RU147854U1 - GAS-BURNING HEAD FOR BURNERS WITH PRELIMINARY MIXING AND A BURNER SUPPORTED TO THE ABOVE BURNING HEAD - Google Patents

Abstract

1. A gas-burning head (10) for pre-mixed burners, comprising: a main body (11) defining an internal distribution chamber (14) connected to at least one supply pipe for introducing the combustible gas-air mixture (15) inside of said internal distribution chamber (14) and provided with at least one distribution wall (12) containing a plurality of openings (13) through which the combustible gas-air mixture (15) flows from said internal distribution chamber (14) of said main housing (11) into the combustion zone (16) outside the specified main body (11); characterized in that the distribution wall (12) of the specified main body (11) is conical in shape with sections essentially round with respect to planes perpendicular to the central axis (Z) of the cone, and with a curvature directed to the specified internal distribution chamber (14); the specified distribution wall (12) is formed by at least one sheet plate with the specified set of holes (13) obtained in its thickness, and these holes (13) have a size essentially equal to all, and are perpendicular to the conical surface of the specified the sheet plate in the (Y) directions, inclined to the central axis (Z) of the specified cone, the flows of the specified air-gas mixture with substantially equal flow velocities forming tongues of flame inside the specified combustion zone (16), according to ETS equal and symmetrically disposed about the central axis (Z) of said cone, converging to this central axis (Z) together and allow the formation of a stream of hot

Description

Technical field

The present utility model relates to a pre-mix gas burner head and a burner provided with the above burn head according to the introductory part of the corresponding independent claims of the utility model.

The present combustion head and burner belong to types adapted primarily for use in the production of thermodynamic devices, in particular for heating, adapted to generate heat through a stream of exhaust gases to be used in exchangers for the production of thermal energy.

State of the art

In order to increase the productivity of heat generators fed with combustible gas, regardless of whether they are designed to produce hot air, hot water or steam, pre-mixing burners are used more and more often, which differ in the content of preliminary mixing of the combustion air and combustible gas upstream combustion zones. A particular characteristic of these burners is that they are able to provide optimal combustion in a wide range of thermal power, and they also allow to reduce the size of the combustion chambers.

Pre-mixed burners have been on the market for a long time and are mainly used in hot air generators and hot water heaters. The thermal power of one burner usually does not exceed several hundred kilowatts on average; this is due to the technical characteristics of the combustion heads, currently applicable in these burners with preliminary mixing. The range of smooth adjustment of the thermal power of the above burners with currently used combustion heads is also limited; it is not easy, and sometimes impossible, to remove or only reduce the constant noise and the vibration phenomenon that occur, and the adjustment is also not easy. In addition, the currently used combustion heads used in pre-mixed burners completely determine the geometry of the combustion chamber, requiring the use of only one type of it. A common case is the one described in EP 1538395 A1, where the combustion head described here develops a combustion flame that is completely radial, mainly adapted for hot water heaters or in any case for devices that do not have a combustion chamber " with flame inversion. " Also, the life of currently used combustion heads in devices with high thermal power due to the high surface temperature of the head is limited and is much shorter than the average useful life of the device.

From WO 2008/081271 and US 2009/0291402, a burner is known which is provided with several combustion heads for an air-gas mixture, formed by a pair of walls that converge together and are located on each side to form adjacent longitudinally extending channels. The walls are provided with many openings for the passage of air-gas fluid. This solution turned out to be spatially cumbersome, with the same output from combustion and unsuitable for creating a flame shape that allows for an optimized flow of hot gases, in particular for a type of combustion chamber with flame inversion. Indeed, the flame formed in these combustion heads has a main extension parallel to the longitudinal extension of the channels and is not directed in the direction of passage of the hot gases. JP patent S62196517 describes a burner having a combustion head with a pair of walls that are completely similar to those described above.

The closest analogues of the claimed utility model are the solutions known from US Pat. Nos. 2,121,948 and EP 5,79315. These documents disclose burners equipped with one or more burning heads with a conical shape provided with a main hole obtained centrally in the lower part of the cone and fed through pipeline air-gas mixture. The main hole is surrounded by many secondary holes with the same mixture. The main stream exits from the main hole with high speed and high flow rate, while many secondary flows come out of the secondary holes with lower flow rate, much lower than that of the main hole; the main purpose of such small flows is to stabilize the flame created by the main channel. Secondary and main supply channels are made in a housing formed in a special way. The channels direct the fluid output with their passage in parallel or at an angle to the axis of symmetry of the cone. The openings at the ends of the channels are affected by a pressure drop in the same channel, i.e. in distribution chambers obtained in the same shaped burner body. The resulting shape of the entire flame is very much affected by the pressure of the air / gas mixture. Given that the total resulting flame is mainly obtained through the main flow of the air / gas mixture, it does not have a large combustion surface area and therefore is not suitable for keeping nitrogen oxide emissions at a low level.

Another disadvantage of these conical heads for burners is the high cost of construction, in particular for the installation of the resulting feed pipelines in a certain shape of the housing.

Utility Model Summary

In this context, therefore, the main objective of this utility model is to overcome the already known drawbacks of the prior art that are described above by introducing a pre-mixed burner head for burners that can separately burn even more than 500 kilowatts and which have a continuously variable adjustment range thermal power from about 5 to 100%, without noise and, especially, resonance problems. Indeed, due to the partial curvature of the conical surface for the exit of the combustible gas-air mixture, the self-feeding effect can be used and a stable flame can be obtained under various conditions of the heat flow of combustion, with all types of combustible gas.

Another objective of the present utility model is to present a burner whose combustion head is especially adapted to its combustion chamber of the “flame inversion” type. The longitudinal stability of the flame due to the partial curvature of the conical surface for the distribution of the combustible gas-air mixture actually allows for the use of cylindrical combustion chambers, in which flame inversion is obtained in the combustion chamber itself, complete optimization of the heat exchange surfaces and the removal of combustion products.

Another objective of this utility model is to provide a pre-mixed burner head for burners that has a long service life and which differs from the classic so-called “radial heads”, to a greater or lesser extent coated with metal or ceramic materials. Indeed, due to the partial curvature of the conical surface for supplying the combustible gas-air mixture present in the combustion head according to the utility model, the development and shape of the flame are such as not to heat the housing of the combustion head itself, providing greater stability and durability over time .

To solve the above problems, the claimed utility model provides a gas-burning head for pre-mixed burners, comprising: a main body defining an internal distribution chamber connected to at least one supply pipe for introducing a combustible gas-air mixture into said internal distribution chamber and provided with at least one distribution wall comprising a plurality of openings through which a combustible gas-air mixture flows from said internal a distribution chamber of said main body to a combustion zone outside of said main body; characterized in that the distribution wall of said main body is conical in shape with sections substantially round with respect to planes perpendicular to the central axis of the cone and with a curvature directed towards said internal distribution chamber; the specified distribution wall is formed by at least one sheet plate with the specified set of holes obtained in its thickness, and these holes have a size substantially equal to all, and are perpendicular to the conical surface of the specified sheet plate in directions obliquely to the Central axis of the specified cone flows of the specified air-gas mixture with essentially equal flow rates, forming flames inside the specified combustion zone, essentially equal to and p memory location symmetric about the center axis of said cone, converging to this central axis and allow the formation with the flow of hot exhaust gases with a maximum rate of flow of said central axis.

In one of the preferred embodiments of the inventive gas-burning head, the conical wall defines the shape of the truncated cone.

In another preferred embodiment of the gas-burning head, the conical wall comprises two conical plates, each of which has a plurality of holes parallel and spaced apart along the length of the longitudinal axis.

In another preferred embodiment of the gas-burning head, the cross-sections of the plurality of openings of the conical wall for passing the combustible gas-air mixture are of different sizes throughout the conical shape along the longitudinal axis.

In another preferred embodiment of the gas-burning head, the openings from the plurality of openings of the conical wall for passing the combustible gas-air mixture are made along the circumferences of the conical wall, spaced apart from each other with a varying inclination along the direction of the longitudinal axis.

The claimed utility model also provides a burner for air-gas mixtures containing a gas-burning head and a combustion chamber, inside which is located the specified combustion head, characterized in that said combustion chamber is provided with axial symmetry centered on the axis of the cone of the specified combustion head, while, in particular , it is made of a cylindrical shape, and provided with a lower wall facing the specified distribution wall, and allows a change in the direction of movement of the exhaust gases of the specified mixture ozduh / gas "180 degrees due to their direction towards the opposite wall of the base on which the head is provided for burning, with about a base wall section to obtain output exhaust gas from the outside of said partition wall.

Description of graphic materials

A brief description of the graphic materials

The technical characteristics of the solution according to the task and the proposed goals can be clearly found in the contents of the utility model formula presented below, and their advantages will become clearer in the detailed description of one embodiment, according to the solution depicted as a non-limiting example in the attached set of graphic materials on which:

figure 1 shows a preferred non-limiting embodiment of a gas-burning head for pre-mixed burners.

FIG. 2 shows a preferred non-limiting embodiment of a pre-mixed gas burner head applied to a “flame inversion” combustion chamber.

Detailed Description of a Preferred Embodiment

In the set of graphic materials, the position (10) denotes a gas-burning head for burners with preliminary mixing in its entirety.

It contains a main body (11) adapted for receiving combustible gas-air mixture (15), which is provided by an internal distribution chamber (14) for combustible gas-air mixture (15) and at least one distribution wall (12 ) The latter is provided by a series of holes (13) through which a mixture of “combustible gas-air” (15) flows from the distribution chamber (14). The distribution wall (12) of the main body (11) has a conical shape with sections substantially round with respect to planes perpendicular to the central axis (Z) of the cone and with a curvature directed towards the internal distribution chamber (14).

Such a distribution wall (12) is formed by at least one sheet metal plate with the aforementioned set of holes (13) obtained in its thickness. The latter (13) have a size that is essentially equal for all, and are perpendicular to the conical surface of the specified sheet plate in the (Y) directions, at an angle to the central axis (Z) of the cone, the air-gas mixture flows with substantially equal flow rates and allow formation of flames in the combustion zone (16), which are essentially equal and are located symmetrically around the central axis (Z) of the cone, and also converge to this central axis (Z) to together form a stream of hot exhaust gases with max total flow velocity near the central axis (Z) of the cone.

The above-mentioned combustion head (10) limits the combustion zone (16) outside the specified main body (11), where the ignition of the combustible gas-air mixture occurs and where the flame (17) is formed, with the chamber (19) being pulled along the longitudinal axis (18) combustion, in particular coinciding with the central axis of the cone (Z) of the head (12).

The sheet plate may advantageously be in the form of a mesh.

Figure 2 shows the combustion chamber (19) with "flame inversion", while the gas-burning head for pre-mixed burners (10) is connected to this chamber.

Explanation of FIG. 1 and FIG. 2

Figure 1 shows that the main body (11) receives into the distribution chamber (14) a mixture (15) of “combustible gas-air”, which is pre-mixed in the system upstream of the body itself. The internal distribution chamber (14) thus contains a mixture of “combustible gas-air”, which is under pressure with respect to the combustion zone (16). Through holes (13) made in a conical surface (12) with a curvature directed to the distribution chamber (14), then a stream of air-gas mixture is released, which is instantly ignited by an ignition device (not shown) in the area bounded by the conical surface (12 ) defined as a combustion zone (16). Single flows exiting the openings (13) pass in directions (Y) that are inclined with respect to the central axis (Z) of the symmetry of the cone. In other embodiments not presented here, in order to change the range of thermal power that can be developed by the burning head (10), the surface shape (12) can take various configurations, mainly including the shape of a truncated cone.

In other embodiments not presented here, the conical wall (12) comprises two conical plates, each having a plurality of holes parallel and spaced apart along the length of the longitudinal axis (18).

The size of the holes (13) is usually the same throughout the conical shape along the longitudinal axis. The flow rate of the air-gas mixture through each individual hole (13) is proportional to the area of its passage and the pressure present in the distribution chamber (14). In other embodiments not shown here, to allow variation in the range of thermal power that can be developed by the burning head (10), the size of the holes (13) can vary along the conical shape along the longitudinal axis. In other embodiments, not shown here, to allow changing the range of thermal power that can be developed by the burning head (10), the cross-section of many holes (13) of the conical wall (12), for the passage of the mixture (15) “combustible gas-air” are made around the circumferences of the conical wall (12), which are spaced from each other with a varying slope along the direction of the longitudinal axis (18). In other embodiments not shown here, to allow the range of thermal power that can be developed by the combustion head (10) to vary, the degree of taper of the surface (12) may vary.

Figure 2 shows that the gas-burning head (10) of the pre-mixed burners is connected to the "flame inversion" combustion chamber (19). The flame (17) develops and spreads in the direction of the lower wall (21) of the combustion chamber (19), while this wall is opposite to the wall (23) of the base where the burning head (10) is installed. When the combustion products (20) reach close proximity to this wall (21), they change direction by 180 ° to bring down into the flue gas exchanger system through at least one outlet section (22) located in close proximity to the initial flame front ( 17), i.e. walls (23) of the base. In more detail, this outlet section (22) can be obtained in a predominantly cylindrical side wall (24), which connects the bottom wall (21) to the base wall (23), in the latter, or it can be obtained directly using perimeter holes in the wall (23) of the base.

Claims (6)

1. A gas-burning head (10) for pre-mixed burners, comprising: a main body (11) defining an internal distribution chamber (14) connected to at least one supply pipe for introducing a mixture of “combustible gas-air” into said internal distribution chamber (14) and provided with at least one distribution wall (12) containing a plurality of openings (13) through which the combustible gas-air mixture (15) flows from said internal distribution chamber (14) of said main body (11) into a combustion zone (16) outside said main body (11) ); characterized in that the distribution wall (12) of said main body (11) is conical in shape with sections substantially round with respect to planes perpendicular to the central axis (Z) of the cone and with a curvature directed towards said internal distribution chamber (14) ); the specified distribution wall (12) is formed by at least one sheet plate with the specified set of holes (13) obtained in its thickness, and these holes (13) have a size essentially equal to all, and are perpendicular to the conical surface of the specified the sheet plate in directions (Y) at an angle to the central axis (Z) of the specified cone, the flows of said air-gas mixture with substantially equal flow velocities forming tongues of flame inside said combustion zone (16), according to ETS equal and symmetrically disposed about the central axis (Z) of said cone, converging to this central axis (Z) together and allow the formation of a stream of hot exhaust gases with a maximum flow rate of said central axis (Z). 2. The gas-burning head (10) for pre-mixed burners according to claim 1, characterized in that the conical wall (12) determines the shape of the truncated cone. 3. The gas-burning head (10) for pre-mixed burners according to claim 1 or 2, characterized in that the conical wall (12) contains two conical plates, each of which has many holes parallel and spaced from each other along the longitudinal axis (18). 4. The gas-burning head (10) for pre-mixed burners according to claim 1, characterized in that the sections of the plurality of openings (13) of the conical wall for passing the combustible gas-air mixture have different sizes along the conical shape along the longitudinal axis. 5. The gas-burning head (10) for pre-mixed burners according to claim 1, characterized in that the openings from the plurality of openings (13) of the conical wall for passing the combustible gas-air mixture are made along the circumferences of the conical wall spaced from each other varying slope along the direction of the longitudinal axis. 6. A burner for air-gas mixtures containing a gas-burning head (10) according to claim 1 and a combustion chamber (19), inside which a specified combustion head is located, characterized in that said combustion chamber (19) is provided with axial symmetry centered on the axis the cone of the specified combustion head (10), in particular, it is made of a cylindrical shape, and provided with a lower wall (21) facing the specified distribution wall (12), and allows a change in the direction of movement of the exhaust gases (20) of the specified mixture "air / gas "at 180 ° per second even their directions in the direction of the opposite wall (23) of the base on which the burning head (10) is provided, while near such wall (23) of the base, outlet sections (22) for exhaust gases are obtained outside the specified distribution wall (12).

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