Liquid or gas fuel burner

Abstract

A liquid or gaseous fuel burner has a supply circuit for supplying a liquid or gaseous fuel to a burner head (2); a first pneumatic circuit (3) configured to supply oxidation air to the combustion head (2) and provided with first valve means (7); and a second pneumatic circuit (4) configured to feed a flow of combustion fumes from the combustion head (2) into the first pneumatic circuit (3) and provided with second valve means (11) movable between a closed position and an open position of the second pneumatic circuit (4) and third valve means (12) movable between a closed position and an open position of the second pneumatic circuit (4). Third valve means are connected to the first valve means (7) to move between a closed position of the second pneumatic circuit (4) and a plurality of open positions for each open position of the first pneumatic circuit (3), and selectively control the emission of nitrogen oxides NOx. The liquid or gas fuel burner provided by the utility model has relatively many operation modes and relatively strong multifunctionality.

Description

TECHNICAL FIELD

[0001] The present utility model relates to a liquid or gaseous fuel burner. BACKGROUND

[0002] In particular, the present utility model relates to a liquid or gaseous fuel burner of the type comprising: a combustion head; a supply circuit for supplying a liquid or gaseous fuel to the combustion head; a first pneumatic circuit for supplying oxidizing air to the combustion head; and a second pneumatic circuit for supplying a combustion fume flow from the combustion head into the first pneumatic circuit.

[0003] The second pneumatic circuit makes it possible to selectively control the oxygen concentration in the mixture of oxidizing air and combustion fumes supplied into the combustion head and thus to ensure a relatively low emission of nitrogen oxides NOx, i.e. polluting agents harmful to human health.

[0004] The first pneumatic circuit comprises: a first supply duct connected to the combustion head; an impeller for supplying an oxidizing air flow along the first supply duct; and at least one shut-off gate movable between a closed position of the first supply duct and at least two open positions.

[0005] The second pneumatic circuit comprises: a second supply duct connected to the first supply duct; and two valve devices successively mounted along the second supply duct to control the supply of combustion fumes to the first supply duct.

[0006] Generally, a valve device comprises a first shut-off member, in particular a first plate, mounted in the second supply duct, and the other valve device comprises a second shut-off member, in particular a second plate, mounted in the second supply duct downstream of the first plate.

[0007] The second pneumatic circuit further comprises: an electric motor for moving the first plate between an open position and a closed position of the second supply duct; and a crank mechanism interposed between the shut-off gate and the second plate to allow the shut-off gate to move the second plate between a closed position and at least two open positions of the second supply duct.

[0008] When at least one of the valve devices is in the relatively closed position of the second supply duct, the combustion head is supplied only with oxidizing air.

[0009] When both valve devices are in the relatively open position of the second supply duct, the combustion head is supplied with a mixture of oxidizing air and combustion fumes to ensure a relatively low emission of nitrogen oxides NOx, i.e. polluting agents harmful to human health.

[0010] Known liquid or gaseous fuel burners of the type described above have some drawbacks, mainly due to the crank mechanism being configured so that each open position of the shut-off shutter corresponds to a single open position of the second shutter.

[0011] Therefore, the crank mechanism causes the second valve device to have a relatively small number of open positions and causes the burner to have a relatively limited operating mode and versatility. SUMMARY

[0012] The object of the present utility model is to provide a liquid or gaseous fuel burner which does not have the above-mentioned drawbacks and which can be manufactured in a simple and economical manner.

[0013] The utility model provides a liquid or gaseous fuel burner, comprising: a combustion head; a supply circuit for supplying liquid or gaseous fuel to the combustion head; a first pneumatic circuit for supplying oxidizing air to the combustion head, the first pneumatic circuit comprising a first supply duct, a first valve device and a first operating device, the first operating device being for moving the first valve device between a closed position and at least two open positions of the first supply duct; and a second pneumatic circuit for supplying a combustion fume stream from the combustion head to the first pneumatic circuit, the second pneumatic circuit comprising: a second supply duct interposed between the combustion head and the first pneumatic circuit; a second valve device and a third valve device, mounted in sequence along the second supply duct in the order of the second valve device first and the third valve device second; a second operating device for moving the second valve device between an open position and a closed position of the second supply duct; and a third operating device interposed between the first valve device and the third valve device to allow the first valve device to control the third valve device to move between the open position and the closed position of the second supply duct; and wherein the third operating device is configured to selectively move the third valve device to a plurality of open positions of the second supply duct for each open position of the first valve device.

[0014] Preferably, the first valve device comprises a first shut-off member mounted inside the first supply duct, and the first operating device comprises a first electric motor to move the first shut-off member between the closed position and the open position of the first supply duct.

[0015] Preferably, the second valve device comprises a second shut-off member mounted inside the second supply duct, and the second operating device comprises a second electric motor to move the second shut-off member between the relatively open position and the relatively closed position of the second supply duct.

[0016] Preferably, the third valve device comprises a third shut-off member mounted inside the second supply duct, and the third operating device comprises a crank mechanism interposed between the first shut-off member and the third shut-off member.

[0017] Preferably, the third shut-off member is mounted for rotation about the first rotation axis, and the lever mechanism comprises a first lever coupled in an angularly fixed manner to the third shut-off member for rotation about the first rotation axis, and a lever member selectively coupled in a rotational manner in the region of a plurality of first fulcrum axes to the first lever, each of the plurality of first fulcrum axes being associated with a respective open position of the third shut-off member.

[0018] Preferably, the first shut-off member comprises two gates mounted for rotation about respective second rotation axes between a closed position and an open position of the first pneumatic circuit, and the lever mechanism comprises, for each gate, a respective second lever coupled in an angularly fixed manner to the gate for rotation about the associated second rotation axis.

[0019] Preferably, the lever mechanism further comprises a connecting lever for interconnecting the second levers, and a connecting rod for interconnecting the connecting lever and the first lever.

[0020] Preferably, the connecting lever is coupled in a rotational manner in the region of a respective second fulcrum axis to the second levers, and the connecting rod is coupled in a rotational manner in the region of a third fulcrum axis to the connecting lever and the connecting rod is selectively coupled in a rotational manner in the region of the first fulcrum axis to the first lever.

[0021] The liquid or gaseous fuel burner according to the present application has a relatively high number of operating modes and a relatively strong versatility. BRIEF DESCRIPTION OF DRAWINGS

[0022] The present application will now be described with reference to the drawings, which show non-limiting embodiments of the present application, in which:

[0023] Figure 1 is a schematic perspective view of a preferred embodiment of the burner according to the present application, in which some parts have been removed for greater clarity;

[0024] Figure 2 is a schematic perspective view of a detail of the burner of Figure 1 , in which some parts have been removed for greater clarity; and

[0025] Figure 3 is a schematic perspective view of a detail of the burner of Figure 2 , in which some parts have been removed for greater clarity. DETAILED DESCRIPTION

[0026] With reference to Figure 1 , Figure 2 and Figure 3, the number 1 as a whole denotes a liquid or gaseous fuel burner comprising: a known combustion head 2; a known feeding circuit (not shown here), for feeding liquid or gaseous fuel to the combustion head 2; a first pneumatic circuit 3, for feeding oxidizing air to the combustion head 2; and a second pneumatic circuit 4, for feeding a flow of combustion fumes from the combustion head 2 into the first pneumatic circuit 3.

[0027] The first pneumatic circuit 3 comprises: a first feeding duct 5, connected to the combustion head 2 and provided with an inlet 6 for oxidizing air; a known impeller (not shown here), housed inside a closed seat downstream of the first feeding duct 5, to feed a flow of oxidizing air to the combustion head 2; and first valve means 7, for selectively controlling the feeding of oxidizing air through the inlet 6 and along the first feeding duct 5.

[0028] The first valve means 7 comprise a pair of first shut-off members 8, mounted in succession inside the inlet 6 and coupled in rotation to the first feeding duct 5, to rotate about respective second rotation axes 9 parallel to each other, between a closed position (not shown) of the inlet 6 and at least two open positions (not shown) of the inlet 6, with respect to the first feeding duct 5 and as a result of the thrust of known and not shown operating means, in particular an electric motor. Figure 3

[0029] The second pneumatic circuit 4 comprises: a second feeding duct 10, interposed between the combustion head 2 and the first feeding duct 5; and second valve means 11 and third valve means 12, mounted in succession along a longitudinal axis 13 of the second feeding duct 10, in the order of the second valve means and then of the third valve means, to selectively control the feeding of combustion fumes along the second feeding duct 10.

[0030] The second valve means 11 comprise a second shut-off member 14, in this particular case defined by a plate with a circular shape, mounted inside the second feeding duct 10 and screwed to an output shaft 15 of second operating means 16, in particular an electric motor, located outside the second feeding duct 10.

[0031] The output shaft 15 is mounted to rotate about a rotation axis 17 transverse to the longitudinal axis 13, the output shaft extending through the second feeding duct 10 and being rotated about the rotation axis 17 by the second operating means 16, to move the second shut-off member 14 between a closed position (not shown) of the second feeding duct 10 and an open position (not shown) of the second feeding duct 10. Figure 3

[0032] The third valve means 12 comprise a third shut-off member 18, in this particular case defined by a plate with a circular shape, mounted inside the second feeding duct 10 and screwed to a support shaft 19 mounted through the second feeding duct 10, to rotate about a first rotation axis 20 parallel to the rotation axis 17.​​

[0033] The third shut-off member 18 is moved between a closed position (not shown) Figure 3 ) and a plurality of open positions (which will be better described below) about the first rotation axis 20 by a third operating device 21 (in particular a transmission assembly) interposed between the first shut-off member 8 and the support shaft 19.

[0034] The third operating device 21 comprises a first crank 22 projecting radially outwards from the support shaft 19 and a lever mechanism 23 interposed between the first shut-off member 8 and the first crank 22.

[0035] For each first shut-off member 8, the lever mechanism 23 comprises a respective second crank 24 extending transversely to the second rotation axis 9 of the first shut-off member 8 and fixed to the first shut-off member 8 for rotation about the second rotation axis 9, and a connecting rod 25 extending between two second fulcrum axes 26, one of which is a rotation axis of the connecting rod 25 with respect to one second crank 24 and the other of which is a rotation axis of the connecting rod 25 with respect to the other second crank 24.

[0036] The lever mechanism 23 further comprises an elongated link 27 extending between a third fulcrum axis 28, which is a rotation axis of the link 27 with respect to the connecting rod 25, and a first fulcrum axis 29, which is a rotation axis of the link 27 with respect to the first crank 22.

[0037] To this end, it should be noted that:

[0038] The first crank 22 is provided with a plurality of coupling holes 30 (in particular five coupling holes 30) obtained through the first crank 22 at different distances from the first rotation axis 20; and

[0039] The link 27 is selectively coupled to the coupling holes 30 in a rotatable and releasable manner for rotation about the plurality of first fulcrum axes 29 with respect to the first crank 22.

[0040] In use:

[0041] When at least one of the second shut-off member 14 and the third shut-off member 18 is in its closed position, the combustion head 2 is fed with oxidizing air along the first feed duct 5 only by the impeller (not shown);

[0042] When both the second shut-off member 14 and the third shut-off member 18 are in their open positions, the combustion head 2 is fed with a mixture of oxidizing air and combustion fumes to ensure a relatively low emission of nitrogen oxides NOx (i.e. polluting agents harmful to human health); and

[0043] The selective coupling of the connecting rod 27 to the coupling holes 30 allows to selectively control the opening position of the third shut-off member 18 for each opening position of the first shut-off member 8.

[0044] In other words, the first shut-off member 8 is movable to a plurality of opening positions due to the thrust of the relative operating means (not shown); in each opening position of the first shut-off member 8, the third shut-off member 18 is movable to a plurality of opening positions (in particular, five opening positions) due to the thrust of the third operating means 21, the number of which is as many as the number of coupling holes 30 obtained by the first crank 22.

[0045] In this particular case, the connecting rod 27 can be selectively coupled to the coupling holes 30 to vary the opening position of the third shut-off member 18 between a minimum angle of 30° and a maximum angle of 90° in each opening position of the first shut-off member 8.

[0046] The burner 1 has some advantages, mainly due to the fact that the third operating means 21 are configured so that each opening position of the first shut-off member 8 corresponds to a plurality of opening positions (in particular, five opening positions) of the third shut-off member 18.

[0047] Therefore, the third operating means 21 allow the third valve device 12 to have a relatively large number of opening positions and allow the burner 1 to have a relatively large number of operating modes and a relatively strong versatility to selectively control the emission of nitrogen oxides NOx.

[0048] This utility model application claims the priority of Italian patent application 102024000020149, filed on September 10, 2024, the entire disclosure of which is incorporated herein by reference.

Claims

1. A liquid or gaseous fuel burner, comprising: Combustion head (2); supply circuit for supplying liquid or gaseous fuel to the combustion head (2); first pneumatic circuit (3) for supplying oxidizing air to the combustion head (2), the first pneumatic circuit (3) including a first supply pipe (5), a first valve device (7) and a first operating device, the first operating device for moving the first valve device (7) between a closed position and at least two open positions of the first supply pipe (5); and a second pneumatic circuit (4) for supplying combustion flue gas from the combustion head (2) to the first pneumatic circuit (3), the second pneumatic circuit (4) including: a second supply pipe (10) between the combustion head (2) and the first pneumatic circuit (3); a second valve device (11) and a third valve device (12). The valve is installed sequentially along the second supply pipe (10) in the order of the second valve device first and the third valve device last; a second operating device (16) for moving the second valve device (11) between an open position and a closed position of the second supply pipe (10); and a third operating device (21) between the first valve device (7) and the third valve device (12) to allow the first valve device (7) to control the third valve device (12) to move between an open position and a closed position of the second supply pipe (10); characterized in that the third operating device (21) is configured to selectively move the third valve device (12) to a plurality of open positions of the second supply pipe (10) for each open position of the first valve device (7).

2. The liquid or gaseous fuel burner according to claim 1, characterized in that, The first valve device (7) includes a first shut-off member (8) installed inside the first supply pipe (5), and the first operating device includes a first motor to move the first shut-off member (8) between a closed position and an open position of the first supply pipe (5).

3. The liquid or gaseous fuel burner according to claim 1 or 2, characterized in that, The second valve device (11) includes a second shut-off member (14) installed inside the second supply pipe (10), and the second operating device (16) includes a second motor to move the second shut-off member (14) between a relatively open position and a relatively closed position of the second supply pipe (10).

4. The liquid or gaseous fuel burner according to claim 2, characterized in that, The third valve device (12) includes a third shut-off member (18) installed inside the second supply pipe (10), and the third operating device (21) includes a crank mechanism between the first shut-off member (8) and the third shut-off member (18).

5. The liquid or gaseous fuel burner according to claim 4, characterized in that, The third stop member (18) is mounted to rotate about a first rotation axis (20), and the crank mechanism includes: a first crank (22) fixed at an angle to the third stop member (18) for rotation about the first rotation axis (20); and a lever mechanism (23) rotatably connected to the first crank (22) in a region of a plurality of first fulcrum axes (29), each of the plurality of first fulcrum axes being associated with a relative open position of the third stop member (18).

6. The liquid or gaseous fuel burner according to claim 5, characterized in that, The first stop member (8) includes two gates mounted to rotate between the closed and open positions of the first pneumatic circuit (3) about a corresponding second rotation axis (9), and the lever mechanism (23) includes a corresponding second crank (24) for each gate, the second crank being fixed at an angle to the gate so as to rotate about the corresponding second rotation axis (9).

7. The liquid or gaseous fuel burner according to claim 6, characterized in that, The linkage mechanism (23) further includes: a connecting rod (25) for connecting the second crank (24) to each other; and a connecting rod (27) for connecting the connecting rod (25) and the first crank (22) to each other.

8. The liquid or gaseous fuel burner according to claim 7, characterized in that, The connecting rod (25) is rotatably connected to the second crank (24) in the region of the corresponding second fulcrum axis (26), and the connecting rod (27) is rotatably connected to the connecting rod (25) in the region of the third fulcrum axis (28), and the connecting rod can be rotatably selectively connected to the first crank (22) in the region of the first fulcrum axis (29).

Images