Patent Publication Number: US-10317086-B2

Title: Burner for a gas-heated cooking appliance

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates a burner for a gas-heated cooking appliance. 
     A burner for a gas-heated cooking appliance is known for example from WO 2006/077058 A1. The burner comprises a pipe for mixing burnable gas with primary air. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the present invention is to provide an improved burner for a gas-heated cooking appliance, which in particular is distinguished by high efficiency. 
     To achieve this object a burner is proposed for a gas-heated cooking appliance with a pipe for mixing burnable gas with primary air and a deflecting element. The deflecting element is arranged in the interior space bounded by the pipe. 
     Thanks to the deflecting element the burnable gas is mixed even better with the primary air. As a result, the burnable gas combusts even better at flame outlets of the burner, so that the energy efficiency of the burner is increased. “Deflecting element” here means an element which is designed to deflect the burnable gas, the primary air or both. The deflection here takes place in particular in respect of the main inflow direction of the burnable gas, of the primary air or of the mixture thereof. The main inflow direction may correspond to the longitudinal direction of the pipe. “Longitudinal direction” of the pipe means the direction of the pipe in which it has an essentially constant cross-section. 
     According to one embodiment one end of the pipe points to a nozzle and the other end points to a cover. The deflecting element can be arranged between and including a center of the pipe in respect of a longitudinal direction thereof and the one end. Experiment has shown that such an arrangement of the deflecting element surprisingly results in particularly large increases in the energy efficiency of the burner. “Including a center” means that the deflecting element can also be arranged precisely in the center. 
     According to another embodiment the deflecting element is cruciform in design. It has been found that with a cruciform element particularly large increases in the energy efficiency of the burner are possible. 
     According to another embodiment the deflecting element has at least one piece of wire. Such a deflecting element is simple to manufacture. 
     According to another embodiment the piece of wire has a diameter of between 0 and 3 mm, preferably between 1 and 2 mm and further preferably between 1.3 and 1.7 mm. Specifically, particularly large increases in the energy efficiency of the burner can be achieved for the values between 1.3 and 1.7 mm. 
     According to another embodiment the piece of wire is made of metal or plastic. The piece of wire can be formed integrally with the pipe. “Integrally” means that the pipe and the piece of wire are made of one and the same material and are formed in one piece. On the other hand the piece of wire may also be attached in the pipe by form fit, by force fit or by bonding. 
     According to another embodiment the pipe has an inner wall, to which the piece of wire is connected at its respective ends. This means the piece of wire can easily be attached in the pipe. 
     According to another embodiment the inner wall has a diameter of between 5 and 20 mm, preferably between 8 and 14 mm and further preferably between 10 and 12 mm. Surprisingly, it was possible to achieve particularly large increases in energy efficiency for a diameter of the inner wall between 10 and 12 mm in conjunction with a piece of wire with a diameter of between 1.3 and 1.7 mm. 
     According to another embodiment the deflecting element has two pieces of wire, which are each connected to one another in the center. This means the aforementioned cruciform shape can easily be manufactured. The two pieces of wire can be formed integrally with one another. Furthermore the two pieces of wire can be connected to one another for example by form fit. More than two pieces of wire can also be provided. 
     According to another embodiment the nozzle is arranged at a distance from the one end of the pipe. This means primary air can be sucked into the burnable gas flow exiting from the nozzle and into the one end of the pipe. 
     According to another embodiment the other end of the pipe opens out into a space underneath the cover, which is radially connected via flame outlets to the surrounding area. When the burner is installed in the gas-heated cooking appliance the pipe extends in a vertical direction. Underneath the cover the gas mixture exiting from the pipe into the space is deflected in a horizontal direction. 
     According to another embodiment the nozzle is a component of a lower part. The pipe can be a component of an upper part. Together the lower part and the upper part form a base. The cover can be placed on the upper part. The cover can define flame outlets with the upper part. 
     According to another embodiment the lower part has a chamber open on one side, into which the pipe extends. The chamber is in turn connected to openings to feed the primary air out of the surrounding area into the chamber. 
     According to another embodiment the space is formed underneath the cover between the upper part and the cover. 
     Furthermore a gas-heated cooking appliance, in particular a gas hob, is proposed with the inventive burner. 
     The burner is designed for use in the home. This means the gas-heated cooking appliance is designed as a household appliance. 
     Other possible implementations of the invention also comprise not explicitly cited combinations of features or embodiments of the burner or of the cooking appliance described previously or below in respect of the exemplary embodiments. In this case the person skilled in the art will also add or modify individual aspects as improvements or additions to the respective basic form of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantageous configurations and aspects of the invention are the subject matter of the subclaims and of the exemplary embodiments of the invention described in the following. The invention is explained in greater detail below on the basis of preferred embodiments with reference to the appended figures, in which: 
         FIG. 1 : shows a perspective view of a section through a burner according to one embodiment; 
         FIG. 2 : shows a perspective view of the burner from  FIG. 1 , but with the cover removed; 
         FIG. 3 : shows a plan view of a deflecting element of the burner from  FIG. 1 ; 
         FIG. 4 : shows a plan view of the section from  FIG. 1 ; and 
         FIG. 5 : shows a diagram on energy efficiency. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION 
     In the figures the same reference characters refer to identical or functionally identical elements, unless indicated otherwise. 
       FIG. 1  shows a perspective view of a section through a burner  1  according to one embodiment. 
     The burner  1  is for example a component of a gas-heated cooking appliance in the form of a schematically indicated gas hob  2 . The gas hob  2  is designed for use in the home. 
     The burner  1  comprises a lower part  3  and an upper part  4 . The lower and upper part  3 ,  4  together form a base  5  of the burner  1 . A cover  6  is placed on the upper part  4 . 
     The lower part  3  comprises a chamber  7 , on the floor of which a nozzle  11  is arranged. The nozzle  11  is connected via a gas connection  12  of the lower part  3  to a gas supply line (not shown). 
     The upper part  4  comprises a plate  13 , from which a pipe  14  projects downward. One end  15  of the pipe  14  is directed toward the nozzle  11  and is designed to be open in respect thereof. At its other end  16  the pipe  14  is integrally formed with the plate  13  and has an opening to a defined space  17  between the cover  6  and the plate  13 . 
       FIG. 2  shows a perspective view of the burner from  FIG. 1 , but with the cover  6  removed. 
     In  FIG. 2  it can be seen that the plate  13  has flame outlets  21  on its circumference, which entirely define it together with the cover  6 . The flame outlets  21  connect the space  17  (see  FIG. 1 ) to the surrounding area  22 . 
     In  FIGS. 1 and 2  a deflecting element  23  can be seen in each case, which is arranged in the interior space  24  bounded by the pipe  14 . The deflecting element  23  is for example designed in the form of a wire cross. 
       FIG. 3  shows the deflecting element  23  from  FIGS. 1 and 2  in a plan view. 
     The deflecting element  23  comprises two pieces of wire  25 ,  26  made of metal, which are connected to one another in the center. In particular the pieces of wire  25 ,  26  can be formed integrally. The pieces of wire  25 ,  26  can be arranged at an angle of 90° to one another. Further, the pieces of wire  25 ,  26  are firmly connected at their respective ends  27  to the inner wall  31  of the pipe  14 . The deflecting element  23  can also be formed integrally with the inner wall  31 . A respective piece of wire  25 ,  26  has a diameter  32  of for example 1.5 mm. The diameter  33  of the inner wall  31  is for example 11.4 mm. This diameter  33  corresponds to the external diameter of the deflecting element  23 . 
       FIG. 4  shows the section from  FIG. 1  in a plan view. 
     On the basis of  FIG. 4  the precise arrangement of the deflecting element  23  in respect of the longitudinal axis  34  of the pipe  14  can in particular be seen. According to the exemplary embodiment the deflecting element  23  is arranged in the center between the ends  15 ,  16  of the pipe  14 . The correspondingly identical spacings of the deflecting element  23  from the respective ends  15 ,  16  are designated in  FIG. 4  by  35 . However, the deflecting element  23  could also be arranged closed to the end  15 . The pipe  14  can, as shown in  FIG. 4 , have a cross-section which tapers in the direction of the cover  6 . For example, the interior diameter of the pipe  14  in the region of the end  15  can be between 11.8 and 12.2 mm. In the region of the end  16 , in contrast, the internal diameter of the pipe  14  can now be between 10.8 and 11.2 mm. 
     Burnable gas  28  flowing out of the nozzle  11  in the longitudinal direction  34  of the pipe  14  (see  FIG. 1 ) is mixed with primary air  29  in the pipe  14 . The primary air  29  in this case enters the end  15  of the pipe  14  via a radial gap  30  between the end  15  and the nozzle  11 . The mixing of the burnable gas  28  with the primary air  29  is considerably improved by the deflecting element  23 . 
       FIG. 5  shows a diagram on energy efficiency. 
     The white column shows the measured energy efficiency for the burner  1  according to  FIGS. 1-4  without the deflecting element  23 . The energy efficiency was 54.3%. In another experiment the energy efficiency of the burner  1  was determined with the deflecting element  23  (see the hatched column). Surprisingly, the energy efficiency was 59.7%, in other words 5.4% above the embodiment without a deflecting element  23 . 
     Although the invention has here been described on the basis of exemplary embodiments, it can be variably modified.