Oil premix burner

Abstract

An oil premix burner comprising: a combustion element; a burner surface on the outer lateral surface; a distribution chamber below the burner surface; a central oil injection device; a combustion air channel connected to a blower situated upstream as well as an air heat exchanger for the preheating of the combustion air in the area of the burner surface. In each case, the annular space formed between the inner tube and the outer tube of all the double tube elements opens out into an annular-shaped collecting chamber, and the preheated combustion air, starting from the collecting chamber, flows inwards via a swirl-generating device into the area around the oil injection device into the distribution chamber.

What is claimed is: 
     
         1 . An oil premix burner, comprising:
 a combustion element;   a burner surface on an outer lateral surface;   a distribution chamber below the burner surface;   a central oil injection device;   a combustion air channel connected to a blower situated upstream; and   an air heat exchanger for preheating combustion air in an area of the burner surface, the air heat exchanger including multiple double-tube elements distributed over the circumference;   wherein the double-tube elements have parallel flow-through and extend to the combustion element along parallel axes, and wherein each double-tube element has an inner tube and an outer tube having flow-through in series with one another, each double tube element having an entry side of the inner tube connected to the combustion air channel;   wherein the combustion air, in a turnaround zone at an end of each double-tube element away from the oil injection device, enters an annular space formed between the inner tube and the outer tube, and subsequently flows back in the direction of the entry side near the oil injection device;   wherein the annular space formed between the inner tube and the outer tube of each double-tube element opens out into an annular-shaped collecting chamber; and   wherein the preheated combustion air, starting from the collecting chamber, flows inwards via a swirl-generating device into an area around the oil injection device into the distribution chamber.   
     
     
         2 . The oil premix burner as recited in  claim 1 , wherein the swirl-generating device is configured to conduct the flow of the preheated combustion air from the outside of the swirl-generating device to the inside, and wherein the swirl-generating device is ring-shaped and symmetrically to the center of the oil injection device. 
     
     
         3 . The oil premix burner as recited in  claim 2 , wherein the swirl-generating device is configured as an annular disk which (i) is enclosed on both sides in the axial direction by associated limiting walls and (ii) has channels in the radial direction for the combustion air. 
     
     
         4 . The oil premix burner as recited in  claim 2 , wherein the swirl-generating device is configured as an annular disk and, in the circumferential direction, has a uniform wave-shaped construction of alternating channels, wherein wave-shaped outer sides each lie against associated limiting walls, and between wave-shaped internal sides and the limiting walls, lying respectively opposite one another, a channel is provided in each case for the combustion air. 
     
     
         5 . The oil premix burner as recited in  claim 4 , wherein each channel for the combustion air is configured as a flat channel having an essentially rectangular flow-through cross section. 
     
     
         6 . The oil premix burner as recited in  claim 3 , wherein the channels of the swirl-generating device have a radial angle of incidence to the mid-perpendicular within the range of approximately 30 degrees to 75 degrees. 
     
     
         7 . The oil premix burner as recited in  claim 4 , wherein a swirling direction achieved by the swirl-generating device is adjusted based on oil spraying characteristics of the central oil injection device. 
     
     
         8 . The oil premix burner as recited in  claim 7 , wherein the swirling direction of the air flow accelerated using the swirl-generating device substantially corresponds to the swirling direction of the oil spray generated using the central oil injection device. 
     
     
         9 . The oil premix burner as recited in  claim 4 , wherein a cone is provided at a distance from the central oil injection device and concentric with the central oil injection device, the cone forming a transition of one of the limiting walls of the swirl-generating device into the distribution chamber. 
     
     
         10 . The oil premix burner as recited in  claim 9 , wherein the cone extends over at least approximately one-fifth of the length of the distribution chamber and tapers in the flow direction in such a way that an inner entry diameter of the cone near the central oil injection device is at least 5 per cent greater than an inner exit diameter of the cone away from the central oil injection device. 
     
     
         11 . The oil premix burner as recited in  claim 9 , wherein an outer diameter of the swirl-generating device is less than a pitch diameter of the double-tube elements, and wherein an inner diameter of the swirl-generating device is at least equal to the inner entry diameter of the cone about the central oil injection device.