Multi-cavity gas and air mixing device

Abstract

A multi-cavity gas-air mixing device includes at least two mixing cavities each having an air inlet and a mixture outlet communicated with a combustor, wherein each of the mixing cavities has a built-in gas pipeline, each of the gas pipelines is provided with a gas jet, and the orientation of the gas jet is intersected with a flow direction of air entering into the mixing cavities. The device effectively segments the gas-air mixer and achieves a large load regulation ratio, without producing condensate water at any load segment, thereby improving the system reliability and service life. The built-in gas pipeline not only actively controls the fuel in the open-close control pipeline, but also reduces the volume of the mixer and largely decreases the cost.

Claims

1. A multi-cavity gas-air mixing device, comprising at least two mixing cavities each having an air inlet and a mixture outlet communicated with a combustor, wherein each of the mixing cavities has a built-in gas pipeline inside, each of the gas pipelines is provided with a gas jet, and the orientation of each gas jet is intersected with a flow direction of air entering into the mixing cavities and the air flow flows over the gas pipelines, and wherein the gas pipelines in the at least two mixing cavities are communicated with each other inside the mixing cavities and the communicated gas pipelines comprise at least one open-close control pipeline, and wherein the communicated gas pipelines further comprise at least one normally open pipeline connected to an external gas delivery pipeline, and a gas on-off valve that controls the open-close control pipeline to be opened and closed is provided between the open-close control pipeline and the normally open pipeline, and the gas on-off valve is positioned at least partially within one of the mixing cavities, and the normally open pipeline has an extension section extending into an interior of the open-close control pipeline and provided with a gas outlet which is in communication with the open-close control pipeline and is controlled by the gas on-off valve to be opened and closed.

2. The multi-cavity gas-air mixing device according to claim 1, wherein the gas on-off valve is a solenoid valve having a seal movably blocking between the open-close control pipeline and the normally open pipeline.

3. The multi-cavity gas-air mixing device according to claim 1, wherein the gas pipeline is provided as being perpendicular to an air flow path of the mixing cavity.

4. The multi-cavity gas-air mixing device according to claim 1, wherein the mixing cavity is of Venturi type, and the Venturi type mixing cavity has a convergent throat segment and a divergent mixing segment.

5. The multi-cavity gas-air mixing device according to claim 1, wherein the at least two mixing cavities are arranged in parallel, the two adjacent mixing cavities are partitioned from each other through a partition board, and the gas pipeline is provided throughout the mixing cavities through a mounting hole opened on the partition board.

6. The multi-cavity gas-air mixing device according to claim 1, wherein a distributor through which the mixture is evenly delivered to the combustor is provided at an upper portion of the mixing cavity.

7. The multi-cavity gas-air mixing device according to claim 6, wherein the distributor is a flat plate having a porous structure.

8. The multi-cavity gas-air mixing device according to claim 1, wherein the at least two mixing cavities comprises a first mixing cavity and a second mixing cavity; the built-in gas pipeline of the first mixing cavity is the normally open pipeline and the built-in gas pipeline of the second mixing cavity is the open-close control pipeline.

9. The multi-cavity gas-air mixing device according to claim 8, wherein the gas jet on each of the normally open and the open-close control pipelines comprises a plurality of gas jets, and a ratio of a sum of areas of the plurality of gas jets on the normally open pipeline to a sum of areas of the plurality of gas jets on the open-close control pipeline is between 1:3 and 1:1.

10. The multi-cavity gas-air mixing device according to claim 1, wherein the open-close control pipeline and the normally open pipeline are coaxial with each other about a longitudinal axis.

11. The multi-cavity gas-air mixing device of claim 10, wherein the gas outlet is in a plane perpendicular to the longitudinal axis and the gas on-off valve moves axially along the longitudinal axis to close the gas outlet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings introduced herein are just for the purpose of explanation, rather than restricting the scope of the disclosure of the present invention. In addition, the shapes and scales of various parts in the accompanying drawings are just schematic to promote the understanding of the present invention, rather than restricting the shapes and scales of those parts in the present invention. Being taught by the present invention, a person skilled in the art can implement the present invention by selecting various possible shapes and scales according to the specific conditions.

(2) FIG. 1 is a characteristic diagram of an existing partially-premixed sectionalized combustion;

(3) FIG. 2 is a stereo structure schematic diagram of Embodiment 1 of a multi-cavity gas-air mixing device of the present invention;

(4) FIG. 3 is a structure schematic diagram of cross-section A-A of FIG. 2;

(5) FIG. 4 is a structure schematic diagram of cross-section B-B of FIG. 3; and

(6) FIG. 5 is a structure schematic diagram of Embodiment 2 of a multi-cavity gas-air mixing device of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

(7) 1 first mixing cavity; 11 first air inlet; 12 first gas pipeline; 2 second mixing cavity; 21 second air inlet; 22 second gas pipeline; 3 third mixing cavity; 32 third gas pipeline; 4 gas jet; 5 gas on-off valve; 501 sealing part; 51 first solenoid valve; 52 second solenoid valve; 6 partition board; 7 throat segment; 8 mixing segment.

DESCRIPTION OF THE EMBODIMENTS

(8) The details of the present invention will be clearer in conjunction with the accompanying drawings and the embodiments of the present invention. However, the embodiments of the present invention described herein are just for the purpose of explanation of the present invention, rather than being construed as restrictions to the present invention in any way. Being taught by the present invention, a person skilled in the art can conceive any possible modification based on the present invention, which shall be deemed as falling within the scope of the present invention.

(9) The present invention proposes a multi-cavity gas-air mixing device, comprising at least two mixing cavities each having an air inlet, a mixture outlet communicated with a combustor, and a built-in gas pipeline, which reduces the entire volume of the mixing device. Each gas pipeline is provided with a gas jet and the orientation of the gas jet is intersected with a flow direction of air entering into the mixing cavities. Thus air and gas are sufficiently mixed in the mixing cavity.

(10) As illustrated in FIGS. 2 to 4, FIG. 2 is a stereo structure schematic diagram of Embodiment 1 of a multi-cavity gas-air mixing device of the present invention, FIG. 3 is a structure schematic diagram of cross-section A-A of FIG. 2, and FIG. 4 is a structure schematic diagram of cross-section B-B of FIG. 3. The multi-cavity gas-air mixing device of the present invention comprises: a first mixing cavity 1, a second mixing cavity 2, a first air inlet 11, a second air inlet 21, a first gas pipeline 12, a second gas pipeline 22, a gas on-off valve 5, and a mixture outlet (not illustrated). The first mixing cavity 1 has an air inlet 11 and a mixture outlet, and the second mixing cavity 2 has an air inlet 21 and a mixture outlet, wherein the air inlet 11, 21 is communicated with atmosphere to supply air through a fan, such that external air enters the mixing cavity 1, 2 and flows along an air passage formed by an inner cavity of the mixing cavity. The mixture outlet is connected to the combustor to supply mixture to the mixing cavity. As illustrated in FIGS. 2 and 3, the first mixing cavity 1 has a built-in first gas pipeline 12 with one end connected to a gas delivery pipeline and a gas regulating valve (the arrow in FIG. 3 indicating a gas input direction) that controls the amount of gas introduced into the first gas pipeline 12, and the other end connected to a second gas pipeline 22 built in the second mixing cavity 2 such that the gas can be delivered to the second gas pipeline 22 through the first gas pipeline 12. The first gas pipeline 12 and the second gas pipeline 22 each has a gas jet 4. Gas is jetted into the mixer by the gas jet 4 provided in the gas pipeline of the mixer, and the orientation of the gas jet 4 is intersected with a flow direction of air entering into the mixing cavity 1, 2, such that the gas flow in the mixing cavity 1, 2 is intersected and mixed with the air flow. The gas flow changes its direction after the mixing and flows with the air flow, which increases the actual length of a gas-air mixing path in the mixing cavity 1, 2, thereby sufficiently mixing gas and air while reducing the entire volume of the device. Of course, the present invention can also arrange three, four or more mixing cavities in parallel, provided that the gas flow in the mixing cavity 1, 2 is intersected and mixed with the air flow.

(11) Further, the gas pipeline 12 is provided as being perpendicular to the air flow path of the mixing cavity 1, and the gas pipeline 22 is provided as being perpendicular to the air flow path of the mixing cavity 2, such that the gas and air are mixed more sufficiently, and the entire volume of the combustor is further reduced.

(12) In this embodiment, as illustrated in FIGS. 2 and 3, the first gas pipeline 12 and the second gas pipeline 22 are communicated with each other, and a gas on-off valve 5 that controls the second gas pipeline 22 to be opened and closed is provided between the first gas pipeline 12 and the second gas pipeline 22. The first gas pipeline 12 is a normally open pipeline, i.e., it is remains a normally open state, and the second gas pipeline 22 is an open-close control pipeline, i.e., its opening or close is controlled through the gas on-off valve 5 to realize a sectionalized combustion function. Thus, not only the load regulation ratio of the system is increased, but also the probability of condensate water production by the flue gas is efficiently reduced. In the present invention, three, four or more gas pipelines may also be adaptively provided depending on the number of the mixing cavities. The gas pipelines are orderly communicated, including at least one open-close control pipeline and at least one normally open pipeline. The normally open pipeline is connected to the external gas delivery pipeline, and a connection pipe of the open-close control pipeline is provided with a gas on-off valve that controls the open-close control pipeline to be opened or closed.

(13) Further, as illustrated in FIGS. 2 and 3, in this embodiment the gas on-off valve 5 is a solenoid valve, which has a sealing part 501 movably provided between the first gas pipeline 12 and the second gas pipeline 22 from an outer side of the second gas pipeline 22 to block the inlet of the second gas pipeline 22, so as to realize a closing function of the second gas pipeline 22. When the second gas pipeline 22 is to be opened, it only needs to move the sealing part 501 to one side of the second gas pipeline 22 such that the first gas pipeline 12 and the second gas pipeline 22 are communicated with each other again. In the present invention, the gas on-off valve 5 may also be a stop valve, a ball valve, a butterfly valve, a plunger valve or any other known switch valve provided that the opening and closing function of the open-close control pipeline can be realized, which is not limited herein.

(14) Further, a ratio of a sum of areas of the gas jets 4 on the first gas pipeline 12 to a sum of areas of the gas jets 4 on the second gas pipeline 22 is between 1:3 and 1:1.

(15) Further, as illustrated in FIGS. 2 and 3, the first mixing cavity 1 and the second mixing cavity 2 are partitioned from each other through a partition board 6, and the first gas pipeline 12 and the second gas pipeline 22 are provided throughout the first mixing cavity 1 and the second mixing cavity 2 through mounting holes opened on the partition board 6, such that the structure is more compact.

(16) Further, distribution structures are provided at upper portions of the first mixing cavity 1 and the second mixing cavity 2, such that the mixture is evenly delivered to the combustor through the distribution structures. Preferably, the distribution structure is a flat plate having a porous structure.

(17) Further, as illustrated in FIG. 4, the first mixing cavity 1 and the second mixing cavity 2 are of Venturi type. The Venturi type mixing cavity 1, 2 has a convergent throat segment 7 and a divergent mixing segment 8. In this embodiment, the gas jets 4 are located at the front side of the Venturi throat segment 7. The gas and air are firstly mixed in the region that is the front side of the Venturi throat segment 7, then diffused downstream the throat segment 7 after being compressed and accelerated by the throat segment 7, prefixed at a subsequent large radian corner of the Venturi type mixing cavity and several places where the flow channel is deformed, and sufficiently mixed before reaching the combustor, so as to ensure a sufficient combustion and a low pollutant emission.

(18) Another optional embodiment of the present invention is illustrated in FIG. 5, which is a structure schematic diagram of Embodiment 2 of a multi-cavity gas-air mixing device of the present invention. This embodiment differs from Embodiment 1 in that the mixing cavity may be further divided into a first mixing cavity 1, a second mixing cavity 2 and a third mixing cavity 3, and the device further comprises an air inlet, a first gas pipeline 12, a second gas pipeline 22, a third gas pipeline 32, a first solenoid valve 51, a second solenoid valve 52, and a mixture outlet. In which, the first gas pipeline is connected to the second gas pipeline 22 and the third gas pipeline 32, respectively, and a gas sealing platform is provided at the joint to control the second gas pipeline 22 and the third gas pipeline 32 to be opened and closed through engagement and disengagement between the sealing part 501 of the solenoid valve 51, 52 and the gas sealing platform. Through the structure design of the embodiment, the mixing device may be divided into three segments, thereby further increasing the combustion load regulation ratio and being more beneficial to the high power system.

(19) The multi-cavity gas-air mixing device of the present invention may be manufactured in a way of integral molding, and the material may be aluminum or plastics such as PPS.

(20) In conclusion, the present invention integrates the gas injection device with the mixer, such that the gas-air mixer has the function of sectionalized combustion and the efficiency is high under a large load, thereby not only increasing the load regulation ratio of the system, but also efficiently reducing the probability of condensate water production by the flue gas because no condensate water is produced under a small load. Meanwhile, the gas pipeline is built in the mixer such that gas and air are mixed more sufficiently and evenly, which efficiently reduces the combustion pollutant emission, optimizes the size of the mixer, and achieves the purpose of decreasing the system volume, thereby largely reducing the total cost and representing a notable technical progress.

(21) The detailed descriptions of the above embodiments are just used to explain the present invention for a better understanding. But those descriptions cannot be construed as limitations to the present invention in any reason, in particular, the features described in different embodiments can be combined arbitrarily to form other embodiments. Unless otherwise specified explicitly, those features shall be understood as being applicable to any embodiment rather than those described.