US3508850A - Pneumatically operated control system and method - Google Patents

Description

April 28, 1970 A. L. GOOD 5 PNEUMATICALLY OPERATED CONTROL SYSTEM AND METHOD Filed March 15, 1968 Sheets-Sheet l 2:2 I84 244 I50 '3 ,zoz) 1 2n 7| w s rm 78 2 1 6| 63 75 8| INVENTOR ARTHUR L. GOOD HIS ATTORNEYS April 28, 1910 A. L. GOOD 3,508,850

PNEUKATICALLY OPERATED CONTROL SYSTEM AND METHOD Filed March 15. 1968 5 Sheets-Sheet 3 IIO I04 \5! F165 106 95 ARTWLYHTSSOD HIS ATTORNEYS April 28, 1970 A. L. GOOD 3,

PNEUHATICALLY OPERATED CONTROL SYSTEM AND METHOD Filed March 15, 196B 5 Sheets-Sheet 3 INVENTOR ARTHUR L. GOOD [8| HIS ATTORNEYS April 28,, 1970 A. L- GOOD PNEUMATICALLY OPERATED CONTROL SYSTEM AND METHOD Filed March 15. 1968 5 Sheets-Sheet 4 236 237 INVENTOR 24| ARTHUR 1., 6000 HI 5 ATTORNEYS United States Patent 3,508,850 PNEUMATICALLY OPERATED CONTROL SYSTEM AND METHOD Arthur L. Good, Elkhart, Ind., assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Mar. 15, 1968, Ser. No. 713,370 Int. Cl. F23 /00 US. Cl. 4312 40 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a pneumatically operated control system for a fuel burning apparatus wherein pneumatically operated valve means are provided for controlling the flow of fuel to the main burner and pneumatithe ignition means for igniting the fuel issuing from the cally operated actuator means are provided for operating main burner means, the control system including means for automatically terminating the ignition means once a flame appears at the main burner and for turning off the control system should the main burner not be ignited during a predetermined time period.

This disclosure relates to a pneumatically operated control system for a fuel burning apparatus as well as to a method for pneumatically operating a fuel burning apparatus or the like.

It is well known that various pneumatically operated control systems have been provided for a washing apparatus, such as automatic laundry washing machines and dishwashers, wherein the entire cycle of operation thereof is controlled by a program means that is adapted to sequentially interconnect and disconnect a pneumatic source from a plurality of pneumatically operated actuators when the program means is being moved by a timer motor in order to provide a complete cycle of operation for the apparatus.

However, no such control means has been provided for a fuel burning apparatus, such as a laundry drying machine and the like.

Accordingly, it is a feature of this invention to provide a pneumatically operated control system for a fuel burning apparatus wherein the pneumatically operated control system can maintain the temperature effect of the burner means for the apparatus at a selected temperature effect and can have the cycle of operation thereof terminated in any suitable manner.

In particular, one embodiment of this invention provides a control system for a laundry drying machine or the like wherein pneumatically operated valve means control the flow of fuel to the main burner means and pneumatically operated actuator means controls the ignition means for the main burner means in such a manner that when the control system is activated, a pneumatic source is interconnected to the ignition means and to the valve means to operate the same in such a manner that the subsequently issuing fuel from the main burner means will be ignited by the operated ignition means. However, if the ignition means fails to ignite the main burner during a predetermined time period, the control system is rendered inoperative until the same is again turned on by the operator.

Accordingly, it is an object of this invention to provide a pneumatically operated control system for a fuel burning apparatus or the like, the control system of this invention 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 im- 3,508,850 Patented Apr. 28, 1970 proved method for operating a fuel burning apparatus or the like, the method of this invention having one or more of the novel features set forth above or hereinafter shown or described.

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

FIGURE 1 is a schematic view illustrating the control system of this invention.

FIGURE 1A is a fragmentary view illustrating the thermostatically operated air bleed means for the control system of FIGURE 1.

FIGURE 1B is a view similar to FIGURE 1A and illustrates the bleed means in an open condition thereof.

FIGURE 2 is a cross-sectional view illustrating the selector means for the control system of FIGURE 1.

FIGURE 3 is a view similar to FIGURE 2 and illustrates the selector means in an on position thereof.

FIGURE 4 is a cross-sectional view illustrating the pneumatically operated timing means for the control system of FIGURE 1.

FIGURE 5 is a view similar to FIGURE 4 and illustrates the timing actuator in another position thereof.

FIGURE -6 is a cross-sectional view illustrating the pneumatically operated ignition actuator for the control system of FIGURE 1.

FIGURE 7 is a view similar to FIGURE 6 and illustrates the ignition actuator in another operating position thereof.

FIGURE 8 is a view, partially in cross-section, illustrating the piezoelectric crystal means of the ignition assembly for the control system of FIGURE 1.

FIGURE 9 is a view similar to FIGURE 8 and illustrates the crystal means in another operating position thereof.

While the various features of this invention are hereinafter described and illustrated as being particularly adaptable to provide a control means or method for a laundry drying machine, 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 fuel burning apparatus as desired.

Therefore, this invention is not to be limited to only the embodiment 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 FIGURE 1, the control system of this invention is generally indicated by the refrence numeral 10 and is being utilized to control the operation of a main burner means 11 of a fuel burning laundry drying machine having its outer casing schematically illustrated and indicated by the reference numeral 12. The main burner 11 is adapted to be supplied fuel from a fuel source conduit means 13 interconnected to one side 14 of a pneumatically operated valve means 15 having its outlet side 15 interconnected to one side 16 of a pressure regulator means 17 by a conduit means 18.

The outlet side 19 of the pressure regulator means 17 is interconnected by a conduit means 20 to an inlet side 21 of another pneumatcially operated valve means 22 formed in substantially the same manner as the pneumatically operated valve means 15. The outlet side 23 of the pneumatically operated valve means 22 is interconnected by a conduit 24 to an inlet side 25 of another pneuematically operated valve means 26 formed in substantially the same manner as the pneumatically operated valve means 15 and 22. The outlet side 27 of the pneumatically operated valve means 26 is interconnected to a conduit means 28 that leads to the main burner means 11 in a conventional manner so as to provide proper fuel air mixture as is well known in the art.

As illustrated in FIGURE 1, the pneumatically operated valve means has an inlet chamber 29 disposed in fluid communication with the supply conduit 13 and is separated from an outlet chamber 30 by a valve seat 31 that is adapted to be opened and closed by a valve member 32 carried on a flexible diaphragm 33 that cooperates with the housing means 34 of the valve means 15 to define a chamber 35. A compression spring 36 is disposed in the chamber and is of suffiicent strength to normally maintain the valve member 32 against the valve seat 31 when the chamber 35 is at atmospheric condition to prevent fluid communication between the chambers 29 and 30 thereof so as to prevent fuel from flowing to the main burner means 11. However, when the chamber 35 is evacuated in a manner hereinafter described, the pressure differential acting across the diaphragm 33 will move the diaphragm 33 to the left in FIGURE 1 to open the valve seat 31 and permit fuel to pass from the chamber 29 into the chamber 30 so as to be fed to the main burner means 11 in a manner hereinafter described.

The pneumatically operated valve means 22 and 26 are formed in substantially the same manner as the previously described pneumatically operated valve means 15 and need not be further described except to state that the diaphragm defined chambers thereof, similar to the chamber 35 of the valve means 15, are respectively disposed in fluid communication with conduit means 37 and 38 for a purpose hereinafter described. Similarly, the chamber 35 of the pneumatically operated valve means 15 is disposed in fluid communication with the conduit means 39.

The control system 10 includes an electromagnetically driven vacuum pump 40 having the inlet side 41 thereof interconnected to a conduit means 42 and its outlet side interconnected to the atmosphere in any suitable manner. The electromagnetically driven pump 40 has an electrical coil 43 with one side 44 thereof being interconnected to an electrical lead 45 while the other side 46 thereof is interconnected to an electrical lead 47. The lead 47 is electrically interconnected to a fixed contact 48 of a manually operated electrical switch 49 that has movable contact blades 50 and 51 respectively cooperable with the contact 48 and another contact 52 while the blades 50 and 51 are respectively inter connected to terminals 53 and 54 that are interconnected to a conventional two prong plug 55 that can be plugged in to a conventional 110 volt AC current outlet to supply electrical current for the control system 10. For example, the plug 55 has its two prongs 56 and 57 respectively interconnected to the terminals 54 and 53 by leads 58 and 59.

The lead 58 is electrically interconnected by a lead 60 to a switch blade terminal 61 of a door operated electrical switch 62 while the contact 52 of the manually operated electrical switch 49 is interconnected by a lead 63 to another switch blade terminal 64 of the door operated switch 62.

A pair of switch blades 65 and 66 are electrically interconnected to the terminals 61 and 64 and are respectively cooperable with contact means 67 and 68 of the door operated switch 62, the switch blades 66 and 65 being interconnected together to move in unison by a tying means 69 that also operates a valve member 70 to move in unison with the blades 65 and 66. The valve member 70 is adapted to be moved against an open end 71 of a conduit means 72 to close the same from the atmosphere only when the door of the drying machine 12 is disposed in its closed position and is opened away from the end 71 of the conduit 72 when the door of the laundry machine 12 is in its open position for a purpose hereinafter described.

When the drying machine door is in its open position, the tying means 69 holds the switch blade 65 against the fixed contact 67 while holding the switch blade 66 out of electrical contact with the contact 68. Conversely,

when the laundry drying machine door is in its closed position, not only is the valve member 70 disposed against the end 71 of the conduit 72 to close the same, but also the switch blade 66 is moved into electrical contact with the contact 68 while the switch blade 65 is moved away from the contact 67 for a purpose hereinafter described.

The contact 67 of the door operated switch 62 is interconnected by a lead 73 to one side 74 of an illuminating lamp 75 while the other side 76 of the lamp 75 is interconnected by a lead 77 to the terminal 53. Thus, it can be seen that when the dryer door is in its open position, the door operated switch 62 places the lamp 75 across the receptacle prongs 56 and 57 to energize the lamp 75 for illuminating the interior, laundry-receiving compartment of the dryer. Conversely, when the door of the machine is disposed in its closed position, the lamp 75 is de-energized because the switch blade 65 is moved away from the contact 67.

An electrical motor 78 is provided for rotating the clothes tumbling drum or the like and has one side 79 thereof interconnected by a lead 80 to the lead 45 which has its other end interconnected to the Contact 68 of the door operated switch 62. The other side 81 of the motor 78 is interconnected by a lead 82 to the lead 47.

In this manner, when the dryer door is disposed in its closed position to cause the switch blade 66 to bridge the contacts 64 and 68, the housewife or the like can manually close the switch 49 in a manner hereinafter described to cause the switch blades 50 and 51 to move in unison by a tying means 83 to simultaneously bridge the contact 54 with ,the contact 52 and the contact 53 with the contact 48 so that not only is the motor 78 now placed across the prongs 56 and 57 of the plug 55 but also the coil 43 of the electromagnetically driven pump 40 is placed across the prongs 56 and 57 of the plug so that both the electric motor 78 and the pump 40 will be energized whereby the energized motor 78 will cause operation of the tumble carriage of the dryer and the now operating pneumatic pump 40 will provide a source of pneumatic fluid for operating the control system 10 which in the embodiment illustrated in the drawings will be a vacuum source.

The manually operated switch 49 previously described can comprise part of a manual selector means for the control system 10 that is generally indicated by the reference numeral 84 in FIGURES 2 and 3 which will now be described.

As illustrated in FIGURE 2, the selector means 84 comprises a housing means 85 adapted to be secured to a control panel 86 of the apparatus 12 in any suitable manner while having a control shaft means 87 projecting out of an opening 88 in the control panel 87 to be interconnected to a control knob means 89, the control shaft means 87 having a disc-like plate 90 at the right hand end thereof provided with apertures 91 respectively receiving projection 92 of an externally threaded adjusting member 93 therethrough whereby the threaded member 93 is adapted to be rotatable in unison with the control knob 89 while the control knob 89 is adapted to be axially movable relative thereto for a purpose hereinafter described.

The previously described switch blades 50 and 51 respectively have one end thereof fixed to the housing means 85 and are respectively interconnected to the terminals 53 and 54 previously described while the free ends 94 and 95 thereof respectively carry contacts 96 and 97 adapted to cooperate with the previously described contacts 48 and 52 carried by the housing means 85 and being electrically interconnected to terminals 98 and 99 that permit electrical connections to the previously described leads 47 and 63.

A pair of operating plungers or rods 100 and 101 are telescoped in suitable aligned openings 102, 103 and 104, 105 formed in wall means 106 and 107 of the housing means 85 so as to guide axial movement of the rods 100 and 101.

The right hand end of the rods 100 and 101 in FIG- URE 2 bear against the switch blades 94 and 95 While the left hand ends thereof are adapted to abut against a flat end surface 108 of the disc 90 of the control shaft 87. In this manner, when the control knob 89 is in its out position as illustrated in FIGURE 2, the natural bias of the switch blades 50 and 51 is to the left in FIG- URE 2 so as to hold the contacts 96 and 97 out of electrical engagement with the contacts 48 and 52 to provide an off condition of the switch 49 as illustrated in FIGURES 1 and 2. Conversely, when the housewife or the like moves the control knob 89 axially inward to its in position, the disc 90 is moved to the right as illustrated in FIGURE 3 and forces the plungers 100 and 101 also to the right in opposition to the natural bias of the switch blades 50 and 51 to place thre contacts 96 and 97 respectively into electrical engagement with the contacts 48 and 52 to provide an on condition whereby the electric motor 78 and pneumatic pump 40 are energized in the manner previously described and will remain energized until the control knob 89 is again disposed in its out position as illustrated in FIGURE 2 in a manner hereinafter described.

A valve member 109 is carried by the rods 100 and 101 to move in unison therewith, the valve member 109 comprising a resilient member having a first annular face or ridge 110 concentrically disposed around a second annular face or ridge 111, the ridges 110 and 111 each being adapted to seat against a flat valve surface 112 of the housing means 85 that is respectively interrupted by passage means or ports 113 and 114 forming part of tubular members or nipples 115 and 116 adapted to have flexible conduit means or the like telescoped over the same so as to be in fluid communication with the ports 113 and 114. For example, such valve member and valve seat arrangement 109, 112 is indicated by the reference numeral 117 in FIGURE 1 and a pair of conduit means 118 and 119 illustrated in FIGURE 1 leading to the valve arrangement 117 are respectively adapted to be disposed in fluid communication with the ports 113 and 114 illustrated in FIGURE 2 by being telescoped over the respective nipples 115 and 116 for a purpose hereinafter described.

Thus, it can be seen that when the control knob 89 is disposed in its out position as illustrated in FIG- URE 2, the ports 113 and 114 are directly interconnected to the atmosphere by the compartment 114' of the housing means 85 being interconnected to the atmosphere in any suitable manner, but when the control knob 89 is moved axially inwardly to its in position as illustrated in FIGURE 3, the valve member 109 is seated against the valve surface 112 in such a manner that the annular ridge 111 seals closed the port 114 not only from the atmosphere compartment 114, but also from the port 113 which is sealed closed from the atmosphere compartment 114 which is sealed closed from the atmosphere compartment 114 by the annular ridge or face 110. Accordingly, not only are the electrical contacts 96 and 97 of the selector means 84 placed into electrical contact with the contacts 48 and 52 in the manner illustrated in FIGURE 3 to energize the motor 78 and vacuum pump 40, but also the conduits 118 and 119 of FIGURE 1 are dead ended from each other and from the atmosphere for a purpose hereinafter described.

The selector means 84 includes a second valve means indicated by the reference numeral 120 in FIGURE 1 and comprising a tubular extension 121 on the wall 107 of the housing means 85 as illustrated in FIGURE 2 that terminates in a port 122 surrounded by an annular valve seat 123 that has its degree of openness to the atmospheric controlled by a flexible spider-like member 124 carried by the previously described externally threaded adjusting member 93. The externally threaded member 93 is threadedly disposed in an internally threaded tubular projection 125 projecting to the left of the wall 107 and being concentrically disposed about the valve seat 123 as illustrated. The port 122 in the tubular member 121 is fluidly interconnected to a tubular extension or nipple 126 by passage means 127 defined between the wall 107 and another wall means 128 of the housing means with the nipple means 126 being adapted to be fluidly interconnected to a conduit means 129 illustrated in FIGURE 1 with the conduit means 129 being disposed in fluid communication with the conduit means 28 of the pneumatically operated valve means 26 by a T-connector 130.

A porous filter member 131 is carried by the externally threaded member 93 of the selector member 84 and is indicated by the reference numeral 131 in FIG- URE 1, the filter member filling the tubular extension and being disposed against the spider member 124.

Accordingly, the housewife or the like can rotate the control knob 89 relative to the control panel 86 to any desired temperature setting for the apparatus 12 whereby the rotational position of the externally threaded member 93 relative to the internally threaded member 125 of the selector means 84 will produce a predetermined bow in the spider-like member 124 against an outer annular shoulder means 132 of the wall 107 to provide a predetermined restriction at the port 122 so that air is adapted to bleed through the porous filter material 131 into the port 122 and, thus, into the conduit 129 to control the degree of actuation of the valve means 26 in order to control the flow of fuel to the main burner means 11 in a manner hereinafter described.

Therefore, it can be seen that the valve means 120 of FIGURE 1, that is manually set by the selector means 84 in the manner previously described, is a manually operated air bleed means for controlling the pneumatically operated valve means 26 so as to set the temperature setting or effect of the main burner means 11 for the dryer 12. The remaining branch of the T-connector illustrated in FIGURE 1 is disposed in fluid communication with a conduit means 133 that leads to one branch of another T-connector 134. The T-connector 134 has one of its branches interconnected to a conduit 135 that leads to a thermostatically operated air bleed means 136 that is adapted to interconnect the conduit 135 to the atmosphere in a controlled manner and in proportion to the temperature effect of the burner means 11 being sensed by the thermostatically operated bleed means 136.

For example, reference is now made to FIGURES IA and 1B wherein the conduit 135 has a free end 137 opened to the atmosphere and is provided with an internal annular channel 138 spaced from the end 137 and receiving a cylindrical member 139 that is adapted to seal closed the conduit 135 from the atmosphere in the manner illustrated in FIGURE 1A when the temperature being sensed by the member 135, 139 is below a predetermined temperature. For example, the material of the conduit 135 and the material of the member 139 can be so selected and so constructed and arranged that the material 139 will expand at a lower rate than the rate of expansion of the member 135 as the temperatures thereof progressively increase so that when a certain temperature is reached, the member 139 no longer seals closed the conduit 135 so as to permit an air bleed between the atmosphere and the interior of the conduit 135 in the manner illustrated in FIGURE 1B.

Thus, it can be seen that the manually adjusted air bleed means 120 and the thermostatically operated air bleed means 136 of FIGURE 1 are so coordinated together that when the housewife sets the control knob 89 at a selected temperature setting thereof, the amount of atmosphere adapted to bleed into the chamber of the pneumatically operated valve means 26 is such that the same will cause the valve means 26 to lower the rate of flow of fuel to the burner means 11 if the temperature effect of the burner means 11 is above the selected temperature and to permit an increased flow of fuel through the valve means 26 to the burner means 11 when the temperature effect of the burner means 11 is below the selected temperature effect. In this manner, the valve means 26 is adapted to maintain the temperature effect of the burner means 11 at the selected temperature setting.

The remaining branch of the T-connector 134 is interconnected by a conduit 140 to one side 141 of a restrictor 142 while the other side 143 of the restrictor 142 is interconnected by a conduit 144 to a T-connector 145, the purpose of the restrictor 142 being hereinafter described.

One branch of the T-connector 145 is interconnected to the conduit 37 leading to the chamber of the pneumatically operated valve means 22 while the remaining branch of the T-connector 145 is interconnected to a conduit 146 that leads to another "l -connector 147.

The T-connector 147 has one of its branches connected to the conduit 39 that leads to the chamber 35 of the pneumatically operated valve means 15 while the remaining branch of the T-connector 147 is interconnected to a conduit 148.

The previously described conduit 42 that leads to the inlet side 41 of the vacuum pump 40 leads to one branch of a T-connector 149 that has one of its branches interconnected to the previously described conduit 118 that leads to the manually operated valve means 117. The remaining branch of the T-connector 149 is interconnected to a conduit 150 that leads to a capacitance tank or accumulator 151 that is also interconnected to a conduit 152 leading to a pneumatically operated timing actuator 153.

The timing actuator 153 of FIGURE 1 is illustrated in cross-section in FIGURES 4 and and comprises a cup-shaped housing member 154 having its open end 155 closed by a flexible diaphragm 156 having its outer periphery 157 secured between the open end 155 of the cupshaped housing member 154 and a second housing member 158 secured thereto in any suitable manner whereby the diaphragm 156 cooperates with the cup-shaped member 154 to define a chamber 159 therebetween. The inner periphery 160 of the flexible diaphragm 156 is interconnected to a plunger 161 that carries a spring retaining plate 162 to move in unison with the plunger 161. A compression spring 163 is disposed between the spring retainer 162 and the housing member 158 by having one end 164 bearing against the spring retainer plate 162 and the other end 165 bearing against the housing member 158 whereby the force of the compression spring 163 tends to maintain the flexible diaphragm 156 in the up position illustrated in FIGURE 4.

The closed end 166 of the cup-shaped housing member 154 has a fiat valve face 167 interrupted by a plurality of first passage means 168 concentrically disposed about a second set of passage means 169 interrupting the surface 167 and being concentrically disposed about a central aperture 170 telescopically receiving a valve stem 171. The valve stem 171 carries a first valve member 172 to move in unison with the stem 171 while being disposed in the chamber 159 and having an annular ridge or valve face 173 adapted to seat against the surface 167 in the manner illustrated in FIGURE 5 and close all of the passage means 168 and 169 from the chamber 159 for a purpose hereinafter described.

The valve stem 171 carries a second valve member 174 to move in unison with the valve stem 171 and is disposed on the other side of the closed end wall 166, the valve member 174 having an annular valve face or ridge 175 adapted to seat against the outside flat surface 176 of the closed end wall 166 in the manner illustrated in FIGURE 4 to seal the passage 169 from the exterior of the cup-shaped housing member 154.

Another housing member 177 is secured to the housing member 154 at the bottom wall 166 thereof and cooperates with the surface 176 to define a first annular chamber 178 disposed in fluid communication with the passage means 168 while being sealed from the passage means 169. The housing member 177 also defines a second chamher 179 adapted to be disposed in fluid communication with the passage means 169 while being sealed from the passage means 168 as well as from the chamber 178.

The housing member 177 has a tubular extension or nipple means 180 disposed in fluid communication with the chamber 179 and in the control system 10 of FIGURE 1 is disposed in fluid communication with a conduit means 182 leading to a T-connector 183. The T-connector 183 has one of its branches interconnected to the previously described conduit 119 leading to the manually operated valve means 117 while the remaining branch of the T-connector 183 is disposed in fluid communication with a conduit 184 for a purpose hereinafter described.

The cup-shaped housing member 154 has a tubular extension or nipple means 185 disposed in offset relation to the valve members 172 and 174 so as not to be controlled by the same while being adapted to interconnect a conduit 186, FIGURE 1, to the chamber 159 of the actuator 153 for a purpose hereinafter described.

While the nipple means 185 is illustrated in FIGURES 4 and 5 as having a restriction 187 therein, such restriction could be provided for the actuator 153 by a separate restrictor illustrated in FIGURE 1 by the reference numeral 188 for a purpose hereinafter described, it being understood that in the control system 10, the built-in restrictor 187 of the actuator 153 as illustrated in FIG- URES 4 and 5 can be utilized or a separate restrictor 188 as illustrated in FIGURE 1 and can be utilized for the purpose hereinafter described.

A diaphragm back-up plate means 189 is carried by the plunger 161 so as to move in unison with the diaphragm 156 relative to the cup-shaped housing 154, the back-up plate 189 being disposed in the chamber 159 and against the underside of the diaphragm 156.

A plurality of leaf like springs 190 are each carried by the back-up plate 189 by having one end 191 thereof received in a cooperating recess 192 of the back-up plate 189 and having an intermediate portion 193 thereof bowed over an abutment 194 of the back-up plate 189 while the other end 195 thereof bears against an annular shoulder 196 of the plunger 161 and projects radially inwardly therefrom so as to be engageable against the under surface 197 of a disc-like end 198 on the upper end of the valve stem 171.

Thus, when the chamber 159 of the actuator 153 is interconnected to the atmosphere, the force of the compression spring 163 pulls and holds the diaphragm 156 upwardly to the deactuated position illustrated in FIG- URE 4 whereby the inner ends 195 of the spring members 190 engage against the under surface 197 of the valve stem disc 198 to raise the valve stem 171 vertically up- Wardly until the valve member 174 seats against the valve surface 176 to seal the passage means 169 from the chamber 178 and, thus, from the conduit 182 while holding the valve member 172 away from the valve seat surface 167 so that the chamber 159 is disposed in fluid communication with the conduit 152.

Conversely, when the chamber 159 is interconnected to the vacuum source 40 by way of the conduit 152 in a manner hereinafter described, the evacuation of the chamber 159 results in a pressure differential across the diaphragm 156 that causes the diaphragm 156 and plunger 161 to move vertically downwardly from the position illustrated in FIGURE 4 to the position illustrated in FIGURE 5 in opposition to the force of the compression spring 153 until the inner ends 195 of the spring fingers 190 engage against an annular projection 199 on the valve member 172 and moves the valve member 172 and, thus, the valve stem 171 and valve member 174 vertically downwardly therewith until the valve member 172 seats against the valve surface 167 to seal the chamber 178 from the chamber 159 while moving the valve member 174 away from the valve surface 176 to interconnect the chamber 179 to the area under the valve member 172 through the passage means 169 whereby the chamber 178 of the housing member 177 is also now disposed in fluid communication with the chamber 179 as illustrated in FIGURE for a purpose hereinafter described.

The previously described conduit 186 of FIGURE 1 that leads from the nipple means 185 at the actuator 153 is interconnected to one branch of a T-connector 200. Another branch of the T-connector 200 is interconnected to a conduit 201 that leads to one side 202 of the previously described restrictor 188. The remaining branch of the T-connector 200 is interconnected by a conduit 203 to a T-connector 204 that has one branch thereof interconnected to the previously described conduit 72 that leads to the door operated valve member 70.

The remaining branch of the T-connector 204 is interconnected by a conduit 205 to another T-connector 206 that has one of the branches thereof interconnected by a conduit 207 to a humidity sensor 208 while the remaining branch of the T-connector 206 is interconnected by a conduit 209 to a high limit thermostatic air bleed means 210.

In particular, the high limit thermostatic bleed means 210 can be formed in substantially the same manner as the previously described thermostatic air bleed means 136 except that the high limit thermostatic bleed means 210 seals closed the conduit 209 from the atmosphere until the high limit thermostatic device 210 senses a temperature effect of the burner means 11 above a high safe limit thereof at which time the thermostatic device 210 fully interconnects the atmosphere to the conduit 209 for a purpose hereinafter described.

Similarly, the humidity sensor 208 normally seal the conduit 207 from the atmosphere but during a drying cycle of the apparatus 12 can be so constructed and arranged that as the humidity in the dryer decreases because of the progressive drying of the laundry therein, the humidity sensor 208 will subsequently open the conduit 207 to the atmosphere when the humidity of the dryer drops to a degree that would indicate that the laundry has been sufficiently dried. Of course, such humidity sensor 208 could be manually settable so that the housewife could have the apparatus 12 automatically terminate the operation in the manner hereinafter described when the laundry therein has been dried to the desired degree of doneness as set by the manually settable humidity sensor 208.

The previously described conduit 184 of the system of FIGURE 1 is interconnected to a T-connector 211 which has one of its branches interconnected to the previously described conduit 148 while the remaining branch of the T-connector 211 is interconnected by a conduit 212 to a pneumatically operated actuator 213 that is utilized in the system 10 to operate an ignition means, generally indicated by the reference numeral 214, for igniting fuel issuing from the main burner means 11 in a manner hereinafter described.

A pneumatically actuated actuator 213 is illustarted in cross-section in FIGURES 6 and 7 and comprises a cupshaped housing member 215 having its opened end 216 closed by a flexible diaphragm 217. In particular, the outer peripheral edge 218 of the flexible diaphragm 217 is secured to the open end 216 of the cup-shaped housing member 215 by another housing member 219 secured to the housing member 215 in any suitable manner. The inner peripheral edge 220 of the flexible diaphragm 217 is interconnected to a plunger 221 to move in unison with the diaphragm 217 with the plunger 221 being interconnected to a diaphragm back-up plate 222 carrying spring members 223 formed in the same manner as the spring member 190 previously described for the actuator 153.

The closed end wall 224 of the cup-shaped housing member 215 has an inner flat valve surface 225 and an outer flat valve surface 226 respective interrupted by a plurality of passage means 227 concentrically disposed about a central aperture 228 passing therethrough and telscopically receiving a Valve stem means 229 carrying a first valve member 230 in the chamber 231 defined between the diaphragm 217 and the cup-shaped housing member 215. The valve member 230 is attached to the valve stem 229 to move in unison therewith by a spider member 232 with the spider member 232 having recess means 233 out therein so as to prevent the spider member 232 from sealing closed the central aperture 228 in the bottom wall 224.

The valve member 230 has a pair of concentrically disposed annular ribs or valve faces 234 and 235 adapted to respectively seat against the valve surface 225 and seal closed the passages 227 from the chamber 231 when the valve member 230 is disposed in the position illustarted in FIGURE 7.

Another valve member 236 is carried by the valve stem 229 to move in unison therewith and is adapted to seat against the ouside valve surface 226 of the end wall 224 when disposed in the position illustrated in FIGURE 6 to seal closed the central aperture 228 from the exterior of the housing member 215 for a purpose hereinafter described.

Another housing member 237 is secured to the housing member 215 and is so constructed and arranged that the same defines an annular chamber 238 disposed in fluid communication with the passage means 227 while being sealed from the central aperture 227 and from another chamber 239 adapted to be disposed in fluid communication with the central aperture 228 in the end wall 224 While being sealed from the chamber 238.

The housing member 237 has a pair of tubular extensions or nipple means 240 and 241 respectively extending therefrom and disposed in fluid communication with the annular chamber 238. When the actuator 213 of FIG- URES 6 and 7 is utilized in the control system 10 of FIGURE 1, the tubular extension 241 is sealed closed from the atmosphere in any suitable manner and in the embodiment illustrated in FIGURES 6 and 7, a cap or closure member 242 is utilized to seal closed the tubular extension 241 from the atmosphere.

The other tubular extension 240 is interconnected to the previously described conduit 212 of FIGURE 1 for a purpose hereinafter described.

The housing member 237 has another tubular extension 243 disposed in fluid communication with the chamber 239 and in the system 10 illustrated in FIGURE 1 is disposed in fluid communication with a conduit 244 leading to a T-connector 245. A tension spring 246 is interconnected to the plunger 221 of the actuator 213 to always tend to pull the flexible diaphragm 217 upwardly to the position illustrated in FIGURE 6 so that when the chamber 231 of the actuator 213 is interconnected to the atmosphere, the diaphragm 217 is pulled vertically upwardly to the position illustrated in FIGURE 6 by the tension spring 246 whereby the inner ends 247 of the spring fingers 223 are adapted to engage against an under surface 248 of a disc end 249 of the stem means 229 to pull the same vertically upwardly therewith until the valve member 236 seats against the valve surface 226 to seal the aperture 228 and, thus, the chamber 231 from the chamber 239 while the valve member 230 moves away from the valve surface 225 to interconnect the chamber 231 to the chamber 238 and, thus, to the conduit 212 of FIGURE 1.

Conversely, when the chamber 238 of the actuator 213 is interconnected to the vacuum source 40 in a manner hereinafter described, the subsequent evacuation of the chamber 231 while in the condition of FIGURE 6 results in a pressure differential across the diaphragm 217, which causes the flexible diaphragm 217 to move vertically downwardly in the manner illustrated in FIGURE 7 until the inner ends 247 of the spring fingers 223 engage against an annular shoulder 250 on the spider member 232 of the stem means 229 to move the valve member 230 vertically downwardly and seal closed the passages 227 from the chamber 231 while moving the valve member 236 away from its valve seat surface 226 to interconnect the chamber 231 to the chamber 239 through the spider member 232 for a purpose hereinafter described.

The plunger 221 of the actuator 213 is interconnected to a movable arm means 251 of the ignition means 214 in any suitable manner so as to cause movement of the arm 251 in substantial unison with movement of the plunger 221 of the actuator 213. For example, the tension spring means 246 previously described can have a portion thereof directly interconnected to the arm 251 so as to provide a flexible connection between the plunger 221 and the arm 251 while causing the arm 251 to substantially follow movement of the plunger 221 while the remaining upper free end 252 of the tension spring 246 is fixed from movement in any suitable manner.

As illustrated in FIGURES 8 and 9, the ignition means 214 include a stationary frame member 253 having a cutout 254 therein which defines a circular slot end portion 255 receiving a roller 256 having an annular recess 257 therein receiving the edge of the frame 253 at the cutout end portion 255 so as to rotate relative thereto. The previously described actuating arm 251 has its left hand end 258 provided with outwardly extending ear means 259 that are pivotally interconnected to outwardly directed shaft means 260 of the roller 256 so that the arm 251, in effect, pivotally mounted to the frame 253 by the roller 256 which has its axis of rotation relative to the frame 253 fixed by the slot end means 255.

A piezoelectric crystal stack 261 is disposed in the cutout 254 and comprises a pair of piezoelectric crystals 262 and 263 disposed in axially aligned relation between a pair of pressure pads 264 and 265 projecting outwardly through open ends of a substantially cylindrical retaining member 266. An electrical terminal means 267 is disposed between the crystal means 262 and 263 and is electrically interconnected to a first electrode 268, FIG- URE 1, that defines a spark gap 269 with a second electrode 270 electrically interconnected to the frame 253 as illustrated in FIGURE 1 with the spark gap 269 being disposed adjacent the outlet end 271 of the main burner means 11 for a purpose hereinafter described.

Another roller 272 is disposed in the end 273 of the cutout 254 of the frame 253 with the roller 272 having an annular recess 274 therein receiving the edge of the cutout 273 so that the roller 272 is fixed for rotation in the frame 253. The pressure pad 265 of the crystal stack 261 has an outwardly directed substantially frusto-conical projection 275 being received in the annular recess 274 of the roller 272 whereby the pressure pad 265 bears against the roller 272 to move thereagainst in a manner hereinafter described.

A third roller 276 is disposed in the space between the fixed roller 256 and the pressure pad means 264 of the crystal stack 261 and has an annular recess 277 therein which receives an outwardly extending substantially frustoconical projection 278 of the pressure pad 264.

The actuator arm 251 has second ear means 279 extending adjacent the previously described ear means 259 and are interconnected to outwardly extending shaft means 280 of the roller means 276 so as to cause the roller means 276 to move in unison with the arm 251 while permitting the roller means 276 to roll against the pressure pad 264 as well as roll against the roller means 256, the axis of rotation of the roller 256 being offset below the axis of rotation of the roller 276 in the position of FIGURE 8 as well as below the longitudinal axis of the stack 261.

In this manner, when the plunger 221 of the actuator 213 is moved vertically downwardly in FIGURE 1 upon the actuation of the actuator 213 being interconnected to the vacuum source 40 in a manner hereinafter described, the arm 251 has its right hand end thereof pulled downwardly therewith while the left hand end 258 thereof pivots relative to the frame 253 on the shaft means 260 of the roller 256 whereby the roller 276 is moved substantially vertically downwardly in the manner illustrated in FIGURE 8 by rolling against the pressure pad 264 and the fixed roller 256 to cause a progressively increasing squeezing action on the crystal stack 261 which rocks therewith in the manner illustrated in FIGURE 9 so that the stresses in the crystal members 262 and 263 are altered by such compressing action and, in a manner well known in the art, causes a potential differential at the spaced electrodes 268 and 270 so that when the potential diiferential exceeds a predetermined degree, electrical sparking occurs across the spark gap 269 in such a manner that the electrical sparking is sufiicient to ignite fuel issuing from the outlet end 271 of the main burner means 11.

As the arm 251 is being pulled downwardly from the position illustrated in FIGURE 8 to the position illus trated in FIGURE 9 by the evacuated actuator 213, such electrical sparking at the spark gap 269 can occur more than once because of the continuing compressing action on the crystal means 262 and 263.

Conversely, when the actuator 213 is again interconnected to the atmosphere so that the tension spring 246 moves the plunger 221 upwardly and moves the actuator arm 251 upwardly from the position illustrated in FIG- URE 9 to the position illustrated in FIGURE 8, the crystal stack 261 is permitted to expand back to the condition illustrated in FIGURE 8 whereby such relieving of the compression force on the crystals 262 and 263 also causes an altering of the stresses thereof which will also produce a potential ditferential at the electrodes 268 and 270 for sparking at the spark gap 269.

As previously stated, the conduit 244 leading from the actuator 213 is interconnected to one branch of the T- connector 245. Another branch of the T-connector 245 is interconnected by a conduit 281 to the side 282 of the previously described restrictor 188. The remaining branch of the T-connector 245 of FIGURE 1 is interconnected by a conduit 283 to the atmosphere at the end 284 of the conduit 283.

However, the end 284 of the conduit 283 is received in a bracket means 285 which carries a bimetal member 286 at one end thereof that is adapted to sense a flame at the main burner means 211. The bimetal member 286 is attached to a plunger 287 movably carried by the bracket means 285 with the plunger 287 having a valve member 288 on the free end thereof adapted to close the end 284 of the conduit 283.

Since the plunger 287 is interconnected to the bimetal member 286, when no flame exists at the outlet end 271 of the main burner means 11, the bimetal member 286 assumes the position illustrated in FIGURE 1 whereby the valve member 288 is spaced from the end 284 Of the conduit 283 so that the conduit 283 is fully interconnected to the atmosphere. However, when fuel is burning at the end 271 of the main burner means 11, the bimetal member 286 is warped by the heat and moves the plunger 287 to the right in FIGURE 1 whereby the valve member 288 fully seats against the end 284 of the conduit 283 to seal the same from the atmosphere as long as fuel is burning at the outlet end 271 of the main burner means 11.

The operation of the control system 10 of this invention as illustrated in FIGURE 1 will now be described with the understanding that the various parts illustrated in detail in FIGURES 1A, 1B and 2-9 are functioning or will be functioning in the manner previously described.

After the housewife or the like has disposed wet laundry or the like into the dryer 12 and has closed the door thereof so that the door operated switch 62 will be moved from the position illustrated in FIGURE 1 to place the switch blade 66 against the contact 68 and move the switch blade 65 away from the contact 67 while moving the valve member 70 against the end 71 of the conduit 72 to close the same from the atmosphere, the housewife can turn on the control system 10 by manipulating the selector means 84 previously described.

In particular, the housewife can turn the control knob 89 to the desired temperature setting for the operation of the dryer 12 whereby the amount of atmosphere adapted to bleed through the valve means 120 will be set in the manner previously described. Thereater, the housewife or the like pushes axially inwardly on the control knob 89 from the position illustrated in FIG- URE 2 to the position illustrated in FIGURE 3 to place the contacts 96 and 97 into electrical contact with the contacts 48 and 52 to energize the main motor 78 for rotating the carriage carrying the wet laundry as well as for energizing the vacuum pump 40 which begins to evacuate atmosphere from the conduit 42. At the same time that the control knob 89 is moved inwardly to the position illustrated in FIGURE 3, it can be seen that the valve member 109 seals the ports 113 and 114 from each other as well as from the atmosphere so that the vacuum pump 40, through the conduit 150, will begin to evacuate the chamber 151 as well as the line 152 leading to the chamber 159 of the timer 153 because the timer 153 is disposed in the deactuated position illustrated in FIGURE 4. Since the actuator 153 is disposed in the position illustrated in FIGURE 4, no air is being removed from the control system beyond the actuator 153 by the pump 40 because the valve member 174 of the actuator 153 is sealing the chamber 159 from the chamber 179 leading to the conduit 182. Since the vacuum pump 40 at this time is only being required to evacuate a small conduit volume, the pressure differential now being created across the valve member 109 of the selector member 84 is sufiicient to maintain the valve member 109 in the position illustrated in FIGURE 3 in opposition to the force of the natural bias of the switch blades 50 and 51 tending to return the plungers 100 and 101 to the left whereby the housewife or the like can release the pushed in control knob 89 and the control knob 89 will remain in its pushed in condition of FIGURE 3 to maintain the control system 10 in its on condition.

As the chamber 159 of the actuator 153 is being evacuated, the flexible diaphragm 156 thereof is pulled radially downwardly from the position illustrated in FIGURE 4 to the position illustrated in FIGURE 5 to interconnect the chamber 178 with the chamber 179 as illustrated in FIGURE 5 whereby the vacuum pump 40 will begin evacuating the lines 184, 148, 146, 39 and 37 as well as the line 212 leading to the actuator 213 while the restrictor 142 prevents the bleed-in of air from the valve means 120 into the line 146 at a rate faster than could be handled by the vacuum pump 40.

Similarly, the restrictor 188 provides a controlled air bleed into the chamber 159 of the actuator 153 from the opened end 284 of the conduit 283 at a rate that does not cause complete deactuation of the actuator 153 until after a predetermined time period.

Thus, it can be seen that since the end 71 of the conduit 72 is closed by the valve member 70 and since the high limit thermostat 210 and humidity sensor 208 are respectively closing their conduits 209 and 207 to the atmosphere, no bleed-in of air takes place into the chamber 159 of the actuator 153 from the conduit 72 and devices 208 and 210 to deactuate the same from the position illustrated in FIGURE 5.

Since the vacuum pump 40 is now interconnected to the chamber 231 of the ignition actuator 213 while the same is disposed in the deactuated position illustrated in FIGURE 6, such progressively increasing evacuation of the chamber 231 causes the flexible diaphragm 217 thereof to be pulled vertically downwardly to the position illustrated in FIGURE 7 so that the arm 251 of the igniter 214 is also pulled vertically downwardly therewith to cause sparking at the spark gap 269 in the manner previously described.

At the same time that the ignition actuator 213 is being evacuated, the chambers of the valve means 15, 22 and 26 are also being evacuated by the pump 40 so that the same open to issue fuel from the source 13 to the main burnner means 11 to issue out of the open end 271 thereof to be ignited by the sparks being created at the spark gap 269.

When the ignition actuator 213 reaches the position illustrated in FIGURE 7, it can be seen that the chamber 231 thereof is now interconnected to the conduit 283 and if the ignition means 214 has not ignited the fuel issuing from the main burner means 11, the end 284 of the conduit 283 is still interconnected to the atmosphere so that the atmosphere can enter the chamber 231 and cause the actuator 213 to have its diaphragm 217 pulled vertically upwardly by the tension spring 246 to cause further sparking at the spark gap 269 in order to ignite the fuel issuing from the outlet end 271 of the burner means 11. When the actuator 213 returns again to the position illustrated in FIGURE 6, it can be seen that the chamber 239 is now disconnected from the chamber 231 and the chamber 231 is again interconnected to the vacuum pump 40 through the actuated actuator 153 which is in the position illustrated in FIGURE 5 to again cause actuation of the actuator 213.

Thus, the ignition actuator 213 can be actuated and deactuated a predetermined number of times in the above manner to cause sparking at the spark gap 269 and for igniting the fuel issuing from the outlet end 271 of the main burner 11. However, the restrictor 188 in FIGURE 1 is so selected that if the main burner means 11 is not ignited during a predetermined time period after the timer actuator 153 has been initially actuated to the position illustrated in FIGURE 5, sufficient air will now bleed through the restrictor 188 into the chamber 159 of the timer actuator 153 to cause deactuation thereof back to the position illustrated in FIGURE 4 so that the vacuum pump 40 will be disconnected from the valve means 15, 22 and 26 to close the same and terminate the flow of fuel to the main burner means 11 while at the same time causing sufiicient air to bleed into the conduit 118 to diminish the pressure differential across the valve member 109 of the selector means 84 so that the natural force of the spring blades 50 and 51 move to the left and break the electrical connection at the contacts 48 and 52 to turn off the control system so that no more unburned gas will issue from the burner means 11.

Thus, it requires another positive actuation of the selector means 84 by the housewife or the like to again attempt to initiate an ignition cycle of the system 10 in the manner previously described.

However, it is assumed that the ignition actuator 213 has caused ignition of the fuel issuing from the main burner means 11 before such predetermined time period has lapsed so that the actuator 153 remains in the actuated position illustrated in FIGURE 5 and the now heated bimetal member 286 causes the valve member 288 to close the end 284 of the conduit 283 so that no more air is bled into the actuator 153 to tend to deactuate the same.

Thus, the main burner means 11 continues to burn and when the temperature effect of the main burner means 11 begins to exceed the selected temperature effect, the thermostatically operated bleed means 136 permits more air to enter the conduit and be directed to the pneumatically operated valve means 26 so that the valve member thereof is moved closer to its valve seat to decrease the flow of fuel issuing into the main burner means 11 and, thus, to diminish the temperature effect being produced by the burner means 11. Conversely, as the temperature effect of the burner means 11 decreases below the selected temperature effect, the thermostatically operated bleed means 136 decrease the amount of air passing to the thermostatic valve 26 so as to increase the amount of fuel issuing from the main burner means 11.

Accordingly, the thermostatically operated bleed means 136 in combination with the manually set bleed means 120 causes modulation of the amount of fuel being passed to the main burner means 11 to thereby maintain the temperature elfect in the dryer at the selected temperature. Subsequently, the humidity sensor 208 begins to sense that the clothes are becoming dryer and dryer so that when the same reach the preselected degree of dryness thereof, the humidity sensor 208 will now bleed into the actuator 153 through the conduit 186 to deactuate the actuator 153 in the manner previously described to shut down the entire system by turning off the selector means 84 automatically as the pressure diiferential across the valve member 109 thereof decreases to such a degree that the switch blades 50 and 51 move the control knob 89 to its out and off position illustrated in FIGURE 2 whereby not only are the main motor 78 and vacuum pump 40 de-energized, but also the valve means 15, 22 and 26 move to their closed position under the force of their compression springs to terminate the flow of fuel to the main burner means 11.

Of course, if the humidity sensor 208 is not utilized, suitable timing means could be utilized to terminate the cycle of operation of the dryer 12 in a manner conventional in the art.

Also, if during the previously described operation of the dryer 12 the temperature effect of the main burner means 11 should run away so that an unsafe high limit temperature is reached, the high limit air bleed means 210 will open the conduit 209 to the atmosphere to cause deactuation of the actuator 153 in the manner previously described to completely turn oif the control system in the manner previously described.

In addition, should any break occur in the various conduits of the system so as to interconnect to the atmosphere thereto, such interconnection to the atmosphere will bleed air back to the valve means 15, 22 and 26 to cause automatic closing of the same and deactuation of the actuator 153 to terminate the operation of the control system 10 in the manner previously described so that at no time can a failure in the pneumatic control system produce an unsafe runway condition of the dryer 12.

Therefore, it can be seen that this invention not only provides an improved control systemfor a dryer or the like, but also this invention provides an improved method for operating a fuel burning apparatus or the like.

While the form of the invention now preferred has been disclosed as required by the statutes, other forms may be used, all coming Within the scope of the claims which follow.

What is claimed is:

1. A pneumatically operated control system for a fuel burning apparatus having burner means adapted to be interconnected to a source of fuel comprising a source of pneumatic fluid separate from said source of fuel, pneu matically operated ignition means for said burner means, interconnecting means for interconnecting said fuel source to said burner means, pneumatically operated valve means for controlling the flow of fuel from said fuel source to said burner means through said interconnection means, said pneumatically operated valve means preventing the flow of fuel to said burner means when disconnected from said pneumatic source and opening to interconnect said fuel to said burner means when interconnected to said pneumatic source, and means for substantially simultaneously interconnecting said pneumatic source to said pneumatically operated ignition means and to said pneumatically operated valve means to operate said ignition means and open said valve means so that said ignition means will ignite fuel issuing from said burner means.

2. A pneumatically operated control system as set forth in claim 1 wherein said pneumatically operated ignition means comprises a piezoelectric crystal sparking means for ignition fuel issuing from said burner means.

3. A pneumatically operated control system as set forth in claim 2 wherein said pneumatically operated ignition means comprises a pneumatically operated actuator operatively interconnected to said piezoelectric crystal sparking means for effecting the altering of stresses in said piezoelectric crystal sparking means to produce igmtlon sparking when said actuator is actuated.

4. A pneumatically operated control system as set forth in claim 3 wherein said actuator has means to automatically cause actuation and deactuation thereof in an alter.- nating manner when said pneumatic source is interconnected to said actuator.

5. A pneumatically operated control system as set forth in claim 4 wherein sensing means are provided for sensing the burning of fuel at said burner means, said sensing means being operatively interconnected to said actuator to terminate the operation of said actuator and, thus to terminate said ignition sparks when said sensing means senses fuel burning at said burner means.

6. A pneumatically operated control system as set forth in claim 1 wherein a timing means is provided and is operatively interconnected to said ignition means to terminate the operation of said ignition means after a predetermined time period if said burner means is not ignited during such time period.

7. A pneumatically operated control system as set forth in claim 6 wherein said timing means comprises a pneumatically operated actuator.

8. A pneumatically operated control system as set forth in claim '7 wherein said actuator is operatively interconnected to said pneumatically operated valve means to in terconnect said pneumatic source to said valve means when said actuator is actuated.

9. A pneumatically operated control system as set forth in claim 8 wherein sensing means are provided for sensing the burning of fuel at said burner means, said sensing means being operatively interconnected to said actuator to terminate the actuation of said actuator when said sensing means does not sense a flame at said burner means after a predetermined time period following the initial actuation of said actuator.

10. A pneumatically operated control system as set forth in claim 9 wherein said sensing means is fluidically interconnected to said actuator by passage means, said passage means having a restrictor therein for providing said predetermined time period.

11. A pneumatically operated control system as set forth in claim 1 wherein said pneumatically operated valve means comprises a thermostatically operated valve means for controlling the flow of fuel from said source thereof to said burner means.

12. A pneumatically operated control system as set forth in claim 11 wherein a manually adjustable bleed means is operatively interconnected to said pneumatically and thermostatically operated valve means to at least partially control the degree of pneumatic actuation thereof.

13. A pneumatically operated control system as set forth in claim 12 wherein a thermostatically operated bleed means is operatively interconnected to said pneumatically control the degree of pneumatic actuation thereof in relation to the temperature effect of said burner means sensed by said thermostatically operated bleed means.

14. A pneumatically operated control system for a fuel burning apparatus having burner means adapted to be interconnected to a source of fuel comprising a source of pneumatic fluid, pneumatically operated ignition means for said burner means, interconnecting means for interconnecting said fuel source to said burner means, a pneumatically operated valve means for controlling the flow of fuel from said fuel source to said burner means through said interconnection means, means for interconnecting said pneumatic source to said pneumatically operated ignition means and to said peumatically operated valve means to operate said ignition means and said valve means so that said ignition means will ignite fuel issuing from said burner means, said pneumatically operated valve means comprising a thermostatically operated valve means for controlling the flow of fuel from said source thereof to said burner means, a manually adjustable bleed means being operatively interconnected to said pneumatically and thermostatically operated valve means to at least partially control the degree of pneumatic actuation thereof, and a thermostatically operated bleed means being operatively interconnected to said pneumatically and thermostatically operated valve means to control the degree of pneumatic actuation thereof in relation to the temperature effect of said burner means sensed by said thermostatically operated bleed means, said thermostatically operated bleed means having a fixed temperature setting thereof and said manually operated bleed means selecting the operating temperature effect for said burner means.

15. A pneumatically operated control system for a fuel burning apparatus having burner means adapted to be interconnected to a source of fuel comprising a source of pneumatic fluid, pneumatically operated ignition means for said burner means, interconnecting means for interconnecting said fuel source to said burner means, a pneumatically operated valve means for controlling the flow of fuel from said fuel source to said burner means through said interconnection means, means for interconnecting said pneumatic source to said pneumatically operated ignition means ad to said pneumatically operated valve means to operate said ignition means and said valve means so that said ignition means will ignite fuel issuing from said burner means, and a high limit thermostatically operated bleed means operatively interconnected to said pneumatically operated valve means to terminate the operation of said burner means when said high limit thermostatically operated bleed means senses an unsafe temperature effect of said burner means.

16. A pneumatically operated control system for a fuel burning apparatus having burner means adapted to be interconnected to a source of fuel comprising a source of pneumatic fluid, pneumatically operated ignition means for said burner means, interconnecting means for interconnecting said fuel source to said burner means, a pneumatically operated valve means for controlling the flow of fuel from said fuel source to said burner means through said interconnection means, means for interconnecting said pneumatic source to said pneumaticall operated ignition means and to said pneumatically operated valve means to operate said ignition means and said valve means so that said ignition means will ignite fuel issuing from said burner means, and a humidity operated bleed mean operatively interconnected to said pneumatically operated valve means to terminate the operation of said burner means when said humidity operated bleed means senses a predetermined humidity condition caused by said burner means.

17. A pneumatically operated control system as set forth in claim 1 wherein said source of pneumatic fluid comprises a vacuum producing pump.

18. A pneumatically operated control system as set forth in claim 1 wherein said control system comprises a control system for a laundry drying apparatus.

19. A pneumatically operated control system as set forth in claim 1 wherein a selector means is provided and is operatively interconnected to said pneumatically operated valve means to interconnect said pneumatic source to said valve means when set in one position thereof and to disconnect said source from said valve means when set in another position thereof.

20. A pneumatically operated control system as set forth in claim 19 wherein said selector means has means for causing automatic movement thereof to said other position thereof when a sensing means senses that the operation of said system should be terminated.

21. A method for pneumatically operating a fuel burning apparatus having burner means adapted to be interconnected to a source of fuel comprising the steps. of providing a source of pneumatic fluid separate from said source of fuel, providing pneumatically operated igni tion means for said burner means, providing pneumatically operated valve means for controlling the flow of fuel from said fuel source to said burner means, said pneumatically operated valve means preventing the flow of fuel to said burner means when disconnected from said pneumatic source and opening to interconnect said fuel to said burner means when interconnected to said pneumatic source, and substantially simultaneously interconnecting said pneumatic source to said pneumatically operated ignition means and to said pneumatically operated valve means to operate said ignition means and open said valve means so that said ignition means will ignite fuel issuing from said burner means.

22. A method as set forth in claim 21 wherein said step of pneumatically operating said ignition means includes the step of causing electrical sparking from a piezoelectric crystal sparking means so that said electrical sparks will ignite fuel issuing from said burner means.

23. A method as set forth in claim 22 wherein said step of causing said electrical sparking from said piezoelectric crystal sparking means comprises the step of altering the stresses in said piezoelectric crystal sparking means by actuating a pneumatically operated actuator operatively interconnected to said piezoelectric crystal sparking means.

24. A method as set forth in claim 23 wherein said step of altering the stresses in said piezoelectric crystal sparking means comprises the step of actuating and deactuating said actuator in an alternating manner when said pneumatic source is interconnected to said actuator.

25. A method as set forth in claim 24 and including the step of sensing the burning of fuel at said burner means with sensing means, and terminating the operation of said actuator and, thus, terminating said ignition sparks when said sensing means senses fuel burning at said burner means.

26. A method as set forth in claim 21 and including the step of terminating the operation of said ignition means after a predetermined time period by a timing means if said burner means is not ignited during such time period.

27. A method as set forth in claim 26 and including the step of pneumatically operating said timing means.

28. A method as set forth in claim 27 and including the step of interconnecting said pneumatic source to said pneumatically operated valve means only when said pneumatically operated timing actuator is actuated.

29. A method as set forth in claim 28 and including the step of sensing the burning of fuel at said burner means with sensing means, and terminating the actuation of said pneumatically operated timing atcuator when said sensing means does not sense a flame at said burner means after a predetermined time period following the initial actuation of said pneumatically operated time actuator.

30. A method as set forth in claim 29 and including the step of fluidically interconnecting the sensing means of said pneumatically operated timing actuator by a passage means having a restrictor therein that provides said predetermined time period.

31. A method as set forth in claim 21 and including the step of thermostatically operating said pneumatically operated valve means to control the flow of fuel from said source thereof to said burner means in relation to temperature sensed.

32. A method as set forth in claim 31 and including the step of manually adjusting a bleed means that is operatively interconnected to said pneumatically and thermostatically operated valve means to at least partially control the degree of pneumatic actuation thereof.

33. A method as set forth in claim 32 and including the step of thermostatically operating bleed means that is operatively interconnected to said pneumatically and thermostatically operated valve means to control the degree of pneumatic actuation thereof in relation to the 19 temperature affect of said burned means sensed by said thermostatically operated bleed means.

34. A method for pneumatically operating a fuel burning apparatus having burner means adapted to be interconnected to a source of fuel comprising the steps of providing a source of pneumatic fluid, providing pneumatically operated ignition means for said burner means, providing pneumatically operated valve means for controlling the flow of fuel from said fuel source to said burner means, interconnecting said pneumatic source to said pneumatically operated ignition means and to said pneumatically operated valve means to operate said ignition means and said valve means so that said ignition means will ignite fuel issuing from said burner means, thermostatically operating said pneumatically operated valve means to control the flow of fuel from said source thereof to said burner means in relation to temperature sensed, manually adjusting a bleed means that is operatively interconnected to said pneumatically and thermostatically operated valve means to at least partially control the degree of pneumatic actuation thereof, and thermostatically operating bleed means that is operatively interconnected to said pneumatically and thermostatically operated valve means to control the degree of pneumatic actuation thereof in relation to the temperature effect of said burner means sensed by said thermostatically operated bleed means, said thermostatically operated bleed means having a fixed temperature setting thereof and the manual adjustment of said manually operated bleed means selecting the operating temperature effect for said burner means.

35. A method for pneumatically operating a fuel burning apparatus having burner means adapted to be interconnected to a source of fuel comprising the steps of providing a source of pneumatic fluid, providing pneumatically operated ignition means for said burner means, roviding pneumatically operated valve means for controlling the flow of fuel from said fuel source to said burner means, interconnecting said pneumatic source to said pneumatically operated ignition means and to said pneumatically operated valve means to operate said ignition means and said valve means so that said ignition means will ignite fuel issuing from said burner means, and terminating the operation of said burner means by a high limit thermostatically operated bleed means sensing an unsafe temperature effect of said burner means.

36. A method for pneumatically operating a fuel burning apparatus having burner means adapted to be interconnected to a source of fuel comprising the steps of providing a source of pneumatic fluid, providing pneumatically operated ignition means for said burner means, roviding pneumatically operated valve means for controlling the flow of fuel from said fuel source to said burner means, interconnecting said pneumatic source to said pneumatically operated ignition means and to said pneumatically operated valve means to operate said ignition means and said valve means so that said ignition means will ignite fuel issuing from said burner means, and terminating the operation of said burner means when a humidity operated bleed means senses a predetermined humidity condition caused by said burner means.

37. A method as set forth in claim 21 wherein said source of pneumatic fluid is provided by operating a vacuum producing pump.

38. A method as set forth in claim 21 wherein said control system comprises a control system for a laundry drying apparatus.

39. A method as set forth in claim 21 and including the step of moving a selector means from one position thereof to another position thereof to interconnect said pneumatic source to said valve means, and moving said selector means from said other position back to said one position thereof to disconnect said source from said valve means.

40. A method as set forth in claim 39 and automatically causing movement of said selector means from said other position thereof back to said one position thereof when a sensing means senses that the operation of said system should be terminated.

References Cited UNITED STATES PATENTS 3,172,456 3/1965 Glasgow et a1 431255 3,344,835 10/1967 Hodgson 431255 3,384,071 5/1968 Body et a1 126273 X EDWARD G. FAVORS, Primary Examiner US. Cl. X.R.

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