NL2033134B1 - Premix gas burner deck plate - Google Patents
Premix gas burner deck plate Download PDFInfo
- Publication number
- NL2033134B1 NL2033134B1 NL2033134A NL2033134A NL2033134B1 NL 2033134 B1 NL2033134 B1 NL 2033134B1 NL 2033134 A NL2033134 A NL 2033134A NL 2033134 A NL2033134 A NL 2033134A NL 2033134 B1 NL2033134 B1 NL 2033134B1
- Authority
- NL
- Netherlands
- Prior art keywords
- gas burner
- premix
- premix gas
- cover plate
- gas
- Prior art date
Links
- 238000002485 combustion reaction Methods 0.000 claims abstract description 67
- 238000009826 distribution Methods 0.000 claims abstract description 54
- 238000012546 transfer Methods 0.000 claims abstract description 43
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 35
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 34
- 238000004512 die casting Methods 0.000 claims description 51
- 238000000034 method Methods 0.000 claims description 45
- 239000011248 coating agent Substances 0.000 claims description 22
- 238000000576 coating method Methods 0.000 claims description 22
- 239000000463 material Substances 0.000 claims description 22
- 238000004519 manufacturing process Methods 0.000 claims description 15
- 238000005260 corrosion Methods 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 5
- 230000002093 peripheral effect Effects 0.000 claims 4
- 239000004411 aluminium Substances 0.000 abstract description 31
- 239000007789 gas Substances 0.000 description 620
- 230000006835 compression Effects 0.000 description 18
- 238000007906 compression Methods 0.000 description 18
- 230000035882 stress Effects 0.000 description 17
- 238000003754 machining Methods 0.000 description 10
- 230000007797 corrosion Effects 0.000 description 7
- 238000013461 design Methods 0.000 description 7
- 206010016754 Flashback Diseases 0.000 description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 6
- 239000005864 Sulphur Substances 0.000 description 6
- 239000002737 fuel gas Substances 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000004576 sand Substances 0.000 description 5
- 230000003746 surface roughness Effects 0.000 description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000011144 upstream manufacturing Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000005553 drilling Methods 0.000 description 3
- 238000007528 sand casting Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000005242 forging Methods 0.000 description 2
- 239000003205 fragrance Substances 0.000 description 2
- 238000003698 laser cutting Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details, e.g. noise reduction means
- F23D14/48—Nozzles
- F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details, e.g. noise reduction means
- F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
- F23D14/82—Preventing flashback or blowback
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
- F23C2900/9901—Combustion process using hydrogen, hydrogen peroxide water or brown gas as fuel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2203/00—Gaseous fuel burners
- F23D2203/10—Flame diffusing means
- F23D2203/102—Flame diffusing means using perforated plates
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
- F23D2900/00018—Means for protecting parts of the burner, e.g. ceramic lining outside of the flame tube
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Gas Burners (AREA)
Abstract
The invention pertains to a premix gas burner deck plate, comprises: - a gas passage area, and - a heat transfer area, wherein the premix gas burner deck plate has a first plate thickness in the gas passage area and a second plate thickness in the heat transfer area, which second plate thickness is larger than the first plate thickness, and Wherein the premix gas burner deck plate comprises a gas outflow channel which is adapted to during use supply premix gas to a combustion zone, which gas outflow channel is arranged in the gas passage area and extends through the first plate thickness from the distribution chamber side of the premix gas burner deck plate to the combustion zone side of the premix gas burner deck plate, and wherein the premix gas burner deck plate is made of cast aluminium.
Description
P35957NLOO/NBL
Premix gas burner deck plate
The invention pertains to a premix gas burner deck plate, a premix gas burner comprising the premix gas burner deck plate, a heating appliance comprising the premix gas burner and a method for manufacturing the premix gas burner deck plate.
A premix gas burner deck plate in accordance with the invention is of the type that is used in premix gas burners for heating appliances such as heater systems for buildings or domestic hot water systems. Traditionally, such premix gas burners use a premix burner gas that contains for example methane mixed with air. Currently, in order to reduce carbon dioxide emissions, developments are going on to add hydrogen to the premix burner gas, or even to replace the methane by hydrogen entirely.
In use, the premix gas burner deck plate deck of a known premix gas burner often reaches a high maximum temperature of at least 500°C, often even up to more than 800°C.
High burner deck temperatures increase the risk of flashback, in particular if the fuel gas is or contains hydrogen, as the hot burner deck may ignite the premix gas inside the burner, upstream of the premix gas burner deck plate, which is highly undesirable from a safety point of view. In addition, the premix gas burner deck plates of the type to which the invention pertains are often used in modulating heater systems, in which the thermal load on the burner varies significantly during relatively short time spans. This causes changes in the burner deck temperature, and therewith the amount of thermal expansion and the magnitude of thermal stresses in the burner deck of the premix gas burner. These varying stresses are a major cause of thermal fatigue. Often, special designs are necessary to deal with the varying temperatures.
The invention aims to provide an improved premix gas burner deck plate, which has a reduced risk of flashback.
This object is obtained by a premix gas burner deck plate, which premix gas burner deck plate has a distribution chamber side and a combustion zone side, which distribution chamber side and combustion zone side are located on opposite sides of the premix gas burner deck plate, which premix gas burner deck plate further comprises: - a gas passage area, and - a heat transfer area,
wherein the premix gas burner deck plate has a first plate thickness in the gas passage area and a second plate thickness in the heat transfer area, which second plate thickness is larger than the first plate thickness, and wherein the premix gas burner deck plate comprises a gas outflow channel which is adapted to during use supply gas to a combustion zone, which gas outflow channel is arranged in the gas passage area and extends through the first plate thickness from the distribution chamber side of the premix gas burner deck plate to the combustion zone side of the premix gas burner deck plate, and wherein the premix gas burner deck plate is made of cast aluminium.
The premix gas burner deck plate according to the invention has a distribution chamber side and a combustion zone side, which distribution chamber side and combustion zone side are located on opposite sides of the premix gas burner deck plate. When the premix gas burner deck plate is arranged in a premix gas burner, the distribution chamber side of the premix gas burner deck plate faces towards a gas distribution chamber of the premix gas burner, 50, in upstream direction of the flow of the premix gas. When the premix gas burner deck plate is arranged in a premix gas burner, the combustion zone side of the premix gas burner deck plate faces towards a combustion zone in which the actual combustion of the premix gas takes place, so, in downstream direction of the flow of the premix gas.
The premix gas burner deck plate according to the invention comprises a gas passage area and a heat transfer area. Premix gas passes from the distribution chamber side of the premix gas burner deck plate to the combustion zone side of the premix gas burner deck plate via the gas passage area. The heat transfer area is designed for effective heat transfer, with the aim of avoiding high burner deck temperatures in the premix gas burner deck plate.
The premix gas burner deck plate has a first plate thickness in the gas passage area and a second plate thickness in the heat transfer area. The second plate thickness is larger than the first plate thickness. For example, the first plate thickness is 0.5 millimeters (mm) up to and including 1.5 millimeters (mm), for example 1 millimeter (mm). For example, the second plate thickness is 1.5 millimeters (mm) to 10 millimeters (mm), e.g. 2 mmilimeters (mm) up to and including 7 millimeters (mm), for example 2.5 millimeters (mm) to 6 milolimeters (mm) 5 millimeters (mm), e.g. 5 millimeters (mm) or 3 millimeters (mm). Of course, in case the first thickness is 1.5 mm, the second thickness is more than 1.5 mm. For example, the first thickness is 1 mm and the second thickness is 3 mm.
The premix gas burner deck plate comprises a gas outflow channel which is adapted to during use supply premix gas to the combustion zone, in which combustion zone the combustion of the premix gas takes place during use of the premix gas burner deck plate in a premix gas burner. The combustion zone is usually present adjacent to but just outside of the premix gas burner in which the premix gas burner deck plate is arranged. The gas outflow channel is arranged in the gas passage area and extends through the first plate thickness from the distribution chamber side of the premix gas burner deck plate to the combustion zone side of the premix gas burner deck plate.
For example, the gas outflow channel has a circular cross-sectional shape, with a diameter that is either constant or varies over the length of the gas outflow channel. In case the diameter varies over the length of the gas outflow channel, the gas outflow channel is for example tapered. The taper angle of the gas outflow channel is optionally at least 6°, for example at least 9°, optionally at least 12°. The diameter at an end of the gas outflow channel, e.g. at the end with the smallest diameter, is for example 0.6 mm — 1.0 mm, e.g. 0.8 mm. In case the diameter is constant over the length of the gas outflow channel, the diameter at an end of the gas outflow channel 12 is for example 0.6 mm — 1.0 mm, e.g. 0.8 mm.
In accordance with the invention, the premix gas burner deck plate is made of cast aluminium, e.g. pressure die cast aluminium (including high pressure die cast aluminium) or sand cast aluminium. Cast aluminium has a high thermal conductivity, which makes that it is effective in transferring heat away from the premix gas burner deck plate.
Cast aluminium is an example of a metal having a thermal conductivity coefficient at room temperature of at least 80 W/(mK) and having a Young'’s modulus for tension at room temperature of 150GPa or less. Alternatively, instead of aluminium, another metal having a thermal conductivity coefficient at room temperature of at least 80 W/(mK) and having a
Young's modulus for tension at room temperature of 150GPa or less can be used for the premix gas burner deck plate according to the invention. The Young's modulus for tension at room temperature of 150GPa or less allows that material stresses remain at levels that can be considered acceptable for a viewpoint of thermal fatigue.
Instead of cast aluminium, another metal having the same properties in terms of at least thermal conductivity and Young's modulus at room temperature with respect to compression and to tension can be used.
Examples of (aluminium) materials that are suitable for use in the premix burner deck plate according to the invention are EN-AC44300 (EN AC-AISi12(Fe), Werkstoff no. 3.2582),
EN-AC 42100 (EN AC Si7Mg0.3, Werkstoff no. 3.2371, LM25), EN-AC43000 (EN AC-AL
Si10Mg(a), Werkstoff no. 3.2381).
Tests of the premix gas burner deck plate according to the invention have indicated that the premix gas burner deck plate according to the invention performs well with respect to the risk of the occurrence of flash back.
It is suspected that this may be due to that the relatively small plate thickness near the gas outflow channels prevents significant local cooling by the premix gas flowing through the gas outflow channel. The relatively thin plate near the gas outflow channels is not so effective in terms of heat transfer (that requires a larger plate thickness), so the gas passage area through which the gas outflow channels extend remains rather hot. As a consequence, the premix gas is not heated very much during its passage through the gas outflow channel. So, the premix gas leaves the gas outflow channel and enters the combustion zone at a relatively low temperature.
The flame speed which occurs during combustion is directly linked to the premix gas temperature. A lower temperature of the premix gas results in a lower flame speed, which makes that the actual flames will be relatively far from the premix burner deck plate. This reduces the total heat load on the premix gas burner deck plate. This, together with the larger place thickness in the heat transfer area of the premix burner deck plate, makes that the overall temperature of the premix gas burner deck plate remains relatively low, despite the warmer and thinner gas passage area. This relatively low overall burner deck temperature could be the explanation for the good performance in terms of the risk of the occurrence of flash back.
It is suspected that the use of cast aluminium (or another metal material with similar relevant properties in terms of e.g. thermal conductivity and Young’s modulus for tension) helps to achieve this good performance because of its relatively high thermal conductivity, which is useful for the effectiveness of the heat transfer areas.
Tests have also shown that the premix gas burner deck plate according to the invention can be manufactured well and at relatively limited costs from the cast aluminium, in particular pressure die cast aluminium, even when it is desired to limit the number and/or intensity of further manufacturing steps {such as drilling or machining).
In an embodiment of the premix gas burner deck plate in accordance with the invention, the gas passage area comprises a plurality of gas outflow channels.
Preferably, the gas outflow channels in the gas passage area are arranged in a predetermined pattern, e.g. in a predetermined pattern that allows for or is even optimised for the combustion of a premix gas in which the fuel gas is or contains hydrogen.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the premix gas burner deck plate comprises a plurality of gas passage areas, and each gas passage area comprises at least one gas outflow channel.
Optionally, at least one gas passage area comprises a plurality of gas outflow channels.
Optionally, multiple gas passage areas comprise a plurality of gas outflow channels
Optionally, all gas passage areas comprise a plurality of gas outflow channels.
Optionally, multiple gas passage areas are grouped together in a gas discharge zone.
Optionally, multiple or all gas passage areas are arranged in a central gas discharge zone, which is for example arranged at a distance from a circumferential edge of the premix gas burner deck plate, for example in the center of the premix gas burner deck plate.
Optionally, the premix gas burner deck plate comprises a plurality of gas discharge zones, wherein multiple gas discharge zones comprise multiple gas passage areas, and wherein optionally all gas discharge zones comprise multiple gas passage areas.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the premix gas burner deck plate has a circumferential edge, and the premix gas burner deck plate comprises a plate rim area adjacent to at least a part of the circumferential edge. In this embodiment the premix gas burner deck plate has a third plate thickness in the plate rim area, which third plate thickness is larger than the first plate thickness, optionally equal to or larger than the second plate thickness.
So, in this embodiment, the premix gas burner deck plate has a plate rim area that is thicker than the plate thickness in the gas passage areas. Optionally, in the plate rim area the premix gas burner deck plate is as thick or even thicker than in the heat transfer areas of the premix gas burner deck plate. This supports the transfer of heat away from the premix gas burner deck plate during use, which in turn helps to keep the premix gas burner deck plate relatively cool and therewith reduces the risk of flashback.
Optionally, in this embodiment, the premix gas burner deck plate further comprises a plurality of gas passage areas, and each gas passage area comprises at least one gas outflow channel. Optionally, at least one gas passage area comprises a plurality of gas outflow channels. Optionally, multiple gas passage areas comprise a plurality of gas outflow channels. Optionally, all gas passage areas comprise a plurality of gas outflow channels.
Optionally, multiple gas passage areas are grouped together in a gas discharge zone, which gas discharge zone is arranged closer to a center of the premix gas burner deck plate than the plate rim area. Optionally, multiple or all gas passage areas are arranged in a central gas discharge zone, which central gas discharge zone is arranged closer to a center of the premix gas burner deck plate than the plate rim area.
Optionally, the plate rim area extends along the entire circumference of the premix gas burner deck plate. Optionally, in that case, the gas passage area or multiple gas passage areas or all gas passage areas is/are arranged in a central gas discharge zone are surrounded by the plate rim area.
In an embodiment of the premix gas burner deck plate according to the invention, the premix gas burner deck plate comprises multiple heat transfer areas.
Optionally, multiple heat transfer areas are in thermal contact with each other.
Optionally, all heat transfer areas are in thermal contact with each other.
In an embodiment of the premix gas burner deck plate in accordance with the invention, at least one gas outflow channel is tapered.
So, in this embodiment, the cross-sectional size of the gas outflow channel varies over the length of the gas outflow channel, in such a way that it either increases or decreases from one end of the gas outflow channel to the other end of the gas outflow channel. For example, if the gas outflow channel has a circular cross-section, the diameter of that circular cross- section is larger on one end of the gas outflow channel than on the other end of the gas outflow channel.
For example, the tapered gas outflow channel widens (or, in case of multiple tapered gas outflow channels: the tapered gas outflow channels widen) from the combustion zone side of the premix gas burner deck plate to the distribution chamber side of the premix gas burner deck plate. Good burner deck performance has been observed with this configuration.
Optionally, in this embodiment, the premix gas burner deck plate comprises a plurality of gas outflow channels. Optionally, multiple gas outflow channels of the plurality of gas outflow channels are tapered. Optionally, all gas outflow channels of the plurality of gas outflow channels are tapered.
An advantage of this embodiment is that a premix gas burner deck plate in accordance with this aspect of the invention contributes to easy removal of the premix gas burner deck plate from a die when the premix gas burner deck plate is made by pressure die casting and the gas outflow channels are formed in the pressure die casting process.
In an embodiment of the premix gas burner deck plate in accordance with the invention, a passage rim area is provided around at least one gas passage area, and the premix gas burner deck plate has a fourth plate thickness in the passage rim area. The fourth plate thickness is larger than the first plate thickness, optionally equal to or larger than the second plate thickness. Optionally, in case a plate rim area is present, the fourth plate thickness is equal to the third plate thickness.
It is suspected that this contributes to obtaining the desired temperature distribution over the premix gas burner deck plate during use.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the combustion zone side of the premix gas burner deck plate is planar. So, in this embodiment, the combustion zone side of the premix gas burner deck plate is devoid of protrusions and indents.
It is suspected that this contributes to obtaining a relatively low burner deck temperature of the premix gas burner deck plate during use.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the premix gas burner deck plate is manufactured by machining a cast aluminum plate.
For example, the final thickness of the gas passage area or gas passage areas is obtained by machining and the gas outflow channel or gas outflow channels is/are formed by drilling, punching or laser cutting. Optionally, the final thickness of the heat transfer area(s) is obtained by machining as well.
In this embodiment, the material of the premix gas burner deck plate has a structure which is typical for cast parts which are later machined to the desired shape.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the premix gas burner deck plate is manufactured by forging and/or pressing a cast aluminum plate.
Optionally, the rough shape of the premix gas burner deck plate is obtained by forging and/or pressing, and the final thickness of the gas passage area or gas passage areas is obtained by machining and the gas outflow channel or gas outflow channels is/are formed by drilling, punching or laser cutting. Optionally, the final thickness of the heat transfer area(s) is obtained by machining as well.
In this embodiment, the material of the premix gas burner deck plate has a structure which is typical for cast parts which are later forged/pressed and then machined to the desired shape.
In an embodiment of the premix gas burner deck plate in accordance with the invention, at least the heat transfer area(s) and/or the gas passage area(s) of the premix gas burner deck plate are manufactured by a pressure die casting process, for example a high pressure die casting process.
In this embodiment, the premix gas burner deck plate is generally formed in a pressure die casting process. For example, different material thicknesses are provided for the gas passage area(s) and the heat transfer area(s). Optionally, the pressure die cast premix gas burner deck plate is machined after pressure die casting in order to make sure the required manufacturing tolerances are met, but in this embodiment the general shape of the premix gas burner deck plate is obtained by pressure die casting.
In this embodiment, the material of the premix gas burner deck plate has a structure which is typical for pressure die cast parts.
Optionally, in this embodiment, also the gas outflow channel(s) of the premix gas burner deck plate is/are formed in the pressure die casting process. Optionally, a plurality of the gas outflow channels of the premix gas burner deck plate is formed in the pressure die casting process. Optionally, all gas outflow channels of the premix gas burner deck plate are formed inthe pressure die casting process.
The design of the premix gas burner deck plate is suitable for manufacturing by a pressure die cast process, e.g. a high pressure die cast process. This allows the premix gas burner deck plate according to the invention to be manufactured at relatively low costs and relatively high speeds, in particular when single shot (high) pressure die casting is used. The premix gas burner deck plate according to the invention allows manufacturing using single shot pressure die casting, e.g. single shot high pressure die casting. Optionally, the die comprise multiple mould cavities so that multiple premix gas burner deck plates can be cast in one single shot.
In this embodiment, the material of the premix gas burner deck plate has a structure which is typical for pressure die cast parts.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the premix gas burner deck plate comprises a plurality of gas passage areas, and each gas passage area comprises at least one gas outflow channel, and multiple gas passage areas are arranged in a gas discharge zone. In this embodiment, the premix gas burner deck plate further has a circumferential edge. The premix gas burner deck plate further comprises a plate rim area adjacent to at least a part of the circumferential edge and at least partly surrounding the gas discharge zone. The premix gas burner deck plate has a third plate thickness in the plate rim area, the third plate thickness being larger than the first plate thickness, optionally equal to or larger than the second plate thickness.
This embodiment is particularly suitable for use in a premix gas burner which is designed in such a way that during use the gas discharge zone is subjected to compression stress. The arrangement of the gas discharge zone with the gas passage areas with relatively small local plate thickness in combination with the plate rim area with larger plate thickness allows to design the premix gas burner such that the plate rim area stays relatively cool and the gas discharge area is relatively warm. In addition, the thicker plate rim area provides additional strength.
Thermal expansion of the gas discharge area is this way limited, which results in compression stresses in the gas discharge area of the premix gas burner deck plate.
Compression stresses are far less likely to induce thermal fatigue cracking than tensile stresses, so having compression stresses in the area where the gas outflow channels (and therefore the stress concentrations due to holes in the premix gas burner deck plate) is likely to contribute to a longer life span of the premix gas burner deck plate from a fatigue point of view. In addition, tests carried out by the applicant seem to suggest that the Young's modulus for compression (sometimes also referred to in the art as compression modulus or elasticity modulus for compression) of cast aluminium (e.g. pressure die cast aluminium or sand cast aluminium) is significantly lower than the Young's modulus for tension, even as much as 1.5 — 2 times lower, up to 3 times lower. As a result of this, the compression stresses in the gas discharge area can be expected to be relatively low. This also contributes to a longer life span of the premix gas burner deck plate from a fatigue point of view.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the premix gas burner deck plate is at least partly provided with a coating, e.g. an anti- corrosion coating. For example, a coating is used which provides protection against sulphur induced corrosion. Sulphur containing substances are sometimes added to fuel gas as odorants, but they may cause corrosion of metals, in particular when they are combusted with oxygen, and react with water H2SO, is formed, which can be highly corrosive.
Optionally, the coating is present at least on a part of the combustion zone side of the premix gas burner deck plate and/or on an inner wall of the gas outflow channel.
Optionally, a surface roughness is provided on the premix gas burner deck plate prior to applying the coating, e.g. during a pressure die casting process or sand casting process in which the premix gas burner deck plate is formed.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the premix gas burner deck plate comprises a curved portion having a radius of curvature, and multiple gas outflow channels are provided in the curved portion, each of the gas outflow channels in the curved portion having a longitudinal axis. In this embodiment, the longitudinal axes of all gas outflow channels in the curved portion are parallel to each other.
An advantage of this embodiment is that a premix gas burner deck plate in accordance with this aspect of the invention contributes to easy removal of the premix gas burner deck plate from a die when the premix gas burner deck plate is made by pressure die casting and the gas outflow channels are formed in the pressure die casting process.
Optionally, the longitudinal axis of at least one of the multiple gas outflow channels in the curved portion extends in the radial direction of the radius of curvature.
In an embodiment of the premix gas burner deck plate in accordance with the invention, multiple gas outflow channels are provided in the premix gas burner deck plate, each of the gas outflow channels having a longitudinal axis. In this embodiment, the longitudinal axes of all gas outflow channels are parallel to each other.
An advantage of this embodiment is that a premix gas burner deck plate in accordance with this aspect of the invention contributes to easy removal of the premix gas burner deck plate from a die when the premix gas burner deck plate is made by pressure die casting and the gas outflow channels are formed in the pressure die casting process.
In an embodiment of the premix gas burner deck plate in accordance with the invention, the gas outflow channel has an inner wall and the gas passage area has an outer surface at the distribution chamber side of the premix gas burner deck plate, and the inner wall of the gas outflow channel meets the outer surface of the gas passage area at the distribution chamber side of the premix gas burner deck plate via a rounded edge.
Optionally, multiple gas outflow channels each have an inner wall and the gas passage area has an outer surface at the distribution chamber side of the premix gas burner deck plate, and the inner wall of each gas outflow channel meets the outer surface of the gas passage area at the distribution chamber side of the premix gas burner deck plate via a rounded edge.
Optionally, all gas outflow channels each have an inner wall and the gas passage area has an outer surface at the distribution chamber side of the premix gas burner deck plate, and the inner wall of each gas outflow channel meets the outer surface of the gas passage area at the distribution chamber side of the premix gas burner deck plate via a rounded edge.
It is suspected that this embodiment contributes to further reducing the risk of flashback, possibly because a smooth flow of premix gas into the gas outflow channel(s) is obtained and negative local pressure at the entrance into the gas outflow channel(s) is reduced or avoided.
The invention further pertains to a premix gas burner comprising a premix gas burner deck plate according to the invention.
In an embodiment of the premix gas burner in accordance with the invention, the premix gas burner comprises a gas distribution chamber, which gas distribution chamber is at least partly delimited by the premix gas burner deck plate.
For example, the premix gas burner in this embodiment further comprises a premix gas supply which is adapted to supply premix gas to the gas distribution chamber.
From the gas distribution chamber, the premix gas flows through the gas outflow channel(s) of the premix gas burner deck plate to the combustion zone, where the combustion of the premix gas takes place.
Optionally, a gas distributor is arranged in the gas distribution chamber, in order to equally distribute the premix gas over multiple gas outflow channels of the premix gas burner deck plate.
In an embodiment of the premix gas burner in accordance with the invention, a premix gas burner deck plate is used which comprises a plurality of gas passage areas, and each gas passage area comprises at least one gas outflow channel, and multiple gas passage areas are arranged in a gas discharge zone. In this embodiment, the premix gas burner deck plate further has a circumferential edge. The premix gas burner deck plate further comprises a plate rim area adjacent to at least a part of the circumferential edge and at least partly surrounding the gas discharge zone. The premix gas burner deck plate has a third plate thickness in the plate rim area, the third plate thickness being larger than the first plate thickness, optionally equal to or larger than the second plate thickness.
In this embodiment, the premix gas burner deck plate is mounted into the premix gas burner in such a way that during use the gas discharge zone is subjected to compression stress.
The arrangement of the gas discharge zone with the gas passage areas with relatively small local plate thickness in combination with the plate rim area with larger plate thickness allows to design the premix gas burner such that the plate rim area stays relatively cool and the gas discharge area is relatively warm. In addition, the thicker plate rim area provides additional strength.
Thermal expansion of the gas discharge area is this way limited or even prevented, which results in compression stresses in the gas discharge area of the premix gas burner deck plate.
In addition, in this embodiment, optionally the mounting of the premix gas burner deck plate in the premix gas burner is adapted to (of even optimised to) ensure that indeed compression stress is obtained in the gas discharge zone.
Compression stresses are far less likely to induce thermal fatigue cracking than tensile stresses, so having compression stresses in the area where the gas outflow channels (and therefore the stress concentrations due to holes in the premix gas burner deck plate) is likely to contribute to a longer life span of the premix gas burner deck plate from a fatigue point of view. In addition, tests carried out by the applicant seem to suggest that the Young's modulus for compression (sometimes also referred to in the art as compression modulus or elasticity modulus for compression) of cast aluminium (e.g. pressure die cast aluminium or sand cast aluminium) is significantly lower than the Young's modulus for tension, even as much as 1.5 — 2 times lower, up to 3 times lower. As a result of this, the compression stresses in the gas discharge area can be expected to be relatively low. This also contributes to a longer life span of the premix gas burner deck plate from a fatigue point of view.
Optionally, in this embodiment, the plate rim area of the premix gas burner deck plate is in thermal contact with a heat sink. The heat sink can be a dedicated heat sink element, or a part of e.g. a body of the premix gas burner, a gas distribution chamber of the premix gas burner or the like may function as a heat sink for the plate rim area. The thermal contact between the plate rim area and the heat sink may be either direct or indirect.
In an embodiment of the premix gas burner in accordance with the invention, the heat transfer area or heat transfer areas of the premix gas burner deck plate is in thermal contact with a heat sink. The heat sink can be a dedicated heat sink element, or a part of e.g. a body of the premix gas burner, a gas distribution chamber of the premix gas burner or the like may function as a heat sink for the heat transfer area or heat transfer areas. The thermal contact between the heat transfer area or heat transfer areas and the heat sink may be either direct or indirect.
In an embodiment of the premix gas burner in accordance with the invention, the premix gas burner comprises a mounting flange which allows to mount the premix gas burner to a heat exchanger, which mounting flange is designed to allow heat transfer from the premix gas burner to the heat exchanger.
Preferably, the premix gas burner is mountable to the heat exchanger in a floating manner.
The invention further pertains to a heating appliance, which is for example a heater system for a building or a domestic hot water system.
The heating appliance according to the invention comprises the premix gas burner according to the invention and a heat exchanger.
Optionally, the premix gas burner deck plate of the premix gas burner is in thermal contact with the heat exchanger.
Optionally, the premix gas burner and the heat exchanger are made of the same material.
Optionally, the premix gas burner and the heat exchanger are integral with each other, e.g. in the form of an integrally cast aluminium element.
The invention further pertains to a method for manufacturing a premix gas burner deck plate according to the invention, which method comprises: - pressure die casting the premix gas burner deck plate in a die, wherein the gas passage area and/or the gas outflow channel are formed in the die.
In case the premix gas burner deck plate comprises a plurality of gas passage areas, optionally multiple gas passage areas are formed in the die. Optionally, in that case, all gas passage areas are formed in the die.
In case the premix gas burner deck plate comprises a plurality of gas outflow channels, optionally multiple gas outflow channels are formed in the die. Optionally, in that case, all gas outflow channels are formed in the die.
The premix gas burner deck plate according to the invention is suitable for pressure die casting, e.g. for high pressure die casting. This allows high production speeds and low manufacturing costs.
Optionally, the method further comprises the step of machining the premix gas burner deck plate to the desired shape and/or required manufacturing tolerances and/or required surface roughness.
As an alternative for pressure die casting, sand casting can be used.
Advantageously, the gas passage area(s) and the gas outflow channel(s) are both formed in the die, as this reduces the number of post-casting machining actions.
In an embodiment of the method for manufacturing a premix gas burner deck plate in accordance with the invention, a tapered gas outflow channel is formed in the die during the pressure die casting.
In case the premix gas burner deck plate comprises a plurality of gas outflow channels, optionally multiple gas flow channels are tapered gas outflow channels and are formed in the die during the pressure die casting. Optionally, in that case, all gas outflow channels are tapered and are formed in the die.
Optionally, the taper angle of a tapered gas outflow channel is optionally at least 6°, for example at least 9°, optionally at least 12°.
An advantage of this embodiment is that it contributes to easy removal of the premix gas burner deck plate from a die when the premix gas burner deck plate is made by pressure die casting and the tapered gas outflow channels are formed in the pressure die casting process.
Optionally, in a variant of this embodiment, the method further comprises the step of: - after the pressure die casting, tuning a local diameter of a gas outflow channel by removing material from the premix gas burner deck plate adjacent to the tapered gas outflow channel.
The material can for example be removed by machining.
Due to the tapered shape of the gas outflow channel(s), by removing a small amount of material adjacent to the tapered gas outflow channel, the diameter of the opening of the gas outflow channel in the outer surface of the gas passage are increases somewhat. In particular the smallest opening of the tapered gas outflow channel determines the pressure drop over the gas outflow channel, which is an important parameter in the design of the premix gas burner deck plate. So, by removing more or less material adjacent to the tapered gas outflow channel, in particular on the side of the opening with the smallest diameter, the pressure drop over the tapered gas outflow channel can be finetuned.
In an embodiment of the method for manufacturing a premix gas burner deck plate in accordance with the invention, the method further comprises the step of: - after the pressure die casting, applying a coating to at least a part of the premix gas burner deck plate, wherein optionally the coating is applied at least on a part of the combustion zone side of the premix gas burner deck plate and/or on an inner wall of the gas outflow channel.
For example, a coating is used which provides protection against sulphur induced corrosion. Sulphur containing substances are sometimes added to fuel gas as odorants, but they may cause corrosion of metals, in particular when they are combusted with oxygen, and react with water H2SO, is formed, which can be highly corrosive.
Optionally, a surface roughness is provided on the premix gas burner deck plate prior to applying the coating, e.g. during the pressure die casting process or sand casting process in which the premix gas burner deck plate is formed.
The invention will be described in more detail below under reference to the drawing, in which in a non-limiting manner exemplary embodiments of the invention will be shown. The drawing shows in:
Fig. 1: schematically, a first embodiment of a premix gas burner deck plate according to the invention,
Fig. 2: schematically, a cross section of the premix gas burner deck plate according to fig. 1, along line A-A of fig. 1,
Fig. 3: schematically, a second embodiment of a premix gas burner deck plate according to the invention,
Fig. 4: schematically, a cross section of the premix gas burner deck plate according to fig. 3, along line A-A of fig. 3,
Fig. 5: schematically, an example of a design of a gas passage area as can be used in a premix gas burner deck plate according to the invention,
Fig. 6: schematically, a first embodiment of a premix gas burner according to the invention.
Fig. 1 shows, schematically, a first embodiment of a premix gas burner deck plate 1 according to the invention. Fig. 2 shows, schematically, a cross section of the premix gas burner deck plate 1 according to fig. 1, along line A-A of fig. 1.
The premix gas burner deck plate of fig. 1 and fig. 2 has a distribution chamber side 2 and a combustion zone side 3. The distribution chamber side 2 and combustion zone side 3 are located on opposite sides of the premix gas burner deck plate 1. When the premix gas burner deck plate 1 is arranged in a premix gas burner, the distribution chamber side 2 of the premix gas burner deck plate 1 faces towards a gas distribution chamber of the premix gas burner, so, in upstream direction of the flow of the premix gas. When the premix gas burner deck plate 1 is arranged in a premix gas burner, the combustion zone side 3 of the premix gas burner deck plate faces towards a combustion zone in which the actual combustion of the premix gas takes place, so, in downstream direction of the flow of the premix gas.
The premix gas burner deck plate according to fig. 1 and fig. 2 comprises a plurality of gas passage areas 10 and a heat transfer area 5. All the recesses shown in fig. 1 are gas passage areas 10. Premix gas passes from the distribution chamber side 2 of the premix gas burner deck plate 1 to the combustion zone side 3 of the premix gas burner deck plate 1 via the gas passage areas 10. The heat transfer area 5 is designed for effective heat transfer, with the aim of avoiding high burner deck temperatures in the premix gas burner deck plate 1during use.
The premix gas burner deck plate 1 has a first plate thickness 11 in the gas passage area and a second plate thickness 6 in the heat transfer area 5. The second plate thickness 6 is larger than the first plate thickness 11. For example, the first plate thickness is 0.5 millimeters (mm) up to and including 1.5 millimeters (mm), for example 1 millimeter (mm). For example, the second plate thickness is 1.5 millimeters (mm) to 10 millimeters (mm), e.g. 2 mmilimeters (mm) up to and including 7 millimeters (mm), for example 2.5 millimeters (mm) to 6 milolimeters (mm) 5 millimeters (mm), e.g. 5 millimeters (mm) or 3 millimeters (mm). Of course, in case the first thickness is 1.5 mm, the second thickness is more than 1.5 mm. For example, the first thickness is 1 mm and the second thickness is 3 mm.
In the embodiment of fig.1 and fig. 2, the premix gas burner deck plate 1 comprises a plurality of gas outflow channels 12, each of which is adapted to during use supply premix gas to the combustion zone, in which combustion zone the combustion of the premix gas takes place during use of the premix gas burner deck plate 1 in a premix gas burner. The combustion zone is usually present adjacent to but just outside of the premix gas burner in which the premix gas burner deck plate is arranged. The gas outflow channels 12 are arranged in the gas passage area 10 and extend through the first plate thickness 11 from the distribution chamber side 2 of the premix gas burner deck plate 1 to the combustion zone side 3 of the premix gas burner deck plate 1.
In the embodiment of fig.1 and fig. 2, each gas passage area 10 comprises a plurality of gas outflow channels 12. The gas outflow channels 12 in each gas passage area 10 are arranged in a predetermined pattern that allows for or is even optimised for the combustion of a premix gas in which the fuel gas is or contains hydrogen
For example, the gas outflow channels 12 all have a circular cross-sectional shape, with a diameter that is either constant or varies over the length of the gas outflow channel 12. In case the diameter varies over the length of the gas outflow channel 12, the gas outflow channel 12 is for example tapered. The taper angle of the gas outflow channel is optionally at least 6°, for example at least 9°, optionally at least 12°. The diameter at an end of the gas outflow channel 12, e.g. at the end with the smallest diameter, is for example 0.6 mm — 1.0 mm, e.g. 0.8 mm. In case the diameter is constant over the length of the gas outflow channel 12, the diameter at an end of the gas outflow channel 12 is for example 0.6 mm — 1.0 mm, e.g. 0.8 mm.
In the embodiment of fig.1 and fig. 2, the premix gas burner deck plate 1 is made of cast aluminium, e.g. pressure die cast aluminium (including high pressure die cast aluminium) or sand cast aluminium. Cast aluminium has a high thermal conductivity, which makes that it is effective in transferring heat away from the premix gas burner deck plate.
Examples of (aluminium) materials that are suitable for use in the premix burner deck plate 1 according to the embodiment of fig.1 and fig. 2, are EN-AC44300 (EN AC-AISi12(Fe),
Werkstoff no. 3.2582), EN-AC 42100 (EN AC Si7Mg0.3, Werkstoff no. 3.2371, LM25), EN-
AC43000 (EN AC-AL Si10Mg(a), Werkstoff no. 3.2381).
In the embodiment of fig. 1 and fig. 2, the combustion zone side of the premix gas burner deck plate 1 is planar. So, in this embodiment, the combustion zone side 3 of the premix gas burner deck plate 1 is devoid of protrusions and indents.
In the embodiment of fig. 1 and fig. 2, optionally at least the heat transfer area 5 and the gas passage areas 10 of the premix gas burner deck plate 1 are manufactured by a pressure die casting process, for example a high pressure die casting process.
The premix gas burner deck plate 1 is then generally formed in a pressure die casting process. For example, different material thicknesses are provided for the gas passage areas 10 and the heat transfer area 5. Optionally, the pressure die cast premix gas burner deck plate 1 is machined after pressure die casting in order to make sure the required manufacturing tolerances are met, but in this embodiment the general shape of the premix gas burner deck plate is obtained by pressure die casting.
Optionally, also the gas outflow channels 12 of the premix gas burner deck plate 1 are formed in the pressure die casting process.
Optionally, in the embodiment of fig.1 and fig. 2, the premix gas burner deck plate 1 is at least partly provided with a coating, e.g. an anti-corrosion coating. For example, a coating is used which provides protection against sulphur induced corrosion. Optionally, a surface roughness is provided on the premix gas burner deck plate prior to applying the coating, e.g. during the pressure die casting process.
As can be seen in fig. 2, in this embodiment, each of the gas outflow channels has a longitudinal axis and the longitudinal axes of all gas outflow channels 12 are parallel to each other.
In the embodiment of fig. 1 and fig. 2, optionally all gas outflow channels 12 each have an inner wall and the gas passage area 10 has an outer surface at the distribution chamber side of the premix gas burner deck plate, and the inner wall of each gas outflow channel 12 meets the outer surface of the gas passage area 10 at the distribution chamber side of the premix gas burner deck plate 1 via a rounded edge.
Fig. 3 shows, schematically, a second embodiment of a premix gas burner deck plate 1 according to the invention. Fig. 4 shows, schematically, a cross section of the premix gas burner deck plate 1 according to fig. 3, along line A-A of fig. 3.
The embodiment of fig. 3 and fig. 4 is similar to the first embodiment as shown in fig. 1 and fig. 2, but has some additional features.
Like in the embodiment of fig.1 and fig. 2, the premix gas burner deck plate of fig. 3 and fig. 4 has a distribution chamber side 2 and a combustion zone side 3. The distribution chamber side 2 and combustion zone side 3 are located on opposite sides of the premix gas burner deck plate 1. When the premix gas burner deck plate 1 is arranged in a premix gas burner, the distribution chamber side 2 of the premix gas burner deck plate 1 faces towards a gas distribution chamber of the premix gas burner, so, in upstream direction of the flow of the premix gas. When the premix gas burner deck plate 1 is arranged in a premix gas burner, the combustion zone side 3 of the premix gas burner deck plate faces towards a combustion zone in which the actual combustion of the premix gas takes place, so, in downstream direction of the flow of the premix gas.
The premix gas burner deck plate according to fig. 3 and fig. 4 comprises a plurality of gas passage areas 10 and a heat transfer area 5. All the recesses shown in fig. 3 are gas passage areas 10. Premix gas passes from the distribution chamber side 2 of the premix gas burner deck plate 1 to the combustion zone side 3 of the premix gas burner deck plate 1 via the gas passage areas 10. The heat transfer area 5 is designed for effective heat transfer, with the aim of avoiding high burner deck temperatures in the premix gas burner deck plate 1during use.
The premix gas burner deck plate 1 has a first plate thickness 11 in the gas passage area and a second plate thickness 6 in the heat transfer area 5. The second plate thickness 6 is larger than the first plate thickness 11.
In the embodiment of fig.3 and fig. 4, the premix gas burner deck plate 1 comprises a plurality of gas outflow channels 12, each of which is adapted to during use supply premix gas to the combustion zone, in which combustion zone the combustion of the premix gas takes place during use of the premix gas burner deck plate 1 in a premix gas burner. The combustion zone is usually present adjacent to but just outside of the premix gas burner in which the premix gas burner deck plate is arranged. The gas outflow channels 12 are arranged in the gas passage area 10 and extend through the first plate thickness 11 from the distribution chamber side 2 of the premix gas burner deck plate 1 to the combustion zone side 3 of the premix gas burner deck plate 1.
In the embodiment of fig.3 and fig. 4 each gas passage area 10 comprises a plurality of gas outflow channels 12. The gas outflow channels 12 in each gas passage area 10 are arranged in a predetermined pattern that allows for or is even optimised for the combustion of a premix gas in which the fuel gas is or contains hydrogen
For example, the gas outflow channels 12 all have a circular cross-sectional shape, with a diameter that is either constant or varies over the length of the gas outflow channel 12. In case the diameter varies over the length of the gas outflow channel 12, the gas outflow channel 12 is for example tapered. The taper angle of the gas outflow channel is optionally at least 6°, for example at least 9°, optionally at least 12°. The diameter at an end of the gas outflow channel 12, e.g. at the end with the smallest diameter, is for example 0.6 mm — 1.0 mm, e.g. 0.8 mm. In case the diameter is constant over the length of the gas outflow channel 12, the diameter at an end of the gas outflow channel 12 is for example 0.6 mm — 1.0 mm, e.g. 0.8mm.
In the embodiment of fig. 3 and fig. 4, the premix gas burner deck plate 1 is made of cast aluminium, e.g. pressure die cast aluminium (including high pressure die cast aluminium) or sand cast aluminium.
In the embodiment of fig. 3 and 4, all gas passage areas 12 are arranged in a central gas discharge zone 13, which is arranged at a distance from a circumferential edge 7 of the premix gas burner deck plate 1, in this case in the center of the premix gas burner deck plate
In the embodiment of fig. 3 and 4, the premix gas burner deck plate 1 comprises a plate rim area 15 adjacent to at least a part of the circumferential edge 7. In this embodiment the premix gas burner deck plate 1 has a third plate thickness 16 in the plate rim area 15, which third plate thickness 16 is larger than the first plate thickness 11, and in this embodiment also larger than the second plate thickness 6.
In the embodiment of fig. 3 and fig. 4, the plate rim area 15 extends along the entire circumference of the premix gas burner deck plate. The gas passage areas 10 are arranged inthe central gas discharge zone 13 and are surrounded by the plate rim area 15.
In the embodiment of fig. 3 and fig. 4, a passage rim area 17 is provided around each of the gas passage areas 10, and the premix gas burner deck plate has a fourth plate thickness in the passage rim area 17. The fourth plate thickness is larger than the first plate thickness 11, and in the embodiment of fig. 3 and fig. 4, also larger than the second plate thickness 8.
In the embodiment of fig. 3 and fig. 4, the fourth plate thickness is equal to the third plate thickness 16.
In the embodiment of fig. 3 and fig. 4, the combustion zone side of the premix gas burner deck plate 1 is planar. So, in this embodiment, the combustion zone side 3 of the premix gas burner deck plate 1 is devoid of protrusions and indents.
In the embodiment of fig. 3 and fig. 4, optionally at least the heat transfer area 5 and the gas passage areas 10 of the premix gas burner deck plate 1 are manufactured by a pressure die casting process, for example a high pressure die casting process.
The premix gas burner deck plate 1 is then generally formed in a pressure die casting process. For example, different material thicknesses are provided for the gas passage areas 10 and the heat transfer area 5. Optionally, the pressure die cast premix gas burner deck plate 1 is machined after pressure die casting in order to make sure the required manufacturing tolerances are met, but in this embodiment the general shape of the premix gas burner deck plate is obtained by pressure die casting.
Optionally, also the gas outflow channels 12 of the premix gas burner deck plate 1 are formed in the pressure die casting process.
Optionally, in the embodiment of fig.3 and fig. 4, the premix gas burner deck plate 1 is at least partly provided with a coating, e.g. an anti-corrosion coating. For example, a coating is used which provides protection against sulphur induced corrosion. Optionally, a surface roughness is provided on the premix gas burner deck plate prior to applying the coating, e.g. during the pressure die casting process.
In the embodiment of fig. 3 and fig. 4, each of the gas outflow channels 12 has a longitudinal axis and, the longitudinal axes of all gas outflow channels 12 are parallel to each other.
In the embodiment of fig. 3 and fig. 4, optionally all gas outflow channels 12 each have an inner wall and the gas passage area 10 has an outer surface at the distribution chamber side of the premix gas burner deck plate, and the inner wall of each gas outflow channel 12 meets the outer surface of the gas passage area 10 at the distribution chamber side of the premix gas burner deck plate 1 via a rounded edge.
Fig. 5 shows, schematically, an example of a design of a gas passage area 10 as can be used in a premix gas burner deck plate 1 according to the invention, e.g. in the first embodiment of fig. 1 and fig. 2 or in the second embodiment of fig. 3 and fig. 4.
In the example of fig. 5, the gas passage 10 comprises multiple gas outflow channels 12 which are arranged in a predefined pattern.
In the example of fig. 5, the gas outflow channels 12 all have a circular cross-sectional shape, with a diameter that varies over the length of the gas outflow channel 12. In this example, the gas outflow channel 12 is tapered. The taper angle of the gas outflow channel is optionally at least 6°, for example at least 9°, optionally at least 12°. The diameter at an end of the gas outflow channel 12, e.g. at the end with the smallest diameter, is for example 0.6 mm — 1.0 mm, e.g. 0.8 mm.
Optionally, the gas passage area 10 of fig. 5 is part of a premix gas burner deck plate which is manufactured by the method according to the invention, and the gas outflow channels 12 are all formed during the pressure die casting process.
Optionally, in the manufacturing method after the pressure die casting, the local diameter of the gas outflow channels 12 at the distribution chamber side and/or of the combustion chamber side of the premix gas burner deck plate 1 is tuned by removing material from the premix gas burner deck plate adjacent to the tapered gas outflow channel, as is for example indicated by lines a and b in fig. 5. Lines a and b in fig. 5 relate to removal of the material from the combustion zone side. The material can for example be removed by machining.
Due to the tapered shape of the gas outflow channels 12, by removing a small amount of material adjacent to the tapered gas outflow channel 12, the diameter of the opening of the gas outflow channel in the outer surface of the gas passage is increased somewhat. This way, the pressure drop over the gas outflow channels 12 can be finetuned, in particular if material is removed from the end of the gas outflow channel that has the smallest diameter.
In the example of fig. 5, this is on the combustion zone side of the premix gas burner deck plate.
Fig. 6 shows, schematically, a first embodiment of a premix gas burner 20 according to the invention. This premix gas burner 20 comprises a premix gas burner deck plate 1 according to the invention, for example a premix gas burner deck plate according to fig. 1 and fig. 2 or according to fig. 3 and fig. 4.
In the embodiment of fig. 6, the premix gas burner 20 comprises a gas distribution chamber 21, which gas distribution chamber 21 is at least partly delimited by the premix gas burner deck plate 1.
In the embodiment of fig. 6, the premix gas burner 20 further comprises a premix gas supply 23 which is adapted to supply premix gas to the gas distribution chamber 21.
From the gas distribution chamber, the premix gas flows through the gas outflow channel(s) of the premix gas burner deck plate to the combustion zone, where the combustion of the premix gas takes place. The arrows in fig. 6 indicate the direction of the gas flow through the premix gas burner 20.
Optionally, a gas distributor 22 is arranged in the gas distribution chamber 21, in order to equally distribute the premix gas over multiple gas outflow channels of the premix gas burner deck plate.
Claims (23)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL2033134A NL2033134B1 (en) | 2022-09-26 | 2022-09-26 | Premix gas burner deck plate |
PCT/EP2023/076317 WO2024068496A1 (en) | 2022-09-26 | 2023-09-25 | Premix gas burner deck plate |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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NL2033134A NL2033134B1 (en) | 2022-09-26 | 2022-09-26 | Premix gas burner deck plate |
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NL2033134B1 true NL2033134B1 (en) | 2024-04-03 |
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NL2033134A NL2033134B1 (en) | 2022-09-26 | 2022-09-26 | Premix gas burner deck plate |
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04158109A (en) * | 1990-10-19 | 1992-06-01 | Paloma Ind Ltd | High load burner of totally primary type |
US20030138749A1 (en) * | 1999-12-11 | 2003-07-24 | Callum Clifford | Burner plaque |
WO2015020525A2 (en) * | 2013-08-09 | 2015-02-12 | Intell Properties B.V. | Gas burner and burner cover |
-
2022
- 2022-09-26 NL NL2033134A patent/NL2033134B1/en active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04158109A (en) * | 1990-10-19 | 1992-06-01 | Paloma Ind Ltd | High load burner of totally primary type |
US20030138749A1 (en) * | 1999-12-11 | 2003-07-24 | Callum Clifford | Burner plaque |
WO2015020525A2 (en) * | 2013-08-09 | 2015-02-12 | Intell Properties B.V. | Gas burner and burner cover |
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