Title:
ROTARY GAS CONTROL WITH A THERMOELECTRIC IGNITION SAFETY DEVICE AND PIEZOELECTRIC IGNITER
United States Patent 3770363
Abstract:
A rotary gas control apparatus has a rotary handle adapted for rotation from a gas-off position via an ignition stand-by position into a gas-on position. By the motion of the rotary handle, a piezo-electric ignition device with an impact mechanism is energized. In the ignition stand-by position, the rotary handle may be depressed, whereby a safety valve is opened and gas is allowed to flow to a pilot burner. In the depressed position, the handle is rotatable from the ignition stand-by position through a limited angle to an ingition position, whereby the ignition device is triggered and the pilot burner is lit thereby. A magnet thermoelectrically energized by the pilot burner holds the safety valve open. The handle is returned to the ignition stand-by position, moved outward and can now be rotated to the gas-on position, in which a main gas valve opens to permit the flow of gas to a main burner.
US Patent References:
ROTARY GAS SWITCH,IN PARTICULAR FOR WATER HEATERS
Schueler - December 1970 - 3550603
/3676041.html
Mobus - July 1972 - 3676041
/3676047.html
Shinichi Soma - July 1972 - 3676047
ROTARY GAS SWITCH,IN PARTICULAR FOR WATER HEATERS
Schueler - December 1970 - 3550603
/3676041.html
Mobus - July 1972 - 3676041
/3676047.html
Shinichi Soma - July 1972 - 3676047
Application Number:
05/222564
Publication Date:
11/06/1973
Filing Date:
02/01/1972
View Patent Images:
Export Citation:
Assignee:
Joh. Vaillant KG (Remscheid, DT)
Primary Class:
Other Classes:
431/255
International Classes:
F23Q9/08; F23Q9/14; F24C3/10; F24C3/12; F23Q9/00; F24C3/00; F23Q7/12
Field of Search:
431/47,43,255
Primary Examiner:
Dority Jr., Carroll B.
Claims:
What I claim is
1. In a rotary gas control having a thermoelectric safety device comprising valve means including a safety valve, rotary handle means connected to said valve means and rotatable from a gas-off position first to an ignition stand-by position and then into a gas-on position, a piezoelectric ignition device, an impact mechanism for said device means connecting the handle means and the impact mechanism for actuating the mechanism to impact on the device upon movement of the handle, the improvement comprising:
2. In a gas control apparatus comprising a housing member on which is mounted a piezoelectric ignition element, a pilot valve, a main burner valve, a safety valve between a gas inlet and the pilot and main burner valves, valve actuating means operatively connecting the valves and including a movable handle for maintaining all of said valves closed at a first rotational position, for opening the pilot valve at a second rotational position in a given rotational direction from said first position, for opening said safety valve after axial movement of the handle at said second rotational position to an axially displaced position, for latching said safety valve open folowing a predetermined period of burning of the gas flowing through the pilot valve whereupon said axial movement may be reversed, and for opening the main valve upon continued rotation of the handle in said given direction to a third position, the improvement comprising:
3. In a gas control apparatus as set forth in claim 2, wherein said hammer means includes a two-armed lever with a hammer on one arm thereof, said lever having a slot intermediate said arms, a pin extending through said slot and pivotally supporting said lever, a spring connected to said lever and urging the hammer against the element and said lever to a position at which said pin is at one end of said slot, said actuating means having a cam to contact said other arm and actuate said lever.
4. In a gas control apparatus as set forth in claim 2,
1. In a rotary gas control having a thermoelectric safety device comprising valve means including a safety valve, rotary handle means connected to said valve means and rotatable from a gas-off position first to an ignition stand-by position and then into a gas-on position, a piezoelectric ignition device, an impact mechanism for said device means connecting the handle means and the impact mechanism for actuating the mechanism to impact on the device upon movement of the handle, the improvement comprising:
2. In a gas control apparatus comprising a housing member on which is mounted a piezoelectric ignition element, a pilot valve, a main burner valve, a safety valve between a gas inlet and the pilot and main burner valves, valve actuating means operatively connecting the valves and including a movable handle for maintaining all of said valves closed at a first rotational position, for opening the pilot valve at a second rotational position in a given rotational direction from said first position, for opening said safety valve after axial movement of the handle at said second rotational position to an axially displaced position, for latching said safety valve open folowing a predetermined period of burning of the gas flowing through the pilot valve whereupon said axial movement may be reversed, and for opening the main valve upon continued rotation of the handle in said given direction to a third position, the improvement comprising:
3. In a gas control apparatus as set forth in claim 2, wherein said hammer means includes a two-armed lever with a hammer on one arm thereof, said lever having a slot intermediate said arms, a pin extending through said slot and pivotally supporting said lever, a spring connected to said lever and urging the hammer against the element and said lever to a position at which said pin is at one end of said slot, said actuating means having a cam to contact said other arm and actuate said lever.
4. In a gas control apparatus as set forth in claim 2,
Description:
The invention relates to a rotary gas control for gas-heated apparatus having a rotary handle for rotation from a gas-off position via an ignition stand-by position into a gas-on position and in which the rotating motion of the handle enables a piezo-electric ignition device with an impact mechanism to be stressably and automatically triggered.
According to a co-pending application by Ernst Sohnchen for ROTARY VALVE AND PIEZOELECTRIC FIRING UNIT filed Oct. 28, 1971 Ser. No. 193 300 the rotary handle is moved in three positions. The ignition position is first reached from the off position by counter clockwise rotation. Ignition gas is released immediately before reaching the ignition position and the piezo impact mechanism is energized. Upon reaching the ignition position, flow of the ignition gas is maintained and the impact mechanism is triggered. This actuating motion may be repeated as often as is desired should it become necessary. Further rotation of the rotary handle, the flow of ignition gas being maintained, also releases the flow of gas for the main burner. To shut down, the rotary handle is returned into the starting position. In these conditions, a nose, provided on the rotary handle, moves below the control arm of the impact element so that the control arm once again assumes its stand-by position an the rotary gas switch. This kind of rotary gas control may be used, for example, in conjunction with a known bimetallic ignition safety device for monitoring the main gas path.
It is known that there must be provision for placing the armature plate of the switch magnet manually in position in a thermoelectric ignition safety device. Such positioning is maintained until the thermocouple is sufficiently heated by the ignition flame to energize the retaining magnet.
The object of the present invention is to ignite the pilot flame piezo-electrically when the rotary handle is rotated into the ignition position and to cause the armature plate to bear on the magnet. Furthermore, it is another object of the invention to permit, from the beginning of the time at which the ignition gas path is opened to the time at which the piezo igniter is triggered, a flushing time during which the air contained in the pilot gas pipe may escape so that the pilot flame is reliably ignited when the stressed impact element is triggered.
According to the invention this problem is solved in that the rotary handle can be depressed only in the ignition stand-by position when the impact mechanism is stressed in order to push open a safety valve of a thermoelectric ignition safety device and to release an ignition gas flow and may be further rotatable in the depressed position to a limited extent sufficient for triggering the ignition device.
The rotation of the rotary handle into the ignition stand-by position terminates at a ratchet position at which the ignition gas valve is open but at which the ignition gas is not yet flowing and the piezo impact mechanism is stressed. Depressing the rotary handle in this rotary position causes the armature plate to bear against the retaining magnet and the ignition gas to be released, namely in known manner by opening of the safety valve preceding the previously opened ignition gas valve (see valve 78 in FIG. 5 of the co-pending application by Gunther Mobus and Ernst Sohnchen for GAS CONTROL SYSTEM WITH THERMOELECTRIC IGNITION SAFETY DEVICE filed Apr. 29, 1971 Serial No 138 579 and assigned to Joh. Vaillant KG.). Furthermore, the rotary handle may be rotated through a slotted link guide to the left as far as a fixed stop abutment and the piezo impact mechanism may be triggered so that the ignition flame is ignited.
When the magnet is sufficiently energized, that is to say the safety valve remains open, the rotary handle is turned back to the right into a set position whereupon a spring then returns the handle in the axail direction. In this position of the rotary handle the thermoelectric safety device is open and the pilot flame burns. Further rotation of the rotary handle into the next set position opens the main gas valve while the pilot flame continues to burn.
In the previously mentioned operating sequence, the depressing action and triggering of the piezo ignition device is separated by a rotary motion which provides a time delay between the release of ignition gas and the ignition thereof. Accordingly, the ignition spark is not produced simultaneously with the release of the ignition gas occasioned by depressing the rotary handle. If this is the case, experience shows that the piezo-electric igniter must be repeatedly actuated, that is to say the entire operating sequence of the rotary handle may have to be repeated several times from the off position, past the position of ignition stand-by to the depressed position in order to trigger ignition. This is due to the fact that after the heater has been inoperative for a given period of time it is necessary for the ignition gas to displace the air contained in the ignition burner tube.
In the case of the embodiment according to the invention it is possible to utilize the flushing period between depressing of the rotary gas switch and triggering of the impact mechanism in order to displace the air, in particular if the user is advised in the operating instructions attached to the heater, to dwell briefly between depressing and further rotation.
One embodiment of the invention is explained hereinbelow by reference to the accompanying drawings in which:
FIG. 1 shows in diagrammatic form a rotary gas control according to the invention in the closed position.
FIG. 2 shows the rotary gas control in the ignition stand-by position.
FIG. 3 shows a detail of FIG. 2 in plan view.
FIG. 4 shows the rotary gas control in the depressed position.
FIG. 5 shows a detail similar to FIG. 3 further rotation of the rotary handle for triggering the ignition.
FIG. 6 shows the rotary gas control in the open position.
FIG. 7 shows a front view of the rotary gas control with the piezo-electric ignition device in the closed position.
FIG. 8 is a view corresponding to FIG. 7 in the ignition stand-by position.
FIG. 9 is a view corresponding to FIG. 7 in the ignition position.
FIG. 10 is a view corresponding to FIG. 7 in the operating position.
FIG. 11 is a sectional view of an entire rotary gas control with thermoelectric ignition safety device.
In FIG. 1 a collar 3 of a rotary handle 2 is rotatably supported in a housing 1. A tubular extension 5 is unitary with the collar 3. On the circumference of part of the length of the extension there is a cam 6. The valve closure 7 is moved from its seat by a valve stem 8 actuated by cam 6 against the urging of a spring 9. This permits gas to flow from an ignition gas duct 10 through a passage 11 to the ignition burner duct 12. Cams 13 are mounted on the circumference of the rotary handle within the tubular extension 5. Opposite these cams is a thrust member 14 having cam tracks 16. A spring (not shown in this view) urges a thrust pin 15 upwardly in FIG. 1 so that cam tracks 16 are resiliently urged against cam 13. In the position illustrated in FIG. 1 the cams are positioned in the depressions 17. This position is the off position of the gas control, that is to say both the ignition gas passage and the main gas passage are closed.
To put the heater into operation the rotary handle 2 is rotated to the FIG. 2 position. The cams 13 move from the depressions 17 to the depressions 18. In the present embodiment the position of the thrust member 14 has not changed axially relative to the off position. However, the cam 6 has moved the valve closure 7 from its seat thus opening the passage from the ignition gas duct 10 to the ignition burner duct 12. This rotation into the ignition stand-by position causes the slots 19, distributed about the circumference of the collar 3, to be aligned with noses 20, which are fixed relative to the housing, a feature shown in FIG. 3 in plan view and diagrammatically in the interests of clarity.
If the rotary handle 2 is depressed from the FIG. 2 position, the position shown in FIG. 4 will be obtained. Depressing the handle causes the position of the valve closure 7 to remain unchanged. The thrust member 14 and the thrust pin 15 causes an magnet armature plate to be placed against a safety magnet and a safety valve closure, raised from its seat, allows gas to pass by the valve closure 7 and through the ignition burner duct 12 to the ignition burner, a feature which is not separately illustrated. In equally known manner, a main gas valve, controlling the passage to the burner, and being disposed upstream and opposite the safety valve, continues to remain closed when the armature plate is placed in the appropriate position and the safety valve is open.
When the rotary handle 2 is turned from the FIG. 1 position into the ignition stand-by position illustrated in FIG. 2, this also moves a cam 21 against the end 22 of an impact element 23. The motion moves the impact element 23 from the FIG. 7 position to the FIG. 8 position against the urging of spring 24. This is accomplished simultaneously with the movement of valve closure 7 away from its seat as previously discussed.
The impact element 23 is pivotally mounted on a bearing pin 26 which is joined to a frame 25. The frame 25, fixedly joined to the housing 1, also supports a piezo element 27 against abutment 28.
Indicating marks are provided on the rotary handle. These may be brought into alignment with the pointer 29 which is fixed relative to the housing. The off position of the gas switch is a solid black dot 30, the ignition stand-by position has as a symbol the star 31, the ignition position, obtained by additional rotation of the rotary handle 2, is identified by a star and a jagged arrow 32 and, if the mark 33 coincides with the pointer 29 the gas switch shall have reached the full burning position.
In the previously described ignition stand-by position of the rotary handle and in the depressed state thereof, the rotary handle 2 continues to be moved from the rotary position illustrated in FIG. 4 by the rotary distance a, the apertures 19 on the collar 3 of the rotary handle 2 move below the noses 20 as far as the stop abutments 34 which extend from the noses, see FIG. 5. The depression of the rotary handle opens the safety valve so that gas commences to flow to the ignition burner. The time which elapses from that occurrence and left-hand rotation to the previously mentioned stop abutment 34 is the flushing time during which the air in the ignition burner tube 12 may escape. As the rotary handle 2 is moved the distance a (That is, until the radial edge of collar 3 at slot 19 meets the stop abutments 34 or until the mark 32 coincides with the mark 29) the cam 21 moves past the control arm 22 of the impact element 23 so that the hammer 35 thereof strikes the impact bolt 36 of the piezo element due to the force exerted by the spring 24, thus producing an ignition spark which ignites the ignition burner. The full line depiction of the impact element 23 in FIG. 9 illustrates its position at the start of this rotary motion and the dashed line depiction shows its position at the completion of this movement.
After the retaining magnet is energized in known manner by the heating of the thermocouple, a rotary handle 2 is allowed to rotate in the reverse direction by the rotary distance a. This occurs by reason of the cam 13 sliding down the incline 37 of cam track 16. The thrust member 14 follows axially and once again assumes the starting position according to FIG. 4. After the rotary handle is released, it once again moves outwardly so that the thrust member 14 once again assumes its position illustrated in FIG. 2.
In order to open the main gas passage to the burner, the rotary handle 2 is rotated from the position according to 2 into the position according to FIGS. 6 and FIG. 10. Under these conditions the thrust member 14 follows the cam 13 so that the cams 13 are seated in the depressions 38.
This axial motion of the thrust member 14 and of the thrust pin 15 opens the main burner gas valve, previously kept closed, said valve controlling the passage of gas to the burner and being disposed downstream of the safety valve. The main gas valve is handle only in the open position illustrated in FIG. 6. As is known, the gas path as described is controlled by the gas valve of the low-water safety device.
To shut down the heater the rotary handle is turned back to the right (clockwise as viewed from the end of the handle) into its off position illustrated in FIG. 1. The cam 21 moves below the control arm 22 of the impact element 23 which is deflected because of the slot 39.
FIG. 11 shows the entire construction of the rotary gas switch thermoelectric ignition safety device, corresponding substantially to the said co-pending application by Gunther Mobus and Ernst Sohnchen entitled "Gas Control System with Thermoelectric Ignition Safety Device" filed Apr. 29, 1971 Ser. No. 138 579 (see FIGS. 5-8 thereof) to which reference is had for supplementing the disclosure.
The thrust pin 15 acts via a rocker lever 38 on to a push rod 39. The rod moves in sealing-tight manner through a main valve closure 40 which controls the gas path leading to a gas outlet 41 which in turn connects to the main burner. A spring 50 bears against a collar 51 on push rod 39 and against a wall of the housing 1 to urge rod 39 downwardly in FIG. 11. In turn a collar 52 on rod 39 urges rocker lever 38 in a clockwise direction and thrust pin 15 and handle 2 to the left. The rod 39 enables a safety valve closure 42 to be pushed open to permit gas from the inlet 43 to reach the passage 12 (the movement taking place against the gas stream) pushed open to permit gas. The closure 42 also embodies the armature for the ignition safety magnet 44. Reverse motion of the push rod 39 to the open position of the rotary handle 2 causes a stop abutment 45 to entrain the valve closure 40 thus opening the gas path to the main burner.
According to a co-pending application by Ernst Sohnchen for ROTARY VALVE AND PIEZOELECTRIC FIRING UNIT filed Oct. 28, 1971 Ser. No. 193 300 the rotary handle is moved in three positions. The ignition position is first reached from the off position by counter clockwise rotation. Ignition gas is released immediately before reaching the ignition position and the piezo impact mechanism is energized. Upon reaching the ignition position, flow of the ignition gas is maintained and the impact mechanism is triggered. This actuating motion may be repeated as often as is desired should it become necessary. Further rotation of the rotary handle, the flow of ignition gas being maintained, also releases the flow of gas for the main burner. To shut down, the rotary handle is returned into the starting position. In these conditions, a nose, provided on the rotary handle, moves below the control arm of the impact element so that the control arm once again assumes its stand-by position an the rotary gas switch. This kind of rotary gas control may be used, for example, in conjunction with a known bimetallic ignition safety device for monitoring the main gas path.
It is known that there must be provision for placing the armature plate of the switch magnet manually in position in a thermoelectric ignition safety device. Such positioning is maintained until the thermocouple is sufficiently heated by the ignition flame to energize the retaining magnet.
The object of the present invention is to ignite the pilot flame piezo-electrically when the rotary handle is rotated into the ignition position and to cause the armature plate to bear on the magnet. Furthermore, it is another object of the invention to permit, from the beginning of the time at which the ignition gas path is opened to the time at which the piezo igniter is triggered, a flushing time during which the air contained in the pilot gas pipe may escape so that the pilot flame is reliably ignited when the stressed impact element is triggered.
According to the invention this problem is solved in that the rotary handle can be depressed only in the ignition stand-by position when the impact mechanism is stressed in order to push open a safety valve of a thermoelectric ignition safety device and to release an ignition gas flow and may be further rotatable in the depressed position to a limited extent sufficient for triggering the ignition device.
The rotation of the rotary handle into the ignition stand-by position terminates at a ratchet position at which the ignition gas valve is open but at which the ignition gas is not yet flowing and the piezo impact mechanism is stressed. Depressing the rotary handle in this rotary position causes the armature plate to bear against the retaining magnet and the ignition gas to be released, namely in known manner by opening of the safety valve preceding the previously opened ignition gas valve (see valve 78 in FIG. 5 of the co-pending application by Gunther Mobus and Ernst Sohnchen for GAS CONTROL SYSTEM WITH THERMOELECTRIC IGNITION SAFETY DEVICE filed Apr. 29, 1971 Serial No 138 579 and assigned to Joh. Vaillant KG.). Furthermore, the rotary handle may be rotated through a slotted link guide to the left as far as a fixed stop abutment and the piezo impact mechanism may be triggered so that the ignition flame is ignited.
When the magnet is sufficiently energized, that is to say the safety valve remains open, the rotary handle is turned back to the right into a set position whereupon a spring then returns the handle in the axail direction. In this position of the rotary handle the thermoelectric safety device is open and the pilot flame burns. Further rotation of the rotary handle into the next set position opens the main gas valve while the pilot flame continues to burn.
In the previously mentioned operating sequence, the depressing action and triggering of the piezo ignition device is separated by a rotary motion which provides a time delay between the release of ignition gas and the ignition thereof. Accordingly, the ignition spark is not produced simultaneously with the release of the ignition gas occasioned by depressing the rotary handle. If this is the case, experience shows that the piezo-electric igniter must be repeatedly actuated, that is to say the entire operating sequence of the rotary handle may have to be repeated several times from the off position, past the position of ignition stand-by to the depressed position in order to trigger ignition. This is due to the fact that after the heater has been inoperative for a given period of time it is necessary for the ignition gas to displace the air contained in the ignition burner tube.
In the case of the embodiment according to the invention it is possible to utilize the flushing period between depressing of the rotary gas switch and triggering of the impact mechanism in order to displace the air, in particular if the user is advised in the operating instructions attached to the heater, to dwell briefly between depressing and further rotation.
One embodiment of the invention is explained hereinbelow by reference to the accompanying drawings in which:
FIG. 1 shows in diagrammatic form a rotary gas control according to the invention in the closed position.
FIG. 2 shows the rotary gas control in the ignition stand-by position.
FIG. 3 shows a detail of FIG. 2 in plan view.
FIG. 4 shows the rotary gas control in the depressed position.
FIG. 5 shows a detail similar to FIG. 3 further rotation of the rotary handle for triggering the ignition.
FIG. 6 shows the rotary gas control in the open position.
FIG. 7 shows a front view of the rotary gas control with the piezo-electric ignition device in the closed position.
FIG. 8 is a view corresponding to FIG. 7 in the ignition stand-by position.
FIG. 9 is a view corresponding to FIG. 7 in the ignition position.
FIG. 10 is a view corresponding to FIG. 7 in the operating position.
FIG. 11 is a sectional view of an entire rotary gas control with thermoelectric ignition safety device.
In FIG. 1 a collar 3 of a rotary handle 2 is rotatably supported in a housing 1. A tubular extension 5 is unitary with the collar 3. On the circumference of part of the length of the extension there is a cam 6. The valve closure 7 is moved from its seat by a valve stem 8 actuated by cam 6 against the urging of a spring 9. This permits gas to flow from an ignition gas duct 10 through a passage 11 to the ignition burner duct 12. Cams 13 are mounted on the circumference of the rotary handle within the tubular extension 5. Opposite these cams is a thrust member 14 having cam tracks 16. A spring (not shown in this view) urges a thrust pin 15 upwardly in FIG. 1 so that cam tracks 16 are resiliently urged against cam 13. In the position illustrated in FIG. 1 the cams are positioned in the depressions 17. This position is the off position of the gas control, that is to say both the ignition gas passage and the main gas passage are closed.
To put the heater into operation the rotary handle 2 is rotated to the FIG. 2 position. The cams 13 move from the depressions 17 to the depressions 18. In the present embodiment the position of the thrust member 14 has not changed axially relative to the off position. However, the cam 6 has moved the valve closure 7 from its seat thus opening the passage from the ignition gas duct 10 to the ignition burner duct 12. This rotation into the ignition stand-by position causes the slots 19, distributed about the circumference of the collar 3, to be aligned with noses 20, which are fixed relative to the housing, a feature shown in FIG. 3 in plan view and diagrammatically in the interests of clarity.
If the rotary handle 2 is depressed from the FIG. 2 position, the position shown in FIG. 4 will be obtained. Depressing the handle causes the position of the valve closure 7 to remain unchanged. The thrust member 14 and the thrust pin 15 causes an magnet armature plate to be placed against a safety magnet and a safety valve closure, raised from its seat, allows gas to pass by the valve closure 7 and through the ignition burner duct 12 to the ignition burner, a feature which is not separately illustrated. In equally known manner, a main gas valve, controlling the passage to the burner, and being disposed upstream and opposite the safety valve, continues to remain closed when the armature plate is placed in the appropriate position and the safety valve is open.
When the rotary handle 2 is turned from the FIG. 1 position into the ignition stand-by position illustrated in FIG. 2, this also moves a cam 21 against the end 22 of an impact element 23. The motion moves the impact element 23 from the FIG. 7 position to the FIG. 8 position against the urging of spring 24. This is accomplished simultaneously with the movement of valve closure 7 away from its seat as previously discussed.
The impact element 23 is pivotally mounted on a bearing pin 26 which is joined to a frame 25. The frame 25, fixedly joined to the housing 1, also supports a piezo element 27 against abutment 28.
Indicating marks are provided on the rotary handle. These may be brought into alignment with the pointer 29 which is fixed relative to the housing. The off position of the gas switch is a solid black dot 30, the ignition stand-by position has as a symbol the star 31, the ignition position, obtained by additional rotation of the rotary handle 2, is identified by a star and a jagged arrow 32 and, if the mark 33 coincides with the pointer 29 the gas switch shall have reached the full burning position.
In the previously described ignition stand-by position of the rotary handle and in the depressed state thereof, the rotary handle 2 continues to be moved from the rotary position illustrated in FIG. 4 by the rotary distance a, the apertures 19 on the collar 3 of the rotary handle 2 move below the noses 20 as far as the stop abutments 34 which extend from the noses, see FIG. 5. The depression of the rotary handle opens the safety valve so that gas commences to flow to the ignition burner. The time which elapses from that occurrence and left-hand rotation to the previously mentioned stop abutment 34 is the flushing time during which the air in the ignition burner tube 12 may escape. As the rotary handle 2 is moved the distance a (That is, until the radial edge of collar 3 at slot 19 meets the stop abutments 34 or until the mark 32 coincides with the mark 29) the cam 21 moves past the control arm 22 of the impact element 23 so that the hammer 35 thereof strikes the impact bolt 36 of the piezo element due to the force exerted by the spring 24, thus producing an ignition spark which ignites the ignition burner. The full line depiction of the impact element 23 in FIG. 9 illustrates its position at the start of this rotary motion and the dashed line depiction shows its position at the completion of this movement.
After the retaining magnet is energized in known manner by the heating of the thermocouple, a rotary handle 2 is allowed to rotate in the reverse direction by the rotary distance a. This occurs by reason of the cam 13 sliding down the incline 37 of cam track 16. The thrust member 14 follows axially and once again assumes the starting position according to FIG. 4. After the rotary handle is released, it once again moves outwardly so that the thrust member 14 once again assumes its position illustrated in FIG. 2.
In order to open the main gas passage to the burner, the rotary handle 2 is rotated from the position according to 2 into the position according to FIGS. 6 and FIG. 10. Under these conditions the thrust member 14 follows the cam 13 so that the cams 13 are seated in the depressions 38.
This axial motion of the thrust member 14 and of the thrust pin 15 opens the main burner gas valve, previously kept closed, said valve controlling the passage of gas to the burner and being disposed downstream of the safety valve. The main gas valve is handle only in the open position illustrated in FIG. 6. As is known, the gas path as described is controlled by the gas valve of the low-water safety device.
To shut down the heater the rotary handle is turned back to the right (clockwise as viewed from the end of the handle) into its off position illustrated in FIG. 1. The cam 21 moves below the control arm 22 of the impact element 23 which is deflected because of the slot 39.
FIG. 11 shows the entire construction of the rotary gas switch thermoelectric ignition safety device, corresponding substantially to the said co-pending application by Gunther Mobus and Ernst Sohnchen entitled "Gas Control System with Thermoelectric Ignition Safety Device" filed Apr. 29, 1971 Ser. No. 138 579 (see FIGS. 5-8 thereof) to which reference is had for supplementing the disclosure.
The thrust pin 15 acts via a rocker lever 38 on to a push rod 39. The rod moves in sealing-tight manner through a main valve closure 40 which controls the gas path leading to a gas outlet 41 which in turn connects to the main burner. A spring 50 bears against a collar 51 on push rod 39 and against a wall of the housing 1 to urge rod 39 downwardly in FIG. 11. In turn a collar 52 on rod 39 urges rocker lever 38 in a clockwise direction and thrust pin 15 and handle 2 to the left. The rod 39 enables a safety valve closure 42 to be pushed open to permit gas from the inlet 43 to reach the passage 12 (the movement taking place against the gas stream) pushed open to permit gas. The closure 42 also embodies the armature for the ignition safety magnet 44. Reverse motion of the push rod 39 to the open position of the rotary handle 2 causes a stop abutment 45 to entrain the valve closure 40 thus opening the gas path to the main burner.