Spraying System

Abstract

To securely prevent dripping from a spray nozzle.SOLUTION: A spray system comprises a pressure tank 3, a compression air supply source 5, and a spray pipe 7 on which a spray nozzle 6 is provided. The pressure tank 3 and the compression air supply source 5 are connected by using an air supply pipe 17 having a first electromagnetic valve; the pressure tank 3 and the spray pipe 7 are connected by using a liquid supply pipe 12 having a second electromagnetic valve. To a required part of the spray pipe 7 is connected a discharge pipe 15 having a third electromagnetic valve. When compression air is supplied to the pressure tank by putting the first and second electromagnetic valves into an open state and putting the third electromagnetic valve into a closed state, liquid in the pressure tank is sent to enable splaying by the spray nozzle 6. By putting the third electromagnetic valve into an open state simultaneously with putting the second electromagnetic valve into a closed state, liquid discharge at the discharge pipe 15 is made to reduce a rise of liquid pressure in the spray pipe after output of an off signal for the second electromagnetic valve.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a spray system that can prevent dripping from a spray nozzle. [Background technology]

[0002] In a spray system that sprays a liquid from a spray nozzle by pressurizing the liquid, a problem in the operation of the system has been how to prevent the liquid from dripping from the spray nozzle when spraying is completed.

[0003] It takes When a spray system was installed in a livestock barn, such as a cowshed, piggery, or chicken coop, it was effective as a heat countermeasure for the barn, but dripping of liquid from the spray nozzle onto the body of the animals was stressful, resulting in problems such as reduced growth and lower egg-laying rates for chickens. Furthermore, the wet floor of the barn could make the livestock slippery and potentially injure themselves. Furthermore, when such a spray system was installed in a greenhouse for growing vegetables, dripping of liquid could damage the leaves of leafy vegetables, reducing their market value, and could also result in some plants being overwatered, making them more susceptible to rotting or less likely to sprout, leading to poor growth.

[0004] It takes The main cause of the dripping phenomenon is thought to be the time required for the pressurization of the liquid to be completely stopped after the OFF signal to stop the pressurization of the liquid is output at the end of spraying.

[0005] Patent Document 1 discloses a spray system as a spray technology that prevents this dripping phenomenon. Paragraphs 0014 to 0036 of Patent Document 1 describe the best mode of the spray system as follows: Specifically, the spray system uses a pump to pressurize the liquid during spraying. The spray system is configured to spray mist by pressurizing the liquid to a predetermined pressure using the pump. When spraying is terminated, the pump's pressurization begins to decrease, and the residual pressure release valve opens when the pressure of the pressurized liquid decreases to a first pressure value. Opening the residual pressure release valve allows the residual pressure to be released to the outside. Furthermore, connecting a vacuum pump to the spray system allows for more reliable pressure reduction. The spray system also has an open valve that connects the piping to the atmosphere during or after the residual pressure release valve is activated, and a check valve that stops the supply of liquid to the spray nozzle when the pressure decreases to a second pressure value.

[0006] As described above, the spray system according to Patent Document 1 requires a check valve to stop the supply of liquid to the spray nozzle, requires a residual pressure release valve to be linked to the release valve, and further requires control based on the first pressure value and the second pressure value, resulting in a complex control system overall.

[0007] It is believed that such complex control is required because a pump is used to pressurize the liquid during spraying. That is, since the pump involves rotational or reciprocating motion, even if a signal to stop pressurizing the pump is output when spraying is finished, the pump motor enters an inertial rotation state or the plunger reciprocating device enters an inertial reciprocating state, so the liquid is not immediately shut off, resulting in an operating time lag of 3 to 5 seconds. Therefore, it is believed that during that time, the liquid continues to be supplied to the piping, causing the liquid pressure in the piping to rise.

[0008] Incidentally, Patent Document 2 describes a high-pressure spray system in which spray water supplied to two pressure tanks is pressurized by high-pressure air sent from a high-pressure air supply system, forced into the suction side of a spray pump, and discharged at high pressure from the spray pump into a spray system, where it is sprayed at high pressure from a mist nozzle.

[0009] The reason why the high-pressure spray system is equipped with a high-pressure air supply system that supplies high-pressure air to the pressure tank is as follows: Conventional high-pressure spray systems equipped with spray pumps require multiple pumps and multiple electric motors to drive the pumps, which increases the initial and running costs of the device and also increases the failure rate.

[0010] The high-pressure spray system using high-pressure air disclosed in Patent Document 2 is a system for solving such problems, but does not mention any measures to prevent dripping from the spray nozzle when spraying is complete. Furthermore, the high-pressure air from the high-pressure air supply system is used solely to pressurize the spray water supplied to the pressure tank in order to high-pressure spray from the mist nozzle, and there is no mention or suggestion whatsoever of using the high-pressure air for purposes other than high-pressure spraying. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent Publication No. 2009-148677 [Patent Document 2] Japanese Patent Application Publication No. 8-52392 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention was developed in consideration of the above-mentioned problems of the prior art, and aims to provide a spray system that effectively prevents dripping from the spray nozzle at the end of spraying in a spray system that sprays a liquid from a spray nozzle by pressurizing the liquid based on the pressure of compressed air from a compressed air supply source. Another aim of the present invention is to provide a spray system that can more effectively utilize the pressure of the compressed air to improve the performance of the entire system, reduce the system construction costs, and facilitate system maintenance. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention employs the following means. That is, a first aspect of the spray system according to the present invention comprises a pressure tank in which a liquid is stored, a compressed air supply source that supplies compressed air, and a spray pipe provided with a spray nozzle that sprays mist. The pressure tank and the compressed air supply source are 1 The pressure tank is connected to the spray pipe by an air supply pipe equipped with a solenoid valve, the pressure tank and the spray pipe are connected by a liquid supply pipe equipped with a second solenoid valve, and a discharge pipe equipped with a third solenoid valve is connected to a required portion of the spray pipe. By supplying compressed air into the pressure tank with the first and second solenoid valves in an open state and the third solenoid valve in a closed state, the liquid in the pressure tank can be delivered to the spray pipe by the pressure of the compressed air, and this delivery can spray a mist from the spray nozzle. By closing the second solenoid valve and simultaneously opening the third solenoid valve for a required time, the increase in liquid pressure in the spray pipe after the second solenoid valve's off signal is output can be reduced by discharging a required amount of the liquid from the discharge port of the discharge pipe.

[0014] A second aspect of the spray system according to the present invention comprises a pressure tank in which a liquid is stored, a compressed air supply source that supplies compressed air, and a spray pipe provided with a spray nozzle that sprays mist. The pressure tank and the compressed air supply source are 1a first solenoid valve is installed in the pressure tank, the pressure tank and the spray pipe are connected by a first air supply pipe having a second solenoid valve installed, a discharge pipe having a third solenoid valve installed in the spray pipe is connected to a required portion of the spray pipe, and the compressed air supply source and the spray pipe are connected by a second air supply pipe having a fourth solenoid valve installed. By supplying compressed air into the pressure tank with the first and second solenoid valves in an open state and the third solenoid valve in a closed state, the pressure of the compressed air can send the liquid in the pressure tank to the spray pipe, and this delivery can spray a mist from the spray nozzle. Furthermore, by closing the second solenoid valve and simultaneously opening the third solenoid valve for the required time, the increase in liquid pressure in the spray pipe after the off signal of the second solenoid valve is output can be reduced by discharging the required amount of liquid from the outlet of the discharge pipe, and by closing the first solenoid valve and opening the third and fourth solenoid valves, the compressed air is supplied to the spray pipe through the second air supply pipe, so that the liquid in the spray pipe can be discharged from the outlet of the discharge pipe and the inside of the spray pipe can be emptied.

[0015] A third aspect of the spray system according to the present invention is the spray system of the first or second aspect, wherein the pressure tank comprises a first pressure tank and a second pressure tank, the first and second pressure tanks are connected to the compressed air supply source by a first air supply pipe having a first solenoid valve installed therein, and the first and second pressure tanks are connected to the spray pipe by a liquid supply pipe having a second solenoid valve installed therein, and the open states of the first and second solenoid valves for the first pressure tank and the open states of the first and second solenoid valves for the second pressure tank are alternately repeated at predetermined time intervals.

[0016] A fourth aspect of the spray system according to the present invention comprises a first pressure tank and a second pressure tank in which a liquid is stored, a compressed air supply source that supplies compressed air, and a spray pipe provided with a spray nozzle that sprays mist. The first and second pressure tanks and the compressed air supply source are 1 The first and second pressure tanks are connected by a first air supply pipe with a solenoid valve interposed therein, and the spray pipes are connected to the first and second pressure tanks by liquid supply pipes with a second solenoid valve interposed therein, and a discharge pipe is connected to a required portion of the spray pipe via a third solenoid valve. The open states of the first and second solenoid valves for the first pressure tank and the open states of the first and second solenoid valves for the second pressure tank are alternately repeated at predetermined time intervals. The first and second solenoid valves are opened and the third solenoid valve is closed for a required time period to supply the compressed air to the first pressure tank. pressure By supplying the compressed air into the pressure tank or the second pressure tank, the liquid in the pressure tank can be delivered to the spray pipe by the pressure of the compressed air, and the delivery can spray mist from the spray nozzle. No. 2 By closing the solenoid valve and simultaneously opening the third solenoid valve, the increase in liquid pressure in the spray pipe after the OFF signal of the second solenoid valve is output can be reduced by discharging a required amount of the liquid from the outlet of the discharge pipe, and by opening the third and fourth solenoid valves with the first solenoid valve closed, the increase in liquid pressure in the spray pipe after the OFF signal of the second solenoid valve is output can be reduced. But, The invention is characterized in that air is supplied to the spray pipe through air supply pipe No. 2, thereby discharging the liquid in the spray pipe through the outlet of the discharge pipe, thereby emptying the inside of the spray pipe.

[0017] A fifth aspect of the spray system according to the present invention is characterized in that, in any one of the first to fourth aspects, the supply port of the ejector, which has a supply port, an exhaust port, and a suction port that are interconnected internally, is connected to the compressed air supply source via a fifth solenoid valve, and the suction port is connected to the exhaust port of the exhaust pipe, and by opening the third solenoid valve and simultaneously opening the fifth solenoid valve to spray compressed air from the supply port toward the exhaust port, a required amount of the liquid that is causing the pressure in the spray pipe to increase is sucked from the suction port and discharged from the exhaust port.

[0018] A sixth aspect of the spray system according to the present invention is the fifth aspect, characterized in that the ejector is operated before the third solenoid valve is opened, and the operation is controlled to create a vacuum state inside the discharge pipe.

[0019] A seventh aspect of the spray system according to the present invention is the spray system according to the first or second aspect, Containment The lower part of the tank is connected to the pressure tank, and the liquid Containment The liquid in the tank is supplied to the pressure tank by gravity when the first and second solenoid valves are closed.

[0020] An eighth aspect of the spray system according to the present invention is the spray system according to the third or fourth aspect, Containment The lower part of the tank is connected to the first and second pressure tanks, and the liquid Containment The liquid in the tank is supplied to the first pressure tank and / or the second pressure tank by gravity when the first and second solenoid valves are closed.

[0021] A ninth aspect of the spray system according to the present invention is the spray system Seventh aspect The liquid discharged from the outlet of the discharge pipe flows into the liquid storage tank.

[0022] A tenth aspect of the spray system according to the present invention is characterized in that, in any one of the first to ninth aspects, the liquid is a liquid mixed with lactic acid bacteria. [Effects of the Invention]

[0023] The spray system of the present invention effectively prevents dripping from the spray nozzle at the end of spraying in a spray system that sprays a liquid from a spray nozzle by pressurizing the liquid, based on the use of the pressure of compressed air from a compressed air supply source. Furthermore, by making more effective use of the pressure of the compressed air, it is possible to provide a spray system that can achieve improved performance of the entire system, reduced system construction costs, and easier system maintenance. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is an explanatory diagram illustrating a spray system according to the present invention in a case where one pressure tank is used. [Figure 2] FIG. 2 is an explanatory diagram showing the spray system in operation to spray through the spray pipe. [Figure 3] FIG. 2 is an explanatory diagram showing the spray system in operation to empty the spray pipe. [Figure 4] 1 is an explanatory diagram illustrating a state in which the spray system reduces the pressure inside the spray pipe by the operation of an ejector attached to the discharge pipe. [Figure 5] FIG. 10 is an explanatory diagram illustrating a case where the spray system uses two pressure tanks. [Figure 6] FIG. 10 is an explanatory diagram showing the spray system in operation using one pressure tank to spray through the spray pipe. [Figure 7] FIG. 10 is an explanatory diagram showing the spray system in operation to spray through the spray pipe using the other pressure tank. [Figure 8]FIG. 2 is an explanatory diagram showing the spray system in operation to empty the spray pipe. [Figure 9] FIG. 10 is an explanatory diagram showing an example in which the discharge pipe is provided at a portion other than the tip of the spray pipe. [Figure 10] FIG. 1 is an explanatory diagram illustrating an apparatus for preparing a liquid containing lactic acid bacteria. Example 1

[0025] 1 to 3, the spray system 1 according to the present invention is installed in a livestock barn, for example, a cow barn, and includes a pressure tank 3 that stores a liquid 2, a compressed air supply source 5 that supplies compressed air, and a spray pipe 7 that is provided with a spray nozzle 6 that sprays mist (fine mist in this embodiment, and therefore also referred to as fine mist hereinafter). The pressure tank 3 and the compressed air supply source 5 are 1 The pressure tank 3 and the spray pipe 7 are connected by a first air supply pipe 10 equipped with a solenoid valve 9, the pressure tank 3 and the spray pipe 7 are connected by a liquid supply pipe 12 equipped with a second solenoid valve 11, a discharge pipe 15 equipped with a third solenoid valve 13 is connected to a required portion of the spray pipe 7, and the compressed air supply source 5 and the spray pipe 7 are connected by a second air supply pipe 17 equipped with a fourth solenoid valve 16. By supplying the compressed air into the pressure tank 3 with the first and second solenoid valves 9 and 11 in an open state and the third solenoid valve 13 in a closed state, the liquid 2 in the pressure tank 3 can be delivered to the spray pipe 7 by the pressure of the compressed air, and a fine mist can be sprayed from the spray nozzle 6 by this delivery. Furthermore, by closing the second solenoid valve 11 and simultaneously opening the third solenoid valve 13 for a required time, the increase in liquid pressure in the spray pipe 7 after the OFF signal of the second solenoid valve 11 is output can be reduced by discharging a required amount of the liquid 2 through the outlet 19 of the discharge pipe 15. With the first solenoid valve 9 in a closed state and the third and fourth solenoid valves 13 and 16 in an open state, the compressed air is supplied to the spray pipe 7 through the second air supply pipe 17, whereby the liquid in the spray pipe 7 is discharged through the outlet 19 of the discharge pipe 15, thereby emptying the inside of the spray pipe 7.

[0026] This will be explained in detail below. The pressure tank 3 is a sealed tank that contains the liquid 2 to be sprayed. For example, 10 to 20 liters of liquid 2 can be contained. The liquid 2 is, for example, a liquid mixed with lactic acid bacteria. In this embodiment, the liquid 2 is prepared in a liquid storage tank 20 and introduced into the pressure tank 3. For this purpose, the liquid storage tank 20 is directly connected to a water supply (reference numeral 14 in FIG. 1 is a water pipe), and the liquid 2 is prepared by mixing an appropriate amount of tap water with lactic acid bacteria. In FIG. 1, the liquid 2 is introduced into the pressure tank 3 from the liquid storage tank 20 by gravity. When compressed air is supplied into the pressure tank 3 from the compressed air supply source 5, the liquid 2 contained in the pressure tank 3 is pushed by the pressure of the compressed air and sent to the spray pipe 7.

[0027] The pipes used in each embodiment of the present invention, including the spray pipe 7, are preferably made of resin from the standpoint of cost and ease of handling in system construction due to their flexibility. In this embodiment, the spray pipe 7 is bent in a serpentine manner and installed on the ceiling of the cowshed, and its total length is long, at 100 to 150 m. The total length depends on the size of the facility and can be set relatively short, for example, 30 to 40 m, or can be set as long as 200 m or more. In addition, the installation height of the spray pipe 7 in the case of the cowshed is usually 2.0 to 2.5 m from the floor.

[0028] A large number of the spray nozzles 6 are attached to the spray pipe 7 at intervals of, for example, about 3 meters. The spray nozzles 6 may or may not have a check valve.

[0029] The pressure tank 3 and the liquid storage tank 20 are connected by a liquid introduction pipe 22 equipped with a first check valve 21. The pressure tank 3 and the compressed air supply source 5 are connected by the first air supply pipe 10, and the first air supply pipe 10 is equipped with the first solenoid valve 9 on the compressed air supply source 5 side and a second check valve 23 on the pressure tank 3 side.

[0030] The pressure tank 3 and the spray pipe 7 are connected by a liquid supply pipe 12, which has the second solenoid valve 11 installed on the pressure tank 3 side and a third check valve 25 installed on the spray pipe 7 side. The discharge pipe 15, which has the third solenoid valve 13 installed, is connected to a required portion of the spray pipe 7, in this embodiment to a tip 26 of the spray pipe 7, and a required amount of the liquid 2 discharged from the discharge pipe 15 is allowed to flow into the liquid storage tank 20 for reuse. The compressed air supply source 5 and the spray pipe 7 are connected by the second air supply pipe 17, which has the fourth solenoid valve 16 installed on the compressed air supply source 5 side and a fourth check valve 29 installed on the spray pipe 7 side. The solenoid valves 9, 11, 13, and 16 are controlled as required by a control unit 30.

[0031] The first to fourth check valves 21, 23, 25, and 29 block the flow of the liquid and the air from the high-pressure side to the low-pressure side. The first check valve 21 prevents compressed air supplied to the pressure tank 3 from flowing into the liquid storage tank 20 and also prevents the liquid 2 in the pressure tank 3 from flowing into the liquid storage tank 20 due to the compressed air. The second check valve 23 prevents the liquid 2 in the pressure tank 3 from flowing into the first solenoid valve 9. The third check valve 25 prevents the liquid in the spray pipe 7 from flowing into the second solenoid valve 11 and prevents the compressed air from flowing into the second solenoid valve 11 when the fourth solenoid valve 16 is open. The check valve 29 also prevents the liquid in the pressure tank 3 from flowing into the solenoid valve 16.

[0032] And the spray nozzle 6 To spray a fine mist from the 2 As shown in FIG. 1, under the control of the control unit 30, the first and second solenoid valves 9 and 11 are opened and the third solenoid valve 13 is closed to supply compressed air into the pressure tank 3, thereby sending the liquid 2 in the pressure tank 3 to the spray pipe 7, and by this delivery, a fine mist can be sprayed from the spray nozzle 6.

[0033] When the spraying is performed intermittently (for example, when the spraying continues for 10 seconds and then stops for 3 minutes), the second solenoid valve 11 is closed to stop the spraying. However, even when the control unit 30 outputs an OFF signal for the second solenoid valve 11, the first solenoid valve 11 does not close instantaneously, resulting in an operating time lag. Although this operating time lag is extremely short compared to the operating time lag (3 to 5 seconds) of the pump used in Patent Document 1, even during this time, the liquid 2 flows into the spray pipe 7, causing an increase in liquid pressure within the spray pipe 7. If this state is left unchecked, the liquid pressure will gradually decrease due to the spraying from the spray nozzle 6. However, because this decrease is gradual, residual pressure within the spray pipe 7 (insufficient liquid pressure that prevents proper spraying from the spray nozzle 6) will cause liquid to drip from the opening 31 of the spray nozzle 6.

[0034] Therefore, in the present invention, the second solenoid valve 11 is closed and the third solenoid valve 13 is opened at the same time under the control of the control unit 30. Here, "closed" means outputting an OFF signal for the second solenoid valve 11, and "simultaneously" includes, within a range of up to 0.1 seconds, immediately before and after the output of the OFF signal for the second solenoid valve 11.

[0035] In this way, by closing the second solenoid valve 11 and simultaneously opening the third solenoid valve 13 for the required time, the increase in liquid pressure in the spray pipe 7 after the second solenoid valve 11 outputs an off signal can be reduced within a short time (for example, 1 second) by naturally discharging a required amount of liquid through the outlet 19 of the discharge pipe 15. The required time is the time required for the required amount of liquid to be discharged through the outlet 19, and this time is set appropriately depending on the amount of liquid that has flowed into the spray pipe 7 during the operation time lag. Note that this time is set based on experimental values.

[0036] This effectively prevents dripping of the liquid from the opening 31 of the spray nozzle 6 caused by the residual pressure in the spray pipe 7. When the spray nozzle 6 is equipped with a check valve, the dripping can be prevented even more effectively. The liquid discharged from the outlet 19 of the discharge pipe 15 in this manner flows into the liquid storage tank 20 and is reused.

[0037] When the spray system 1 is shut down after the day's spraying work is completed, liquid 2 remains in the spray pipe 7, etc., and in cold regions, the remaining liquid may freeze during the shutdown period, making it impossible to deliver the liquid or damaging the spray pipe 7. Furthermore, if the operation of the spray system 1 is seasonal, the shutdown of the spray system may be prolonged, causing the liquid and lactic acid bacteria remaining in the spray pipe 7, etc. to decay, or causing corrosion of the pipes and equipment, requiring extensive maintenance.

[0038] Therefore, in this embodiment, when the spraying operation of the spray system 1 for the day is completed, as shown in FIG. 3 , the first solenoid valve 9 is closed, and the fourth solenoid valve 16 and the third solenoid valve 13 are opened, and compressed air from the compressed air supply source 5 is supplied to the spray pipe 7 via the second air supply pipe 17 for a required time period taking into account the length of the spray pipe 7. At this time, the third check valve 25 prevents the compressed air from flowing into the second solenoid valve 11. This allows the liquid 2 in the spray pipe 7 to be discharged through the outlet 19 of the discharge pipe 15 and flow into the liquid storage tank 20, thereby emptying the spray pipe 7. Emptying the spray pipe 7 in this manner not only ensures hygiene of the spray system 1, but also reduces the effort required for maintenance of the spray system 1 by preventing corrosion of the equipment, thereby facilitating maintenance.

[0039] Since the liquid in the liquid supply pipe 12 and the liquid introduction pipe 22 is located at a low position and is short, it can be discharged in a short time by manually opening the on-off valves attached to them. In contrast, the liquid in the spray pipe 7, which is located at a high position and is long as in the cowshed of this embodiment, cannot be discharged in a short time by manually opening the valves. Therefore, in the present invention, a configuration is adopted in which the spray system can be put into an operating state in which the spray pipe 7 is emptied, and by putting it into this operating state, the liquid in the spray pipe 7, which is located at a high position and is long, can be smoothly discharged in a short time.

[0040] When spraying begins the next day, as described above, as shown in FIG. 2, the first and second solenoid valves 9 and 11 are opened and the third solenoid valve 13 is closed to supply compressed air into the pressure tank 3, thereby sending the liquid in the pressure tank 3 to the spray pipe 7, and this sending allows a fine mist to be sprayed from the spray nozzle 6.

[0041] In addition,When spraying starts on the following day, the third solenoid valve 13 is closed and liquid 2 is sent to the empty spray pipe 7, so the air that was present in the spray pipe 7 remains in a compressed state at the tip of the spray pipe 7. Therefore, when spraying is stopped for the first time thereafter, if the second solenoid valve 11 is closed and the third solenoid valve 13 is opened at the same time, the compressed air will be discharged from the outlet 19 together with the liquid in the spray pipe 7.

[0042] As the spraying continues, the liquid 2 in the pressure tank 3 decreases, but for example, by closing the second solenoid valve 11 during the operation stop period during the intermittent operation (during this operation stop period, the first solenoid valve 9 is closed), the liquid 2 in the liquid storage tank 20 is introduced into the pressure tank 3 through the liquid inlet pipe 22 by gravity flow.

[0043] During the period when the spraying continues, the compressed air is supplied into the pressure tank 3, and therefore the pressure inside the pressure tank 3 increases. Therefore, during this period, the liquid is not introduced into the pressure tank 3 from the liquid storage tank 20. It takes The gravity flow system for introducing liquid has a simple structure because it can introduce liquid without using a pump, and is also economical because it does not consume electricity.

[0044] 4 shows a case where an ejector 33 is attached to the discharge pipe 15. The ejector 33 has a supply port 35, a suction port 36, and a discharge port 37 that are internally connected to one another, with the supply port 35 connected to the compressed air supply source 5 via a fifth solenoid valve 39 and the suction port 36 connected to the discharge port 19 of the discharge pipe 15. When the ejector 33 is used, negative pressure can be generated by opening the third solenoid valve 13 and the fifth solenoid valve 39 at the same time, causing compressed air from the compressed air supply source 5 to be ejected from the supply port 35 toward the discharge port 37. The liquid 2 in the spray pipe 7 is sucked through the suction port 36 by the action of this negative pressure, and the sucked liquid is discharged from the discharge port 37 and flows into the liquid storage tank 20.

[0045] When the configuration in which the ejector 33 is attached to the discharge pipe 15 in this manner is adopted, by closing the second solenoid valve 11 and simultaneously opening the third solenoid valve 13 and the fifth solenoid valve 39, the increase in liquid pressure in the spray pipe 7 after the OFF signal is output can be instantly reduced by the quick discharge action of the liquid 2 by the ejector 33. This makes it possible to reliably prevent the dripping of liquid from the opening 31 of the spray nozzle 6 caused by the residual pressure in the spray pipe 7 even in the case where the spray nozzle 6 does not have a check valve.

[0046] In contrast to the present invention, which includes the ejector 33, paragraph 0031 of Patent Document 1 states, "In the present invention, a vacuum pump or the like may be connected to the piping separately. Connecting a vacuum pump allows for more reliable depressurization." The vacuum pump employed in Patent Document 1 requires a large vacuum tank and also requires a device to stop the pump and drain the accumulated water in the vacuum tank. This increases the complexity and cost of the vacuum pump device, which increases the manufacturing cost of the spray system. In contrast, the ejector used in the present invention has the advantage of being small, lightweight, and simply constructed, yet capable of reliably reducing the pressure inside the spray pipe 7, without significantly increasing equipment costs.

[0047] In a configuration in which the ejector 33 is attached to the discharge pipe 15, if the ejector 33 is operated prior to opening the third solenoid valve 13 (for example, 5 seconds before opening), the operation can create a vacuum in the discharge pipe 15. In such a configuration, a vacuum is already created in the discharge pipe 15 before the third solenoid valve 13 is opened. Therefore, when the third solenoid valve 13 is opened, the required amount of liquid that is causing the pressure rise in the spray pipe 7 can be discharged more quickly, and the pressure in the spray pipe 7 can be more reliably reduced. This makes it possible to more reliably prevent the liquid from dripping.

[0048] As described above, the spray system 1 according to the present invention employs a configuration in which the liquid to be sprayed is pressurized not by a pump as in Patent Document 1, but by utilizing the air pressure of compressed air from the compressed air supply source 5. Therefore, in cooperation with the opening and closing operations of the various solenoid valves, dripping from the spray nozzle 6 can be effectively prevented. Additionally, the spray system 1 utilizes the compressed air from the compressed air supply source 5 not only to deliver the liquid 2 but also to empty the spray pipe 7 and to operate the ejector 33, making multifaceted use of the compressed air from the compressed air supply source 5. The resulting simplification of the system and the resulting economy are also features of the spray system according to the present invention. Example 2

[0049] 5 shows another embodiment of the spraying system 1 according to the present invention, which, like in embodiment 1, is installed in a livestock barn, such as a cow barn. The spraying system 1 comprises a first pressure tank 3 (3a) and a second pressure tank 3 (3b) in which a liquid 2 is stored, a compressed air supply source 5 for supplying compressed air, and a spray pipe 7 equipped with a spray nozzle 6 for spraying mist. The first and second pressure tanks 3a, 3b are connected to each other by a first air supply pipe 10 equipped with a first solenoid valve 9. The first and second pressure tanks 3a, 3b are connected to each other by a liquid supply pipe 12 equipped with a second solenoid valve 11. A discharge pipe 15 is connected to a required portion of the spray pipe 7 via a third solenoid valve 13. The open state of the first and second solenoid valves 9, 11 for the first pressure tank 3a and the open state of the first and second solenoid valves 9, 11 for the second pressure tank 3b are alternately repeated at predetermined time intervals. The first and second pressure tanks 3a, 3b are connected to the compressed air supply source 5 by a first air supply pipe 10 having a first solenoid valve 9 installed therein, and the first and second pressure tanks 3a, 3b are connected to the spray pipe 7 by a liquid supply pipe 12 having a second solenoid valve 11 installed therein.

[0050] By supplying the compressed air into the first pressure tank 3a or the second pressure tank 3b with the first and second solenoid valves 9, 11 in an open state and the third solenoid valve 13 in a closed state, the liquid in the pressure tank 3a or the pressure tank 3b can be delivered to the spray pipe 7 by the pressure of the compressed air, and this delivery can spray a fine mist from the spray nozzle 6. Furthermore, by closing the second solenoid valve 11 and opening the third solenoid valve 13 at the same time, the increase in liquid pressure in the spray pipe 7 after the second solenoid valve 11 outputs an off signal can be reduced by discharging a required amount of the liquid 2 through the outlet 19 of the discharge pipe 15. Then, with the first solenoid valve 9 in a closed state and the third and fourth solenoid valves 13, 16 in an open state, the compressed air is delivered to the spray pipe 7 via the second air supply pipe 17. At this time, the third check valve 25 prevents the compressed air from flowing into the second solenoid valve 11. This allows the liquid 2 in the spray pipe 7 to be discharged through the outlet 19 of the discharge pipe 15 and flow into the liquid storage tank 20, thereby emptying the inside of the spray pipe 7.

[0051] This will be described in detail below. The spray system 1 according to this embodiment is characterized in that it is configured using two pressure tanks, a first pressure tank 3a and a second pressure tank 3b, rather than using one pressure tank 3 as in the first embodiment, and the open state of the first and second solenoid valves 9, 11 for the first pressure tank 3a and the open state of the first and second solenoid valves 9, 11 for the second pressure tank 3b are alternately repeated at predetermined time intervals.

[0052] The first and second pressure tanks 3a, 3b are both sealed tanks having the same configuration and contain the liquid to be sprayed 2. The first and second pressure tanks 3a, 3b can contain, for example, 10 to 20 liters of liquid.

[0053] The liquid 2 is, for example, a liquid mixed with lactic acid bacteria. In this embodiment, the liquid 2 is prepared in a liquid storage tank 20 and introduced into the pressure tanks 3a and 3b. For this purpose, the liquid storage tank 20 is directly connected to a water supply (reference numeral 14 in FIG. 5 is a water pipe), and the liquid 2 is prepared by mixing lactic acid bacteria into an appropriate amount of tap water that flows in.

[0054] The liquid 2 is introduced from the liquid storage tank 20 into the first and second pressure tanks 3a and 3b by gravity. When compressed air from the compressed air supply source 5 is supplied to the required pressure tank (the first pressure tank 3a or the second pressure tank 3b), the liquid 2 contained in the pressure tank is pushed by the pressure of the compressed air and sent to the spray pipe 7. As in the first embodiment, the pipes used in each embodiment of the present invention, including the spray pipe 7, are preferably made of resin from the standpoint of cost and ease of handling in system construction due to their flexibility. A large number of spray nozzles 6 are attached to the spray pipe 7 at intervals of, for example, about 3 meters. The spray nozzle 6 may or may not have a check valve.

[0055] As described above, the first and second pressure tanks 3a, 3b and the liquid storage tank 20 are connected by a liquid introduction pipe 22 equipped with a first check valve 21. The first and second pressure tanks 3a, 3b and the compressed air supply source 5 are connected by the first air supply pipe 10, and the first air supply pipe 10 is equipped with a first solenoid valve 9 on the compressed air supply source 5 side and a second check valve 23 on the first and second pressure tanks 3a, 3b side.

[0056] The first and second pressure tanks 3a, 3b are connected to the spray pipe 7 by a liquid supply pipe 12, and a second solenoid valve 11 is installed in the liquid supply pipe 12 on the side of the first and second pressure tanks 3a, 3b, and a third check valve 25 is installed on the side of the spray pipe 7. The discharge pipe 15, in which a third solenoid valve 13 is installed, is connected to a required portion of the spray pipe 7, in this embodiment, a tip portion 26 of the spray pipe 7, and a required amount of the liquid 2 discharged from the discharge pipe 15 flows into the liquid storage tank 20 for reuse. In addition, the compressed air supply source 5 and the spray pipe 7 are connected by a second air supply pipe 17. The second air supply pipe 17 has the fourth solenoid valve 16 installed on the side of the compressed air supply source 5 and a fourth check valve 29 installed on the side of the spray pipe 7. The solenoid valves 9, 11, 13, and 16 are controlled as required by the control unit 30. The functions of the first to fourth solenoid valves 9, 11, 13, and 16 are the same as those described above.

[0057] Next, spray control of the spray system 1 according to this embodiment will be described. As described above, the spray system 1 according to this embodiment is configured so that the open state of the first and second solenoid valves 9, 11 for the first pressure tank 3a and the open state of the first and second solenoid valves 9, 11 for the second pressure tank 3b are alternately repeated at predetermined time intervals. That is, when the first and second solenoid valves 9, 11 for either the first or second pressure tank 3a, 3b are in the open state, the first and second solenoid valves 9, 11 for the other pressure tank are in the closed state.

[0058] Now, when the liquid 2 in the first pressure tank 3a is to be delivered to the spray pipe 7, the first and second solenoid valves 9 and 11 for the first pressure tank 3a are opened and the third solenoid valve 25 is closed, and compressed air is supplied into the first pressure tank 3a. This delivers the liquid 2 in the first pressure tank 3a to the spray pipe 7, causing the spray nozzle 7 to spray a fine mist. This control, for example, repeats a cycle of continuing the spray for 10 seconds and then stopping for 3 minutes, until the liquid level in the first pressure tank 3a drops to a set value. Thereafter, the pressure tank is switched from the first pressure tank 3a to the second pressure tank 3b, and the liquid 2 in the second pressure tank 3b is delivered to the spray pipe 7, as shown in FIG. 7, and the cycle is repeated. This spraying reduces the amount of liquid 2 in the first and second pressure tanks 3a and 3b, but the liquid 2 in the liquid storage tank 20 is introduced into the stopped pressure tanks by gravity through the liquid introduction pipe 22.

[0059] It should be noted that, since compressed air is supplied to the pressure tank in operation and the pressure inside the tank is increased, the liquid 2 in the liquid storage tank 20 does not flow into the pressure tank.

[0060] In the spray system 1 of this embodiment, as described above, liquid is introduced into a pressure tank that is in a stopped state, and therefore, by alternately repeating the open states of the first and second solenoid valves 9, 11 for the first and second pressure tanks 3a, 3b as described above, spraying in the spray pipe 7 can be performed continuously.

[0061] As described above, the spray system 1 according to the present invention is characterized in that continuous operation is possible by alternately using the first and second pressure tanks 3a and 3b. Furthermore, since the pressure tank is replenished with liquid when it is stopped, the volumes of the first and second pressure tanks 3a and 3b can be small, which allows for a compact spray system and is economical in that it reduces equipment costs.

[0062] When the spraying is performed intermittently as described above, to stop the spraying, the second solenoid valve 11 associated with the first pressure tank 3a or the second solenoid valve 11 associated with the second pressure tank 3b is closed, but the second solenoid valve 11 does not close instantaneously even when an OFF signal for the second solenoid valve 11 is output from the control unit 30, and an operating time lag occurs during this time. As described in Example 1, this operating time lag causes dripping from the opening 31 of the spray nozzle 6.

[0063] Therefore, in the invention according to this embodiment, the second solenoid valves 11 associated with the first and second pressure tanks 3a, 3b are closed and the third solenoid valve 13 is opened for a required time at the same time, as in embodiment 1. As in embodiment 1, "closing" means outputting an OFF signal for the second solenoid valve 11, and "simultaneously" includes, within a range of up to 0.1 seconds, immediately before and after the output of the OFF signal for the second solenoid valve 11.

[0064] This allows the increase in liquid pressure in the spray pipe 7 after the second solenoid valve 11 outputs an off signal to be reduced within a short period of time (e.g., 1 second) by allowing the required amount of liquid to be discharged naturally through the outlet 19 of the discharge pipe 15.

[0065] The required time is the time required for the required amount of liquid to be discharged from the discharge port 19, and this time is set appropriately depending on the amount of liquid that has flowed into the spray pipe 17 during the operation time lag. This time is set based on experimental values.

[0066] This effectively prevents dripping from the opening 31 of the spray nozzle 6 caused by residual pressure in the spray pipe 7. When the spray nozzle 6 is equipped with a check valve, dripping can be prevented even more effectively. The liquid discharged from the outlet 19 of the discharge pipe 15 in this manner flows into the liquid storage tank 20 and is reused.

[0067] When the spray system 1 is shut down after the day's spraying work is completed, liquid 2 remains in the spray pipe 7, etc., but as explained in Example 1, in cold regions, the remaining liquid may freeze during the shutdown period, making it impossible to deliver the liquid or damaging the spray pipe 7. Furthermore, if the operation of the spray system 1 is seasonal, the shutdown of the spray system 1 may be prolonged, causing the liquid and lactic acid bacteria remaining in the spray pipe, etc. to decay, or causing corrosion of the pipes and equipment, thereby shortening the life of the spray system.

[0068] Therefore, in this embodiment, when the spraying operation of the spray system for one day is completed, as shown in Fig. 8, the first solenoid valves 9 associated with the first and second pressure tanks 3a, 3b are closed, and the fourth solenoid valve 16 and the third solenoid valve 13 are opened, and compressed air from the compressed air supply source 5 is supplied to the spray pipe 7 via the second air supply pipe 17 for a required time period taking into consideration the length of the spray pipe 7. At this time, the third check valve 25 prevents the compressed air from flowing into the second solenoid valve 11.

[0069] As a result, the liquid 2 in the spray pipe 7 can be discharged through the outlet 19 of the discharge pipe 15 and flow into the liquid storage tank 20, thereby emptying the inside of the spray pipe 7. As in Example 1, by operating the system in the above-described operating state, the liquid in the long spray pipe 7, which is placed at a high place, can be smoothly discharged in a short time. By emptying the inside of the spray pipe in this manner, hygiene of the spray system can be ensured, and the prevention of corrosion of the equipment can reduce the effort required for maintenance of the spray system, making maintenance easier.

[0070] When spraying begins the next day, as described above, as shown in Figures 6 and 7, the first and second solenoid valves 9 and 11 are opened and the third solenoid valve 13 is closed to supply compressed air into the pressure tank, thereby sending the liquid in the pressure tank to the spray pipe 7, and this sending allows a fine mist to be sprayed from the spray nozzle 6.

[0071] When spraying starts on the following day, the third solenoid valve 13 is closed and liquid 2 is sent to the empty spray pipe 7, so the air that was present in the spray pipe 7 remains in a compressed state at the tip of the spray pipe 7. Therefore, when spraying is stopped for the first time thereafter, if the second solenoid valve 11 is closed and the third solenoid valve 13 is opened at the same time, the compressed air will be discharged from the outlet 19 together with the liquid in the spray pipe 7.

[0072] As the spraying continues, the liquid 2 in the pressure tank 3 decreases, but for example, by closing the second solenoid valve 11 during the operation stop period during the intermittent operation (during this operation stop period, the first solenoid valve 9 is closed), the liquid 2 in the liquid storage tank 20 is introduced into the pressure tank 3 through the liquid inlet pipe 22 by gravity flow.

[0073] 4 shows a case where an ejector 33 is attached to the discharge pipe 15, as in the first embodiment. The ejector 33 has a supply port 35, a suction port 36, and a discharge port 37 that are internally connected to one another, with the supply port 35 connected to the compressed air supply source 5 via a fifth solenoid valve 39 and the suction port 36 connected to the discharge port 19 of the discharge pipe 15. When the ejector 33 is used, negative pressure can be generated by opening the third solenoid valve 13 and the fifth solenoid valve 39 at the same time, causing compressed air from the compressed air supply source 5 to be ejected from the supply port 35 toward the discharge port 37. The liquid 2 in the spray pipe 7 is sucked through the suction port 36 by the action of this negative pressure, and the sucked liquid is discharged from the discharge port 37 and flows into the liquid storage tank 20.

[0074] In this manner, when the configuration in which the ejector 33 is attached to the discharge pipe 15 is adopted, the increase in liquid pressure in the spray pipe after the second solenoid valve 11 outputs an OFF signal can be instantly reduced by the quick discharge action of the ejector 33 of the liquid 2. This makes it possible to reliably prevent the liquid from dripping from the opening 31 of the nozzle 6 due to the residual pressure in the spray pipe 7 even when the spray nozzle 6 does not have a check valve.

[0075] In the case of adopting a configuration in which the ejector 33 is attached to the discharge pipe 15, if the ejector 33 is operated prior to opening the third solenoid valve 13 (for example, 5 seconds before opening), as in the first embodiment, the operation can create a vacuum in the discharge pipe 15. In this configuration, since a vacuum is already created in the discharge pipe 15 before the third solenoid valve 13 is opened, the required amount of the liquid causing the pressure rise in the spray pipe 7 can be more quickly discharged at the same time as the third solenoid valve 13 is opened, and the pressure in the spray pipe 7 can be more effectively reduced. This makes it possible to more reliably prevent the liquid from dripping.

[0076] As described above, the spray system 1 according to the present invention employs a configuration in which the liquid to be sprayed is pressurized not by a pump as in Patent Document 1, but by utilizing the air pressure of compressed air from the compressed air supply source 5. Therefore, in cooperation with the opening and closing operations of the various solenoid valves, dripping from the spray nozzle 6 can be effectively prevented. Furthermore, the spray system 1 utilizes the compressed air from the compressed air supply source 5 not only to deliver the liquid 2 but also to empty the spray pipe 7 and to operate the ejector 33, making multifaceted use of the compressed air from the compressed air supply source 5. The resulting simplification of the system and the resulting economy are also features of the spray system according to the present invention.

[0077] In addition, the spray system 1 according to this embodiment includes the first and second pressure This system is characterized by the fact that continuous operation is possible by alternately using the tanks 3a and 3b. Furthermore, because the liquid is replenished to the pressure tank when it is stopped, the volumes of the first and second pressure tanks 3a and 3b can be small, which allows for a compact spray system and is economical in that it reduces equipment costs. Example 3

[0078] The present invention is by no means limited to the above-described embodiments, and it goes without saying that various design modifications are possible within the scope of the claims. Examples of such modifications are as follows.

[0079] (1) The liquid 2 can be selected appropriately depending on the field of application of the spray system 1 of the present invention. For example, it may consist of only water to combat heatstroke. However, when the spray system of the present invention is used to improve the immune system of animals kept in livestock barns such as cowsheds, pig barns, and chicken coops, to reduce odors in livestock barns, or to improve plant growth through foliar spraying, it is preferable to use a liquid containing lactic acid bacteria, as described above. The lactic acid bacteria used should be of an appropriate strain depending on the application of the spray system 1 of the present invention. Furthermore, a liquid containing mint or other herbal medicines may be used for pest control, or a liquid containing a bactericidal agent such as sodium hypochlorite may be added to inhibit bacterial growth.

[0080] (2) In the above embodiment, the liquid discharged from the outlet of the discharge pipe flows into the liquid storage tank 20, but it may also be discharged into a drain.

[0081] (3) The spray nozzle 6 has an opening size appropriate for the installation location of the spray system 1 according to the present invention. When the spray system 1 is installed in, for example, a livestock barn, a spray nozzle with a small opening size is used so as to generate a fine mist. On the other hand, when the spray system is installed in, for example, a plant cultivation greenhouse, a spray nozzle with a relatively large opening size is used.

[0082] (4) In the above embodiment, the discharge pipe 15 for discharging the liquid 2 is provided at the tip of the spray pipe 7, but it may be provided at any location on the spray pipe 7 as long as it does not interfere with the spray. Figure 9 shows one example, in which the spray pipe is annular and the discharge pipe 15 is provided at the liquid delivery portion 41 for the annular portion 40.

[0083] (5) Figure 10 shows another liquid preparation device for preparing the liquid containing lactic acid bacteria. In this figure, the liquid preparation device is configured by connecting the supply port of a cartridge 41 containing a lactic acid bacteria solution to a water pipe. Using negative pressure generated by the flow rate of tap water, the lactic acid bacteria solution in the cartridge is gradually mixed into the tap water in the required amount, thereby preparing a liquid containing lactic acid bacteria at the required concentration. This configuration allows the device to continue operating simply by replacing the used cartridge, eliminating the need for cleaning the tank, as is required when using the liquid storage tank 20.

[0084] (6) The pressure tank 3 may be one as in Example 1, two as in Example 2, or three or more depending on the length of the spray pipe. In this case, the pressure tank 2 used for spraying is changed sequentially in accordance with the explanation in Example 2.

[0085] (7) The spray system 1 according to the present invention can be widely installed in places where the generation of fine mist is required, such as hospitals and nursing homes, in addition to the fields of livestock farming and agriculture described above, and can be used to provide antiviral and antibacterial measures by spraying a liquid containing lactic acid bacteria, etc., and can also be applied in the fields of air cooling, relaxation, aromatherapy, etc. Therefore, the spray system 1 according to the present invention can be used throughout the year by selecting the liquid 2 used.

[0086] In these installation fields, the installation height of the spray pipe 7 is set as required according to the purpose of installation. The case of a cowshed has been explained in the above embodiment, but in other cases, such as the above-mentioned vegetable cultivation greenhouse, the installation height is usually about 1.8 m, and in cases where spraying is performed from the side of the greenhouse, it may be about 1.0 m. [Explanation of symbols]

[0087] 1. Spraying system 2 liquid 3. Pressure Tank 3a First pressure tank 3b Second pressure tank 5. Compressed air supply source 6 spray nozzle 7 Spray tube 9. First solenoid valve 10 First air supply pipe 11 Second solenoid valve 12 Liquid supply pipe 13 Third solenoid valve 15 Discharge pipe 16 Fourth solenoid valve 17 Second air supply pipe 19 Outlet 20 Liquid storage tank 21 First check valve 22 Liquid introduction pipe 23 Second check valve 25 Third check valve 26 Tip part 29 Fourth check valve 30 Control Unit 31 Aperture 33 Ejector 35 Supply Port 36 Suction port 37 Exhaust port 39 Fifth solenoid valve

Claims

1. The apparatus comprises a pressure tank for storing a liquid, a compressed air supply source for supplying compressed air, and a spray pipe provided with a spray nozzle for spraying a mist, the pressure tank and the compressed air supply source are connected by an air supply pipe having a first solenoid valve interposed therein, the pressure tank and the spray pipe are connected by a liquid supply pipe having a second solenoid valve interposed therein, and a discharge pipe having a third solenoid valve interposed therein is connected to a required portion of the spray pipe, By supplying compressed air into the pressure tank with the first and second solenoid valves in an open state and the third solenoid valve in a closed state, the liquid in the pressure tank can be sent to the spray pipe by the pressure of the compressed air, and this sending can spray a mist from the spray nozzle.On the other hand, by closing the second solenoid valve and simultaneously opening the third solenoid valve for a required time, the increase in liquid pressure in the spray pipe after the off signal of the second solenoid valve is output can be reduced by discharging a required amount of the liquid from the outlet of the discharge pipe.

2. The apparatus comprises a pressure tank for storing a liquid, a compressed air supply source for supplying compressed air, and a spray pipe provided with a spray nozzle for spraying a mist, the pressure tank and the compressed air supply source are connected by a first air supply pipe having a first solenoid valve interposed therein, the pressure tank and the spray pipe are connected by a liquid supply pipe having a second solenoid valve interposed therein, a discharge pipe having a third solenoid valve interposed therein is connected to a required portion of the spray pipe, and the compressed air supply source and the spray pipe are connected by a second air supply pipe having a fourth solenoid valve interposed therein, by supplying the compressed air into the pressure tank with the first and second solenoid valves in an open state and the third solenoid valve in a closed state, the liquid in the pressure tank can be delivered to the spray pipe by the pressure of the compressed air, and by this delivery, mist can be sprayed from the spray nozzle; By closing the second solenoid valve and simultaneously opening the third solenoid valve for a required time, the increase in liquid pressure in the spray pipe after the OFF signal of the second solenoid valve is output can be reduced by discharging a required amount of the liquid from the outlet of the discharge pipe, A spray system characterized in that, with the first solenoid valve in a closed state and the third and fourth solenoid valves in an open state, the compressed air is supplied to the spray pipe via the second air supply pipe, thereby discharging the liquid in the spray pipe through the outlet of the discharge pipe and emptying the inside of the spray pipe.

3. the pressure tank comprises a first pressure tank and a second pressure tank; the first and second pressure tanks are connected to the compressed air supply source by a first air supply pipe having a first electromagnetic valve interposed therein, and the first and second pressure tanks are connected to the spray pipe by a liquid supply pipe having a second electromagnetic valve interposed therein; 3. A spray system according to claim 1, wherein the open state of the first and second solenoid valves for the first pressure tank and the open state of the first and second solenoid valves for the second pressure tank are alternately repeated at predetermined time intervals.

4. a first pressure tank and a second pressure tank for storing a liquid, a compressed air supply source for supplying compressed air, and a spray pipe provided with a spray nozzle for spraying a mist; The first and second pressure tanks are connected to the compressed air supply source by a first air supply pipe having a first electromagnetic valve installed therein, and the first and second pressure tanks are connected to the spray pipe by a liquid supply pipe having a second electromagnetic valve installed therein, and a discharge pipe is connected to a required portion of the spray pipe via a third electromagnetic valve, the first and second electromagnetic valves for the first pressure tank and the first and second electromagnetic valves for the second pressure tank are alternately opened and closed at predetermined time intervals, by supplying the compressed air into the first pressure tank or the second pressure tank with the first and second solenoid valves in an open state and the third solenoid valve in a closed state, the liquid in the pressure tank can be delivered to the spray pipe by the pressure of the compressed air, and the delivery can spray mist from the spray nozzle; Furthermore, by closing the second solenoid valve and simultaneously opening the third solenoid valve for a required time, the increase in liquid pressure in the spray pipe after the OFF signal of the second solenoid valve is output can be reduced by discharging a required amount of the liquid from the outlet of the discharge pipe, and A spray system characterized in that, with the first solenoid valve in a closed state and the third and fourth solenoid valves in an open state, the compressed air is supplied to the spray pipe via the second air supply pipe, thereby discharging the liquid in the spray pipe through the outlet of the discharge pipe and emptying the inside of the spray pipe.

5. The spray system according to any one of claims 1 to 4, characterized in that the supply port of an ejector having a supply port, a discharge port, and a suction port that are interconnected internally is connected to the compressed air supply source via a fifth solenoid valve, and the suction port is connected to the discharge outlet of the discharge pipe, and the third solenoid valve is opened and the fifth solenoid valve is opened at the same time to eject compressed air from the supply port toward the discharge port. By the action of negative pressure generated by this, a required amount of the liquid that is causing the pressure in the spray pipe to increase is sucked from the suction port and discharged from the discharge port.

6. 6. The spray system according to claim 5, wherein the ejector is operated before the third electromagnetic valve is opened, and the operation is controlled to create a vacuum in the discharge pipe.

7. 3. A spray system according to claim 1, wherein the lower part of the liquid storage tank is connected to the pressure tank, and the liquid in the liquid storage tank is supplied to the pressure tank by gravity when the first and second solenoid valves are closed.

8. A spray system as described in claim 3 or 4, characterized in that the lower part of the liquid storage tank is connected to the first and second pressure tanks, and the liquid in the liquid storage tank is supplied to the first pressure tank and / or the second pressure tank by gravity when the first and second solenoid valves are closed.

9. 8. The spray system according to claim 7, wherein the liquid discharged from the outlet of the discharge pipe flows into the liquid storage tank.

10. 9. The spray system according to claim 1, wherein the liquid is a liquid containing lactic acid bacteria.

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