Abstract:
A gas burner includes a gas valve block having a gas input control part connected to a fuel gas source and a gas output control part connected to a flame tube and gas nozzle for producing an igniting flame for burning fuel gas outputted through the flame tube, a differential pressure device adapted to control the fuel gas passage between the gas input control part and the gas output control part through a normal-close valve and a normal-open valve, an electronic igniter controlled by a cock in the gas valve block through a micro-switch to discharge sparks through discharging electrode means for burning fuel gas outputted through the gas nozzle, and a temperature switch for controlling the operation of the normal-open valve and the electronic igniter subject to a predetermined temperature range.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to gas burners, and more particularly to such a gas burner, which uses a differential pressure device to control the fuel passage from a fuel gas source to the flame tube for main flame, and normal-close and normal-open valve means to control the fuel passage from the fuel gas source to the gas nozzle for igniting flame for burning fuel gas from the flame tube. 
     In countries of high degree of altitude, people usually use gas burners to keep rooms warm. Regular gas burners for this purpose commonly use a piezoelectric ignition switch (cock) to control the ignition of fuel gas and the intensity of the flame. When in use, the user must hold the piezoelectric ignition switch in the depressed position after the presence of the ignition flame, and then release the piezoelectric ignition switch after the presence of the desired main flame. In case the main flame and/or the igniting flame is extinguished by wind or an accident, the user must depress the piezoelectric ignition switch and then rotate it from the off-position to the on-position again to ignite the ignition flame so as to further ignite the main flame. 
     SUMMARY OF THE INVENTION 
     The invention has been accomplished to provide a gas burner, which eliminates the drawbacks of the conventional gas burners. It is one object of the present invention to provide a gas burner, which is easy and efficient in use. It is another object of the present invention to provide a gas burner, which prevents a fuel gas leakage when the main flame is extinguished accidentally. It is still another object of the present invention to provide a gas burner, which is automatically controlled to keep the ambient temperature within the desired range. According to one aspect of the present invention, the gas burner comprises a gas valve block having a gas input control part connected to a fuel gas source and a gas output control part connected to a flame tube and gas nozzle for producing an igniting flame for burning fuel gas outputted through the flame tube, a differential pressure device adapted to control the fuel gas passage between the gas input control part and the gas output control part through a normal-close valve and a normal-open valve, and an electronic igniter controlled by a cock in the gas valve block through a micro-switch to discharge sparks through discharging electrode means for burning fuel gas outputted through the gas nozzle. According to another aspect of the present invention, a temperature switch is electrically connected between the normal-open valve and the electronic igniter, and adapted to automatically control the operation of the normal-open valve and the electronic igniter subject to a predetermined temperature range. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a gas valve block for a gas burner according to the present invention. 
     FIG. 2 is a left side view of the gas valve block shown in FIG. 1, showing the arrangement of the internal fuel gas passage. 
     FIG. 3 is a sectional view of the gas valve block shown in FIG. 1, showing the internal structure of the gas output control part. 
     FIG. 4 illustrates the arrangement of the whole system of the gas burner according to the present invention. 
     FIG. 5 is a sectional view in an enlarged scale of a part of FIG. 4, showing the arrangement of the differential pressure device and the gas valve block. 
     FIG. 6 is a sectional view in an enlarged scale of a part of FIG. 5, showing the internal structure of the differential pressure device. 
     FIG. 7 is a front view of a part of the present invention, showing the cock and the micro-switch installed in the gas valve block. 
     FIG. 8 is a left side view of FIG.  7 . 
     FIG. 9 is similar to FIG. 5 but showing the valve stem of the differential pressure device opened from the communication hole of the gas valve block. 
     FIG. 10 illustrates the relationship between the cock and the gas input control part of the gas valve block according to the present invention. 
     FIG. 11 illustrates a gas filter element installed in the gas input control part of the gas valve block according to the present invention. 
     FIG. 12 illustrates an alternate form of the gas burner according to the present invention. 
     FIG. 13 illustrates an alternate form of the gas valve block according to the present invention. 
     FIG. 14 illustrates an alternate form of the differential pressure device according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. from  1  through  3 , a gas valve block  10  is shown comprising a gas input control part  13 , and a gas output control part  14  having a mounting end  16 . The gas input control part  13  comprises a gas inlet  11 , and an axle hole  12  in communication with the gas inlet  11 . The gas output control part  14  comprises a gas passage  15  in communication with the axle hole  12  of the gas input control part  13 . The gas passage  15  comprises a gas input hole  17 , a gas output hole  19 , and a communication hole  18  connected between the gas input hole  17  and the gas output hole  19 . 
     Referring to FIGS. 4 and 5, a gas burner  90  is shown comprising a gas valve block  10  (same as the aforesaid gas valve block), a cock  20  coupled to the gas valve block  10 , a differential pressure device  35  coupled to the gas valve block  10 , the differential pressure device  35  comprising a normal-close valve  40  and a normal-open valve  50 , a micro-switch  29  driven by the cock  20 , an electronic igniter  60 , a battery  63 , a gas nozzle  64 , a spark discharging electrode  65 , an induction electrode  66 , and a flame tube  67  having flame holes  68 . The normal-close valve  40  has a gas outlet  45  connected to the gas nozzle  64  by a gas pipe. The gas output hole  19  of the gas output control part  14  of the gas valve block  10  is connected to the flame tube  67  by a gas pipe. The electronic igniter  60  is electrically connected to the positive and negative terminals  33  and  34  of the micro-switch  29 , and also electrically connected to the terminal  43  of the normal-close valve  40  and the terminal  53  of the normal-open valve  50 . A temperature switch  61  is installed in the circuit between the electronic igniter  60  and the normal-open valve  50 . The spark discharging electrode  65  and the induction electrode  66  are respectively connected to the electronic igniter  60 . The battery  63  is connected to the electronic igniter  60  to provide the necessary working voltage. 
     Referring to FIG.  6  and FIG. 5 again, the differential pressure device  35  comprises a right shell  36 , the right shell  36  comprising a mounting portion  38  adapted for coupling to the mounting end  16  of the gas valve block  10  and a through hole  82  through the mounting portion  38 , a left shell  37 , a rubber diaphragm  87  retained between the right shell  36  and the left shell  37  and dividing the differential pressure device  35  a right gas chamber  83  and a left gas chamber  84 , a gas passage  85  communicating between the right gas chamber  83  and the left gas chamber  84 , a diaphragm rod  80 , the diaphragm rod  80  having one end perpendicularly connected to the center of one side of the rubber diaphragm  87  and an opposite end extended out of the through hole  82  of the mounting portion  38  into the inside of the gas valve block  10  and terminating in a valve stem  39  and a valve washer  89  on the valve stem  39 , a compression spring  81  mounted on the valve rod  80  and stopped between the valve stem  39  and the mounting portion  38  of the right shell  36  outside the through hole  82 . The compression spring  81  imparts a pressure to the valve stem  39 , causing the valve stem  39  and the valve washer  89  to close the communication hole  18 . The aforesaid normal-close valve  40  and normal-open valve  50  are bilaterally installed in the left shell  37 . The normal-close valve  40  comprises a valve port  41  disposed in communication between the gas outlet  45  thereof and the left gas chamber  84 , a winding  44  connected to the terminal  43  thereof, and a valve flap  42  adapted to close the valve port  41  when the winding  44  is energized, or to open the valve port  41  when the winding  44  is disenergized. The normal-open valve  50  comprises a winding  54  connected to the terminal  53  thereof, a gas hole  86  in communication between the gas passage  85  and the left gas chamber  84 , a valve port  51  in communication between the gas passage  85  and gas hole  86 , and a valve flap  52  adapted to close the valve port  51  when the winding  54  is energized, or to open the valve port  51  when the winding  54  is disenergized. 
     Referring to FIGS. 7,  8  and  10 , the cock  20  comprises a cock body  22  inserted into the axle hole  12  of the gas input control part  13  of the gas valve block  10 , a gas inlet  23  disposed at one lateral side of the cock body  22  and connected to the gas inlet  11  of the gas input control part  13  of the gas valve block  10 , a gas outlet  24  disposed at the bottom side of the cock body  22  in communication with the gas inlet  23  and connected to the gas passage  15  of the gas output control part  14  of the gas valve block  10 , and a shank  21  extended from the top side of the cock body  22  and fixedly mounted with a knob  26  and a control wheel  27 . The control wheel  27  has a peripheral notch  28 , which receives a roller  30  at the distal end of an actuating rod  31  of the micro-switch  29 . The actuating rod  31  is adapted to activate a contact  32 , so as to close/open the circuit between the positive and negative terminals  33  and  34  of the micro-switch  29 . 
     Referring to FIG.  9  and FIGS. 4 and 6 again, when operating the knob  26  to rotate the cock  20  in one direction, the roller  30  is driven by the notch  28  of the control wheel  27  to force the actuating rod  31  in activating the contact  32 , thereby causing the terminals  33  and  34  of the micro-switch  29  to be electrically connected, and therefore the electronic igniter  60  is driven to discharge sparks through the discharging electrode  65  and to give a signal to the normal-close valve  40 , causing the valve flap  42  to be driven by the winding  44  to open the valve port  41 . At the same time, the gas inlet  23  and gas outlet  24  of the cock  20  are respectively disposed in communication with the gas inlet  11  of the gas input control part  13  of the gas valve block  10  and the gas passage  15  of the gas output control part  14  of the gas valve block  10 , enabling fuel gas to pass through the through hole  82 , the right gas chamber  83 , the gas passage  85 , the gas hole  86  and the valve port  51  into the left gas chamber  84 , and then to pass from the left gas chamber  84  through the valve port  41  and the gas outlet  45  to the gas nozzle  64  and then to be burned by sparks discharged through the discharging electrode  65 . Because the valve port  41  of the normal-close valve  40  is opened, an igniting flame goes out of the gas nozzle  64 . Upon the presence of the igniting flame, the induction electrode  66  is induced to give a signal to the electronic igniter  60 , causing the electronic igniter  60  to stop discharging sparks through the discharging electrode  65 , and to send a signal to the normal-open valve  50 . Upon receive of the signal from the electronic igniter  60 , the normal-open valve  50  is driven to close the valve port  51 , preventing fuel gas to pass from the right gas chamber  83  to the left gas chamber  84 , and enabling fuel gas to be completely guided out of the left gas chamber  84  to the gas nozzle  64 . When the fuel gas in the left gas chamber  84  is gradually reduced, the air pressure in the right gas chamber  83  becomes higher than the left gas chamber  84 , thereby causing the rubber diaphragm  87  to be forced by air pressure displace in direction from the right gas chamber  83  toward the left gas chamber  84 , and at the same time the diaphragm rod  80  is moved with the rubber diaphragm  87  leftwards, causing the valve stem  39  to compress the compression spring  81 , and to open the gas input hole  17 , for enabling fuel gas to pass from the gas input hole  17  through the communication hole  18  and the gas output hole  19  to the flame holes  68  of the flame tube  67  for burning by the flame at the gas nozzle  64 , and therefore a main flame is produced at the flame tube  67 . 
     In case the igniting flame and the main flame are extinguished by an accident, the induction electrode  66  receives no flame, and the electronic igniter  60  is stopped from sending the signal to the normal-open valve  50 , thereby causing the winding  54  of the normal-open valve  50  to open the valve flap  52  from the valve port  51 , enabling fuel gas to pass from the right gas chamber  83  to the left gas chamber  84  again. When fuel gas passes from the right gas chamber  83  to the left gas chamber  84 , the air pressure in the left gas chamber  84  is gradually increased and becomes in balance with the right gas chamber  83  soon. When the air pressure in the left gas chamber  84  is in balance with the right gas chamber  83 , the rubber diaphragm  87  is returned to its former position, thereby causing the valve stem  39  to close the communication hole  18  again, preventing a leakage of fuel gas. At this time, the valve flap  42  of the normal-close valve  40  is still opened from the valve port  41 , enabling the electronic igniter  60  to drive the discharging electrode  65  to discharge sparks. If the trouble, which caused the aforesaid accident to happen, still exists at this time, the electronic igniter  60  immediately cuts off the signal from the normal-close valve  40 , causing the winding  44  of the normal-close valve  40  to be disenergized, and therefore the valve flap  42  is forced to close the valve port  41 . 
     The aforesaid temperature switch  61  is turned to a broken circuit status when its temperature surpasses a set level, causing the winding  54  of the normal-open valve  50  to be disenergized, so as to extinguish the main flame. At this time the igniting flame still exists. When the main flame is extinguished, and the temperature of the temperature switch  61  drops below the set level, the temperature switch  61  is turned from the broken circuit status to a close circuit status, causing the winding  54  of the normal-open valve  50  to be energized, and therefore the ignition flame is produced again to burn fuel gas at the flame holes  68  of the flame tube  67 . Further, a flame adjustment lever  72  is installed and adapted to adjust the intensity of the main flame. 
     Referring to FIGS. 11 and 14 and FIG. 5 again, gas filter elements  70  may be installed in the gas inlet  11  and in the fuel gas passage in front of the differential pressure device  35  to remove solid matter from fuel gas. 
     FIG. 12 shows an alternate form of the present invention. According to this alternate form, a manual switch  71  is installed in the gas burner  90  and connected to the electronic igniter  60  instead of the aforesaid micro-switch  29  and control wheel  27 . When the manual switch  71  is in the “off” position, the user needs not to turn the knob  26  to the closed position, and the user can directly switch on the manual switch  71  to turn on the electronic igniter  60 . 
     FIG. 13 shows an alternate form of the gas valve block  10 . In the aforesaid embodiments, the gas output control part  14  is formed integral with the gas input control part  13 . According to this alternate form, the gas output control part  14  and the gas input control part  13  are two separated members detachably coupled together. When the gas output control part  14  and the gas input control part  13  are coupled together, rubber seal means must be installed to seal the connection area between the gas output control part  14  and the gas input control part  13 . 
     FIG. 14 shows an alternate form of the pressure differential device  35 . According to this alternate form, a valve  47  is installed in one side of the rubber diaphragm  87  to control the passage of the communication hole  18 , a disk  48  is installed in the other side of the rubber diaphragm  87 , and a spring  49  is connected between the disk  48  and the left shell  37 . When the valve  47  is forced by the spring  49  to close the communication hole  18  when the air pressure at one side of the rubber diaphragm  87  is maintained in balance with the air pressure at the other side of the rubber diaphragm  87 . According to this embodiment, the gas output control part  14  and the gas input control part  13  can be made integral with each other, or separately made and then coupled together. 
     It is to be understood that the drawings are designed for purposes of illustration only, and are not intended for use as a definition of the limits and scope of the invention disclosed.