EP3508788A1

EP3508788A1 - Mixer device for a gas burner

Info

Publication number: EP3508788A1
Application number: EP18382003.4A
Authority: EP
Inventors: Mikel OCAÑA SOLA; Aimar ARIN GUTIERREZ
Original assignee: Orkli SCL
Current assignee: Orkli SCL
Priority date: 2018-01-09
Filing date: 2018-01-09
Publication date: 2019-07-10
Anticipated expiration: 2038-01-09
Also published as: KR200497783Y1; WO2019138146A1; EP3508788B1; KR20200001980U; CN212930063U

Abstract

A mixer device (1) comprising a main body (1a) with a comburent gas inlet conduit (2), a combustible gas inlet conduit (3) and a main channel (4) communicated with both inlet conduits (2, 3). The main body (1a) also comprises an auxiliary channel, communicated with the comburent gas inlet conduit (2), and an additional distribution channel, communicated with the combustible gas inlet conduit (3), both channels being blocked by a membrane (6) when it is in a standby position, and allowing the passage of the comburent gas and combustible gas through the corresponding channels when said membrane (6) is moved by the action of the comburent gas flow upon exceeding a specific threshold.

Description

TECHNICAL FIELD

The present invention relates to premix gas burners and to mixing devices of said burners.

PRIOR ART

The combustible gas used in gas burners is generally natural gas, butane or propane. Said combustible gas is mixed with a comburent gas, generally air, and the flame is ignited by means of a spark.
Premix gas burners are fed by a homogeneous mixture of a comburent gas and a combustible gas. This mixing occurs upstream of the means generating the spark required to ignite the flame.
Burners of this type usually comprise a mixing chamber or device in which said comburent gas and said combustible gas are mixed before being conducted to the point of exit, i.e., to the ignition point where the flame is produced.
In mixing devices of burners of this type, the combustible gas is suctioned by the comburent gas due to the Venturi effect and these two gases are mixed due to the generated turbulences.
US20110139045A1 describes a premix gas burner comprising a mixer device. Said mixer device comprises a main body comprising an inlet conduit for air (comburent gas) and an inlet conduit for a combustible gas. The main body comprises a main channel, arranged after the comburent gas inlet conduit, which is divided into two channels in a constricted area. Each channel is communicated with the combustible gas inlet conduit through a combustible gas distribution channel; the combustible gas is therefore suctioned and mixed with the air passing through said constricted area in both channels. One of the channels comprises an opening and closing element for regulating the mixture flow rate.

DISCLOSURE OF THE INVENTION

The object of the invention is to provide a mixer device for a gas burner, as defined in the claims.
The mixer device of the invention comprises a main body comprising a comburent gas, preferably air, inlet conduit, and a combustible gas inlet conduit. The main body also comprises a main channel which is communicated with the comburent gas inlet conduit such that narrowing of the comburent gas flow occurs as the flow is forced to circulate through said main channel. The main channel is communicated with the combustible gas inlet conduit through a combustible gas distribution channel, propitiating the mixing of the combustible gas and comburent gas in said main channel.
The main body also comprises an auxiliary channel communicated with the comburent gas inlet conduit, said auxiliary channel being arranged on the contour of the main channel, and an additional distribution channel communicated with the combustible gas inlet conduit, said additional distribution channel being arranged close to the auxiliary channel.
The mixer device also comprises a flexible membrane which is fixed to the main body and which, in a standby position, is supported on the auxiliary channel and the additional distribution channel blocking both channels. The membrane is configured for being moved by the action of the comburent gas flow arriving through the comburent gas inlet conduit when said flow exceeds a specific threshold, allowing the passage of comburent gas through the auxiliary channel and the passage of combustible gas through the additional distribution channel.
The flow rate of the comburent gas and combustible gas mixture of the gas burner of the invention can be regulated with the mixer device of the invention to vary the burner power in a simple, reliable and cost-effective manner. Likewise, as a result of the membrane, the opening of the auxiliary channel to allow the passage of the comburent gas, and of the additional distribution channel to allow the passage of combustible gas, is gradual, which allows an also gradual variation of the pneumatic signal controlling the valve which manages the passage of the combustible gas to the distribution channel and the additional combustible gas distribution channel. Therefore, the regulation of the amount of combustible gas required to assure a homogeneous mixture based on the input amount of comburent gas is performed in an accurate and precise manner, so the CO₂ emission curve remains constant over the entire range of modulation (regulation), where the peaks that would be generated in the event of a sudden opening of rigid opening and closing means are prevented.
Likewise, by not having dynamic mechanical elements, the mixer device is more robust and reliable, since it does not require any maintenance whatsoever.
These and other advantages and features of the invention will become evident in view of the drawings and the detailed description of the invention.

DESCRIPTION OF THE DRAWINGS

Figure 1 shows a perspective view of the mixer device according to an embodiment of the invention.
Figure 2 shows a plan view of the mixer device of Figure 1.
Figure 3 shows another perspective view of the mixer device of Figure 1 but with a portion having been cut away.
Figure 4 shows a cut-away view of the mixer device of Figure 1.
Figure 5 shows the membrane of the mixer device of Figure 1.
Figure 6 shows a detail of the mixer device of Figure 1.
Figure 7 shows a second embodiment of the membrane of the mixer device according to the invention.
Figure 8A shows a third embodiment of the membrane of the mixer device according to the invention.
Figure 8B shows the rear view of the membrane of Figure 8A.
Figure 9 shows a fourth embodiment of the membrane of the mixer device according to the invention.

DETAILED DISCLOSURE OF THE INVENTION

Figure 1 shows the mixer device 1 according to a preferred embodiment of the invention. As shown in said drawing, the mixer device 1 comprises a main body 1a comprising an inlet conduit 2 for a comburent gas, preferably air, and an inlet conduit 3 for a combustible gas. The main body 1a also comprises a main channel 4 which is communicated with the comburent gas inlet conduit 2 such that narrowing of the comburent gas flow occurs as the flow is forced to circulate through said main channel 4. The main channel 4 is communicated with the combustible gas inlet conduit 3, as shown in Figure 3, through a combustible gas distribution channel 3.1, propitiating the mixing of the combustible gas and comburent gas in said main channel 4. In the embodiment of the invention, said main channel 4 is preferably circular, as shown in the drawings, but other shapes are not ruled out.
The main body 1a also comprises an auxiliary channel 5 communicated with the comburent gas inlet conduit 2, said auxiliary channel 5 being arranged on the contour of the main channel 4, and an additional distribution channel 3.2 communicated with the combustible gas inlet conduit 3, said additional distribution channel 3.2 being arranged close to the auxiliary channel 5.
The mixer device 1 also comprises a flexible membrane 6, at least a portion of said membrane 6 being fixed to the main body 1a, which in a standby position is supported on the auxiliary channel 5 and the additional distribution channel 3.2, blocking both channels 5 and 3.2. The membrane 6 is configured for being moved by the action of the comburent gas flow arriving through the comburent gas inlet conduit 2 when said flow exceeds a specific threshold value, allowing the passage of comburent gas through the auxiliary channel 5 and the passage of combustible gas through the additional distribution channel 3.2. The opening of the membrane 6, after the comburent gas flow exceeds said threshold value, occurs gradually.
The flow rate of the comburent gas and combustible gas mixture can be regulated with the mixer device 1a of the invention in a simple, reliable and cost-effective manner. Therefore, the regulation of the power of the burner of the invention is also performed in a safe and reliable manner, where a power regulation or modulation of at least 1 to 10 may be achieved. Likewise, as a result of the membrane 6, the opening of the auxiliary channel 5 to allow the passage of the comburent gas, and of the additional distribution channel 3.2 to allow the passage of combustible gas, is gradual, which allows an also gradual variation of the pneumatic signal controlling a valve which manages the passage of combustible gas to the distribution channel 3.1 and the additional combustible gas distribution channel 3.2. Said pneumatic signal is the differential pressure between the pressure of the comburent gas flow at the inlet of the inlet conduit 2 and the comburent gas flow, for example, at the height where it runs into the combustible gas in the main channel 4 and/or the additional distribution channel 3.2. As the membrane 6 gradually opens, the constricted area of the mixer device 1 caused by the main channel 4 and by the additional distribution channel 3.2 becomes smaller as the comburent gas flow increases (since the total section of passage of the comburent gas increases), and the combustible gas, and therefore the burner power also gradually increases.
The flexible membrane 6 of the invention is an element having a small thickness, as one skilled in the art knows, which is effective even in the event of small variations in the comburent gas flow rate, and therefore allows maintaining the pneumatic signal so as to be sufficient for effectively and gradually controlling said valve.
Therefore, the regulation of the amount of combustible gas required to assure a homogeneous mixture based on the input amount of comburent gas is performed in an accurate and precise manner, so the CO₂ emission curve remains constant over the entire range of modulation (regulation), where the peaks that would be generated in the event of a sudden opening of rigid opening and closing means are prevented.
Likewise, by not having dynamic mechanical elements, the mixer device 1a is more robust and reliable, since it does not require any maintenance whatsoever. Furthermore, its manufacture and assembly are much simpler mainly due to the absence of mechanical parts.
The main body 1a according to the preferred embodiment of the invention comprises a main opening 10, preferably arranged centered with respect to the axial axis of the main body 1a, and a main tube 9 arranged in said main opening 10. The main tube 9 comprises therein the main channel 4, as seen in the drawings (see, for example, Figure 3 or 4), propitiating a constriction which favors the Venturi effect when the comburent gas from the inlet conduit 2 is forced to go through said main channel 4 with a smaller section.
Additionally, the main opening 10 comprises the auxiliary channel 5, as seen in the drawings (see, for example, Figure 2 or 3), propitiating also a constriction which favors the Venturi effect when the comburent gas from the inlet conduit 2 is forced to go through said auxiliary channel 5 with a smaller section if it is open, i.e., if it is not blocked by the membrane 6.
The membrane 6, when it is open, i.e., when it does not block the auxiliary channel 5 and the additional distribution channel 3.2, breaks the laminar flow of the comburent gas entering the auxiliary channel 5, causing a turbulent regime which improves the effectiveness of the comburent /combustible gas mixture, improving performance with respect to gas burner CO₂ emissions.
The main body 1a according to the preferred embodiment of the invention comprises a perimetral groove 11 arranged close to the main opening 10, as seen in Figures 3 and 4, the additional distribution channel 3.2 comprising said perimetral groove 11. As seen in said Figures 3 and 4, the perimetral groove 11 surrounds the auxiliary channel 5, said perimetral groove 11 and said auxiliary channel 5 being separated by a separating wall 8, the main opening 10 being contained inside said separating wall 8.
As seen in Figure 2, in the preferred embodiment of the invention the perimetral groove 11, the main opening 10 and the main tube 9 are coaxial.
The main body 1a according to the preferred embodiment of the invention comprises at least one support arm 12.1 joining the main tube 9 to the contour of the main opening 10, the combustible gas distribution channel 3.1 reaching the main channel 4 of the main tube 9 through one of said support arms 12.1, as shown in Figures 3 and 4.
As seen in Figure 4, the distribution channel 3.1 is a linear channel having a preferably circular section communicated with the main channel 4 at approximately mid-height of said main channel 4.
As seen in Figures 2, 3 and 4, the main body 1a comprises a second support arm 12.1 aligned with the first support arm 12.1, the main tube 9 being arranged between both support arms 12.1.
The membrane 6 according to the preferred embodiment of the invention comprises a central opening 6.4 to allow the passage of the main tube 9, as shown in Figure 1, the membrane 6 being fixed to said main tube 9 in the preferred embodiment of the invention, as will be described in detail below.
In the preferred embodiment of the invention, the membrane 6 comprises two flanges 6.3, one on each side of the support arms 12.1, said flanges 6.3 being supported on said support arms 12.1 such that each flange 6.3 can be moved, pivoting with respect to the areas fixed to the main body 1a, pushed by the comburent gas flow when said flow exceeds a specific threshold value, opening the passage of the auxiliary channel 5 and the additional distribution channel 3.2. When the comburent gas flow drops below said threshold value, the membrane 6 returns to the standby position, the flanges 6.3 again obstructing the auxiliary channel 5 and the additional distribution channel 3.2. Optionally, the flanges 6.3 can also be fixed to the support arms 12.1.
The comburent gas flow is regulated by gas burner ventilation means.
By default, the gas burner is regulated to work at a low power, i.e., so that the membrane 6 is in the standby position, feeding the head of the burner only with the comburent /combustible gas mixture from the main channel 4. However, if it is desired to add more power to the gas burner, raising the power of the ventilation means will be enough to increase the comburent gas flow. When said flow exceeds the preestablished threshold value, the flanges 6.3 will lift up, opening the auxiliary channel 5 and the additional distribution channel 3.2, thereby increasing the flow of the comburent /combustible gas mixture. The flanges 6.3 will open to a greater or lesser extent depending on the comburent gas flow, i.e., depending on the power of the ventilation means.
Since the opening of the flanges 6.3 of the membrane 6 is gradual, the valve which manages the passage of the combustible gas can also be gradually regulated, as explained above. Therefore, the regulation of the amount of combustible gas required to assure a homogeneous mixture based on the input amount of comburent gas is performed in an accurate and precise manner, so the CO₂ emission curve remains constant over the entire range of modulation (regulation), where the peaks that would be generated in the event of a sudden opening of rigid opening and closing means are prevented.
The comburent gas and combustible gas once mixed go to an outlet conduit 13 comprised in the main body 1a and arranged after the main channel 4, the auxiliary channel 5 and the additional distribution channel 3.2. Said outlet conduit 13 is communicated with a distributor, not shown in the drawings, which helps to distribute and direct said mixture to the head of the burner so that the corresponding flame is produced in the presence of a spark.
The membrane 6 according to the preferred embodiment of the invention also comprises a support face 6.1, arranged on the back of the membrane 6, comprising a planar surface which, in the standby position, rests on the auxiliary channel 5 and the additional distribution channel 3.2 obstructing both channels 5 and 3.2, and an outer face 6.2, arranged on the front of the membrane 6, comprising at least one reinforcement rib 7 projecting from said outer face 6.2, as shown in Figure 1, for example.
In the preferred embodiment of the invention, the support face 6.1 of the membrane 6 rests, in the standby position, on the outer surface of the support arms 12.1, the outer surface of the separating wall 8, and a third support surface 12.3 extending radially from the additional distribution channel 3.2, the membrane 6 preferably being fixed to the main body 1a around the main tube 9 and the support arms 12.1. The outer surfaces of the support arms 12.1 and the separating wall 8 and said third support surface 12.3 are at the same level.
Optionally, the support face 6.1 of the membrane 6 can comprise a perimetral lip, preferably arranged after the planar face to favor sealing of the auxiliary channel 5 and the additional distribution channel 3.2. Said perimetral lip can be supported, for example, on the third support surface 12.3 when the membrane 6 is in the standby position.
The membrane 6 according to the preferred embodiment of the invention comprises a plurality of radial reinforcement ribs 7, as seen in Figure 1. Optionally, the membrane 6 can also comprise at least one diametral reinforcement rib 7', where said reinforcement rib 7' can be divided into several portions.
The reinforcement ribs 7 and 7' prevent the flanges 6.3 from swinging, i.e., from having a back and forth movement, when said flanges 6.3 are moved away from the standby position pushed by the comburent gas flow. The flanges 6.3 are symmetrical, the forces required to move said flanges 6.3 away from the standby position thereby being balanced, so the flanges 6.3 will be moved simultaneously.
Figure 7 shows a second embodiment of the membrane 6. This membrane 6 also comprises two flanges 6.3 and all the features described above, but unlike the membrane 6 of the first embodiment, said flanges 6.3 are contained in a perimetral lip 6.5, said lip 6.5 being supported and additionally fixed on the third support surface 12.3 of the main body 1a. This configuration allows better fixing of the membrane 6 to the main body 1a.
In a third embodiment of the invention, the membrane 6 has a cup shape, as shown in Figures 8A and 8B. The outer circumferential wall 6.6 of said cup and/or the upper lip 6.7 is fixed to the main body 1a, preferably to the inner wall of the outlet conduit 13. The membrane 6 of this embodiment preferably comprises four flanges 6.3 arranged in the base of the cup which are opened and closed from the main tube 9, depending on the comburent gas flow arriving through the inlet conduit 2, as explained above.
In a non-limiting example, the partition of these four flanges 6.3 form a cross, said cross preferably being arranged such that it does not coincide with the support arms 12.1 of the main body 1a, i.e., such that none of the sides of the cross coincides or is aligned with the support arms 12.1.
Optionally, the cup-shaped membrane 6 can comprise a diametral reinforcement rib 7' arranged close to the main tube 9, i.e., close to the edge of the central opening 6.4 of the membrane 6 itself, which is divided into several portions, preferably one for each flange 6.3, as seen in Figure 9, showing a fourth embodiment of the membrane 6. This rib 7', like the radial ribs 7 and/or diametral ribs 7' of the first embodiment, prevent the flanges 6.3 from swinging when said flanges 6.3 are moved away from the standby position, pushed by the comburent gas flow. Additionally, this membrane 6 can also comprise more diametral reinforcement ribs 7' and/or radial reinforcement ribs 7.
Like in the membranes 6 described above, in this case the flanges 6.3 are also symmetrical such that the forces required to move said flanges 6.3 away from the standby position are also balanced so that the flanges are moved simultaneously.
In the preferred embodiment of the invention, the membrane 6 (according to any of the described embodiments) is fixed to the main body 1a by overmolding, a compact and robust mixer device 1 with a simple and cost-effective design thereby being obtained. The areas of attachment between the membrane 6 and the main body 1a correspond with the fixing areas described for each embodiment.
Optionally, the membrane 6 of the invention can also be fixed to the main body 1a, in the fixing areas described for each embodiment, by ultrasounds, by welding or by means of applying an adhesive.
The membrane 6 and the main body 1a could also be by attached to one another by cold or hot deformation. In this sense, part of the main body 1a may be deformed to retain at least a portion of the membrane 6, once the membrane 6 has been arranged in the final position, retaining at least a portion of the membrane 6. In a non-limiting example, once the membrane 6 has been arranged on the main body 1a in the final position, the main tube of the main body 1a is deformed, retaining the edge of the central opening 6.4 of the membrane 6.
The main tube 9 according to the preferred embodiment of the invention comprises a planar face 15 arranged on at least one side which cooperates with a corresponding planar face of the membrane 6 arranged in the central opening 6.4, as seen in Figure 7, to assure correct placement of the membrane 6 of the invention on the main body 1a of the mixer device 1.
Optionally, the main tube 9 can comprise two planar faces 15 arranged on two opposite sides, each one cooperating with a corresponding planar face 15' of the membrane 6, the two faces being arranged facing one another in the central opening 6.4, to make the assembly thereof easier.
In a preferred embodiment, the membrane 6 of the invention is made of silicone, EPDM or NBR (nitrile butadiene rubber) and the main body 1a of the mixer device 1 is made of a rigid plastic, preferably polyamide, or of metal.
As a result of the mixer device 1 of the invention, the gas burner CO₂ emission curve remains constant over the entire range of modulation, i.e., regulation, where the peaks that would be generated in the event of a sudden opening and closing of the auxiliary channel 5 and of the additional distribution channel 3.2 are prevented. If rigid opening and closing means are used instead of the flexible membrane 6, like in the case of US20110139045A1 , said opening and also closing would be immediate, so in a relatively short period of time the variation of the combustible gas and comburent gas before the opening of the additional distribution channel 3.2 and the auxiliary channel 5, and right after the opening, would be high, giving rise to said unwanted peaks.
The main body 1a of the mixer device 1 comprises fixing means, preferably a plurality of holes 14 arranged diametrically, as seen in Figure 1, for example, to allow attaching the mixer device 1 to the gas burner.
The comburent gas used in the burner and the mixer device 1 of the invention is air and the comburent gas can be natural gas, butane or propane.
The invention also relates to a gas burner comprising the mixer device of the invention.

Claims

A mixer device for a gas burner, comprising a main body (1a) comprising a comburent gas, preferably air, inlet conduit (2), a combustible gas inlet conduit (3), a main channel (4) communicated with the comburent gas inlet conduit (2) such that narrowing of the comburent gas flow occurs as the flow is forced to circulate through said main channel (4), said main channel (4) being communicated with the combustible gas inlet conduit (3) through a combustible gas distribution channel (2.1), propitiating the mixing of the combustible gas and comburent gas in said main channel (4), and an auxiliary channel (5) communicated with the comburent gas inlet conduit (2), said auxiliary channel (5) being arranged close to the main channel (4), characterized in that the main body (1a) also comprises an additional distribution channel (2.2) communicated with the combustible gas inlet conduit (3), said additional distribution channel (2.2) being arranged close to the auxiliary channel (5), the mixer device (1) also comprising a flexible membrane (6) which is fixed to the main body (1a) and which, in a standby position, is supported on the auxiliary channel (5) and the additional distribution channel (2.2) blocking both channels (5, 2.2), the membrane (6) being configured for being moved by the action of the comburent gas flow arriving through the comburent gas inlet conduit (2) when said flow exceeds a specific threshold, allowing the passage of comburent gas through the auxiliary channel (5) and the passage of combustible gas through the additional distribution channel (2.2).
The mixer device according to claim 1, wherein the main body (1a) comprises a main opening (10), preferably central, and a main tube (9) arranged in said main opening (10), the main tube (9) comprising the main channel (4) and the main opening (10) comprising the auxiliary channel (5).
The mixer device according to claim 2, wherein the main body (1a) comprises a perimetral groove (11) close to the main opening (10), the additional distribution channel (2.2) comprising said perimetral groove (11).
The mixer device according to claim 3, wherein the perimetral groove (11), the main opening (10) and the main tube (9) are coaxial.
The mixer device according to any of claims 2 to 4, wherein the main body (1a) comprises at least one support arm (11.3) joining the main tube (9) to the contour of the main opening (10), the combustible gas distribution channel (2.1) reaching the distribution channel (4) of the main tube (9) through one of said support arms (11.3).
The mixer device according to any of claims 2 to 5, wherein the membrane (6) comprises a central opening (6.4) to allow the passage of the main tube (9).
The mixer device according to any of claims 2 to 6, wherein the membrane (6) comprises a support face (6.1) comprising a planar surface which, in the standby position, rests on the auxiliary channel (5) and the additional distribution channel (2.2), and an outer face (6.2) comprising at least one reinforcement rib (7) outwardly-projecting.
The mixer device according to claim 7, wherein the membrane (6) comprises a plurality of radial reinforcement ribs (7) and/or at least one diametral reinforcement rib (7').
The mixer device according to any of claims 2 to 8, wherein the membrane (6) is fixed to at least the main tube (9).
The mixer device according to any of claims 5 to 9, comprising two aligned support arms (11.3), the membrane (6) comprising two flanges (6.3), one on each side of the support arms (11.3), said flanges (6.3) being supported and preferably fixed on said support arms (11.3).
The mixer device according to any of claims 1 to 8, wherein the membrane (6) has a cup shape, the outer wall of said cup being fixed to the main body (1a), and the membrane (6) comprising at least two flanges (6.3), preferably four flanges (6.3), which are opened and closed from the central part of the membrane (6) depending on the comburent gas flow arriving through the inlet conduit (2).
The mixer device according to any of the preceding claims, wherein the membrane (6) is fixed to the main body (1a) by overmolding.
The mixer device according to any of claims 2 to 11, wherein the membrane (6) is fixed to the main body (1a) by cold or hot deformation of at least part of the main tube (9) which retains a portion of the membrane (6), by ultrasounds, by welding or by means of applying an adhesive.
The mixer device according to any of the preceding claims, wherein the membrane (6) is made of silicone, EPDM or NBR and the main body (1a) of the mixer device (1) is made of a rigid plastic, preferably polyamide.
Premix gas burner, characterized in that it comprises a mixer device (1) according to any of the preceding claims.