US3088516A

US3088516A - Safety control device

Info

Publication number: US3088516A
Application number: US735790A
Authority: US
Inventors: Carmen L Marcellino; Walter P Palanker
Original assignee: A MORTON SHAPIRO
Current assignee: A MORTON SHAPIRO
Priority date: 1958-05-16
Filing date: 1958-05-16
Publication date: 1963-05-07
Anticipated expiration: 1980-05-07

Description

y 1963 c. 1.. MARCELLINO ETAL 3,088,516

SAFETY CONTROL DEVICE 2 Sheets-Sheet 1 Filed May 16, 1958 My mm mmm WMW n mm aw 2 M.\ urn. uixkk FM y 1963 c. MARCELLINO ETAL 3,088,516

SAFETY CONTROL DEVICE Filed y 16, 1958 2 Sheets-Sheet 2 SON'C AMPLIFIER c. Tmmsnucsa HLTER RE Hr-lea (v TRANSLSTOR L E Z AMPL\ FIER A Tram [xx United States Patent Office 3,088,516 Patented May 7, 1963 3,088,516 SAFETY CONTROL DEVICE Carmen L. Marcellino and Walter P. Palanker, Camden,

N.J., assignors of one-third to A. Morton Shapiro, Camden, NJ.

Filed May 16, 1958, Ser. No. 735,790 6 iliaims. (Cl. 158-28) The invention relates to a safety control device and more particularly a safety control device for monitoring the flame of a burner mechanism.

Heretofore safety control devices have been provided for monitoring the flame of a burner mechanism, which devices have operated inefliciently and have failed to take into account serious malfunctioning conditions of the burner mechanism.

It is therefore a principal object of the invention to provide a new and improved safety control device responsive to various malfunctioning conditions of a burner mechanism for terminating the operation of the mechanism.

Another object of the invention is to provide a new and improved safety control device having a high degree of efficiency for rapidly detecting malfunctions of a burner mechanism and terminating its operation.

Another object of the invention is to provide a new and improved safety control device for detecting both the absence of a flame or the improper combustion of a flame for terminating the operation of the burner mechanism.

Another object of the invention is to provide a new and improved safety control device for terminating the operation of a burner mechanism when the flame intensity exceeds a predetermined value.

Another object of the invention is to provide a new and improved safety control device adapted for utilizing either alight sensing cell or a compression wave detector such as a sonic transducer for determining the condition of the flame of a burner mechanism.

Another object of the invention is to provide a new and improved safety control device including a photo-electric cell mounting means for a burner mechanism.

The above objects as Well as many other objects of the invention are achieved by providing a safety control device comprising a flame sensing means for detecting the flame condition of a burner mechanism, and a control means connected with the sensing means and including a finst relay terminating the operation of the burner mechanism in the absence of a flame and a second relay terminating the operation of the burner mechanism when the flame of the burner mechanism exceeds a predetermined combustion rate.

The safety control device also includes a pair of thermal time delay relays connected in series with the actuating element of a holding circuit and positioned across a signal source, the delay relays when in their closed positions allowing the energization of the holding circuit which maintains the actuating element of the holding circuit energized. The first delay relay delivers power through the holding circuit contacts to the ignition system of the burner mechanism and terminates energization of the ignition system after a predetermined interval, while another pair of contacts of the holding circuit acts to continue driving the motor of the burner mechanism as long as the holding circuit is energized.

'Iihe sensing means may have the form of a photoelectric or photo-voltaic cell responsive to the light generated by the flame for controlling the operation of the control device and causing the termination of the operation of the burner mechanism when the flame condition indicates abnormal operation.

The sensing means may also have the form of a compression wave detector in the audio or supersonic range for detecting an abnormal condition of the flame by the amplitude and composition of frequencies generated by the flame of the burner mechanism.

The above objects of the invention as well as many other objects of the invention will become apparent when the following description is read together with the drawings, in which:

FIGURE i1 is a schematic view of a safety control device embodying the invention,

FIGURE 2 is a diagrammatic view in block form illustrating a sonic sensing means for the device shown in FIGURE 1, and

FIGURE 3 is a sectional view illustrating the mounting of a sensing means in a burner mechanism housing.

Like numerals refer to like parts throughout the several views.

FIGURE 1 is a schematic view of a safety control device 1d embodying the invention. The device Jill has a pair of input terminals 12 and 14 which are respectively connected to input lines 16 and 1-8. The terminals 12 and 14 are adapted to receive 117 volt AC. power for energizing the device 10. The line 16 is connected to the contact 20 of a thermal delay relay 22, while the line 18 connects the terminal 14 to ground potential.

The thermal delay relay 22 has a heating element 24 for activating a thermally responsive armature 26 which in its deenergized state normally engages the contact 20. The armature 26 disengages the contact 20 a predetermined period after its temperature has been increased by the energization of the heating element 24. The thermal delay relay 22 is of the type requiring a one to two minute delay to open the circuit between its contact 20 and armature 26.

A second thermal delay relay 28 may be identical to the thermal delay relay 22. The contact 30 of the delay relay 2 8 is connected with the armature 26 of the relay 22 and its armature 32 is connected to ground potential through the primary winding 34 of a transformer 36 of a holding circuit 38. The heating element 40 of the relay '28 is connected in series with the heating element 24 of the relay 22 and are bridged between a line 42 and ground potential.

One end of the secondary winding 42 of the transformer 36 is connected with a line 44, while its other end is joined to the terminal 46 of a thermostat 48.

The thermostat 48 comprises a contact 50' joined with the terminal 46 and a thermally responsive bimetallic element 52 which is positioned to engage the contact 50 at temperatures below a predetermined value. The armature 52 is connected to a terminal 54, so that a circuit is completed between the terminals 46 and 54 when the temperature sensed by the thermostat 48 is below a predetermined value.

The terminal 54 is connected by a line 56 with the armature S8 of a reset relay 6!). The armature 58 of the reset relay 60 normally engages a contact 62. When the reset relay 60 has its armature 58 in its open contact position, the energization of its actuating coil 66 moves its armature 58 into engagement with its contact 62. The actuating coil 66 of relay 60 is energized by the closing of the normally open push button switch 68 which closes a circuit from the line 16 through the winding of coil 66 to ground potential.

The contact 62 of the relay 61) is joined with the line 44 by the line 70 which is connected in series with the actuating coil 72 of the holding relay 74- of the circuit 38.

The first armature 76 of the holding relay 74 is connected with the line 16 and engages its contact 78 when the coil 72 is energized. The contact 78 is connected with the ungrounded end of the primary winding 34 of the transformer 36.

The second armature 80 of the relay 74 is also normally open and engages its contact 82 upon the energization of the actuating coil 72. The armature 80 of relay 74 is connected to the armature 26 of the delay relay 22 and the contact of the delay relay 28, while its contact 82 is returned to ground potential through the primary of an ignition transformer 84 of a burner mechanism 86. The secondary winding of the transformer 84 may be connected in the usual manner with a pair of electrodes 88 such as those commonly used in oil or gas burner mechanisms for igniting the fuel dispensed by the burner mechanism.

A third armature 90 of the holding relay 74 is also connected with the line 16 and engages its contact 92 when its actuating coil 72 is energized. The contact 92 is joined with line 42 for return to ground potential through the series connected

heating elements

40 and 24 respectively of the

delay relays

28 and 22, while also being returned to ground potential through the motor 94 of the burner mechanism 86. The motor 94 is of the usual type .utilized for providing a fuel pressure and may also be used for energizing a blower for mixing air in the proper proportions with the fuel to be burned. The burner mechanism 86 may be of the type known in the art, in which the motor 94 is continuously energized during the operation of the burner, while the electrodes 88 provide a spark for initially igniting the combustible mixture and after a predetermined period may have their operation terminated.

The line 44 is also connected to the cathode of a crystal diode 96 which has its anode returned through a charging capacitor 98 to the line 70.

The anode of diode 96 is also connected by a line 100 to one end of the actuating coil 102 of a control relay 104, while the other end of the actuating coil 102 is connected to a collector electrode 106 of a transistor 108. The transitsor 108 may be of the PNP type. The control relay 104 has a contact 110, and an armature 114 which is biased to engage contact 110 when the actuating coil 102 is deenergized. When the actuating coil 102 of the relay 104 is energized, the armature 114 disengages the contact 110.

An overload control relay 116 has its actuating coil 118 connected in parallel with the actuating coil 102 of the control relay 104. Thearmature 122 of the relay 1 16 normally disengages the contact 124 except when its actuating coil 118 is energized, at which time it engages its contact 124. Contact 124 connects to armature 114 and line 70.

The transistor 108 includes an emitter electrode 126 which is connected to the line 70, and a base electrode 128 which connects to an input terminal 130 through a variable resistor 132. The resistor 132 has an adjustable contact 134 with a shorting conductor 136.

A flame sensing means such as a photoelectric cell 136 is connected across the terminal 130 and a second input terminal 138 which is joined with the line 70. The photo-cell 136 may be of the photo-voltaic type generating a voltage signal responsive to the light intensity from the flame of the burner mechanism 86. Such a cell 136 may be a barrier selenium type.

The contact 110 of relay 104 and the armature 122 of relay 116 are connected to a line 140 which is joined to the heating element 142 of a normally open thermal delay control relay 144. The heating element 142 of relay 144 is connected between lines 140 and 44-, while its armature 146 is joined with the line 16. The armature 146 normally disengages its contact 148 except after a predetermined period of energization of its heating element 142. The time delay of the control relay 144 is preferably approximately three seconds. The contact 148 is connected to ground potential through the actuating coil 150 of a shuhofi relay 152.

The shut-oif relay has an armature 154 which may assume either a left or right position. The armature 154 of the relay 152 is mechanically linked with the armature 58 of the reset relay 60 so that the armature 58 engages its contacts 62 when the armature 154 is in its right position, and the armature 58 engages its contact 64 when the armature 154 is in its left position. Upon energization of its actuating coil 150, the relay 152 causes its armature 154 to assume its left position.

For the purpose of illustration, the safety control device 10 will be described in connection with a burner mechanism 86 of the oil burning type, although it may be utilized with a gas burner, acetylene torch, and other similar mechanisms for providing shut down of the mechanisms in the event of its malfunctioning for increasing the safety of operation of such devices.

Consider the safety control device 10 with its relays and contacts as shown in FIGURE 1. When the thermostat senses a temperature below a predetermined value, it closes the circuit between its terminals 46 and 54. With energization supplied to the input terminals 12, 14 and the delay relays 22 and 28 in their closed positions, energization is supplied to the input winding 34 of the transformer 36. Thereby, the secondary winding 42 of the transformer 36 energizes the actuating coil 72 of the holding relay 74 through the thermostat 48 and the reset relay 60.

The armatures of the holding relay 74 assume their closed or contacting positions as long as its actuating coil 72 remains energized. In this condition with the armature 76 closed the line 16 is connected directly with the primary winding 34 of the transformer 36 for maintaining the actuating coil 72 of the holding relay 74 in its energized condition irrespective of the conditions of the delaying relays 22 and 28.

The closed position of the armature of the holding relay 74 completes the circuit through contact 20 and armature 26 of the delay relay 22 in its closed condition to the ignition transformer 84 of the burner mechanism 86. This results in the generation of sparks by the elec trodes 88 for the initiation of combustion of the fuel dispensed by the burner mechanism 86.

The closing of the armature with the holding relay 74 in its energized condition, connects the line 16 with the line 42, thus, energizing the

heating elements

40 and 24 respectively of the delay relays 28 and 22. At the same time, the completion of the circuit between the lines 16 and 42 supplies power to the motor 94 initiating and continuing the operation of the burner mechanism 86 in dispensing fuel mixture for ignition by the electrodes 88.

After the holding relay 74 has been energized for approximately one to two minutes the heating element 24 of the delay relay 22 sufficiently raises the temperature of its armature 26 to cause it to disengage its contact 20. This results in the termination of energization of the ignition transformer 84 which has had more than ample time to initiate combustion of the fuel. The delay relay 28 operates substantially in the same manner as the relay 22, so that its armature 32 disengages its contact 30 at approximately the same time to prevent cnergization of the ignition transformer 84 through the contact 78 of the holding relay 74. However, it is noted that the motor 94 continues to be energized and allows the continued operation of the burner mechanism 86.

It is noted that the diode 96 and capacitor 98 form a rectifying circuit which is directly connected across the energizing coil 72 of the holding relay 74. Thus, the capacitor 98 provides a direct current voltage across it during the period of energization of the actuating coil 72.

If after the holding relay 74 is actuated, the burner mechanism 86 operates properly and fuel is ignited almost immediately, the photo-electric cell 136 generates a voltage which is delivered to the base electrode 128 of the transistor 108. The voltage delivered by the photo-electric cell 136 is such that it increases the conductivity between the emitter and collector electrodes 126, 106 of the transistor 108 with an increasing intensity of light generated by the flame of the burner mechanism 86. Since the control relay 104 is highly sensitive, requiring a low energizing current for its actuating coil 102, the presence of a flame which is detected by the photo-electric cell 136' allows it to become activated. This results in the disengagement of its armature 114 from its contact 110. However, should the flame fail to appear or become extinguished, the signal produced by the photo-electric cell 136 is insuflicient to allow the energization of the relay 104. This causes the armature 114 of relay 104 to remain in engagement with its contact 110 allowing the energization of the heating element 142 of the control delay relay 144. Unless the flame appears within approximately three seconds after such a failure, the heating element 142 raises the temperature of the temperature sensitive armature 146 to a sufiicient degree to cause it to engage its contact 148.

Closing the relay 144 results in the energization of the shut-ofi relay 152 which by its coupled arrangement with the reset relay 60 opens the circuit from the transformer winding 42 to the energizing coil 72 of the holding relay 74. This deenergizes the holding relay 74 terminating the operation of the burner mechanism 86.

The three second delay interval provided by the control delay relay 144 is sufliciently long to allow the burner mechanism 86 to ignite its flame under proper operating conditions, and short enough to provide almost immediate shut-off of the burner mechanism 86 in the event of failure of its combustible mixture to ignite Within the safety period. The delayed ignition of the combustible fuel is thereby prevented, which is especially important since such combustion may result in an explosion and ex-. tensive damage because of the presence of the unburned dispensed fuel.

In the case where the flame of the burner mechanism 86 is ignited Within the required period, energization of the heating element 142 of the delay relay 144 is terminated and the operation of the mechanism 86 continues.

Where the fuel mixture is improper resulting in a higher rate of combustion than is normal, the photo-electric cell 136 will generate proportionally greater output voltage. This will result in the passing of an increased current through the transistor 108. An overload relay 116 is actuated when the current through its actuating coil 118 is above a predetermined value corresponding to the said flame condition. At such time its armature 122 is activated to engage the contact 124 which similarly results in the energization of the heating element 142 of the control delay relay 144. After the required three second delay interval, the delay relay 144 is closed. This energizes the shut-oif relay 152 which operates to actuate the reset relay 60 for deactivating the holding relay 74 and terminating further operation of the burner mechanism. 86'.

The adjustable resistor 132 is utilized for setting the values for which the safety control device 18 will operate to terminate the operation of the burner mechanism 86.

It is noted that after the termination of operation of the burner mechanism 86 due to a failure, the system will not allow further operation unless the push button reset switch 68 is manually operated for resetting the relay 66. This prevents further automatic operation until proper remedial action has been taken by the supervisory personnel.

The delay relays 22, 28 also act to prevent the opercontacts 20, 38. Thereby, in the event of a failure due to a failure or after a normal burning operation, until a delay period of one to two minutes. This is the time necessary for their

armatures

26, 32 to have their temperatures sufficiently reduced to lose contact with their, contacts 20, 38. Thereby, in the event of a failure due to faulty ignition, the immediate ignition of the fuel saturated burner is prevented increasing the safety attained.

When the burner. mechanism 86 is operating properly, and the temperature sensed by the thermostat 48 is sufficiently raised, it opens the circuit between its contacts 46 and 54 terminating the energization of the holding relay 74 and ending the heating cycle of the burner mechanism 86. The thermostat 48 thus causes the starting and stopping of the burner mechanism 86 to appropriately control the burner mechanism 86 in accordance with the temperatures sensed.

Thus, the safety control device 10 operates both to terminate further operation of the burner mechanism 86 when it fails to produce a flame after it has been energized for a predetermined period as well as terminating [the operation of the burner mechanism 86 when the flame which is produced is abnormal, such as when the mixture is improper and the light intensity indicative thereof exceeds a predetermined value. Of course, the safety control device 10 may be provided with sensing means for determining other abnormal parameters of the generated flame as will be now described in connection with FIG- URE 2.

FIGURE 2 discloses a sensing means 160* comprising a sonic transducer 162 which may be positioned in the exhaust of a burner system immediately before the stack. The signal provided by the sonic transducer is delivered to an amplifier filter 164 which delivers its output to a signal rectifier 166. The signal from the rectifier 166 may be further amplified by a transistor amplifier 168 and delivered to its output leads 170, 172. The output leads 170, 172 may be connected to the terminals 138 respectively in FIGURE 1 in place of the photo-electric cell 136.

The flame of the burner mechanism 86 produces a characteristic audio compression wave or signal having a spectrum with certain frequency amplitudes which vary with the various conditions of the flame. Such wave signals are detected by the sonic transducer 162. The am plifier filter 164 has a selected frequency range which is utilized for determining the condition of the flame. It also operates to eliminate such frequencies which are not generated by the normal action of the flame but by other means which are independent of the operation of the sys- Item and would result in interference. The rectifier 166 produces a direct current signal corresponding to the amplitudes of the frequencies transmitted by the filter 164. This signal is delivered by the amplifier 168 to the

terminals

130, 138 of the safety control device 10 for its operation in the manner already disclosed in connect-ion with the photo-electric cell 136.

Thus if the flame fails to appear within the three second delay interval, the sonic waves within the range of the filter 164 are absent, so that a signal is delivered causing the device 10 to shut-down and prevent operation of the burner mechanism 86. Should the flame appear within the required time, then the sonic transducer 162 provides frequency signals which are passed by the filter 164 to the rectifier 166 which provides a signal allowing the burner 86 to continue its operation under the control of the thermostat 48. Should the flame produced by the mechanism 86 be abnormal, so that the frequencies generated do not correspond to that range which is passed by the filter 164 the burner mechanism 86 will likewise be shut-down. Should the amplitude of the frequencies detected by the transducer 162 and passed by the filter 164 exceed a predetermined normal value, the rectifier 166 will provide a signal of increased amplitude which will activate the overload relay 116, also causing the shut-down of the burner 86.

Although the transducer 162 has been described as detecting sonic frequencies, such device may be utilized for detecting supersonic frequencies which may be characteristic of the flame produced by the burner mechanism 86.

It is further noted that the operation of the safety control device 10 provides constant monitoring of the opera tion of the burner mechanism 86. Thesafety of the device is further increased, in that should there be a failure of the sensing means 136 or 160, the lack of production of the appropriate signal will result in the automatic shutdown at the burner mechanism 86. Thus the safety control device 10 not only monitors the burner device 86 but has a self-monitoring feature.

In this connection, the formation of soot or other such material in the combustion chamber and its ducts, which may cause dangerous obstructions, may be detected by the appropriate positionings of the flame sensing means. Thus if the formation of soot prevents the detection of the flame, the safety control device 10, as previously explained, will result in the termination of the operation of the burner mechanism 86 requiring supervisional action to allow the operation of the burner mechanism 86.

FIGURE 3 discloses a portion of a burner mechanism 86 including a blast tube or housing 180 having a sub stantially cylindrical wall structure and an opening 182 in its end 184. The opening 182 is provided to allow the production of a flame within the chamber of a furnace. The end 184 of the housing 180 may be inserted through an opening 186 formed in the wall 188 (shown in dashed lines) of a furnace. The walls 188 in accordance with customary practice may be made of refractory material.

Within the housing 186 an oil fuel line 190 is positioned with its spray nozzle 191 positioned approximate the opening 182 and behind a pair of electrodes 88. The electrodes 88 form a gap at their ends for producing sparks to ignite the discharged fuel emanating from the nozzle 191 of the oil line 190. The electrodes 88 may be positioned in parallel on each side of the oil fuel line 190 and provided with outer insulating tubes 192. The outer surfaces of the insulating tubes are engaged by a cross bar or bracket 194 for securing them with the oil line 190. The bracket 194 which is positioned near the opening 182 of the housing 190 behind the nozzle 191 of the oil line 190, supports a flame sensing means which may be the photo-cell 136. The support of the cell 136 in its position within the housing 180 and proximate the flame generated by the burner mechanism 86 is highly important. The housing 180 provides a protective shield preventing damage to the cell 136. Furthermore, the position within the housing 180 allows the means 136 to sense the generated flame without being within the furnace, but yet being in a direct path of the light radiating from the flame. At the same time, the mounting of the cell 136 in this manner prevents its being coated with foreign matter and soot. This, is especially true due to the draft of air which is forced through the blast tube housing 180 about the line 190 by the blower of the usual burner mechanism for providing proper combustion and flame formation. The blast of air which circulates about the sensing means 136, also acts to cool it, thus, allowing it to operate under highly satisfactory conditions.

While a few representative embodiments of the invention have been described and illustrated in detail, it is understood that the invention is capable of various modifications and applications, not departing essentially from the spirit thereof, which will become apparent to those skilled in the art.

What is claimed is:

1. A safety control device for use with a burner mechanism comprising, in combination, a flame sensing means for detecting predetermined flame conditions of a burner mechanism, a control unit connected with said sensing means including a first relay for terminating the operation of said burner mechanism in the absence of a flame, a second relay for terminating the operation of said burner mechanism in response to the flame of said burner mechanism exceeding a predetermined combustion rate, said first relay comprising an actuating coil, a contact, and an armature engaging the contact when the relay is deactivated; said second relay comprising an actuating coil, a contact, and an armamre engaging the contact when the relay is activated; means activating said first relay during the operation of said burner mechanism upon the'detection of a flame by said sensing means and activating said second relay during the operation of said burner when the flame of said burner mechanism exceeds a predetermined combustion rate; a delay relay connected with the contacts of said first and second relays for terminating the operation of said burner mechanism a predetermined time after the deactivation of said first relay or the activation of said second relay, said delay relay comprising a heating element, a contact and an armature normally disengaging said contact and engaging said contact a predetermined time after its heating element is energized, means connected with the heating element of said delay relay and completing a circuit for energizing said delay relay during the operation of said burner through either of the armatures of said first and second relays in engagement with its respective contact, a shut off relay for the burner mechanism having an actuating coil connected with the contact of said delay relay for energization, and an armature having first and second positions; the actuating coil of said shut off relay being energized by the completion of its circuit through the contact and armature of said delay relay; said shut olf relay upon energization actuating its armature to its second position to terminate the operation of said burner mechanism, a normally open reset switch having an open position and a closed position, a reset relay including an actuating coil connected with said reset switch for energization, and an armature having first and second positions; said reset relay being energized when said reset switch is placed in its closed position; the armature of said reset relay assuming its first position upon energization of said reset relay; the armature of said reset relay being coupled with the armature of said shut off relay so that the armature of said shut off relay assumes its first position when said reset relay is energized and the armature of said reset relay assumes its second position when said shut off relay is energized.

2. A safety control device for use with a burner mechanism comprising a flame sensing means for detecting the flame condition of a burner mechanism; a control unit connected with said sensing means and including a first relay for terminating the operation of said burner mechanism in the absence of a flame and a second relay for terminating the operation of said burner mechanism when the flame of said burner mechanism exceeds a predetermined combustion rate; said first relay of said control unit comprising an actuating coil, a contact, and an armature engaging the contact when the relay is deactivated; said second relay of said control unit comprising an actuating coil, a contact, and an armature engaging the contact when the relay is activated; and in which said control unit includes means activating said first relay during the operation of said burner mechanism upon the detection of a flame by said sensing means and activating said second relay during the operation of said burner when the flame of said burner mechanism exceeds a predetermined combustion rate; and a delay relay having an actuator connected with the contacts of said first and second relays for terminating the operation of said burner mechanism a predetermined time after the deactivation of said first relay or the activation of said second relay 3. The safety control device of claim 1 in which the actuator of delay relay comprises a heating element, a contact, and a thermally actuated armature normally disengaging its contact and engaging its contact a predetermined time after its heating element is energized; means connected with the heating element of Said delay relay and completing a circuit for energizing said delay relay during the operation of said burner through either of the armatures of said first and second relays in engagement with its respective contact.

4. The safety control device of claim 3 including a shut-off relay having an actuating coil connected with said delay relay for energization, and an armature having first and second positions; the actuating coil of said shut-01f relay being energized by the completion of its circuit through the contact and armature of said delay relay; said shut-off relay upon energization actuating its armature to its second position to terminate the operation of said burner mechanism.

5. A safety control device for use with a burner mechanism comprising a compression wave sensing means for detecting compression waves generated by the flame of a burner mechanism and providing an output signal proportional in intensity to the radiating intensity of the flame, a frequency filter receiving the output signal of said sensing means and providing an output signal proportional in intensity to the radiating intensity of a predetermined frequency range of the compression Waves generated by said flame, and a control unit connected with and responsive to the output signal delivered by said filter and including means for terminating the operation of said burner mechanism when the intensity of said signal exceeds a predetermined value.

6. A safety control device for use with a burner mechanism comprising a compression wave sensing means for detecting compression waves generated by the flame of a burner mechanism and providing an output signal proportional in intensity to the radiating intensity of the flame, a frequency filter receiving the output signal of said sensing means and providing an output signal proportional in intensity to the radiating intensity of a predetermined frequency range of the compression Waves generated by said flame, and a control unit connected with and responsive to the output signal delivered by said filter and including means for terminating the operation of said burner mechanism, said last named means terminating the operation of said burner mechanism except when the signal derived from said sensing means is within a predetermined normal range of values.

References Cited in the file of this patent UNITED STATES PATENTS 1,755,390 Fischer et a1 Apr. 22, 1930 2,216,556 McGrath Oct. 1, 1940 2,304,489 Wetzel Dec. 8, 1942 2,375,900 DeLancey May 15, 1945 2,510,265 Strobel June 6, 1950 2,630,167 Diehl Mar. 3, 1953 2,767,783 Rowell et a1 Oct. 23, 1956 2,771,942 Miller Nov. 27, 1956 2,807,758 Pinckaers Sept. 24, 1957 2,843,198 Beckett July 15, 1958

Claims

1. A SAFETY CONTROL DEVICE FOR USE WITH A BURNER MECHANISM COMPRISING, IN COMBINATION, A FLAME SENSING MEANS FOR DETECTING PREDETERMINED FLAME CONDITIONS OF A BURNER MECHANISM, A CONTROL UNIT CONNECTED WITH SAID SENSING MEANS INCLUDING A FIRST RELAY FOR TERMINATING THE OPERATION OF SAID BURNER MECHANISM IN THE ABSENCE OF A FLAME, A SECOND RELAY FOR TERMINATING THE OPERATION OF SAID BURNER MECHANISM IN RESPONSE TO THE FLAME OF SAID BURNER MECHANISM EXCEEDING A PREDETERMINED COMBUSTION RATE, SAID FIRST RELAY COMPRISING AN ACTUATING COIL, A CONTACT, AND AN ARMATURE ENGAGING THE CONTACT WHEN THE RELAY IS DEACTIVATED; SAID SECOND RELAY COMPRISING AN ACTUATING COIL, A CONTACT, AND AN ARMATURE ENGAGING THE CONTACT WHEN THE RELAY IS ACTIVATED; MEANS ACTIVATING SAID FIRST RELAY DURING THE OPERATION OF SAID BURNER MECHANISM UPON THE DETECTION OF A FLAME BY SAID SENSING MEANS AND ACTIVATING SAID SECOND RELAY DURING THE OPERATION OF SAID BURNER WHEN THE FLAME OF SAID BURNER MECHANISM EXCEEDS A PREDETERMINED COMBUSTION RATE; A DELAY RELAY CONNECTED WITH THE CONTACTS OF SAID FIRST AND SECOND RELAYS FOR TERMINATING THE OPERATION OF SAID BURNER MECHANISM A PREDETERMINED TIME AFTER THE DEACTIVATION OF SAID FIRST RELAY OR THE ACTIVATION OF SAID SECOND RELAY, SAID DELAY RELAY COMPRISING A HEATING ELEMENT, A CONTACT AND AN ARMATURE NORMALLY DISENGAGING SAID CONTACT AND ENGAGING SAID CONTACT A PREDETERMINED TIME AFTER ITS HEATING ELEMENT IS ENERGIZED, MEANS CONNECTED WITH THE HEATING ELEMENT OF SAID DELAY RELAY AND COMPLETING A CIRCUIT FOR ENERGIZING SAID DELAY RELAY DURING THE OPERATION OF SAID BURNER THROUGH EITHER OF THE ARMATURES OF SAID FIRST AND SECOND RELAYS IN ENGAGEMENT WITH ITS RESPECTIVE CONTACT, A SHUT OFF RELAY FOR THE BURNER MECHANISM HAVING AN ACTUATING COIL CONNECTED WITH THE CONTACT OF SAID DELAY RELAY FOR ENERGIZATION, AND AN ARMATURE HAVING FIRST AND SECOND POSITIONS; THE ACTUATING COIL OF SAID SHUT OFF RELAY BEING ENERGIZED BY THE COMPLETION OF ITS CIRCUIT THROUGH THE CONTACT AND ARMATURE OF SAID DELAY RELAY; SAID SHUT OFF RELAY UPON ENERGIZATION ACTUATING ITS ARMATURE TO ITS SECOND POSITION TO TERMINATE THE OPERATION OF SAID BURNER MECHANISM, A NORMALLY OPEN RESET SWITCH HAVING AN OPEN POSITION AND A CLOSED POSITION, A RESET RELAY INCLUDING AN ACTUATING COIL CONNECTED WITH SAID RESET SWITCH FOR ENERGIZATION, AND AN ARMATURE HAVING FIRST AND SECOND POSITIONS; SAID RESET RELAY BEING ENERGIZED WHEN SAID RESET SWITCH IS PLACED IN ITS CLOSED POSITION; THE ARMATURE OF SAID RESET RELAY ASSUMING ITS FIRST POSITION UPON ENERGIZATION OF SAID RESET RELAY; THE ARMATURE OF SAID RESET RELAY BEING COUPLED WITH THE ARMATURE OF SAID SHUT OFF RELAY SO THAT THE ARMATURE OF SAID SHUT OFF RELAY ASSUMES ITS FIRST POSITION WHEN SAID RESET RELAY IS ENERGIZED AND THE ARMATURE OF SAID RESET RELAY ASSUMES ITS SECOND POSITION WHEN SAID SHUT OFF RELAY IS ENERGIZED.