Air-liquid mixing device

Abstract

To provide a gas-liquid mixing device (100) by which workability in assembling or maintenance can be secured even when mounted in a narrow place.SOLUTION: A venturi passage (131) is formed inside a venturi member (130); a cover member (120) is attached to an outside surface of the venturi member; and an air chamber (137) is formed between the outside surface of the venturi member and the cover member. Air absorbed from an air passage (131d) into the venturi passage is supplied from an air inflow port (127) formed on the cover member via the air chamber, and an electromagnetic opening / closing valve (110) that opens / closes the air inflow port is attached to the air inflow port. Thus, the position of the air inflow port is moved, and the position of the electromagnetic opening / closing valve can be moved within a range open in the air chamber. Therefore, a gap between the electromagnetic opening / closing valve and other components is secured, and workability in assembling or maintenance can be secured.SELECTED DRAWING: Figure 1

Description

Technical Field

[0004] , , , , , ,

[0001] The present invention relates to a gas-liquid mixing device that generates an air-mixed liquid in which air is mixed in a liquid by allowing air to flow into the liquid passing through a Venturi passage from the minimum inner diameter portion of the Venturi passage.

Background Art

[0002] When the flow of a liquid is guided into a Venturi passage, it is known that at the minimum inner diameter portion where the inner diameter of the Venturi passage is the smallest, the flow velocity of the liquid increases and the pressure of the liquid decreases. Therefore, a gas-liquid mixing device has been proposed in which an air passage is opened at the minimum inner diameter portion of the Venturi passage, the liquid is passed through the Venturi passage, and air is sucked in by the negative pressure generated at the minimum inner diameter portion to mix air into the liquid (Patent Document 1).

[0003] Here, the Venturi passage has a shape in which a portion where the inner diameter of the passage increases downstream (hereinafter referred to as an expanding passage portion) is connected to the downstream side of a portion where the inner diameter of the passage decreases downstream (hereinafter referred to as a reducing passage portion). For this reason, it is difficult to manufacture the Venturi passage of the gas-liquid mixing device by methods such as machining or sheet metal working, and it is usually formed by integral molding by die casting using materials such as resin or aluminum. Also, the air passage that opens at the minimum inner diameter portion of the Venturi passage is formed by integral molding or additional processing. And an electromagnetic on-off valve is attached to the inlet portion of the air passage, and by opening and closing the electromagnetic on-off valve, air is mixed into the liquid or the mixing of air is stopped.

Prior Art Documents

Patent Documents

[0005] However, the gas-liquid mixing device with the structure described above had a problem in that it was difficult to ensure sufficient workability during assembly and maintenance when it was to be installed in a confined space, such as inside a water heater. The reason for this is as follows:

[0006] First, because the venturi passage has a shape in which an enlarged passage is connected downstream of a reduced-diameter passage, the overall length of the gas-liquid mixing device becomes long, limiting the mounting position and direction when trying to install it in a narrow space. In addition, the gas-liquid mixing device has an air passage formed from the side of the venturi passage, opening into the smallest inner diameter of the venturi passage, and an electromagnetic valve is attached to the inlet of this air passage. Therefore, when trying to install the gas-liquid mixing device in a narrow space, it often becomes difficult to secure sufficient space between the electromagnetic valve and other components (such as piping). Even if one tries to move the position of the electromagnetic valve attached to the gas-liquid mixing device in order to secure space, the position of the electromagnetic valve is almost entirely determined by the position of the smallest inner diameter of the venturi passage formed inside the gas-liquid mixing device. Therefore, in order to move the position of the electromagnetic valve, it becomes necessary to move the position or direction of the gas-liquid mixing device, but when trying to install the gas-liquid mixing device in a narrow space, it is difficult to move the position or direction of the gas-liquid mixing device. For these reasons, attempting to install a gas-liquid mixing device with a venturi passage in a confined space sometimes made it difficult to ensure sufficient workability during assembly and maintenance.

[0007] This invention was made to solve the aforementioned problems of the conventional technology, and aims to provide a gas-liquid mixing device that ensures workability during assembly and maintenance, even when installed in a confined space. [Means for solving the problem]

[0008] To solve the above-mentioned problems, the gas-liquid mixing apparatus of the present invention employs the following configuration: A gas-liquid mixing device comprising a venturi passage whose inner diameter narrows downstream and then widens, and an air passage opening at the minimum inner diameter portion of the passage where the inner diameter is smallest, wherein air is mixed from the air passage into the liquid flowing in from the inlet of the venturi passage and passing through the minimum inner diameter portion, and the resulting air-mixed liquid is discharged from the outlet of the venturi passage, The aforementioned venturi passage is formed inside the venturi member, The air passage is opened on the outer surface of the venturi member in the direction laterally to the venturi passage, and a cover member is attached so as to cover at least the portion where the air passage is open, thereby forming an air chamber between the outer surface of the venturi member and the cover member. The cover member is provided with an air inlet for allowing air to flow into the air chamber, and an electromagnetic valve for opening and closing the air inlet is attached to the air inlet. It is characterized by the following:

[0009] In the gas-liquid mixing apparatus of the present invention, when liquid is passed through the venturi passage, a negative pressure is generated at the smallest inner diameter of the venturi passage, and air is drawn in through an air passage opening at the smallest inner diameter, thereby mixing air into the liquid. Here, the venturi passage is formed inside the venturi member, and a cover member is attached to the outer surface of the venturi member, so that an air chamber is formed between the outer surface of the venturi member and the cover member. The air drawn into the venturi passage from the air passage is supplied from this air chamber, and air is supplied to the air chamber from an air inlet formed in the cover member. An electromagnetic valve for opening and closing the air inlet is attached to the air inlet.

[0010] This allows the position of the air inlet to be moved as long as it is within the range of opening to the air chamber, and consequently, the position of the electromagnetic valve can also be moved. Therefore, even when attempting to install a gas-liquid mixing device in a confined space and it is not possible to secure sufficient space between the electromagnetic valve and other components, sufficient space can be secured by moving the position of the electromagnetic valve, and as a result, sufficient workability during assembly and maintenance can be ensured.

[0011] Furthermore, in the gas-liquid mixing apparatus of the present invention described above, the air chamber may be formed as follows. First, the outer surface of the venturi member is formed such that the inlet side outer surface on the side where the inlet is formed and the outlet side outer surface on the side where the outlet is formed are cylindrical, and the intermediate outer surface between the inlet side outer surface and the outlet side outer surface is formed to have a smaller diameter than the inlet side outer surface and the outlet side outer surface. The smallest inner diameter portion of the venturi passage is formed on the inside of the intermediate outer surface. Then, the air chamber may be formed by covering the entire circumference of the intermediate outer surface of the venturi member with a hollow cylindrical cover member.

[0012] This allows the air chamber to be shaped so that it surrounds the venturi member in the circumferential direction at the intermediate outer surface. As a result, the air intake of the cover member can be formed at any position in the circumferential direction, and the position of the electromagnetic valve can also be moved freely. In addition, since the air chamber is formed at the intermediate outer surface where the outer diameter of the venturi member is reduced, the outer diameter of the cover member can be reduced, which prevents the gas-liquid mixing device from becoming too large.

[0013] Furthermore, in the gas-liquid mixing device of the present invention described above, multiple air inlets may be formed in the cover member, and one of these air inlets may be selected to be fitted with an electromagnetic valve.

[0014] By doing so, by selecting an appropriate air inlet among the plurality of air inlets formed at multiple locations, the position of the electromagnetic on-off valve can be moved without changing the cover member. Incidentally, for the remaining air inlets that are not selected, a sealing plate may be attached instead of the electromagnetic on-off valve.

Brief Description of the Drawings

[0015] [Figure 1] It is an exploded assembly view of the gas-liquid mixing device 100 of the present embodiment. [Figure 2] It is an explanatory view showing the overall shape and operation of the gas-liquid mixing device 100 of the present embodiment. [Figure 3] It is a block diagram showing a rough structure of the water heater 1 equipped with the gas-liquid mixing device 100 of the present embodiment. [ [Figure 4] It is an explanatory view of a conventional gas-liquid mixing device 900. [Figure 5] It is an explanatory view showing the internal structure of the gas-liquid mixing device 100 of the present embodiment. [Figure 6] It is an explanatory view showing the reason why the position of the solenoid valve assembly 110 of the gas-liquid mixing device 100 of the present embodiment can be easily changed. [Figure 7] It is an explanatory view of the gas-liquid mixing device 100 of the first modification example. [Figure 8] It is an explanatory view of the gas-liquid mixing device 100 of the second modification example. [Figure 9] It is an explanatory view of the gas-liquid mixing device 100 of the third modification example.[ [Figure 10] It is an explanatory view showing the internal structure of the gas-liquid mixing device 100 of the third modification example. [Figure 11] It is an explanatory view showing the reason why the position of the solenoid valve assembly 110 of the gas-liquid mixing device 100 of the third modification example can be easily changed. [Figure 12] It is an explanatory view of the gas-liquid mixing device 100 of the fourth modification example.

Modes for Carrying Out the Invention

[0016] A. This embodiment: FIG. 1 is an exploded assembly view of the gas-liquid mixing device 100 of the present embodiment. The gas-liquid mixing device 100 of the present embodiment has a structure in which a solenoid valve assembly 110, a main body pipe 120, and a Venturi pipe 130 are combined. The Venturi pipe 130 is a hollow member in which a Venturi passage 131 is formed inside. An inlet 132 is formed by the opening of the Venturi passage 131 at one end side of the Venturi pipe 130, and an outlet 133 is formed by the opening of the Venturi passage 131 at the other end side of the Venturi pipe 130.

[0017] The inner diameter of the Venturi passage 131 is constant near the inlet 132, but gradually decreases from the middle towards the downstream (the direction of the outlet 133), and the inner diameter of the passage becomes the smallest. After that, after the inner diameter of the passage is maintained at the minimum for a predetermined distance, the inner diameter of the passage gradually increases towards the downstream, and finally reaches the outlet 133. Hereinafter, the portion where the inner diameter of the Venturi passage 131 is the smallest is referred to as the minimum inner diameter portion 131b, the portion upstream of the minimum inner diameter portion 131b is referred to as the reduced diameter passage portion 131a, and the portion downstream of the minimum inner diameter portion 131b is referred to as the enlarged diameter passage portion 131c.

[0018] The shape of the outer surface of the Venturi pipe 130 is cylindrical at both ends (that is, the side of the inlet 132 and the side of the outlet 133), and between these two cylindrical sides, it is conical with a smaller diameter than the cylindrical shape. Hereinafter, the cylindrical outer surface formed on the side of the inlet 132 is referred to as the "inlet side outer surface 134a", the cylindrical outer surface formed on the side of the outlet 133 is referred to as the "outlet side outer surface 134c", and the conical outer surface between the inlet side outer surface 134a and the outlet side outer surface 134c is referred to as the "intermediate outer surface 134b".

[0019] The inlet-side outer surface 134a and the outlet-side outer surface 134c have the same diameter, but the outer diameter of the intermediate outer surface 134b is smaller on the inlet-side outer surface 134a side and increases as it approaches the outlet-side outer surface 134c. Furthermore, the inlet-side outer surface 134a is formed in a range corresponding to the outside of the reduced-diameter passage portion 131a of the Venturi passage 131, the intermediate outer surface 134b is formed in a range corresponding to the outside of the minimum inner diameter portion 131b of the Venturi passage 131 and the outside of the majority of the enlarged-diameter passage portion 131c that continues from the minimum inner diameter portion 131b, and the outlet-side outer surface 134c is formed in a range corresponding to the outside of the remaining portion of the enlarged-diameter passage portion 131c. In addition, an air passage 131d is formed from the intermediate outer surface 134b, penetrating into the minimum inner diameter portion 131b of the Venturi passage 131.

[0020] Furthermore, on the upstream side (closer to the inlet 132) of the inlet-side outer surface 134a, two mounting protrusions 136 are provided, symmetrically with respect to the central axis of the inlet-side outer surface 134a, and mounting holes 136a are formed in each mounting protrusion 136. These two mounting protrusions 136 are used to attach the venturi tube 130 to the main tube 120, which will be described later. In addition, O-rings 135 made of a heat-resistant rubber material such as silicone rubber are attached to the inlet-side outer surface 134a and the outlet-side outer surface 134c. Note that the venturi tube 130 in this embodiment corresponds to the "venturi member" in the present invention.

[0021] The main pipe 120 has a cylindrical body portion 121 in which an internal passage 121a is formed, and a cylindrical discharge portion 122, which is shorter and has a smaller diameter than the main body portion 121, is projected from the side of the body portion 121. The inner diameter of the internal passage 121a is set to a size that allows the Venturi tube 130 to be inserted, and an insertion port 123 is formed at the end face of the main body portion 121 by the opening of the internal passage 121a. When the Venturi tube 130 is inserted into the internal passage 121a from the insertion port 123, the O-rings 135 attached to the inlet side outer surface 134a and the O-rings 135 attached to the outlet side outer surface 134c of the Venturi tube 130 are pressed against the inner circumferential surface 121b of the internal passage 121a. As a result, an airtight space (air chamber 137 shown in Figure 5) is formed at the gap between the intermediate outer surface 134b of the Venturi tube 130 and the internal passage 121a of the main body portion 121.

[0022] Furthermore, mounting protrusions 125 are provided on both sides of the insertion opening 123, extending outward, and mounting holes 125a are formed in each mounting protrusion 125. The positions of these mounting protrusions 125 and mounting holes 125a are such that when the Venturi tube 130 is inserted through the insertion opening 123, they overlap with the mounting protrusions 136 and mounting holes 136a provided on both sides of the Venturi tube 130. Therefore, after inserting the Venturi tube 130 into the internal passage 121a from the insertion opening 123 of the main body 121 and aligning the positions of the mounting holes 125a of the mounting protrusions 125 and the mounting holes 136a of the mounting protrusions 136, the Venturi tube 130 can be assembled to the main body tube 120 using nuts (not shown) by inserting screws (not shown) through the mounting holes 125a and 136a.

[0023] Furthermore, the internal passage 121a of the main body 121 has a smaller inner diameter in the portion facing the back when viewed from the side of the insertion opening 123, and the internal passage 121a is closed further back. The internal passage 122a of the discharge section 122 is connected to the portion of the internal passage 121a where the inner diameter is smaller from the side. Moreover, the other end of the internal passage 122a opens to the lower end surface of the discharge section 122, forming a discharge port 124.

[0024] A mounting portion 126 for attaching the solenoid valve assembly 110 is provided protruding from the outer surface of the main body portion 121. A flat mounting surface 126a is formed on the upper surface of the mounting portion 126, and an air inlet 127 communicating with the internal passage 121a of the main body portion 121 is formed in the center of the mounting surface 126a. In this embodiment, the main body pipe 120 corresponds to the "cover member" in the present invention.

[0025] The solenoid valve assembly 110 has a structure in which two solenoid valves 112 and a filter 113 are attached to a body portion 111 molded from hard resin. A flange surface 111a is formed on the bottom side of the body portion 111, and a short cylindrical insertion portion 111b protrudes from the center of the flange surface 111a, with an O-ring 111c attached to the outer surface of the insertion portion 111b. An introduction passage (not shown) is formed inside the body portion 111, with one end of the introduction passage opening into the center of the insertion portion 111b, and the other end of the introduction passage connected to the filter 113. The two solenoid valves 112 can open and close the introduction passage at their respective positions.

[0026] Furthermore, the outer diameter of the insertion portion 111b of the solenoid valve assembly 110 is set to a size that allows it to be inserted into the air inlet 127 that opens on the mounting surface 126a of the main pipe 120. With the insertion portion 111b inserted into the air inlet 127, the body portion 111 can be screwed to the mounting portion 126 using the mounting screw 114, thereby allowing the solenoid valve assembly 110 to be assembled to the main pipe 120. In this embodiment, the entire solenoid valve assembly 110 corresponds to the "electromagnetic on / off valve" in the present invention.

[0027] As shown in Figure 2, the gas-liquid mixing device 100 of this embodiment, having the structure described above, draws in air from the filter 113 and mixes it with the liquid simply by supplying liquid from the inlet 132. Therefore, it is possible to discharge liquid mixed with air from the outlet 124. For this reason, if the gas-liquid mixing device 100 is incorporated into the piping of a water heater, for example, it becomes possible to supply hot water mixed with air.

[0028] Figure 3 illustrates a case in which the gas-liquid mixing device 100 of this embodiment is incorporated into a water heater 1 equipped with a bath reheating function. The water heater 1 has a structure in which a combustion canister 10 is mounted inside the main body case 2. The combustion canister 10 is divided into a main combustion canister 10a for hot water supply and a secondary combustion canister 10b for reheating the bath. The main combustion canister 10a houses a main burner 12 and a main heat exchanger 13 for hot water supply, and the secondary combustion canister 10b houses a secondary burner 15 and a secondary heat exchanger 16 for reheating. Furthermore, a combustion fan 14 is attached to the bottom of the combustion canister 10, and when the combustion fan 14 is rotated, air is supplied to the main combustion canister 10a and the secondary combustion canister 10b.

[0029] The fuel gas to be burned in the main burner 12 and the auxiliary burner 15 is supplied from the gas piping 20, which is equipped with a main gas solenoid valve 21 and a gas proportional valve 22. The gas piping 20 branches downstream of the gas proportional valve 22; one branch of the gas piping 20 is connected to the main burner 12 via the main gas solenoid valve 23, and the other branch of the gas piping 20 is connected to the auxiliary burner 15 via the auxiliary gas solenoid valve 24. When the main gas solenoid valve 21 is opened, fuel gas is supplied to the main gas solenoid valve 23 and the auxiliary gas solenoid valve 24. When the main gas solenoid valve 23 is opened in this state, fuel gas is supplied to the main burner 12, and when the auxiliary gas solenoid valve 24 is opened, fuel gas is supplied to the auxiliary burner 15. Furthermore, the flow rate of the fuel gas can be adjusted by adjusting the opening degree of the gas proportional valve 22. Then, while the combustion fan 14 is rotating, a spark is generated from a spark plug (not shown) to ignite the fuel gas supplied to the main burner 12 or the sub-burner 15, and combustion begins in the main burner 12 or the sub-burner 15.

[0030] Furthermore, a main heat exchanger 13 is mounted above the main burner 12, and a secondary heat exchanger 16 is mounted above the secondary burner 15. The main heat exchanger 13 and the secondary heat exchanger 16 have a shape in which a meandering hollow copper pipe passes through multiple copper heat absorption plates. A water supply pipe 25 is connected to one end of the hollow pipe of the main heat exchanger 13, and a hot water supply pipe 30 is connected to the other end of the hollow pipe of the main heat exchanger 13. In addition, a bath supply pipe 51 is connected to one end of the hollow pipe of the secondary heat exchanger 16, and a bath return pipe 52 is connected to the other end of the hollow pipe of the secondary heat exchanger 16. Furthermore, a main valve 27 is mounted in the middle of the water supply pipe 25, a water filter 28 is mounted downstream of the main valve 27, and a flow sensor 26 is mounted downstream of the water filter 28.

[0031] When the hot water tap 3 attached to the end of the hot water pipe 30 is opened, the hot water (or water) inside the hot water pipe 30 flows out from the hot water tap 3, and the amount of water that flows out is supplied to the main heat exchanger 13 from the water supply pipe 25. When the flow sensor 26 detects this water flow, the combustion fan 14 is rotated to start supplying combustion air to the main burner 12, and the main gas solenoid valve 23 is opened while a spark is emitted from a spark plug (not shown), thereby starting the combustion of fuel gas in the main burner 12. The combustion exhaust generated by the combustion passes between the heat absorption plates of the main heat exchanger 13 mounted above the main burner 12, and at this time the water passing inside the hollow pipe of the main heat exchanger 13 is heated, generating hot water. The hot water thus generated flows out from the hot water tap 3 through the hot water pipe 30.

[0032] Furthermore, the bath supply pipe 51 connected to one end of the hollow pipe of the auxiliary heat exchanger 16 is connected to the circulation fitting 5 of the bathtub 4, and the bath return pipe 52 connected to the other end of the hollow pipe of the auxiliary heat exchanger 16 is also connected to the circulation fitting 5 of the bathtub 4. A circulation pump 54 is installed in the middle of the bath return pipe 52, and a water flow switch 55 is installed in the bath return pipe 52 between the circulation pump 54 and the auxiliary heat exchanger 16. In addition, a hot water filling pipe 33, which is branched from the hot water supply pipe 30, is connected to the bath return pipe 52 between the circulation fitting 5 and the circulation pump 54. A hot water filling solenoid valve 34, a check valve 35, and a flow meter 36 are installed in this hot water filling pipe 33. Furthermore, a water temperature sensor 56 is attached to the bath return pipe 52.

[0033] When filling the bathtub 4 with hot water, the circulation pump 54 is stopped, and the hot water filling solenoid valve 34 is opened. Then, the hot water in the hot water supply pipe 30 flows through the hot water filling pipe 33 into the bath return pipe 52, and then flows into the bathtub 4 from the circulation fitting 5 through the bath return pipe 52. Also, since the circulation pump 54 is stopped, some of the hot water that flows from the hot water filling pipe 33 into the bath return pipe 52 passes through the circulation pump 54, then through the bath return pipe 52, the auxiliary heat exchanger 16, and the bath supply pipe 51, and flows into the bathtub 4 from the circulation fitting 5. The amount of hot water supplied to the bathtub 4 is measured by the flow meter 36, and when the amount of hot water reaches a predetermined amount, the hot water filling solenoid valve 34 is closed to end the filling process.

[0034] To reheat the water in the bathtub 4, the circulation pump 54 is activated. The water in the bathtub 4 is then drawn into the circulation pump 54 via the circulation fitting 5 and the bath return pipe 52, and is pumped from the circulation pump 54 to the auxiliary heat exchanger 16. After passing through the auxiliary heat exchanger 16, the water is returned to the bathtub 4 via the bath supply pipe 51 and the circulation fitting 5. When a circulating flow of water is created in the bathtub 4 in this way, the water flow switch 55 detects the flow, and the water temperature sensor 56 detects the water temperature. If the water flow switch 55 detects the flow and the water temperature detected by the water temperature sensor 56 is below a predetermined temperature, reheating is started by burning fuel gas in the auxiliary burner 15. The combustion of fuel gas in the auxiliary burner 15 is started by activating the combustion fan 14 and opening the auxiliary gas solenoid valve 24 while a spark is generated from a spark plug (not shown).

[0035] Furthermore, as shown in Figure 3, the gas-liquid mixing device 100 in this embodiment is mounted in the middle of the bath return piping 52 that connects the circulation pump 54 and the auxiliary heat exchanger 16. Therefore, when hot water is pumped from the circulation pump 54 toward the auxiliary heat exchanger 16, air is mixed into the hot water by the gas-liquid mixing device 100, making it possible to discharge hot water mixed with air into the bathtub 4.

[0036] However, the water heater 1 houses a combustion fan 14, a main gas solenoid valve 23, a secondary gas solenoid valve 24, a gas proportional valve 22, a main gas solenoid valve 21, and gas piping 20 for connecting these components in the narrow space below the combustion tank 10. Furthermore, the water supply piping 25 and hot water supply piping 30 connected to the main heat exchanger 13, the main valve 27 mounted on the water supply piping 25, the water filter 28, the hot water filling piping 33 branched from the hot water supply piping 30, the hot water filling solenoid valve 34 mounted in the middle of the hot water filling piping 33, the check valve 35, and the flow meter 36, all of which are housed in the narrow space below the combustion tank 10. In addition, the bath supply piping 51 and bath return piping 52 connected to the secondary heat exchanger 16, the circulation pump 54 mounted in the middle of the bath return piping 52, the water flow switch 55, and the water temperature sensor 56, all of which are housed in the narrow space below the combustion tank 10. It is not easy to house a gas-liquid mixing device in a narrow space that already contains various pipes and equipment, and even if it can be housed, it is difficult to ensure ease of assembly and maintenance. However, the gas-liquid mixing device 100 of this embodiment makes it possible to ensure sufficient ease of assembly and maintenance even when installed in such a narrow space. Below, as preparation for explaining the reason for this, an overview of conventional gas-liquid mixing devices will be given.

[0037] Figure 4 is an explanatory diagram illustrating the overview of a conventional gas-liquid mixing device 900. Figure 4(a) shows the external shape, and Figure 4(b) shows the internal structure. As shown in Figure 4(a), the conventional gas-liquid mixing device 900 has a cylindrical venturi tube 920 with a venturi passage 921 formed inside, and a solenoid valve assembly 910 attached to the side of the venturi tube 920. An inlet 924 is formed at one end of the venturi tube 920 by opening the venturi passage 921. A flange 922 is formed at the other end of the venturi tube 920, and a sealing plate 923 is attached to the flange 922 with screws 923a. Therefore, the far side of the venturi passage 921 (i.e., the side opposite the inlet 924) is closed, but a cylindrical discharge section 925 is connected to the venturi pipe 920 from the side, and the internal passage 925a of the discharge section 925 is connected to the venturi passage 921 from the side. An outlet 926 is opened at the lower end of the discharge section 925. Note that the solenoid valve assembly 910 is the same as the solenoid valve assembly 110 described above using Figure 1, so its explanation is omitted.

[0038] Figure 4(b) shows a cross-sectional view of the Venturi tube 920 when it is cut at a point passing through the central axis of the Venturi passage 921. As shown in the figure, the Venturi passage 921 of the conventional gas-liquid mixing device 900 also has a reduced-diameter passage section 921a, a minimum inner diameter section 921b, and an expanded-diameter passage section 921c, and furthermore, an air passage 921d opens at the position of the minimum inner diameter section 921b. Since this air passage 921d is formed perpendicular to the minimum inner diameter section 921b, the position where the air passage 921d opens on the outer surface of the Venturi tube 920 is directly lateral to the minimum inner diameter section 921b. Therefore, the position where the solenoid valve assembly 910 is attached to the outer surface of the Venturi tube 920 is also directly lateral to the minimum inner diameter section 921b.

[0039] Furthermore, since the inner diameter of the Venturi passage 921 increases from the minimum inner diameter section 921b to both sides, openings are required at both ends of the Venturi tube 920 when forming it. That is, for example, when forming the reduced-diameter passage section 921a, an opening 921e is required for removing the mold if it is formed using a mold, or an opening 921e is required for inserting the cutting tool if it is formed by cutting. Similarly, when forming the enlarged-diameter passage section 921c, an opening 921f is required for removing the mold (for inserting the cutting tool). Of these two openings 921e and 921f, opening 921e can be used as the inlet 924 of the Venturi passage 921, but opening 921f must be sealed with a sealing plate 923 (unless it can be used as the outlet of the Venturi passage 921). This necessitates providing a flange 922 at the end of the Venturi tube 920 to attach the sealing plate 923. The Venturi tube 920 is already long because it has a Venturi passage 921 formed inside, but since a flange 922 must be provided at the end of the tube and a sealing plate 923 must be attached, the overall length of the Venturi tube 920 becomes even longer.

[0040] If such a conventional gas-liquid mixing device 900 is to be installed in the narrow space of, for example, a water heater 1, the installation position and direction will be severely restricted. Moreover, since a large solenoid valve assembly 910 is attached to the side of the venturi pipe 920, the solenoid valve assembly 910 may come too close to other parts and piping inside the water heater 1. Therefore, even if the position of the solenoid valve assembly 910 is moved to ensure clearance between the solenoid valve assembly 910 and other parts and piping, the solenoid valve assembly 910 must be installed to the side of the smallest inner diameter portion 921b of the venturi passage 921, so the position of the gas-liquid mixing device 900 itself must be moved. However, since the space in which the gas-liquid mixing device 900 is installed is narrow, it is not easy to move the position of the long gas-liquid mixing device 900. As a result, with conventional gas-liquid mixing devices 900, it may be difficult to ensure workability during assembly and maintenance. In contrast, the gas-liquid mixing device 100 of this embodiment makes it easy to ensure workability during assembly and maintenance for the following reasons.

[0041] Figure 5 is a cross-sectional view showing the internal structure of the gas-liquid mixing device 100 of this embodiment. As described above using Figure 1, the gas-liquid mixing device 100 of this embodiment has a structure in which a Venturi tube 130 is inserted into the internal passage 121a of the main pipe 120, and the shape of the outer surface of the Venturi tube 130 is such that the central intermediate outer surface 134b is narrower than the inlet side outer surface 134a and the outlet side outer surface 134c on both sides (see Figure 1). Therefore, as shown in Figure 5, an air chamber 137 is formed between the intermediate outer surface 134b and the internal passage 121a, with both sides airtightly sealed by O-rings 135. An air passage 131d is formed from the wall surface of the air chamber 137 located outside the minimum inner diameter portion 131b, and penetrates into the minimum inner diameter portion 131b. Furthermore, an air inlet 127 is formed on the side of the main pipe 120 at a position that opens into the air chamber 137, and the insertion portion 111b of the solenoid valve assembly 110 is inserted into the air inlet 127.

[0042] Therefore, as shown by the black arrows in the figure, when liquid is introduced into the gas-liquid mixing device 100 from the inlet 132, the negative pressure generated in the minimum inner diameter section 131b draws air from the air chamber 137 through the air passage 131d, forming a liquid mixed with air (gas-liquid mixed fluid), which then flows out from the outlet 124. The diagonal arrows shown in the figure represent the flow of the gas-liquid mixed fluid out of the outlet 124. In addition, as air from the air chamber 137 is drawn into the minimum inner diameter section 131b through the air passage 131d, the same amount of air is supplied to the air chamber 137 from the solenoid valve assembly 110. The thick dashed arrows in Figure 5 represent the flow of air supplied from the solenoid valve assembly 110 through the air chamber 137 into the minimum inner diameter section 131b.

[0043] As described above, in the gas-liquid mixing device 100 of this embodiment, the air passage 131d draws in air from the air chamber 137, so it is sufficient to replenish the air chamber 137 with air. Therefore, the solenoid valve assembly 110 can be installed in a position that communicates with the air chamber 137. In other words, unlike the conventional gas-liquid mixing device 900 described above using Figure 4, the installation position of the solenoid valve assembly 110 does not necessarily have to be directly beside the minimum inner diameter portion 131b. For this reason, by preparing multiple main pipes 120 with different positions of the air inlet 127, the position of the solenoid valve assembly 110 can be changed within the range indicated by the shaded arrow in Figure 6. As a result, it is possible to ensure distance between the solenoid valve assembly 110 and other parts and piping inside the water heater 1 without changing the mounting position of the gas-liquid mixing device 100, thereby improving workability during assembly and maintenance.

[0044] In addition, since the air chamber 137 is formed around the entire circumference of the intermediate outer surface 134b of the venturi tube 130 (see Figure 1), the solenoid valve assembly 110 can be attached by projecting the mounting portion 126 in any direction from the outer surface of the main tube 120. This allows the solenoid valve assembly 110 to be moved more freely, further improving workability during assembly and maintenance. Furthermore, since the air chamber 137 can be formed in the intermediate outer surface 134b portion of the venturi tube 130 where the outer diameter is smaller, the outer diameter of the main tube 120 does not increase despite the air chamber 137 being formed inside. As a result, it can be easily installed even in narrow spaces such as inside the water heater 1.

[0045] Furthermore, the internal passage 121a of the main pipe 120 can be formed by removing the mold from the insertion port 123 (see Figure 1) into which the Venturi pipe 130 is inserted, eliminating the need to provide an opening on the opposite side of the insertion port 123. As a result, there is no need to provide a sealing plate 923 (see Figure 4) or a flange 922 (see Figure 4) for attaching the sealing plate 923, as in the conventional gas-liquid mixing device 900, thus shortening the overall length compared to the conventional gas-liquid mixing device 900. Therefore, in the gas-liquid mixing device 100 of this embodiment, even when installed in a narrow space such as when mounted on a water heater 1, there are fewer constraints on the mounting position and mounting direction. As a result, it becomes possible to secure distance from other parts and piping inside the water heater 1, improving workability during assembly and maintenance.

[0046] Several variations exist for the gas-liquid mixing apparatus 100 of the above-described embodiment. Below, these variations will be briefly described, focusing on the differences from this embodiment.

[0047] B. First variation: In the embodiment described above, the mounting portion 126 to which the solenoid valve assembly 110 is attached was described as being formed at one location on the main pipe 120. Therefore, if the position of the solenoid valve assembly 110 is to be moved, it becomes necessary to change the main pipe 120 to one in which the mounting portion 126 is formed at a different location. However, it is also possible to form mounting portions 126 at multiple locations on the main pipe 120 and select an appropriate mounting portion 126 from among these mounting portions 126 to attach the solenoid valve assembly 110.

[0048] Figure 7 is an explanatory diagram of a first modified gas-liquid mixing device 100 in which mounting portions 126 are formed at multiple locations on the main pipe 120. In the illustrated first modified example, mounting portions 126 are formed at two locations on the main pipe 120, but mounting portions 126 may be formed at three or more locations. Also, in the illustrated first modified example, the multiple mounting portions 126 are formed facing the same direction in the circumferential direction, but mounting portions 126 may be formed facing different directions offset in the circumferential direction. In such a first modified gas-liquid mixing device 100, the solenoid valve assembly 110 is attached to an appropriate mounting portion 126 from among the multiple mounting portions 126, and the air inlet 127 is sealed by attaching a sealing plate 128 equipped with an insertion portion 128a or an O-ring 128b to the other mounting portions 126. In this way, it is possible to change the mounting position of the solenoid valve assembly 110 without having to prepare multiple types of main pipes 120, thereby ensuring workability during assembly and maintenance.

[0049] C. Second variation: Furthermore, in the above-described embodiment and the first modified example, it was explained that a pair of mounting protrusions 136 are formed on the Venturi tube 130, and a pair of mounting protrusions 125 are also formed on the main tube 120. However, multiple pairs of mounting protrusions 125 may be formed on the main tube 120.

[0050] Figure 8 is an explanatory diagram of a second modified gas-liquid mixing device 100 in which multiple pairs of mounting protrusions 125, 129 are formed on the main pipe 120. In the illustrated second modified example, in addition to the pair of mounting protrusions 125, another pair of mounting protrusions 129 are formed. Therefore, as indicated by the shaded arrows in the figure, by rotating the main pipe 120 around its central axis, it is possible to switch between attaching the mounting protrusions 125 to the mounting protrusions 136 of the Venturi pipe 130 (and the flange of the upstream piping, not shown) and attaching the mounting protrusions 129. In this way, the position of the solenoid valve assembly 110 can be moved by rotating the main pipe 120.

[0051] Furthermore, as shown in Figures 1 and 2 of the gas-liquid mixing device 100 of this embodiment, if the discharge section 122 is provided protruding laterally from the main pipe 120, rotating the main pipe 120 to move the solenoid valve assembly 110 will change the orientation of the discharge section 122 (and the outlet 124). Therefore, as shown in Figure 8, the discharge section 122 may be provided coaxially with the main pipe 120. In this way, the orientation of the discharge section 122 will not change even if the main pipe 120 is rotated. Also, in Figure 8, the mounting protrusions formed on the main pipe 120 are shown as two pairs, mounting protrusions 125 and mounting protrusions 129, but three or more pairs of mounting protrusions may be formed.

[0052] D. Third variation: In the above-described embodiment, the first modification, and the second modification, an air chamber 137 was described as being formed between the internal passage 121a and the intermediate outer surface 134b of the Venturi tube 130 by inserting the Venturi tube 130 into the internal passage 121a of the substantially cylindrical main tube 120. However, if an air chamber 137 can be formed to the side of the Venturi passage 131, it is not necessarily required to use a main tube 120 having an internal passage 121a and a Venturi tube 130 to form the air chamber 137. For example, an air chamber 137 may be formed by providing a recess on the outer surface of the Venturi tube 920 of the conventional gas-liquid mixing device 900 shown in Figure 4 and covering the recess with a cover member.

[0053] Figure 9 is an explanatory diagram of a third modified gas-liquid mixing device 100. As shown in Figure 9, the third modified gas-liquid mixing device 100 has a structure in which a solenoid valve assembly 110 is attached to the side of a venturi tube 130 via a cover member 142. The venturi tube 130 has a venturi passage 131 formed inside, and mounting protrusions 136 are provided on both sides of the inlet 132 to the venturi passage 131. The shape of the venturi passage 131 formed inside the venturi tube 130 is the same as in the embodiment described above. That is, a reduced-diameter passage section 131a is formed where the inner diameter of the passage decreases downstream from the inlet 132, a minimum inner diameter section 131b is formed where the inner diameter of the passage is smallest, and an expanded-diameter passage section 131c is formed where the inner diameter of the passage increases downstream from the minimum inner diameter section 131b. Furthermore, a cylindrical discharge section 139 is provided protruding from the side of the Venturi tube 130, and an outlet 139a is opened at the lower end of the discharge section 139.

[0054] Furthermore, a mounting portion 140, which is long in the axial direction of the venturi tube 130, is provided protruding from the outer surface of the venturi tube 130, and a flat mounting surface 140a is formed on the upper surface of the mounting portion 140. In the center of the mounting surface 140a, a recess 141 is formed in the axial direction of the venturi tube 130, and a plate-shaped cover member 142 is attached so as to cover this recess 141, with a sealing member (such as a cork packing) not shown in between. As a result, an air chamber 144, which will be described later, is formed between the recess 141 formed on the outer surface of the venturi tube 130 and the cover member 142 (see Figure 10). Furthermore, an air inlet 143 is formed in the cover member 142 at a position that communicates with the air chamber 144. The solenoid valve assembly 110 is attached by inserting the insertion portion 111b into this air inlet 143 and fastening it together with the cover member 142 to the mounting portion 140 with mounting screws 114.

[0055] Figure 10 is a cross-sectional view of the gas-liquid mixing device 100 of the third modified example described above, cut by a plane passing through the central axis of the Venturi tube 130. As shown in the figure, in the third modified example, an air chamber 144 is formed by covering a recess 141 formed on the outer surface of the Venturi tube 130 with a cover member 142, and this air chamber 144 and the minimum inner diameter portion 131b of the Venturi passage 131 are in communication via an air passage 131d. Furthermore, an air inlet 143 is formed in the cover member 142 (see Figure 9), and a solenoid valve assembly 110 is attached to the air inlet 143. Therefore, as shown by the black arrows in the figure, when liquid is introduced from the inlet 132 of the venturi passage 131, the negative pressure generated in the smallest inner diameter section 131b causes air to be drawn from the solenoid valve assembly 110 into the smallest inner diameter section 131b via the air chamber 144 and air passage 131d, resulting in the mixing of air into the liquid and the formation of a gas-liquid mixed fluid.

[0056] Furthermore, in the example shown in Figure 9, the cover member 142 is installed with the air inlet 143 facing forward (closer to the inlet 132). However, the cover member 142 can also be installed with the air inlet 143 facing backward (further from the inlet 132). In this case, the position of the solenoid valve assembly 110 can be moved, as shown in Figure 11. Of course, if cover members 142 with different air inlet 143 positions are available, it will also be possible to move the solenoid valve assembly 110 to a desired position.

[0057] E. Fourth variation: Furthermore, in the third modified example described above, a recess 141 is formed in the Venturi tube 130, and the air chamber 144 is formed by covering the recess 141 with a cover member 142. However, the air chamber 144 may also be formed by forming a recess in the cover member 142 and attaching the cover member 142 to the outer surface of the Venturi tube 130.

[0058] Figure 12 is a cross-sectional view showing the general structure of the venturi tube 130 of the gas-liquid mixing device 100 of the fourth modified example described above. As shown in Figure 12, in the fourth modified example, a recess 141 is formed on the side of the cover member 142, and an air inlet 143 is formed so as to communicate with the recess 141. By attaching such a cover member 142 to the outer surface of the venturi tube 130, an air chamber 144 is formed between the venturi tube 130 and the cover member 142, and the solenoid valve assembly 110 is inserted into the air inlet 143 of the cover member 142. Even in this way, by preparing cover members 142 with different positions of the air inlet 143, it is possible to move the solenoid valve assembly 110 to a desired position.

[0059] Although the gas-liquid mixing apparatus 100 of this embodiment and various modifications have been described above, the present invention is not limited to the above embodiment and various modifications, and can be implemented in various forms without departing from the spirit of the invention. [Explanation of Symbols]

[0060] 1...Water heater, 2...Main unit case, 3...Hot water tap, 4...Bathtub 5... Circulation fitting, 10... Combustion canister, 10a... Main combustion canister, 10b...Secondary combustion canister, 12...Main burner, 13...Main heat exchanger, 14... Combustion fan, 15... Sub-burner, 16... Sub-heat exchanger 20...Gas piping, 21...Main gas solenoid valve, 22...Gas proportional valve, 23...Main gas solenoid valve, 24...Sub-gas solenoid valve, 25...Water supply piping, 26...Flow sensor, 27...Main valve, 28...Water filter, 30...Hot water supply piping, 33...Water filling piping, 34...Water filling solenoid valve, 35... Check valve, 36... Flow meter, 51... Bath supply piping, 52... Bath return piping, 54... Circulation pump, 55... Water flow switch, 56...Water temperature sensor, 100...Gas-liquid mixing device, 110...Solenoid valve assembly, 111...Body part, 111a...Flange surface, 111b...Insertion part, 111c...O-ring 112... Solenoid valve, 113... Filter, 114... Mounting screw, 120...main body pipe, 121...main body part, 121a...internal passage, 121b...inner peripheral surface, 122...discharge part, 122a...inner passage, 123...Inlet, 124...Outlet, 125...Mounting projection 125a...Mounting hole, 126...Mounting part, 126a...Mounting surface, 127...Air inlet, 128...Sealing plate, 129...Mounting projection, 130...Venturi tube, 131...Venturi passage, 131a...Reduced diameter passage section, 131b...Minimum inner diameter section, 131c... Enlarged diameter passage section, 131d... Air passage, 132... Inlet, 133...outlet, 134a...inlet side outer surface, 134b...middle outer surface, 134c...Outer surface on the outlet side, 135...O-ring, 136...Mounting projection, 136a…Mounting hole, 137…Air chamber, 139…Discharge section, 139a...Discharge port, 140...Mounting part, 140a...Mounting surface, 141...recess, 142...cover member, 143...air inlet 144...Air chamber, 900...Gas-liquid mixing device.

Claims

1. A gas-liquid mixing device comprising a venturi passage whose inner diameter narrows downstream and then widens, and an air passage opening at the minimum inner diameter portion of the passage where the inner diameter is smallest, wherein air is mixed from the air passage into the liquid flowing in from the inlet of the venturi passage and passing through the minimum inner diameter portion, and the resulting air-mixed liquid is discharged from the outlet of the venturi passage, The Venturi passage has a minimum inner diameter portion, a reduced-diameter passage portion upstream of the minimum inner diameter portion where the inner diameter of the passage decreases toward the downstream side, and an expanded-diameter passage portion downstream of the minimum inner diameter portion where the inner diameter of the passage increases toward the downstream side, and is formed inside the Venturi member, and the length of the minimum inner diameter portion in the direction of liquid flow is shorter than that of either the reduced-diameter passage portion or the expanded-diameter passage portion. The Venturi member has an air passage opening on its outer surface in the lateral direction relative to the minimum inner diameter portion of the Venturi passage, and the portion of the Venturi passage in which the reduced diameter passage portion, the minimum inner diameter portion, and the expanded diameter passage portion are formed is inserted into an internal passage formed in the cover member, thereby forming an air chamber between the outer surface of the Venturi member and the inner circumferential surface of the internal passage. The air chamber is provided not only outside the minimum inner diameter portion but also extending outside the enlarged diameter passage portion. The cover member is provided with an air inlet for allowing air to flow into the air chamber, and an electromagnetic valve for opening and closing the air inlet is attached to the air inlet. A gas-liquid mixing apparatus characterized by the following features.

2. In the gas-liquid mixing apparatus according to claim 1, The outer surface of the Venturi member is formed such that the inlet side outer surface on the side where the inlet is formed and the outlet side outer surface on the side where the outlet is formed are cylindrical in shape, and the intermediate outer surface between the inlet side outer surface and the outlet side outer surface is formed to have a smaller diameter than the inlet side outer surface and the outlet side outer surface. The minimum inner diameter portion of the Venturi passage is formed on the inner side of the intermediate outer surface, The cover member is formed in a hollow cylindrical shape and covers the entire circumference of the intermediate outer surface of the Venturi member. The inlet side outer surface and the outlet side outer surface come into contact with the inner surface of the internal passage, thereby forming the air chamber between the intermediate outer surface and the inner surface of the internal passage. A gas-liquid mixing apparatus characterized by the following features.

3. In the gas-liquid mixing apparatus according to claim 1 or claim 2, The cover member has multiple air inlets formed in it. The electromagnetic valve is attached to one of the air inlets selected from among the multiple air inlets formed therein. A gas-liquid mixing apparatus characterized by the following features.

4. A gas-liquid mixing device comprising a venturi passage whose inner diameter narrows downstream and then widens, and an air passage opening at the minimum inner diameter portion of the passage where the inner diameter is smallest, wherein air is mixed from the air passage into the liquid flowing in from the inlet of the venturi passage and passing through the minimum inner diameter portion, and the resulting air-mixed liquid is discharged from the outlet of the venturi passage, The aforementioned venturi passage is formed inside the venturi member, The air passage is opened on the outer surface of the venturi member in the direction laterally to the venturi passage, and a cover member is attached so as to cover at least the portion where the air passage is open, thereby forming an air chamber between the outer surface of the venturi member and the cover member. The cover member has multiple air inlets formed in it for allowing air to flow into the air chamber. An electromagnetic valve for opening and closing the air inlet is attached to one of the air inlets selected from among the multiple air inlets formed in various locations. A gas-liquid mixing apparatus characterized by the following features.

5. A gas-liquid mixing device comprising a venturi passage whose inner diameter narrows downstream and then widens, and an air passage opening at the minimum inner diameter portion of the passage where the inner diameter is smallest, wherein air is mixed from the air passage into the liquid flowing in from the inlet of the venturi passage and passing through the minimum inner diameter portion, and the resulting air-mixed liquid is discharged from the outlet of the venturi passage, The aforementioned venturi passage is formed inside the venturi member, The shape of the outer surface of the Venturi member in the lateral direction with respect to the Venturi passage is such that the inlet-side outer surface on the side where the inlet is formed and the outlet-side outer surface on the side where the outlet is formed are cylindrical, and the intermediate outer surface between the inlet-side outer surface and the outlet-side outer surface is formed to have a smaller diameter than the inlet-side outer surface and the outlet-side outer surface. The minimum inner diameter portion of the Venturi passage is formed on the inner side of the intermediate outer surface, and the air passage is open to the intermediate outer surface of the Venturi member. By covering the entire circumference of the intermediate outer surface of the Venturi member with a cover member formed in the shape of a hollow cylinder, an air chamber is formed between the outer surface of the Venturi member and the cover member. The cover member has multiple air inlets formed in it for introducing air into the air chamber, and one of the air inlets selected from among the multiple air inlets is fitted with an electromagnetic valve for opening and closing the air inlet. A gas-liquid mixing apparatus characterized by the following features.

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