JPH02265662A - Dropping preventive spray apparatus - Google Patents

Abstract

PURPOSE:To prevent the dropping of a liq. by controlling a second valve to open almost simultaneously with the closing of a spray control valve at the time of spray stoppage. CONSTITUTION:A liq. 2 is drawn in by a liq. pump 3 through a pipe 8 to be sent into a pipe 9. The liq. is then pressurized with the pressure created by pressing air in an accumulator 4 mounted to the pipe 9. By opening and closing a spray control valve 5, an intermittent control of the pressurized liq. spray from a spray nozzle 7 is effected. A branch passage valve 6 is opened in a short time simultaneously with the closing of the valve 5 to release the liq. discharge force at the time of closing the valve 5 into pipes 11 and 12 and prevent the dropping of the liq. from the spray nozzle 7. This permits a uniform attachement of the liq. particles to an object to be sprayed free from the droplets.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a device for spraying liquid.

[Conventional technology]

There are two methods to atomize liquid: one is to use compressed air to suck up the liquid using the Venturi effect when the compressed air is ejected, and blow it away with compressed air to atomize it. When spraying from a spray nozzle with a pore, the liquid that has been given rotational energy just before ejection is atomized and is sprayed from a pore. There is a method in which the liquid collides with the other particles, becomes atomized through pores, and is ejected and scattered. This method of intermittent spraying using liquid includes providing a spray control valve that opens and closes the flow of liquid between the liquid pump and the spray nozzle.

[Problems that Hatsuho is trying to solve]

When performing intermittent spray control using a liquid pump, when the spray is interrupted, the liquid becomes droplets and falls from the spray nozzle. This dripping liquid can cause smearing and non-uniformity on the object being misted. This is because in a mechanism that controls spraying of pressurized liquid using a spray control valve installed between the liquid pump and the spray nozzle, compressed air similar to the liquid enters the piping between the valve and the spray nozzle. When you close the valve and stop spraying, this compressed air expands and liquid drips from the spray nozzle.

In addition, even if piping is installed between the valve and the spray nozzle using a tube that expands somewhat, such as a nylon tube, there will be a difference in the pressure of the liquid in the piping between when spraying and when it is shut off. The piping tube contracts due to its elasticity, which causes liquid to drip from the spray nozzle as in the case described above. This dripping liquid is not only generated when the spray stops, but the droplets that remain attached to the nozzle are also blown out as drops at the beginning of the next spray start.

An object of the present invention is to provide a mechanism for preventing liquid from dripping in a spray device that uses a liquid pump to perform intermittent spray control.

[Means to solve problems]

In this device, a branch is further provided between the first valve for spray control and the nozzle, and a second valve of the branch path is provided to open and close the branch. When the liquid is sprayed from the spray nozzle, the first valve for spray control connected to the liquid pump is controlled to open and the second valve of the first branch path is closed, and when the spray is stopped, the first valve for spray control is controlled to be closed. By controlling the second valve in the branch passage to open for a short time at the same time that the valve closes, the liquid discharge force due to the residual pressure existing between the first valve for spray control and the nozzle is controlled to be controlled in the branch passage. It has a structure that allows the air to escape towards the

[For production]

When the first valve for spray control is closed to stop the flow of the pressurized liquid and cut off the spray, compressed air bubbles may remain between the first valve and the spray nozzle. . The compressed bubbles expand as the pressure is reduced, and the pressure due to the compressive force due to the elasticity of the tube is absorbed by opening the second valve of the nine branch paths for a short time at the same time as the first valve for spray control is closed. By directing the liquid to the branch path, dripping of the liquid from the spray nozzle is prevented. In other words, by releasing the pressurized discharge force of the remaining liquid to the branch path, not only does the force for discharging the liquid to the spray nozzle be reduced, but also negative pressure is applied inside the spray nozzle by the energy of the liquid flowing to the branch path. Since the dripping liquid is sucked up, it is possible to prevent the liquid from dripping that occurs at the beginning of the primary ejection.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

A liquid container 1 containing a liquid 20, a liquid pump 3 that sucks the liquid 2 through a pipe 8, a pipe 9 that leads the liquid from the liquid pump 3 to a valve 5, an accumulator 4 attached to the pipe 9, and an intermittent control of spraying. A valve 5 for spray control, a pipe 10 that leads the liquid from the valve 5 to the spray nozzle 7, a spray nozzle 7 that sprays the liquid, a pipe 11 branched from the pipe 10, and a valve 6 of a branch path connected to the pipe 11. It consists of a pipe 12 connected from the liquid container 1 to the liquid container 1.

The liquid 2 is sucked through a pipe 8 by a liquid pump 3 and sent to a pipe 9 by the liquid pump 3. The sent liquid compresses the air in the accumulator 4 attached to the pipe 9, and is pressurized by the resulting pressure. The spray control valve 5 controls the spraying of the pressurized liquid from the spray nozzle 7 intermittently by controlling the opening and closing of the valve. During intermittent spray control, at the same time valve 5 is closed, valve 6 in the branch passage is opened for a short time (approximately 0.2 seconds), and the expansion force of the compressed bubbles and the elasticity of the nylon tube, etc. that occur when valve 5 is closed. The liquid discharge force caused by the contraction force of the spray nozzle 7 is released to the piping 11.12, preventing the liquid from dripping from the spray nozzle 7, and the energy of the liquid flow generated when the liquid discharge force is released to the pipe 11.12 is used to Negative pressure is applied to the inside of the pump 7, and one drop of liquid is sucked up, thereby preventing the drop of liquid that occurs at the beginning of the first spout. At this time, when the valve 6 is opened, the liquid energized by the liquid discharge force flows into the pipe 1.
2 and returned to the liquid container 1.

Note that the reason why the valve 6 is closed after a short period of time (approximately 0.2 seconds) is to prevent free fall of the liquid in the spray nozzle 7. In the above embodiment, when the valve 5 is closed, the valve 6 is closed. This is a control that opens for a short period of time (approximately 0°2 seconds), but due to differences in physical properties such as specific gravity and viscosity of the liquid.

For example, if the liquid has a high viscosity, close the valve 5 and
Seconds later, just before the liquid drops from the spray nozzle 7, the valve 6 may be opened for a short time to suck up one drop of the liquid.

In addition, for liquids with low viscosity, the valve 5 should be closed at 0°1 to 0°.
The valve 6 may be opened 5 seconds before, the valve 5 may be closed while lowering the pressure in the spray nozzle 7, and the vent valve 6 may be closed for a short time.

〔effect〕

By carrying out the present invention, there is no dripping from the spray nozzle when spraying is interrupted or started, and uniform mist adhesion without dripping can be obtained on the object to be sprayed.

[Brief explanation of drawings]

Fig. 1 is a system diagram omitting valve control means showing an embodiment of a device suitable for carrying out the present invention. 1. Container for liquid, 2. Liquid. , 3...
-・Liquid pump, 4 Accumulator, 5.6゛°・・Valve, 7・・Spray nozzle, 8,9,10゜1
1.12 ・° Piping. that's all

Claims (1)

[Claims] (1) A first valve for spray control connected to a pressurized liquid, a spray nozzle attached to the other end of a pipe connected to the first valve, a branch pipe branched from the pipe, and other parts of the branch pipe In a spray device having a second valve attached to the end, when closing the first valve for spray control when the spray is cut off, the timing for opening the second valve is set at the same time as or before or after closing the first valve. A drip-preventing spray device characterized in that it is controlled to open for a short period of time.