CN107957068B

CN107957068B - Venturi tube and gas equipment thereof

Info

Publication number: CN107957068B
Application number: CN201610906294.3A
Authority: CN
Inventors: 王双飞; 朱高涛; 毕大岩; 余德君
Original assignee: AO Smith China Water Heater Co Ltd
Current assignee: AO Smith China Water Heater Co Ltd
Priority date: 2016-10-18
Filing date: 2016-10-18
Publication date: 2024-05-28
Anticipated expiration: 2036-10-18
Also published as: CN107957068A

Abstract

The application discloses a venturi tube and a gas device thereof, wherein the venturi tube comprises: the device comprises a contraction section with a gradually reduced cross section, a throat with a constant cross section and a diffusion section with a gradually increased cross section, which are sequentially arranged; the constriction section, the throat and the diffusion section form a gas flow passage of the venturi; at least two air inlet parts are arranged on the wall of the air flow channel; at least one of the at least two inlet portions is disposed upstream and downstream of at least one inlet portion along the gas flow direction within the gas flow path.

Description

Venturi tube and gas equipment thereof

Technical Field

The application relates to the technical field of gas equipment, in particular to a venturi tube and gas equipment thereof.

Background

The full premix combustion means that the fuel gas is fully mixed with air before the burner, the combustion mode of supplying air is not needed in the combustion process, the propagation speed of flame of the full premix combustion is high, and the combustion efficiency is high. The venturi is the device that mixes gas and air in the full premix burning, and the venturi that uses in the current full premix combustion system can make combustion system burn under the operating condition of little load can not normally go on, leads to combustion system to adjust less, influences user's use experience, for example, with regard to full premix hanging stove, the greater the regulation ratio, the greater the load adjustment range when heating and using hot water, the travelling comfort that the user used is higher, and when adjusting less, when heating and using hot water when operating in little load region, can't stably supply gas and cause the unstable of burning easily, lead to system operation stability relatively poor, the outlet water temperature deviation is great, and can make the durability of equipment decline moreover.

Disclosure of Invention

The inventor finds that the gas inlets of the existing mechanical venturi tube are usually arranged at the same position of the throat or on the same cross-section circumference of the throat, and as the gas pressures of all points on the same cross-section circumference are equal, the gas inlets have no interaction or mutual influence, the ratio of the total area of the gas inlets to the cross-section area of the venturi throat is constant, and the structure of the venturi tube can stably work in high-load operation, but can not stably burn in low-load operation, so that the regulation is lower. Based on the above findings, the inventor has found through many experiments that the venturi tube structure adopting the following technical scheme can make the combustion system obtain a better adjustment ratio, thereby improving the use experience of users.

The present application provides a venturi tube comprising: the device comprises a contraction section with a gradually reduced cross section, a throat with a constant cross section and a diffusion section with a gradually increased cross section, which are sequentially arranged; the constriction section, the throat and the diffusion section form a gas flow passage of the venturi;

at least two air inlet parts are arranged on the wall of the air flow channel; at least one of the at least two inlet portions is disposed upstream and downstream of at least one inlet portion along the gas flow direction within the gas flow path.

As a preferred embodiment, the at least two gas inlets are disposed upstream and downstream in the gas flow direction in the gas flow passage.

As a preferred embodiment, at least one of the air inlet portions is provided on the diffuser section, and the remaining air inlet portions are provided on the throat.

As a preferred embodiment, the ratio of the sum of the intake surface areas of the intake portions located on the diffuser section to the sum of the intake surface areas of the intake portions located on the throat is: 1:1-1:10.

As a preferred embodiment, the intake surface area of the intake portion is gradually smaller in the gas flow direction.

As a preferred embodiment, the area ratio of the total area of the air intake surfaces of the at least two air intake portions to the cross-sectional area of the throat is: 1:5-1:12.

As a preferred embodiment, at least one of said air inlet portions of said diffuser section is disposed adjacent said throat.

As a preferred embodiment, the distance between two adjacent gas inlet portions in the gas flow passage in the gas flow direction is 1 to 60mm.

As a preferred embodiment, the constriction section, throat and diffuser section are integrally formed.

As a preferred embodiment, the constriction, throat and diffuser are connected in sequence to form the venturi.

As a preferred embodiment, at least a part of the air inlet portions are located on the same longitudinal section of the venturi tube and on the same side of the venturi tube.

As a preferred embodiment, a part of the number of the air intake portions are located on the same circumference of the venturi tube.

As a preferred embodiment, the outer wall of the venturi tube is provided with a groove; the at least two air inlet portions communicate the groove with the gas flow passage.

As a preferred embodiment, the air inlet is an air inlet hole or a gap.

As a preferred embodiment, the number of the air inlet portions is two, wherein one air inlet portion is located in the throat and the other air inlet portion is located in the diffuser section.

The present application also provides a gas apparatus comprising:

A blower;

A gas valve for introducing gas;

The venturi of any preceding embodiment; the contraction section is communicated with the fan; the at least two air inlet parts are communicated with the air valve.

As a preferred embodiment, the venturi is connected upstream of the fan.

As a preferable implementation mode, the gas equipment is a fully premixed gas water heater or a fully premixed condensing wall-mounted furnace.

By means of the technical scheme, the venturi tube is provided with the at least two air inlet parts on the wall of the air flow channel, wherein at least one air inlet part is distributed in the air flow direction in the air flow channel in the upstream-downstream mode with at least one air inlet part, the air inlet parts distributed in the upstream-downstream mode can stably input fuel gas when the fan runs at low power or low rotation speed, and the fuel gas can be fully and stably combusted at the combustion side, so that the venturi tube in the embodiment can ensure stable combustion at the lower rotation speed or power of the fan, and improve the use experience of users.

Meanwhile, on the basis of stable combustion, compared with combustion equipment using the venturi tube with the existing structure, the combustion equipment using the venturi tube can stably burn at lower fan rotating speed or power, so that the combustion equipment can stably work under low load, and therefore, the combustion equipment using the venturi tube can obtain larger regulation ratio.

In addition, the venturi tube of the application has the advantages of realizing larger regulation ratio of combustion equipment by arranging the air inlet parts distributed in the upstream and downstream directions, having very simple structure, saving cost and convenient manufacture, and having very outstanding practical application value, and no complex structure is arranged on the existing structure of the venturi tube.

Specific embodiments of the invention are disclosed in detail below with reference to the following description and drawings, indicating the manner in which the principles of the invention may be employed. It should be understood that the embodiments of the invention are not limited in scope thereby. The embodiments of the invention include many variations, modifications and equivalents within the spirit and scope of the appended claims.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used herein is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.

FIG. 1 is a perspective view of a venturi provided by one embodiment of the present application;

FIG. 2 is a cross-sectional view of the venturi of FIG. 1;

FIG. 3 is a cross-sectional view of a venturi provided by another embodiment of the present application;

Fig. 4 is a perspective view of a portion of the venturi of fig. 3.

Detailed Description

In order to make the technical solution of the present application better understood by those skilled in the art, the technical solution of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, shall fall within the scope of the application.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1 to 4, a schematic structural diagram of a venturi tube 1 according to an embodiment of the present application is provided, and the venturi tube 1 is not limited to a fully premixed condensing wall-mounted boiler, but can also be applied to a fully premixed gas water heater, and of course, the venturi tube 1 is preferably applied to a fully premixed gas combustion technology.

In the present embodiment, as shown in fig. 1 to 4, the venturi tube 1 includes: a constriction section 10 with a gradually decreasing cross section, a throat 20 with a constant cross section, and a diffuser section 30 with a gradually increasing cross section are sequentially arranged; the constriction 10, throat 20, and diffuser 30 form the gas flow path 2 of the venturi 1; at least two air inlet parts 40 are arranged on the wall of the air flow channel 2; at least one of the at least two inlet portions 40 is disposed upstream and downstream of at least one inlet portion 40 in the gas flow direction within the gas flow path 2.

The inventors have found through a number of experiments that the above-described venturi 1 is capable of improving the turndown ratio of the combustion system, and according to years of research experience, it is believed that it may exist by the following mechanism or working process:

At least one of the inlet portions 40 is disposed in the venturi 1 in a direction of gas flow in the gas flow path 2 and upstream and downstream of at least one of the inlet portions 40. When the air flow passes through the air flow passage 2, there may be different pressure values in the air flow passage 2 along the air flow direction of the air inlet portion 40 having an upstream-downstream positional relationship.

When the flow rate of air flowing through the gas flow passage 2 is high, all the gas inlets 40 can stably input gas, and the input gas amount and the air amount have a preferable ratio, and the combustion system can stably and sufficiently burn at the ratio.

When the flow rate through the gas flow passage 2 is low, since there may be different pressure values in the gas flow direction of the gas inlet portion 40 having the upstream-downstream positional relationship, some of the gas inlet portion 40 can stably input the gas, and the gas amount of the input gas is a preferable ratio to the air, and some of the gas inlet portion 40 does not intake the gas. After the venturi tube 1 is applied to a full premix combustion system, combustion can be stably carried out when a fan runs at a higher rotating speed and a lower rotating speed, so that the combustion system has a larger regulating ratio.

Specifically, when a part of the air inlet 40 of the venturi tube 1 is provided in the throat and a part thereof is provided in the diffuser, the pressure of the air in the throat is low, and the pressure of the air flow gradually increases when the air flows in the diffuser. When the diameter of the air inlet portion 40 is designed within a certain range, a position where the pressure of the mixed gas is larger than the pressure in the air inlet portion 40 can appear in the diffusion section, so that the air inlet portion 40 at the position is sealed from feeding fuel gas, and the air inlet portion 40 on the throat can form stable air inlet, thereby ensuring that the air-fuel ratio of the mixed gas is normal, and the combustion equipment can stably burn under small load.

In addition, other possible mechanisms are: in the venturi tube 1 of the present embodiment, there may be a mutual promotion effect between the air intake portions 40 distributed upstream and downstream, that is, one air intake portion 40 may promote the gas input of the air intake portion 40 located upstream or downstream thereof, so that even under a low-rotation-speed fan, the air intake portion 40 may still input a sufficient amount of gas, ensuring the stability of combustion.

Among them, the inventors have found, based on a plurality of experiments and through careful analysis, that the upstream intake portion 40 may have a more remarkable promoting effect on the downstream intake portion 40, and that the promoting effect is more intense when the two intake portions 40 in the upstream-downstream relationship are closer together.

Specifically, one possible interaction is that the air inlet portion 40 on the throat may cause a lower pressure in a region near the air inlet portion 40 on the diffuser due to injection, so that the air inlet amount of the air inlet portion 40 on the diffuser may be more and more stable than the air inlet amount of the air inlet portion 40 on the throat, thereby ensuring that the air-fuel ratio of the mixed gas is normal, and the combustion apparatus is stable in low load.

By means of the above technical solution, the venturi tube 1 of the present application has at least two air inlet portions 40 provided on the wall of the air flow channel 2, wherein at least one air inlet portion 40 is distributed upstream and downstream with at least one air inlet portion 40 along the air flow direction in the air flow channel 2, and the air inlet portions 40 distributed upstream and downstream can stably input fuel gas and can fully and stably burn on the combustion side when the fan runs at low power or low rotation speed, so that the venturi tube 1 of the present embodiment can ensure stable combustion at low rotation speed or power of the fan, and improve the use experience of users.

Meanwhile, on the basis of stable combustion, compared with combustion equipment using the venturi tube with the existing structure, the combustion equipment using the venturi tube 1 can stably burn at a lower fan rotating speed or power, so that the combustion equipment can stably work under a low load, and therefore, a larger regulation ratio can be obtained by using the combustion equipment using the venturi tube 1.

In addition, the venturi tube of the application has a larger adjusting ratio by arranging the air inlet parts 40 distributed in the upstream and downstream, has a very simple structure, saves cost, is convenient to manufacture and has very outstanding practical application value, and the existing structure of the venturi tube is not required to be provided with a complex structure.

With continued reference to fig. 1 and 2, in the present embodiment, the constriction 10, the throat 20 and the diffuser 30 are arranged in sequence. Wherein the constriction 10 has an inlet for the inlet air which, in the actual configuration, is provided at the end of the constriction 10 remote from the throat 20, the inlet having the greatest cross-section (area) over the constriction 10.

Accordingly, the diffuser section 30 is configured opposite the constrictor section 10, with the diffuser section 30 having a gradually increasing cross-section. The diffuser section 30 has an air outlet for outputting a mixed gas of fuel gas and air, which is provided at an end of the diffuser section 30 remote from the throat 20, and which has a maximum cross section (volume) on the diffuser section 30.

The throat 20 is disposed between the diverging section 30 and the converging section 10, and the cross-sectional area of the throat 20 remains unchanged. The cross-sectional shapes of the diffuser 30, the throat 20, and the constriction 10 may be the same, for example, all three may be circular, polygonal, or irregular, and the cross-sectional shapes of the diffuser 30, the throat 20, and the constriction 10 may be different, for example, one may be circular, the other may be polygonal, and the other may be irregular. The present application is not limited to the specific cross-sectional shapes of the diffuser section 30, the throat 20, and the constrictor 10, but, of course, the cross-sectional shapes of the diffuser section 30, the throat 20, and the constrictor 10 are all preferably circular.

In this embodiment, the contraction section 10, the throat 20, and the diffuser section 30 may be integrally formed as shown in fig. 1 to 4. In practice, the constriction 10, throat 20, and diffuser 30 may be machined directly into a tubular body by cutting. In this embodiment, to accommodate this configuration, the air inlet 40 may be an air inlet hole in the wall of the venturi tube 1, which communicates the gas flow passage 2 with the combustion gas.

Of course, in another possible embodiment, the constriction 10, the throat 20, and the diffuser 30 may be connected in series to form the venturi. In this embodiment, the adjacent two of the contraction section 10, the throat 20, and the diffusion section 30 may be connected to each other in a detachable manner, such as a threaded connection (an end portion is provided with an internal thread and an external thread), a flange connection, or the like, or in a non-detachable manner, such as welding. It can be seen that there are a variety of connection means in the constriction 10, throat 20, and diffuser 30, and the application is not particularly limited.

In this embodiment, the contraction section 10, the throat 20, and the diffusion section 30 may be separately provided. The air inlet 40 is a gap between two adjacent of the constriction 10, the throat 20, and the diffuser 30. In this embodiment, the contraction section 10, the throat 20, and the diffusion section 30 may be independent structures, and a gap is formed between the three, and the gas may be introduced into the gap. The gap may be a complete circle or a partial arc, and the present application is not limited in any way.

Note that, when the air inlet 40 is a gap, the air inlet 40 may be provided in the contraction section 10, the throat 20, and the diffuser 30, regardless of the above embodiment. For example, the contraction section 10 is divided into two parts in the contraction direction, and a gap between the two parts forms an air inlet portion 40, and the throat 20 and the diffuser section 30 are similar to each other, and are not described in detail herein.

In the present embodiment, at least two gas inlet portions 40 are provided on the wall of the gas flow passage 2. As shown in fig. 1 and 2, at least two air inlet portions 40 are located between the air inlet (not numbered) and the air outlet (not numbered). Wherein at least one inlet portion 40 is disposed upstream and downstream of at least one inlet portion 40 along the gas flow direction in the gas flow path 2. In the present embodiment, the air intake portions 40 may be arranged in one or more rows, or may be circumferentially staggered, and the present application is not limited in any way, and at least a part of the air intake portions 40 may be disposed in an upstream-downstream distribution.

In a specific embodiment, to obtain a preferred adjustment ratio, the at least two air inlet portions 40 are disposed sequentially upstream and downstream along the air flow direction in the air flow channel 2. In this embodiment, as shown in fig. 1 and 2, all the air intake portions 40 may be distributed upstream and downstream from each other.

Of course, in this embodiment, although all the air inlet portions 40 are disposed upstream and downstream, the arrangement (or distribution) of all the air inlet portions 40 is not limited in this embodiment, and the air inlet portions 40 may be disposed regularly, for example, may be disposed in a single row, spiral, or the like along the air flow direction, or may be disposed irregularly along the air flow direction.

In this embodiment, at least one of the air inlet portions 40 may be provided in the diffuser 30, and the remaining air inlet portions 40 may be provided in the throat 20. In the present embodiment, a part of the number of air intake portions 40 are provided on the diffuser 30, and another part of the number of air intake portions 40 are provided on the throat 20.

In the present embodiment, the number of the air inlet 40 in the diffuser 30 and the throat 20 is not limited, and may be one or a plurality of. Of course, as shown in fig. 1 and2, the number of the air inlet portions 40 may be two, wherein one air inlet portion 41 is located in the throat 20, and the other air inlet portion 42 is located in the diffuser 30. As shown in fig. 3 and 4, the plurality of air intake portions 41 may be located in the throat 20, and the plurality of air intake portions 42 may be located in the diffuser 30.

The distribution of the air inlet portions 40 on the diffuser 30 and the throat 20 is not limited in this embodiment, and the air inlet portions 40 may be regularly arranged, for example, may be arranged in a single row, a spiral, or the like along the air flow direction, or may be irregularly arranged along the air flow direction.

Preferably, at least one of the air inlet portions 40 of the diffuser section 30 may be positioned adjacent to the throat 20. As shown in fig. 1-3, the air inlet 40 at the diffuser section 30 is positioned adjacent to the junction (or transition) of the throat 20 and the air inlet 40.

Based on the above analysis mechanism, through the arrangement, the pressure of the area near the air inlet portion 40 on the diffuser near the throat is lower due to the injection action of the air inlet portion 40 on the throat, so that the air inflow of the air inlet portion 40 on the diffuser may be more and more stable than the air inflow of the air inlet portion 40 on the throat, thereby ensuring the better ratio of the gas amount of the input gas to the air and ensuring the stable combustion.

Specifically, the total intake surface area of the intake portion 40 on the throat 20 (the intake surface of the intake portion may be the cross-section of the intake portion) is greater than or equal to the total intake surface area of the intake portion 40 on the diffuser section 30. Further, the ratio of the sum of the intake surface areas of the intake portions 40 located on the diffuser 30 to the sum of the intake surface areas of the intake portions 40 located on the throat 20 is: 1:1-1:10 (including the cases of 1:1 and 1:10). To achieve the above area ratio, the intake surface area of the intake portion 40 may be gradually smaller in the gas flow direction.

In the present embodiment, the air intake portion 40 is used for inputting fuel gas, wherein the fuel gas and air are mixed in the gas flow passage 2 of the venturi tube 1 to form a mixed gas, and the air-fuel ratio (air-fuel volume or concentration ratio) in the mixed gas directly affects the quality of downstream combustion. Considering the factors influencing the air-fuel ratio, including the flow rate and the air inlet area of air, the flow rate and the air inlet area of fuel gas, wherein the flow rates of air and fuel gas are greatly influenced by the rotating speed or the power of the fan, and the fan is set to operate in a certain rotating speed range in practical application.

For the air and gas intake area, taking into account that it is difficult to change during use, obtaining a suitable air and gas intake area is critical to obtaining a better air-fuel ratio. The inventors have found through many experiments that, when the area ratio of the total area of the air inlet surfaces of the at least two air inlet portions 40 (i.e. the sum of the air inlet surface areas of all air inlet portions 40) to the cross-sectional area of the throat 20 is 1:5-1:12 (including the cases of 1:5 and 1:12), the air inlet portion of the present embodiment can be mixed with the input air in a better ratio, and the fuel gas can be completely and fully combusted on the combustion side.

In the present embodiment, the distance between two adjacent gas inlet portions 40 in the gas flow path 2 in the gas flow direction may be 1 to 60mm. The arrangement of two adjacent gas inlets 40 in the gas flow direction is not limited, and they may be located at the same position (such as the top, the bottom, or the side in fig. 1) of different circumferences, or they may be located at different positions of different circumferences. In the present embodiment, only the two gas inlets 40 need to have an upstream-downstream relationship therebetween in the upward vicinity of the gas flow.

With continued reference to fig. 1 and 2, to facilitate connection of the gas valve, at least a portion of the intake portions 40 are located on the same longitudinal section of the venturi tube 1 and on the same side of the venturi tube 1. The longitudinal section is a section parallel to the longitudinal direction or the flow direction of the gas flow path 2 (or the venturi tube 1).

Specifically, a groove 50 is formed on the outer wall of the venturi tube 1; the at least two inlet portions 40 communicate the recess 50 with the gas flow passage 2. The groove 50 can be conveniently connected with a gas valve, and threads can be arranged in the groove 50, so that a corrugated pipe and an aluminum pipe are arranged to be connected with the gas valve. As can be seen from fig. 1, the groove 50 penetrates the wall of the venturi tube 1 with the air inlet portion 40 (the air inlet portion 40 is an air inlet hole), and the two air inlet portions 40 are connected to the bottom of the same groove 50, wherein threads may be provided on the inner wall of the groove 50 to connect the gas valve through the gas pipeline.

In addition, as shown in fig. 3 and 4, a part of the number of the air intake portions 40 may be located on the same circumference of the venturi tube 1. For example, the air inlet portions 40 of the throat 20 may be located on the same circumference and spaced apart circumferentially independently of each other.

Another embodiment of the present application also provides a gas apparatus including: a blower; a gas valve for introducing gas; the venturi of any preceding embodiment; the venturi tube is communicated with the fan; the at least two air inlet parts are communicated with the air valve. The shape, structure and function of the venturi tube can refer to the above embodiments, and the description of the embodiments is omitted.

In this embodiment, the venturi may be disposed upstream or downstream of the blower, and may function to premix fuel gas and air, and preferably, the venturi is connected upstream of the blower.

In this embodiment, the gas device is a fully premixed gas water heater or a fully premixed condensing wall-mounted boiler.

Any numerical value recited herein includes all values of the lower and upper values that increment by one unit from the lower value to the upper value, as long as there is a spacing of at least two units between any lower value and any higher value. For example, if it is stated that the number of components or the value of a process variable (e.g., temperature, pressure, time, etc.) is from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, then the purpose is to explicitly list such values as 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc. in this specification as well. For values less than 1, one unit is suitably considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples that are intended to be explicitly recited in this description, and all possible combinations of values recited between the lowest value and the highest value are believed to be explicitly stated in the description in a similar manner.

Unless otherwise indicated, all ranges include endpoints and all numbers between endpoints. "about" or "approximately" as used with a range is applicable to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30," including at least the indicated endpoints.

All articles and references, including patent applications and publications, disclosed herein are incorporated by reference for all purposes. The term "consisting essentially of …" describing a combination shall include the identified element, ingredient, component or step as well as other elements, ingredients, components or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprises" or "comprising" to describe combinations of elements, components, or steps herein also contemplates embodiments consisting essentially of such elements, components, or steps. By using the term "may" herein, it is intended that any attribute described as "may" be included is optional.

Multiple elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step may be divided into separate plural elements, components, parts or steps. The disclosure of "a" or "an" to describe an element, component, section or step is not intended to exclude other elements, components, sections or steps.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of the present teachings should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated herein by reference for the purpose of completeness. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to forego such subject matter, nor should the inventors regard such subject matter as not be considered to be part of the disclosed subject matter.

Claims

1. A venturi tube, comprising: the device comprises a contraction section with a gradually reduced cross section, a throat with a constant cross section and a diffusion section with a gradually increased cross section, which are sequentially arranged; the constriction section, the throat and the diffusion section form a gas flow passage of the venturi;

At least two air inlet parts are arranged on the wall of the air flow channel; at least one of the at least two air inlet parts is distributed with at least one air inlet part in the upstream and downstream along the air flow direction in the air flow channel;

at least one air inlet part is arranged on the diffusion section, and the rest air inlet parts are arranged on the throat;

The inlet of the gas flow passage is used for inputting air, and the air inlet part is used for inputting fuel gas; the ratio of the sum of the intake surface areas of the intake portions located on the diffuser to the sum of the intake surface areas of the intake portions located on the throat is: 1:1-1:10; the contraction section, the throat and the diffusion section are of an integrated structure.

2. The venturi according to claim 1, wherein: the at least two air inlet parts are distributed upstream and downstream in sequence along the air flow direction in the air flow channel.

3. The venturi according to claim 1, wherein: the intake surface area of the intake portion becomes gradually smaller in the gas flow direction.

4. A venturi according to any one of claims 1 to 3, wherein: the area ratio of the total area of the air inlet surfaces of the at least two air inlet parts to the cross section of the throat is: 1:5-1:12.

5. A venturi according to any one of claims 1 to 3, wherein: at least one of the air inlet portions at the diffuser section is disposed adjacent the throat.

6. A venturi according to any one of claims 1 to 3, wherein: the distance between two adjacent gas inlet parts in the gas flow passage in the upward direction is 1-60mm.

7. The venturi according to claim 1, wherein: at least a part of the air inlet portions are located on the same longitudinal section of the venturi tube and on the same side of the venturi tube.

8. The venturi according to claim 1, wherein: a partial number of the air intake portions are located on the same circumference of the venturi tube.

9. The venturi according to claim 1, wherein: a groove is formed in the outer wall of the venturi tube; the at least two air inlet portions communicate the groove with the gas flow passage.

10. The venturi according to claim 1, wherein: the air inlet part is an air inlet hole or a gap.

11. The venturi according to claim 1, wherein: the number of the air inlet parts is two, wherein one air inlet part is positioned in the throat, and the other air inlet part is positioned in the diffusion section.

12. A gas plant, characterized by comprising:

A blower;

A gas valve for introducing gas;

A venturi as claimed in any one of claims 1 to 11; the venturi tube is communicated with the fan; the at least two air inlet parts are communicated with the air valve.

13. The gas-fired apparatus of claim 12, wherein: the venturi is connected upstream of the fan.

14. The gas-fired apparatus of claim 12, wherein: the gas equipment is a full premix gas water heater or a full premix condensing wall-mounted furnace.