US3685945A

US3685945A - Pneumatic fuel control system and method of operating the same

Info

Publication number: US3685945A
Application number: US64064A
Authority: US
Inventors: Arthur L Good
Original assignee: Robertshaw Controls Co
Current assignee: Robertshaw Controls Co
Priority date: 1970-07-24
Filing date: 1970-07-24
Publication date: 1972-08-22
Anticipated expiration: 1989-08-22

Abstract

This disclosure relates to a fuel control system wherein a source of fuel is adapted to be interconnected to a burner means when a pneumatically operated actuator means is interconnected to a pneumatic source, the system including electrical ignition means and time delay means so constructed and arranged that the electrical ignition means is first actuated to ignition temperature before the control system will cause the pneumatic source to be created and simultaneously therewith will initiate operation of a time delay means so that if the main burner means is not ignited within a predetermined time period after the fuel first issues therefrom, the time delay means will terminate the operation of the control system.

Description

United States Patent Good [54] PNEUMATIC FUEL CONTROL SYSTEM AND METHOD OF OPERATING THE SAME [72] Inventor: Arthur L. Good, c/o Robertshaw Controls C0., Midwest Development Center, PO. Box 435, Elkhart, Ind. 46514 [22] Filed: July 24, 1970 211 Appl.No.: 64,064

[52] US. Cl ..431/6, 431/66 [51] lnt.Cl ..F23n 5/00 [58] Field of Search ..431/6, 66; 236/15 [56] References Cited UNITED STATES PATENTS 3,384,071 5/1968 Body eta] ..l26/273X 3,457,020 7/1969 Hine ..431/66 51 Aug. 22, 1972 Primary Examiner-Edward G. Favors Attorney-Gander, Candor & Tassone [57] ABSTRACT This disclosure relates to a fuel control system wherein a source of fuel is adapted to be interconnected to a burner means when a pneumatically operated actuator means is interconnected to a pneumatic source, the system including electrical ignition means and time delay means so constructed and arranged that the electrical ignition means is first actuated to ignition temperature before the control system will cause the pneumatic source to be created and simultaneously therewith will initiate operation of a time delay means so that if the main burner means is not ignited within a predetermined time period after the fuel first issues therefrom, the time delay means will terminate the operation of the control system.

20 Claims, 7 Drawing Figures PKTENTI-ibwsaz 1912 3.685945 SHEET 1 OF 7 INVENTOR ARTHUR LGOOD BY M'idM-dn HIS ATTORNEYS PATENTEBmze m2 3,685,945 sum s or 1 I86 95D n40, ,IIID f I I L-- INVENTOR ARTHUR L. GOOD W /MA HIS ATTORNEYS P'A'TE'NTEDmsze I972 3.685. 945

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INVENTOR ARTHUR L. GOOD W'vM HIS ATTORNEYS PNEUMATIC FUEL CONTROL SYSTEM AND METHOD OF OPERATING THE SAME This invention relates to an improved fuel control system as well as to an improved method for operating such a control system or the like.

It is well known that a fuel burning apparatus can have the main burner means thereof interconnected to a fuel source when a pneumatically operated valve means is interconnected to a pneumatic source.

However, one of the features of this invention is to provide such a control system wherein the pneumatic source creating device for the control system is not energized until after an electrical ignition means for the main burner means has reached ignition temperature, the ignition means when reaching ignition temperature also causing the start of the operation of a time delay means which, if the main burner means is not ignited within a predetermined time period after the creation of the pneumatic source, will terminate the operation of the control system.

Another feature of this invention is to provide a pneumatically operated time delay means which has an opening means that leads to the atmosphere, the opening means being opened and closed by a valve means being responsive to the ignition temperature of the electrical ignition means for the main burner means.

One embodiment of this invention for performing the above described features includes a pneumatic source creating device and an electrical ignition means interconnected together in an electrical circuit in such a manner that when the ignition means is first energized, the same must first reach ignition condition, which ignition condition is sensed by a temperature responsive electrical switch that moves to one posiu'on thereof to interconnect the pneumatic source creating device across the power source so that the operating pneumatic source creating device can operate pneumatically operated actuator means disposed between the fuel source conduit and the main burner means. Simultaneously with the movement of the electrical switch means of the pneumatic source creating device, the electrical switch opens an opening means in a time delay pneumatic actuator which cannot be operated by the pneumatic source creating device unless the valve means is again moved to its closed position by the temperature sensing electrical switch means sensing that the main burner means has not been ignited within a predetermined time period after the ignition means had first reached its ignition temperature.

Accordingly, it is an object of this invention to provide an improved fuel control system having one or more of the novel features set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved method of operating such a control system or the like.

Other objects, uses, and advantages of this invention are apparent upon a reading of this description, which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIGS. 1 is a schematic view, partially in cross section, illustrating one control system of this invention;

FIG. 2 is a view similar to FIG. 1 and illustrates another embodiment of the control system of this invention;

FIG. 3 is a view similar to FIG. 1 and illustrates another embodiment of the control system of this invention;

FIG. 4 is a view similar to FIG. 1 and illustrates another embodiment of the control system of this invention;

FIG. 5 is a view similar to FIG. 1 and illustrates another embodiment of the fuel control system of this invention;

FIG. 6 is a view similar to FIG. 1 and illustrates another embodiment of the fuel control system of this invention;

FIG. 7 is a view similar to FIG. 1 and illustrates another embodiment of the fuel control system of this invention.

While the various features of this invention are hereinafter described and illustrated as being particularly adapted to provide a fuel control system and a method of operation for a laundry drying machine or the like, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide control means and methods for other types of apparatus as desired.

Therefore, this invention is not to be limited to only the embodiments illustrated in the drawings because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIG. 1, one embodiment of this invention is generally indicated by the reference numeral 10 and comprises a fuel source conduit means 11 adapted to be interconnected to a main burner means 12 of a domestic laundry drying machine (not shown) or the like by a conduit means 13 having four

valve seats

14, 15, 16, and 17 disposed in series between the fuel source conduit 1 1 and the main burner means 12.

The valve seat 15 in the conduit 13 is controlled by a pressure regulator means 18 that includes a flexible diaphragm 19 carrying a valve member 20 that is urged to its open position by a compression spring 21 in a conventional manner whereby the pressure regulator 18 tends to maintain a predetermined constant pressure of the fuel flowing from the fuel source conduit 11 to the burner means 12 when the

valve seats

14, 16 and 17 are opened in the manner hereinafter described.

The

valve seats

14, 16 and 17 are adapted to be controlled by pneumatically operated

actuators

22, 23 and 24 each comprising a cup-shaped housing member 25 having its open end 26 closed by a flexible diaphragm 27 that cooperates therewith to define a chamber 28 therebetween. The flexible diaphragms 27 of the

actuators

22, 23 and 24 respectively carry

valve members

29, 30 and 31 adapted to move in unison with their respective diaphragms 27 and respectively control the opening and closing of the

valve seats

14, 16 and 17, the valve member 31 and valve seat 17 being so constructed and arranged so as to provide for fuel modulation in a manner hereinafter described. A compression spring 32 is disposed in each chamber 28 of the

actuators

22, 23 and 24 to normally tend to maintain the

valve members

29, 30 and 31 in their closed positions against their

respective valve seats

14, 16 and 17.

A pneumatic source creating device 33 is provided in the system 10 and comprises an electrically operated vacuum pump having its inlet side 34 fluidly interconnected to a conduit means 35 that, in turn, is fluidly interconnected by

branch conduits

36, 37 and 38 to the chambers 28 of the

respective actuators

22, 23 and 24. The branch conduit 38 has a restriction 39 therein intermediate the conduit 35 and the chamber 28 of the actuator 24 for a purpose hereinafter described, the conduit 38 also being disposed in fluid communication with a conduit means 40 intermediate the restrictor 39 and the actuator 24. The conduit 40 has an open end 41 controlled by a bimetallic temperature sensing disc construction 42 which senses the temperature effect of the burner means 12 and as the temperature effect of the burner means 12 increases beyond a predetermined temperature effect, the bimetal member 42 has its central portion warped upwardly in FIG. 1 to progressively open the opening means 41 in the conduit 40 for a purpose hereinafter described.

The conduit 35 has a restriction 43 therein that leads to the atmosphere at an opened end 44 having porous filtering material 45 disposed therein for a purpose hereinafter described, the restriction 43 being so constructed and arranged that the branch conduit means 36, 37 and 38 are disposed intermediate the restrictor 43 and the vacuum pump 33.

A pneumatically operated time-delay means 46 is provided for the fuel control system and comprises a cup-shaped housing member 47 having its open end 48 closed by a flexible diaphragm 49 to define a chamber 50 therebetween, the flexible diaphragm 49 carrying an actuating post means 51 to move in unison therewith and operate a switch blade 52 of an electrical switch 53 in a manner hereinafter described. A compression spring 54 is disposed in the chamber 50 of the pneumatically operated time-delay means 46 to tend to maintain the flexible diaphragm 49 in the up position illustrated in FIG. 1 wherein the switch blade 52 of the switch 53 is held in electrical contact with a fixed contact 55 of the switch 53 for a purpose hereinafter described.

The vacuum source conduit 35 is interconnected to a branch conduit 56 that leads to the chamber 50 of the pneumatically operated time-delay means 46, the conduit 56 having a restriction 57 therein for a purpose hereinafter described. Another conduit means 58 is also disposed in fluid communication with the chamber 50 of the pneumatically operated time-delay means 46 and has an open end 59 adapted to be opened and closed by a valve member 60 carried on a switch blade means 61 of a temperature-responsive electrical switch construction 62 operated and described in detail hereinafter.

An electrical circuit means, generally indicated by the reference numeral 63 in FIG. 1, is provided for the control system 10 and comprises a pair of power source leads L and L respectively interconnected to

electrical leads

64 and 65, the lead 65 being directly interconnected to one side 66 of the electrical operating means 67 of the vacuum pump 33 while the other side 68 of the electrical operating means 67 of the vacuum pump 33 is interconnected by a lead 69 to a switch blade means 70 of the electrical switch 62.

An electrical motor 70 is provided for the laundry machine for rotating the laundry-receiving drum (not shown) thereof as well as to operate the conventional fan or blower means thereof, the electrical motor 7' having a starting winding 71 and a running winding 72 as conventional in the art. One side 73 of the starting winding 71 is interconnected by a lead 74 to the power source lead 65. One side 75 of the running winding 72 is interconnected by a lead 76 to the lead 74. The other side 77 of the running winding 72 is interconnected to a lead 78 as well as to a centrifugally operated switch blade 79 that is normally disposed in electrical contact with the other end 80 of the starting winding 71 of the motor 70 in the manner illustrated in FIG. 1 but which will move away from the end 80 of the starting winding 71 and into contact with an electrical contact 81 when the motor 70 is operating so as to disconnect the starting winding 71 from being disposed across the power source leads L and L as will be apparent hereinafter.

An electrical timer means 82 is provided in the circuit means 63 and has one side 83 thereof interconnected to the previously described lead 78 while the other side 84 thereof is interconnected by a lead 85 to the lead 65. The timer means 82, when energized in a manner hereinafter described, will maintain a pair of

switch blades

86 and 87 respectively in contact with a pair of contacts 88 and 89 whereas when the timer means 82 reaches its end of cycle position, the timer means 82 returns the

switch blades

86 and 87 to their open position as illustrated in FIG. 1 until the control system 10 is again turned to its on position in a manner hereinafter described.

The contact 88 of the timer means 82 is interconnected by a lead 90 to the switch blade 61 of the electrical switch 62. The other contact 89 of the timer means 82 is interconnected by a lead 91 to the fixed contact 55 of the electrical switch 53.

The contact 81 of the centrifugal switch means of the motor 70' and the movable contact blade 52 of the switch 53 are respectively interconnected together, as well as to the lead 78, by

leads

92 and 93.

The lead 64 that is interconnected to the power source L is interconnected to a switch blade 94 of a door operated electrical switch 95 which, when the dryer door is in its open position, will maintain the switch blade 94 against a contact 96 that is interconnected by a lead 97 to one side 98 of a lamp means 99 that has its other side 100 interconnected by a lead 102 to the lead 65 whereby with the dryer door in its open position as illustrated in FIG. 1, the light 99 is placed across the power source lead L and L to light the interior of the dryer. However, when the dryer door is disposed in its closed position, the switch blade 94 is moved out of electrical contact with the contact 96 to terminate the operation of the light 99 and is placed and held in electrical contact with a contact 103 which permits the circuit means 63 to be energized in a manner hereinafter described. The contact 103 of the door operated switch means 95 is interconnected by a lead 104 to a switch blade 105 that is normally disposed in electrical contact with a contact 106 as long as the temperature effect of the burner means 12 does not exceed a high safe limit.

In particular, the switch blade 105 is interconnected by tying means 107 to a birnetal temperature-sensing member 108 that holds the switch blade 105 against the electrical contact 106 as long as the temperature effect of the burner means 12 is below a high safe limit. However, when the temperature effect of the burner means 12 exceeds the high temperature safe limit thereof, the

bimetal member 108 warps uwardly to move the switch blade 105 away from the contact 106 to terminate the flow of current through the circuit means 63 until the temperature effect falls below the high safe limit.

The contact 106 is interconnected by a lead 109 to a switch blade 110 of a manually operated electrical switch means 111 that normally maintains the switch blade 110 against a fixed contact 112 that is intercOnnected by a lead 113 to the switch blade 87 of the timer means 82. However, when the housewife or the like pushes inwardly on a start button means 114 of the switch means 111, the switch blade 110 is momentarily moved out of electrical contact with the contact 112 and placed in electrical contact with a fixed contact 115 that is interconnected by a lead 1 16 to the lead 78. However, when the housewife subsequently releases the push button 114 or when the switch means 111 automatically operates, the same automatically returns the switch blade 1 to the position illustrated in FIG. 1 for a purpose hereinafter described.

An electrical ignition coil 117 is disposed adjacent the outlet end 118 of the burner means 12 to ignite the fuel issuing therefrom in a mannere hereinafter described, one side 118' of the ignition means 117 being interconnected by a lead 119 to the lead 65. The other side 120 of the ignition means 117 is interconnected by a lead 121 to a switch blade means 122 of the electrical switch 62 which is normally disposed in electrical contact with the switch blade 61 when the switch blade 61 is holding the valve member 60 in a manner to close the opening 59 of the conduit 58.

A temperature-responsive bimetal member 123 is provided for the electrical switch 62 and is adapted to sense the temperature of the ignition means 117 as well as the presence or absence of flames at the main burner means 12. The movable end 124 of the bimetal member 123 is interconnected by suitable tying means 125 to the movable end 126 of the switch blade 61 so that the switch blade 61 will move in unison with the bimetal member 123 in a manner hereinafter described.

The switch blade 86 of the timer means 82 is interconnected by a lead 127 to the lead 7 8.

From the above, it can be seen that the control system 10 of this invention can be formed from a relatively few parts in an economical manner to function and operate in a unique manner now to be described.

When the housewife or the like desires to operate the control system 10 from the off condition illustrated in FIG. 1 wherein the high limit safety switch blade 105 is disposed against the contact 106 and the dryer door is in its closed position so that the switch blade 94 is against the contact 103, the housewife or the like momentarily pushes inwardly on the start button 114 to move the switch blade 110 into electrical contact with the fixed contact 115 whereby the power source lead L is effectively connected to the ends 77 and 80 of the running and starting winding 72 and 71 of the motor 70' so that the motor 70' is placed across the power source leads L and L and begins to operate. Also, the timer means 82 is now placed across the power source leads L and L to begin to operate and move the

switch blades

86 and 87 respectively against the contacts 88 and 89.

As the motor is now operating, the centrifugally operated switch blade 79 thereof moves away from the end 80 of the starting winding 71 and is held by centrifugal force against the stationary contact 81 and since the switch blade 110 is of the momentary switch means 111 has now moved back against the contact 112, it can be seen that the running winding 72 of the motor 70' now remains placed across the power source leads L and L because the power source L is now interconnected by switch blade 110 to lead 113, switch blade 87, contact 89, lead 91 and closed switch means 53 to lead 93, which is electrically interconnected to both leads 92 and 78 which are electrically interconnected to the side 77 of the running winding 72. Thus, as long as the control system 10 operates normally, the switch means 53 will remain in its closed position to continuously operate the main motor 70' of the system 10 until the timer means 82 reaches its end of cycle position to move the

switch blades

86 and 87 to their open positions as illustrated in FIG. 1 to terminate the operation of the motor 70' as well as the other parts of the control system 10 now to be described.

With the switch means 53 now, in effect, interconnecting the power source lead L to place the timer means 82 across the power source leads L and L it can be seen that the power source lead L that is interconnected to the lead 78 by the switch means 53 is also interconnected by lead 127, switch blade 86, contact 88 and lead 90 to the switch blade 61 of the switch means 62 which is disposed in electrical contact with the switch blade 122 whereby the ignition coil 117 is, in effect, placed across the power source leads L and L and begins to heat to ignition temperature.

The electrically operated means 67 of the pneumatic pump 33 is not being energized at this time because the side 68 thereof is interconnected to the switch blade 70 of the switch means 62 which, in turn, is not electrically connected at this time to the power source lead L as the blade 70 is spaced from the blade 61.

However, when the ignition coil 117 reaches ignition condition, the temperature thereof is sensed by the bimetal member 123 of the electrical switch means 62 and the free end 124 thereof warps to the right in FIG. 1 and, through the tying means 125, moves the free end 126 of the switch blade 61 therewith out of electrical contact with the switch blade means 122, to terminate the flow of current through the ignition coil 117, and into electrical contact with the switch blade 70 to effectively place the electrical operating means 67 of the vacuum pump 33 across the power source leads L and L so that the vacuum pump 33 can now begin to operate. The movement of the switch blade 61 against the switch blade 70 also causes the valve means 60 to move away from the end 59 of the conduit 58 so that the chamber 50 of the pneumatically operated timedelay means 46 is fully interconnected to the atrnosphere.

The vacuum pump 33 is now operating and the same evacuates the chambers 28 of the pneumatically operated

actuators

22, 23 and 24 to respectively move the

valve members

29, 30 and 31 to their open positions so that fuel can flow from the fuel source conduit 11 to the main burner means 12 and issue out of the open end 118 thereof to be ignited by the previously heated ignition coil 117.

The fuel now ignited and continuously burning at the main burner means 12 is sensed by the bimetal member 123 of the electrical switch means 62 so that the bimetal member 123 maintains the switchblade 61 against the switchblade 70 to continuously operate the vacuum pump 33, the continuously operating vacuum pump 33 having no effect on the time delay means 36 because the restrictor 57 in the conduit means 56 prevents the vacuum pump 33 from evacuating the chamber 50 an amount sufficient to move the flexible diaphragm 49 thereof downwardly because the atmosphere is fully connected to the chamber 50 by the opened end 59 of the conduit means 58.

However, if during the initial start-up of the control system just after the ignition coil 117 initially reached its ignition condition to cause the switchblade 61 to move to the right away from the switchblade 122 and into contact with the contact 70 so that fuel could issue from the main burner means 12 by the now operating pneumatic source creating device 33, a subsequent ignition of that issuing fuel does not take place within a predetermined time period, the bimetal member 123 will begin to cool as the ignition means 117 is no longer energized and the free end 124 of the bimetal member 123 will move back to the left in FIG. 1 carrying the switchblade 61 thereof so that the valve member 60 will close off the opening 59in the conduit 58. While the vacuum pump 33 is now turned off, the vacuum condition in the

lines

56, 35, 36, 37 and 40 will now effectively evacuate the chamber 50 of the pneumatically operated time delay means 46 so that the resulting pressure differential across the diaphragm 49 thereof will pull the diaphragm 49 downwardly in opposition to the force of the compression spring 54 whereby the actuating post means 51 will move the switchblade 52 out of electrical contact with the fixed contact 55 and, thereby, disconnect the electric motor 70, timer means 82, and ignition coil 117 from across the power source leads L and L to terminate the operation of the control system 10 until restarted by the housewife or the like. Air can subsequently return to the chamber 50 of the time delay means 46 through the controlled bleed restrictor means 43 in the conduit 35, the returning air into the conduit means 35 by the restrictor 43, causing the

valve members

29, 30 and 31 of the

actuators

22, 23 and 24 to be moved to their closed position to terminate the flow of fuel to the main burner means 12 as the chambers 28 of the

actuators

22, 23 and 24 return to atmospheric condition.

Thus, it can be seen that once the ignition coil 117 initially reaches its ignition temperature, a movement of the bimetal member 123 to the right in FIG. 1 initially takes place to open the end 59 of the conduit means 58, as well as to place the vacuum creating source means 33 across the power source leads L and L whereby a predetermined time period is started in which the main burner means 12 must be ignited by the ignition coil 117 and, if ignition does not take place within that time period, the bimetal member 123 moves back to the left, closing the opening 59 so that the time delay actuator 46 can be actuated to terminate the operation of the control system 10.

During normal operation of the control system 10, it can be seen that the temperature effect of the main burner means 12 will be substantially maintained by the temperature responsive device 42, because as the temperature of the burner means 12 exceeds a predetermined temperature effect thereof, the bimetal member 42 warps upwardly to progressively open the opening 41 in the conduit means 40 so as to permit air to return to the chamber 28 of the actuator 24 and move the valve member 31 closer to the valve seat 17 to decrease the amount of fuel flowing to the burner means 12.

In this manner, the actuator means 24 is modulated by the temperature responsive device 42 so as to tend to maintain the temperature effect of the burner means 12 at a predetermined temperature effect throughout the entire cycle of operation of the system 10.

When the control system 10 is operating in the normal manner previously described to continuously operate the burner means 12 and the timer means 82 nears its end-of-cycle position, the timer means 82, through conventional cam means well known in the art and not shown, will first interrupt the current supply to the vacuum pump 33 by opening the switchblade 86 away from the contact 88 whereby air will now bleed through filter means 45, and restrictor 43, into the chambers 28 of the

actuators

22, 23 and 24 to close the valve seats 14, 16 and 17 so that the operation of the burner means 12 will be terminated. After an established cool-down period with the motor rotating the laundry receiving drum, the timer means 82 will open the switchblade 87 away from the contact 89 to terminate the operation of the motor means 70 whereby the control system 10 will be in its fully off position, as illustrated in FIG. 1.

Thus, it can be seen that the control system 10 of this invention is so constructed and arranged that the ignition means 117 thereof must first reach ignition condition before the pneumatic source creating device 33 will be energized and once the ignition coil 117 reaches ignition condition, the pneumatically operated time delay means of this invention will terminate the operation of the control system if the burner means 12 is not ignited within a predetermined time period that has its starting point, being the time when the ignition coil 117 first reaches its ignition condition.

Another control system of this invention is generally indicated by the reference numeral 10A in FIG. 2 and parts thereof similar to the control system 10 previously described will be indicated by like reference numerals followed by the reference letter A.

As illustrated in FIG. 2, the pneumatic control means of the control system 10A are substantially identical to the pneumatic control means of the control system 10 of FIG. 1, except that an additional restrictor 128 has been placed in the conduit means 58A intermediate the chamber 50A of the pneumatically operated time delay means 46A and the electric switch means 62A for a purpose hereinafter described.

The electrical circuit means 63A for the control system 10A includes the previously described door operated switch means A and high limit safety switchblade means A. However, the starting electrical switch means 111A includes two switchblades, 129 and 130, that operate in unison and are respectively normally disposed out of engagement with a pair of fixed contact means 131 and 132, the switchblade 129 being interconnected to the lead 109A, while the switchblade is interconnected by a lead 133 to the stationary switchblade 70A of the switch means 62A. When the starting switch means 111A is moved inwardly by the housewife to start the control system A, the switchblades 129 and 130 remain in contact with contacts 131 and 132 throughout the entire cycle of operation, with the timer means 82A returning the switchblades 129 and 130 to the position illustrated in FIG. 2 at the end of cycle position of the system 10A.

The timer means 82A includes a pair of

switchblades

134 and 135 normally being respectively disposed against contact means 136 and 137 when the timer means 82A is in its ofi condition, the switchblade 134 being electrically interconnected by a lead 138 to the contact 131 of the starting switch 111A and the switchblade 135 being electrically interconnected by a lead 139 to the contact 132 of the starting switch 1 1 1A. However, when the timer means 82A is energized, the

switchblades

134 and 135 are respectively moved away from the contacts 136 and 137 to be placed in electrical contact with

contacts

140 and 141. The contact 140 is interconnected by a lead 142 to the stationary contact means 55A of the time delay switch means 53A while the contact 141 is interconnected by a lead 143 to one side 68A of the electrically operated means 67A of the vacuum pump 33A. The side 83A of the timer means 82A is interconnected by a lead 144 to the lead 138, while the other side 84A thereof is interconnected by a lead 145 to the power source L The power source lead 145 is also interconnected by a lead 146 to one side 147 of the ignition coil 117A, the other side 148 of the ignition coil 117A being interconnected by a lead 149 to a switchblade means 150 of the electrical switch 62A which is normally disposed in contact with the switchblade 61A and will follow movement thereof to the right until after the switchblade 61A makes contact with the switchblade 70A and will not break with the switchblade 61A until the switchblade 61A is further moved to the right by the bimetal member 123A that is interconnected to the switchblade 61A by the tieing means 125A.

The switchblade 61A carries the valve means 60A for controlling the opening 59A in the conduit means 58A.

The lead 149 is interconnected by a lead 151 to the other side 152 of the electrically operated means 67A of the vacuum pump 33A.

The movable switchblade 52A of the time delay switch means 53A is interconnected by a lead 153 to the contact 81A of the electrical motor 70'A. The contact 77A of the electrical motor 70 'A is interconnected by a lead 154 to the switchblade 61A of the electrical switch means 62A. In turn, the lead 154 is interconnected by a lead 155 to a stationary contact 156 of a motor starter relay means 157 that has a switchblade 158 normally disposed against the contact 156 and being electrically interconnected to the'contact 136 of the timer means 82A by a lead 159.

The operation of the control system 10A will now be described.

When the housewife or the like pushes in on the start button 114A, the switchblades 129 and 130 move into electrical contact with the contacts 131 and 132 and remain in contact therewith whereby the timer motor 82A is placed across the power source leads L, and L Before the now energized timer motor 82A moves the

switchblades

134 and 135 upwardly, it can be seen that the power source lead L is interconnected by the switchblade 134 of the timer means 82A to the contact 136, lead 159, switchblade 158, lead 155, and lead 154 to the starting and running windings 71A and 72A of the electric motor 'A so that the same are placed across the power source leads L, and L to cause operation of the motor 70'A whereby the centrifugally operated switch blade 79A is subsequently moved against the contact 81A so as to place the running winding 72A into electrical contact with the lead 153 of the time delay operated switch means 53A.

The timer means 82A moves the switchblades 134 and respectively against the contacts and 141 whereby the contact 81A of the electric motor 70'A is now efiectively interconnected to the power source lead L through the closed time delay switch means 53A and the side 68A of the vacuum pump 33A is now interconnected through the

switchblades

135 and 130 to the lead 133, and, thus, to the switchblade 70A of the switch means 62A. However, since the switchblade 70A is spaced from the switchblade 61A, the vacuum pump 33A is not energized at this time.

Since the power source lead L is, in effect, interconnected to contact 77A of the motor 70'A, by the closed time delay switch means 53A, the ignition coil 117A is effectively disposed across the power source leads L and L and the same begins to heat to ignition temperature. When the ignition coil 117A heats to ignition temperature, the bimetal member 123A warps to the right in FIG. 2 and moves the switchblade 61A therewith so that when the switchblade 61A engages the switchblade 70A, the side 68A of electrically operated means 67A of the vacuum pump 33A is now effectively interconnected to the power source lead L so that the vacuum pump 33A begins to operate and actuate the

actuators

22A, 23A and 24A to their open position so the fuel can now issue from the main burner means 124 and be ignited by the ignition means 117A in the manner previously described. 7

Since the switchblade of the switch means 62A follows rightward movement of the switchblade 61A until after the switchblade 61A makes contact with the switchblade 70A, both the vacuum pump 33A and the ignition means 117A are being energized at the same time for a short period of time whereby further movement of the bimetal member 123A to the right forces the blades 61A and 70A further to the right so that the switchblade 150 ceases to make contact with the switchblade 61A and terminates the energizing of the ignition means 1 17A.

By having the ignition means 117A and vacuum pump 33A operating together for a short period of time, this feature of this invention eliminates or minimizes the delay between the time that the vacuum pump 33A evacuates the

actuators

22A, 23A and 24A, permitting fuel to flow to the burner means 12A and the time that the current is removed form the ignition means 117A and the ignition means 117A begins to cool whereby the start point for the time delay means of the control system 10A is when the switch blade 150- recycle or restarting of the circuit A can take place in the event of a flame lockout wherein the burner means 12A fails to be ignited by the ignition means 117A.

In particular, an attempt to recycle the system 10A cannot take place once the pneumatically operated time delay means 46A has been actuated until the chamber 50A thereof returns to atmospheric condition, even though the ignition coil 117A may be reenergized to effect opening of the end 59A of the conduit 58A, as air will not be permitted to return to the chamber 50A any faster than the restrictor 128 will permit the air to return to the chamber 50A through the opened conduit 58A.

Another control system of this invention is generally indicated by the reference numeral 10B in FIG. 3 and parts thereof similar to the control previously described are indicated by like reference numerals followed by the reference letter B.

The pneumatic control part of the system 10B is substantially identical to that of FIG. 1 except that the conduit 58B has a resistor 128B therein in the same manner and for the same purpose as the resistor 128 of FIG. 2 previously described. In addition, the pneumatically operated

actuators

22B, 23B and 24B have restrictors 160 disposed respectively in the

conduits

36B, 37B and 388 so as to provide for a minimum sized orifice that leads to the chambers 28B of the

actuators

22B, 23B and 24B in the event of a diaphragm failure in any of the valve means 22B, 23B and 248 where fuel from the source 11B might enter the chamber 28B and be drawn into the pump 338. Thus, no adverse amount of raw gas can be directed by the pump 33B into the atmosphere upon diaphragm failure.

The control system 10B has the ignition control and safety switch arrangement 62B modified from that illustrated in FIG. 1.

In particular, the lead 69B from the pneumatic pump 33B is interconnected to a lead 161 that is interconnected to the power source lead means 65B, the leads 161 and 698 being joined together and to the lead 119B of the ignition coil means 117B that has its other lead 121B interconnected to the contact blade means 122B of the switch means 62B. The other side 66B of the electrically operated means 678 of the pneumatic pump 33B is interconnected by a lead 162 to the contact switchblade means 70B of the switch means 62B.

The movable blade means 52B of the switch means 53B is interconnected by a lead 163 to a switchblade means 164 of the switch means 628 which is interconnected by a tying means 165 to the blade 708 to move in unison therewith, the blade 164 normally being disposed in electrical contact with the switch blade means 166 of the switch means 62B that is interconnected by a lead 167 to the stationary contact 115B of the momentary start switch means 111B.

The stationary contact blade means 558 of the switch means 538 is interconnected by a lead 168 to the contact 77B of the electrical motor 70B as well as to a lead 169 that is interconnected to the blade means 86B of the timer means 82B as well as to one side of the timer means 82B.

The operation of the control system 10B will now be described.

As previously stated in connection with FIG. 1, when the manual start switch 1118 has its push button 114B depressed, an electrical circuit from power source lead L will flow through switch blade 1108, contact 1158 and lead 167 to contact blade 166 which is disposed in electrical contact with switchblade 164 and by lead 163 through the closed safety switch 53B to the motor 'B so as to place the motor 70B across the power source leads L and L for a start up thereof, the switchblade B remaining against the stationary contact B during the entire operation of the control system 10B and will be returned to the position illustrated in FIG. 3 by the timer means 823 at the end of cycle position thereof.

During start up, it can be seen that power source L is now effectively interconnected to lead 168 of the motor means 70B so that lead 169 interconnects power source L to switchblade 86B of the timer means 82B and, thus, to stationary contact 88B and through lead 90B, switchblade 61B and switchblade 122B to the side B of the ignition means 117B so that the ignition means 1178 is effectively placed across power source leads L and I. to begin to heat to ignition temperature which is sensed by the bimetal means 123B of the switch means 62B that is tied to switchblade means 61B by the tying means 125B previously described.

As the ignition means 117B reaches ignition temperature, the bimetal member 1238 of the switch means 62B will warp to the right in FIG. 3 breaking the ignition coil circuit in the manner previously described and energizing the pump 33B as the contact blade 61B is moved in to electrical contact blade 708 in the manner previously described. However, the transfer of the blade 613 from the blade 122B to the blade 70B could be a make-before-break arrangement in the same manner of FIG. 2, if desired, so that the vacuum pump 33B will be energized prior to the deenergizing of the ignition means 1 17B.

Therefore, the control system 10B continues to operate in the manner previously described for the system 10 of FIG. 1 until the timer means 828 terminates the operation thereof.

However, if the contact blade 61B should form a contact weld with the switchblade 703 when the bimetal member 1238 first moves the switchblade 61B to the right during initial start up because the ignition coil 1178 has reached ignition temperature and then the burner means 128 is not subsequently ignited for any reason so that the bimetal member 1238 begins to warp back to the left, such leftward movement of the contact welded together switchblades 61B and 708 will through the tying means carry the switchblade 164 therewith which will break contact with the switchblade 166 whereby the power source lead L will be effectively disconnected from the switch means 53B and, thus, form the motor means 70B so that the system 108 is completely shut down in the manner previously described and can not be restarted until the welded condition between the contact switchblades 61B and 70B is corrected.

Reference is now made to FIG. 4 wherein another control system of this invention is generally indicated by the reference numeral 10C and parts thereof similar to the systems previously described are indicated by like reference numerals followed by the reference letter C.

As illustrated in FIG. 4, it can be seen that the system 10C is somewhat similar to the system 10B previously described wherein the switch means 62C has the

additional blades

166C and 164C. However, the blade 166C is directly interconnected to the contact means 106C of the high limit safety switch construction 105C by a lead 170. The switch blade 110C of the start switch means 111C is interconnected by a lead 171 to the switch blade 87C of the timer means 82C and the contact 112C of the start means 111C is intercom nected by a lead 172 to the contact 81C of the motor means 70C, whereby the power source lead L during the operation of the control system 10C is directed to the contact 81C of the motor means 70 'C by the closed time delay switch means 53C when the switchblade 87C is against the contact 89C and the switchblade 110C is against the contact 112C.

Thus, it can be seen that if during the initial start up operation of the system 10C, the burner means 12C fails to ignite for some reason, the separating of the switchblade 164C from the switchblade 166C in the event of an adverse welded contact situation between the switchblades 61C and 70C in the manner previously described for the control system 10B of FIG. 3 cffectively disconnects the power source lead L from the contact 81C of the motor means 70C so as to terminate the operation of the control system 10C.

While the pneumatic control means for the burner means 12C are substantially the same as the pneumatic control means of FIG. 1 having the restrictions 160C of FIG. 3 in the conduit means 36C, 37C and 38C thereof a high limit vacuum control means 173 is provided for the control system 10C.

The high limit vacuum control means 173 comprises a conduit means 174 interconnected to the conduit means 40C and having an open end 175 controlled by a bimetal member 176 which will open the opening 175 when the temperature effect of the burner means 12C exceeds a preset high limit, the conduit 174 having a restriction 177 therein to prevent a shutting down of the control system 10C when only a momentary high temperature is reached. Thus, there would have to be a sustained high temperature period above the preset high limit to permit the atmosphere to bleed through the now open opening 175 of the switch means 173 and through the restrictor 177 into the chambers 28C of the

actuator

22C, 23C and 24C to terminate the flow of fuel to the burner means 12C.

Another control system of this invention is generally indicated by the reference numeral 100 in FIG. and parts thereof similar to the systems previously described are indicated by like reference numerals followed by the reference letter D.

As illustrated in FIG. 5, the switch means 62D has been modified from that illustrated in FIG. 4 by the adding of an ambient temperature compensating bimetal member 178 that is interconnected to the ignition sensing bimetal member 123D by a tying means 179.

In this manner, an increasing ambient temperature around the bimetal member 123D when no flames exist at the burner means 12D would cause the bimetal member 123D to warp to the right and transfer the switch means 62D. However, with the ambient compensating bimetal member 178, the bimetal member 178 will be warping to the left in the opposite direction of the bimetal member 123B upon an increase in ambient temperature resulting in no movement in the switch means 62D with changes in atmospheric temperatures.

The control system 10D includes a high temperature sensor and electrical switch means 180 wherein the bimetal member 176D that controls the opening 175D in the conduit means 174D previously described for the control system 10C of FIG. 4 also operates an electrical switch 181 having contact blades 182 and 183 respectively interconnected to

leads

184 and 185. The lead 185 is interconnected to the side 83D of the timer means 82D and the lead 184 is interconnected to lead D.

The movable contact means 55D of the pneumatically operated electrical switch 53D is interconnected by a lead 186 to the blade means D of the start switch means 111D.

According to this invention it has been discovered that the blower output temperature of a laundry dryer will, with a normal flame structure at the burner means, proceed at a given temperature until such time as the humidity in the output air has decreased to approximately 10 percent relative as the laundry becomes dri er. At this time, with the same burner setting, the output air temperature will undergo a stepped increase of an easily measured magnitude.

Thus, the purpose of the electrical switch means 180 is to sense the output air, such as by locating the bimetal member 176D in the output air chamber or duct. At such time as the stepped change is sensed, the bimetal member 176D will warp upwardly in FIG. 5 away from the opening D in the conduit means 174D and at the same time have its left hand end 187 warped downwardly to close the switchblade 182 against the switchblade 183.

As previously stated, opening of the end 175D of the conduit 174D will effect the actuator 24D to partially close the valve member 31D thereof to modulate the burner means 12D at a low flame level still controlled by the thermostatic means 42D in the manner previously described.

However, the closing of the switchblade 182 against the switchblade 183 will place the timer means 82D across the power source leads L and L where a timing cam means thereof will control the sequence of operation of the switchblades 86D and 87D so that both switchblades 86D and 87D are respectively disposed against the contact means 88D and 89D so that the system 10D will continue to function on the modulating low temperature flame for a given period of time. At the end of this time period, the switchblade 86D will open away from the contact 88D disconnecting the vacuum pump 33D from across the power source leads L and L so as to effectively shut down the burner means 12D while the switchblade 87D remains against the contact 89D and thereby continues to run the motor means 70'D achieving a tumbling of the clothes during the cool-down period. At the end of this time period, the second cam will open the switchblade 87D closing down the motor means 70'D and the entire system will be shut off in the manner previously described.

Another fuel control system of this invention is generally indicated by the reference numeral 10E in FIG. 6 and parts thereof similar to the other control systems previously described are indicated by like reference numerals followed by reference letter E.

As illustrated in FIG. 6, the control system E is substantially the same as the control system 10C of FIG. 4 with the following changes therein.

An additional contact 188 is added to the timer means 82D and is interconnected by a lead 189 to one side 190 of an environmental component 191, such as an ultraviolet lamp or something similar, having the other side 192 thereof interconnected to the lead 65E, the contact 188 of the timer means 82E adapted to be engaged by the switchblade 86E during burner shutdown and while the motor 70E and associated fan means are running on the cool-down cycle previously described in connection with the control system 10D of FIG. 5.

the flame sensing and ignition switch means 62E illustrated in FIG. 6 has been separated into two parts but the function thereof remains identical to the switch means 62C of FIG. 4 wherein the bimetal member 123E controls the switchblade 61E as well as another switchblade 61E that is electrically interconnected to the lead 90E as well as to a lead 193 that is interconnected to the switchblade 61E. Thus, when the bimetal member 123E senses that the ignition coil 117E is at ignition condition, the same through the tying means 125E and 125E moves the switchblades 61E and 61E to the right in FIG. 6 to disconnect the switchblade 61E from the switchblade 122E and place the switchblade 61E into electrical contact with the switchblade 70E for the purposes previously described, the switchblade 70E being tied to the switchblade 164E by the tying means 165E for the purpose previously described for the switch means 62C of FIG. 4 to protect against a welded contact situation between the contacts 61E and 70E.

The conduit 58E leading from the pneumatically operated time delay means 46E is interconnected by a branch conduit 194 to the pump inlet conduit means E, the conduit means 194 having a restriction 195 therein which performs the same function as the restriction means 57 of FIG. 1 whereby the actuator 46E is not actuated to open the switch means 53E as long as the end or opening 59E of the conduit means 58E is opened by the switchblade 61E. However, when the switchblade 61E is moved to the position illustrated in FIG. 6 after the main burner means 12E fails to ignite, the closing ofi of the opening 59E in the conduit 58E permits the vacuum in the evacuated lines and chambers of the system 10E to act through restriction 195 in the conduit 194 and actuate the actuator 46E to open the switch means 53E to terminate the cycle of operation in the manner previously described.

The conduit 174E has its open end 175E controlled by a pivotally mounted valve lever means 196 which has its pivot movement controlled by a humidity sensing element 197. With the opening 175E in the conduit 174E closed by the lever means 196 under the influence of the humidity sensor 197, a vacuum will build up in a chamber 198 of an actuator 199 that is interconnected to the conduit 174E by a branch conduit 200 whereby a flexible diaphragm 201 of the actuator 199 will be pulled downwardly in opposition to the force of a compression spring 202 to hold the switchblade 183E out of contact with the switchblade 182 in a manner similar to the switch means 181 of FIG. 5.

In particular, it can be seen that the switchblade 183E is interconnected by the lead 185E to the side 83E of the timer means 82E while the switchblade 182E is interconnected by the lead 184E to the lead E in a manner similar to the switch means 181 of FIG. 5.

Thus, it can be seen that the control system 10E of FIG. 6 functions similarly to the control system 10C of FIG. 4 wherein the ignition means 117E must first reach ignition condition before the pneumatic pump 33E is energized and at which time the time delay means 46E will terminate the operation of the system if the burner means 12E is not ignited within a predetermined time period after the ignition means 117E reached ignition temperature.

Similar to the cool-down operation of the control system 10D of FIG. 5, decreasing humidity in the output of the clothes dryer will affect the size of the opening 175E of the conduit 174E by the action of the humidity sensor 197 so that when the opening 175E is open, it will permit air to return to the chamber 198 of the actuator 199 whereby the diaphragm 201 is moved upwardly by the compression spring 202 to close the switchblade 183E against the switchblade 182E to initiate a low temperature drying cycle of the timer means 82E which will then function in the same manner as the timer means 82D of FIG. 5 previously described except that switchblade 86E can control the ultraviolet lamp 191 or other desired device during the operation of the control system 10E.

It should by noted that a manual shut-down switch means 203 is provided in the circuit means 63E of FIG. 6 complementing the manual start switch means 111E for permitting manual shut-down of the entire control system 10E at any time, the switchblade 204 of the shut-down switch 203 being electrically interconnected by a lead 205 to the switchblade 87E of the timer means 82E while a fixed contact 206 of the shut-down switch means 203 is interconnected by a lead 207 to the switchblade E of the start switch means 111E. In this manner, the switchblade 110E is effectively electrically interconnected to the switchblade 87E of the timer means 82E in the same manner as switchblade 110 of the system 10 of FIG. 1 during the normal operation of the control system 10E except that a person can push inwardly on the stop button means 208 to disconnect the switchblade 204 from the conduit contact 206, and thus, disconnect the motor means 70E from across the power source leads L and L Another control system of this invention is generally indicated by the reference 10F in FIG. 7 and parts thereof similar to parts of the systems previously described are indicated by like reference numerals followed by the reference letter F.

As illustrated in FIG. 7, the burner means 12F is interconnected to the fuel conduit means 11F by only two

actuators

23F and 24F as the first actuator 22 previously described has been eliminated.

The pneumatically operated time delay means 46 and safety switch means 53 of the other systems of FIGS. 1-6 have been eliminated from the control system 10F whereby the contact 89F of the timer means 82F is directly interconnected by a lead 210 to the switchblade 164F of the switch means 62F.

A pair of

bimetal members

211 and 212 are tied together by tying means 213 which also ties the

bimetal members

211 and 212 to the switchblade 166F. When a flame exists at the burner means 12F, bimetal member 212 will tend to warp toward bimetal member 211 and ratchet on the tieing means 213 thereby holding spring blade 166F in contact with the Switchblade 164F so that the motor means 70'F remains placed across the power source leads L and L. In the event that no flame is present at the burner means 12F, bimetal member 212 will not warp and an open circuit will result across the contact blades 164F and 166F.

Therefore, it can be seen that during initial start up of the system F, the ignition means 117F is placed across the power source leads L and L and when the same reaches ignition temperature, the bimetal member 123F moves to the right in FIG. 7 and interconnects the switchblade 61F to the switchblade 70F so as to energize the vacuum pump means 33F and open the

actuators

23F and 24F so that fuel can issue from the burner means 12F and be ignited by the ignition means 117F. However, during the heating up of the ignition means 117F, the bimetal member 212 ratchets on the tying means 213 to the left toward the bimetal member 211 without affecting movement of the switch blade 166F. If during a predetermined time period after the bimetal member 212 has ratcheted on the tying means 213 the main burner means 12F is not ignited, the cooling of the bimetal member 212 back to the right moves the tying means 213 back to the right to open the switch blade 166F away from the Switchblade 164F so as to terminate the operation of the motor means 70'F and thus the system 10F. However, if the burner means 12F is ignited, the flames at the burner means 12F maintain the bimetal member 212 to the left in FIG. 7, the bimetal member 211 being an ambient compensating bimetal for the sensing bimetal 212.

The control system 10F includes a set point adjustment means 214 for preselecting the desired temperature effect that is to be maintained by the thermostatic member 42F for the main burner means 12F, the set point adjustment means 214 comprising an adjustable valve member 216 controlling the effective size of an opening 217 in a branch conduit 218 that is interconnected to the conduit 40F. In this manner, the valve member 216 determines the bleed rate of air from a conduit 215 into the branch conduit 218 to set the temperature effect level that the bimetallic member 42F will maintain for the burner means 12F when it modulates the valve member 31F in relation to the temperature effect sensed by the member 42F in the manner previously described.

Therefore, it can be seen that each of the control systems of this invention provides the unique structure wherein the ignition means must first reach ignition temperature before the pneumatic source. creating device can be energized so as to shut down the system if the system is not properly operating after a predetermined time period.

What is claimed is:

1. In a fuel control system having pneumatically operated actuator means for interconnecting a fuel source to a burner means when a pneumatic source is interconnected to said actuator means, the improvement comprising an electrically operated pneumatic source creating device that only creates said pneumatic source when said device in interconnected to an electrical power source, said pneumatic source creating device comprising an electrically operated pneumatic pump, electrical ignition means for said burner means,

electrical circuit means operatively interconnected to said pump and to said ignition means, said circuit means only initially operating said pump by interconnecting said electrical power source thereto after said ignition means initially reaches ignition temperature, and time delay means for terminating the operation of said circuit means if said burner means is not ignited during a predetermined time period after said ignition means initially reaches ignition temperature, said circuit means operating said time delay means only after said ignition means reaches ignition temperature.

2. In a fuel control system as set forth in claim 1, said time delay means comprising a pneumatically operated electrical switch means in said circuit means.

3. In a fuel control system as set forth in claim 2, conduit means leading from said pneumatic pump to said pneumatically operated time delay means for tending to actuate the same when said pump is operated by said circuit means.

4. In a fuel control system having pneumatically operated actuator means for interconnecting a 'fuel source to a burner means when a pneumatic source is interconnected to said actuator means, the improvement comprising an electrically operated pneumatic source creating device, electrical ignition means for said burner means, electrical circuit means operatively interconnected to said device and to said ignition means, said circuit means only initially operating said device after said ignition means initially reaches ignition temperature, and time delay means for terminating the operation of said circuit means if said burner means is not ignited during a predetermined time period after said ignition means initially reaches ignition temperature, said circuit means operating said time delay means only after said ignition means reaches ignition temperature, said time delay means comprising a pneumatically operated electrical switch means in said circuit means, and conduit means leading from said pneumatic source creating device to said pneumatically operated time delay means for tending to actuate the same when said device is operated by said circuit means, said pneumatically operated time delay means having opening means interconnecting the same to the atmosphere to prevent operation thereof even if said device is operating and is interconnected thereto.

5. In a fuel control system as set forth in claim 4, a valve member for opening and closing said opening means, said valve member having its opening and closing movement controlled by said circuit means.

6. In a fuel control system as set forth in claim 5, said circuit means having electrical switch means which will operate said source creating device to actuate said actuator means only when said circuit means operates said ignition means to ignition temperature for igniting said burner means, said switch means carrying said valve member.

7. In a fuel control system as set forth in claim 1, said time delay means comprising condition responsive means which if the same does not sense an ignition condition at said burner means within said predetermined time period will terminate the operation of said circuit means.

8. In a fuel control system as set forth in claim 7, said condition responsive means comprising a bimetal operated electrical switch in said circuit means.

9. In a fuel control system as set forth in claim 1, said circuit means having electrical switch means which will operate said pneumatic pump to actuate said actuator means only when said circuit means operates said ignition means to ignition temperature for igniting said burner means.

10. In a fuel control system as set forth in claim 9, said switch means forming part of said time delay means.

11. In a fuel control system having pneumatically operated actuator means for interconnecting a source of fuel to a burner means when a pneumatic source is interconnected to said actuator means, the improvement comprising pneumatically operated time delay means for terminating the operation of said system when said actuator means is actuated, conduit means interconnecting said pneumatic source to said time delay means for actuating said time delay means, said time delay means having opening means for interconnecting the same to the atmosphere to prevent actuation of said time delay means even when said pneumatic source is interconnected thereto, electrically operated ignition means for said burner means, and valve means for opening and closing said opening means and having sensing means so as to open said opening means when said ignition means reaches ignition temperature.

12. In a fuel control system as set forth in claim 11, said sensing means of said valve means maintaining said valve means in its open position when sensing flame means at the ignited burner means.

13. In a fuel control system as set forth in claim 12, said sensing means comprising a bimetallic member.

14. In a fuel control system as set forth in claim 12, said pneumatic source comprising a vacuum source.

15. In a fuel control system as set forth in claim 11, said valve means having an electrical contact movable therewith.

16. In a method for operating a fuel burner means that has a source of fuel interconnected thereto when pneumatically operated actuator means is interconnected to a pneumatic source, the improvement comprising the steps of first energizing an electrical ignition means for said burner means to ignition temperature, thereafter, automatically creating said pneumatic source to actuate said actuator means by automatically turning on a pneumatic pump so that fuel can issue from said burner means and be ignited by said ignition means whereby said pneumatic source cannot be created until after said ignition means reaches ignition temperature, and automatically initiating the operation of a time delay means after said ignition means reaches ignition temperature so that if said burner means is not ignited within a predetermined time period the time delay means will terminate the operation of said burner means.

17. In a method as set forth in claim 16, said step of creating said pneumatic source comprising the step of electrically energizing said pneumatic pump.

18. In a method as set forth in claim 17, said step of creating said pneumatic source comprising the step of electrically energizing said pump by the closing of an electrical switch that senses the temperature of said ignition means.

9. In a method for operating a fuel burner means that has a source of fuel interconnected thereto when pneumatically operated actuator means is interconnected to a pneumatic source, the improvement comprising the steps of first energizing an electrical ignition means for said burner means to ignition temperature, thereafter, automatically creating said pneumatic source to actuate said actuator means so that fuel can issue from said burner means and be ignited by said ignition means whereby said pneumatic source cannot be created until after said ignition means reaches ignition temperature, and automatically initiating the operation of a time delay means after said ignition means reaches ignition temperature so that if said burner means is not ignited within a predetermined time period the time delay means will terminate the operation of said burner means, and automatically opening an opening in a pneumatically operated time delay means to prevent operation thereof when said ignition means reaches ignition temperature.

20. In a method as set forth in claim 19, said step of automatically creating said pneumatic source and said step of automatically opening said opening means being performed by the same element that senses the temperature of said ignition means.

Claims

1. In a fuel control system having pneumatically operated actuator means for interconnecting a fuel source to a burner means when a pneumatic source is interconnected to said actuator means, the improvement comprising an electrically operated pneumatic source creating device that only creates said pneumatic source when said device in interconnected to an electrical power source, said pneumatic source creating device comprising an electrically operated pneumatic pump, electrical ignition means for said burner means, electrical circuit means operatively interconnected to said pump and to said ignition means, said circuit means only initially operating said pump by interconnecting said electrical power source thereto after said ignition means initially reaches ignition temperature, and time delay means for terminating the operation of said circuit means if said burner means is not ignited during a predetermined time period after said ignition means initially reaches ignition temperature, said circuit means operating said time delay means only after said ignition means reaches ignition temperature.

3. In a fuel control system as set forth in claim 2, conduit means leading from said pneumatic pump to said pneumatically operated time delay means for tending to actuate the same when said pump is operated by said circuit means. 4. In a fuel control system having pneumatically operated actuator means for interconnecting a fuel source to a burner means when a pneumatic source is interconnected to said actuator means, the improvement comprising an electrically operated pneumatic source creating device, electrical ignition means for said burner means, electrical circuit means operatively interconnected to said device and to said ignition means, said circuit means only initially operating said device after said ignition means initially reaches ignition temperature, and time delay means for terminating the operation of said circuit means if said burner means is not ignited during a predetermined time period after said ignition means initially reaches ignition temperature, said circuit means operating said time delay means only after said ignition means reaches ignition temperature, said time delay means comprising a pneumatically operated electrical switch means in said circuit means, and conduit means leading from said pneumatic source creating device to said pneumatically operated time delay means for tending to actuate the same when said device is operated by said circuit means, said pneumatically operated time delay means having opening means interconnecting the same to the atmosphere to prevent operation thereof even if said device is operating and is interconnected thereto.

19. In a method for operating a fuel burner means that has a source of fuel interconnected thereto when pneumatically operated actuator means is interconnected to a pneumatic source, the improvement comprising the steps of first energizing an electrical ignition means for said burner means to ignition temperature, thereafter, automatically creating said pneumatic source to actuate said actuator means so that fuel can issue from said burner means and be ignited by said ignition means whereby said pneumatic source cannot be created until after said ignition means reaches ignition temperature, and automatically initiating the operation of a time delay means after said ignition means reaches ignition temperature so that if said burner means is not ignited within a predetermined time period the time delay means will terminate the operation of said burner means, and automatically opening an opening in a pneumatically operated time delay means to prevent operation thereof when said ignition means reaches ignition temperature.