Spray device

Abstract

To provide a spray device which can remove a liquid from a liquid passage with a suction type two fluid nozzle when spraying is stopped.SOLUTION: Start of spraying with a nozzle 10 and stopping of the spraying are controlled. Further, when the spraying is stopped, a gas supply flow rate to an atomization space 51 is increased more than that when spraying is performed to make a positive pressure in the atomization space and thereby to cause a liquid in a liquid passage 21 to reversely flow from the downstream side to the upstream side of the liquid passage.SELECTED DRAWING: Figure 3A

Description

[Technical field]

[0001] The present invention relates to a two-fluid nozzle type spray device that atomizes a liquid by using a gas. [Background technology]

[0002] Nozzles that atomize liquids are widely used for cooling spaces or materials, humidification, spraying chemicals such as sterilization or aroma, spatial design, combustion, dust control, etc. These atomization nozzles can be broadly classified into single-fluid nozzles that atomize liquid by spraying it from finer holes, and two-fluid nozzles that atomize liquid using a gas such as air, nitrogen, or steam. Between these single-fluid and two-fluid nozzles, two-fluid nozzles generally have the characteristic of having better atomization performance than single-fluid nozzles because they atomize liquid using the energy of gas.

[0003] These two-fluid nozzles are classified by the liquid supply method: one is a liquid pressure type two-fluid nozzle, which pressurizes the liquid and sends it to the nozzle, and the other is a suction type two-fluid nozzle, which creates negative pressure by passing compressed air through the nozzle, and sucks in the liquid.

[0004] An example of the operation of these two-fluid nozzles when spraying stops is the spray device described in Patent Document 1.

[0005] The spray device described in Patent Document 1, when stopping spraying, closes the gas valve 416 after closing the liquid valve 421, thereby preventing dripping and allowing spraying to be resumed in a short time, as shown in Fig. 14. Here, 411 is a two-fluid nozzle, 412 is a gas flow path, 413 is a liquid flow path, 414 is a gas supply source, 415 is a liquid supply source, 431 is a control unit, and 432 is control wiring. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-188290 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the configuration of the conventional spray device described in Patent Document 1, when spraying is stopped, after liquid valve 421 is closed, closing gas valve 416 causes a problem that liquid remains in the liquid flow path, solutes precipitate from the remaining liquid, and the precipitated solutes clog the liquid flow path. Therefore, if it is possible to prevent liquid from remaining when spraying is stopped, clogging caused by solutes contained in the medicinal liquid such as sterilization or fragrance can be prevented, and it becomes possible to use the device for spraying medicinal liquid.

[0008] The present invention has been made to solve the above problems, and has an object to provide a spray device that is capable of removing liquid from a liquid flow path when spraying is stopped. [Means for solving the problem]

[0009] According to one aspect of the present invention, a spray device includes a liquid flow path for supplying a liquid, a gas flow path for supplying a gas, and a cylindrical atomization space connected to the liquid flow path and the gas flow path, The liquid flow path is connected to the center of the upstream end surface of the atomization space, a suction type two-fluid nozzle, wherein the gas flow path is connected circumferentially around the center of the upstream end face of the atomization space, and a central axis of a downstream flow path of the gas flow path is inclined with respect to a central axis of a downstream flow path of the liquid flow path, and a control unit which controls the start and stop of spraying from the nozzle and, when the spraying is stopped, controls the liquid in the liquid flow path to flow back from the downstream side to the upstream side of the liquid flow path by increasing the flow rate of gas supplied to the atomization space to a level higher than that during spraying, thereby creating a positive pressure in the atomization space. Effect of the Invention

[0010] As described above, according to the spray device of the above aspect of the present invention, it is possible to remove the liquid in the liquid flow path when spraying is stopped. In other words, when spraying is stopped, the gas supply flow rate for supplying the gas to the atomization space is increased from that during spraying to create a positive pressure in the atomization space, and the liquid passing through the liquid flow path is caused to flow back to the liquid supply source. Therefore, it is possible to suppress the liquid from remaining in the liquid flow path after spraying is stopped, and it is possible to suppress the liquid flow path from being blocked by solutes precipitated from the remaining liquid. [Brief description of the drawings]

[0011] [Figure 1] Schematic cutaway end view of a suction type two-fluid nozzle according to the first embodiment of the present invention. [Diagram 2] FIG. 1 is a perspective view of the appearance of a suction-type two-fluid nozzle according to a first embodiment of the present invention; [Figure 3A] FIG. 1 is a block diagram of a spray device according to a first embodiment of the present invention. [Figure 3B] FIG. 1 is an explanatory diagram of a spray state in the vicinity of the atomization space of the spray device according to the first embodiment of the present invention. [Figure 3C] FIG. 1 is an explanatory diagram of a backflow state when spraying is stopped near the atomization space of the spray device according to the first embodiment of the present invention. [Figure 4] 1 is a flowchart showing an example of opening and closing control of a gas valve accompanying start and stop of mist spraying in the first embodiment of the present invention. [Figure 5A] Schematic cutaway end view of a suction type two-fluid nozzle according to a second embodiment of the present invention. [Figure 5B] FIG. 5B is a cross-sectional view of the suction-type two-fluid nozzle according to the second embodiment of the present invention taken along line 5B-5B in FIG. [Figure 6] FIG. 13 is an external perspective view of a suction type two-fluid nozzle according to a second embodiment of the present invention. [Figure 7] FIG. 1 is a block diagram of a spray device according to a second embodiment of the present invention. [Figure 8] 11 is a flowchart showing an example of opening and closing control of a gas valve in response to start and stop of mist spraying in the second embodiment of the present invention. [Figure 9] Correlation diagram between the diameter (d2) of the atomization space 51 and the spray characteristics during backflow [Figure 10] Correlation diagram between the diameter (d2) of the atomization space 51 and the compressed air supply flow rate (Q) during backflow [Figure 11] Correlation diagram between the diameter (d1) of the liquid inlet 31a and the spray characteristics during backflow [Figure 12] Correlation diagram between the length (L) of the atomization space 51 and the spray characteristics during backflow [Figure 13] Correlation diagram between the number (n) of gas inflow passages 40 and spray characteristics during backflow [Figure 14] Diagram of the configuration of a conventional spray device described in Patent Document 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Embodiment 1) FIG. 1 is a cross-sectional view of a suction-type two-fluid nozzle in accordance with a first embodiment of the present invention.

[0013] The suction type two-fluid nozzle 10 comprises at least a liquid flow path 21 for supplying liquid, a gas flow path 22 for supplying gas, and a cylindrical atomization space 51 in which the downstream flow path of the liquid flow path 21 and the downstream flow path of the gas flow path 22 are connected to their rear ends, i.e., the upstream parts, and during spraying, liquid and gas are mixed in the atomization space 51 to form atomized droplets, which are sprayed from the downstream side of the atomization space 51, while when spraying is stopped, the liquid flows back from the atomization space 51 to the upstream side of the liquid flow path 21.

[0014] More specifically, the suction type two-fluid nozzle 10 at least comprises a suction type two-fluid nozzle main body 20 having a liquid flow path 21 and a gas flow path 22, a liquid introduction section 30 having a liquid inflow path 31 which is a flow path on the downstream side of the liquid flow path 21, a gas-liquid jetting section 50, and a gas inflow path 40 which is configured between the liquid introduction section 30 and the gas-liquid jetting section 50 and is a flow path on the downstream side of the gas flow path 22. The gas-liquid jetting section 50 has a cylindrical atomization space 51 at the tip of the central section, i.e., on the downstream side. The suction type two-fluid nozzle 10 further comprises a suction type two-fluid nozzle fixing section 70.

[0015] The suction type two-fluid nozzle main body 20 has a liquid flow path 21 arranged in the center of a cylindrical member along the direction of the central axis 11, and a roughly cylindrical gas flow path 22 arranged around the liquid flow path 21 at intervals along the direction of the central axis 11. The liquid flow path 21 and the gas flow path 22, excluding the downstream liquid inlet path 31 and the gas inlet path 40, are separated by a cylindrical portion 23 located in the center as part of the suction type two-fluid nozzle main body 20 and located on the central axis 11 of the suction type two-fluid nozzle main body 20. Only the portion near the tip, i.e., the downstream side and the downstream side, of the liquid flow path 21 is shown in the figure, and the liquid supply port (not shown) at the rear end, i.e., the upstream end, is connected to a pump connected to a liquid tank or the like via a water supply pipe, or is directly connected to a water pipe. The gas flow path 22 is also shown in the figure only in the vicinity of the tip, i.e., the downstream side and the downstream side, and the gas supply port (not shown) at the rear end, i.e., the upstream end, is connected to an air pressure source consisting of compressed air via a gas supply pipe, for example.

[0016] The downstream side of the cylindrical portion 23 protrudes slightly toward the tip side, that is, downstream side, from the suction type two-fluid nozzle main body 20 other than the cylindrical portion 23, and a liquid introduction portion 30 is fixed to the tip portion.

[0017] The liquid introduction part 30 is a roughly truncated cone-shaped member that is disposed at the tip of the suction type two-fluid nozzle body part 20 and covers the tip opening of the liquid flow path 21. A liquid inflow path 31 is formed that is disposed on the downstream side of the liquid flow path 21 and penetrates the liquid introduction part 30 in the direction along the central axis 11. A liquid inlet 31a is formed at the downstream end of the liquid inflow path 31 and communicates with the atomization space 51.

[0018] The liquid inflow path 31 is composed of a hole penetrating on the central axis 11 of the liquid introducing part 30, and the liquid flow 61 flowing through the liquid flow path 21 passes through the hole of the liquid inflow path 31 and the liquid inlet 31a and flows into the cylindrical atomization space 51.

[0019] The gas inflow path 40 is configured on the upstream side of the atomization space 51 by a gap between the outer surface of the liquid introduction part 30 and the inner surface of the gas-liquid jetting part 50, and a gas inlet 41 is formed at the downstream end of the gas inflow path 40 and is connected to the atomization space 51.

[0020] At least one gas inflow path 40 is disposed, and as an example, two are disposed at an interval of 180 degrees. The gas flow 62 flowing through these gas inflow paths 40 passes through the liquid inflow path 31 in the liquid introducing part 30, the liquid inlet 31a, and the atomization space 51, and atomizes the liquid flow 61 flowing through the liquid flow path 21 in the atomization space 51.

[0021] The gas-liquid jetting part 50 is disposed at the tip of the suction type two-fluid nozzle main body 20, and covers the suction type two-fluid nozzle main body 20 and the liquid introduction part 30, and also covers the liquid flow path 21 and the gas flow path 22, thereby forming a gas inlet 40 between the liquid introduction part 30 and the gas flow path 20. The liquid inlet 31a of the liquid inlet 31 on the tip side (i.e. downstream side) of the liquid flow path 21 is connected to the center of the end face on the rear end side (i.e. upstream side) of the atomization space 51. The gas inlet 41 of the gas inlet 40 on the tip side (i.e. downstream side) of the gas flow path 22 is connected on a circumference around the center of the end face on the rear end side (i.e. upstream side) of the atomization space 51. The central axis 42 of the gas inlet 40 of the gas flow path 22 is inclined with respect to the central axis 11 of the liquid inlet 31 of the liquid flow path 21.

[0022] Incidentally, the gas / liquid jetting part 50 and the liquid introducing part 30 have been described as separate members, but the present invention is not limited to this and they may be integrally configured as one member.

[0023] The suction type two-fluid nozzle fixing part 70 is a cylindrical member, and fixes the flange part at the upstream end of the gas / liquid jetting part 50 by clamping it between it and the downstream end face of the suction type two-fluid nozzle main body 20. It is also possible to eliminate the suction type two-fluid nozzle fixing part 70 and fix the gas / liquid jetting part 50 directly to the end face of the suction type two-fluid nozzle 10.

[0024] In this configuration, as shown in Fig. 1 and Fig. 3B, the gas supplied to the suction type two-fluid nozzle 10 flows from a gas supply port (not shown) to the nozzle tip side through the gas flow path 22 to the suction type two-fluid nozzle main body 20, becoming a gas flow 62. The gas flow 62 passes through the gas inflow path 40 and the gas inflow port 41, is supplied to the atomization space 51, and is ejected from the ejection port 52. At this time, a negative pressure is generated in the atomization space 51 due to the flow of the gas flow 62. Due to the negative pressure generated in the atomization space 51, a liquid flow 61 is supplied to the suction type two-fluid nozzle main body 20 from a liquid supply port (not shown) through the liquid flow path 21, and further through the liquid inflow path 31 and the liquid inflow port 31a in the liquid introduction part 30, to the atomization space 51. When the gas flow 62 and the liquid flow 61 are supplied to the atomization space 51, they are mixed together in the atomization space 51, and after the liquid is atomized, the mixed and atomized liquid 59 is jetted outward from the jet outlet 52 which is provided in the gas-liquid jetting part 50 and is the tip opening of the atomization space 51.

[0025] FIG. 2 shows an example of an arrangement of one liquid inlet passage 31, a plurality of, for example, six gas inlet passages 40 arranged at equal intervals, and one atomization space 51, and is a perspective external view of a portion of a suction type two-fluid nozzle 10.

[0026] FIG. 3A is a diagram showing the configuration of the spray device according to the first embodiment of the present invention. FIG. 3B is an explanatory diagram of the spray state in the vicinity of the atomization space of the spray device according to the first embodiment of the present invention. FIG. 3C is an explanatory diagram of the backflow state when spraying is stopped in the vicinity of the atomization space of the spray device according to the first embodiment of the present invention. In FIG. 3A, the spray device is composed of a suction type two-fluid nozzle 10, a spray gas flow path 101, a backflow gas flow path 102, a spray liquid flow path 103, a gas supply source 104, a liquid supply source 105, a spray pressure regulator 106, a backflow pressure regulator 107, a spray gas valve 108, a backflow gas valve 109, and a control unit 130. Note that the gas supply source 104 and / or the liquid supply source 105 may be provided separately from the spray device, if necessary.

[0027] The gas supply source 104 branches into a spray gas flow path 101 and a backflow gas flow path 102, which then merge to supply gas to the suction-type two-fluid nozzle 10.

[0028] A liquid supply source 105 supplies liquid to the suction type two-fluid nozzle 10 through a spray liquid flow path 103 .

[0029] The spray pressure regulator 106 is provided in the spray gas flow path 101, and can set the pressure of the gas supplied during spraying to be lower than the pressure of the backflow pressure regulator 107, for example, to 0.1 to 0.3 MPa.

[0030] The backflow pressure regulator 107 is provided in the backflow gas flow passage 102, and can set the pressure of the gas supplied when spraying is stopped to a pressure higher than that of the spray pressure regulator 106, for example, to 0.5 MPa.

[0031] The spray gas valve 108 is provided downstream of the spray pressure regulator 106 in the spray gas flow path 101 and is connected to the control unit 130 by spray control wiring 131. The spray gas valve 108 opens and closes when electricity is applied and de-energized from the control unit 130, and starts and stops the supply of gas from the gas supply source 104 to the suction-type two-fluid nozzle 10 via the spray gas flow path 101.

[0032] The backflow gas valve 109 is provided downstream of the backflow pressure regulator 107 in the backflow gas flow path 102 and is connected to the control unit 130 by backflow control wiring 132. It opens and closes when electricity is applied and not applied from the control unit 130, and starts and stops the supply of gas from the gas supply source 104 to the suction-type two-fluid nozzle 10 via the backflow gas flow path 102.

[0033] The gas and liquid respectively supplied to the suction type two-fluid nozzle 10 are mixed in the suction type two-fluid nozzle 10, and the liquid is atomized. The atomized liquid droplets and gas are sprayed from the suction type two-fluid nozzle 10.

[0034] The spray gas flow path 101, the backflow gas flow path 102, and the liquid flow path 103 may each be made of, for example, metal piping such as steel pipes or stainless steel pipes, or resin tubes.

[0035] As the gas supply source 104, for example, a compressor, a pump, or a blower capable of supplying compressed air at a pressure of 0.1 to 1 MPa to the spray gas flow path 101 and the backflow gas flow path 102 can be used.

[0036] As the liquid supply source 105, for example, a pump connected to a liquid tank capable of supplying liquid to the liquid flow path 103 can be used.

[0037] A regulator or a needle valve can be used as the spray pressure regulator 106 and the backflow pressure regulator 107, respectively, and the flow rate of the gas supplied to the suction type two-fluid nozzle 10 can be set. In this embodiment 1, in the spray pressure regulator 106 and the backflow pressure regulator 107, the flow rate of the gas supplied to the suction type two-fluid nozzle 10 when spraying is stopped is set to be higher than that during spraying, so that the atomization space 51 can be made positive pressure, as will be described later.

[0038] A two-way electromagnetic valve can be used as the spray gas valve 108 and the backflow gas valve 109, and it is preferable that the valve is normally closed so that the valve is closed when not energized and opens when energized.

[0039] Spraying of the suction type two-fluid nozzle 10 is started by opening the spray gas valve 108 under the control of the control unit 130 to supply gas from the gas supply source 104 through the spray gas flow path 101 to the suction type two-fluid nozzle 10, thereby supplying liquid from the liquid supply source 105 by negative pressure to the suction type two-fluid nozzle 10.

[0040] Spraying of the suction-type two-fluid nozzle 10 is stopped by controlling the control unit 130 to close the spray gas valve 108, open the backflow gas valve 109, allow the liquid to flow back from the suction-type two-fluid nozzle 10 to the liquid supply source 105, and then close the backflow gas valve 109.

[0041] The control unit 130 starts and stops spraying by controlling the opening and closing of the spraying gas valve 108 and the backflow gas valve 109 based on the information on the start and end of spraying. For example, the control unit 130 starts and stops spraying by controlling the opening and closing of the spraying gas valve 108 and the backflow gas valve 109 at a spray start time or spray stop time set in advance.

[0042] FIG. 4 is a flowchart showing a specific example of the opening and closing control of the spray gas valve 108 and the backflow gas valve 109 in association with the start and stop of mist spraying under the control of the control unit 130 in embodiment 1 of the present invention.

[0043] First, in step S1, the control unit 130 determines whether or not a preset spray start time has arrived. The control unit 130 waits until the spray start time arrives, and after the spray start time arrives, the process proceeds to step S2.

[0044] Next, in step S2, the spray gas valve 108 is opened under the control of the control unit 130. This starts spraying.

[0045] Next, in step S3, it is determined whether or not a preset spray stop time has arrived by the control unit 130. In step S3, the process waits until the spray stop time arrives, and after the spray stop time arrives, the process proceeds to step S4.

[0046] Next, in step S4, the control unit 130 controls the spray gas valve 108 to close.

[0047] Next, in step S5, the backflow gas valve 109 is opened under the control of the control unit 130. This causes backflow when spraying stops.

[0048] Next, in step S6, the backflow gas valve 109 is closed under the control of the control unit 130. This stops the backflow that occurs when spraying stops.

[0049] In this configuration, in step S2, the spray gas valve 108 is opened under the control of the control unit 130, and as a result, as shown in FIG. 3B, during spraying, the pressure set in the spray pressure regulator 106 creates a negative pressure in the atomization space 51, and atomized mist 59 can be sprayed using the suction-type two-fluid nozzle 10.

[0050] On the other hand, in step S5, the backflow gas valve 109 is opened under the control of the control unit 130, and as a result, as shown in FIG. 3C, by setting the set pressure by the backflow pressure regulator 107 to be higher than the set pressure by the spray pressure regulator 106 when spraying is stopped, the flow rate of gas supplied into the atomization space 51 of the suction type two-fluid nozzle 10 when spraying is stopped is made larger than that during spraying, creating a positive pressure in the atomization space 51, and causing the liquid flow 61 to flow back to the liquid supply source 105, i.e., from the downstream side to the upstream side of the liquid inflow path 31 and from the downstream side to the upstream side of the liquid flow path 21 like a liquid flow 65, thereby making it possible to suppress the residue of liquid in the liquid flow path 21 and the liquid inflow path 31. Here, the backflow means that, as shown in Fig. 3C, at the time of stopping spraying, the flow rate of gas such as compressed air supplied to the atomization space 51 is increased compared to that during spraying, so that at least the upstream side of the atomization space 51 is made to have a positive pressure, and a part of the gas flow 62, a gas flow 66, is made to flow from the gas inflow path 40 into the liquid inflow path 31 and the liquid flow path 21, so that the liquid flows from the downstream side to the upstream side of the liquid inflow path 31 and the liquid flow path 21 like a liquid flow 65 in the opposite direction to that during spraying. At this time, a part of the gas flow 62 contributes to the generation of the liquid flow 65 as a backflow gas flow 66, but the remaining gas flow 67 is discharged from the nozzle 52 as gas only. In addition, since the inside of the atomization space 51 is made to have a positive pressure, the liquid is not discharged from the inside of the atomization space 51 through the nozzle 52.

[0051] The reason for providing the spray pressure regulator 106 and the backflow pressure regulator 107 is to adjust the pressure on the gas inflow path 40 side when switching the pressure inside the atomization space 51 from negative to positive, and there is no need to adjust the pressure on the liquid flow path 21 side. The liquid flow path 21 side is basically at atmospheric pressure, and spraying is possible when the pressure inside the atomization space 51 (negative pressure) < the pressure on the liquid flow path 21 side (atmospheric pressure), and backflow occurs when the pressure inside the atomization space 51 (positive pressure) > the pressure on the liquid flow path 21 side (atmospheric pressure).

[0052] As described above, according to the first embodiment, when spraying is stopped, the gas supply flow rate for supplying gas to the atomization space 51 is increased compared to that during spraying, thereby creating a positive pressure in the atomization space 51 and causing the liquid passing through the liquid flow path 21 and the liquid inflow path 31 to flow back to the liquid supply source 105. Therefore, it is possible to suppress the liquid remaining in the liquid flow path 21 and the liquid inflow path 31 after spraying is stopped, and it is possible to suppress clogging of the liquid flow path 21 or the liquid inflow path 31 by solutes precipitated from the remaining liquid.

[0053] (Embodiment 2) Fig. 5A is a cross-sectional view of a suction-type two-fluid nozzle in accordance with a second embodiment of the present invention. In Fig. 5, the same components as those in Fig. 1 are designated by the same reference numerals, and the description thereof will be omitted.

[0054] The suction type two-fluid nozzle 10 is equipped with at least a spray gas flow passage 22a for supplying gas during spraying and a backflow gas flow passage 22b for supplying gas during backflow, and is connected to the upstream side of the atomization space 51.

[0055] In embodiment 1, the six gas inlet passages 40 connected to the gas flow path 22 are all used for spraying when spraying is in progress, and are all used for backflow when spraying is stopped, with pressure being switched between the spray gas valve 108, the backflow gas valve 109, the spray pressure regulator 106, and the backflow pressure regulator 107.

[0056] In contrast, in embodiment 2, the pressure regulator is omitted, and the three spray gas inlet passages 40a connected to one of the two gas flow passages 22a, 22b, the spray gas flow passage 22a, are used for spraying during spraying, while these three spray gas inlet passages 40a and the three backflow gas inlet passages 40b connected to the remaining backflow gas flow passage 22b are all used for backflow when spraying is stopped, and the cross-sectional area of ​​the passages is switched by gas valves 108 and 109.

[0057] More specifically, the suction type two-fluid nozzle 10 comprises a suction type two-fluid nozzle main body 20a having a liquid flow path 21, a spray gas flow path 22a, and a backflow gas flow path 22b, and at least a spray gas inlet path 40a which is configured between the liquid introduction section 30 and the gas-liquid jetting section 50 and is a flow path downstream of the spray gas flow path 22a, and a backflow gas inlet path 40b which is a flow path downstream of the backflow gas flow path 22b.

[0058] The suction type two-fluid nozzle main body 20a is divided into at least two cylindrical flow paths, one of which is a liquid flow path 21 arranged along the central axis 11 in the center of a cylindrical member, and the other of which is a cylindrical flow path arranged around the liquid flow path 21 at intervals along the central axis 11, forming a spray gas flow path 22a and a backflow gas flow path 22b.

[0059] The spray gas inlet passage 40a is formed on the upstream side of the atomization space 51 by a gap between the outer surface of the liquid introduction section 30 and the inner surface of the gas-liquid jetting section 50, and a spray gas inlet port 41a is formed at the downstream end of the spray gas inlet passage 40a and is connected to the atomization space 51.

[0060] At least one spray gas inflow passage 40a is disposed, and as an example, two are disposed at an interval of 180 degrees. The spray gas flow 62a flowing through these spray gas inflow passages 40a passes through the liquid inflow passage 31, the liquid inlet 31a, and the atomization space 51 in the liquid introducing part 30, and atomizes the liquid flow 61 flowing through the liquid flow path 21 in the atomization space 51.

[0061] The backflow gas inlet passage 40b is formed on the upstream side of the atomization space 51 by a gap between the outer surface of the liquid introducing section 30 and the inner surface of the gas-liquid jetting section 50, and a backflow gas inlet port 41b is formed at the downstream end of the backflow gas inlet passage 40b and is connected to the atomization space 51.

[0062] At least one counterflow gas inflow path 40b is provided, and as an example, two are provided at an interval of 180 degrees. The counterflow gas flow 62b flowing through these counterflow gas inflow paths 40b causes the liquid flow 61 flowing through the liquid inflow path 31, the liquid inlet 31a, and the atomization space 51 in the liquid introducing part 30 to flow backward to the upstream side of the liquid flow path 21, as described later.

[0063] Fig. 5B is a cross-sectional view of the suction type two-fluid nozzle in the second embodiment of the present invention taken along line 5B-5B in Fig. 5A. The liquid flow path 21 excluding the downstream liquid inflow path 31, the spray gas inflow path 40a, and the backflow gas inflow path 40b, the spray gas flow path 22a, and the backflow gas flow path 22b are separated by a cylindrical portion 23 located in the center as part of the suction type two-fluid nozzle main body 20 and located on the central axis 11 of the suction type two-fluid nozzle main body 20. The spray gas flow path 22a and the backflow gas flow path 22b are separated by a roughly trapezoidal gas flow path partition portion 24 connected to the cylindrical portion 23 as part of the suction type two-fluid nozzle main body 20.

[0064] In this configuration, as shown in Fig. 5A, the gas supplied to the suction type two-fluid nozzle 10 during spraying flows from a gas supply port (not shown) to the nozzle tip side through the spray gas flow path 22a to the suction type two-fluid nozzle main body 20a, becoming a spray gas flow 62a. The spray gas flow 62a passes through the spray gas inflow path 40a and the spray gas inflow port 41a, is supplied to the atomization space 51, and is ejected from the ejection port 52. At this time, a negative pressure is generated in the atomization space 51 due to the flow of the spray gas flow 62a. Due to the negative pressure generated in the atomization space 51, a liquid flow 61 is supplied to the suction type two-fluid nozzle main body 20a from a liquid supply port (not shown) through the liquid flow path 21, and further through the liquid inflow path 31 and the liquid inflow port 31a in the liquid introduction part 30, to the atomization space 51. When the spray gas flow 62a and the liquid flow 61 are supplied to the atomization space 51, they are mixed together within the atomization space 51, and the liquid is atomized. Then, the mixed and atomized liquid is ejected to the outside from the ejection port 52 which is provided in the gas-liquid ejection part 50 and is the tip opening of the atomization space 51.

[0065] When spraying is stopped, i.e., when backflowing, the gas supplied to the suction type two-fluid nozzle 10 flows from a gas supply port (not shown) to the nozzle tip side through the backflow gas flow passage 22b with respect to the suction type two-fluid nozzle main body 20a to become a backflow gas flow 62b, and also flows through the spray gas flow passage 22a to become a spray gas flow 62a for use in spraying. A part of the backflow gas flow 62b and the spray gas flow 62a passes through the backflow gas inflow passage 40b, the backflow gas inflow port 41b, the spray gas inflow passage 40a, and the spray gas inflow port 41a, and is supplied to the atomization space 51 and ejected from the ejection port 52. At this time, the backflow gas flow 62b and the spray gas flow 62a, which are supplied to the atomization space 51 in a larger amount than during spraying, cause a positive pressure in the atomization space 51. As a result of the positive pressure in the atomization space 51, the liquid flow 61 passing through the liquid flow path 21 flows back toward a liquid supply port (not shown) in the suction type two-fluid nozzle main body 20a.

[0066] FIG. 6 is an external perspective view of a portion of a suction-type two-fluid nozzle 10, showing an example of an arrangement of one liquid inlet 31a, a plurality of, for example, three spray gas inlet passages 40a and three backflow gas inlet passages 40b arranged at equal intervals, and one atomization space 51.

[0067] Fig. 7 is a configuration diagram of a spray device according to the second embodiment of the present invention. In Fig. 7, the same components as those in Fig. 3 are given the same reference numerals, and the description thereof will be omitted.

[0068] 7, the spray device is made up of a suction-type two-fluid nozzle 10, a spray gas flow path 101a, a backflow gas flow path 102a, a liquid flow path 103, a gas supply source 104, a liquid supply source 105, a spray gas valve 108a, a backflow gas valve 109a, and a control unit 130. Compared to Fig. 3, the spray pressure regulator 106 and the backflow pressure regulator 107 are not necessary.

[0069] The gas supply source 104 branches into a spray gas flow passage 101 a and a backflow gas flow passage 102 a , and supplies gas to the suction-type two-fluid nozzle 10 .

[0070] The spray gas valve 108a is provided in the spray gas flow path 101a and is connected to the control unit 130 by spray control wiring 131. The spray gas valve 108a opens and closes when electricity is applied or not applied from the control unit 130, and starts and stops the supply of gas from the gas supply source 104 to the suction-type two-fluid nozzle 10 via the spray gas flow path 101a.

[0071] The backflow gas valve 109a is provided in the backflow gas flow path 102a and is connected to the control unit 130 by backflow control wiring 132. It opens and closes when electricity is applied and not applied from the control unit 130, and starts and stops the supply of gas from the gas supply source 104 to the suction-type two-fluid nozzle 10 via the backflow gas flow path 102a.

[0072] The spray gas flow path 101a and the backflow gas flow path 102a may each be, for example, a metal pipe such as a steel pipe or a stainless steel pipe, or a resin tube.

[0073] A two-way electromagnetic valve can be used as the spray gas valve 108a and the backflow gas valve 109a, and it is preferable that the valve is normally closed so that the valve is closed when not energized and opens when energized.

[0074] Spraying of the suction type two-fluid nozzle 10 is started by opening the spray gas valve 108a under the control of the control unit 130 to supply gas from the gas supply source 104 through the spray gas flow path 101a to the suction type two-fluid nozzle 10, thereby supplying liquid from the liquid supply source 105 by negative pressure to the suction type two-fluid nozzle 10.

[0075] Spraying of the suction type two-fluid nozzle 10 is stopped by controlling the control unit 130 to open the backflow gas valve 109a while the spray gas valve 108a is open, and then closing the spray gas valve 108a and the backflow gas valve 109a after the liquid has flowed back from the suction type two-fluid nozzle 10 to the liquid supply source 105. Alternatively, although the six gas flow paths are illustrated with the same cross-sectional area in Fig. 5B, when the total cross-sectional area of ​​the backflow gas flow path 22b is configured to be larger than the total cross-sectional area of ​​the spray gas flow path 22a, the cross-sectional area can also be increased by opening the backflow gas valve 109a after closing the spray gas valve 108a, and closing the backflow gas valve 109a after the liquid has flowed back to the liquid supply source 105 in the same manner as in the first embodiment.

[0076] The control unit 130 starts and stops spraying by controlling the opening and closing of the spraying gas valve 108a and the backflow gas valve 109a based on the information on the start and end of spraying. For example, the control unit 130 starts and stops spraying by controlling the opening and closing of the spraying gas valve 108a and the backflow gas valve 109a at a spray start time or spray stop time set in advance.

[0077] FIG. 8 is a flowchart showing a specific example of the opening and closing control of the spray gas valve 108a and the backflow gas valve 109a in accordance with the start and stop of mist spraying under the control of the control unit 130 in the second embodiment of the present invention.

[0078] First, in step S11, it is determined whether or not a preset spray start time has arrived by the control unit 130. The process waits until the spray start time arrives, and after the spray start time arrives, the process proceeds to step S12.

[0079] Next, in step S12, the spray gas valve 108a is opened under the control of the control unit 130. This starts spraying.

[0080] Next, in step S13, it is determined whether or not a preset spray stop time has arrived by the control unit 130. In step S13, the process waits until the spray stop time arrives, and after the spray stop time arrives, the process proceeds to step S14.

[0081] Next, in step S14, the backflow gas valve 109a is opened with the spray gas valve 108a open under the control of the control unit 130. This causes backflow when spraying stops.

[0082] Next, in step S15, the spray gas valve 108a and the backflow gas valve 109a are closed under the control of the control unit 130. This stops the backflow that accompanies the cessation of spraying.

[0083] In this configuration, in step S12, the spray gas valve 108a is opened under the control of the control unit 130, and as a result, as in the previous Figure 3B, during spraying, negative pressure is created in the atomization space 51 due to the gas flow rate in the spray gas flow path 22a, and atomized mist 59 can be sprayed using the suction-type two-fluid nozzle 10.

[0084] On the other hand, in step S14, the backflow gas valve 109a is opened under the control of the control unit 130, and as a result, as shown in FIG. 3C above, when spraying is stopped, the gas flow rate in the spray gas flow path 22a and the backflow gas flow path 22b is greater than that during spraying, creating a positive pressure in the atomization space 51, and causing the liquid flow 61 to flow back to the liquid supply source 105, i.e., from the downstream side to the upstream side of the liquid inflow path 31 and from the downstream side to the upstream side of the liquid flow path 21 like a liquid flow 65, thereby preventing liquid from remaining in the liquid flow path 21 and the liquid inflow path 31.

[0085] As described above, according to the second embodiment, it is possible to achieve the same effects as those of the first embodiment.

[0086] Example 1 One of the characteristics of the suction type two-fluid nozzle 10 in the first and second embodiments is shown in Figure 9. Compressed air was used as an example of the gas, and water was used as an example of the liquid. The diameter (d1) of the liquid inlet passage 31 was 0.5 mm, the axial length (L) of the atomization space 51 was 1.5 mm, the number (n) of gas inlet passages 40 was 6, the maximum air supply pressure was 0.5 MPa, the diameters (d2) of the atomization space 51 were 0.75, 1.0, 1.25, and 1.5 mm, respectively, and the total cross-sectional areas (S) of the gas inlet ports 41 were 0.204, 0.306, 0.408, and 0.613 mm, respectively. 2 The supply pressure and supply flow rate during backflow were measured.

[0087] The diameter (d2) of the atomization space 51 is 0.75 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.204, 0.306, 0.408, and 0.613 mm. 2 In the case of (a), the pressure loss in the atomization space 51 was large, so that the water could not be sucked in and could not be sprayed.

[0088] The diameter (d2) of the atomization space 51 is 1.0 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.613 mm 2 In the case of (a), the pressure loss in the atomization space 51 was large, so that the water could not be sucked in and could not be sprayed.

[0089] The diameter (d2) of the atomization space 51 is 1.0 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.204, 0.306, or 0.408 mm. 2 In this case, water can be sucked in and sprayed.

[0090] The diameter (d2) of the atomization space 51 is 1.25 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.204, 0.306, 0.408, and 0.613 mm. 2 In this case, water can be sucked in and sprayed.

[0091] The diameter (d2) of the atomization space 51 is 1.5 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.204, 0.306, 0.408, and 0.613 mm. 2 In this case, water can be sucked in and sprayed.

[0092] The diameter (d2) of the atomization space 51 is 1.0 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.204, 0.306, or 0.408 mm. 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 12.6, 13.0, and 12.1 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 12.6, Q ≥ 13.0, and 12.1 L / min, respectively.

[0093] The diameter (d2) of the atomization space 51 is 1.25 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.306, 0.408, and 0.613 mm. 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 20.3, 21.1, and 21.2 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 20.3, Q ≥ 21.1, and Q ≥ 21.2 L / min, respectively.

[0094] The diameter (d2) of the atomization space 51 is 1.5 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.613 mm 2 In this case, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 28.6 L / min, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≧ 28.6 L / min.

[0095] From the results of Fig. 9, the correlation diagram between the diameter (d2) of the atomization space 51 and the compressed air supply flow rate (Q) during backflow is shown in Fig. 10. When the diameter (d2) of the atomization space 51 is 1.0 mm and the total cross-sectional area (S) of the gas inlet 41 is 0.204, 0.306, and 0.408 mm 2In this case, the diameter (d2) of the atomization space 51 is 1.25 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.306, 0.408, and 0.613 mm 2 In this case, the diameter (d2) of the atomization space 51 is 1.5 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.613 mm 2 In the case of Fig. 10, the compressed air supply flow rate (Q) during backflow is shown by dots in the range of compressed air supply pressure during backflow of 0.5 MPa or less. For all points shown in Fig. 10, if a linear equation is found so that the compressed air supply flow rate (Q) increases when the diameter (d2) of the atomization space 51 is 1.0, 1.25, and 1.5 mm, then the equation becomes Q = 32 × d2 - 17.8 L / min.

[0096] When the backflow condition formula Q≧32×d2-17.8L / min is defined and the diameter (d2) of the atomization space 51 is substituted with 1.0, 1.25, and 1.5mm, the backflow condition formulas are Q≧14.2, Q≧22.2, and Q≧30.2L / min, respectively. When the compressed air supply pressure during backflow is in the range of 0.5MPa or less, the ranges Q≧14.2, Q≧22.2, and Q≧30.2L / min calculated by substituting the diameter (d2) of the atomization space 51 with 1.0, 1.25, and 1.5mm are within the range of the compressed air supply flow rate (Q) during backflow measured when the diameter (d2) of the atomization space 51 is 1.0, 1.25, and 1.5mm, and water can be backflowed within the range of the backflow condition formula Q≧32×d2-17.8L / min.

[0097] From the above results, spraying is possible when the diameter (d2) of the atomization space 51 is in the range of 1.0mm≦d2≦1.5mm, and liquid can be backflowed when the compressed air supply pressure during backflow is in the range of 0.1MPa to 0.5MPa and the compressed air supply flow rate (Q) satisfies the backflow condition formula Q≧32×d2-17.8L / min. Here, the compressed air supply pressure during backflow is set to 0.1MPa or more because this is the minimum pressure required to atomize liquid using gas.

[0098] The following example is intended to verify whether the backflow condition for the compressed air supply flow rate (Q) is satisfied.

[0099] Example 2 One of the characteristics of the suction type two-fluid nozzle 10 in the first and second embodiments is shown in Fig. 11. Compressed air was used as an example of the gas, and water was used as an example of the liquid. The diameter (d2) of the atomization space 51 was 1.25 mm, the axial length (L) of the atomization space 51 was 1.5 mm, the number (n) of gas inflow paths 40 was 6, the maximum air supply pressure was 0.5 MPa, the diameters (d1) of the liquid inflow paths 31 were 0.4, 0.5, and 0.7 mm, respectively, and the total cross-sectional areas (S) of the gas inlets 41 were 0.204, 0.306, 0.408, and 0.613 mm, respectively. 2 The compressed air supply pressure and compressed air supply flow rate (Q) during backflow were measured.

[0100] The diameter (d1) of the liquid inflow passage 31 is 0.4, 0.5, and 0.7 mm, and the total cross-sectional area (S) of the gas inflow port 41 is 0.204, 0.306, 0.408, and 0.613 mm. 2 In this case, water can be sucked in and sprayed.

[0101] The diameter (d1) of the liquid inlet 31 is 0.4 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.306, 0.408, and 0.613 mm 2 In the case of (a), when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 20.0, 19.8, and 20.5 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 20.0, Q ≥ 19.8, and Q ≥ 20.5 L / min, respectively.

[0102] The diameter (d1) of the liquid inlet 31 is 0.5 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.306, 0.408, and 0.613 mm 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 20.3, 21.1, and 21.2 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 20.3, Q ≥ 21.1, and Q ≥ 21.2 L / min, respectively.

[0103] The diameter (d1) of the liquid inlet 31 is 0.7 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.408 and 0.613 mm. 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 22.2 and 21.4 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 22.2 and Q ≥ 21.4 L / min, respectively.

[0104] When calculating by substituting the diameter (d2) of the atomization space 51 of 1.25 mm, the backflow condition formula is Q≧22.2 L / min. When the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the range Q≧22.2 L / min of the backflow condition formula calculated by substituting the diameter (d2) of the atomization space 51 of 1.25 mm falls within the range of the compressed air supply flow rate (Q) during backflow measured when the diameter (d1) of the liquid inflow path 31 is 0.4, 0.5, and 0.7 mm, and water can be backflowed within the range of the backflow condition formula Q≧32×d2-17.8 L / min.

[0105] From the above results, it was found that spraying was possible when the diameter (d1) of the liquid inlet passage 31 was in the range of 0.4 mm≦d1≦0.7 mm, and when the compressed air supply pressure during backflow was in the range of 0.5 MPa or less, the liquid could be backflowed while the measured compressed air supply flow rate (Q) satisfied the range Q≧32×d2-17.8 L / min.

[0106] Example 3 One of the characteristics of the suction type two-fluid nozzle 10 in the first and second embodiments is shown in Figure 12. Compressed air was used as an example of the gas, and water was used as an example of the liquid. The diameter (d1) of the liquid inlet passage 31 was 0.5 mm, the diameter (d2) of the atomization space 51 was 1.25 mm, the number (n) of gas inlet passages 40 was 6, the maximum air supply pressure was 0.5 MPa, the axial length (L) of the atomization space 51 was 1.5, 3.0, and 5.0 mm, respectively, and the total cross-sectional area (S) of the gas inlet port 41 was 0.204, 0.306, 0.408, and 0.613 mm, respectively. 2 The supply pressure and supply flow rate during backflow were measured.

[0107] The axial length (L) of the atomization space 51 is 1.5, 3.0, and 5.0 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.204, 0.306, 0.408, and 0.613 mm. 2 In this case, water can be sucked in and sprayed.

[0108] The axial length (L) of the atomization space 51 is 1.5 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.306, 0.408, and 0.613 mm. 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 20.3, 21.1, and 21.2 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 20.3, Q ≥ 21.1, and Q ≥ 21.2 L / min, respectively.

[0109] The axial length (L) of the atomization space 51 is 3.0 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.306, 0.408, and 0.613 mm. 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 20.2, 21.4, and 20.2 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 20.2, Q ≥ 21.4, and Q ≥ 20.2 L / min, respectively.

[0110] The axial length (L) of the atomization space 51 is 5.0 mm, and the total cross-sectional area (S) of the gas inlet 41 is 0.306, 0.408, and 0.613 mm. 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 20.5, 22.0, and 20.3 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 20.5, Q ≥ 22.0, and Q ≥ 20.3 L / min, respectively.

[0111] When calculating by substituting the diameter (d2) of the atomization space 51 of 1.25 mm, the backflow condition formula is Q≧22.2 L / min. When the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the range Q≧22.2 L / min of the backflow condition formula calculated by substituting the diameter (d2) of the atomization space 51 of 1.25 mm falls within the range of the compressed air supply flow rate (Q) during backflow measured when the axial length (L) of the atomization space 51 is 1.5, 3.0, and 5.0 mm, and it is possible to backflow water within the range of the backflow condition formula Q≧32×d2-17.8 L / min.

[0112] From the above results, it was found that spraying was possible when the axial length (L) of the atomization space 51 was in the range of 1.5 mm≦L≦5.0 mm, and when the compressed air supply pressure during backflow was in the range of 0.5 MPa or less, the measured compressed air supply flow rate (Q) was in the range of Q≧32×d2-17.8 L / min, and liquid could be backflowed.

[0113] Example 4 One of the characteristics of the suction type two-fluid nozzle 10 in the first and second embodiments is shown in Fig. 13. Compressed air was used as an example of the gas, and water was used as an example of the liquid. The diameter (d1) of the liquid inflow path 31 was 0.5 mm, the axial length (L) of the atomization space 51 was 1.5 mm, the air supply pressure was a maximum of 0.5 MPa, the diameter (d2) of the atomization space 51 was 1.00 and 1.25 mm, respectively, the number (n) of the gas inflow paths 40 was 3 and 6, respectively, and the total cross-sectional area (S) of the gas inlet 41 was 0.204, 0.306, 0.408 and 0.613 mm, respectively. 2 The supply pressure and supply flow rate during backflow were measured.

[0114] The diameter (d2) of the atomization space 51 is 1.0 mm, the number (n) of the gas inflow passages 40 is 3 and 6, respectively, and the total cross-sectional area (S) of the gas inflow ports 41 is 0.613 mm 2 In the case of (a), the pressure loss in the atomization space 51 was large, so that the water could not be sucked in and could not be sprayed.

[0115] The diameter (d2) of the atomization space 51 is 1.0 mm, the number (n) of the gas inflow passages 40 is 3 and 6, and the total cross-sectional area (S) of the gas inflow ports 41 is 0.204, 0.306, and 0.408 mm, respectively. 2 In this case, water can be sucked in and sprayed.

[0116] The diameter (d2) of the atomization space 51 is 1.25 mm, the number (n) of the gas inflow passages 40 is 3 and 6, and the total cross-sectional area (S) of the gas inflow ports 41 is 0.204, 0.306, 0.408, and 0.613 mm, respectively. 2 In this case, water can be sucked in and sprayed.

[0117] The diameter (d2) of the atomization space 51 is 1.0 mm, the number (n) of the gas inflow passages 40 is 3, and the total cross-sectional area (S) of the gas inflow ports 41 is 0.204, 0.306, and 0.408 mm. 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 12.8, 11.4, and 10.8 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 12.8, Q ≥ 11.4, and Q ≥ 10.8 L / min, respectively.

[0118] The diameter (d2) of the atomization space 51 is 1.0 mm, the number (n) of the gas inflow passages 40 is 6, and the total cross-sectional area (S) of the gas inflow ports 41 is 0.204, 0.306, and 0.408 mm. 2 In the case of (a), when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 12.6, 13.0, and 12.1 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 12.6, Q ≥ 13.0, and Q ≥ 12.1 L / min, respectively.

[0119] The diameter (d2) of the atomization space 51 is 1.25 mm, the number (n) of the gas inflow passages 40 is 3 and 6, and the total cross-sectional area (S) of the gas inflow ports 41 is 0.306, 0.408, and 0.613 mm 2 In this case, water can be made to flow backwards as long as the compressed air supply pressure during backflow is in the range of 0.5 MPa or less.

[0120] When calculating by substituting the diameter (d2) of the atomization space 51 of 1.0 mm, the backflow condition formula is Q≧14.2 L / min. When the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the range Q≧14.2 L / min of the backflow condition formula calculated by substituting the diameter (d2) of the atomization space 51 of 1.0 mm falls within the range of the compressed air supply flow rate (Q) during backflow measured when the number (n) of gas inflow paths 40 is 3 and 6, and it is possible to backflow water within the range of the backflow condition formula Q≧32×d2-17.8 L / min.

[0121] The diameter (d2) of the atomization space 51 is 1.25 mm, the number (n) of the gas inflow passages 40 is 3, and the total cross-sectional area (S) of the gas inflow ports 41 is 0.306, 0.408, and 0.613 mm. 2 In the case of (a), when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 21.3, 19.3, and 17.9 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 21.3, Q ≥ 19.3, and Q ≥ 17.9 L / min, respectively.

[0122] The diameter (d2) of the atomization space 51 is 1.25 mm, the number (n) of the gas inflow passages 40 is 6, and the total cross-sectional area (S) of the gas inflow ports 41 is 0.306, 0.408, and 0.613 mm. 2 In the above cases, when the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the compressed air supply flow rate (Q) during backflow is 20.2, 21.4, and 20.2 L / min, respectively, and water can be backflowed when the compressed air supply flow rate (Q) is in the range of Q ≥ 20.2, Q ≥ 21.4, and Q ≥ 20.2 L / min, respectively.

[0123] When calculating by substituting the diameter (d2) of the atomization space 51 of 1.25 mm, the backflow condition formula is Q≧22.2 L / min. When the compressed air supply pressure during backflow is in the range of 0.5 MPa or less, the range Q≧22.2 L / min of the backflow condition formula calculated by substituting the diameter (d2) of the atomization space 51 of 1.25 mm falls within the range of the compressed air supply flow rate (Q) during backflow measured when the number (n) of gas inflow channels 40 is 3 and 6, and water could be backflowed while satisfying the range of the backflow condition formula Q≧32×d2-17.8 L / min.

[0124] From the above results, the suction-type two-fluid nozzle 10 of this embodiment can suck in liquid by supplying compressed air and spray liquid with a small particle size (for example, 10 μm or less), and can also backflow the liquid when the compressed air supply flow rate (Q) is in the range of the backflow condition formula Q≧32×d−17.8 L / min.

[0125] In addition, by appropriately combining any of the various embodiments or modifications described above, it is possible to achieve the effects of each of them. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features of different embodiments or examples are also possible.

[0126] (Additional Note) The above description of the embodiments discloses the following techniques.

[0127] (Technology 1) A liquid flow path for supplying a liquid, a gas flow path for supplying a gas, and a cylindrical atomization space connected to the liquid flow path and the gas flow path, The liquid flow path is connected to the center of the upstream end surface of the atomization space, a suction type two-fluid nozzle, wherein the gas flow path is connected circumferentially around the center of the upstream end face of the atomization space, and a central axis of a downstream flow path of the gas flow path is inclined with respect to a central axis of a downstream flow path of the liquid flow path, and a control unit which controls the start and stop of spraying from the nozzle, and which controls, when the spraying is stopped, the flow rate of gas supplied to the atomization space to be increased compared to that during spraying, thereby making the atomization space have a positive pressure, so that the liquid in the liquid flow path is caused to flow back from the downstream side to the upstream side of the liquid flow path.

[0128] (Technology 2) The spray device described in Technology 1, wherein, when the diameter d2 of the atomization space is 1.0 mm≦d2≦1.5 mm and the relationship between the diameter d2 of the atomization space and the gas supply flow rate Q is Q≧32×d2−17.8 L / min, the control unit controls so that the liquid is caused to flow back from the downstream side to the upstream side of the liquid flow path within a gas supply pressure range for supplying the gas of 0.1 MPa or more and 0.5 MPa or less.

[0129] (Technique 3) The liquid is supplied from a liquid supply source to the upstream side of the liquid flow path, and the gas is supplied from a gas supply source to the upstream side of the gas flow path, while The spray device comprises: at least one gas inlet passage is provided that is connected on the downstream side of the gas flow path along a circumference around the center of the upstream end face of the atomization space, The spray device described in Technology 1 or 2, wherein the control unit controls the liquid to flow back to the liquid supply source by supplying the gas from the gas supply source to the gas inlet path when starting the spraying, and by supplying the gas from the gas supply source to the gas inlet path when stopping the spraying and increasing the gas supply flow rate compared to when spraying, thereby creating a positive pressure in the atomization space.

[0130] (Technique 4) The liquid is supplied from a liquid supply source to the upstream side of the liquid flow path, and the gas is supplied from a gas supply source to the upstream side of the gas flow path, while The spray device comprises: at least two of the gas inlet passages are provided, which connect the gas flow passage to a circumference around the center of the upstream end face of the atomization space, The spray device described in Technology 1 or 2, wherein the control unit controls so that, when starting the spraying, the gas is supplied from the gas supply source to one of the at least two gas inlet paths, and, when stopping the spraying, the control unit supplies the gas from the gas supply source to the at least two gas inlet paths in an amount greater than that at the start of spraying, thereby increasing the gas supply flow rate compared to that during spraying and creating a positive pressure in the atomization space, thereby causing the liquid to flow back to the liquid supply source.

[0131] (Technical 5) A gas supply source that supplies the gas to the suction-type two-fluid nozzle branches into a spray gas flow path and a backflow gas flow path, and then merges with the gas to supply the gas to the suction-type two-fluid nozzle; The spray device comprises: a spray gas valve provided in the spray gas flow path and configured to start and stop the supply of the gas from the gas supply source through the spray gas flow path to the suction-type two-fluid nozzle by opening and closing control of the control unit; a backflow gas valve that is provided in the backflow gas flow path and starts and stops the supply of the gas from the gas supply source to the suction-type two-fluid nozzle through the backflow gas flow path by opening and closing control of the control unit, The spray device according to any one of Techniques 1 to 4, wherein when the control unit controls the start and stop of spraying of the nozzle, the spray gas valve is opened to start the supply of the gas to the suction type two-fluid nozzle when starting the spraying, while the backflow gas valve is opened to start the supply of the gas to the suction type two-fluid nozzle when stopping the spraying, thereby increasing the gas supply flow rate to the atomization space compared to that during spraying, and making the atomization space a positive pressure, thereby controlling so that the liquid in the liquid flow path is caused to flow back from the downstream side to the upstream side of the liquid flow path.

[0132] With each of these configurations, it is possible to remove the liquid in the liquid flow path when spraying is stopped. In other words, when spraying is stopped, the gas supply flow rate at which the gas is supplied to the atomization space is increased from that during spraying to create a positive pressure in the atomization space, and the liquid passing through the liquid flow path is caused to flow back to the liquid supply source. Therefore, it is possible to suppress the liquid from remaining in the liquid flow path after spraying is stopped, and it is possible to suppress clogging of the liquid flow path due to solutes precipitated from the remaining liquid. [Industrial Applicability]

[0133] The spray device according to the above aspect of the present invention provides a spray device that can remove liquid from a liquid flow path when spraying is stopped, and can suppress the liquid from remaining in the liquid flow path after spraying is stopped, and can suppress clogging of the liquid flow path due to solutes precipitated from the remaining liquid. Therefore, the spray device is capable of atomizing the liquid without pressurizing it and spraying it with low-pressure compressed air, and can be widely used for spraying medicinal liquids such as sterilization or fragrance, or spatial design, etc. [Explanation of symbols]

[0134] 10 Suction type two-fluid nozzle 11 Center axis 20, 20a Suction type two-fluid nozzle body 21 Liquid flow path 22 Gas flow path 22a Spray gas flow path 22b Backflow gas flow path 23 Cylindrical section 24 Gas flow path partition 30 Liquid introduction section 31 Liquid inlet channel 31a Liquid inlet 40 Gas inlet passage 40a: Atomizing gas inlet passage 40b Backflow gas inlet passage 41 Gas inlet 41a Atomizing gas inlet 41b Backflow gas inlet 42 Central axis of gas inlet passage 50 Gas-liquid spout 51 Atomization space 52 spout 59 Mixed and atomized liquid (mist) 61 Liquid flow 62 Gas Flow 62a Atomizing gas flow 62b Gas flow for counterflow 65 Liquid reflux 66 Gas Backflow 67 Gas Flow 70 Suction type two-fluid nozzle fixing part 101 Spray gas flow path 101a: Spray gas flow path 102a Backflow gas flow path 102 Backflow gas flow path 103 Liquid flow path 104 Gas supply source 105 Liquid Source 106 Spray pressure regulator 107 Backflow pressure regulator 108, 108a Atomizing gas valve 109, 109a Backflow gas valve 130 Control section 131 Spray control wiring 132 Reverse flow control wiring 416 Gas valves 421 Liquid valves

Claims

1. The atomization device includes a liquid flow path for supplying a liquid, a gas flow path for supplying a gas, and a cylindrical atomization space connected to the liquid flow path and the gas flow path, The liquid flow path is connected to the center of the upstream end surface of the atomization space, a suction type two-fluid nozzle, wherein the gas flow path is connected circumferentially around the center of the upstream end face of the atomization space, and a central axis of a downstream flow path of the gas flow path is inclined with respect to a central axis of a downstream flow path of the liquid flow path, and a control unit which controls the start and stop of spraying from the nozzle, and which controls, when the spraying is stopped, the flow rate of gas supplied to the atomization space to be increased compared to that during spraying, thereby making the atomization space have a positive pressure, so that the liquid in the liquid flow path is caused to flow back from the downstream side to the upstream side of the liquid flow path.

2. 2. The spray device according to claim 1, wherein, when a diameter d2 of the atomization space is 1.0 mm≦d2≦1.5 mm and a relationship between the diameter d2 of the atomization space and the gas supply flow rate Q is Q≧32×d2−17.8 L / min, the control unit controls so that the liquid is caused to flow back from the downstream side to the upstream side of the liquid flow path within a gas supply pressure range for supplying the gas of 0.1 MPa or more and 0.5 MPa or less.

3. The liquid is supplied from a liquid supply source to the upstream side of the liquid flow path, and the gas is supplied from a gas supply source to the upstream side of the gas flow path, while The spray device comprises: at least one gas inlet passage connected on the downstream side of the gas flow passage on a circumference around the center of the upstream end face of the atomization space, 3. The spray device according to claim 1 or 2, wherein the control unit controls the gas to be supplied from the gas supply source to the gas inlet passage when starting the spraying, and controls the gas to be supplied from the gas supply source to the gas inlet passage when stopping the spraying, and controls the liquid to flow back to the liquid supply source by increasing the gas supply flow rate compared to that during spraying to create a positive pressure in the atomization space.

4. The liquid is supplied from a liquid supply source to the upstream side of the liquid flow path, and the gas is supplied from a gas supply source to the upstream side of the gas flow path, while The spray device comprises: at least two gas inlet passages are provided which connect the gas flow passages to a circumference around the center of the upstream end surface of the atomization space, 3. The spray device according to claim 1 or 2, wherein the control unit controls so that, when starting the spraying, the gas is supplied from the gas supply source to one of the at least two gas inlet paths, and, when stopping the spraying, the control unit controls so that the gas is supplied from the gas supply source to the at least two gas inlet paths in an amount greater than that at the start of spraying, thereby increasing the gas supply flow rate compared to that at the time of spraying and creating a positive pressure in the atomization space, thereby causing the liquid to flow back to the liquid supply source.

5. a gas supply source that supplies the gas to the suction type two-fluid nozzle branches into an atomizing gas flow path and a backflow gas flow path, the gas flow paths then merge, and then supplies the gas to the suction type two-fluid nozzle; The spray device comprises: a spray gas valve provided in the spray gas flow path and configured to start and stop the supply of the gas from the gas supply source through the spray gas flow path to the suction-type two-fluid nozzle by opening and closing control of the control unit; a backflow gas valve that is provided in the backflow gas flow path and starts and stops the supply of the gas from the gas supply source to the suction-type two-fluid nozzle through the backflow gas flow path by opening and closing control of the control unit, 3. The spray device according to claim 1 or 2, wherein, when controlling the start and stop of spraying of the nozzle by the control unit, when starting the spraying, the spray gas valve is opened to start supplying the gas to the suction type two-fluid nozzle, and when stopping the spraying, the backflow gas valve is opened to start supplying the gas to the suction type two-fluid nozzle, thereby increasing the gas supply flow rate to the atomization space compared to that during spraying, and making the atomization space a positive pressure, thereby controlling to cause the liquid in the liquid flow path to flow back from the downstream side to the upstream side of the liquid flow path.

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