JPH041665B2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention Industrial Field of Application The present invention sprays atomized paint from a spray gun toward a workpiece being conveyed by a conveyor, and forms an atomized paint between the spray gun and the workpiece. The present invention relates to a device for automatically extinguishing a fire when it occurs in an automatic electrostatic coating line that applies atomized paint to objects to be coated by the action of a high-potential electrostatic field.

Prior Art and Problems to be Solved by the Invention In automatic electrostatic coating lines, high voltage is applied between the spray gun and the object to be painted, so the electrode of the spray gun may come into contact with surrounding objects. Or, if paint adheres to the hanger of a conveyor that suspends and transports objects to be painted, resulting in poor conductivity, sparks are generated and the paint ignites, creating a risk of fire. For this reason, conventionally, a fire alarm was installed in the paint booth to issue an alarm as soon as a fire occurred and stop the spraying of paint.
Fire extinguishing agent was automatically sprayed from a nozzle installed inside the booth to extinguish the fire, but because the entire booth was filled with a large amount of extinguishing agent, large-scale extinguishing In addition to requiring additional equipment, the objects to be painted in the booth, the conveyor, and the spray gun were all covered with extinguishing agent and stained, which required a long time to remove.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fire extinguishing system that eliminates these drawbacks, can reliably extinguish fires with small-scale equipment, and does not stain the inside of the booth.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In the figure, reference numeral 1 denotes a conveyor for transporting objects to be coated a in one direction by suspending them from a number of hangers 2 hanging at regular intervals, and a reciprocating drive device 3 is installed in the vicinity of the conveyor. This reciprocating drive device 3 includes a reversible motor 5 installed at the bottom of a frame 4, and an endless chain 8 interposed between a drive sprocket 6 fixed to the output end of the reversible motor 5 and a driven sprocket 7 pivotally supported at the top of the frame 4. A support member 9 is supported by a guide rail (not shown) installed vertically in the center of the frame 4 so as to be freely movable up and down. A spray gun 10 is placed on the outside of both ends protruding from both left and right sides, and a fire extinguishing nozzle 11 is placed on the inside.
Each of them is attached toward the conveyance path of the object to be painted a. The spray gun 10 is connected to a high-pressure paint pump 22 via an air-driven on-off valve (not shown) built into its rear end, and an air cylinder for driving this on-off valve is supplied with pressurized air via an electromagnetic switching valve 13. In addition, an electrode (not shown) protruding near the paint spout 12 is connected to the negative electrode of a high voltage generator 16 via a cable 15, and the positive electrode of the high voltage generator 16 is connected to the ground. connected to conveyor 1 by hanger 2
It is connected to the object a to be painted via. The fire extinguishing nozzle 11 is connected to a cylinder 19 filled with a nonflammable gas such as nitrogen, carbon gas, or propane by opening an electromagnetic on-off valve 18. Further, above between the conveyor 1 and the reciprocating drive device 3, a sensor 20 that is activated by sensing heat, light, smoke, etc. is installed and connected to an input terminal of a control device 21.
The output terminal 1 is connected to the control circuit of the high voltage generator 16, the solenoid of the electromagnetic switching valve 13, and the electromagnetic shut-off valve 18, respectively.

Next, the operation of this embodiment will be explained.

During normal operation, the reversible motor 5 of the reciprocating drive device 3 rotates in alternate directions at fixed time intervals.
The spray gun 10 and fire extinguishing nozzle 11 move up and down with a constant stroke together with the support member 9 connected to the chain 8, and an on-off valve (not shown) opens due to the excitation of the electromagnetic switching valve 13, and paint is supplied from the high-pressure paint pump 22 to the spray gun 10. The paint is pumped under high pressure, is ejected at high speed from a small diameter paint spout 12 formed at the tip, and is atomized by friction with the air.
The spray gun 1 is driven by the high voltage generator 16.
Due to the action of the electrostatic field formed between the electrode at the tip of the spray gun 10 and the object a, the atomized paint is guided to the object a and is deposited on the surface of the object a. Sparks are generated when the hanger 2 contacts an object or the paint on the hanger 2 adheres to the hanger 2, causing poor conductivity, and when this ignites the atomized paint flow jetting out of the paint spout 12 of the spray gun 10, a flame is emitted. The flame spreads like a vessel and ignites the paint applied to the object to be painted. When the occurrence of this fire is detected by the sensor 20 and the signal is input to the control device 21, a lamp (not shown) lights up or a buzzer sounds, and at the same time, the high voltage generator 1
6 and the conveyor 1 are stopped, the electromagnetic switching valve 13 is de-energized, the supply of paint to the spray gun 3 is stopped, the flame ejected from the spray gun 10 is stopped, and the electromagnetic switching valve 18 is energized. The nonflammable gas in the cylinder 19 is ejected from the spout 17 at the tip of the extinguishing nozzle 11 toward the object a to be painted, thereby extinguishing the object a.

Although the spray gun 10 of this embodiment is an airless spray type, the present invention can be applied to various electrostatic spray guns such as an air spray type or a rotary cup type.

As specifically explained in the above embodiment,
The fire extinguishing device for an automatic electrostatic coating line of the present invention is provided with a reciprocating drive device that reciprocates a support member in a substantially vertical direction near a conveyor that conveys objects to be coated in a substantially horizontal direction, A spray gun that sprays atomized paint toward an object is attached, and a high-potential electrostatic field is formed between the spray gun and the object to be painted, so that the atomized paint jetted from the spray gun is directed toward the object to be painted. In an automatic painting line, the nonflammable gas is guided to the support or another support that is driven by the reciprocating drive device and reciprocates in a substantially vertical direction together with the support, and the nonflammable gas is applied to the surface of the nonflammable gas. The gist is that a fire extinguishing nozzle that spouts out toward the painted object is installed, and a nonflammable gas is spouted from the fire extinguishing nozzle when a fire occurs, and the fire extinguishing nozzle is driven back and forth together with the spray gun. The ejected nonflammable gas is sprayed directly onto the burning object to be painted.
Moreover, it is sprayed repeatedly over the entire combustion range, so it can reliably extinguish a fire with a small amount of nonflammable gas, and has sufficient fire extinguishing ability even in small-scale equipment. The effect is that the painting line can be restarted quickly after extinguishing the fire without contaminating the equipment.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an outline of an embodiment of the present invention. 1: Conveyor, 3: Reciprocating drive device, 9: Support member, 10: Spray gun, 11: Fire extinguishing nozzle, 1
6: High voltage generator, 18: Open/close valve, 19: Cylinder, 20: Sensor, 21: Control device, a: Object to be coated.

Claims (1)

[Claims] 1. A spray gun that includes a reciprocating drive device that reciprocates a support member in a substantially vertical direction near a conveyor that conveys an object to be painted in a substantially horizontal direction, and that sprays atomized paint onto the support member toward the object to be painted. A high-potential electrostatic field is formed between the spray gun and the object to be painted, so that the atomized paint ejected from the spray gun is guided to the object to be painted, and is applied to the surface of the object. In the automatic painting line,
A fire extinguishing nozzle is attached to the support or another support that is driven by the reciprocating drive device and reciprocates in a substantially vertical direction together with the support, so that a fire extinguishing nozzle that spouts nonflammable gas toward the object to be coated is installed, and the fire extinguishing nozzle is installed when a fire occurs. A fire extinguishing system for an automatic electrostatic coating line, characterized in that it is configured to eject nonflammable gas from a fire extinguishing nozzle.