Patent Publication Number: US-9845954-B2

Title: Combustion control device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U. S. C. §119 to Japanese Patent Application No. 2013-231132, filed on Nov. 7, 2013, the entire content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a combustion control device, and more particularly relates to a combustion control device in which a pressure within a mixer is rapidly increased at the time of ignition of the combustion control device, the transmission of the temporarily increased pressure to a pressure sensor is reduced, the pressure sensor is brought into a non-operated state and thus the combustion of the combustion control device is continued. 
     BACKGROUND ART 
     As an example of the combustion control device, there is a combustion control device that will be disclosed below in patent document 1. 
     The combustion control device disclosed in patent document 1 is a combustion device which previously mixes a combustion gas and air to feed it into the flame hole of a burner, which includes a mixture supply passage for feeding the mixture obtained by mixing the combustion gas and the air into the flame hole of the burner, a bypass passage whose entrance portion and exit portion are open into the mixture supply passage and a mixture amount sensor that is arranged partway along the bypass passage, in which the exit portion of the bypass passage is open to a portion close to the flame hole of the burner as compared with the entrance portion on a downstream side, and the mixture amount sensor measures the quantity of flow of the mixture divided to the side of the bypass passage among the mixture flowing into the mixture supply passage. 
     The combustion control device disclosed in patent document 1 accurately controls an air-fuel ratio without being affected by clogging of the burner or the like. 
     RELATED ART DOCUMENT 
     Patent Document 
     Patent document 1: Japanese Unexamined Patent Application Publication No. H11-159745 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     Incidentally, a conventional combustion control device includes, for example, a combustion chamber, a burner (also called a “metal knit burner”), a mixer and a pressure sensor. 
     Here, the combustion chamber has a heat dissipation disc on the front side and a combustion room therewithin. 
     The burner is attached to the back surface side of the combustion chamber. 
     Furthermore, the mixer mixes a gas formed of propane, natural gas or the like with air to supply the mixture to the burner. 
     Then, in order for the pressure within the mixer, for example, the state of clogging of the exit of the burner to be checked, one end of a pressure passage is connected to the mixer, and, the other end of the pressure passage is connected to the pressure sensor. 
     At the time of ignition of the combustion control device, the pressure within the combustion chamber is instantaneously and rapidly increased by the pressure of the ignition of the gas combustion. 
     Here, since the combustion chamber of the combustion control device has a heat dissipation disc on the front side, it is difficult to remove the pressure within the combustion chamber. 
     Then, when the pressure within the combustion chamber is rapidly increased, the burner portion is instantaneously brought into the state where it is completely clogged. 
     Consequently, the pressure within the mixer is also rapidly increased by the pressure within the combustion chamber that is prevented from being moved, as shown in  FIG. 5 , this pressure acts on the pressure sensor through the pressure passage and a “peak” is produced and the pressure sensor is operated, with the result that it is disadvantageously impossible to continue the combustion in the combustion control device. 
     An object of the present invention is to realize a combustion control device that reduces, when a pressure within a mixer is rapidly increased at the time of ignition of the combustion control device, the transmission of the temporarily increased pressure to a pressure sensor, that brings the pressure sensor into a non-operated state and that thereby can continue combustion in the combustion control device. 
     Means for Solving the Problem 
     Hence, in order to remove the above inconvenience, according to the present invention, there is provided a combustion control device including: a combustion chamber which has a heat dissipation disc on a front surface and within which a combustion room is formed; a burner which is attached to the combustion chamber; a mixer which mixes a gas supplied to the burner with air; and a pressure sensor which is connected to the mixer through a pressure passage, where a pressure propagation delay means which reduces transmission to the pressure sensor caused by a temporary pressure increase within the mixer is provided partway along the pressure passage. 
     Effects of the Invention 
     In the present invention, since in the combustion control device, the pressure propagation delay means for reducing the transmission to the pressure sensor caused by the temporary pressure increase within the mixer is provided partway along the pressure passage making the mixer communicate with the pressure sensor, when the pressure within the mixer is rapidly increased at the time of ignition of the combustion control device, the pressure propagation delay means reduces the transmission of the temporarily increased pressure to the pressure sensor, and thus it is possible to bring the pressure sensor into a non-operated state. 
     In this way, since it is possible to keep the pressure sensor in the non-operated state, it is possible to continue the combustion in the combustion control device. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic configuration diagram of a combustion control device (first embodiment); 
         FIG. 2  is an enlarged cross-sectional view of the main portion of an orifice (first embodiment); 
         FIG. 3  is a diagram showing variations in the pressure of the combustion control device (first embodiment); 
         FIG. 4  is an enlarged cross-sectional view of the main portion of a pressure adjustment valve (second embodiment); and 
         FIG. 5  is a diagram showing variations in the pressure of a conventional combustion control device. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention will be described in detail below with reference to drawings. 
     First Embodiment 
       FIGS. 1 to 3  show a first embodiment of the present invention. 
     In  FIG. 1 , reference numeral  1  represents a combustion control device. 
     The combustion control device  1  includes a combustion chamber  2 , a burner  3 , a mixer  4  and a pressure sensor  5 . 
     Specifically, the combustion chamber  2  includes, as shown in  FIG. 1 , a heat dissipation disc  6  on the front side, and forms a combustion room  7  therewithin. 
     The burner  3  is also called a “metal knit burner”, and is attached to the back side of the combustion chamber  2 . 
     Furthermore, the mixer  4  mixes a gas formed of propane, natural gas or the like with air to supply the mixture to the burner  3 . Here, a nozzle  8  is connected to the mixer  4 , and a gas line is connected to the nozzle  8 . A combustion fan  9  is also connected to the mixer  4 , the combustion fan  9  is rotated by the drive of a combustion fan motor  10  and air is supplied to the mixer  4 . 
     Then, in order for the pressure within the mixer  4 , for example, the state of clogging of the exit of the burner  3  to be checked, one end of a pressure passage  11  is connected to the mixer  4 , and, the other end of the pressure passage  11  is connected to the pressure sensor  5 . 
     The combustion control device  1  includes a control means  12  that controls, for example, the combustion state. 
     As shown in  FIG. 1 , the mixer  4  is connected to the control means  12 , and thus the state of agitation of the mixer  4  is controlled. 
     The pressure sensor  5  is connected to the control means  12 , and a detection signal from the pressure sensor  5  is input. 
     Moreover, a supply amount adjustment means (not shown) arranged partway along the gas line of the nozzle  8  is also connected to the control means  12 , and the amount of gas supplied is controlled. 
     Furthermore, the combustion fan motor  10  is also connected to the control means  12 , the combustion fan motor  10  is driven and controlled to rotate the combustion fan  9  and air is supplied to the mixer  4 , with the result that the combustion state is controlled. 
     In the combustion control device  1 , partway along the pressure passage  11 , a pressure propagation delay means  13  is provided that reduces transmission to the pressure sensor  5  by a temporarily increased pressure within the mixer  4 . 
     Specifically, the pressure propagation delay means  13  is formed with an orifice. 
     In other words, in the pressure propagation delay means  13 , as shown in  FIG. 2 , a main body portion  13 - 1  arranged partway along the pressure passage  11  is formed of, for example, brass into the shape of a cylinder, and in the center of the main body portion  13 - 1 , a communication hole portion  13 - 2  penetrating in a longitudinal direction is formed. 
     Here, when the passage diameter D of the pressure passage  11  is set at, for example, 4 mm, the diameter d of the communication hole portion  13 - 2  of the pressure propagation delay means  13  is set at, for example, 1 mm in consideration of a state where the pressure is increased. 
     The length L of the main body portion  13 - 1  of the pressure propagation delay means  13  is set at, for example, 20 mm. 
     An action will be described. 
     The supply amount adjustment means is controlled by the control means  12  of the combustion control device  1  to supply the gas to the mixer  4  through the nozzle  8 , and on the other hand, the combustion fan motor  10  is driven and controlled to rotate the combustion fan  9  to supply air to the mixer  4 . 
     Then, while the agitation state of the mixer  4  is being controlled by the control means  12 , the combustion state of the burner  3  is controlled. 
     At the time of ignition of the combustion control device  1  that is, at the time of combustion control described above, the pressure within the combustion chamber  2  is rapidly increased by the pressure of the ignition of the gas combustion. 
     However, since the combustion chamber  2  of the combustion control device  1  has the heat dissipation disc  6  on the front side, and thus it is difficult to remove the pressure, the burner portion  3  is instantaneously brought into the state where it is completely clogged. 
     Then, the pressure within the mixer  4  is also rapidly increased by the pressure within the combustion chamber  2  that is prevented from being moved, this rapidly increased pressure is passed to the pressure passage  11 . 
     Here, although the rapidly increased pressure reaches the pressure propagation delay means  13  arranged partway along the pressure passage  11 , since the rapidly increased pressure is gradually passed through the communication hole portion  13 - 2  formed in the pressure propagation delay means  13 , as shown in  FIG. 3 , the communication hole portion  13 - 2  of the pressure propagation delay means  13  reduces the transmission of the rapidly increased pressure to the pressure sensor  5 , that is, a “peak cut” is performed. 
     In this way, since the pressure propagation delay means  13  for reducing the transmission to the pressure sensor  5  by the temporary pressure increase within the mixer  4  is provided partway along the pressure passage  11 , even if at the time of ignition of the combustion control device  1 , the pressure within the mixer  4  is rapidly increased, that is, the pressure is instantaneously increased, the transmission of the pressure temporarily increased to the pressure sensor  5  can be reduced by the pressure propagation delay means  13 , with the result that it is possible to bring the pressure sensor  5  into a non-operated state. 
     Hence, since it is possible to keep the pressure sensor  5  in the non-operated state, it is possible to continue the combustion of the combustion control device  1 . 
     Moreover, the pressure propagation delay means  13  is formed with the orifice, and thus it is possible to expect the effect of the pressure reduction described above, and on the other hand, since the configuration is simple and it is easy to perform its production, it is possible to reduce its cost. 
     Second Embodiment 
       FIG. 4  shows a second embodiment of the present invention. 
     In the second embodiment, parts having the same functions as in the first embodiment described above are identified with the same symbols, and a description will be given of them. 
     The second embodiment is characterized in that a pressure propagation delay means  21  provided partway along the pressure passage  11  is formed with a pressure adjustment valve that can adjust the speed at which the pressure is propagated. 
     Specifically, the pressure propagation delay means  21  formed with the pressure adjustment valve includes: a main body portion  21 - 1  that is arranged partway along the pressure passage  11  and that is cylindrical; an inner space  21 - 2  that is formed within the main body portion  21 - 1 ; a valve member  21 - 3  that is arranged within the inner space  21 - 2  and that is spherical; first and second elastic springs  21 - 4  and  21 - 5  that hold the valve member  21 - 3  from both sides. 
     Here, as shown in  FIG. 4 , in the main body portion  21 - 1 , the diameter of the inner space  21 - 2  is gradually decreased as the inner space  21 - 2  extends from the center part to both ends. 
     At both ends of the main body portion  21 - 1 , first and second opening portions  21 - 6  and  21 - 7  that communicate with the pressure passage  11  are provided. 
     The valve member  21 - 3  is retained by the first and second elastic springs  21 - 4  and  21 - 5  from both end sides such that within the inner space  21 - 2  of the main body portion  21 - 1 , a normal position is produced in the approximate center part. 
     Hence, when the pressure within the mixer is varied, the increased pressure causes the valve member  21 - 3  of the pressure propagation delay means  21  to be moved against a force applied by the elastic springs. 
     Then, the gap between the valve member  21 - 3  and the main body portion  21 - 1 , that is, the inner space  21 - 2  is varied, and thus the cross section of the pressure passage  11  is varied, with the result that the speed at which the pressure is propagated is adjusted. 
     More specifically, when the valve member  21 - 3  is in the normal position in the approximate center part of the main body portion  21 - 1 , the inner space  21 - 2 , which is the gap between the valve member  21 - 3  and the main body portion  21 - 1 , is maximized. 
     Hence, since when the valve member  21 - 3  is moved by a variation in the pressure, the inner space  21 - 2  is moved only in a direction in which the inner space  21 - 2  is reduced, the pressure rapidly increased within the mixer is reduced by the pressure propagation delay means  21  and is transmitted to the pressure sensor. 
     Consequently, since the pressure propagation delay means  21  for reducing the transmission to the pressure sensor by the temporary pressure increase within the mixer is provided partway along the pressure passage  11 , and the pressure propagation delay means  21  is formed with the pressure adjustment valve that adjusts the speed at which the pressure is propagated by varying the cross section of the pressure passage  11  according to the pressure within the mixer, even if the pressure within the mixer is rapidly increased at the time of ignition of the combustion control device, it is possible to reduce, with the pressure propagation delay means  21  formed with the pressure adjustment valve, the transmission of the temporarily increased pressure to the pressure sensor, to bring the pressure sensor into a non-operated state and to continue the combustion in the combustion control device. 
     The pressure propagation delay means  21  is formed with the pressure adjustment valve, and thus it is possible to reduce, with the first and second elastic springs  21 - 4  and  21 - 5 , the pressure transmitted to the pressure sensor to an appropriate state, with the result that it is possible to reliably acquire a non-operated state of the pressure sensor when a temporary pressure increase is produced. 
     The present invention is not limited to the first and second embodiments described above, and various modifications are possible. 
     For example, although in the first embodiment of the present invention, as the pressure propagation delay means, the venture is used, and on the other hand, in the second embodiment, as the pressure propagation delay means, the pressure adjustment valve is used, it is possible to adopt a special configuration in which both of them are used in two stages. 
     LIST OF REFERENCE SYMBOLS 
     
         
         
           
               1  combustion control device 
               2  combustion chamber 
               3  burner 
               4  mixer 
               5  pressure sensor 
               6  heat dissipation disc 
               7  combustion room 
               8  nozzle 
               9  combustion fan 
               10  combustion fan motor 
               11  pressure passage 
               12  control means 
               13  pressure propagation delay means 
               13 - 1  main body portion 
               13 - 2  communication hole portion