WO2015147292A1 - Double fluid spraying device - Google Patents

Abstract

The double fluid spraying device is provided with: double fluid nozzles (9) for spraying an atomized fluid obtained by mixing a liquid and a gas; a liquid flow passage for supplying the liquid to the double fluid nozzles (9); a valve (18), which is provided in the liquid flow passage and is for stopping the supply of the liquid to the double fluid nozzles (9); and a liquid discharge valve (20), which is for discharging the liquid in the liquid flow passage between the valve (18) and the double fluid nozzles (9).

Description

Two-fluid spraying device

The present invention relates to a two-fluid spray device that mixes and sprays gas and liquid.

In a spraying system, it is disclosed to spray while preventing dripping from a two-fluid nozzle by a nozzle having siphon characteristics for sucking water and a continuous water supply tank for the nozzle to pump liquid (Patent Document) 1).

In a humidifier using a two-fluid nozzle, it is disclosed that the liquid in the water storage chamber is held in a small amount and has a simple configuration (see Patent Document 2).

In order to prevent dripping, a spray device is disclosed that includes a wind tunnel portion from which airflow is discharged and a spray nozzle disposed within a diameter range of a wind exhaust opening that forms the wind tunnel portion (Patent Document). 3).

In a liquid supply system that enables continuous liquid discharge using a plurality of pumps, it is disclosed that the liquid discharge state in each pump is stabilized and high-precision discharge amount control is realized (see Patent Document 4). ).

However, depending on the structure of the two-fluid spray device, dripping may occur when spraying is stopped. For example, after the supply of the liquid is stopped, the compressed air remaining in the liquid flow path expands and the liquid is pushed out, so that dripping may occur.

JP 2007-144396 A JP-A-8-278047 JP 2010-63960 A JP 2007-154733 A

An object of the present invention is to provide a two-fluid spray device that can prevent dripping.

A two-fluid spray device according to an aspect of the present invention includes a two-fluid nozzle that sprays an atomized fluid obtained by mixing a liquid and a gas, a liquid flow passage that supplies the liquid to the two-fluid nozzle, A liquid supply stop means provided in the liquid flow passage for stopping the supply of the liquid to the two-fluid nozzle; and the liquid in the liquid flow passage between the liquid supply stop means and the two-fluid nozzle. Liquid discharging means for discharging.

FIG. 1 is a schematic configuration diagram of a system to which a two-fluid spray device according to an embodiment of the present invention is applied. FIG. 2 is a schematic configuration diagram showing a state during normal spraying in the two-fluid spraying device by the gas pressurization method of the present embodiment. FIG. 3 is a schematic configuration diagram illustrating a state in which stop control for preventing dripping is started in the two-fluid spray device of the present embodiment. FIG. 4 is a schematic configuration diagram showing a state in which the drain valve is opened during the pressure drop of the compressed gas in the two-fluid spray device of the present embodiment. FIG. 5 is a schematic configuration diagram showing a completed state of stop control for preventing dripping in the two-fluid spray device of the present embodiment. FIG. 6 is a diagram illustrating a control timing chart for preventing dripping in the two-fluid spraying device of the present embodiment. FIG. 7 is a configuration diagram illustrating a configuration in which the two-fluid nozzle of the present embodiment is connected to a pressurized liquid supply system pipe and a compressed gas supply system pipe. FIG. 8 is a configuration diagram showing the configuration of the gas pressurization type two-fluid nozzle of the present embodiment. FIG. 9 is a configuration diagram showing the configuration of the two-fluid nozzle having siphon characteristics according to the present embodiment.

Hereinafter, embodiments will be described with reference to the drawings.

(Embodiment)
With reference to FIG. 1, the outline | summary of the system with which the two-fluid spraying apparatus which concerns on this embodiment is applied is demonstrated. In addition, the same code | symbol is attached | subjected to the same part in drawing, the overlapping description is abbreviate | omitted suitably, and a different part is mainly described.

The main unit 100 is a unit constituting a two-fluid spray device. A semiconductor manufacturing apparatus 32 is installed in the clean room 31. Air supply and return air are performed between the clean room 31 and the air conditioner 33 so that the temperature and humidity in the clean room 31 become predetermined values.

The air conditioning control panel 39 detects the temperature and humidity in the clean room 31 with a detector. The air conditioning control panel 39 changes the command of the proportional control valve 41 of the chilled water supply system supplied to the cooling coil 34 built in the air conditioner 33 according to the difference between the detection result by the detector and the target value, The command of the proportional control valve 42 of the hot water supply system supplied to the heating coil 35 incorporated in the machine 33 is changed.

As a configuration other than this, in the air conditioner 33, the two-fluid spray header unit 36 having a plurality of two-fluid nozzles 9 and the atmosphere sprayed from the two-fluid spray header unit 36 are forcibly sent to the clean room 31. The fan 37 and the steam humidification unit 38 are provided. The steam humidification unit 38 is supplied with steam from a steam proportional control valve 43 installed outside the air conditioner 33.

A steam humidification command is given to the two-fluid spray control panel 40 from the air conditioning control panel 39. The two-fluid spray control panel 40 gives a command to the proportional control valve 43 based on the steam humidification command. A pressurized liquid supply system L and a compressed gas supply system G are connected to the two-fluid spray control panel 40. The pressurized liquid supply system L supplies, for example, pure water as a liquid. The compressed gas supply system G supplies, for example, air as a gas. Pipes are provided so that the pressurized liquid from the pressurized liquid supply system L and the compressed gas from the compressed gas supply system G are supplied to the two-fluid nozzles 9 of the two-fluid spray header unit 36, respectively.

The two-fluid nozzle 9 is a nozzle that mixes a liquid and a gas and sprays the atomized fluid (atomized fluid) on the use destination.

8 and FIG. 9, two types of two-fluid nozzles 9 a and 9 b will be described as the two-fluid nozzle 9. Although two types of two-fluid nozzles 9a and 9b will be described here, other types of two-fluid nozzles may be used as the two-fluid nozzle 9 according to this embodiment.

A description will be given of the two-fluid nozzle 9a of the reverse pressure method (gas pressurization method) shown in FIG.

The two-fluid nozzle 9a includes two gas flow ejection units 91a and a liquid flow ejection unit 92a. The liquid flow ejecting unit 92a is provided to eject a liquid flow. The liquid output from the liquid flow ejecting unit 92a is a pressurized liquid in which the liquid is pressurized. The two gas flow ejecting units 91a are inclined in the direction of the liquid flow output from the liquid flow ejecting unit 92a, and eject the gas flow, respectively. The gas output from the gas flow injection unit 91a is a compressed gas in which the gas is compressed. The gas flows respectively output from the two gas flow ejection units 91a collide with each other and collide with the liquid flow output from the liquid flow ejection unit 92a. The liquid stream collides with the two gas streams and is atomized by mixing. The two-fluid nozzle 9a is an internal mixing type nozzle in which a liquid flow and two gas flows are mixed in a mixing area provided inside. If the liquid is atomized, it may be mixed outside the two-fluid nozzle 9a. The two-fluid nozzle 9a is a counter-pressure type nozzle in which the compressed gas flows backward from the liquid flow ejection unit 92a when spraying is stopped. The gas pressurization type two-fluid nozzle 9a has high water pressure, high accuracy, and high-speed response, and can control the spray amount.

A two-fluid nozzle 9b having siphon characteristics shown in FIG. 9 will be described.

Each of the two two-fluid nozzles 9b includes two gas flow ejection units 91b and a liquid flow ejection unit 92b. The two gas flows output from the two gas flow injection units 91b and the liquid flow output from the liquid flow injection unit 92b are all output in the same direction. The liquid flow is output from the liquid flow injection unit 92b so as to be sandwiched between the two gas flows output from the two gas flow injection units 91b. The two gas flows are output at high speed adjacent to the liquid flow, so that the liquid is atomized. The liquid pumped up by the siphon principle is supplied to the liquid flow ejection unit 92b. The gas supplied to the two gas flow ejection units 91b may be compressed or not compressed. In addition, the liquid particles output from the two two-fluid nozzles 9b collide with each other, so that the atomized liquid particles become thinner. The two-fluid nozzle 9b is a nozzle in which gas does not flow backward (reverse pressure) from the liquid flow ejecting unit 92b.

The two-fluid spraying device of this embodiment includes a pressurized liquid supply system L, a compressed gas supply system G, and a drainage system D as shown in FIGS.

The pressurized liquid supply system L is in the middle of the pressurized liquid supply source 1, the pressurized liquid pipe 3 that supplies the pressurized liquid from the pressurized liquid supply source 1 to the two-fluid nozzle 9, and the pressurized liquid pipe 3. A valve 18 (PW-2V) is provided that opens and closes the passage of the pressurized liquid from the pressurized liquid supply source 1. The pressurized liquid supply source 1 is, for example, a pressurized pump. The pressurized liquid supply source 1 may be provided exclusively for the two-fluid spraying device, or another purpose liquid supply source disposed in a factory may be used. The valve 18 is, for example, an electromagnetic valve.

The compressed gas supply system G is provided in the middle of the compressed gas supply source 6, the compressed gas piping 22 that supplies the compressed gas from the compressed gas supply source 6 to the two-fluid nozzle 9, and the compressed gas piping 22. And a gas pressure controller 7 (A-EPR) disposed between the valve 23 and the two-fluid nozzle 9. The valve 23 is, for example, an electromagnetic valve. The gas pressure controller 7 can set the pressure of the compressed gas supplied to the two-fluid nozzle 9. The gas pressure controller 7 is, for example, an electropneumatic regulator.

The drainage system D branches off from the section between the valve 18 of the pressurized liquid piping 3 of the pressurized liquid supply system L and the two-fluid nozzle 9. The drainage system D discharges the liquid in the pressurized liquid pipe 19 to the outside. The drainage system D includes a drainage pipe 19 and a drainage valve 20. The drainage pipe 19 is a pipe branched from the pressurized liquid pipe 3. The drainage valve 20 is provided in the drainage pipe 19 and is located at a position lower than the injection part of the two-fluid nozzle 9. The drainage valve 20 is opened when the valve 18 is closed, so that the inside of the pressurized liquid pipe 19 is set to atmospheric pressure (or an external pressure connected to the drainage pipe 19), and the inside of the pressurized liquid pipe 19 is set. Drain the liquid. When the liquid is not discharged, the drain valve 20 is closed.

The two-fluid spray control panel 40 includes a control unit 21. The control unit 21 is configured to perform arithmetic processing with a microprocessor or the like according to a program or the like. The controller 21 stops spraying of the two-fluid nozzle 9 as follows. The controller 21 stops the supply of the pressurized liquid to the two-fluid nozzle 9 by closing the valve 18. The controller 21 reduces the pressure of the compressed gas applied to the two-fluid nozzle 9 with the valve 18 closed. The controller 21 opens the drain valve 20 before releasing the pressure of the compressed gas and releases the liquid pressure in the pressurized liquid pipe 19 to atmospheric pressure. As a result, both the siphon principle based on the height difference between the drain valve 20 and the injection part of the two-fluid nozzle 9 and the force that the compressed gas applied to the two-fluid nozzle 9 flows backward through the pressurized liquid pipe 19 work. The liquid flows into the pressurized liquid pipe 19 from the two-fluid nozzle 9 side toward the drain valve 20. In this way, the control unit 21 causes the liquid in the pressurized liquid pipe 19 to flow in the direction opposite to the original flow direction and sprays so that no dripping occurs from the tip of the two-fluid nozzle 9. Stop.

Next, stop control performed when spraying will be mainly described as control for preventing dripping in the two-fluid spray device. Note that the setting values and the like described here are examples.

FIG. 6 is a time chart for explaining the control of the control unit 21. Specifically, it is a time chart showing the relationship between the pressure output from the gas pressure controller 7 and the timing of opening and closing the three valves 18 and 20. Time t1 is when the spray command is stopped and the valve 18 is closed. Time t2 is when the spray command is given again. Time t3 is when the valve 18 is opened.

FIG. 2 shows a state during normal spraying of the two-fluid nozzle 9. The pressure of the gas output from the gas pressure controller 7 is set to 350 kPa. The pressure of the liquid output from the pressurized liquid supply source 1 is set to 330 kPa. The valve 23 and the valve 18 are in an open circuit state. The drain valve 20 is in a closed state.

FIG. 3 shows a state where the spraying operation of the two-fluid nozzle 9 is stopped. The start of stop control of the two-fluid nozzle 9 will be described with reference to FIG. The valve 23 is in an open circuit state. The drain valve 20 is in a closed state. In response to the dripping prevention control start command, the valve 18 is closed, and the supply of liquid from the pressurized liquid supply source 1 to the header liquid pipe is stopped. At the same time, the pressure in the compressed gas pipe 22 gradually becomes 0 kPa in accordance with the air pressure drop change rate restriction shown in FIG. 6 from the output pressure of the gas pressure controller 7 to 350 kPa to 0 kPa.

FIG. 4 is a diagram for explaining a state in which the drain valve 20 is opened. While the pressure of the compressed gas shown in FIG. 3 is decreasing, the drain valve 20 is opened. Specifically, when the pressure measurement value of the output of the gas pressure controller 7 reaches a preset opening permission pressure Pop (for example, 150 kPa), the drain valve 20 is opened. When the drain valve 20 is opened, a back pressure is generated in the pressurized liquid supply system L so that the compressed air flows backward, and in the nozzle header (pipe between the valve 18 and the two-fluid nozzle 9) due to the siphon principle. Of the liquid is drawn in the direction in which the liquid is discharged from the drain valve 20 to the outside.

Here, the drain valve 20 is opened after the output pressure of the gas pressure controller 7 drops to some extent, but the drain valve 20 may be opened anytime after the valve 18 is closed. Immediately after the valve 18 is closed, the output pressure of the gas pressure controller 7 has hardly decreased. For this reason, when the drain valve 20 is opened, the back pressure by the compressed air is strong, and the liquid may be discharged more than necessary. On the other hand, when the output pressure of the gas pressure controller 7 is almost lowered, the back pressure by the compressed air is weak. At this time, if there is a gas pool in the pipe, the back pressure is weakened, and the gas pool swells, so that there is a possibility that the two-fluid nozzle 9 causes liquid dripping. If the two-fluid nozzle 9 does not dripping, it is desirable to lower the output pressure of the gas pressure controller 7 and open the drain valve 20 as much as possible.

FIG. 5 shows a state where the spraying operation of the two-fluid nozzle 9 is stopped. In the state shown in FIG. 4, when the liquid in the nozzle header is discharged moderately, the drain valve 20 is closed. For example, the drain valve 20 discharges an appropriate amount of liquid by opening a preset opening time Top. By discharging the liquid in this way, spraying can be stopped without causing dripping at the two-fluid nozzle 9. Here, it is not necessary to discharge all the liquid in the nozzle header, and it is sufficient to discharge the minimum liquid that does not cause the two-fluid nozzle 9 to drip. When the liquid is a relatively valuable liquid such as pure water, it is desirable that the amount of discharged liquid is small.

FIG. 7 is a configuration diagram showing a configuration in which the two-fluid nozzle 9 is connected to the piping of the pressurized liquid supply system L and the piping of the compressed gas supply system G. This configuration is designed so that the gas is naturally discharged from the two-fluid nozzle 9 so that the gas reservoir does not stay locally in the piping of the pressurized liquid supply system L.

The connection port 103 of the gas supply pipe 101 and the connection port 104 of the liquid supply pipe 102 are connected to the input side of the main unit 100. A gas header pipe (gas main flow pipe) 11 and a liquid header pipe (liquid main flow passage) 12 are connected to the output side of the main unit 100.

The gas header pipe 11 is a compressed gas pipe 22 of a compressed gas supply system G that supplies the compressed gas from the compressed gas supply source 6 to the two-fluid nozzle 9.

The liquid header pipe 12 and the liquid buffer pipes (liquid branch passages) 13 and 13 e are pressurized liquid pipes 19 of the pressurized liquid supply system L that supply the pressurized liquid from the pressurized liquid supply source 1 to the two-fluid nozzle 9. It is. In a state where the supply of the pressurized liquid is stopped, the liquid header pipe 12 has a structure in which the pressurized liquid inside flows from the end (downstream) side to the start end (upstream) side. For example, the liquid header pipe 12 has a structure in which the straight pipe is inclined upward with respect to the direction in which the pressurized liquid is supplied.

The liquid buffer pipe 13e is connected to the end of the liquid header pipe 12 at a position higher than the end height so that the opening is positioned upward in the vertical direction. By providing the liquid buffer pipe 13 e at the terminal end of the liquid header pipe 12, no gas pool remains in the liquid header pipe 12. The plurality of liquid buffer pipes 13 are connected at positions other than the terminal end of the liquid header pipe 12 so that the openings are positioned upward in the vertical direction. The end height of the liquid buffer pipe 13 extends to a position higher than the end height of the liquid header pipe 12. The liquid buffer pipe 13 is connected to at least one two-fluid nozzle 9. The liquid buffer pipes 13 and 13e preferably have a structure having no convex portion so that no gas bubbles remain inside.

The pipe connection joint (manifold) 14 is connected to the openings of the liquid buffer pipes 13 and 13e. At both ends of each pressurized liquid pipe 15, the upper end of the pipe connection joint 14 and the liquid supply part of the two-fluid nozzle 9 are connected. The pressurized liquid pipe 15 supplies pressurized liquid to the two-fluid nozzle 9. For example, the pressurized liquid pipe 15 is a flexible vinyl pipe.

With such a configuration, when the two-fluid nozzle 9 is spraying or when spraying is temporarily stopped, it is difficult for air to accumulate inside the liquid header pipe 12, and the gas in the pipe is promptly restored when the next spraying is resumed. Is discharged from the two-fluid nozzle 9.

According to the present embodiment, the drainage valve 20 for discharging the liquid between the two-fluid nozzle 9 and the valve 18 that stops the supply of the liquid to the two-fluid nozzle 9 is provided, and when spraying is stopped, By discharging the liquid from the drain valve 20, dripping of the two-fluid nozzle 9 can be prevented.

By providing the drain valve 20 at a position lower than the spray port of the two-fluid nozzle 9, in addition to gravity, the liquid can be discharged using the principle of siphon. By utilizing the siphon principle, the liquid filling the two-fluid nozzle 9 can also be drawn into the pipe and discharged.

By opening the drain valve 20 before the output pressure of the gas pressure controller 7 is lowered, the liquid in the pipe can be discharged using the reverse pressure due to the compressed air applied to the two-fluid nozzle 9. .

By configuring the gas in the pipe to be naturally discharged from the two-fluid nozzle 9, it is possible to prevent gas from being accumulated in the pipe of the pressurized liquid supply system L. Thereby, it can prevent taking time until gas escapes at the time of the next spraying start. Further, by preventing gas accumulation in the piping of the pressurized liquid supply system L, it is possible to reliably execute dripping prevention control when spraying is stopped.

For example, if there is a gas reservoir in the piping of the pressurized liquid supply system L, the siphon principle may not work. In addition, when the reverse pressure by the compressed gas is applied to the two-fluid nozzle 9 and the dripping from the two-fluid nozzle 9 is suppressed, when the output pressure of the gas pressure controller 7 decreases, the two-fluid nozzle 9 is compressed by the reverse pressure. If the gas pool expands, there is a possibility that the liquid will leak from the two-fluid nozzle 9. Therefore, by avoiding the formation of a gas reservoir, it is possible to eliminate such a state in which dripping occurs.

By using the two-fluid nozzle 9a shown in FIG. 8 as the two-fluid nozzle 9 of the present embodiment, it is possible to suppress the dripping that is a defect, and to realize the high-performance spray control that is an advantage.

In the embodiment, a configuration in which a liquid flow path in which the liquid header pipe 12 and the liquid buffer pipes 13 and 13e are integrally formed may be formed. Alternatively, the two-fluid nozzle 9 may be directly attached to the openings of the liquid buffer pipes 13 and 13 e without providing the pipe connection joint 14 and the pressurized liquid pipe 15.

The drainage valve 20 discharges even a part of the liquid between the valve 18 that stops the supply of pressurized liquid to the two-fluid nozzle 9 and the two-fluid nozzle 9 at a position lower than the injection part of the two-fluid nozzle 9. It may be provided anywhere as long as it is possible. Specifically, if the position is lower than the two-fluid nozzle 9, any of the liquid header pipe 12, the liquid buffer pipe (liquid branch passage) 13 and 13 e, the pipe connection joint 14, and the pressurized liquid pipe 15 is selected. A drain valve 20 may be provided in the liquid flow path.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

Claims (10)

A two-fluid nozzle that sprays an atomized fluid obtained by mixing liquid and gas;
A liquid flow path for supplying the liquid to the two-fluid nozzle;
A liquid supply stop means provided in the liquid flow passage for stopping the supply of the liquid to the two-fluid nozzle;
A two-fluid spraying device comprising: a liquid discharging unit that discharges the liquid in the liquid flow path between the liquid supply stop unit and the two-fluid nozzle. 2. The two-fluid spraying device according to claim 1, wherein the liquid discharging means flows and discharges the liquid in a direction opposite to a flow direction of supplying the liquid to the two-fluid nozzle. The two-fluid spraying device according to claim 1, wherein the liquid discharge unit is located at a position lower than the two-fluid nozzle. The two-fluid spraying device according to claim 1, wherein the liquid discharging means discharges the liquid using gravity. The two-fluid spraying device according to claim 1, wherein the liquid discharging means discharges the liquid using a siphon principle. The two-fluid spray device according to claim 1, wherein the gas is a compressed gas under pressure. The two-fluid spraying device according to claim 6, further comprising a gas pressure control unit that controls a pressure applied to the compressed gas. The two-fluid spray device according to claim 6, wherein the two-fluid nozzle is pressurized in a direction in which the compressed gas flows backward through the liquid flow path. A control method for a two-fluid spraying device comprising a two-fluid nozzle for spraying an atomizing fluid obtained by mixing liquid and gas supplied from a liquid flow path,
When stopping spraying, close the valve provided in the liquid flow passage to stop the supply of the liquid to the two-fluid nozzle,
A control method for a two-fluid spraying device, comprising: discharging the liquid in the liquid flow path between the valve and the two-fluid nozzle after the valve is closed. The gas is a compressed gas under pressure,
The method for controlling a two-fluid spray device according to claim 9, wherein the liquid is discharged after the pressure of the gas is lowered.

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