VENTURI FOR BOILER

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Korean Patent Application No. 10-2024-0202256, filed in the Korean Intellectual Property Office on December 31, 2024, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a venturi for a boiler, and more particularly, to a venturi for a boiler, in which a flow rate of air and a flow rate of gas may be adjusted simultaneously and may be adjusted in three steps.

BACKGROUND

Generally, combustion devices, such as boilers and water heaters that are used for heating and supplying hot water, are classified into oil boilers, gas boilers, electric boilers, and water heaters according to the type of fuel supplied, and they are variously developed and used depending on installation purposes.

A performance of combustion appliances may be evaluated by a turndown ratio (TDR). The turndown ratio refers to a ratio of a maximum gas consumption to a minimum gas consumption in a gas combustion device, in which an amount of gas is variably adjusted. The turndown ratio (TDR) is limited depending on whether a stable flame may be maintained under a minimum gas consumption condition.

As a value of the turndown ratio (TDR) increases, convenience of gas boilers and water heaters that provide heating and hot water may be increased. When a value of the turndown ratio (TDR) is small and the combustion device is operated in an area, in which heating and hot-water loads are small, the combustion device may undergo frequent on/off operations. Frequent on/off operations of the combustion device may increase a deviation of temperature control and may degrade durability of the device.

Accordingly, to overcome these problems, various methods have been developed to improve a turndown ratio (TDR) of combustion devices, which is applied to the combustion appliances. For example, a method for improving the turndown ratio by partitioning paths through which air and gas are supplied into two or more areas, respectively, and opening or closing each air/gas passage in correspondence to an output of the combustion device so that combustion stability is enhanced even at low output, is used.

SUMMARY

The present disclosure has been made to solve the above-mentioned problems occurring in the prior art while advantages achieved by the prior art are maintained intact.

An aspect of the present disclosure provides a venturi that may improve a turndown ratio (TDR) by adjusting a flow rate of air and gas in three steps.

The technical problems to be solved by the present disclosure are not limited to the aforementioned problems, and any other technical problems not mentioned herein will be clearly understood from the following description by those skilled in the art to which the present disclosure pertains.

According to an aspect of the present disclosure, a venturi includes a housing, in which an air passage that is opened along a reference direction, a first gas passage that extends from the air passage, a second gas passage that extends from one side of the first gas passage, and a third gas passage that extends from an opposite side of the first gas passage are formed, a first opening/closing part that opens and closes the second gas passage in an interior of the housing, a second opening/closing part that opens and closes the third gas passage in the interior of the housing, and a flow rate adjuster, at least a portion of which is disposed in the interior of the housing and that adjusts a flow rate of air that flows through the air passage and supply of gas through the second gas passage or the third gas passage, and the flow rate adjuster includes a shaft that is rotatably coupled to the housing and that passes through the air passage in an upward/downward direction that is perpendicular to the reference direction, a cam that is integrally and rotatably coupled to the shaft and that applies or releases an external force to the first opening/closing part and the second opening/closing part to control opening and closing of the second gas passage and the third gas passage, and a blade that is integrally and rotatably coupled to the shaft and provided with a plurality of wings that adjusts a degree, to which a portion in an interior of the air passage is opened.

The housing may include a housing body, in which the air passage, the first gas passage, the second gas passage, and the third gas passage are formed, and a guide pipe that is disposed in an interior of a front part of the air passage and that guides a flow of air, the guide pipe may include an air inlet hole that introduces air from outside, and an air through-hole that allows the introduced air to flow toward a rear part of the air passage, and a degree, to which the air through-hole is opened, is adjusted by the blade.

The blade may include a body part that is coupled to the shaft, a first wing part that extends from the body part and in which at least one through-hole is formed, and a second wing part that extends from the body part to form a specific angle with the first wing part and in which more through-holes than the first wing part are formed.

An angle between the first wing part and the second wing part, which is measured from the first wing part in a first rotational direction, is a first angle, an angle between the first wing part and the second wing part, which is measured from the first wing part in a direction opposite to the first rotational direction, may be a second angle greater than the first angle, and the first angle and the second angle may be both obtuse angles.

The flow rate adjuster may adjust a flow rate of air in three steps by causing the air through-hole to be covered by any one of the first wing part and the second wing part or causing the air through-hole to be fully opened, based on rotation of the shaft.

The flow rate adjuster may adjust a flow rate of gas in three steps by causing the first opening/closing part and the second opening/closing part to close or open both the second gas passage and the third gas passage, or causing only the first opening/closing part to open the second gas passage, while the cam is rotated together with the blade.

When a state, in which the air through-hole is covered by the first wing part, is defined as a first operation mode, a state, in which the air through-hole is covered by the second wing part, is defined as a second operation mode, and a state, in which the air through-hole is fully opened, is defined as a third operation mode, in the first operation mode, the second gas passage and the third gas passage may be closed and gas may be supplied through the first gas passage, in the second operation mode, the third gas passage may be closed and the second gas passage may be opened, and gas may be supplied through the first gas passage and the second gas passage, and in the third operation mode, the second gas passage and the third gas passage may be opened, and gas may be supplied through the first gas passage, the second gas passage, and the third gas passage.

The cam may include a base part that is coupled to the shaft, a first protruding part that is provided at a lower end of the base part, and a second protruding part that is provided at an upper end of the base part and protrudes in a direction different from the first protruding part, the first protruding part may be configured to linearly move at least a portion of the first opening/closing part based on a rotational motion to open or close the second gas passage, and the second protruding part may be configured to linearly move at least a portion of the second opening/closing part based on a rotational motion to open or close the third gas passage.

Each of the first opening/closing part and the second opening/closing part may include a cylinder that is disposed in interiors of the second gas passage and the third gas passage and communicates an outside of the housing with the first gas passage, a rod, at least a portion of which is inserted into the cylinder and that is movable in a direction that is perpendicular to an upward/downward direction by an external force, and a disk that is coupled to the rod and that controls a flow of gas between an interior of the cylinder and the first gas passage in the interior of the cylinder.

The cylinder may be provided with a gas discharge hole on an outer surface facing the first gas passage, and the first protruding part and the second protruding part may press the rod to move the disk in a direction more distant from the gas discharge hole, so that the second gas passage and the third gas passage are opened.

Each of the first opening/closing part and the second opening/closing part further may include a spring that is disposed between the disk and the cylinder, and the spring may apply an elastic force to the disk in a direction closer to the gas discharge hole.

The first protruding part and the second protruding part may be configured to allow an operation, in which only the rod of the first opening/closing part is pressed, or both the rods of the first opening/closing part and the second opening/closing part are pressed, or pressing of both the rods is released, in response to rotation of the cam.

The flow rate adjuster further may include a driving motor that is coupled to an upper end of the shaft exposed to an outside of the housing and that provides a rotational driving force to the shaft, and the cam may be coupled to a lower end of the shaft, and the blade may be coupled to the shaft to be located between the driving motor and the cam.

The first gas passage may include a main passage that extends downward from the air passage, a first branch passage that extends from one side of the main passage, and a second branch passage that extends from an opposite side of the main passage, and the second gas passage may extend from the first branch passage, and the third gas passage extends from the second branch passage.

The first branch passage and the second branch passage may extend to be located at different heights along an extension direction of the main passage.

The blade may include a body part that is coupled to the shaft, a first wing part that extends from the body part and in which a through-hole having a first extent is formed, and a second wing part that extends from the body part to form a specific angle with the first wing part and in which a through-hole having a second extent that is greater than the first extent is formed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings:

FIG. 1 is a perspective view of a venturi according to an embodiment of the present disclosure;

FIG. 2 is an exploded perspective view of a venturi according to an embodiment of the present disclosure;

FIG. 3 is a cross-sectional perspective view of a venturi according to an embodiment of the present disclosure;

FIG. 4 is a cross-sectional perspective view of a housing of a venturi according to an embodiment of the present disclosure;

FIG. 5 is a horizontal cross-sectional view illustrating an arrangement relationship between a housing of a venturi and a flow rate adjuster according to an embodiment of the present disclosure;

FIGS. 6A, 6B, and 6C are views illustrating an operation of a flow rate adjuster according to an embodiment of the present disclosure;

FIGS. 7A and 7B are cross-sectional views illustrating a first operation mode of a venturi according to an embodiment of the present disclosure;

FIGS. 8A and 8B are cross-sectional views illustrating a second operation mode of a venturi according to an embodiment of the present disclosure; and

FIGS. 9A and 9B are cross-sectional views illustrating a third operation mode of a venturi according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, a venturi according to an embodiment of the present disclosure will be described with reference to the drawings.

A venturi according to an embodiment of the present disclosure is a venturi including a plurality of pipe passages, through which gas and/or air flows, and may be a venturi that is used in a boiler or a combustion apparatus.

FIG. 1 is a perspective view of a venturi according to an embodiment of the present disclosure. FIG. 2 is an exploded perspective view of a venturi according to an embodiment of the present disclosure. FIG. 3 is a cross-sectional perspective view of a venturi according to an embodiment of the present disclosure. FIG. 4 is a cross-sectional perspective view of a housing of a venturi according to an embodiment of the present disclosure. FIG. 5 is a horizontal cross-sectional view illustrating an arrangement relationship between a housing of a venturi and a flow rate adjuster according to an embodiment of the present disclosure.

FIG. 2 illustrates an exploded view of the venturi illustrated in FIG. 1, FIG. 3 illustrates a cross-section of the venturi illustrated in FIG. 1, taken along the x-z plane, FIG. 4 illustrates a cross-section of a housing of the venturi illustrated in FIG. 1, taken along the x-z plane, and FIG. 5 illustrates a cross-section of the venturi illustrated in FIG. 1, taken along the x-y plane.

Meanwhile, the upward/downward direction, the leftward/rightward direction, and the forward/rearward direction mentioned in the present specification are relatively determined based on an arrangement direction of the venturi illustrated in FIG. 1, and hereinafter, descriptions will be provided based on the arrangement direction of the venturi according to FIG. 1 for convenience of description. However, an arrangement direction or an installation direction of the venturi is not limited to a specific direction due to this.

Referring to FIGS. 1 to 5, a venturi 10 according to an embodiment may include a housing 100, an opening/closing part 200, a flow rate adjuster 300, and a nozzle assembly 400.

The housing 100 is a component that forms a main exterior of the venturi 10, and may include a housing body 110 that is provided with a plurality of passages 120 and 130 in an interior thereof, and a guide pipe 150 that is disposed in the interior of the housing body 110 to guide an introduction of air.

The housing body 110 may provide a passage, through which gas and/or air introduced into an interior of the venturi 10 flows. For example, one or more empty spaces may be formed at least at a portion of an interior of the housing body 110, and a plurality of passages 120 and 130 may be defined by the empty spaces.

The plurality of passages 120 and 130 may include an air passage 120, through which air and/or a mixture gas in which air and gas are mixed flows, and a plurality of gas passages 130 that are connected to the air passage 120, and into which gas is introduced to flow. The air passage 120 may communicate with the plurality of gas passages 130 such that gas introduced through the plurality of gas passages 130 may be mixed with air to flow in a partial space of the air passage 120.

The air passage 120 may be opened along a reference direction D. For example, the air passage 120 may be formed to pass through the housing body 110 in a forward/rearward direction (e.g., a direction that is parallel to the y-axis). Here, the reference direction D may be a direction that faces a rear side from a front side based on an arrangement direction of the venturi 10 illustrated in FIGS. 1 and 2, and the reference direction D may be a different direction other than the forward/rearward direction depending on an arrangement direction of the venturi 10. The air passage 120 may include a first opening 123 that functions as an inlet, through which air is introduced, and a second opening 124 that functions as an outlet, through which the mixture gas (e.g., a fluid in which air and gas are mixed) is discharged, and the first opening 123 and the second opening 124 may be connected to an empty space that extends in the forward/rearward direction.

Meanwhile, the air passage 120 is a pipe passage through which air is introduced and air and/or gas mixed with air flows, and does not necessarily mean a pipe passage, through which only air flows.

The plurality of gas passages 130 may include a first gas passage 131 that is connected to the air passage 120, a second gas passage 132 that is connected to one side of the first gas passage 131, and a third gas passage 133 that is connected to an opposite side of the first gas passage 131. For example, the first gas passage 131 may extend downward (e.g., the −z-axis direction) from at least a portion of the air passage 120, the second gas passage 132 may extend leftward (e.g., the −x-axis direction) from at least a portion of the first gas passage 131, and the third gas passage 133 may extend rightward (e.g., the +x-axis direction) from at least a portion of the first gas passage 131.

Gas G introduced from the outside of the venturi 10 into the first gas passage 131 may flow to the air passage 120 connected to the first gas passage 131. Gas G introduced from the outside of the venturi 10 into the second gas passage 132 or the third gas passage 133 may pass through the first gas passage 131 to flow to the air passage 120.

An end of the first gas passage 131 in an upward direction (e.g., the +z-axis direction) may be connected to the air passage 120, and an end of the second sub-passage 132b in a downward direction may be exposed to an outside of the housing body 110 so that an inlet, through which gas is introduced, may be formed.

The first gas passage 131 may include a main passage 131a that extends in an upward/downward direction, a first branch passage 131b that extends from one side of the main passage 131a, and a second branch passage 131c that extends from an opposite side of the main passage 131a. For example, the first branch passage 131b may extend from a left portion of the main passage 131a perpendicularly to the main passage 131a, and the second branch passage 131c may extend from a right portion of the main passage 131a perpendicularly to the main passage 131a. The first branch passage 131b and the second branch passage 131c may be formed at different heights with respect to the upward/downward direction of the main passage 131a. The main passage 131a may communicate the outside of the venturi 10 and the air passage 120, the first branch passage 131b may be connected to the second gas passage 132, and the second branch passage 131c may be connected to the third gas passage 133.

Opening and closing of portions of the second gas passage 132 and the third gas passage 133, which are connected to the first gas passage 131 by the opening/closing part 200, may be adjusted. That is, flow of gas introduced into the second gas passage 132 and the third gas passage 133 toward the first gas passage 131 may be allowed or blocked by an operation of the opening/closing part 200.

Each of the second gas passage 132 and the third gas passage 133 may include a first sub-passage 132a that extends from the first gas passage 131 and in which the opening/closing part 200 is disposed, and a second sub-passage 132b that extends from the first sub-passage 132a to the outside of the housing body 110. For example, the first sub-passage 132a of the second gas passage 132 may extend from the first branch passage 131b of the first gas passage 131 in parallel, and the first sub-passage 132a of the third gas passage 133 may extend from the second branch passage 131c of the first gas passage 131 in parallel. Furthermore, the second sub-passage 132b of each of the second gas passage 132 and the third gas passage 133 may extend downward from at least a portion of the first sub-passage 132a. An end of the second sub-passage 132b in an upward direction may be connected to the first sub-passage 132a, and an end of the second sub-passage 132b in a downward direction may be exposed to an outside of the housing body 110 so that an inlet, through which gas is introduced, may be formed.

The second gas passage 132 and the third gas passage 133 may be located at different heights. For example, as the first branch passage 131b and the second branch passage 131c are formed at different heights, the first sub-passage 132a of the second gas passage 132 and the first sub-passage 132a of the third gas passage 133 may be formed to be spaced apart from each other at a specific interval in the upward/downward direction (e.g., a direction that is parallel to the z axis) while central axes thereof do not overlap each other. According to the illustrated embodiment, the first sub-passage 132a of the second gas passage 132 is located at a lower height than the first sub-passage 132a of the third gas passage 133, and a length of the first sub-passage 132a of the second gas passage 132 in the upward/downward direction is formed to be shorter than that of the first sub-passage 132a of the third gas passage 133, but this is by way of example, and the positions thereof may be interchanged.

Meanwhile, in this way, the second gas passage 132 and the third gas passage 133 are located at different heights as a design for adjusting opening and closing of the opening/closing parts 200 disposed therein with one cam 340, and an amount of supplied gas may be adjusted in three steps by manipulating two opening/closing parts 200 with the one cam 340 by using the height difference.

The guide pipe 150 is a component that guides flow of air introduced into the air passage 120, and may be disposed at a portion (e.g., a front part 121 of the air passage 120) in an interior of the air passage 120, and may extend by a specific length along the forward/rearward direction. For example, the guide pipe 150 may be inserted into an interior of the first opening 123 of the air passage 120 and may extend by a specific length toward the second opening 124.

The guide pipe 150 may have a shape having an empty interior such that air passes therethrough. Air may be introduced into an interior of the air passage 120 through the guide pipe 150, and after passing through the guide pipe 150, may be mixed with the gas introduced into a gas passage 130 and flow through a portion of the air passage 120 located on a rear side of the guide pipe 150.

The guide pipe 150 may include an air inlet hole 153 that is opened toward a front side and through which air is introduced, and an air through-hole 154 that is opened toward a rear side and through which air passes. The guide pipe 150 may be configured to be located between, or at a boundary portion of, a front part 121 and a rear part 122 of the air passage 120. That is, the air introduced into the air inlet hole 153 may flow through the front part 121 along the guide pipe 150, and may pass through the air through-hole 154 to be mixed with gas in the rear part 122 of the air passage 120. For example, the guide pipe 150 may be located in the front part 121 of the air passage 120 to guide introduction of air, and the introduced air may be mixed with gas in the rear part 122 of the air passage 120.

As will be described in detail hereinafter, the venturi 10 of the present disclosure may be configured such that a degree, to which the air through-hole 154 of the guide pipe 150 is opened by the blade 330 of the flow rate adjuster 300, may be adjusted.

The guide pipe 150 may be formed in a shape that becomes narrower as it goes from a front side toward a rear side. The guide pipe 150 may include a coupling part 151 that is coupled to the housing body 110, and an extension part 152 that extends to an interior of the air passage 120. For example, the extension part 152 may have a shape, of which a leftward/rightward width decreases as it goes rearward. The extension part 152 may be formed such that a left surface of the extension part 152 extends in parallel to an inner wall of the air passage 120 and a spacing distance from the inner wall of the air passage 120 increases as a right surface of the extension part 152 goes rearward.

A cutaway part 155 for locating a shaft 310 of the flow rate adjuster 300 may be formed on one side of a rear end of the guide pipe 150. The cutaway part 155 is formed at a rear end of the extension part 152 and is formed to extend in the upward/downward direction from a right portion with respect to a leftward/rightward center, so that a space for locating the shaft 310 may be secured.

According to various embodiments, the guide pipe 150 may be detachably coupled to the housing body 110. Furthermore, according to various embodiments, the guide pipe 150 may be configured to be formed in a form of a partition wall in an interior of the housing body 110 and to be integral with the housing body 110.

The opening/closing part 200 is a component for adjusting a flow rate of gas supplied to the air passage 120, and flow of gas between the first gas passage 131 and the second gas passage 132 and between the first gas passage 131 and the third gas passage 133 may be allowed or blocked.

The opening/closing part 200 may include a first opening/closing part 200a that opens and closes a point between the second gas passage 132 and the first gas passage 131, and a second opening/closing part 200b that opens and closes a point between the third gas passage 133 and the first gas passage 131. The first opening/closing part 200a may be disposed in an interior of the second gas passage 132 and at least a portion thereof may be located in an interior of the first branch passage 131b, and the second opening/closing part 200b may be disposed in an interior of the third gas passage 133 and at least a portion thereof may be located in an interior of the second branch passage 131c.

The first opening/closing part 200a may be disposed in interiors of the first sub-passage 132a of the second gas passage 132 and the first branch passage 131b to open or close a point (that is, a portion, at which the first sub-passage 132a of the second gas passage 132 and the first branch passage 131b are connected to each other) between the first sub-passage 132a of the second gas passage 132 and the first branch passage 131b. Furthermore, the second opening/closing part 200b may be disposed in interiors of the first sub-passage 132a of the third gas passage 133 and the second branch passage 131c to open or close a point (that is, a portion, at which the first sub-passage 132a of the third gas passage 133 and the second branch passage 131c are connected to each other) between the first sub-passage 132a of the third gas passage 133 and the second branch passage 131c.

The first opening/closing part 200a and the second opening/closing part 200b may be the identical assembly having substantially the same components. Hereinafter, the components of the opening/closing part 200 will be described with reference to the first opening/closing part 200a for convenience of description, but this may also be applied to the second opening/closing part 200b in the same way.

The first opening/closing part 200a may include a cylinder 210 that is disposed in an interior of the second gas passage 132, a rod 220, at least a portion of which is inserted into an interior of the cylinder 210 and that is configured to be movable in the leftward/rightward direction by an external force, a disk 230 that is coupled to the rod 220 and opens and closes a gas discharge hole 212 of the cylinder 210, and a spring 240 that is disposed between the disk 230 and the cylinder 210 and generates an elastic force.

The cylinder 210 may be disposed in an interior of the first sub-passage 132a of the second gas passage 132, and may block an opening of the first sub-passage 132a, which is exposed to the outside of the housing body 110. An interior of the cylinder 210 may be in a hollow cylindrical shape, but is not limited thereto. The cylinder 210 may be provided with a communication hole to communicate the first gas passage 131 and the second gas passage 132. The communication hole may include a gas inlet hole 211 that is connected to the second sub-passage 132b of the second gas passage 132 and is configured such that gas is introduced therethrough, and a gas discharge hole 212 that is connected to the first branch passage 131b of the first gas passage 131 and is configured such that gas is discharged therethrough.

The rod 220 is coupled to be linearly moved in an interior of the cylinder 210, and a portion thereof may extend to the outside of the cylinder 210. A portion of the rod 220 that extends to the outside of the cylinder 210 may be located in an interior of the first branch passage 131b of the first gas passage 131, and an external force for linear movement of the rod 220 may be applied.

The disk 230 may be coupled to the rod 220 to be moved together with the rod 220. The disk 230 may adjust flow of the gas provided through the second gas passage 132 by opening or closing the gas discharge hole 212 of the cylinder 210. That is, when a flow rate is insufficient only with the gas introduced into the first gas passage 131, the gas introduced into the second gas passage 132 flows to the first gas passage 131 when the gas discharge hole 212 is opened by the disk 230, and a flow rate of the gas introduced into the air passage 120 increases.

The spring 240 may be disposed between the disk 230 and the cylinder 210 and may apply an elastic force to the disk 230 in a direction that faces the gas discharge hole 212. For example, when an external force is applied to the rod 220 so that the gas discharge hole 212 is opened, and the external force is then removed, the disk 230 and the rod 220 are restored to an original position by an elastic force of the spring 240, and the gas discharge hole 212 is closed.

At least a portion of the flow rate adjuster 300 may be disposed in an interior of the housing 100, and the flow rate adjuster 300 may adjust a flow rate of the air that passes through the air passage 120 and a flow rate of the gas that is supplied to the gas passage 130. The venturi 10 according to the present disclosure may adjust a flow rate of air and a flow rate of gas simultaneously through an operation of the flow rate adjuster 300, and may increase the flow rates in three steps.

The flow rate adjuster 300 may include a shaft 310 that extends in the upward/downward direction and is inserted into an interior of the housing body 110 of the housing 100, a driving motor 320 that is connected to one end of the shaft 310 and applies a rotational force to the shaft 310, a cam 340 that is coupled to an opposite end of the shaft 310 to adjust opening and closing of the opening/closing part 200, and a blade 330 that is coupled to the shaft 310 to adjust an opening degree of the air through-hole 154 provided in the guide pipe 150. The flow rate of air may be adjusted by the blade 330, and the flow rate of gas may be adjusted by the cam 340.

The shaft 310 may be rotatably coupled to the housing body 110. The shaft 310 may extend in the upward/downward direction and may pass through an upper portion of the housing body 110 to be inserted into an interior of the housing body 110. The shaft 310 may be disposed to cross a portion of the air passage 120 in the upward/downward direction so that a lower end thereof is located in the first gas passage 131 (particularly, the main passage 131a). An upper end of the shaft 310 may be exposed to the outside of the housing body 110 and may be coupled to the driving motor 320. The shaft 310 may be substantially perpendicular to an extension direction of the air passage 120.

The shaft 310 may be configured such that a portion thereof is located in a cutaway part 155 provided in the guide pipe 150. For example, the shaft 310 may be disposed to be biased to a right side with respect to a leftward/rightward center of the air through-hole 154, and accordingly, the blade 330 coupled to the shaft 310 is rotated while an existing opening extent of the air through-hole 154 is maximally used, so that an opening degree of the air through-hole 154 is adjusted.

The driving motor 320 may be coupled to an upper end of the shaft 310 to apply a rotational driving force to the shaft 310. The driving motor 320 may be disposed at an upper end of the housing body 110, from which the shaft 310 is exposed, and at least a portion thereof may be coupled to the shaft 310 to rotate the shaft 310. The type of the driving motor 320 is not particularly limited, and may include various types of motors that may provide a rotational force to the shaft 310.

The cam 340 may be coupled to a lower end of the shaft 310 and may be rotated together with the shaft 310. For example, the cam 340 may be rotated integrally with the shaft 310, and a rotation degree of the cam 340 may be substantially the same as a rotation degree of the shaft 310.

The cam 340 may be configured to apply or release a pressing force that faces an interior of the cylinder 210 to the rod 220 of the opening/closing part 200, based on a rotational operation. The cam 340 may include a base part 341, a first protruding part 342 that protrudes from a lower end of the base part 341, and a second protruding part 343 that protrudes from an upper end of the base part 341. For example, the first protruding part 342 may be configured to press the rod 220 of the first opening/closing part 200a, and the second protruding part 343 may be configured to press the rod 220 of the second opening/closing part 200b.

The cam 340 may be configured such that the base part 341 contacts the rod 220, or the protruding parts 342 and 343 contact the rod 220, as it is rotated in response to rotation of the shaft 310. For example, when the base part 341 contacts the rod 220, a pressing force that faces an inside of the cylinder is not applied to the rod 220, and the gas discharge hole 212 remains closed by the disk 230. When the cam 340 is rotated and the protruding parts 342 and 343 contact the rod 220, the rod 220 and the disk 230 are linearly moved to an inside of the cylinder by the protruding parts 342 and 343, and the gas discharge hole 212 is opened. That is, when the protruding parts 342 and 343 contact the cylinder 210, a pressing force that faces an interior of the cylinder 210 is applied to the rod 220.

The first protruding part 342 and the second protruding part 343 may protrude in different directions. The first protruding part 342 and the second protruding part 343 may protrude in a form and an angle, by which an operation of pressing only the rod 220 of the first opening/closing part 200a, an operation of pressing the rods 220 of both the first opening/closing part 200a and the second opening/closing part 200b, and an operation of pressing neither of the rods 220 of the first opening/closing part 200a and the second opening/closing part 200b due to rotation of the cam 340 are possible. That is, as the cam 340 is rotated, a state (e.g., a first operation mode), in which the first opening/closing part 200a and the second opening/closing part 200b are both closed, a state (e.g., a second operation mode), in which only the first opening/closing part 200a is opened, and a state (e.g., a third operation mode), in which the first opening/closing part 200a and the second opening/closing part 200b are both opened, may be implemented.

The blade 330 may be coupled to the shaft 310 to be located between the driving motor 320 and the cam 340, and may be rotated together with the shaft 310. For example, the blade 330 may be rotated integrally with the shaft 310, and a rotation degree of the blade 330 may be substantially the same as a rotation degree of the shaft 310.

The blade 330 may include a body part 331 that is coupled to the shaft 310, a first wing part 332 that extends from the body part 331 and in which one through-hole 334 is formed, and a second wing part 333 that extends from the body part 331 to form a predetermined angle with the first wing part 332 and in which two through-holes 334 are formed.

With respect to a direction that faces a lower side from an upper side (e.g., with respect to an appearance viewed in FIG. 5), the second wing part 333 is provided at a position that is spaced apart from the first wing part 332 counterclockwise by a reference angle a1. For example, the reference angle a1 may be an obtuse angle in correspondence to a tapered shape of the guide pipe 150. In particular, the blade 330 may be configured such that an angle between the first wing part 332 and the second wing part 333, which is measured in an opposite direction to the reference angle a1 (that is, measured clockwise from the first wing part 332), forms an obtuse angle that is greater than the reference angle a1.

The blade 330 adjusts a flow rate of air as the first wing part 332 is located to cover the air through-hole 154, the second wing part 333 is located to cover the air through-hole 154, or the first wing part 332 and the second wing part 333 are located not to cover the air through-hole 154 to completely open the air through-hole 154 as it is rotated together with the shaft 310.

Meanwhile, according to the illustrated embodiment, the first wing part 332 and the second wing part 333 are configured such that a flow rate of air is adjusted while a number of the through-holes 334 varies, but is not limited thereto, and may be configured such that the flow rate of air is adjusted while a size of the through-holes 334 varies. Furthermore, the number of the through-holes 334 formed in the first wing part 332 and the second wing part 333 also is not limited to one or two, and it is sufficient as long as the second wing part 333 has a larger number of the through-holes 334 to increase a flow rate of air as compared with the first wing part 332. That is, the size and/or the number of the through-holes 334 may be variously changed within a range, in which more air may pass through the second wing part 333 than the first wing part 332.

The nozzle assembly 400 may be disposed to cover the gas passage 130 on a lower side of the housing body 110 of the housing 100. The nozzle assembly 400 may include a nozzle 410 and a packing 420.

The nozzle 410 may be disposed to face one surface of the housing body 110, on which a plurality of the gas passages 130 are provided. In the nozzle 410, openings corresponding to the plurality of gas passages 130, respectively, may be formed. For example, in the nozzle 410, openings that are aligned in the upward/downward direction with a lower end opening of the first gas passage 131, a lower end opening of the second gas passage 132, and a lower end opening of the third gas passage 133, respectively, may be formed.

The packing 420 may be disposed between the housing body 110 and the nozzle 410 to seal a space therebetween. For example, the packing 420 may prevent the gas supplied to the gas passage 130 from being discharged to the outside. The packing 420 may be disposed while being compressed between a peripheral portion of the nozzle 410 and the housing body 110, and may have a ring shape that is opened in the upward/downward direction so that the gas that passes through the nozzle 410 may flow to the gas passage 130.

Hereinafter, referring to FIGS. 6A and 6B, an operation of the flow rate adjuster 300 will be described.

FIGS. 6A, 6B, and 6C are views illustrating an operation of a flow rate adjuster according to an embodiment of the present disclosure.

The flow rate adjuster 300 and the guide pipe 150 illustrated in FIGS. 6A, 6B, and 6C are the same as the components of the venturi 10 illustrated in FIGS. 1 to 5, and a repeated description thereof will be omitted hereinafter.

Referring to FIGS. 6A, 6B, and 6C, the flow rate adjuster 300 may adjust a flow rate of air that passes through the guide pipe 150 and a flow rate of gas that is introduced through the opening/closing part 200 in three steps. Specifically, the flow rate adjuster 300 may be configured to increase or decrease a flow rate of air and a flow rate of gas in steps while the blade 330 and the cam 340 are rotated together in response to rotation of the shaft 310. For example, when operated in the order of FIGS. 6A, 6B, and 6C, a flow rate of air and gas may be increased step by step, and conversely, when operated in the order of FIGS. 6C, 6B, and 6A, a flow rate of air and gas may be decreased step by step.

First, as illustrated in FIG. 6A, the first wing part 332, in which one through-hole 334 is provided, covers the air through-hole 154 of the guide pipe 150, and the base part 341 of the cam 340 contacts the rods 220 of the first opening/closing part 200a and the second opening/closing part 200b.

Subsequently, as illustrated in FIG. 6B, as the shaft 310 is rotated clockwise at a specific angle, the blade 330 and the cam 340 are rotated at the same angle, and the second wing part 333 provided with two through-holes 334 covers the air through-hole 154 of the guide pipe 150, and the first protruding part 342 of the cam 340 contacts the rod 220 of the first opening/closing part 200a to press the rod 220 to an inside of the cylinder 210.

Subsequently, as illustrated in FIG. 6C, as the shaft 310 is additionally rotated clockwise at a specific angle, the blade 330 and the cam 340 are additionally rotated at the same angle, and the first wing part 332 and the second wing part 333 are moved to a position, in which they do not overlap the air through-hole 154, to completely open the air through-hole 154, and the second protruding part 343 of the cam 340 contacts the rod 220 of the second opening/closing part 200b to press the rod 220 to an inside of the cylinder 210. In this case, a state, in which the first protruding part 342 of the cam 340 presses the rod 220 of the first opening/closing part 200a, is maintained.

That is, as described above, the cam 340 may have a shape in which the first protruding part 342 and the second protruding part 343 protrude from upper and lower ends of the base part 341 in different directions such that an operation of pressing neither of the rods 220 of the first opening/closing part 200a and the second opening/closing part 200b, an operation of pressing only the rod 220 of the first opening/closing part 200a, and an operation of pressing both of the rods 220 of the first opening/closing part 200a and the second opening/closing part 200b are possible as the shaft 310 is rotated.

FIGS. 7A and 7B are cross-sectional views illustrating a first operation mode of a venturi according to an embodiment of the present disclosure. FIGS. 8A and 8B are cross-sectional views illustrating a second operation mode of a venturi according to an embodiment of the present disclosure. FIGS. 9A and 9B are cross-sectional views illustrating a third operation mode of a venturi according to an embodiment of the present disclosure.

FIGS. 7A, 8A, and 9A illustrate cross-sections of the venturi 10, taken along the x-z plane, in the operation modes, and FIGS. 7B, 8B, and 9B illustrate cross-sections of the venturi 10, taken along the x-y plane, in the operation modes.

FIGS. 7A to 9B are diagrams for explaining the three-step operation modes of the venturi 10 illustrated in FIGS. 1 to 5, and a repeated description thereof will be omitted hereinafter.

Referring to FIGS. 7A to 9B, the venturi 10 according to an embodiment may operate in a first operation mode, a second operation mode, in which a flow rate of air and gas is increased compared to the first operation mode, and a third operation mode, in which a flow rate of air and gas is increased compared to the second operation mode, in response to driving of the flow rate adjuster 300.

Meanwhile, in the first operation mode, an operation state of the flow rate adjuster 300 may be referenced in the form illustrated in FIG. 6A, in the second operation mode, an operation state of the flow rate adjuster 300 may be referenced in the form illustrated in FIG. 6B, and in the third operation mode, an operation state of the flow rate adjuster 300 may be referenced in the form illustrated in FIG. 6C.

First, as illustrated in FIGS. 7A and 7B, in the first operation mode, the first wing part 332 is located in the air through-hole 154 of the guide pipe 150 so that an opening degree of the air through-hole 154 may be smaller than those of the second operation mode and the third operation mode. The air A introduced into the guide pipe 150 flows to a rear part of the air passage 120 through the one through-hole 334 provided in the first wing part 332 to be mixed with the gas. In this case, the first opening/closing part 200a and the second opening/closing part 200b are in a state, in which the gas discharge hole 212 is closed by the disk 230, and the gas G1 may be supplied to the air passage 120 through the first gas passage 131. That is, in the first operation mode, supply of the gas through the second gas passage 132 and the third gas passage 133 is blocked.

Subsequently, as illustrated in FIGS. 8A and 8B, in the second operation mode, the second wing part 333 is located in the air through-hole 154 of the guide pipe 150 so that an opening degree of the air through-hole 154 may be greater than that of the first operation mode and smaller than that of the third operation mode. The air A introduced into the guide pipe 150 flows to a rear part of the air passage 120 through the two through-holes 334 provided in the second wing part 333 to be mixed with the gas. In this case, the second opening/closing part 200b is maintained in a state, in which the gas discharge hole 212 is closed by the disk 230, but the first opening/closing part 200a is in a state, in which the rod 220 and the disk 230 are moved leftward by the cam 340 so that the gas discharge hole 212 is opened. Accordingly, the gases G1 and G2 may be supplied to the air passage 120 through the first gas passage 131 and the second gas passage 132. The gas G2 supplied through the second gas passage 132 passes through the gas inlet hole 211 and the gas discharge hole 212 of the first opening/closing part 200a to flow to the air passage 120. That is, in the second operation mode, supply of the gas through the second gas passage 132 is additionally allowed, and supply of the gas through the third gas passage 133 is blocked.

Finally, as illustrated in FIGS. 9A and 9B, in the third operation mode, the air through-hole 154 of the guide pipe 150 is completely opened so that an opening degree of the air through-hole 154 may be greater than those of the first operation mode and the second operation mode. The air A introduced into the guide pipe 150 flows to a rear part of the air passage 120 through an entire area of the air through-hole 154 to be mixed with the gas. In this case, the first opening/closing part 200a maintains a state, in which the gas discharge hole 212 is opened, and the second opening/closing part 200b is in a state, in which the rod 220 and the disk 230 are moved rightward by the cam 340 so that the gas discharge hole 212 is opened. Accordingly, the gases G1, G2, and G3 may be supplied to the air passage 120 through the first gas passage 131, the second gas passage 132, and the third gas passage 133. Like the gas G2 supplied through the second gas passage 132, the gas G3 supplied through the third gas passage 133 passes through the gas inlet hole 211 and the gas discharge hole 212 of the second opening/closing part 200b to flow to the air passage 120. That is, in the third operation mode, supply of the gas through the second gas passage 132 and the third gas passage 133 is additionally allowed.

As described above, the venturi 10 according to the present disclosure may improve a turndown ratio (TDR) by adjusting a flow rate of air and gas in three steps.

According to the present disclosure, since a flow rate of air and gas may be adjusted in three steps, a turndown ratio (TDR) may be improved to enhance a performance of a boiler.

Although the present disclosure has been described above by means of limited embodiments and drawings, the present disclosure is not limited thereto, and various embodiments are possible within the scope that is equivalent to the technical idea of the present disclosure and the scope of the patent claims to be described below by a person skilled in the art, to which the present disclosure pertains.