Anti-dripping mechanism of double-fluid spraying device

Abstract

The invention provides an anti-dripping mechanism of a two-fluid spraying device, which does not generate dripping due to residual water, shortens the time until the spraying is stopped, reduces the influence of the installation height of a first check valve or the influence of an external environment such as an air plug, and has high robustness. And a bypass pipe that supplies air from the first air supply pipe to the second water supply pipe and discharges water in the second water supply pipe and in the two-fluid nozzle only when the primary side pressure of the second check valve is higher than the secondary side pressure of the second check valve. The first check valve has a predetermined opening pressure that is greater than the difference between the residual pressure on the primary side of the first check valve and the atmospheric pressure. When the water supply is stopped, the pressure difference between the primary side and the secondary side of the first check valve is smaller than the opening pressure, the water does not flow and the spraying is stopped, the pressure of the primary side of the second check valve becomes higher than the pressure of the secondary side, and the water in the second water supply piping and the nozzle is discharged through the air supply.

Description

Technical Field

[0001] The invention relates to a drip-proof mechanism for a dual-fluid spraying device for spraying gas and liquid in a mist form. Background Art

[0002] In the past, in factories, humidification was performed by spraying fine particles with an average diameter of about 10 μm from a two-fluid mist nozzle of gas and liquid as ultrafine mist. As a result, static electricity is less likely to be generated, preventing the reduction of manufacturing quality or the deterioration of product defective rate due to the attachment of foreign matter or misoperation of equipment. For example, in the component installation process, it is possible to prevent adverse conditions caused by static electricity, such as electrostatic damage to components or poor installation of the base, and it is also possible to expect the improvement of the comfort of the working space or the reduction of the refrigeration and air-conditioning load due to the cooling effect of the heat of vaporization. In this way, the mist spraying by the two-fluid mist nozzle does not require a large boiler, etc., and can perform local humidification while reducing operating costs. Therefore, from the perspective of reducing CO2, its introduction is also welcomed.

[0003] Such a spraying device based on a two-fluid mist nozzle is Figure 5A As shown, a main water pipe 104 is connected to a water supply source 102 via a water control valve 103 that is turned on and off, and a mist nozzle 101 is connected to the downstream end of a plurality of branch water pipes 106 connected to the main water pipe 104 at the upstream end. In addition, a main air pipe 114 is connected to an air supply source 112 via an air control valve 113 that is turned on and off, and a mist nozzle 101 is connected to the downstream end of a plurality of branch air pipes 116 connected to the main air pipe 114 at the upstream end. Based on the humidity detected by the humidity sensor, the control panel controls the opening and closing of each control valve 103, 113 to control the mist spraying.

[0004] In such a spraying device, when the mist spraying is stopped for some reason, droplets may be generated from the front end of the mist nozzle 101 .

[0005] In order to prevent this situation, the following method is proposed as a pushing method: a bypass path 122 is provided that can supply air from the air main pipe 114 to the water branch pipe 106 via an on-off valve 121, and the water in the water branch pipe 106 is pushed out and blown away by air through the bypass path 122, thereby preventing dripping from the nozzle 101 (patent document 1).

[0006] However, in larger factories, in order to remove all the water in the water branch pipe 106 of about 50m, for example, it takes a long time to stop spraying, and when spraying starts, spraying starts after the water branch pipe 106 is filled with water, so the time required to start spraying becomes longer.

[0007] To solve this situation, as a residual pressure release method, such as Figure 5B As shown, there is also a known method as follows: when spraying stops, the drain valve 130 connected to the water main pipe 104 is opened to reduce the water pressure of the water main pipe 104 and release the residual pressure, reduce the water pressure of the water branch pipe 106, and keep the water pressure on the upstream side of the mist nozzle 101 lower than the atmospheric pressure, thereby preventing water from flowing to the nozzle 101 and preventing dripping. It should be noted that the check valve 125 of the water branch pipe 106 has the function of preventing the backflow of air from the nozzle 101 and maintaining negative pressure.

[0008] Prior Art Literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application No. 2022-556972 Summary of the invention

[0011] Problems to be solved by the invention

[0012] However, in such a device, there is a problem that dripping (water dripping from the front end of the nozzle) is easily affected by the liquid piping path and is affected by the air layer in the liquid piping path. In other words, if the water pressure on the upstream side of the nozzle is not controlled to be below the atmospheric pressure even if the influence of the head difference based on the vertical length of the liquid piping, the influence of the air layer in the liquid piping path (i.e., air lock), or both is taken into account, there is a problem of dripping.

[0013] Therefore, the object of the present invention is to solve the above-mentioned problem and to provide an anti-drip mechanism for a dual-fluid spray device, which is not easily affected by the liquid piping path, is not easily affected by the air layer in the liquid piping path, and will not produce drips. In other words, no drips will be produced due to residual water, the time until spraying stops is shortened, the influence of the setting height of the first check valve or the influence of external environment such as air locks is reduced, and the robustness is improved.

[0014] Solutions to Solve Problems

[0015] In order to achieve the above-mentioned object, the present invention is constructed as follows.

[0016] According to one embodiment of the present invention, there is provided an anti-drip mechanism for a dual-fluid spraying device, the dual-fluid spraying device comprising:

[0017] at least one two-fluid nozzle which is supplied with gas and liquid and sprays the gas and the liquid;

[0018] a first water supply pipe connected to a water supply source that supplies water as the liquid via a first opening and closing valve and supplies the water;

[0019] a second water supply pipe that connects the first water supply pipe to the liquid-side inlet of the two-fluid nozzle via a first check valve and supplies the water from the first water supply pipe to the liquid-side inlet of the two-fluid nozzle;

[0020] a first air supply pipe connected to an air supply source via a second opening and closing valve to supply the air, the air supply source supplying air as the gas at a pressure lower than a supply pressure of the water; and

[0021] A second air supply pipe connects the first air supply pipe to the gas side inlet of the two-fluid nozzle, and supplies the air from the first air supply pipe to the gas side inlet of the two-fluid nozzle, wherein:

[0022] The anti-drip mechanism of the two-fluid spray device is provided with a bypass pipe, and the bypass pipe connects the first air supply pipe to the secondary side of the first check valve of the second water supply pipe via the second check valve, and the air is supplied from the first air supply pipe to the second water supply pipe only when the pressure in the first air supply pipe on the primary side of the second check valve is higher than the pressure in the second water supply pipe on the secondary side of the second check valve, so that the water in the second water supply pipe and the two-fluid nozzle is discharged, and

[0023] The first check valve has a predetermined opening pressure, which is greater than the pressure of the difference between the residual pressure of water on the primary side of the first check valve and the atmospheric pressure.

[0024] When the difference between the pressure on the primary side of the first check valve, i.e., the first water supply pipe side, and the pressure on the secondary side, i.e., the second water supply pipe side, exceeds the opening pressure of the first check valve, the water flows from the first water supply pipe to the second water supply pipe via the first check valve and is sprayed in the first water supply pipe, the second water supply pipe, and the nozzle.

[0025] When the first on-off valve is closed and the supply of water from the water supply source to the first water supply pipe is stopped, the difference between the pressure on the primary side of the first check valve, i.e., the first water supply pipe side, and the pressure on the secondary side, i.e., the second water supply pipe side, is less than the opening pressure of the first check valve, and the water does not flow from the first water supply pipe to the second water supply pipe via the first check valve in the first water supply pipe, the second water supply pipe and the nozzle, thereby stopping the spraying, and, along with the cessation of the water supply, in the second check valve of the bypass pipe, the pressure on the primary side becomes higher than the pressure on the secondary side, and the air is supplied from the first air supply pipe to the second water supply pipe to discharge the water in the second water supply pipe and the nozzle.

[0026] Effects of the Invention

[0027] According to the above scheme of the present invention, a bypass piping is provided, and the bypass piping supplies the air from the first air supply piping to the second water supply piping only when the pressure in the first air supply piping on the primary side of the second check valve is higher than the pressure in the second water supply piping on the secondary side of the second check valve, thereby discharging the water in the second water supply piping and the two-fluid nozzle, and the first check valve has a specified opening pressure, and the opening pressure is greater than the pressure of the difference between the residual pressure of the water on the primary side of the first check valve and the atmospheric pressure. Therefore, when the first on-off valve is closed to stop the water supply, the pressure difference between the primary side and the secondary side of the first check valve is less than the opening pressure, and the water does not flow in the first water supply pipe, the second water supply pipe and the nozzle through the first check valve, so that the spraying stops, and, along with the cessation of the water supply, in the second check valve of the bypass pipe, the pressure on the primary side becomes higher than the pressure on the secondary side, and the air is supplied from the first air supply pipe to the second water supply pipe to discharge the water in the second water supply pipe and the nozzle. As a result, any of the following effects are achieved: dripping will not be generated due to residual water, the time until the spraying stops is shortened, the influence of the setting height of the first check valve or the influence of external environment such as air lock is reduced, and the robustness is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram showing the structure of a two-fluid spray device according to one embodiment of the present invention.

[0029] Figure 2 It is a perspective view showing the vicinity of a nozzle including an anti-drip mechanism of a two-fluid spray device.

[0030] Figure 3A This is an explanatory diagram of a structure in which a third check valve having no cracking pressure is provided in a branch pipe for water.

[0031] Figure 3B It is shown Figure 3A Graph of the water pressure in a structure versus time.

[0032] Figure 3C This is an explanatory diagram of a structure in which a bypass pipe is further provided to eject water in the nozzle when spraying is stopped.

[0033] Figure 3D This is a graph showing the relationship between water pressure and time in a configuration in which a first check valve having a predetermined opening pressure is provided in a water branch pipe as the two-fluid sprinkler device of the present embodiment.

[0034] Figure 3E This is a diagram for explaining the conditions under which liquid does not drip from each nozzle more reliably even if water remains in the main water pipe in the present embodiment (a part of the pipes is omitted).

[0035] Figure 4A It is an explanatory diagram of the spray standby operation of the two-fluid spray device according to this embodiment.

[0036] Figure 4B It is an explanatory diagram of the spraying operation of the two-fluid spraying device according to this embodiment.

[0037] Figure 4C It is an explanatory diagram of the operation of removing water from each nozzle of the two-fluid spray device according to the present embodiment.

[0038] Figure 4D It is an explanatory diagram of the humidity of the installation space of the two-fluid sprinkler device according to the present embodiment and the open / closed state of each valve.

[0039] Figure 5A This is an explanatory diagram of a conventional structure for preventing dripping by a push-out method.

[0040] Figure 5B This is an explanatory diagram of a conventional structure for preventing dripping by a residual pressure release system.

[0041] Description of reference numerals:

[0042] 1 Two-fluid nozzle

[0043] 2 Water supply source

[0044] 3. First opening and closing valve

[0045] 3A water solenoid valve unit

[0046] 4 Main water piping

[0047] 5First check valve

[0048] 6. Water branch pipe

[0049] 6a Water common branch pipe

[0050] 6b Water with separate branch pipe

[0051] 12 Air supply source

[0052] 13 Second opening and closing valve

[0053] 13A air solenoid valve unit

[0054] 14 Main air pipe

[0055] 16 Branch pipes for air

[0056] 21 Second check valve

[0057] 22 Bypass piping

[0058] 30 Drain valve

[0059] 31 Drainage piping

[0060] 32 Drain tray

[0061] 41Fixing parts

[0062] 50 Control Department

[0063] 101 Nozzle

[0064] 102 Water supply source

[0065] 103 Water Control Valve

[0066] 104 Main water piping

[0067] 105 Third check valve

[0068] 106 Water branch pipe

[0069] 112 Air supply source

[0070] 113 Air control valve

[0071] 114 Main air pipe

[0072] 116 Air branch pipe

[0073] 121 On / Off Valve

[0074] 122 bypass piping

[0075] 125 Check Valve

[0076] 130 Drain valve

[0077] H1 Water head from the main water pipe 4 on the ceiling to the water solenoid valve unit 3A

[0078] H2 Water head from the main water pipe 4 to the first check valve 5

[0079] Detection value of P1 pressure sensor

[0080] P2 Water main pipe 4 pressure

[0081] P3 is the primary side pressure of the first check valve 5 . DETAILED DESCRIPTION

[0082] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

[0083] Figure 1 2 is a schematic diagram showing the structure of the two-fluid spray device of this embodiment. Figure 2 It is an example of an integrated four-directional nozzle body in which air flows in from above and branches in four directions, and water flows in from below and branches in four directions, and is a three-dimensional view showing the vicinity of the nozzle including an anti-drip mechanism of a two-fluid spray device.

[0084] The two-fluid spray device of this embodiment includes: at least one two-fluid nozzle 1, a water main pipe 4 as an example of a first water supply pipe, a water branch pipe 6 as an example of a second water supply pipe, an air main pipe 14 as an example of a first air supply pipe, and an air branch pipe 16 as an example of a second air supply pipe.

[0085] The two-fluid nozzle 1 is, for example, suspended from a fixture 41 of a water main pipe 4 and an air main pipe 14 installed in a factory, and at least one, for example, a plurality of, nozzles are provided. Figure 1 Specifically, four nozzles are provided, and gas (such as air) and liquid (such as water) are supplied respectively, and the air and water are sprayed out in a mist form. As an example, the four nozzles 1 are arranged in a manner that the spraying openings of the nozzles 1 face four directions in a cross shape along the horizontal direction, and the heights of the spraying openings are substantially the same.

[0086] The main water pipe 4 is arranged to extend laterally along the ceiling of the factory, for example, and is connected to a water supply source 2 that supplies water as a liquid via a first opening and closing valve 3 to supply water. The water is supplied and stopped from the water supply source 2 to the main water pipe 4 by opening and closing the first opening and closing valve 3. As an example, the first opening and closing valve 3 is configured as a water solenoid valve unit 3A having a water solenoid valve.

[0087] The water branch pipe 6 is, for example, branched from the water main pipe 4 arranged along the ceiling of the factory, and is mostly arranged in the vertical direction in a manner extending downward, and the water main pipe 4 is connected to the liquid side inlet of the two-fluid nozzle 1 via the first check valve 5, and water is supplied from the water main pipe 4 to the liquid side inlet of the two-fluid nozzle 1. The water branch pipe 6 includes, for example: a common water branch pipe 6a, whose upstream end is connected to the water main pipe 4 and the first check valve 5 is arranged in the middle; and individual water branch pipes 6b, each of which has an upstream end connected to the downstream end of the common water branch pipe 6a, and each downstream end is connected to the liquid side inlet of each two-fluid nozzle 1.

[0088] The main air pipe 14 is arranged to extend laterally along the ceiling of the factory, for example, and is connected to the air supply source 12 that supplies air as gas at a pressure lower than the supply pressure of water via the second opening and closing valve 13 to supply air. The supply and stop of air from the air supply source 12 to the main air pipe 14 are performed by opening and closing the second opening and closing valve 13. As an example, the second opening and closing valve 13 is configured as an air solenoid valve unit 13A having an air solenoid valve.

[0089] The air branch pipe 16 branches off from the air main pipe 14 arranged along the ceiling of the factory, for example, and is arranged mostly in the up-down direction in a manner extending downward, connecting the air main pipe 14 and the gas side inlet of the two-fluid nozzle 1, and supplying air from the air main pipe 14 to the gas side inlet of the two-fluid nozzle 1.

[0090] The drain valve 30 is provided in the middle of the drain pipe 31 branched from the water main pipe 4 on the downstream side of the first opening and closing valve 3, and can be closed when the first opening and closing valve 3 is opened, and opened when the first opening and closing valve 3 is closed to discharge the water in the water main pipe 4 and reduce the residual pressure. However, when the first opening and closing valve 3 is closed, the drain valve 30 is temporarily opened to drain. It should be noted that if the drain valve 30 is kept open, the water in the water main pipe 4 will eventually disappear. The drainage here is to reduce the water pressure in the water main pipe 4, not to remove all the water in the water main pipe 4. On the contrary, if all the water in the water main pipe 4 is discharged, it is necessary to fill the water main pipe 4 with water at the next start, which takes time and wastes water. It should be noted that when the first opening and closing valve 3 is set as an open valve, it functions only as an opening in one direction.

[0091] The drain pan 32 is composed of a circular receiving pan, which is suspended from a fixing 41 installed on the main water pipe 4 and the main air pipe 14 and arranged below the four nozzles 1. Even if liquid drips from the spray port of the nozzle 1, it will be caught by the drain pan 32, thereby preventing the installation space from being soaked.

[0092] Furthermore, the two-fluid sprinkler device includes the bypass pipe 22 as a drip prevention mechanism, and the first check valve 5 has a predetermined opening pressure greater than the pressure difference between the residual pressure on the primary side of the first check valve 5 and the atmospheric pressure.

[0093] First, the bypass pipe 22 connects the air main pipe 14 to the downstream side, that is, the secondary side, of the first check valve 5 of the water branch pipe 6 via the second check valve 21. Through the second check valve 21, only when the pressure on the primary side of the second check valve 21, that is, the pressure in the air main pipe 14 is higher than the pressure on the secondary side of the second check valve 21, that is, the pressure on the secondary side of the first check valve 5 of the water branch pipe 6, air is supplied from the air main pipe 14 to the water branch pipe 6, and the water in the water branch pipe 6 and the nozzle 1 is discharged from the spraying port of the nozzle 1. Through the second check valve 21, when the pressure in the air main pipe 14 is lower than the pressure on the downstream side of the first check valve 5 of the water branch pipe 6, neither air nor water flows in the bypass pipe 22.

[0094] Furthermore, a predetermined opening pressure is set for the first check valve 5 at a value greater than the difference between the residual pressure on the primary side of the first check valve 5 and the atmospheric pressure.

[0095] Here, the drip prevention mechanism based on the arrangement of the bypass pipe 22 and the setting of the predetermined opening pressure for the first check valve 5 will be described in detail.

[0096] Regarding the prevention of dripping, studies were conducted as follows.

[0097] First, if Figure 3A As shown in FIG. 1 , a configuration in which a third check valve 105 having no cracking pressure is provided in the water branch pipe 106 is considered.

[0098] In such a structure, when the first on-off valve 103 is closed and the drain valve 130 is opened to drain the water main pipe 104 to remove the residual pressure in the water main pipe 104, the water supply to the nozzle 101 is stopped. However, when the water pressure remaining on the primary side of the third check valve 105 is greater than the atmospheric pressure, the water flows to the nozzle side due to the pressure and becomes drops (refer to Figure 3B ). Therefore, it is necessary to drain water until the residual pressure on the primary side of the third check valve 105 becomes below the atmospheric pressure, and it takes time to stop the spraying. In addition, even if the water on the primary side of the third check valve 105 does not flow, if the supply pressure of the gas disappears, there is a problem that a small amount of water remaining in the nozzle 101 flows out of the nozzle 101 and performs micro-spraying.

[0099] Therefore, in order to prevent micro-spraying from the nozzle 101, as Figure 3CAs shown in FIG. 1 , it is considered that a bypass pipe 122 is further provided to eject the water in the nozzle 101 when the spraying is stopped.

[0100] This structure also has the following problems: it takes time to drain water until the residual pressure on the primary side of the third check valve 105 becomes less than the atmospheric pressure, which increases the running cost, and the robustness is low due to the influence of the installation height of the third check valve 105 and air lock.

[0101] In order to solve these problems, as a dual-fluid spraying device of this embodiment, Figure 1 and Figure 3D As shown, a first check valve 5 is provided in the branch pipe 6 for water, and the first check valve 5 has a predetermined opening pressure (greater than 0 kPa, for example, 50 kPa) greater than the pressure of the difference between the residual pressure on the primary side of the first check valve 5 and the atmospheric pressure. If so configured, if the difference between the residual pressure on the primary side of the first check valve 5 and the atmospheric pressure is less than 50 kPa, the water supply to the nozzle 1 is stopped without generating dripping, so there is no need to wait until the residual pressure on the primary side of the first check valve 5 becomes less than the atmospheric pressure, and the time until the spraying stops is shortened. In addition, the influence of the installation height of the first check valve 5 vertically below the main pipe 4 for water or the influence of the external environment such as air lock is reduced, thereby improving the robustness. In other words, if the opening pressure is set to a pressure lower than the pressure of the difference between the residual pressure on the primary side of the first check valve 5 and the atmospheric pressure, the valve will open and dripping will occur, but if the opening pressure is set to a high pressure higher than the pressure of the difference between the residual pressure on the primary side of the first check valve 5 and the atmospheric pressure, the valve will not open, that is, water will not flow to the nozzle side through the first check valve 5, and dripping can be prevented. Therefore, the opening pressure is set to a pressure at least greater than the pressure of the difference between the residual pressure on the primary side of the first check valve 5 and the atmospheric pressure.

[0102] Furthermore, the vertical arrangement relationship between the water electromagnetic valve of the first on-off valve 3 and the first check valve 5 will be described. Figure 3E The conditions under which liquid does not drip from each nozzle 1 more reliably even if water remains in the main water pipe 4 will be described.

[0103] A water solenoid valve unit 3A including a water solenoid valve as the first opening and closing valve 3 includes a pressure sensor (not shown) to detect the pressure of water in the water main pipe 4 on the downstream side of the first opening and closing valve 3 .

[0104] When the drain valve 30 provided in the middle of the drain pipe 31 branched from the water main pipe 4 on the downstream side of the first on-off valve 3 is opened, the water in the water main pipe 4 can be discharged to the atmospheric pressure through the drain pipe 31. When the detection value of the pressure sensor reaches a predetermined value or a predetermined time has passed after the drain valve is opened, the drain valve 30 is closed by the control of the control unit 50 such as a control panel.

[0105] For example, the drain valve 30 is set to be closed when the detection value P1 of the pressure sensor becomes 150 kPa. At this time, when the water head H1 from the main water pipe 4 of the ceiling to the water electromagnetic valve unit 3A is 2 m, that is, 2×9.8=19.6 kPa, the pressure of the main water pipe 4, that is, the ceiling pipe pressure P2 is P2=P1-H1=150-19.6=130.4 kPa. Therefore, if the drain valve 30 is closed to cut off the flow when the detection value P1 is 20 kPa, the pressure of the main water pipe 4 of the ceiling is constant at 130.4 kPa according to Bernoulli's theorem.

[0106] In this case, if the first check valve 5 is arranged 1 m below the main water pipe 4, when the water head H2 from the main water pipe 4 to the first check valve 5 is 1 m = 9.8 kPa, the primary side pressure P3 of the first check valve 5 is P3 = P2 + H2 = 130.4 + 9.8 = 140.2 kPa. Although air is supplied to the secondary side of the first check valve 5 via the bypass pipe 22 and the air branch pipe 16 to act on the air pressure, when the air supply stops soon and becomes atmospheric pressure, (P3 - atmospheric pressure) < opening pressure 50 kPa, and the difference (P3 - atmospheric pressure ≈ 38.9 kPa) does not exceed the opening pressure 50 kPa, so the water remaining in the main water pipe 4 on the ceiling does not flow from the primary side of the first check valve 5 to the secondary side, and even if the water remains in the main water pipe 4, it does not drip from each nozzle 1. It should be noted that if gauge pressure is used, atmospheric pressure becomes a zero reference and the pressure is a relative value to atmospheric pressure. However, for ease of understanding, the pressure here is described as an absolute value.

[0107] In this case, when draining water, if the detection value P1 of the pressure sensor reaches the atmospheric pressure, the water will not flow because the pressure will be negative even if the opening pressure is not set. However, the time required for draining water will be greatly increased.

[0108] Therefore, the opening pressure of the first check valve 5 is set, and the time when the detection value P1 of the pressure sensor becomes 150kPa or the time when it becomes 150kPa is used to shorten the time of the spraying stop action. As a result, according to the above research, the opening pressure of the first check valve 5 is set to a pressure greater than the difference between the sum of the pressure P2 of the water main pipe 4 and the water head H2 from the water main pipe 4 to the first check valve 5 and the atmospheric pressure.

[0109] According to such a configuration, water remains in the pipes 4 and 6 between the first on-off valve 3 and the first check valve 5, so that the start-up is accelerated when the spraying is resumed.

[0110] In the dual-fluid spraying device of this embodiment, the second check valve 21 of the bypass pipe 22 can also be arranged near the secondary side of the first check valve 5. If it is configured in this way, the distance from the secondary side of the first check valve 5 to the secondary side of the second check valve 21 through the bypass pipe 22 can be shortened, so the residual water accumulated in the path after the spraying stops can be reduced. In this way, the robustness against dripping can be improved.

[0111] In addition, as an example, the secondary side of the second check valve 21 is preferably arranged at a position lower than the spraying port of the nozzle 1 and connected by a U-shaped piping or the like. If configured in this way, the bypass piping 22 or the like can be shortened, and the water remaining in the piping 22 or the like can be further reduced. In addition, when the secondary side of the second check valve 21 is located at a position lower than the spraying port of the nozzle 1, water is difficult to flow in the piping, and it is more effective to prevent dripping, compared with when the secondary side of the second check valve 21 is located at a position higher than the spraying port of the nozzle 1.

[0112] In addition, when a plurality of nozzles 1 are arranged, for example, the first check valve 5 and the second check valve 21 may be arranged on the primary side of two adjacent nozzles 1. If so configured, space saving can be achieved, and the first check valve 5 and the second check valve 21 will not be soaked by the sprayed mist, thereby eliminating the influence on the spraying of the mist.

[0113] It should be noted that the first check valve 5 having a cracking pressure can also be used instead of the safety valve. If configured in this way, the component variation of the flow rate of the safety valve can be reduced, thereby ensuring a stable flow rate.

[0114] Next, as operations of the two-fluid spray device of this embodiment, a spray standby operation, a spray operation, and an operation of removing water from each nozzle 1 will be described.

[0115] <Spraying standby action>

[0116] like Figure 4A and Figure 4D As shown, since the first on-off valve 3 for water and the second on-off valve 13 for air are both closed, the water supply pressure and the air supply pressure to each pipe 4, 6, 14, 16 and each nozzle 1 are both zero, and neither water nor air is supplied to each nozzle 1, so spraying stops and spraying is in standby mode.

[0117] <Spraying Action>

[0118] like Figure 4B and Figure 4DAs shown, both the first on-off valve 3 and the second on-off valve 13 are opened to achieve a specified humidity through spraying. Thus, a water supply pressure (i.e., water pressure) of, for example, 0.449 MPa (absolute pressure) (=gauge pressure 0.348 MPa + atmospheric pressure 0.101 MPa) and an air supply pressure (i.e., air pressure) of 0.353 MPa (absolute pressure) (=gauge pressure 0.252 MPa + atmospheric pressure 0.101 MPa) are supplied to each of the pipes 4, 6, 14, 16 and each nozzle 1. Specifically, air at an air pressure of 0.353 MPa is supplied from the air supply source 12 to each nozzle 1 via the main air pipe 14 and the branch air pipes 16. Water at a water pressure of 0.449 MPa is supplied from the water supply source 2 to each nozzle 1 via the main water pipe 4 and the branch water pipes 6. In each nozzle 1, air and water are supplied for fog spraying.

[0119] Here, the air pressure of 0.353 MPa in the main air pipe 14 acts on point C at the upstream end of the bypass pipe 22, and the water pressure of 0.449 MPa in the main water pipe 4 acts on point D at the downstream end. The pressure of around 0.353 MPa at point C < the pressure of around 0.449 MPa at point D, so water does not flow from point D to point C through the second check valve 21.

[0120] If air or water is in a flowing state in the pipe, the pressure drops due to pressure loss. However, if it is assumed that the main pipes for air and water use pipes with a sufficiently large diameter, the influence of pressure loss becomes smaller. Therefore, it can be considered that the pressure at almost any position in the pipe is approximately the supply pressure. However, the diameters of the branch pipes for air and water that branch from the main pipe and lead to the nozzles are smaller than that of the main pipe, so some pressure loss occurs. Strictly speaking, the pressures before and after the second check valve 21 are not exactly the same as the values of the respective supply pressures, but are close to them, so they push against each other with pressures of the respective supply pressure levels. In addition, for the water side, the water heads H1 and H2 need to be considered. Therefore, as the difference between the water heads H1 and H2, several tens of kPa are added to the primary side of the first check valve 5 and included, and it is recognized as being at the supply pressure level.

[0121] On the other hand, before the water flows into the main water pipe 4 etc., air flows through the bypass pipe 22 to point B on the secondary side of the first check valve 5 earlier than the water, so air pressure is applied to point B. Thus, the pressure at point B is around 0.353 MPa. In contrast, when the water flows into the main water pipe 4, the pressure at point A on the primary side of the first check valve 5 is around 0.449 MPa, which is the water pressure in the main water pipe 4. Therefore, the pressure difference between point A and point B exceeds the opening pressure of 50 KPa, so water flows from point A to point B through the first check valve 5, and the water is supplied to each nozzle 1 via the branch water pipes 6.

[0122] <Operation of removing water in each nozzle 1>

[0123] like Figure 4C and Figure 4D As shown, when spraying stops after reaching a predetermined humidity, the first water on-off valve 3 is closed to stop the water (at this time, for example, P1 has residual pressure in the water main pipe 4, so it does not become atmospheric pressure). Therefore, the drain valve 30 of the drain pipe 31 branched from the water main pipe 4 on the downstream side of the first on-off valve 3 is opened to discharge the water in the water main pipe 4 and reduce the residual pressure to reduce the water pressure and maintain negative pressure. When the water supply stops, only air is kept supplied to the air main pipe 14, and is continuously supplied to each nozzle 1 through the air branch pipe 16. At this time, the air supplied to the air main pipe 14 flows to the water branch pipe 6 and each nozzle 1 through the bypass pipe 22, and the water in the bypass pipe 22, the water branch pipe 6 and each nozzle 1 is blown away and removed.

[0124] Specifically, the air pressure of the main air pipe 14, about 0.353 MPa, acts on the point C of the bypass pipe 22, and the water pressure acting on the point D disappears and becomes the atmospheric pressure. Therefore, the air pressure of about 0.353 MPa at the point C is greater than the atmospheric pressure at the point D, so the air flows from the point C to the point D via the second check valve 21. As a result, all the water in the pipes 22, 6 and the nozzles 1 from the bypass pipe 22 to the nozzle 1 via the water branch pipe 6 is blown away and discharged. After all the water in each nozzle 1 is blown away, the air supply is stopped. The time control of "blowing away all the water" varies depending on the length of the pipe, etc., and is set to 10 seconds later, for example.

[0125] On the other hand, at point B, the pressure of about 0.353 MPa is applied until the air supply is stopped, and at point A, since the water supply is stopped, it is a residual pressure smaller than the sum of the atmospheric pressure and the opening pressure, and the pressure difference between the two does not exceed the opening pressure of the first check valve 5, 50 kPa, so even if water remains in the main water pipe 4, the water will not flow from point A to point B. Since the opening pressure is designed to be the primary side pressure P3 of the first check valve 5 (residual pressure when water is stopped) - atmospheric pressure < opening pressure, the discharge is carried out until the primary side pressure P3 of the first check valve 5 becomes atmospheric pressure + opening pressure.

[0126] <Spraying standby action>

[0127] like Figure 4A and Figure 4D As shown, by stopping the air supply after all the water in each nozzle 1 is blown away, the first on-off valve 3 for water and the second on-off valve 13 for air are closed, so the water supply pressure and air supply pressure to each pipe 4, 6, 14, 16 and each nozzle 1 are zero, and neither water nor air is supplied to each nozzle 1.

[0128] The height from the maximum height of the water main pipe 4 to point A is, for example, a maximum of 2 m (about 20 kPa). When the maximum height from the water main pipe 4 to the water solenoid valve unit 3A is 3 m (about 30 kPa), the opening pressure of the first check valve 5 is not exceeded, 50 kPa, so the water does not flow under the water head from the water main pipe 4.

[0129] It should be noted that when spraying is stopped (spraying standby), the primary side of the first check valve 5 in the water path is full of water and is pressed by the water head. Even if there is residual water on the secondary side of the first check valve 5, it can be regarded as atmospheric pressure.

[0130] On the other hand, during spraying, air flows from the bypass path 22 to the secondary side of the first check valve 5, and the air pressure is slightly reduced due to the influence of pressure loss relative to the air supply pressure. However, in a minor case, the air pressure on the secondary side of the first check valve 5 becomes a state that can be regarded as "air supply pressure". On the other hand, the opening pressure on the primary side of the first check valve 5 takes effect. First, there is a residual pressure in a state where water does not pass through, and a water head is applied in the vertical direction as a part of the residual pressure. When the water supply starts, the water pressure rises, and a state of applying water supply pressure + water head pressure is achieved. When the pressure on the primary side of the first check valve 5 (= water supply pressure + water head pressure)> air supply pressure (- air pressure loss (small and negligible)) + opening pressure, the first check valve 5 finally opens. When water flows out, it is also necessary to consider the pressure loss in the water pipe, so the water pressure on the primary side of the first check valve 5 becomes water supply pressure + water head pressure - pressure loss. In addition, the first check valve itself also generates pressure loss when water passes through. It should be noted that the supply pressure of water is defined as the pressure (P1) of water supplied from the solenoid valve unit 3A having the first on-off valve 3 for water to the main water pipe 4 .

[0131] According to the above embodiment, there is a bypass pipe 22, which supplies air from the air main pipe 14 to the water branch pipe 6 only when the pressure in the air main pipe 14 on the primary side of the second check valve 21 is higher than the pressure in the water branch pipe 6 on the secondary side of the second check valve 21, so that the water in the water branch pipe 6 and the nozzle 1 is discharged, and the first check valve 5 has a specified opening pressure that is greater than the difference between the residual pressure of the water on the primary side of the first check valve 5 and the atmospheric pressure. Therefore, when the first on-off valve 3 is closed to stop the water supply, the pressure difference between the primary side and the secondary side of the first check valve 5 is smaller than the opening pressure, and the water will not flow through the first check valve 5 in the water main pipe 4, the water branch pipe 6 and the nozzle 1, thereby stopping the spraying. In addition, along with the cessation of the water supply, in the second check valve 21 of the bypass pipe 22, the pressure on the primary side becomes higher than the pressure on the secondary side, and air is supplied from the air main pipe 14 to the water branch pipe 6 to discharge the water in the water branch pipe 6 and the nozzle 1. As a result, no dripping is generated due to residual water, the time until the spraying stops is shortened, the influence of the setting height of the first check valve 5 or the influence of the external environment such as air locks is reduced, and the robustness is improved.

[0132] It should be noted that, by appropriately combining any of the above-mentioned various embodiments or variations, the respective effects can be achieved. In addition, the embodiments can be combined with each other, or the embodiments can be combined with each other, or the embodiments can be combined with the embodiments, and the features in different embodiments or embodiments can also be combined with each other.

[0133] (Note)

[0134] The following technical solutions are disclosed through the description of the above embodiments.

[0135] (Technique 1) A drip prevention mechanism for a dual-fluid spray device, the dual-fluid spray device comprising:

[0136] at least one two-fluid nozzle which is supplied with gas and liquid and sprays the gas and the liquid;

[0137] a first water supply pipe connected to a water supply source that supplies water as the liquid via a first opening and closing valve and supplies the water;

[0138] a second water supply pipe that connects the first water supply pipe to the liquid-side inlet of the two-fluid nozzle via a first check valve and supplies the water from the first water supply pipe to the liquid-side inlet of the two-fluid nozzle;

[0139] a first air supply pipe connected to an air supply source via a second opening and closing valve to supply the air, the air supply source supplying air as the gas at a pressure lower than a supply pressure of the water; and

[0140] A second air supply pipe connects the first air supply pipe to the gas side inlet of the two-fluid nozzle, and supplies the air from the first air supply pipe to the gas side inlet of the two-fluid nozzle, wherein:

[0141] The anti-drip mechanism of the two-fluid spray device is provided with a bypass pipe, and the bypass pipe connects the first air supply pipe to the secondary side of the first check valve of the second water supply pipe via the second check valve, and the air is supplied from the first air supply pipe to the second water supply pipe only when the pressure in the first air supply pipe on the primary side of the second check valve is higher than the pressure in the second water supply pipe on the secondary side of the second check valve, so that the water in the second water supply pipe and the two-fluid nozzle is discharged, and

[0142] The first check valve has a predetermined opening pressure, which is greater than the pressure of the difference between the residual pressure of water on the primary side of the first check valve and the atmospheric pressure.

[0143] When the difference between the pressure on the primary side of the first check valve, i.e., the first water supply pipe side, and the pressure on the secondary side, i.e., the second water supply pipe side, exceeds the opening pressure of the first check valve, the water flows from the first water supply pipe to the second water supply pipe via the first check valve and is sprayed in the first water supply pipe, the second water supply pipe, and the nozzle.

[0144] When the first on-off valve is closed and the supply of water from the water supply source to the first water supply pipe is stopped, the difference between the pressure on the primary side of the first check valve, i.e., the first water supply pipe side, and the pressure on the secondary side, i.e., the second water supply pipe side, is less than the opening pressure of the first check valve, and the water does not flow from the first water supply pipe to the second water supply pipe via the first check valve, but flows in the first water supply pipe, the second water supply pipe and the nozzle, thereby stopping the spraying, and, along with the cessation of the water supply, in the second check valve of the bypass pipe, the pressure on the primary side becomes higher than the pressure on the secondary side, and the air is supplied from the first air supply pipe to the second water supply pipe to discharge the water in the second water supply pipe and the nozzle.

[0145] Through this structure, when the first on-off valve is closed to stop the water supply, the pressure difference between the primary side and the secondary side of the first check valve is smaller than the opening pressure, and the water does not flow in the first water supply pipe, the second water supply pipe and the nozzle through the first check valve, so that the spraying stops, and, along with the cessation of the water supply, in the second check valve of the bypass pipe, the pressure on the primary side becomes higher than the pressure on the secondary side, and the air is supplied from the first air supply pipe to the second water supply pipe to discharge the water in the second water supply pipe and the nozzle. As a result, dripping will not be generated due to residual water, the time until the spraying stops is shortened, the influence of the setting height of the first check valve or the influence of the external environment such as air lock is reduced, and the robustness is improved.

[0146] (Technique 2) The anti-drip mechanism of the dual-fluid spray device according to Technique 1, wherein:

[0147] The first water supply pipe extends in a lateral direction on the ceiling side of the installation space of the nozzle.

[0148] The second water supply pipe extends in the vertical direction of the installation space of the nozzle, and the first check valve is arranged on the second water supply pipe.

[0149] The opening pressure of the first check valve is set to a pressure greater than the difference between the sum of the pressure of the first water supply pipe and the water head from the first water supply pipe to the first check valve and atmospheric pressure (ie, P3 - atmospheric pressure).

[0150] With this structure, when the air supply stops shortly after the water supply stops and the pressure becomes atmospheric pressure, (P3-atmospheric pressure) < opening pressure, and the difference (P3-atmospheric pressure) does not exceed the opening pressure. Therefore, for example, water remaining in the first water supply piping on the ceiling side does not flow from the primary side of the first check valve to the secondary side, and liquid does not drip from each nozzle even though water remains in the first water supply piping. In addition, since water remains in the piping between the first on-off valve and the first check valve, it can also achieve an effect of faster start-up when spraying is restarted.

[0151] (Technique 3) The anti-drip mechanism of the dual-fluid spray device according to Technique 1 or 2, wherein:

[0152] The second check valve of the bypass pipe is arranged in the vicinity of the secondary side of the first check valve.

[0153] This structure can shorten the distance from the secondary side of the first check valve to the secondary side of the second check valve via the bypass pipe, thereby reducing the residual water accumulated in the path after the spraying stops. This can improve the robustness against dripping.

[0154] (Technique 4) A drip prevention mechanism for a dual-fluid spray device according to any one of Techniques 1 to 3, wherein:

[0155] The secondary side of the second check valve is arranged below the spray port of the nozzle.

[0156] If it is configured in this way, the bypass piping can be shortened, and the water remaining in the piping can be further reduced. In addition, when the secondary side of the second check valve is located below the spraying port of the nozzle, it is difficult for water to flow in the piping, and dripping can be prevented more effectively, compared with when the secondary side of the second check valve is located above the spraying port of the nozzle.

[0157] (Technique 5) A drip prevention mechanism for a dual-fluid spray device according to any one of Techniques 1 to 4, wherein:

[0158] A plurality of the nozzles are arranged, and the first check valve and the second check valve are arranged on the primary side of the nozzles.

[0159] According to this structure, space saving can be achieved, and the sprayed mist does not wet the first check valve and the second check valve, so the influence on the spraying of the mist can be eliminated.

[0160] (Technique 6) The anti-drip mechanism of the dual-fluid spray device according to Technique 2, wherein:

[0161] The first on-off valve is a water solenoid valve.

[0162] When the opening pressure of the first check valve is set to a pressure greater than the difference between the sum of the pressure in the first water supply pipe and the water head from the first water supply pipe to the first check valve and the atmospheric pressure, the pressure in the first water supply pipe is a value obtained by subtracting the water head of the water solenoid valve from the pressure acting on the water solenoid valve.

[0163] This structure can achieve the effect of technique 2.

[0164] Industrial Applicability

[0165] The anti-drip mechanism of the dual-fluid spray device of the above-mentioned scheme of the present invention will not produce drips due to residual water, the time until spraying stops is shortened, the influence of the setting height of the first check valve or the influence of external environment such as air lock is reduced, and the robustness is improved. For example, it is useful for humidification by spraying from a dual-fluid mist nozzle of air and water in a factory.

Claims

1. A drip prevention mechanism for a dual-fluid spraying device, the dual-fluid spraying device comprising: at least one two-fluid nozzle which is supplied with gas and liquid and sprays the gas and the liquid; a first water supply pipe connected to a water supply source that supplies water as the liquid via a first opening and closing valve and supplies the water; a second water supply pipe that connects the first water supply pipe to the liquid-side inlet of the two-fluid nozzle via a first check valve and supplies the water from the first water supply pipe to the liquid-side inlet of the two-fluid nozzle; a first air supply pipe connected to an air supply source via a second opening and closing valve to supply the air, the air supply source supplying air as the gas at a pressure lower than a supply pressure of the water; and A second air supply pipe connects the first air supply pipe to the gas side inlet of the two-fluid nozzle, and supplies the air from the first air supply pipe to the gas side inlet of the two-fluid nozzle, wherein: The anti-drip mechanism of the two-fluid spray device is provided with a bypass pipe, and the bypass pipe connects the first air supply pipe to the secondary side of the first check valve of the second water supply pipe via the second check valve, and the air is supplied from the first air supply pipe to the second water supply pipe only when the pressure in the first air supply pipe on the primary side of the second check valve is higher than the pressure in the second water supply pipe on the secondary side of the second check valve, so that the water in the second water supply pipe and the two-fluid nozzle is discharged, and The first check valve has a predetermined opening pressure, which is greater than the pressure of the difference between the residual pressure of water on the primary side of the first check valve and the atmospheric pressure. When the difference between the pressure on the primary side of the first check valve, i.e., the first water supply pipe side, and the pressure on the secondary side, i.e., the second water supply pipe side, exceeds the opening pressure of the first check valve, the water flows from the first water supply pipe to the second water supply pipe via the first check valve and is sprayed in the first water supply pipe, the second water supply pipe, and the nozzle. When the first on-off valve is closed and the supply of water from the water supply source to the first water supply pipe is stopped, the difference between the pressure on the primary side of the first check valve, i.e., the first water supply pipe side, and the pressure on the secondary side, i.e., the second water supply pipe side, is less than the opening pressure of the first check valve, and the water does not flow from the first water supply pipe to the second water supply pipe via the first check valve, but flows in the first water supply pipe, the second water supply pipe and the nozzle, thereby stopping the spraying, and, along with the cessation of the water supply, in the second check valve of the bypass pipe, the pressure on the primary side becomes higher than the pressure on the secondary side, and the air is supplied from the first air supply pipe to the second water supply pipe to discharge the water in the second water supply pipe and the nozzle.

2. The anti-drip mechanism of the dual-fluid spray device according to claim 1, wherein: The first water supply pipe extends in a lateral direction on the ceiling side of the installation space of the nozzle. The second water supply pipe extends in the vertical direction of the installation space of the nozzle, and the first check valve is arranged on the second water supply pipe. The opening pressure of the first check valve is set to a pressure greater than a difference between a sum of a pressure of the first water supply pipe and a water head from the first water supply pipe to the first check valve and atmospheric pressure.

3. The anti-drip mechanism of the dual-fluid spraying device according to claim 1 or 2, wherein: The second check valve of the bypass pipe is arranged in the vicinity of the secondary side of the first check valve.

4. The anti-drip mechanism of the dual-fluid spraying device according to claim 1 or 2, wherein: The secondary side of the second check valve is arranged below the spray port of the nozzle.

5. The anti-drip mechanism of the dual-fluid spraying device according to claim 1 or 2, wherein: A plurality of the nozzles are arranged, and the first check valve and the second check valve are arranged on the primary side of the nozzles.

6. The anti-drip mechanism of the dual-fluid spray device according to claim 2, wherein: The first on-off valve is a water solenoid valve. When the opening pressure of the first check valve is set to a pressure greater than the difference between the sum of the pressure in the first water supply pipe and the water head from the first water supply pipe to the first check valve and the atmospheric pressure, the pressure in the first water supply pipe is a value obtained by subtracting the water head of the water solenoid valve from the pressure acting on the water solenoid valve.

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