HIGH-LOW CONTROL FOR POT -TYPE BURNERS 4 Sheets-Sheet 4.

Filed Dec. 1'7, 1943 a k w 6 L/ W HQ Patented Apr. 18, 1950 HIGH-LOW CONTROL FOR POT-TYPE BURNERS George D. Bower, University City, Mo., assignor, by mesne assignments, to Missouri Automatic Control Corporation, a corporation of Missouri Application December 17, 1943, Serial No. 514,587

13 Claims.

The present invention relates to a liquid fuel burner, and a control therefor.

An object of the invention is to provide a fuel feeding means which will feed fuel to a burner at a definite rate regardless of the consistency of the fuel. More particularly, this object is to provide a fuel feeding means which feeds fuel as a function of a pumping mechanism, rather than as a function of the force of gravity.

Another object is to provide a means for adjustment of the rate of fuel feed which is easily and quickly changed and which may be changed without the use of tools.

A further object is to provide a two stage or high-low control which may be controlled by any two wire thermostat.

A further object is to provide a control that will shift from low rate to high rate as a function of time and trend.

A further object is to provide a control appiicable to pot type burners which maintains a circulating fan for the combustion air in operation for a period after the fuel feed has stopped, so as to burn out or scavenge any fuel left in the burner.

A further object is to provide a readily operable adjustment for the high-low mechanism.

A further object is to provide a pot type burner control without floats or needle valves.

A further object is to provide a drip bucket safety mechanism wherein the drip bucket is permanently enclosed and protected against obstructions to its operation and against mishandling.

A further object is to provide a mechanism for emptying the drip bucket after a safety shut down, which is automatic, avoiding handling and which prevents accidental resetting of the control into a position to permit operation of the burner unless the drip bucket mechanism is in condition to provide subsequent safety shut down when necessary. This safety shut down mechanism includes a trip-free" reset device.

A further object is to provide a'control embodying a timing mechanism, a pump and a drip bucket mechanism interrelated but contained in a single unit, the interrelation of which permits separation of the individual elements thereof.

In the drawings:

Fig. 1 (Sheet 1) is a side elevation of the iechanism partly in section;

Fig. 2 (Sheet 2) is a view taken on the l ne 22 of Fig. l, and is a plan view of a mechanism with the cover shownin section;

Fig. 3 is an elevation view from/the right end z of Fig. 1, partly in section, taken on the line 3-3 of Fig. l, and showing the relay, and the reset mechanism for the drip bucket;

Fig. 4 (Sheet 3) is a vertical section on the line. 4-4 showing the gear mechanism and showing an additional part of the drip bucket control;

Fig. 5 (Sheet 4) is a mid section on the line 5-5 of Fig. 2 showing the pump drive, the epicyclic gearing, and part of the second gear train but with the spacing of the gears spread for clarity;

Fig. 6 is a horizontal section through the second gear train;

Fig. '1 (Sheet 3) is a further view of the epicyclic train taken on the line 1-1 of Fig. 1;

Fig. 8 (Sheet 1) is a view of the drip bucket connections taken on the line 8--3 at the right side of Fig. 1 just below the middle thereof;

Fig. 9 (Sheet 3) is a view of the oil line connections taken on the line 9-9 at the left side of Fig. 1 just below the middle;

Fig. 10 is a section on line llil0 of Fig. 9: and

Fig. 11 (Sheet 2) is a wiring diagram of the mechanism.

In general, the mechanism comprises a control unit including a timing motor 2!, an epicyclic 22, a second gear train 23, a relay switch mechagism 24, a pump 25, and a drip bucket mechanism The mechanism includes a base plate and a cover 3! extending upwardly from the base plate with three partitions 32, 33, and 34 secured to the base and adapted to support some of the component elements of this mechanism.

The timer 2| comprises an electric motor of conventional type that drives a shaft 35 (Figs. 5-7) The timer 2| is mounted at one side of the partition 32, and the shaft 35 passes through this partition to the other side thereof.

A hub 36 is secured to the shaft 35 by a pin 31. The hub 36 has a disc or wheel 38 extend ing therefrom. This disc 38 supports a plurality of pins 39. Each of the pins 39 supports a pawl 40, which pawls engage a pinion 4i floating on the shaft 35. The pins 39 also support planetary gears 42, having a first set of teeth 43 and a second set of teeth 44.

The teeth 43 mesh with teeth 45 on an eccentric 46 rotatable on a bushing that supports the shaft 35. The eccentric 46 carries a'dial 41 having holes 48 around one half of its periphery. These holes comprise graduations for a purpose to be described.

A second eccentric 50 is rotatable 0n the eccena tric 46. It carries a spring finger SI that has a pin 52 engageable in any of the holes 40. The outer eccentric 50 carries a strap 53 for operating the pump mechanism as will appear.

Returning to the second set of teeth 44 on the planetaries 42, these teeth mesh with those on an internal ring gear 58, secured to a case 51 attached to a hub 58, rotatably mounted on the shaft 35. The hub 50 receives a coupler by which it may be coupled with, or decoupled from, a complementary coupling element 8| on a second shaft 62 that projects through the partition 33 and is journaled therein. The other end of this shaft 62 is journaled in the partition 34.

The shaft 62 operates part of the second gear train 23. A pinion 55 is secured to the shaft 62 and engages the larger teeth of a double gear 86. The gear 68 is mounted on a shaft 61 supported in the partition 33 and supported in and extending through the partition 34. The smaller teeth of the gear 63 mesh with the larger teeth on a gear 68 rotatably mounted on the shaft 02. The smaller teeth on this gear 58 mesh with a gear 69 secured to the shaft 81. From the foregoing, it will be seen that the shaft 61 rotates at a much lower speed than does the shaft 02. The size of the several gears of this second gear train 23 may be selected to give the desired speed reduction.

Rigidly mounted on the end. of the shaft 61 is a stop plate 10. This plate (Figs. 1, 3, and 6) cooperates with a timing disc 1|. rotatably mounted on the shaft 61, and. from which a pin 12 extends. The pin 12 is normally maintained in engagement with an edge 13 on the stop plate by a coil spring 14. The timing disc II also has a series of screw receiving holes 15 around it, to receive a screw 16 which is disposed in any one of them for proper adjustment as will appear. The disc II may be rotated until it brings the pin or screw 16 against another edge 11 of the stop plate 10.

The timing disc H has notches 18 for engagement by a blade 80 of the relay mechanism 24. This bladeis secured to a bracket 8| pivotally mounted on another bracket 82 that supports a relay coil 83 on the partition 34. The bracket 8| carries also a switch blade 84, having a contact 85 that may close with a contact 36 on a bracket 81 secured to the partition 34. A coil spring 88 acts between a projection on the bracket 8| and ,a projection on the bracket 82, to urge the arm 00 away from the timing disc H and the switch arm 04 to break the contacts 05 and 8B. When the coil 83 is energized it operates the bracket 0| in the opposite direction, to bring the arm 80 into the upper one of the notches of the contact disc H, and to close the contacts 85 and 30.

The pump comprises an outer shell 92 securedto the bottom of the plate (Fig. 1).

A guide pin 93 in the bottom of the shell 92 supports a projection on a bellows end 94. This portion 94 is sealed to one end of a pum bellows 95, the other end of; which is sealed to a plate 90. The fitting 94 also receives one end of the pump connecting rod 91, the other end of which is secured to the strap 53 surrounding the eccentric 50.

A pump inlet I00 enters from the left of Fig. 1 and, as shown in Fig. 9, is secured to a fitting IOI disposed on the base 30. This fitting has a port I02 registering with a cross port I03 provided with a valve seat I04. The cross port I03 above the valve seat communicates with a cross port I05 having a valve seat I06 therein, and beyond this latter valve seat connects with a pipe I01.

The valve seat I04 receives a check valve I08 urged into the closed position by a spring I09.

This check valve I08 prevents back flow of oil into the inlet I00.

A second check valve H0 cooperates with the valve seat I06 against which it is normally urged by a spring I I I. This check valve IIO prevents back flow of oil from the line I01.

Within the fitting NH and also communicating with the port I03 above the valve I08 is another port II2. This port H2 is in communication with the interior of a cup II3 from which a pipe II4 (Fig. 1) extends into the interior of the pump casing 92. The cup H3 is secured in position by a screw H5.

From the description thus far, it may be seen that alternate suction and pressure within the pump chamber 92, provided by contraction and expansion of the bellows 95, will draw oil on through the inlet I00 past the valve I08, and then expel that oil past the valve I I0 into the line I01.

The line I01 is connected through a fitting I20 to join with a line I2I that leads to the pot B of the oil burner. Another pipe I22, comprising an over-flow pipe from the oil burner B, leads into the fitting I20 and connects with a pipe I23 leading into a drip bucket I25, Within a casing I26. The casing I 26 has drainage holes in the bottom.

The float or drip bucket I25 has within it and extending from it a rod I21. This rod extends through the bottom of the bucket I25 and has on its end a valve I28, urged by a'spring I29 into closed position. The spring I29 urges the rod I21 upwardly but may be compressed to drain off any oil or the like that asses into the bucket.

The upper end of the rod I21 passes through the bottom plate 30 and is pivotally secured to .a bracket I32 (Fig. 4) that, in turn, is pivoted at I33 between the partitions 33 and 34. A torsion spring I34 acts to hold-the bracket I32 and the bucket I25 up, with a light force. The bracket I32 has a projecting dog I35. The dog I35 is adapted, when elevated'by the spring I34. to rest under and support a ledge I36 projecting from a U-shaped bracket I31 pivoted at I38 between the partitions 33 and 34. A light torsion spring may be used to urge the bracket I31 clockwise about its pivot I38, as is shown in Fig. 4. It may be observed that upon lowering of the rod I21 the bracket I32 will pivot clockwise (Fig. 4) to withdraw the dog I35 from itssupport of the ledge I36, whereupon the bracket I31 will fall clockwise.

The bracket I31 carries a bi-metaliic switch blade I39, having a contact I40 at the end thereof, and supported on the bracket between two insulating blocks I31 and I 31 of porcelain or the like. This contact is adapted to be closed with the contact I4I on a second bi-metallic blade I42 that is secured to a bracket I43, between two insulating blocks I43 and I 43 of porcelain or the like. The bracket I43 is pivoted at I 44 to the partition 33, and urged in a counterclockwise direction about its pivot by a light torsion spring, as shown. An arm I45 on the bracket I43 carries an adjustable screw I46 engageable with a lug I41 supported between the partitions 33 and 34 adjustably to limit counterclockwise (Fig. 4) movement of the bracket I43.

This adjustment determines the initial relative positions of the contacts I40 and I.

The bracket I43 likewise carries a heater shield I48 supporting an electrical heating coil I49 that is in a circuit to be described, and which is adapted to influence the bi-metallic blade I42. The blade I39 is subject to ambient temperature, and compensates for effects of changes in ambient temperature on the blade I42. It may be seen that the initial relative positions of the contacts I40 and HI determine the length of time required for their closing and opening after energizing or deenergizing of the heater coil. I

The partition 34 has an opening I50 therein (Fig. 3). n the right side of the partition 34 in Fig. 1, as appears also in Fig. 3, is a trip-free reset lever II pivoted at I52. It has a handle portion I53 projecting through a slot in the bottom plate 30.

The inner end of the lever I5I has on it two insulative members I54 and I55 that project back through the opening I50 to be disposed respectively for contact with the switch 'blades I39 and I42. The member I54 rests upon, and is adapted for depression of, the bracket I32. It will be seen that when the handle I53 is pressed back, it will lift the members I54 and I55. These latter are so spaced that the member I55 may engage the blade I42 and pivot it with its bracket I43, and the member I54 may engage the blade I39 and pivot it with its bracket I31, so that the bracket I31 can be displaced to enable the ledge I36 to pass over the dog I35. But when the two blades I39 and H2 are engaged by their respective members I54 and I55, the contacts I40 and HI will be maintained out of engagement. When the handle I53 is drawn out, it will force the member I54 down against the bracket I32, causing depression of the rod I21, to open the valve I28 to drain any oil in the bucket I25.

The wiring diagram in Fig. 11 shows power lines at I60 and I 6|. A line I62 connects through a limit switch L1 into the primary of a transformer I63 and leads therefrom to the other power line I6I. A second line I64 connects into the line I62, inside the limit switch L1, and leads to the blade I42 and the contact I, which may close with the contact I40. That contact, in turn, is connected by a line I65 to the switch blade 84, which controls the contact 85. The contact 86 is connected by a line I66 through a limit switch L2 to the pump motor which, in turn, is connected by a line I61 to the other power line I6I. An additional line I66 is connected to the line I65 between the contact I40 and the switch blade 84 and leads to the fan motor which, in turn, is connected by a line I69 to the line I68.

The secondary circuit includes a room thermostat I10, one side of which is connected by a line "I to the secondary. This thermostat may have an anticipating heater A. Thence, from the secondary, the line I 12 leads into the heater I49. The other side of the heater I49 is connected by a line I13 into the coil 83 of the relay 24, the other side of which is connected by a line I14 back to the thermostat I10.

Operation It will be seen that transformer I63 is always across the lines. When the room thermostat I closes, demanding heat, it energizes the coil 83 to draw the bracket 8| down, closing the contacts 85 and 86 and setting the arm 80 against the adjacent one of the teeth 18 of the timing disc 1 I.

The heater I49, being in circuit, heats lip-to close the contacts I H and I 40 by warplng the blade I42. Thereupon, since the contacts "and 86 have been closed previously by the relay coil 83, the pump motor starts operating, and the fan motor is put in circuit to operate. Any excess warping of the blade I42, after closure of the contacts, merely pivots the bracket I43 clockwise about its pivot I44, without materially affecting the blade I39 and associated structure.

When the pump motor starts, the shaft is rotated. This causes rotation of the wheel 38 carrying the pins 39. These pins carry the ratchet dogs 40 which engage with the teeth on the gear M and rotate that gear at the same speed as the rotation of the wheel 38. The gear 4| meshes with the planetary gears 42 and they, in turn, mesh with the internal ring gear 56. This latter gear is not held against rotation at the start so that it is rotated as a unit through the foregoing connections with the wheel 38. Since the planetary gears 42 are engaged with the teeth 45 of the eccentric 46, they will cause the eccentric 45 to rotate as a unit with the shaft 35. As the eccentric 45 rotates, it rotates the eccentric with it, and this action lifts and depresses the pump rod 91. This pump rod then oscillates at the frequency of rotation of the shaft 35 and causes oil to be drawn into the inlet I00 and expelled through line I01 and the line I2I to the burner at a predetermined rate.

The rotation of the hub 58, attached to the casing 51, supporting the ring gear 56, causes rotation of the shaft 62 and, through the gear reduction 23, ultimately produces rotation at a slower speed of the shaft 61. The rotation of this shaft rotates the stop plate 10 to withdraw the shoulder 13 thereon from the pin 12 on the now held timing disc 1|, which is restrained against rotation by the arm 80. Here, the restraining force applied need only be sufficient to operate the epicyclic 22. In so doing it tightens the spring 14 which applies a restoring force to return the members 10 and H to their original relative positions, wherein the pin 12 and the shoulder 13 are in contact.

After a predetermined time of rotation of the pump shaft 35 and the driving shaft 61, the shoulder 11 will engage the pin 16 on the timing disc 1| to stop rotation of the shaft 61. The interval of time is adjustable by changing the pin 16 to another, hole 15, it being noted that the shaft 61 is rotated at a rate which will move the stop plate 10 a distance equal to one hole on the t ming disc in a time'interval approximating one minute. This stopping of the stop plate, in turn, stops rotation of the gear train 23 and ultimately of the ring gear 56. Thereupon, rotation of the wheel 36 causes the planetary gears 42 to rotate within the stationary ring gear 56 and-to impart a rotation to the eccentric 45 at a higher rate than before when the casing 51 was free. As a result, the pump operates at a higher speed to del ver greater quantities of oil.

If the room thermostat becomes satisfied during thelow feed rate of the pump, it will break the circuit of the coil 83 and of the heater I49. As soon as the coil 83 is deenergized, the spring 88 lifts its armature to break the contacts 35 and 86 and to lift the arm from its notch in the timing disc 1I.

' The first of the foregoing, namely, the opening of the contacts 85 and 86, stops the pump motor. The second, namely, lifting of the arm 80, permits the timin disc to be rotated by the spring 14 until it brings its pin 12 against the shoulder 13 on the stop plate at whatever point the pin 12 may have stopped when the motor stopp d.

The heater I48 coolsrelatively slowly after its circuit is broken. Its time for cooling is arranged to keep the fan motor in operation long enough so that proper scavenging of the burner.

may occur. When it does cool, it permits the blade I42 to separate the contact I from the contact I48 and open the circuit to the fan and provide an additional break in the circuit to the pump motor. Its period of heating provides sufficient delay in opening and closing of the contacts MI and I40 to prevent an immediate change in the position of the contact I and the circuits responsive to this contact, should the thermostat open and then reclose quickly.

If the heat delivered during the low stage of pump operation is insuflicient to satisfy the room thermostat, then the high stage of operation will begin. Should the room thermostat open during the high stage, the relay coil 83 will be deenergized, the contacts 85 and 86 separated, to stop the motor, the arm 80 will be withdrawn to permit return of the timing disc to its starting position relative to the stop plate, and the heater I49 will slowly cool, holding the contacts I40 and I closed for a scavenging period of operation of the fan and finally permitting them to open.

If ignition or combustion fails at any time when the pump is running, oil will build up in the pot to the over-flow level, and will then flow back through the over-flow pipes I22 and I23 into the drip bucket I25. When it builds up to a certain level within the drip bucket I25, it will overcome the eifect of the balancing spring I34 and cause the drip bucket to descend, removing the dog I35 from the ledge I 35, whereupon the bracket I31 pivots clockwise (Fig. 4) to withdraw the contact I48 from the contact I. This immediately breaks the circuits to the fan motor and to the pump motor, regardless of the condition of the room thermostat. The control will then return to its starting condition. As the flame is extinguished, no scavenging is required, although, generally speaking, an interval usually elapses before the manual reset is operated, and the heater I43 becomes cool.

When the foregoing drip bucket action occurs, manual reset is required to reestablish operation of the burner. This isaccomplished by drawing the handle I53 forward to force the member I54 down against the top of the bracket I32, depressing the rod I21, and opening the valve I28. This position is held until oil stops draining from the bottom of the casing I25, indicating that the BXCGSS has drained from the bucket I25. Thereupon the handle I53 is pressed'backwardly, to permit the spring I28 to reclose the valve I28 and to cause the member I54, engaging the blade I39, to lift it toward reset position. Prior to any engagement of the contacts I40 and I, the member I55 will engage the blade I42 and lift it, to keep the contacts apart. The spring I34 lifts the bracket I32 to relocking position (if, and only if, the bucket I25 is empty). Thereupon, release of thehandle I53 will permit the bracket I31 to fall, to place its ledge I36 against the dog I35, and to withdraw from both blades, leaving them in operating condition determined by the condition of the heater I43. If the bucket has not been emptied during this last operation, the latching elements I35 and I35 will not engage, and the contacts will never be disposed in opening interval of the anticipating heater, based upon constant room temperature, may be less than the length of the low speed operation. This imperative opening interval will be stretched when heat loss is increased, and will permit higher speed operation to overcome such loss.

Two limit switches L1 and L2 have been shown in Fig. 11. These switches may take the form of maximum temperature controls conveniently located in the furnace bonnet or stack to open when a maximum furnace temperature is reached. One may be an overall high temperature limit switch. In many cases, one or the other may be eliminated. In case the limit switch L1 opens, the entire circuit is deenergized. When that limit switch recloses, if the thermostat I18 is closed, the mechanism will start over again on low speed operation, because release of the arm upon deenergization of the coil 83 permits the timing disc and locking disc to assume their relative starting positions. This limit switch may be desirable under conditions where operation of the burner at such intense heats is accompanied by such a lag that usually the thermostat will be satisfied by delivery of'such heat to the room during the interval the limit switch is open.

The limit switch L2 is disposed in the pump motor circuit. When it opens, the pump motor stops. However, the rest of the circuit remains energized as long as the room thermostat remains unsatisfied. The fan will continue operating and the control will remain in whatever position it had attained. Usually, the slow speed operation will be insufficient to cause the limit switch to open. In any case, upon reclosure of the limit switch L2, the pump motor will restart,

and the cycle will proceed as if the hiatus had.

not occurred. Of course, if the room thermostat opens while the limit switch is open, the control will return to starting position, and, upon reclosure of the limit switch, may start a new cycle.

As previously noted, the second eccentric 58, bearing upon the first eccentric 45 (Fig. 5), is adjustable to have a particular position relative to the. first eccentric. It will be seen that when the point of maximum thickness of the eccentric 58 is aligned with the point'of maximum thickness of the eccentric 45, the pump rod 91 will be lifted the greatest distance above the center of the shaft 35 and will descend a maximum distance below that line. When the eccentric 58, however, is turned at relative to the eccentric 45, it will present its widest point adjacent the narrowest point of the eccentric 45 and will reduce the lift and fall of the pump rod to a minimum.

To this end, the spring clip 5I may be drawn back to withdraw the pin 52 from the opening 48 in the disc 41, then rotated to shift the eccentric 50 relative to the eccentric 45, and released to reengage the pin 52 in another of the holes 48. Fig. 7 shows that the holes 48 extend over 180 of the disc 41. By this means, the holes 48 comprise graduations, as well as setting holes, and

the pump stroke may be adjusted between minimum and maximum positions.

The interval of the low feed period is determined by the speed of the motor, the reduction effected through the gearing 23 and the angular distance between the pin Hi and the shoulder 11 on the stop plate 10. To change the length of this interval, it is necessary only to change the position of the pin 16 to another hole 15.

It will be seen further that providing teeth around the entire periphery of the timing disc H enables that disc to be stopped by the arm 80 substantially immediately after rotation of the shaft begins. The stop plate is fixed to the shaft and its angular position in space is fortuitous,.

but the only critical factor is the relative positions of the plates 10 and I I.

It will be seen from the foregoing that the invention provides a control that determines the quantitative operation of a burner in response to time and trend. The time factor enters throughthe fixed interval between the starting low speed operation, and the high speed operation; and the trend factor enters in through the element of how readily the room thermostat may be satisfied The control also embodies numerous safety features, such as those described in detail and those apparent from the disclosure.

It is fairly evident how the cycle could be applied to other than heat supply, and particularly its application to a refrigeration cycle. Thus the ultimate drive could be to a compressor pump, to produce a relatively slow operation for an initial predetermined period, and a consequent low refrigeration production for that period. If the refrigeration system involves circulation of a Cooling medium, such as brine or air, the control would provide the two-speed operation of the brine pump or air circulator.

What is claimed is:

1. In a control for a liquid fuel burner, power means including a driving member, fuel delivery means operated by said driving member, the quantity rate of fuel delivery of said means being determined by the speed of the driving member, control means to determine the speed of operation of said driving member, said control means having timing mechanism operable to drive said driving member at a first speed for a predetermined time interval, and thereafter to drive the same at a second speed.

2. In a control for a heat-change producing device, power means, means for delivering a heatchange medium adapted to be operated by said power means, planetary gear means interposed between the power means and the delivery means, said planetary gear means including a member movable to produce one speed transmission rate from the power means to the delivery means and fixable to produce another such rate, automatic means operable to hold fixed said movable and fixable means to change the rate of transmission and thereby to change the rate of delivery of said heat-change medium, said last-named means comprising a stop mechanism to stop rotation of the movable and fixable means after a predetermined amount of rotation thereof.

3. In a control for a heat-change producing device, power means, means for delivering a heatchange medium adapted to be operated by said power means, planetary gear means interposed between the power means and the delivery means, said planetary gear means including a member movable to produce one speed transmission rate from the power means to the delivery means and fixable to produce another such rate, automatic means operable to hold fixed said movable and fixable means to change the rate of transmission and thereby to change the rate of delivery of said heat-change medium, said last-named means comprising a stop mechanism to stop rotation of the movable and fixable means after a predetermined amount of rotation thereof, said stop mechanism comprising two relatively movable members, means connecting one member with the movable and fixable member, interengaging means between the two stop mechanism members adapted to be engaged after relative movement of said members, and means to adjust the interengaging means to adjust the amount of relative movement before the members are stopped.

4. In a control for use with a heat-change producing device, power means, means for delivering a heat-change medium adapted to be operated by said power means, planetary gear means interposed between the power means and the delivery means, said planetary gear means including a member movable to produce one speed transmission rate from the power means to the delivery means and fixable to produce another such rate, automatic means operable to hold fixed said movable and fixable means to change the rate of transmission and thereby to change the rate of delivery of said heat-change medium, said lastnamed means comprising a stop mechanism to stop rotation of the movable and fixable means after a predetermined'amount of rotation thereof, said stop mechanism comprising two relatively movable members, means connecting one member with the movable and fixable member, said other member being normally movable relative to the one member, means urging the two members toward a predetermined relative starting position, means to hold said other member, said last-named means being operated upon operation of the power means, interengaging means between the two stop mechanism members adapted to be engaged after relative movement of said members.

5. In a control for a heat-change producing device, power means, means for delivering a heatchange medium adapted to be operated by said power means, planetary gear means interposed between the power means and the delivery means, said planetary gear means including a member movable to produce one speed transmission rate from the power means to the delivery means and fixable to produce another such rate, automatic means operable to hold fixed said movable and fixable means to change the rate of transmission and thereby to change the rate of delivery of said heat-change medium, said last-named means comprising a stop mechanism to stop rotation of the movable and fixable means after a predetermined amount of rotation thereof said stop means comprising two members relatively movable and movable together, means to limit the relative movement of the two members to a predetermined amount, means to cause one of the members to move with movement of the movable and fixable member, and means to stop movement of the other member, whereupon the first member may move only the distance provided by the relative movement between them and then stop to stop the movable and fixable member.

6. In a control for a heat-change producing device, a power means, a delivery means operable to deliver a heat-change medium at two different rates to the said device and transmission means 11 to produce the two different rates of medium deliveries, said transmission means including a member movable to provide a first rate of delivery during movement and a second rate of delivery when stopped, a stop means for said movable means, means to pre-set the movable means relative to the stop means to obtain a predetermined movement of the former before operation with the latter to effect stopping, and means to move the movable means by the power means until it is stopped and thereafter to change the rate of delivery of the medium delivery means.

7. In a fuel feeding mechanism capable of delivering different quantities of fuel, means to start said mechanism in operation to deliver fuel in a first quantity, timing means, means to start the timing means upon start of the fuel feeding mechanism, and means operated by the timin means to change the rate of operation of the fuel feeding mechanism at the end of a, predetermined time interval after start of the timing means.

8. Int. fuel feeding mechanism capable of delivering different quantities of fuel, means to start said mechanism in operation to deliver fuel in a first quantity, timing means, means to start the timing means upon start of the fuel feeding mechanism, means operated by the timing means to change the rate of operation of the fuel feeding mechanism at the end of a predetermined time interval after start of the timing means, and means to adjust the rate of delivery of the fuel feeding mechanism.

9. In a control for a fuel feeding device of the variable speed pump type, the combination of means energizable to cause the pump to operate at one speeds timing means, means to start operation of the timing means upon start of the first mentioned energizable means, and means operated by the timing means after a predetermined period of operation thereof, to cause the pump to operate at a different speed.

10. In a control for fuel burners, a fuel supply device, a motor, a circuit for the motor, a shaft driven by the motor and connectable to the fuel supply device for efiecting delivery of fuel thereto, timing means operated by the motor and means interconnected with the timing means operable to increase the speed of the driven shaft after it has operated a predetermined time interval to increase the rate of fuel delivery.

11. In a burner control for use with a fuel delivery means operable to produce different rates of fuel delivery, timing means, said timing means being adapted to produce operation of the fuel delivery means at one rate for a predetermined 12 period and thereafter to produce operation at a different rate. an electrical control means energizable to cause said timing means to produce said period of operation, and means to cause the timing means to return to starting condition upon release of said control means.

12. In a control, a pump for a burner or the like, a driving shaft,,gear mechanism for connecting the driving shaft with the pump, means in the gear mechanism to establish a first speed of the pump, means in the gear mechanism to establish a second speed of the pump, timing means act ated by the first means as a function of the dur tion of the operation thereof to actuate the ond named means, to operate the pump at second speed after a predetermined period of operation at the first speed.

13. In a control, a pump for a burner or the like, a driving shaft, planetary gear'mechanlsm for connecting the driving shaft with the pump, means in the gear mechanism to establish a first speed of the pump, including a movable member, that acts, when obstructed, to establish a second speed of the pump, means in the path of the movable member to stop the same after predetermined movement thereof, to cause the pump to be changed from first speed to second speed.

GEORGE D. BOWER.

REFERENCES crrnn The following references are of record in the file of this patent:

UNITED STATES PA'IE'NTS Number Name Date 944,255 Bong Dec. 28, 1909 998,647 Smith July 25, 1911 1,572,365 Rotter Feb. 9, 1926 1,674,051 McCabe June 19, 1928 1,723,031 Good Aug. 6, 1929 1,745,062 Scheminger Jan. 28, 1930 1,787,743 Good Jan. 6, 1931 1,983,229 Hillier Dec. 4, 1934 2,022,879 Calberg Dec. 3, 1935 2,038,675 Ray Apr. 28, 1936 2,178,672 Perkins Nov. 7, 1939 2,214,912 Valjean Sept. 17, 1940 2,263,822 Wilson Nov. 25, 1941 2,276,794 Ricci Mar. 17, 1942 2,337,476 Landon Dec. 21, 1943 2,339,618 Crago Jan. 18, 1944 2,348,143 Miller May 2, 1944 2,348,958 Cello May 16, 1944 2,397,987 Senninger Apr. 9, 1946

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